Group advertisement and confirmation for multicast broadcast services

Abstract

A method for multicast broadcast service (MBS) notification signaling includes receiving, by a user equipment (UE), downlink control information (DCI). The DCI is associated with at least a first radio network temporary identifier (RNTI) corresponding to an MBS-related notification and includes a field having a plurality of bits. One or more bits of the plurality of bits of the field indicate an update or change to one or more MBS-related parameters. The method also includes determining, based on an indication by the one or more bits, to monitor signaling indicating the updated or changed MBS-related parameters, and receiving MBS data based on the updated or changed MBS-related parameters.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority under 35 U.S.C. 119(e) to U.S. Provisional Patent Application No. 63 / 209,842, filed June 11, 2021 (the "Provisional Patent Application"), the contents of which are incorporated herein by reference. [Background technology]

[0002] The present invention is directed to 5G, the fifth generation mobile network. This is the new global wireless standard that succeeds 1G, 2G, 3G, and 4G networks. 5G enables networks designed to connect machines, objects, and devices.

[0003] More particularly, the present invention relates to an apparatus and method for notification signaling, including providing a framework for and enhancing existing signaling mechanisms to achieve efficient MBS-related notifications. Summary of the Invention

[0004] In an embodiment, the present invention provides a method for multicast broadcast service (MBS) notification signaling, including receiving downlink control information (DCI) by a user equipment (UE). The DCI is associated with at least a first radio network temporary identifier (RNTI) corresponding to an MBS-related notification and includes a field having a plurality of bits. One or more bits of the plurality of bits in the field indicate an update or change to one or more MBS-related parameters. The method also includes determining, based on the indication by the one or more bits, to monitor signaling indicating the updated or changed MBS-related parameters, and receiving MBS data based on the updated or changed MBS-related parameters. Receiving the downlink control information (DCI) may be based on a physical downlink control channel (PDCCH). Receiving the downlink control information (DCI) may be performed while the user equipment (UE) is in a radio resource control (RRC) connected state, or while the user equipment (UE) is in a radio resource control (RRC) idle state or an RRC inactive state. Receiving downlink control information (DCI) may also be based on monitoring a downlink control channel at a monitoring opportunity determined based on a discontinuous reception (DRX) procedure in a radio resource control (RRC) idle state or an RRC inactive state.

[0005] Preferably, the first Radio Network Temporary Identifier (RNTI) is a paging RNTI, and the downlink control information (DCI) is associated with the transmission of paging information. Furthermore, the first Radio Network Temporary Identifier (RNTI) may be a Multicast Broadcast Service (MBS)-RNTI. One or more bits of the multiple bits of this field indicate a Broadcast Control Channel (BCCH) change. The determination to monitor signaling associated with updated or changed Multicast Broadcast Service (MBS)-related parameters may further be based on the user equipment (UE) being an MBS UE. Preferably, the Multicast Broadcast Service (MBS)-related parameters include semi-persistent scheduling (SPS) configuration parameters for receiving MBS data.

[0006] The Multicast Broadcast Service (MBS) notification received based on the Downlink Control Information (DCI) indicates one or more of a notification type, a target MBS service type, a target MBS service or group identifier (ID), and an uplink feedback or response. The notification type includes at least one of a Multicast Broadcast Service (MBS) system information update, an MBS session start / activation or an MBS session stop / deactivation, an MBS configuration change before or during an active session, and an MBS count order for soliciting interest indications. The Multicast Broadcast Service (MBS) service type may be one of multiple MBS service types, including a multicast service type and a broadcast service type. The target Multicast Broadcast Service (MBS) service or group identifier (ID) may be from multiple target MBS service or group IDs, including an MBS paging ID and a temporary mobile group identity (TMGI). The uplink feedback or response includes a trigger to use and resource needs.

[0007] The plurality of bits comprises a flag indicating the presence of a multicast broadcast service (MBS) notification. Preferably, the flag includes a bit, a first value of the bit indicating the presence of a multicast broadcast service (MBS) notification, and a second value of the bit indicating the absence of an MBS notification. Importantly, the first value is 1 and the second value is 0, and the flag can be ignored by a non-multicast broadcast service (MBS) user equipment (UE). The plurality of bits of the field may include one or more first bits indicating a change in a multicast broadcast service (MBS) system information block (SIB). The multicast broadcast service (MBS) system information block (SIB) can indicate a random access resource. The random access resource is preferably used by the user equipment (UE) for multicast broadcast service (MBS) interest indication signaling.

[0008] The multicast broadcast service (MBS) notification may comprise an information element indicating a request for an MBS interest indication, and receipt of the MBS notification may trigger MBS interest indication signaling by a user equipment (UE). Transmission of the interest indication signaling may be based on a randomization seed or according to a probability. The method may also include receiving a configuration parameter indicating the randomization seed or the probability. The random access resource may include a first random access resource associated with a first beam. In that regard, the random access resource may be divided into multiple random access resource sets, each random access resource set of the multiple random access resource sets being associated with a corresponding beam or distribution unit (DU). One or more bits of the multiple bits of the field may include one of multiple values, and each value of the multiple values ​​may be mapped to a change or combination of changes.

[0009] The combination of changes or modifications may be pre-configured. The combination of changes or modifications is configurable. The method may also include receiving system information indicating the combination of changes or modifications and receiving one or more radio resource control (RRC) configuration parameters indicating the combination of changes or modifications. The one or more bits are preferably ignored by non-multicast broadcast service (MBS) user equipment (UE).

[0010] In an embodiment, the present invention provides a user equipment (UE) having one or more processors and a memory storing instructions, the instructions, when executed by the one or more processors, causing the UE to: receive downlink control information (DCI), the DCI being associated with at least a first radio network temporary identifier (RNTI) corresponding to an MBS-related notification, the DCI including a field including a plurality of bits, one or more of the plurality of bits of the field indicating an update or change to one or more MBS-related parameters; determine, based on the indication by the one or more bits, to monitor signaling indicating the updated or changed MBS-related parameters; and receive MBS data based on the updated or changed MBS-related parameters. Receiving the downlink control information (DCI) may be based on a physical downlink control channel (PDCCH). Receiving the downlink control information (DCI) may be performed while the user equipment (UE) is in a radio resource control (RRC) connected state, may be performed while the user equipment (UE) is in a radio resource control (RRC) idle state or an RRC inactive state, or may be performed based on monitoring the downlink control channel at a monitoring opportunity determined based on a discontinuous reception (DRX) procedure in the radio resource control (RRC) idle state or the RRC inactive state.

[0011] The first radio network temporary identifier (RNTI) is a paging RNTI, and the downlink control information (DCI) is associated with the transmission of paging information. The first radio network temporary identifier (RNTI) is a multicast broadcast service (MBS)-RNTI. One or more bits of this field may indicate a broadcast control channel (BCCH) change. Importantly, determining to monitor signaling associated with updated or changed multicast broadcast service (MBS)-related parameters may further be based on the user equipment (UE) being an MBS UE. The multicast broadcast service (MBS)-related parameters may include semi-persistent scheduling (SPS) configuration parameters for receiving MBS data, and the multicast broadcast service (MBS) notification received based on the downlink control information (DCI) indicates one or more of a notification type, a target MBS service type, a target MBS service or group identifier (ID), and uplink feedback or response.

[0012] The notification type may include at least one of a Multicast Broadcast Service (MBS) system information update, an MBS session start / activation or an MBS session stop / deactivation, an MBS configuration change before or during an active session, and an MBS count order for soliciting an interest indication. Preferably, the Multicast Broadcast Service (MBS) service type is one of a plurality of MBS service types including a multicast service type and a broadcast service type. The target Multicast Broadcast Service (MBS) service or group identifier (ID) may be from a plurality of target MBS service or group IDs including an MBS paging ID and a temporary mobile group identity (TMGI). The uplink feedback or response includes a trigger for use and resource needs. The plurality of bits may comprise a flag indicating the presence of a Multicast Broadcast Service (MBS) notification. The flag preferably includes a bit, a first value of which indicates the presence of a Multicast Broadcast Service (MBS) notification, and a second value of which indicates the absence of an MBS notification. In one embodiment, the first value is 1 and the second value is 0.

[0013] The flag may be ignored by non-Multicast Broadcast Service (MBS) user equipment (UE). The multiple bits of the field may include one or more first bits indicating a change in a Multicast Broadcast Service (MBS) System Information Block (SIB). The Multicast Broadcast Service (MBS) System Information Block (SIB) may indicate a random access resource. The random access resource may be used by the user equipment (UE) for Multicast Broadcast Service (MBS) interest indication signaling. In that regard, the Multicast Broadcast Service (MBS) notification may comprise an information element indicating a request for an MBS interest indication, and receipt of the MBS notification may trigger MBS interest indication signaling by the user equipment (UE). Transmission of the interest indication signaling may be based on a randomization seed or according to a probability. In that regard, the instructions, when executed by the one or more processors, may further cause the UE to receive a configuration parameter indicating the randomization seed or the probability.

[0014] The random access resources include a first random access resource associated with a first beam. The random access resources are preferably divided into a plurality of random access resource sets, and each random access resource set in the plurality of random access resource sets is preferably associated with a corresponding beam or distribution unit (DU). In one form, one or more bits of the plurality of bits of the field have one of a plurality of values, and each value of the plurality of values ​​is mapped to a combination of modifications or changes. The combination of modifications or changes may be preconfigured or configurable. When executed by the one or more processors, the instructions may further cause the UE to receive system information indicating the combination of modifications or changes, and may further cause the UE to receive one or more radio resource control (RRC) configuration parameters indicating the combination of modifications or changes. The one or more bits are preferably ignored by non-multicast broadcast service (MBS) user equipment (UE). [Brief explanation of the drawings]

