System and method for maintaining multicast broadcast service continuity in idle and inactive states

Abstract

To maintain MBS service continuity in idle and inactive states.SOLUTION: A method includes steps of: receiving system information including first information used for measuring neighboring cells in an RRC inactive state or an RRC idle state; performing measurements of the neighboring cells based on the first information and performing cell reselection; receiving second information indicating whether an MBS service is provided in the neighboring cells; acquiring third information that is information indicating a frequency at which the MBS service is provided in the neighboring cells and that is different from the second information; and receiving data associated with the MBS service via a cell-reselected target cell while remaining in the RRC inactive state or the RRC idle state based on the third information.SELECTED DRAWING: Figure 18

Description

[Technical Field]

[0001] The present disclosure relates to a method for maintaining service continuity. [Background technology]

[0002] Generally, computing devices and communication networks can be used to exchange information. In typical applications, computing devices can request / send data to other computing devices via a communication network. More specifically, computing devices can use wireless communication networks to exchange information or establish communication channels.

[0003] A wireless communication network may include various types of devices that include components for accessing the wireless communication network or that access the wireless communication network, and such devices may utilize the wireless communication network to facilitate interaction with other devices that have access to the wireless communication network or to facilitate interaction through the wireless communication network with devices that utilize other communication networks. Summary of the Invention [Means for solving the problem]

[0004] One embodiment of the present invention is a method for maintaining service continuity. The method is a processing method for a user equipment (UE) receiving one or more multicast / broadcast services (MBS) during cell reselection, the UE being in at least one of a radio resource control (RRC) inactive state and an RRC idle state, for maintaining the continuity of the MBS services during cell reselection. The method includes the steps of receiving system information including first information used for measuring neighboring cells in the RRC inactive state or the RRC idle state, performing measurements on the neighboring cells based on the first information and performing cell reselection, receiving second information indicating whether the MBS services are provided in the neighboring cells, acquiring third information indicating a frequency on which the MBS services are provided in the neighboring cells and different from the second information, and receiving data associated with the MBS services via the target cell for cell reselection based on the third information while remaining in the RRC inactive state or the RRC idle state. [Brief explanation of the drawings]

[0005] [Figure 1] 1 illustrates an example of a mobile communication system in accordance with some aspects of one or more exemplary embodiments of the present disclosure. [Figure 2] 2A-2B illustrate example radio protocol stacks for the user plane and control plane, respectively, in accordance with some aspects of one or more exemplary embodiments of the present disclosure. [Figure 3] 3A-3C illustrate example mappings between logical channels and transport channels for the downlink, uplink, and sidelink, respectively, in accordance with some aspects of one or more exemplary embodiments of the present disclosure. [Figure 4] 4A-4C illustrate example mappings between transport channels and physical channels for the downlink, uplink, and sidelink, respectively, in accordance with some aspects of one or more exemplary embodiments of the present disclosure. [Figure 5] 5A-5D illustrate example radio protocol stacks for NR sidelink communications in accordance with some aspects of one or more exemplary embodiments of the present disclosure. [Figure 6] 1 illustrates exemplary physical signals for downlink, uplink, and sidelink in accordance with some aspects of one or more exemplary embodiments of the present disclosure. [Figure 7] 1 illustrates examples of Radio Resource Control (RRC) states and transitions between different RRC states in accordance with some aspects of one or more exemplary embodiments of the present disclosure. [Figure 8] 1 illustrates an example frame structure and physical resources in accordance with some aspects of one or more example embodiments of the present disclosure. [Figure 9] 1 illustrates exemplary component carrier configurations for different carrier aggregation scenarios in accordance with some aspects of one or more exemplary embodiments of the present disclosure. [Figure 10] 1 illustrates exemplary bandwidth portion configurations and switching in accordance with some aspects of one or more exemplary embodiments of the present disclosure. [Figure 11] 1 illustrates an exemplary four-stage collision-based and non-collision-based random access process in accordance with some aspects of one or more exemplary embodiments of the present disclosure. [Figure 12] 1 illustrates an exemplary two-stage collision-based and non-collision-based random access process in accordance with some aspects of one or more exemplary embodiments of the present disclosure. [Figure 13] 1 illustrates an example time-frequency structure of a synchronization signal / physical broadcast channel (PBCH) block (SSB) in accordance with some aspects of one or more example embodiments of the present disclosure. [Figure 14] 1 illustrates an exemplary SSB burst transmission in accordance with some aspects of one or more exemplary embodiments of the present disclosure. [Figure 15] 1 illustrates exemplary components of a user terminal and a base station for transmission and / or reception in accordance with some aspects of one or more exemplary embodiments of the present disclosure. [Figure 16A]1 illustrates an example RRC restart procedure in accordance with some aspects of one or more example embodiments of the present disclosure. [Figure 16B] 1 illustrates an example RRC restart procedure in accordance with some aspects of one or more example embodiments of the present disclosure. [Figure 16C] 1 illustrates an example RRC restart procedure in accordance with some aspects of one or more example embodiments of the present disclosure. [Figure 16D] 1 illustrates an example RRC restart procedure in accordance with some aspects of one or more example embodiments of the present disclosure. [Figure 16E] 1 illustrates an example RRC restart procedure in accordance with some aspects of one or more example embodiments of the present disclosure. [Figure 17] 1 illustrates an example process for service continuity in RRC inactive and / or RRC idle states. [Figure 18] 1 illustrates an example process for service continuity in RRC inactive and / or RRC idle states. [Figure 19] 1 illustrates an example process for service continuity in RRC inactive and / or RRC idle states. DETAILED DESCRIPTION OF THE INVENTION

[0006] 1 illustrates an example of a mobile communication system 100 according to some aspects of one or more exemplary embodiments of the present disclosure. The mobile communication system 100 may be operated by a wireless communication system operator, such as a Mobile Network Operator (MNO), a private network operator, a Multiple System Operator (MSO), an Internet of Things (IoT) network operator, etc., and may provide services such as voice, data (e.g., wireless Internet access), messaging, automotive communication services such as vehicle-to-vehicle / vehicle-to-everything (V2X) communication services, safety services, mission-critical services, IoT, industrial IoT (IIOT), and other services in residential, commercial, or industrial environments.

[0007] The mobile communication system 100 may support a variety of applications with different requirements in terms of latency, reliability, throughput, etc. Examples of supported applications include enhanced Mobile Broadband (eMBB), Ultra-Reliable Low-Latency Communications (URLLC), and massive Machine Type Communication (mMTC). eMBB can support high peak data rates and stable connections at reasonable rates for cell edge users. URLLC has stringent requirements for latency and reliability, but can support applications with moderate data rate requirements. An exemplary mMTC application includes a network of numerous IoT devices that are only sporadically active and transmit only small data payloads.

[0008] 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 (5g-CN) 110 as examples of the RAN and core network, respectively. Other examples of the RAN and core network may also be implemented without departing from the scope of this disclosure. Other examples of the RAN include the Evolved Universal Terrestrial Radio Access Network (EUTRAN), Universal Terrestrial Radio Access Network (UTRAN), and the Universal Terrestrial Radio Access Network (UTRAN). Examples of core networks include Universal Terrestrial Radio Access Network (UTRAN), etc. Other examples of core networks include Evolved Packet Core (EPC), UMTS Core Network (UCN), etc. The RAN implements a Radio Access Technology (RAT) and is located between user equipments (UEs) 125 and the core network. Such RATs include New Radio (NR), Long Term Evolution (LTE), also known as Evolved Universal Terrestrial Radio Access (EUTRA), Universal Mobile Telecommunication System (UMTS), etc. The RAT in the exemplary mobile communication system 100 may be NR. The core network is located 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 the application of different Quality of Services (QoS). The functional layer between the UE 125 and the RAN (e.g., the NG-RAN 105) may be referred to as the Access Stratum (AS), and the functional layer between the UE 125 and the core network (e.g., the 5G-CN 110) may be referred to as the Non-access Stratum (NAS).