[0015] [Figure 1] 1 illustrates an example system for mobile communications in accordance with some aspects of various exemplary embodiments of the present disclosure. [Figure 2A] 1 illustrates example radio protocol stacks for the user plane and control plane in accordance with certain aspects of various exemplary embodiments of the present disclosure. [Figure 2B] 1 illustrates example radio protocol stacks for the user plane and control plane in accordance with certain aspects of various exemplary embodiments of the present disclosure. [Figure 3A] 1 illustrates an example mapping between logical channels and transport channels in the downlink in accordance with some aspects of various exemplary embodiments of the present disclosure. [Figure 3B] 1 illustrates an example mapping between logical channels and transport channels in the uplink in accordance with some aspects of various exemplary embodiments of the present disclosure. [Figure 3C] 1 illustrates an example mapping between logical channels and transport channels in a sidelink in accordance with some aspects of various exemplary embodiments of the present disclosure. [Figure 4A] 1 illustrates an example mapping between transport channels and physical channels in the downlink in accordance with some aspects of various exemplary embodiments of the present disclosure. [Figure 4B] 1 illustrates an example mapping between transport channels and physical channels in the uplink in accordance with some aspects of various exemplary embodiments of the present disclosure. [Figure 4C] 1 illustrates an example mapping between transport channels and physical channels in a sidelink in accordance with some aspects of various exemplary embodiments of the present disclosure. [Figure 5A]1 illustrates an example radio protocol stack for NR sidelink communications in accordance with certain aspects of various exemplary embodiments of the present disclosure. [Figure 5B] 1 illustrates an example radio protocol stack for NR sidelink communications in accordance with certain aspects of various exemplary embodiments of the present disclosure. [Figure 5C] 1 illustrates an example radio protocol stack for NR sidelink communications in accordance with certain aspects of various exemplary embodiments of the present disclosure. [Figure 5D] 1 illustrates an example radio protocol stack for NR sidelink communications in accordance with certain aspects of various exemplary embodiments of the present disclosure. [Figure 6] 1 illustrates exemplary physical signals in the downlink, uplink, and sidelink in accordance with certain aspects of various exemplary embodiments of the present disclosure. [Figure 7] 1 illustrates examples of Radio Resource Control (RRC) states and transitions between different RRC states in accordance with certain aspects of various exemplary embodiments of the present disclosure. [Figure 8] 1 illustrates an example frame structure and physical resources in accordance with certain aspects of various example embodiments of the present disclosure. [Figure 9] 1 illustrates exemplary component carrier configurations in different carrier aggregation scenarios in accordance with some aspects of various exemplary embodiments of the present disclosure. [Figure 10] 1 illustrates exemplary bandwidth portion configurations and switching in accordance with certain aspects of various exemplary embodiments of the present disclosure. [Figure 11] 1 illustrates an exemplary four-step contention-based and contention-free random access process in accordance with certain aspects of various exemplary embodiments of the present disclosure. [Figure 12] 1 illustrates an exemplary two-step contention-based and contention-free random access process in accordance with some aspects of various exemplary embodiments of the present disclosure. [Figure 13]1 illustrates an exemplary time and frequency structure of a synchronization signal and a physical broadcast channel (PBCH) block (SSB) in accordance with certain aspects of various exemplary embodiments of the present disclosure. [Figure 14] 1 illustrates an exemplary SSB burst transmission in accordance with certain aspects of various exemplary embodiments of the present disclosure. [Figure 15] 1 illustrates exemplary components of a user equipment and a base station for transmission and / or reception in accordance with several aspects of various exemplary embodiments of the present disclosure. [Figure 16] 1 illustrates an example MBS group notification / paging for session initiation or MBS configuration change in accordance with certain aspects of various example embodiments of the present disclosure. [Figure 17] 1 illustrates an example short message indicator field of paging downlink control information in accordance with certain aspects of various example embodiments of the present disclosure. [Figure 18] 1 illustrates exemplary short message fields of paging downlink control information in accordance with certain aspects of various exemplary embodiments of the present disclosure. [Figure 19] 1 illustrates an exemplary extended short message field in a paging DCI in accordance with certain aspects of various exemplary embodiments of the present disclosure. [Figure 20] 1 illustrates an exemplary extended short message field in a paging DCI in accordance with certain aspects of various exemplary embodiments of the present disclosure. [Figure 21A] 1 illustrates an exemplary two-step transmission of MBS notification and MBS configuration / session update in accordance with certain aspects of various exemplary embodiments of the present disclosure. [Figure 21B] 1 illustrates an exemplary two-step transmission of MBS notification and MBS configuration / session update in accordance with certain aspects of various exemplary embodiments of the present disclosure. [Figure 22]1 illustrates an example RRC-SIB configuration table for MBS notification combinations in accordance with certain aspects of various example embodiments of the present disclosure. [Figure 23] 1 illustrates an exemplary process in accordance with several aspects of various exemplary embodiments of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0016] 1 illustrates an example of a mobile communication system 100 according to some aspects of various exemplary embodiments of the present disclosure. The mobile communication system 100 may be operated by a wireless communication system operator, such as a mobile network operator (MNO), a private network operator, a multi-system operator (MSO), an Internet of Things (IoT) network operator, etc., and may provide services such as voice, data (e.g., wireless Internet access), messaging, vehicular communication services such as vehicle-to-everything (V2X) communication services, safety services, mission-critical services, and services in residential, commercial, or industrial environments, such as IoT and Industrial IoT (IIOT).

[0017] The mobile communication system 100 may enable various types of applications with different requirements regarding latency, reliability, throughput, etc. Examples of supported applications include enhanced mobile broadband (eMBB), ultra-reliable low-latency communications (URLLC), and massive machine-type communications (mMTC). eMBB may support stable connections with high peak data rates and moderate rates for cell-edge users. URLLC may support applications with stringent requirements regarding latency and reliability, and moderate requirements regarding data rates. An exemplary mMTC application includes a network of many IoT devices that are only sporadically active and transmit small data payloads.

[0018] The mobile communication system 100 may include a radio access network (RAN) portion and a core network portion. The example shown in FIG. 1 illustrates a Next Generation RAN (NG-RAN) 105 and a 5G Core Network (5GC) 110 as examples of the RAN and core network, respectively. Other examples of the RAN and core network may be implemented without departing from the scope of the present disclosure. Other examples of the RAN include an evolved universal terrestrial radio access network (EUTRAN), a universal terrestrial radio access network (UTRAN), etc. Other examples of the core network include an evolved packet core (EPC), a UMTS core network (UCN), etc. The RAN implements a radio access technology (RAT) and resides between the user equipment (UE) 125 and the core network. Examples of such RATs include New Radio (NR), Long Term Evolution (LTE), also known as Evolved Universal Terrestrial Radio Access (EUTRA), Universal Mobile Telecommunications System (UMTS), etc. The RAT of the exemplary system 100 of mobile communication may be NR. The core network resides between the RAN and one or more external networks (e.g., data networks) and is responsible for functions such as mobility management, authentication, session management, bearer setup, and application of different Quality of Service (QoS). The functional layer between the UE 125 and the RAN (e.g., NG-RAN 105) is sometimes referred to as the Access Stratum (AS), and the functional layer between the UE 125 and the core network (e.g., 5GC 110) is sometimes referred to as the Non-Access Stratum (NAS).

[0019] The UE 125 may include wireless transmitting and receiving means for communicating with one or more nodes in a RAN, one or more relay nodes, or one or more other UEs, etc. Examples of UEs include, but are not limited to, smartphones, tablets, laptops, computers, wireless transmitting and / or receiving units in vehicles, V2X or vehicle-to-vehicle (V2V) devices, wireless sensors, IoT devices, IIOT devices, etc. Other names may be used for a UE, such as mobile station (MS), terminal equipment, terminal node, client device, mobile device, etc.

[0020] The RAN may include nodes (e.g., base stations) for communicating with UEs. For example, the NG-RAN 105 of the mobile communication system 100 may include nodes for communicating with the UE 125. For example, different names may be used for the RAN nodes depending on the RAT used for the RAN. A RAN node may be referred to as a Node B (NB) in a RAN using the UMTS RAT. A RAN node may be referred to as an Evolved Node B (eNB) in a RAN using the LTE / EUTRA RAT. In the illustrative example of the mobile communication system 100 in FIG. 1 , the nodes of the NG-RAN 105 may be either a Next Generation Node B (gNB) 115 or a Next Generation Evolved Node B (ng-eNB) 120. In this specification, the terms base station, RAN node, gNB, and ng-eNB may be used interchangeably. The gNB 115 may provide NR user plane and control plane protocol terminations for the UE 125. The ng-eNB 120 may provide E-UTRA user plane and control plane protocol terminations for the UE 125. The interface between the gNB 115 and the UE 125 or between the ng-eNB 120 and the UE 125 may be referred to as a Uu interface. The Uu interface may be established using a user plane protocol stack and a control plane protocol stack. For the Uu interface, the direction from the base station (e.g., the gNB 115 or the ng-eNB 120) to the UE 125 may be referred to as a downlink, and the direction from the UE 125 to the base station (e.g., the gNB 115 or the ng-eNB 120) may be referred to as an uplink.

[0021] The gNB 115 and the ng-eNB 120 may be interconnected using 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 GPRS Tunneling Protocol (GTP) may be used on User Datagram Protocol (UDP) / IP to carry user plane protocol data units (PDUs). Xn-U may provide non-guaranteed delivery of user plane PDUs and may support data forwarding and flow control. The transport network layer of the Xn-C interface may be built on Stream Control Transport Protocol (SCTP) over IP. The application layer signaling protocol may be referred to as XnAP (Xn Application Protocol). The SCTP layer may provide guaranteed delivery of application layer messages. At the transport IP layer, point-to-point transmission may be used to deliver signaling PDUs. The Xn-C interface may support Xn interface management, UE mobility management including context transfer and RAN paging, and dual connectivity.

[0022] The gNB 115 and ng-eNB 120 may also be connected to the 5GC 110 via an NG interface, more specifically to the Access and Mobility Management Function (AMF) 130 of the 5GC 110 via an NG-C interface, and to the User Plane Function (UPF) 135 of the 5GC 110 via an NG-U interface. The transport network layer of the NG-U interface may be built on IP transport, and the GTP protocol over UDP / IP may be used to carry user plane PDUs between the NG-RAN node (e.g., the gNB 115 or ng-eNB 120) and the UPF 135. The NG-U may provide non-guaranteed delivery of user plane PDUs between the NG-RAN 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 transmission of signaling messages. The application layer signaling protocol may be referred to as NGAP (NG Application Protocol). The SCTP layer may provide guaranteed delivery of application layer messages. For transport, IP layer point-to-point transmission may be used to deliver signaling PDUs. The NG-C interface may provide the following functions: NG interface management, UE context management, UE mobility management, NAS message transfer, paging, PDU session management, configuration transfer, and alert message transmission.

[0023] The gNB115 or ng-eNB120 may host one or more of the following functions: radio bearer control, radio admission control, connection mobility control, radio resource management functions such as dynamic allocation of resources (e.g., scheduling) to UEs in both uplink and downlink, IP and Ethernet header compression of data, encryption and integrity protection, selection of an AMF at UE attachment when routing to the AMF cannot be determined from information provided by the UE, routing of user plane data to the UPF, routing of control plane information to the AMF, connection setup and release, scheduling and transmission of paging messages, scheduling and transmission of system broadcast information (e.g., derived from the AMF), measurement and measurement reporting configuration for mobility and scheduling, transport level packet marking in the uplink, session management, support for network slicing, QoS flow management and mapping to data radio bearers, support for UEs in RRC inactive state, delivery functions for NAS messages, radio access network sharing, dual connectivity, close interaction between NR and E-UTRA, maintenance of security and radio configuration for user plane 5G System (5GS) Cellular IoT (CIoT) optimization.

[0024] The AMF 130 may host one or more of the following functions: NAS signaling termination, NAS signaling security, AS security control, CN inter-node signaling for mobility between 3GPP access networks, idle mode UE reachability (including control and execution of paging retransmissions), registration area management, support for intra-system and inter-system mobility, access authentication, access authorization including verification of roaming rights, mobility management control (subscription and policy), support for network slicing, Session Management Function (SMF) selection, 5GS CIoT optimization selection.

[0025] The UPF 135 may host one or more of the following functions: anchor point for intra / inter-RAT mobility (if applicable), external PDU session point of interconnection to the data network, packet routing and forwarding, packet inspection and user plane part of policy rule enforcement, traffic usage reporting, uplink classifier to support routing of traffic flows to the data network, branching point to support multi-homed PDU sessions, QoS processing for the user plane, e.g., packet filtering, gating, UL / DL rate enforcement, uplink traffic validation (Service Data Flow (SDF) to QoS flow mapping), downlink packet buffering and downlink data notification triggering.

[0026] As shown in FIG. 1, the NG-RAN 105 may support a PC5 interface between two UEs 125 (e.g., UE 125A and UE 125B). In the PC5 interface, the direction of communication between the two UEs (e.g., from UE 125A to UE 125B or vice versa) may be referred to as a sidelink. Sidelink transmission and reception over the PC5 interface may be supported when the UE 125 is within NG-RAN 105 coverage and when the UE is out of NG-RAN 105 coverage, regardless of which RRC state the UE 125 is in. Support for V2X services over the PC5 interface may be provided by NR sidelink communication and / or V2X sidelink communication.

[0027] PC5-S signaling may be used for unicast link establishment involving direct communication request / accept messages. A UE may self-assign a source Layer-2 ID for a PC5 unicast link, for example, based on the V2X service type. During the unicast link establishment procedure, a UE may transmit its source Layer-2 ID for the PC5 unicast link to a peer UE, e.g., a UE from which the destination ID was received from a higher layer. The source Layer-2 ID and destination Layer-2 ID pair may uniquely identify a unicast link. The receiving UE may verify that the destination ID belongs to it and accept the unicast link establishment request from the source UE. During the PC5 unicast link establishment procedure, a PC5-RRC procedure on the access stratum may be invoked for UE sidelink context establishment purposes, as well as for AS layer configuration, capability exchange, etc. PC5-RRC signaling may enable the exchange of AS layer configurations, such as UE capabilities and sidelink radio bearer configurations, between pairs of UEs between which a PC5 unicast link is established.

[0028] NR sidelink communication may support one of three types of transmission modes (e.g., unicast transmission, groupcast transmission, and broadcast transmission) for a pair of source Layer 2 ID and destination Layer 2 ID in an AS. The unicast transmission mode may be characterized by the following: support of one PC5-RRC connection between peer UEs for the pair, transmission and reception of control information and user traffic between peer UEs on the sidelink, support of sidelink HARQ feedback, support of sidelink transmit power control, support of RLC acknowledged mode (AM), and detection of radio link failure for the PC5-RRC connection. The groupcast transmission may be characterized by the following: transmission and reception of user traffic between UEs belonging to a group on the sidelink, and support of sidelink HARQ feedback. The broadcast transmission may be characterized by the following: transmission and reception of user traffic between UEs on the sidelink.

[0029] NR sidelink communications may use a source Layer-2 ID, a destination Layer-2 ID, and a PC5 link identifier. The source Layer-2 ID may be a link layer identifier that identifies the device or group of devices that is the recipient of the sidelink communication frame. The destination Layer-2 ID may be a link layer identifier that identifies the device that originates the sidelink communication frame. In some examples, the source Layer-2 ID and the destination Layer-2 ID may be assigned by a management function in the core network. The source Layer-2 ID may identify the source of data in NR sidelink communications. The source Layer-2 ID may be 24 bits long and may be split into two bit strings at the MAC layer. One bit string may be the least significant 8-bit portion of the source Layer-2 ID 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 packet filtering at the receiver's physical layer. The second bit string may be the most significant 16-bit portion of the source Layer-2 ID and may be carried in the medium access control (MAC) header. This may be used for packet filtering at the receiver's MAC layer. The destination Layer 2 ID may identify the target of data in NR sidelink communication. For NR sidelink communication, the destination Layer 2 ID may be 24 bits long and split into two bit strings at the MAC layer. One bit string may be the least significant byte (16 bits) of the destination Layer 2 ID and may be forwarded to the sender's physical layer. This may identify the intended target of the data in the sidelink control information and may be used for packet filtering at the receiver's physical layer. The second bit string may be the most significant byte (8 bits) of the destination Layer 2 ID and may be carried in the MAC header. This may be used for packet filtering at the receiver's MAC layer. The PC5 link identifier may uniquely identify a PC5 unicast link within a UE for the lifetime of the PC5 unicast link. The PC5 link identifier may be used to indicate the PC5 unicast link for which a sidelink radio link failure (RLF) declaration has occurred and the PC5-RRC connection has been released.

[0030] 2A and 2B illustrate example radio protocol stacks for the user plane and control plane, respectively, in accordance with certain aspects of various exemplary embodiments of the present disclosure. As shown in FIG. 2A, the protocol stack for the user plane of the Uu interface (between the UE 125 and the gNB 115) includes Service Data Adaptation Protocol (SDAP) 201 and SDAP 211, Packet Data Convergence Protocol (PDCP) 202 and PDCP 212, Radio Link Control (RLC) 203 and RLC 213, MAC 204 and MAC 214, and sublayers of Layer 2 and physical (PHY) 205 and PHY 215 layers (Layer 1 is also referred to as L1).

[0031] The PHY 205 and PHY 215 provide transport channels 244 to the MAC 204 and MAC 214 sublayers. The MAC 204 and MAC 214 sublayers provide logical channels 243 to the RLC 203 and RLC 213 sublayers. The RLC 203 and RLC 213 sublayers provide RLC channels 242 to the PDCP 202 and PDCP 212 sublayers. The PDCP 202 and PDCP 212 sublayers provide radio bearers 241 to the SDAP 201 and SDAP 211 sublayers. The radio bearers can be classified into two groups: data radio bearers (DRBs) for user plane data and signaling radio bearers (SRBs) for control plane data. The SDAP 201 and SDAP 211 sublayers provide QoS flows 240 to the 5GC.

[0032] The main services and functions of the MAC204 or MAC214 sublayer include mapping between logical channels and transport channels, multiplexing / demultiplexing of MAC service data units (SDUs) belonging to one or different logical channels to / from transport blocks (TBs) passed to / from the physical layer on transport channels, scheduling information reporting, error correction via Hybrid Automatic Repeat Request (HARQ) (one HARQ entity per cell in the case of carrier aggregation (CA)), priority handling between UEs via dynamic scheduling, priority handling between logical channels of one UE via Logical Channel Prioritization (LCP), priority handling between overlapping resources of one UE, and padding. A single MAC entity may support multiple numerologies, transmission timings, and cells. Mapping restrictions in logical channel prioritization control which numerologies, cells, and transmission timings a logical channel may use.

[0033] The HARQ function may ensure delivery between peer entities at Layer 1. If the physical layer is not configured for downlink / uplink spatial multiplexing, a single HARQ process may support one TB, and if the physical layer is configured for downlink / uplink spatial multiplexing, a single HARQ process may support one or more TBs.

[0034] The RLC203 or RLC213 sublayer may support three transmission modes: Transparent Mode (TM), Unacknowledged Mode (UM), and Acknowledged Mode (AM). The RLC configuration may be per logical channel independent of the numerology and / or transmission time, and Automatic Repeat Request (ARQ) may operate with any of the numerologies and / or transmission times for which the logical channel is configured.

[0035] The main services and functions of the RLC203 or RLC213 sublayer depend on the transmission mode (e.g., TM, UM, or AM) and may include: transfer of upper layer PDUs, sequence numbers independent of PDCP sequence numbers (UM and AM), error correction via ARQ (AM only), segmentation (AM and UM) and resegmentation (AM only) of RLC SDUs, reassembly of SDUs (AM and UM), duplicate detection (AM only), RLC SDU discard (AM and UM), RLC re-establishment, and protocol error detection (AM only).

[0036] An automatic repeat request in the RLC203 or RLC213 sublayer may have the following characteristics: ARQ retransmits an RLC SDU or an RLC SDU segment based on an RLC status report, polling for RLC status notification may be used if required by RLC, and the RLC receiver may also trigger an RLC status notification after detecting a missing RLC SDU or an RLC SDU segment.

[0037] The main services and functions of the PDCP202 or PDCP212 sublayer may include: forwarding of data (user plane or control plane), maintaining the PDCP sequence number (SN), header compression and decompression using the Robust Header Compression (ROHC) protocol, header compression and decompression using the EHC protocol, encryption and decryption, integrity protection and integrity verification, timer-based SDU discarding, split bearer routing, duplication, reordering and in-order delivery, out-of-order delivery, and duplicate discarding.

[0038] The main services and functions of the SDAP 201 or SDAP 211 may include the following: mapping between QoS flows and data radio bearers, and marking of QoS Flow IDs (QFIs) in both downlink and uplink packets. A single protocol entity of the SDAP may be configured for each individual PDU session.

[0039] As shown in FIG. 2B, the control plane protocol stack of the Uu interface (between UE 125 and gNB 115) includes the PHY layer (Layer 1), the MAC, RLC and PDCP sublayers of Layer 2, and further the RRC206 and RRC216 sublayers, as described above. The main services and functions of the RRC206 and RRC216 sublayers on the Uu interface are: broadcasting system information related to the AS and NAS; paging initiated by 5GC or NG-RAN; establishment, maintenance, and release of RRC connections between the UE and NG-RAN (including adding, modifying, and releasing carrier aggregation, and adding, modifying, and releasing dual connectivity between NR or E-UTRA and NR); security functions including key management; establishment, configuration, maintenance, and release of SRBs and DRBs; mobility functions (including handover and context transfer, UE cell selection and reselection and control of cell selection and reselection, and inter-RAT mobility); QoS management functions; UE measurement reporting and reporting control; radio link failure detection and recovery; and NAS message transfer between the UE and the NAS. The NAS207 and NAS227 layers are control protocols (terminated in the AMF on the network side) that perform functions such as authentication, mobility management, and security control.

[0040] Sidelink-specific services and functions of the RRC sublayer over the Uu interface may include: configuration of sidelink resource allocation via system information or dedicated signaling, reporting of UE sidelink information, sidelink-related measurement configuration and reporting, and reporting of UE assistance information for SL traffic patterns.

[0041] 3A, 3B, and 3C each illustrate an exemplary mapping between logical channels and transport channels in the downlink according to some aspects of various exemplary embodiments of the present disclosure. Different types of data transfer services may be provided by the MAC. Each logical channel type may be defined according to the type of information transferred. Logical channels may be classified into two groups: control channels and traffic channels. Control channels may be used only for the transfer of control plane information. The Broadcast Control Channel (BCCH) is a downlink channel for broadcasting system control information. The Paging Control Channel (PCCH) is a downlink channel that carries paging messages. The Common Control Channel (CCCH) is a channel for transmitting control information between a UE and a network. This channel may be used for UEs that do not have an RRC connection with the network. The Dedicated Control Channel (DCCH) is a point-to-point bidirectional channel that transmits dedicated control information between a UE and a network and may be used by UEs that have an RRC connection. Traffic channels may be used only for the transfer of user plane information. A dedicated traffic channel (DTCH) is a point-to-point channel dedicated to one UE for transferring user information. DTCHs can exist in both the uplink and downlink. 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. A sidelink traffic channel (STCH) is a sidelink channel for transmitting user information from one UE to another. A sidelink broadcast control channel (SBCCH) is a sidelink channel for broadcasting sidelink system information from one UE to other UEs.

[0042] Downlink transport channel types include a broadcast channel (BCH), a downlink shared channel (DL-SCH), and a paging channel (PCH). The BCH may be characterized by a fixed, predefined transport format, a requirement to be broadcast throughout the coverage area of ​​a cell, either as a single message or by beamforming different BCH instances. The DL-SCH may be characterized by support for HARQ, support for dynamic link adaptation by varying modulation, coding, and transmit power, the possibility of being broadcast throughout the cell, the possibility of using beamforming, support for both dynamic and semi-static resource allocation, and support for UE discontinuous reception (DRX) to enable UE power savings. The DL-SCH may be characterized by support for HARQ, support for dynamic link adaptation by varying modulation, coding, and transmit power, the possibility of being broadcast throughout the cell, the possibility of using beamforming, support for both dynamic and semi-static resource allocation, and support for UE discontinuous reception (DRX) to enable UE power savings. The PCH may be characterized by the following: support for UE discontinuous reception (DRX) to enable UE power saving (DRX cycle indicated to the UE by the network), the requirement that it be broadcast throughout the coverage area of ​​the cell either as a single message or by beamforming different PCH instances, and mapping to physical resources that can also be dynamically used for traffic / other control channels.

[0043] In the downlink, the following connections may exist between logical channels and transport channels: BCCH may be mapped to BCH, BCCH may be mapped to DL-SCH, PCCH may be mapped to PCH, CCCH may be mapped to DL-SCH, DCCH may be mapped to DL-SCH, and DTCH may be mapped to DL-SCH.