[0009] The UEs 125 may include wireless transmission and reception means for communicating with one or more nodes in the RAN, one or more relay nodes, or one or more other UEs. Examples of UEs include, but are not limited to, smartphones, tablets, laptops, computers, in-vehicle wireless transmit and / or receive units, V2X or vehicle-to-vehicle (V2V) devices, wireless sensors, IoT devices, IIOT devices, etc. Other names for UEs may be used, such as mobile stations (MS), terminal equipment, terminal nodes, client devices, mobile devices, etc. Furthermore, the UEs 125 may also include components or subcomponents embedded in other devices, such as automobiles, that provide wireless communication capabilities with nodes in the RAN as described herein. Such other devices may have other functionality or multiple functionalities in addition to wireless communication.

[0010] 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 (e.g., base stations) for communicating with UEs 125. The RAN nodes may include a base station (RAN node). Various names may be used for the RAN, depending, for example, on the RAT used for the RAN. A RAN node may be called a Node-B (NB) in a RAN using the UMTS RAT. A RAN node may be called an evolved Node B in a RAN using the LTE / EUTRA RAT. In the example mobile communication system 100 of FIG. 1, the NG-RAN 105 node may be either a Next Generation Node B (gNB) 115 or a Next Generation Evolved Node B (ng-eNB) 120. The terms base station, RAN node, gNB, and ng-eNB may be used interchangeably herein. Illustratively, a communication network may be characterized as a collection of geographic areas, referred to as cells, logically organized contiguously. The cells are organized in such a way that each cell may be associated with one or more base stations that establish wireless communication with multiple UEs. A base station is physically located within each cell, and wireless radio signals transmitted from that cell may be received by UEs also physically located within that cell. In other embodiments, a base station may be located outside a physical cell and configured to transmit wireless signals to UEs within that cell. In some embodiments, individual UEs may be able to receive signals transmitted between adjacent cells due to overlapping signaling coverage. Thus, references to communications from a target cell or an existing cell may refer to a connection between UE 125 and one or more base stations belonging to that cell.

[0011] The gNB 115 may provide NR user plane and control plane protocol termination toward the UE 125. The ng-eNB 120 may provide E-UTRA user plane and control plane protocol termination toward the UE 125. The interface between the gNB 115 and the UE 125 or between the ng-eNB 120 and the UE 125 may be referred to as a Uu interface. The Uu interface may be established with a user plane protocol stack and a control plane protocol stack. For the Uu interface, the direction from the base station (e.g., 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.

[0012] The gNBs 115 and the ng-eNBs 120 may be interconnected via 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 based on Internet Protocol (IP) transport, and the GPRS Tunneling Protocol (GTP) may be used over User Datagram Protocol (UDP) / IP to carry user plane protocol data units (PDUs). The Xn-U may provide unguaranteed delivery of user plane PDUs and may support data forwarding and flow control. The transport network layer of the Xn-C interface may be based on the Stream Control Transport Protocol (SCTP) over IP. The application layer signaling protocol may be called the Xn Application Protocol (XnAP). The SCTP layer may provide guaranteed delivery of application layer messages. At the transport IP layer, point-to-point transport may be used to transport signaling PDUs. The Xn-C interface may support Xn interface management, UE mobility management including context transfer and RAN paging, and dual connectivity.