[0044] Uplink transport channel types include the Uplink Shared Channel (UL-SCH) and the Random Access Channel (RACH). The UL-SCH may be characterized by the following: the possibility of using beamforming, support for dynamic link adaptation by varying transmit power and potentially modulation and coding, support for HARQ, and support for both dynamic and quasi-static resource allocation. The RACH may be characterized by limited control information and collision risk.

[0045] In the uplink, the following connections may exist between logical channels and transport channels: CCCH may be mapped to UL-SCH, DCCH may be mapped to UL-SCH, and DTCH may be mapped to UL-SCH.

[0046] Sidelink transport channel types include a Sidelink Broadcast Channel (SL-BCH) and a Sidelink Shared Channel (SL-SCH). The SL-BCH may be characterized by a predefined transport format. The SL-SCH may be characterized by support for unicast, groupcast, and broadcast transmissions, support for both UE autonomous resource selection and scheduled resource allocation by the NG-RAN, support for both dynamic and quasi-static resource allocation when the UE is assigned resources by the NG-RAN, support for HARQ, and support for dynamic link adaptation by varying transmit power, modulation, and coding.

[0047] In the sidelink, the following connections may exist between logical channels and transport channels: SCCH may be mapped to SL-SCH, STCH may be mapped to SL-SCH, and SBCCH may be mapped to SL-BCH.

[0048] 4A, 4B, and 4C each illustrate an example mapping between transport channels and physical channels in the downlink in accordance with some aspects of various exemplary embodiments of the present disclosure. The physical channels in the downlink include a physical downlink shared channel (PDSCH), a physical downlink control channel (PDCCH), and a physical broadcast channel (PBCH). The PCH and DL-SCH transport channels are mapped to the PDSCH. The BCH transport channel is mapped to the PBCH. No transport channels are mapped to the PDCCH, and downlink control information (DCI) is transmitted via the PDCCH.

[0049] Physical channels in the uplink include the Physical Uplink Shared Channel (PUSCH), the Physical Uplink Control Channel (PUCCH), and the Physical Random Access Channel (PRACH). The UL-SCH transport channel may be mapped to the PUSCH, and the RACH transport channel may be mapped to the PRACH. The transport channels are not mapped to the PUCCH, and uplink control information (UCI) is transmitted via the PUCCH.

[0050] The sidelink physical channels include the Physical Sidelink Shared Channel (PSSCH), the Physical Sidelink Control Channel (PSCCH), the Physical Sidelink Feedback Channel (PSFCH), and the Physical Sidelink Broadcast Channel (PSBCH). The Physical Sidelink Control Channel (PSCCH) may indicate the resources and other transmission parameters used by the UE for the PSSCH. The Physical Sidelink Shared Channel (PSSCH) may transmit TBs of the data itself as well as control information such as HARQ procedures and CSI feedback triggers. At least six OFDM symbols in one slot may be used for PSSCH transmission. The Physical Sidelink Feedback Channel (PSFCH) may carry HARQ feedback over the sidelink from the UE that is the intended recipient of the PSSCH transmission to the UE that performed the transmission. The PSFCH sequence may be transmitted in one PRB repeated across two OFDM symbols near the edge of the sidelink resources in the slot. The SL-SCH transport channel may be mapped to the PSSCH. The SL-BCH may be mapped to the PSBCH. Transport channels are not mapped to the PSFCH, but sidelink feedback control information (SFCI) may be mapped to the PSFCH. Transport channels are not mapped to the PSCCH, but sidelink control information (SCI) may be mapped to the PSCCH.

[0051] Figures 5A, 5B, 5C, and 5D each illustrate an example of a radio protocol stack for NR sidelink communications according to some aspects of various exemplary embodiments of the present disclosure. The AS protocol stack for the user plane at the PC5 interface (i.e., for STCH) may consist of the SDAP, PDCP, RLC, and MAC sublayers, and a physical layer. The user plane protocol stack is shown in Figure 5A. The AS protocol stack for the SBCCH at the PC5 interface may consist of the RRC, RLC, MAC sublayers, and a physical layer, as shown below in Figure 5B. To support the PC5-S protocol, PC5-S is placed above the PDCP, RLC, and MAC sublayers, and a 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 at the PC5 interface consists of the RRC, PDCP, RLC, and MAC sublayers, and a physical layer. The control plane protocol stack for the SCCH for RRC is shown in Figure 5D.

[0052] 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 can be configured for PC5-RRC and PC5-S signaling, respectively.

[0053] The MAC sublayer may provide the following services and functions over the PC5 interface: radio resource selection, packet filtering, priority handling between uplink and sidelink transmissions for a given UE, and sidelink CSI reporting. Due to the restriction of logical channel prioritization in the MAC, only sidelink logical channels belonging to the same destination may be multiplexed into a MAC PDU for each unicast, groupcast, and broadcast transmission that may be associated with the destination. For packet filtering, an SL-SCH MAC header containing both the source Layer 2 ID and the destination Layer 2 ID portion may be added to the MAC PDU. The logical channel identifier (LCID) included in the MAC subheader may uniquely identify a logical channel within the combination of the source Layer 2 ID and the destination Layer 2 ID.

[0054] The services and functions of the RLC sublayer may be supported for the sidelink. Both RLC unacknowledged mode (UM) and acknowledged mode (AM) may be used for unicast transmission, while only UM may be used for groupcast or broadcast transmission. In the case of UM, only one-way transmission may be supported for groupcast and broadcast.

[0055] The services and functions of the PDCP sublayer for the Uu interface may be supported for the sidelink with some restrictions: out-of-order delivery may only be supported for unicast transmission, and duplication may not be supported over the PC5 interface.

[0056] The SDAP sublayer may provide the following services and functions over the PC5 interface: mapping between QoS flows and sidelink data radio bearers. There may be one SDAP entity per destination for one of unicast, groupcast, and broadcast associated with the destination.

[0057] The RRC sublayer may provide the following services and functions over the PC5 interface: transfer of PC5-RRC messages between peer UEs, maintenance and release of PC5-RRC connections between two UEs, and detection of sidelink radio link failure for PC5-RRC connections based on instructions from MAC or RLC. A PC5-RRC connection may be a logical connection between two UEs for a pair of source Layer 2 ID and destination Layer 2 ID that can be considered established after a corresponding PC5 unicast link is established. There may be a one-to-one correspondence between PC5-RRC connections and PC5 unicast links. A UE may have multiple PC5-RRC connections with one or more UEs for different pairs of source Layer 2 ID and destination Layer 2 ID. Separate PC5-RRC procedures and messages may be used by a UE to transfer UE capabilities and sidelink configurations, including SL-DRB configurations, to a peer UE. Both peer UEs may exchange their UE capabilities and sidelink configurations using separate bidirectional procedures in both sidelink directions.

[0058] FIG. 6 illustrates exemplary physical signals in the downlink, uplink, and sidelink according to some aspects of various exemplary embodiments of the present disclosure. Demodulation reference signals (DM-RSs) may be used in the downlink, uplink, and sidelink for channel estimation. DM-RSs are UE-specific reference signals that may be transmitted along with downlink, uplink, or sidelink physical channels for channel estimation and coherent detection of the physical channels. Phase tracking reference signals (PT-RSs) may be used in the downlink, uplink, and sidelink for phase tracking and mitigating performance loss due to phase noise. PT-RSs may be primarily used to estimate and minimize the impact of common phase error (CPE) on system performance. Due to phase noise characteristics, PT-RS signals may have low density in the frequency domain and high density in the time domain. PT-RSs may occur when configured with DM-RSs in a network. Positioning reference signals (PRSs) may be used in the downlink for positioning using different positioning techniques. The PRS may be used to measure downlink transmission delays by correlating received signals from the base station with a local replica in the receiver. The channel state information reference signal (CSI-RS) may be used in the downlink and sidelink. The CSI-RS may be used for, among other things, channel state estimation, reference signal received power (RSRP) measurements for mobility and beam management, and time / frequency tracking for demodulation. The CSI-RS may be configured UE-specific, but multiple users may share the same CSI-RS resource. The UE may determine CSI reports and transmit them to the base station in the uplink using the PUCCH or PUSCH. The CSI reports may be carried in the sidelink MAC CE. The primary synchronization signal (PSS) and secondary synchronization signal (SSS) may be used for radio frame synchronization. The PSS and SSS may be used for cell search procedures during initial attach or for mobility purposes.A sounding reference signal (SRS) may be used in the uplink for uplink channel estimation. Similar to CSI-RS, the SRS may serve as a QCL reference for other physical channels, such that they may be configured to be transmitted quasi-colocated with the SRS. Sidelink PSS (S-PSS) and sidelink SSS (S-SSS) may be used in the sidelink for sidelink synchronization.

[0059] 7 illustrates examples of radio resource control (RRC) states and transitions between different RRC states in accordance with certain aspects of various exemplary embodiments of the present disclosure. A UE may be in one of three RRC states: an RRC connected state 710, an RRC idle state 720, and an RRC inactive state 730. After power-on, the UE may be in the RRC idle state 720, and the UE may use initial access to establish a connection with the network via an RRC connection establishment procedure to perform data transfer and / or conduct a voice call. Once the RRC connection is established, the UE may enter the RRC connected state 710. The UE may transition from the RRC idle state 720 to the RRC connected state 710 or from the RRC connected state 710 to the RRC idle state 720 using an RRC connection establishment / release procedure 740.

[0060] 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 frequent small data. In the RRC inactive state 730, the AS context may be stored by both the UE and the gNB. This may result in a faster state transition from the RRC inactive state 730 to the RRC connected state 710. The UE may transition from the RRC inactive state 730 to the RRC connected state 710 or from the RRC connected state 710 to the RRC inactive state 730 using an RRC connection resume / deactivation procedure 760. The UE may transition from the RRC inactive state 730 to the RRC idle state 720 using an RRC connection release procedure 750.

[0061] FIG. 8 illustrates an example frame structure and physical resources according to some aspects of various exemplary embodiments of the present disclosure. Downlink, uplink, or sidelink transmissions may be organized into frames with a 10 ms duration consisting of ten 1 ms subframes. Each subframe may consist of 1, 2, 4, ... slots, and the number of slots per subframe may depend on the subcarrier spacing of the carrier on which the transmission occurs. The slot duration may be 14 symbols with a normal cyclic prefix (CP) or 12 symbols with an extended CP, and may scale in time as a function of the subcarrier spacing used so that there are an integer number of slots in a subframe. FIG. 8 illustrates a resource grid in the time and frequency domains. Each element of the resource grid, containing 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.

[0062] In some examples, with non-slot-based scheduling, packet transmission may occur over a portion of a slot, e.g., 2, 4, or 7 OFDM symbols, which may also be referred to as a minislot. Minislots may be used for low-latency applications such as URLLC and operation in unlicensed bands. In some embodiments, minislots may also be used for fast flexible scheduling of services (e.g., preemption of URLLC for eMBB).

[0063] FIG. 9 illustrates exemplary component carrier configurations in different carrier aggregation scenarios according to some aspects of various exemplary embodiments of the present disclosure. In carrier aggregation (CA), two or more component carriers (CCs) may be aggregated. A UE may simultaneously receive or transmit on one or more CCs depending on its capabilities. CA may be supported for both contiguous and non-contiguous CCs in the same band or different bands, as shown in FIG. 9. The gNB and UE may communicate using a serving cell. The serving cell may be associated with at least one downlink CC (e.g., may be associated with only one downlink CC or may be associated with a downlink CC and an uplink CC). The serving cell may be a primary cell (PCell) or a secondary cell (SCell).

[0064] The UE may 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 may determine a 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.

[0065] In the RRC connected state, the gNB may be responsible for maintaining the timing advance to keep L1 synchronized. Serving cells with uplinks to which the same timing advance applies and that use the same timing reference cell are grouped into a timing advance group (TAG). A TAG may contain at least one serving cell with a configured uplink. The mapping of serving cells to TAGs may be configured by RRC. For a primary TAG, the UE may use the PCell as the timing reference cell, except for shared spectrum channel access, where an SCell may also be used as the timing reference cell in some cases. For a secondary TAG, the UE may use any of the activated SCells of this TAG as the timing reference cell and may not change it unless necessary.

[0066] A timing advance update may be signaled by the gNB to the UE via a MAC CE command. Such a command may restart a TAG-specific timer that may indicate whether L1 can be synchronized; when the timer is running, L1 may be considered synchronized; otherwise, L1 may be considered unsynchronized (uplink transmissions may only occur on the PRACH in this case).

[0067] A UE with single timing advance capability for CA may simultaneously receive and / or transmit multiple CCs corresponding to multiple serving cells (multiple serving cells grouped into one TAG) that share the same timing advance. A UE with multiple timing advance capability for CA may simultaneously receive and / or transmit multiple CCs corresponding to multiple serving cells (multiple serving cells grouped into multiple TAGs) with different timing advances. NG-RAN may ensure that each TAG contains at least one serving cell. A non-CA-capable 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).

[0068] The multi-carrier characteristics of the physical layer in case of CA may be exposed to the MAC layer, and one HARQ entity may be required per serving cell. When CA is configured, the UE may have one RRC connection with the network. In RRC connection establishment / re-establishment / handover, one serving cell (e.g., PCell) may provide NAS mobility information. Depending on the UE capabilities, the SCell may be configured to form a set of serving cells together with the PCell. The set of serving cells configured for the UE may consist of one PCell and one or more SCells. Reconfiguration, addition, and deletion of SCells may be performed by RRC.

[0069] In a dual connectivity scenario, a UE may be configured with multiple cells including a Master Cell Group (MCG) for communicating with a master base station, a Secondary Cell Group (SCG) for communicating with a secondary base station, and two MAC entities, one for the MCG for communicating with the master base station and one for the SCG for communicating with the secondary base station.

[0070] FIG. 10 illustrates exemplary bandwidth portion configuration and switching according to some aspects of various exemplary embodiments of the present disclosure. A UE may be configured with one or more bandwidth portions (BWPs) 1010 in a given component carrier. In some examples, one of the one or more bandwidth portions may be activated at a time. The active bandwidth portion may define the UE's operating bandwidth within the cell's operating bandwidth. For initial access, an initial bandwidth portion 1020 determined from system information may be used until the UE's configuration within the cell is received. For example, in bandwidth adaptation (BA) via BWP switching 1040, the UE's reception and transmission bandwidths may not be as large as the cell's bandwidth and may be adjusted. For example, the widths may be sequenced to change (e.g., shrink during periods of low activity to save power). The locations may move in the frequency domain (e.g., to increase scheduling flexibility). The subcarrier spacings may be sequenced to change (e.g., enable different services). The first active BWP 1020 may be the active BWP upon RRC (re)configuration of the PCell or activation of the SCell.

[0071] For a downlink BWP or an uplink BWP in a set of downlink or uplink BWPs, the UE may be provided with the following configuration parameters, respectively: subcarrier spacing (SCS), cyclic prefix, common RBs and a number of consecutive RBs, an index within the set of downlink or uplink BWPs by the respective BWP-Id, a set of BWP common parameters and a set of BWP-specific parameters. A BWP may be associated with an OFDM numerology according to the subcarrier spacing and cyclic prefix configured for the BWP. For the serving cell, the UE may be provided with a default downlink BWP among the configured downlink BWPs. If the UE is not provided with a default downlink BWP, the default downlink BWP may be the initial downlink BWP.

[0072] A downlink BWP may be associated with a BWP inactivity timer. If a BWP inactivity timer associated with an active downlink BWP expires and a default downlink BWP is configured, the UE may perform a BWP switch to the default BWP. If a BWP inactivity timer associated with an active downlink BWP expires and a default downlink BWP is not configured, the UE may perform a BWP switch to an initial downlink BWP.

[0073] 11 illustrates an exemplary four-step contention-based and contention-free random access process according to certain aspects of various exemplary embodiments of the present disclosure. Figure 12 illustrates an exemplary two-step contention-based and contention-free random access process according to certain aspects of various exemplary embodiments of the present disclosure. The random access procedure may be triggered by several events, such as: initial access from an RRC idle state, an RRC connection re-establishment procedure, downlink or uplink data arrival during an RRC connected state when the uplink synchronization state is "unsynchronized," uplink data arrival during an RRC connected state when there are no PUCCH resources available for a scheduling request (SR), an SR failure, a request by RRC upon synchronization reconfiguration (e.g., handover), a transition from an RRC inactive state, establishing time alignment of a secondary TAG, a request for other system information (SI), beam failure recovery (BFR), and a consistent uplink listen-before-talk (LBT) failure on the PCell.

[0074] Two types of random access (RA) procedures may be supported: a four-step RA type with MSG1 and a two-step RA type with MSGA. Both types of RA procedures may support contention-based random access (CBRA) and contention-free random access (CFRA), as shown in Figures 11 and 12.

[0075] The UE may select the type of random access at the start of the random access procedure based on the network configuration. If CFRA resources are not configured, the RSRP threshold may be used by the UE to select between the 2-step RA type and the 4-step RA type. If CFRA resources for the 4-step RA type are configured, the UE may perform random access using the 4-step RA type. If CFRA resources for the 2-step RA type are configured, the UE may perform random access using the 2-step RA type.

[0076] MSG1 for the 4-step RA type may consist of a preamble on the PRACH. After transmitting MSG1, the UE may monitor for a response from the network within the configured window. For CFRA, a dedicated preamble for MSG1 transmission is allocated by the network, and upon receiving a random access response (RAR) from the network, the UE may terminate the random access procedure as shown in FIG. 11. For CBRA, upon receiving the random access response, the UE may transmit MSG3 using the uplink grant scheduled in the random access response and monitor contention resolution as shown in FIG. 11. If contention resolution is not successful after MSG3 (re)transmission, the UE may revert to MSG1 transmission.

[0077] The MSGA for the two-step RA type may include a preamble in the PRACH and a payload in the PUSCH. After the MSGA transmission, the UE may monitor a response from the network within a configured window. For CFRA, a dedicated preamble and PUSCH resources may be configured for MSGA transmission, and upon receiving a network response, the UE may terminate the random access procedure as shown in FIG. 12. For CBRA, if contention resolution is successful upon receiving a network response, the UE may terminate the random access procedure as shown in FIG. 12. On the other hand, if a fallback indication is received in MSGB, the UE may perform MSG3 transmission using the uplink grant scheduled in the fallback indication and monitor contention resolution. If contention resolution is not successful after MSG3 (re)transmission, the UE may revert to MSGA transmission.

[0078] FIG. 13 illustrates an exemplary time and frequency structure of a synchronization signal and physical broadcast channel (PBCH) block (SSB) according to some aspects of various exemplary embodiments of the present disclosure. An SS / PBCH block (SSB) may consist of a primary synchronization signal (PSS) and a secondary synchronization signal (SSS), each occupying one symbol and 127 subcarriers (e.g., subcarrier numbers 56 through 182 in FIG. 13), and a PBCH spanning three OFDM symbols and 240 subcarriers, with one symbol remaining unused for the SSS in the center, as shown in FIG. 13. The possible time locations of the SSBs within a half-frame may be determined by the subcarrier spacing, and the periodicity of the half-frames in which the SSBs are transmitted may be configured by the network. During a half-frame, different SSBs may be transmitted in different spatial directions (i.e., using different beams spanning the cell's coverage area).

[0079] The PBCH may be used to carry the Master Information Block (MIB), which is used by the UE during cell search and initial access procedures. The UE may first decode the PBCH / MIB to receive other system information. The MIB may provide the UE with the parameters necessary to acquire System Information Block 1 (SIB1), more specifically, the information necessary to monitor the PDCCH for scheduling the PDSCH carrying SIB1. Additionally, the MIB may indicate cell barring status information. The MIB and SIB1 are 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 SI may be broadcast periodically on the DL-SCH, may be broadcast on demand on the DL-SCH (e.g., upon request from a UE in RRC idle, RRC inactive, or RRC connected state), or may be sent in a dedicated manner to UEs in RRC connected state on the DL-SCH (e.g., upon request, if configured by the network, from a UE in RRC connected state, or if the UE has an active BWP for which a common search space is not configured).

[0080] FIG. 14 illustrates an exemplary SSB burst transmission according to some aspects of various exemplary embodiments of the present disclosure. An SSB burst may include N SSBs, where each SSB of the N SSBs may correspond to a beam. The SSB burst may be transmitted according to a periodicity (e.g., an SSB burst duration). During a contention-based random access process, a UE may perform a random access resource selection process. Here, the UE first selects an SSB before selecting an RA preamble. The UE may select an SSB with an RSRP above a configured threshold. In some embodiments, the UE may select any SSB if an SSB with an RSRP above a configured threshold is not available. A set of random access preambles may be associated with the SSB. After selecting 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.

[0081] In some embodiments, a beam among the N beams may be associated with a CSI-RS resource. The UE may measure the CSI-RS resource and select a CSI-RS with an RSRP above a configured threshold. The UE may 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 may select a random access preamble corresponding to an SSB quasi-co-located with the selected CSI-RS.

[0082] 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 may use the indicated TCI state for reception of downlink control information (e.g., via the PDCCH) or data (e.g., via the PDSCH). The UE may use the indicated TCI state to use an appropriate beam for reception of data or control information. The indication of the TCI state may use an RRC configuration or a combination of RRC signaling and dynamic signaling (e.g., via a MAC Control Element (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-co-location (QCL) relationship between a downlink reference signal, such as a CSI-RS, and a DM-RS associated with a downlink control or data channel (e.g., the PDCCH or PDSCH, respectively).

[0083] In some embodiments, a UE may be configured with a list of up to M TCI-state configurations using physical downlink shared channel (PDSCH) configuration parameters to decode a PDSCH according to a detected PDCCH with DCI for the UE and a given serving cell, where M may depend on UE capabilities. Each TCI-state may include parameters for configuring a QCL relationship between one or two downlink reference signals and a DM-RS port of a PDSCH, a DM-RS port of a PDCCH, or a CSI-RS port of a CSI-RS resource. The quasi-co-location relationship may be configured by one or more RRC parameters. The quasi-co-location type corresponding to each DL RS may take one of the following values: "QCL-TypeA": {Doppler shift, Doppler spread, average delay, delay spread}, "QCL-TypeB": {Doppler shift, Doppler spread}, "QCL-TypeC": {Doppler shift, average delay}, "QCL-TypeD": {Spatial Rx parameters}. The UE may receive an activation command (eg, MAC CE) used to map the TCI state to a codepoint in the DCI field.

[0084] FIG. 15 illustrates exemplary components of a user equipment and a base station for transmission and / or reception according to some aspects of various exemplary embodiments of the present disclosure. All or a subset of the blocks and functions in FIG. 15 may reside in or be performed by the base station 1505 and the user equipment 1500. The antenna 1510 may be used to transmit or receive electromagnetic signals. The antenna 1510 may comprise one or more antenna elements and may enable different input / output antenna configurations, including a multiple-input multiple-output (MIMO) configuration, a multiple-input single-output (MISO) configuration, and a single-input multiple-output (SIMO) configuration. In some embodiments, the antenna 1510 may enable a massive MIMO configuration with tens or hundreds of antenna elements. The antenna 1510 may enable other multi-antenna techniques, such as beamforming. In some examples, depending on the capabilities of the UE 1500 or the type of the UE 1500 (e.g., a low-complexity UE), the UE 1500 may support only a single antenna.