[0013] The gNBs 115 and ng-eNBs 120 may also be connected to the 5GC 110 by an NG interface, more specifically to the Access and Mobility Management Function (AMF) 130 of the 5GC 110 by an NG-C interface, and to the User Plane Function (UPF) 135 of the 5GC 110 by an NG-U interface. The transport network layer of the NG-C interface may be built based on IP transport, and the GTP protocol may be used on top of UDP / IP to carry user plane PDUs between the NG-RAN node (e.g., gNB 115 or ng-eNB 120) and the UPF 135. The NG-U may provide unguaranteed delivery of user plane PDUs between the NG-RAN node and the UPF. The transport network layer of the NG-C interface may be built based on IP transport. For reliable transfer of signaling messages, SCTP may be added on top of IP. The application layer signaling protocol may be called 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 transfer 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.

[0014] gNB 115 or ng-eNB 120 may host one or more of the following functions: radio bearer control, radio admission control, connection mobility control, dynamic allocation of resources to UEs in both uplink and downlink (e.g., scheduling), IP and Ethernet header compression, ciphering, and data integrity protection, selection of an AMF at UE attachment if routing to the AMF cannot be determined from information provided by the UE, routing of user plane data towards the UPF, routing of control plane information towards the AMF, connection setup and release, scheduling and transmission of paging messages, scheduling and transmission of system broadcast information (e.g., originating from the AMF), measurement and measurement report 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, distribution functions for NAS messages, radio access network sharing, dual connectivity, close interworking between NR and E-UTRA, security and radio configuration for user plane 5G system (5GS) Cellular IoT (CIoT) optimization.

[0015] The AMF 130 may host one or more of the following functions: NAS signal termination, NAS signaling security, AS security control, CN inter-node signaling for mobility between 3GPP access networks, idle mode UE reachability (including control and execution of paging retransmissions), registration area management, support for intra-system and inter-system mobility, access authentication, access authorization including checking roaming rights, mobility management control (subscriptions and policies), support for network slicing, selection of Session Management Function (SMF), selection of 5GS CIoT optimization.

[0016] The UPF 135 may host one or more of the following functions: anchor points for Intra- / Inter-RAT mobility (if applicable), external PDU session points for interconnection with data networks, packet routing and forwarding, packet inspection and policy rule enforcement for the user plane part, traffic utilization reporting, uplink classifier to support routing of traffic flows to the data network, branching points to support multi-homed PDU sessions, QoS handling for the user plane, e.g., packet filtering, gating, UL / DL rate enforcement, uplink traffic validation (mapping of Service Data Flows (SDF) to QoS flows), downlink packet buffering and downlink data notification triggering.

[0017] As shown in FIG. 1, the NG-RAN 105 includes two UEs 125 (e.g., UE The NG-RAN 105 may support a PC5 interface between two UEs (UE 125A and UE 125B). In the PC5 interface, the communication direction between 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, regardless of the RRC state the UE is in, and when the UE 125 is outside NG-RAN 105 coverage. Support for V2X services over the PC5 interface may be provided by NR sidelink communication and / or V2X sidelink communication.

[0018] PC5-S signaling can be used to establish a unicast link via a direct communication request / accept message. A UE can self-generate its source Layer-2 ID for a PC5 unicast link, for example, based on the V2X service type. During the unicast link establishment procedure, a UE can transmit its egress Layer-2 ID for the PC5 unicast link to a peer UE, for example, a UE for which a destination ID has been received from a higher layer. The pair of source Layer-2 ID and destination Layer-2 ID can uniquely identify a unicast link. The receiving UE can verify that the destination ID belongs to it and accept the unicast link establishment request from the egress UE. During the PC5 unicast link establishment procedure, a PC5-RRC procedure at the access stratum can be performed for the purpose of establishing a UE sidelink context, as well as for AS layer configuration, capability exchange, etc. PC5-RRC signaling can enable UE capability exchange and AS layer configuration, such as sidelink radio bearer configuration, between a pair of UEs with established PC5 unicast links.

[0019] NR sidelink communication may support one of three transmission modes (e.g., unicast transmission, groupcast transmission, and broadcast transmission) for a pair of source and destination Layer-2 IDs within an AS. The unicast transmission mode may be characterized by supporting one PC5-RRC connection between peer UEs for the pair, transmitting and receiving control information and user traffic between peer UEs in the sidelink, supporting sidelink HARQ feedback, supporting sidelink transmit power control, supporting RLC Acknowledged Mode (AM), and detecting radio link failures for the PC5-RRC connection. The groupcast transmission is characterized by transmitting and receiving user traffic between UEs belonging to the group in the sidelink, and supporting sidelink HARQ feedback. The broadcast transmission may be characterized by transmitting and receiving user traffic between UEs in the sidelink.

[0020] The source Layer-2 ID, destination Layer-2 ID, and PC5 link identifier may be used for NR sidelink communications. The source Layer-2 ID may identify the sender 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, where one bit string is the least significant bit (8 bits) of the source Layer-2 ID and is transmitted to the sender's physical layer. This may identify the intended data source in the sidelink control information and may be used for packet filtering at the receiver's physical layer. In this case, the second bit string may be the most significant bit (16 bits) of the source Layer-2 ID and is carried in the media 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 communications. For NR sidelink communications, the destination Layer-2 ID may be 24 bits long and may be split into two bit strings at the MAC layer, where one bit string is the least significant bit (16 bits) of the destination Layer-2 ID and is sent 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, where the second bit string is the most significant bit (8 bits) of the destination Layer-2 ID. ) and may be carried in the MAC header. This may be used for packet filtering at the receiver's MAC layer. The PC5 link identifier may uniquely identify a PC5 unicast link in a UE for the lifetime of the PC5 unicast link. The PC5 link identifier may be used to identify the PC5 unicast link for which a sidelink Radio Link Failure (RLF) has been declared and the PC5-RRC connection has been released.

[0021] 2A and 2B illustrate example radio protocol stacks for the user plane and control plane, respectively, in accordance with some aspects of one or more exemplary embodiments of the present disclosure. As shown in FIG. 2A, the user plane protocol stack for 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, Layer 2 MAC 204 and MAC 214, and Physical Layer (PHY) 205 and PHY 215 layers (Layer 1 also referred to as L1).

[0022] The PHY 205 and PHY 215 provide transport channels 244 to the MAC 204 and MAC 214 sublayers. The MAC 204 and MAC 214 sublayers provide logical channels 243 to the RLC 203 and RLC 213 sublayers. The RLC 203 and RLC 213 sublayers provide RLC channels 242 to the PDCP 202 and PCP 212 sublayers. The PDCP 202 and PDCP 212 sublayers provide radio bearers 241 to the SDAP 201 and SDAP 211 sublayers. 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.

[0023] The main services and functions of the MAC 204 or MAC 214 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 (TB) conveyed on transport channels to / from the physical layer, scheduling of information reports, error correction through Hybrid Automatic Repeat Request (HARQ) (one HARQ entity per cell in case of Carrier Aggregation (CA)), priority handling between UEs by dynamic scheduling, priority handling between logical channels of one UE by Logical Channel Prioritization (LCP), priority handling between overlapping resources of one UE, and padding. One MAC entity may support multiple numerologies, transmission timings, and cells. The mapping of priority decisions within a logical channel controls which numerology, cell, and transmission timing a logical channel may use.

[0024] The HARQ function may ensure communication between peer entities at Layer 1. One HARQ process may support one TB if the physical layer is not configured for downlink / uplink spatial multiplexing, and one or more TBs if the physical layer is configured for downlink / uplink spatial multiplexing.

[0025] The RLC 203 or RLC 213 sublayer may support three transmission modes: Transparent Mode (TM), Unacknowledged Mode (UM), and Acknowledged Mode (AM). The RLC configuration may be according to the logical channel, independent of the numerology and / or transmission time, and Automatic Repeat Request (ARQ) may operate with either the numerology and / or transmission time for which the logical channel is configured.