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

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

[0087] The processor 1540 may include a hardware device having processing capabilities (e.g., a general-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, an FPGA, a programmable logic device, a discrete gate or transistor logic component, a discrete hardware component, or any combination thereof). In some examples, the processor 1540 may be configured to operate a 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 a memory (e.g., the memory 1530) to cause the UE 1500 or the base station 1505 to perform various functions.

[0088] Central processing unit (CPU) 1550 may perform basic arithmetic, logic, control, and input / output (I / O) operations specified by computer instructions in memory 1530. User equipment 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. GPU 1560 is dedicated circuitry for rapid manipulation and modification of memory 1530 to accelerate processing performance of user equipment 1500 and / or base station 1505. GPS 1570 may be used to enable location-based services or other services, for example, based on the geographic location of user equipment 1500.

[0089] In some examples, the UE may use discontinuous reception (DRX) in the RRC_IDLE and RRC_INACTIVE states to reduce power consumption. The UE may monitor one paging occasion (PO) per DRX cycle. A PO may be a set of PDCCH monitoring opportunities and may include multiple time slots (e.g., subframes or OFDM symbols) in which paging DCI may be transmitted. One paging frame (PF) may be one radio frame and may include one or more POs or the start of a PO.

[0090] In some examples, in multi-beam operation, the UE may assume that the same paging message and the same short message may be repeated in the transmission beam. The selection of the beam for receiving the paging message and the short message may be up to the UE implementation. The paging message may be the same for both RAN-initiated and CN-initiated paging.

[0091] In some examples, the UE may initiate an RRC connection resumption procedure upon receiving a paging initiated by the RAN. If the UE receives a CN-initiated paging in the RRC_INACTIVE state, the UE may move to RRC_IDLE and notify the NAS.

[0092] In some examples, the PF and PO for paging may be determined by the following formulas: The SFN for the PF is determined by: (SFN+PF_offset) mod T=(T div N)*(UE_ID mod N), and the index (i_s) indicating the index of the PO is determined by: i_s=floor(UE_ID / N) mod Ns.

[0093] In some examples, the PDCCH monitoring occasion for paging may be determined according to pagingSearchSpace and firstPDCCH-MonitoringOccasionOfPO and nrofPDCCH-MonitoringOccasionPerSSB-InPO, if configured. If SearchSpaceId=0 is configured for pagingSearchSpace, the PDCCH monitoring occasion for paging may be the same as for RMSI.

[0094] In some examples, when SearchSpaceId=0 is configured for pagingSearchSpace, Ns can be either 1 or 2. When Ns=1, there can be only one PO starting from the first PDCCH monitoring opportunity for paging in the PF. When Ns=2, the PO can be in either the first frame (i_s=0) or the second frame (i_s=1) of the PF.

[0095] In some examples, if a SearchSpaceId other than 0 is configured for pagingSearchSpace, the UE may monitor the (i_s+1)th PO. PO may be a set of "S*X" consecutive PDCCH monitoring opportunities, where "S" is the number of actual transmitted SSBs determined according to ssb-PositionsInBurst in SIB1, and X may be nrofPDCCH-MonitoringOccasionPerSSB-InPO, if configured, or may be equal to 1 otherwise. The [x*S+K]th PDCCH monitoring opportunity for paging in PO may correspond to the Kth transmitted SSB, where x=0, 1, ..., X-1, K=1, 2, ..., S. PDCCH monitoring opportunities for paging that do not overlap with UL symbols (determined according to tdd-UL-DL-ConfigurationCommon) may be numbered sequentially from 0, starting from the first PDCCH monitoring opportunity for paging in PF. If the first PDCCH-MonitoringOccasionOfPO exists, the starting PDCCH monitoring opportunity number for the (i_s+1)th PO is the (i_s+1)th value of the first PDCCH-MonitoringOccasionOfPO parameter, otherwise it may be equal to i_s*S*X. If X>1, once the UE detects a PDCCH transmission addressed to the P-RNTI in that PO, the UE may not need to monitor subsequent PDCCH monitoring occasions for this PO.

[0096] In some examples, a PO associated with a PF may start within or after the PF. In some examples, a PDCCH monitoring opportunity for a PO may span multiple radio frames. If a SearchSpaceId other than 0 is configured for the paging-SearchSpace, a PDCCH monitoring opportunity for a PO may span multiple periods of the paging search space.

[0097] In some examples, the following parameters are used in the calculation of the above PF and i_s: T: UE DRX cycle (T may be determined by the shortest UE-specific DRX value, if configured by RRC and / or higher layers, and the default DRX value broadcast in the system information. In RRC_IDLE state, if UE-specific DRX is not configured by higher layers, the default value is applied); N: T total number of paging frames; Ns: number of paging occasions in PF; PF_offset: offset used for PF determination; UE_ID: 5G-S-TMSI mod 1024.

[0098] In some examples, the parameters Ns, nAndPagingFrameOffset, nrofPDCCH-MonitoringOccasionPerSSB-InPO, and the length of the default DRX cycle may be signaled in SIB1. The values ​​of N and PF_offset may be derived from the parameter nAndPagingFrameOffset. In some examples, the parameter first-PDCCH-MonitoringOccasionOfPO may be signaled in SIB1 for paging in an initial DL BWP. For paging in a DL BWP other than the initial DL BWP, the parameter first-PDCCH-MonitoringOccasionOfPO may be signaled in the corresponding BWP configuration.

[0099] In some examples, if the UE does not have 5G-S-TMSI, for example, if the UE is not yet registered with the network, the UE may use a default identity UE_ID=0 in the above PF and i_s formulas.

[0100] In some examples, the 5G-S-TMSI may be a bit string 48 bits long. The 5G-S-TMSI may be interpreted as a binary number in the above formula, with the left-most bit representing the most significant bit.

[0101] In some examples, paging may enable the network to reach UEs in RRC_IDLE and RRC_INACTIVE states via paging messages and to notify UEs in RRC_IDLE, RRC_INACTIVE, and RRC_CONNECTED states of system information changes and ETWS / CMAS indications via short messages. Both paging messages and short messages may be addressed by P-RNTI on the PDCCH, but the former may be transmitted on the PCCH, while the latter may be transmitted directly on the PDCCH.

[0102] In some examples, in RRC_IDLE, the UE may monitor the paging channel for paging initiated by the CN. In RRC_INACTIVE, the UE may also monitor the paging channel for RAN-initiated paging. The UE may not need to continuously monitor the paging channel. Paging DRX may be defined when a UE in RRC_IDLE or RRC_INACTIVE may be required to monitor the paging channel for one paging occurrence (PO) per DRX cycle. The paging DRX cycle may be configured by the network. 1) For CN initiated paging, a default cycle may be broadcast in the system information; 2) for CN initiated paging, a UE specific cycle may be configured by NAS signaling; 3) for RAN initiated paging, a UE specific cycle may be configured by RRC signaling, and the UE may use the shortest of the applicable DRX cycles, e.g., a UE in RRC_IDLE may use the shortest of the first two cycles above, and a UE in RRC_INACTIVE may use the shortest of the three.

[0103] In some examples, the UE's POs for CN-initiated paging and RAN-initiated paging may be based on the same UE ID, resulting in overlapping POs for both. The number of different POs in a DRX cycle is configurable via system information, and the network may distribute UEs to those POs based on their IDs.

[0104] In some examples, when RRC_CONNECTED, the UE may monitor the paging channel in the PO signaled in the system information for SI change indication and PWS notification. In the case of bandwidth adaptation (BA), the UE in RRC_CONNECTED may monitor the paging channel on the active BWP where the common search space is configured.

[0105] In some examples, for operation with shared spectrum channel access, a UE may be configured for an additional number of PDCCH monitoring opportunities in its PO to monitor paging. However, if the UE detects a PDCCH transmission in the PO of the UE addressed by the P-RNTI, the UE may not need to monitor subsequent PDCCH monitoring opportunities in this PO.

[0106] In some examples, the network may initiate a paging procedure by sending a paging message at a paging occasion of the UE. The network may address multiple UEs in the paging message by including one PagingRecord for each UE.

[0107] In some examples, upon receiving a paging message, when in RRC_IDLE, for each PagingRecord, if any, included in the paging message, the UE may forward the UE-Identity and accessType (if present) to higher layers if the UE-Identity included in the PagingRecord matches a UE identity assigned by higher layers.

[0108] In some examples, for RRC_INACTIVE, if there are Paging Records included in the paging message, for each Paging Record, the UE-Identity included in the Paging Record may match the UE's stored fullI-RNTI. If the UE is configured by higher layers with Access Identity 1, the UE may initiate the RRC connection resumption procedure with resumeCause set to mps-PriorityAccess. If the UE is configured by higher layers with Access Identity 2, the UE may initiate the RRC connection resumption procedure with resumeCause set to mcs-PriorityAccess. If the UE is configured by higher layers with one or more access identifiers equal to 11 through 15, the UE may initiate the RRC connection resumption procedure with resumeCause set to highPriorityAccess. Otherwise, the UE may initiate the RRC connection resumption procedure with resumeCause set to mt-Access.

[0109] In some examples, a short message may be transmitted on the PDCCH using the P-RNTI, with or without an associated paging message, using the short message field of DCI format 1_0. An example of a short message is shown in Figure 18. Bit 1 may be the most significant bit.

[0110] The exemplary embodiment enhances the counting of MBS group notifications and feedback from receiving UEs.

[0111] MBS data sessions can have a wide range of durations and transmission periods. In some examples, some UEs may receive MBS data without much unicast traffic and signaling during an MBS session. Power saving optimization for UEs with MBS sessions can be important because the UEs can receive 5G MBS in all RRC states.

[0112] In this disclosure, MBS configuration may be used to refer to MBS radio bearer and control configurations, e.g., MBS QoS, MCCH / MTCH configuration, SPS configuration, etc. MBS notification may be signaling that informs UEs about upcoming detailed MBS session / configuration changes or updates. In some examples, for both multicast and broadcast distribution modes, the network may support group-based notification to inform UEs about MBS session activation / deactivation, start / end, and MBS configuration changes before and during a session. Exemplary MBS group notification / paging for session start or MBS configuration change is shown in FIG. 16.

[0113] In some examples, for effective delivery of MBS data, the network may determine whether there are UEs receiving the data within the coverage area of ​​each base station and beam in the case of beamforming. In some examples, to ensure appropriate power saving for UEs receiving MBS data, the network may notify the UE of any changes to the MBS session and MBS configuration before and after the start of the MBS session.

[0114] In some examples, for broadcast services that a UE may receive in all RCC states, the RAN may not know the number of users receiving or interested in receiving MBS data. A framework for polling may be used to evaluate interest in MBS services and determine by the RAN. Polling may use group paging messages for a given MBS service group. In some examples, for multicast services, the RAN may keep track of users in a multicast group that are in an RRC connected state and / or have transitioned to an inactive state.

[0115] In some examples, MBSs requiring group notification may be sent for MBS change notification. In some examples, broadcast service continuity may require some form of counting and interest indication from the UE.

[0116] In some examples, at least for broadcast services, system information (SIB) messaging may be used to provide MBS control configuration and MCCH-type messaging may be used to provide MBS scheduling information. In some examples, PCCH-based notifications may be used for system information updates that the UE keeps track of across all RRC states.

[0117] In some examples, the MBS session may start later than when service availability is announced. In some examples, the start of the session may be known and provided to the UE by higher layer signaling upon service or group subscription. In some examples, the start time may be determined closer to data availability, in which case the UE may be notified of the MBS session start.

[0118] In some examples, once an MBS session has begun, the MBS configuration may change due to various reasons, such as changes in MCS, periodicity, user distribution or traffic patterns, etc. UEs may be notified in advance of such impending changes via group notification before they take effect.

[0119] In some examples, the network may poll users within its coverage area to see if any are interested in receiving MBS services. The network may have an assessment of their presence and number to configure its transmissions across cells and beams accordingly if beamforming is used. The trigger for such UE feedback for counting may use group notification.

[0120] In some examples, the framework may be used for group MBS notification to enable the following functionality: A.MBS system information update B. MBS session start / activate or stop / deactivate C. MBS configuration changes before or during an active session D. MBS count order to request interest indication from UE

[0121] Exemplary embodiments may structure the above information to fit into existing control signaling, allowing for configuring and transmitting uplink feedback and sending notifications to reach the UE.

[0122] In some examples, the number of UEs in an MBS group may be large and the MBS notification information may be common to all member UEs. UE-specific signaling may not be scalable or efficient in most cases.

[0123] In some examples, paging-based notification may be used to deliver such MBS notifications to UEs in all RRC states. UEs in RRC connected, inactive, and idle states may monitor paging occasions to obtain this notification information. MBS notifications reach UEs in all states and may be used by the core network or RAN to provide notifications regarding session start / end or MBS configuration changes.

[0124] In some examples, the common MBS notification framework may use the paging notification function of the PCCH using DCI addressed by the P-RNTI, or may use separate common notification messaging using, for example, the MBS-RNTI.

[0125] In some examples, unnecessary monitoring and processing of notification signaling by UEs that are not interested in the (target) MBS service may be avoided. In some examples, common notification signaling may be designed to avoid any impact on power savings for UEs that are not interested in the MBS service. In some examples, common notification signaling may be designed to target a specific MBS service to avoid adversely impacting power savings for MBS UEs that receive other MBS service groups.

[0126] In some examples, a PDCCH DCI format 1_0 with a CRC scrambled by the P_RNTI may be used to schedule paging messages. The DCI may include a short message indicator-2 bit, as shown in FIG.

[0127] In some examples, a short message may be transmitted on the PDCCH using the P-RNTI with or without an associated paging message using the short message field of DCI format 1_0. An example short message field of a paging DCI is shown in FIG. 18.

[0128] In some examples, the UE may react to notifications related to systemInfoModification or etwsAndCmasIndication sent as short message fields in the paging DCI and process applicable SIB messages. In some examples, in the case of MBS, SIB updates may be non-fictional and only UEs interested in the MBS may react and process SIB messages.

[0129] In some examples, the MBS SIB update may use one of the reserved bits in the short message field of the paging notification DCI separate from the systemInfoModification or etwsAndCmasIndication and may be ignored by UEs that are not interested in the MBS.

[0130] In some examples, detailed information about MBS notifications and MBS updates may be provided in two steps: the first step may be sent as a short message field in a notification DCI indicating that there are updates to some MBS sessions, and the second step provides information about the MBS sessions or configuration updates / changes.

[0131] In some examples, the MBS notification itself may be designed to target a specific MBS group or service and may distinguish between broadcast and multicast services. In some examples, it may be flexible to include triggers for various types of uplink feedback / responses from the UE. Based on the required functionality, at least some information may be included in the notification: notification type (e.g., A, B, or C above), target MBS service type (e.g., broadcast or multicast), target MBS service / group ID (MBS paging ID, TMGI, etc.), and uplink feedback / response (e.g., trigger to use and resource need).

[0132] In some examples, in a first step, the following options may be considered for sending a short notification:

[0133] An example embodiment for sending short notifications may be based on one of the reserved bits in the short message field of the notification DCI using the P-RNTI to flag any MBS session updates and provide the UE with MBS notification type and information details of any MBS service as an IE in a paging message on the PDSCH. An example of the extended short message field in the paging DCI is shown in Figure 19.

[0134] In some examples, the combination of notification information may be RRC pre-configured, may use a small number of reserved bits in the paging notification message (e.g., 5 reserved bits), or may be included as an extension to the paging information element message, or may be provided following the paging in another common control signaling message indicated by the paging.

[0135] In an exemplary embodiment, the N reserved bits in the short message field DCI masked by the PRNTI may be used to point to rows in a table preconfigured by the network to indicate different combinations of notification type and target MBS service, while indicating the remaining MBS notification information of the target MBS service as IEs in the paging message on the PDSCH. An example of an extended short message field in a paging DCI is shown in Figure 20.

[0136] In some examples, only UEs interested in a particular target MBS service / group may process the updated information, and other UEs with other MBS services may skip additional unnecessary paging message processing, saving power.

[0137] An example of two-step transmission of MBS notification and MBS configuration / session update is shown in Figures 21A and 21B. An example RRC-SIB configuration table for combined MBS notification is shown in Figure 22.

[0138] In some examples, a hybrid of the above approaches may be used to configure a combination of MBS notifications and send an index to row number in the paging message IE.

[0139] In some examples, a PDCCH with an MBS-specific MBS-N-RNTI may be used, and all bits in the short message field similar to the paging notification may be used to indicate different combinations.

[0140] In some examples, an uplink channel such as a RACH may be used to respond to notifications that may require UL feedback for network-triggered MBS count notifications. Exemplary embodiments may enable selective count triggering and UE feedback based on MBS services of selected distributed units or beams within a gNB.

[0141] In some examples, the RAN may selectively trigger counting of some or all MBS services within its coverage area. The RACH resource set associated with each MBS service group may be configured via the MBS SIB or as part of MBS notification signaling.

[0142] In some examples, the RACH resources may be further divided to provide the network with MBS counts applicable to different DUs / beams.

[0143] In some examples, the MBS notification for counting triggers the UE transmission on a set of RACH resources that may be identified in the MBS notification in the MBS Update IE in the paging message or as pre-configured by RRC.

[0144] In some examples, it may not be necessary for all UEs to send a counting response on the RACH, as the full count is not critical for MBS transmission decisions and modifications and may cause unnecessary uplink signaling congestion.

[0145] In some examples, transmissions on the RACH for counting by the UE may be restricted based on specific rules by the network, such as randomization seeds and probability calculations.

[0146] For example, notification signaling may be required for MBS services for MBS-related system information updates, triggers for counting and interest indications, configuration changes before and during an MBS session, etc. Existing mechanisms do not provide efficient signaling to achieve one or more notification objectives. Exemplary embodiments provide a framework and enhance existing signaling mechanisms to achieve efficient MBS-related notifications.

[0147] In the exemplary embodiment shown in FIG. 23, the UE may receive downlink control information (DCI) via a physical downlink control channel (PDCCH) based on monitoring the downlink control channel at the first monitoring time. In some examples, the UE may be in an RRC connected state. In some examples, the UE may be in an RRC idle / inactive state. The UE may perform a DRX procedure (e.g., a DRX procedure configured for an RRC connected state or a DRX procedure configured for an RRC inactive / idle state) to determine multiple monitoring opportunities, including the first monitoring opportunity, for control channel monitoring. For example, the UE may monitor for control channels in one or more search spaces / CORESETs associated with paging and / or MBS. In one example, the DCI may be associated with paging. For example, the DCI may be used to transmit scheduling information for a transport block received over a paging channel, and the transport block may include paging information. In one example, the DCI may be used to transmit a short message. In one example, the DCI may have a first format associated with paging.

[0148] The DCI may be associated with a first RNTI. In some examples, the DCI may be a paging DCI, and the first RNTI may be a paging RNTI. In some examples, the first RNTI may be an MBS RNTI. In some examples, the first RNTI may depend on whether the UE is in an RRC connected state or an RRC idle / inactive state.

[0149] The DCI may have multiple fields, including a first field and a second field. The first field may be a short message indicator field comprising multiple bits (e.g., 2 bits). A first value (e.g., 01) of the short message indicator field may indicate the presence of scheduling information for paging in the DCI (i.e., scheduling information for receiving a paging TB via a paging channel, the scheduling information including the paging information). A second value (e.g., 10) of the short message indicator field may indicate the presence of a short message in the DCI. A third value of the short message indicator field may indicate the presence of both a short message and scheduling information for paging in the DCI.

[0150] The first (short message indicator) field of the DCI may have a second or third value indicating that a short message is present in the DCI. The short message may be transmitted based on the second field in the DCI. The second field may include multiple bits. One or more of the multiple bits in the second field may indicate an update or change to one or more MBS-related parameters, for example, one or more configuration parameters for MBS data reception (e.g., SPS configuration parameters, etc.), and / or may indicate an update or change to system information associated with the MBS, and / or other changes or modifications.

[0151] The MBS notification indicated by the DCI indicates one or more of the following: notification type (e.g., one or more of MBS system information update / change, MBS session start / activation or stop / deactivation, MBS configuration change before or during an MBS session, MBS count order to trigger an MBS interest indication from the UE, etc.), target MBS service type (e.g., broadcast, multicast, etc.), target MBS service / group ID (e.g., MBS paging ID, TMGI, etc.), uplink feedback / response (e.g., trigger and need for resources to be used).

[0152] In some examples, the multiple bits of the short message field may include a flag (e.g., including a 1 bit) indicating the presence (e.g., based on a first value (e.g., 1) of the flag field) or absence (e.g., based on a second value (e.g., 0) of the flag field) of an MBS notification. In some examples, the flag field may be ignored by non-MBS UEs (e.g., UEs that are not interested in MBS service). In some examples, the multiple bits of the short message field may include one or more second bits indicating a BCCH change. In some examples, the multiple bits of the short message field may include one or more third bits indicating an Earthquake and Tsunami Warning System (ETWS) notification or a Commercial Mobile Alert System (CMAS) notification. In some examples, the multiple bits of the short message field may include one or more fourth bits indicating an update or change to the MBS SIB message. The MBS SIB may indicate, for example, a random access resource / preamble / opportunity. In some examples, the random access resource / preamble / opportunity may be beam-specific or distributed unit (DU)-specific. Random access resources / preambles / opportunities may be divided based on their association with beams / DUs. The random access resources / preambles / opportunities may be used for transmission of MBS interest indication signaling (e.g., using a random access message such as preamble / MsgA or Msg3). In some examples, the MBS notification may include an IE indicating a trigger for transmission of MBS interest signaling by an interested / MBS UE. A UE may transmit an MBS interest indication if the UE is interested in receiving MBS data or if the UE is an MBS UE. In some examples, the transmission of the MBS interest indication signaling may be based on a randomization seed or probability (e.g., a preconfigured or configurable randomization seed or probability). In some examples, some bits of the multiple bits of the short message field may be reserved.In some examples, bits of the short message may be mapped to a pre-configured or configurable (e.g., based on RRC signaling in an RRC connected state, or based on broadcast system information, e.g., about an RRC idle or inactive state) combination of changes or variations in MBS-related parameters. In some examples, bits of the short message field may be ignored by non-MBS UEs.

[0153] The UE may determine and / or search for signaling associated with the one or more MBS-related parameters that have been changed / updated based on the one or more bits of the short message field upon receipt (e.g., including and / or indicating the following): For example, the UE may receive MBS data based on the UE's interest in an MBS session corresponding to the one or more MBS-related parameters and based on receiving the DCI and one or more bits of the short message field.

[0154] In an exemplary embodiment, a user equipment (UE) may receive downlink control information (DCI). The DCI may be associated with at least a first radio network temporary identifier (RNTI) corresponding to an MBS-related notification. The DCI may include a first field and a second field. The first field may indicate that a short message is present in the DCI. The second field may be associated with the short message and may include a plurality of bits. One or more bits of the plurality of bits may indicate an update or change to one or more MBS-related parameters. The UE may determine to monitor signaling indicating updated or changed MBS-related parameters based on the indication by the one or more bits. The UE may receive MBS data based on the updated or changed MBS-related parameters.

[0155] In some examples, receiving downlink control information (DCI) may be based on a physical downlink control channel (PDCCH).

[0156] In some examples, receiving downlink control information (DCI) may be while the user equipment (UE) is in a radio resource control (RRC) connected state.

[0157] In some examples, receiving the downlink control information (DCI) may be while the user equipment (UE) is in a radio resource control (RRC) idle state or an RRC inactive state. In some examples, receiving the downlink control information (DCI) may be based on monitoring a downlink control channel at a monitoring occasion determined based on a discontinuous reception (DRX) procedure in the radio resource control (RRC) idle state or an RRC inactive state.

[0158] In some examples, the first radio network temporary identifier (RNTI) may be a paging RNTI. Downlink control information (DCI) may be associated with the transmission of the paging information.

[0159] In some examples, the first Radio Network Temporary Identifier (RNTI) may be a Multicast Broadcast Service (MBS)-RNTI.

[0160] In some examples, the first field may include one or more first bits having a first value. The first value may indicate that a short message is present in the downlink control information (DCI). In some examples, a second value of the one or more first bits may indicate that only scheduling information for paging is present in the downlink control information (DCI). In some examples, a third value of the one or more first bits may indicate that both scheduling information for paging and a short message are present in the downlink control information (DCI). In some examples, the scheduling information may indicate parameters for receiving a transport block including paging information via a paging channel.

[0161] In some examples, one or more second bits of the plurality of bits may indicate a broadcast control channel (BCCH) change.

[0162] In some examples, one or more third bits of the plurality of bits may indicate an Earthquake and Tsunami Warning System (EWTS) notification or a Commercial Mobile Alert System (CMAS) notification.

[0163] In some examples, determining to monitor signaling associated with updated or changed multicast broadcast service (MBS)-related parameters may be further based on the user equipment (UE) being an MBS UE.

[0164] In some examples, the multicast broadcast service (MBS) related parameters may include semi-persistent scheduling (SPS) configuration parameters for receiving MBS data.

[0165] In some examples, a Multicast Broadcast Service (MBS) notification received based on the Downlink Control Information (DCI) may indicate one or more of the following: a notification type, a target MBS service type, a target MBS service or group identifier (ID), and an uplink feedback or response. In some examples, the notification type includes at least one of a Multicast Broadcast Service (MBS) system information update, an MBS session start / activation or an MBS session stop / deactivation, an MBS configuration change before or during an active session, and an MBS count order for soliciting interest indications. In some examples, the Multicast Broadcast Service (MBS) service type is one of a plurality of MBS service types including a multicast service type and a broadcast service type. In some examples, the target Multicast Broadcast Service (MBS) service or group identifier (ID) may be from a plurality of target MBS service or group IDs including an MBS paging ID and a temporary mobile group identity (TMGI). In some examples, the uplink feedback or response may include a trigger to use and a resource need.

[0166] In some examples, the plurality of bits may comprise a flag indicating the presence of a multicast broadcast service (MBS) notification. In some examples, the flag may include a bit. A first value of the bit may indicate the presence of a multicast broadcast service (MBS) notification. A second value of the bit may indicate the absence of an MBS notification. In some examples, the first value may be 1. The second value may be 0. In some examples, the flag may be ignored by non-multicast broadcast service (MBS) user equipment (UE).

[0167] In some examples, the plurality of bits may include one or more fourth bits indicating a change in a multicast broadcast service (MBS) system information block (SIB). In some examples, the multicast broadcast service (MBS) system information block (SIB) may indicate random access resources. In some examples, the random access resources may be used by a user equipment (UE) for multicast broadcast service (MBS) interest indication signaling. In some examples, a multicast broadcast service (MBS) notification may comprise an information element indicating a request for an MBS interest indication. Receipt of the MBS notification may trigger MBS interest indication signaling by the UE. In some examples, transmission of the interest indication signaling may be based on a randomization seed or according to a probability. In some examples, the UE may receive a configuration parameter indicating the randomization seed or the probability. In some examples, the random access resources may include a first random access resource associated with a first beam. In some examples, the random access resources may be divided into multiple random access resource sets. Each random access resource set in the plurality of random access resource sets may be associated with a corresponding beam or distribution unit (DU).

[0168] In some examples, one or more bits may have one of multiple values. Each value of the multiple values ​​may be mapped to a combination of modifications or changes. In some examples, the combination of modifications or changes may be preconfigured. In some examples, the combination of modifications or changes may be configurable. In some examples, the UE may receive system information indicating the combination of modifications or changes. In some examples, the UE may receive one or more radio resource control (RRC) configuration parameters indicating the combination of modifications or changes. In some examples, one or more bits may be ignored by non-MBS UEs.

[0169] The example blocks and modules described in this disclosure with respect to various example embodiments may be implemented or performed using a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. Examples of general-purpose processors include, but are not limited to, a microprocessor, any conventional processor, controller, microcontroller, or state machine. In some examples, a processor may be implemented using a combination of devices (e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in combination with a DSP core, or any other such configuration).

[0170] The functions described in this disclosure may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. Instructions or code may be stored on or transmitted to a computer-readable medium to implement the functions. Other examples for implementing the functions disclosed herein are also within the scope of this disclosure. Implementation of the functions may be via physically co-located or distributed elements (e.g., in various locations), including being distributed such that some of the functions are implemented in different physical locations.

[0171] Computer-readable media include, but are not limited to, non-transitory computer storage media. Non-transitory storage media may be accessed by a general-purpose or special-purpose computer. Examples of non-transitory storage media include, but are not limited to, random access memory (RAM), read-only memory (ROM), electrically erasable programmable ROM (EEPROM), flash memory, compact disc (CD) ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, etc. Non-transitory media may be used to carry or store desired program code means (e.g., instructions and / or data structures) and may be accessed by a general-purpose or special-purpose computer or a general-purpose or special-purpose processor. In some examples, software / program code may be transmitted from a remote source (e.g., a website, a server, etc.) using coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, microwave, etc. 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 medium. Combinations of the above examples are also included within the scope of computer-readable media.

[0172] As used in this disclosure, the use of the term "or" in a list of items indicates an inclusive list. A list of items may be preceded by a phrase such as "at least one" or "one or more." For example, a list of at least one of A, B, or C includes A or B or C or AB (i.e., A and B) or AC or BC or ABC (i.e., A and B and C). Also, as used in this disclosure, the phrase "based on" preceding a list of conditions should not be interpreted as "based only on" the set of conditions, but rather as "based at least in part on" the set of conditions. For example, a result described as "based on condition A" may be based on both condition A and condition B without departing from the scope of this disclosure.

[0173] As used herein, the terms "comprise," "include," or "contain" may be used interchangeably, have the same meaning, and should be construed as inclusive and open-ended. The terms "comprise," "include," or "contain" may be used before a list of elements to indicate that at least all of the listed elements in the list are present, but that other elements not in the list may also be present. For example, if A comprises B and C, then both {B,C} and {B,C,D} are within the scope of A.

[0174] The present disclosure, in connection with the accompanying drawings, describes exemplary configurations that do not represent all examples that may be implemented or all configurations within the scope of the present disclosure. The term "exemplary" should not be interpreted as "preferred" or "advantageous compared to other examples," but rather as "an example, instance, or example." By reading this disclosure, including the description of the embodiments and drawings, those skilled in the art will understand that the technology disclosed herein may be implemented using alternative embodiments. Those skilled in the art will understand that embodiments, or specific features of the embodiments described herein, may be combined to arrive at yet other embodiments for implementing the technology described in this disclosure. Thus, the present disclosure is not limited to the examples and designs described herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for multicast broadcast service (MBS) notification signaling, comprising: receiving, by a user equipment (UE), downlink control information (DCI), wherein the DCI is associated with a first radio network temporary identifier (RNTI) corresponding to at least an MBS-related notification, wherein the DCI includes a field including a plurality of bits, receiving, by the UE, one or more bits of the plurality of bits of the field indicating an update or change to one or more MBS-related parameters; determining to monitor signaling indicating updated or changed MBS-related parameters based on an indication by the one or more bits; receiving MBS data based on the updated or changed MBS-related parameters; and a method comprising the steps of:

2. The method according to claim 1, wherein receiving the downlink control information (DCI) is based on a physical downlink control channel (PDCCH).

3. The method according to claim 1, wherein receiving the downlink control information (DCI) is performed while the user equipment (UE) is in a radio resource control (RRC) connected state.

4. The method according to claim 1, wherein receiving the downlink control information (DCI) is performed while the user equipment (UE) is in a radio resource control (RRC) idle state or an RRC inactive state.

5. The method according to claim 4, wherein receiving the downlink control information (DCI) is performed based on monitoring a downlink control channel at a monitoring opportunity determined based on a discontinuous reception (DRX) procedure in the radio resource control (RRC) idle state or the RRC inactive state.

6. The first radio network temporary identifier (RNTI) is a paging RNTI, The downlink control information (DCI) is associated with the transmission of paging information, The method according to claim 1.

7. The method according to claim 1, wherein the first radio network temporary identifier (RNTI) is a multicast broadcast service (MBS)-RNTI.

8. The method according to claim 1, wherein one or more bits of the plurality of bits of the field indicate a broadcast control channel (BCCH) change.

9. Determining to monitor signaling associated with the updated or changed MBS-related parameter is further based on the user equipment (UE) being an MBS UE, the method according to claim 1.

10. The method according to claim 1, wherein the MBS-related parameter includes semi-persistent scheduling (SPS) configuration parameters for receiving MBS data.

11. The multicast broadcast service (MBS) notification received based on the downlink control information (DCI) is Notification type, Target MBS service type, Target MBS service or group identifier (ID), and Uplink feedback or response, The method according to claim 1, indicating one or more of.

12. The notification type is Multicast broadcast service (MBS) system information update, MBS session start / activation or MBS session stop / deactivation, MBS configuration change before or during an active session, and The count order of the MBS for requesting an interest indication The method according to claim 11, comprising at least one of **Claim 13** The method according to claim 11, wherein the target MBS service type is one of a plurality of MBS service types including a multicast service type and a broadcast service type. **Claim 14** The method according to claim 11, wherein the target MBS service or group identifier (ID) is from a plurality of target MBS services or group IDs including an MBS paging ID and a provisional mobile group identity (TMGI). **Claim 15** The method according to claim 11, wherein the uplink feedback or response includes the triggers used and the need for resources. **Claim 16** The method according to claim 1, wherein the plurality of bits comprises a flag indicating the presence of a multicast broadcast service (MBS) notification. **Claim 17** The flag includes bits A first value of the bit indicates the presence of the MBS notification A second value of the bit indicates the absence of the MBS notification The method according to claim 16. **Claim 18** The first value is 1 The second value is 0 The method according to claim 17. **Claim 19** The method according to claim 16, wherein the flag is ignored by a non-multicast broadcast service (MBS) user equipment (UE). **Claim 20** The method according to claim 1, wherein the plurality of bits of the field includes one or more first bits indicating a change in a Multicast Broadcast Service (MBS) System Information Block (SIB).

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