[0026] The main services and functions of the RLC 203 or RLC 213 sublayer depend on the transmission mode (e.g., TM, UM, or AM) and may include: transmission of higher layer PDUs, independent sequence numbering within PDCP (UM and AM), error correction through ARQ (AM only), segmentation (AM and UM) and re-segmentation (AM only) of RLC SDUs, reassembly of SDUs (AM and UM), duplicate detection (AM only), RLC SDU discard (AM and UM), RLC re-establishment, and protocol error detection (AM only).

[0027] An automatic repeat request in the RLC 203 or RLC 213 sublayer may have the following properties: ARQ retransmits RLC SDUs or RLC SDU segments based on an RLC status report; polling of RLC status reports may be used by the RLC as needed; the RLC receiver may also trigger an RLC status report after detecting a missed RLC SDU or RLC SDU segment.

[0028] The main services and functions of the PDCP 202 or PDCP 212 sublayer include: transmission of data (user plane or control plane), preservation of PDCP sequence numbers (SNs), header compression and decompression using the Robust Header Compression (ROHC) protocol, encryption and decryption, integrity protection and integrity verification, timer-based SDU discard, routing for split bearers, duplication, reordering and in-order delivery, out-of-order delivery, and duplicate discard.

[0029] The main services and functions of the SDAP 201 or SDAP 211 include: mapping between QoS flows and data radio bearers, marking of QoS Flow ID (QFI) in both downlink and uplink. One protocol entity of the SDAP can be configured for each individual PDU session.

[0030] As shown in FIG. 2B, the control plane protocol stack of the Uu interface (between the UE 125 and the gNB 115) includes the PHY layer (Layer 1) as described above, and the MAC, RLC, and PDCP sublayers of Layer 2, as well as the RRC 206 and RRC 216 sublayers. The main services and functions of the RRC 206 and RRC 216 sublayers on the Uu interface include: broadcasting system information about the AS and NAS; paging initiated by 5GC or NG-RAN; establishment, maintenance, and release of the RRC connection between the UE and NG-RAN (including adding, modifying, and releasing carrier aggregation and adding, modifying, and releasing dual connectivity within the NR or between 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 cell selection and reselection control, and inter-RAT mobility); QoS management functions; UE measurement result reporting and reporting control; detection and recovery from radio link failure; and transmission of NAS messages from the NAS to the UE and from the UE to the NAS. The NAS 207 and NAS 227 layers are control protocols (terminated in the AMF on the network side) that perform functions such as authentication, mobility management, and security control.

[0031] Sidelink specific services and functions of the RRC sublayer on the Uu interface include: configuration of sidelink resource allocation via system information or dedicated signaling, reporting of UE sidelink information, configuration and reporting of sidelink related measurements, reporting of UE assistance information for SL traffic patterns.

[0032] 3A, 3B, and 3C illustrate example mappings between logical channels and transport channels in the downlink, uplink, and sidelink, respectively, according to some aspects of one or more example embodiments of the present disclosure. Different types of data transmission services may be provided by the MAC. Each logical channel type may be defined by the type of information transmitted. Each logical channel may be classified into two groups: control channels and traffic channels. The control channels may be used for transmitting control plane information only. The Broadcast Control Channel (BCCH) is a downlink channel for broadcasting system control information. The Paging Control Channel (PCCH) is a downlink channel for carrying paging messages. The Common Control Channel (CCCH) is a channel for transmitting control information between UEs and the network. This channel may be used for UEs that do not have an RRC connection with the network. The Dedicated Control Channel (DCCH) is a point-to-point bidirectional channel for transmitting dedicated control information between a UE and the network and may be used by UEs that have an RRC connection. A traffic channel can be used to transmit user plane information only. A dedicated traffic channel (DTCH) is a point-to-point channel dedicated to one UE for the transmission of user information. A DTCH can exist in both the uplink and downlink. A sidelink control channel (SCCH) is a A Sidelink Traffic Channel (STCH) is a sidelink channel for transmitting control information (e.g., PC5-RRC and PC5-S messages) from one UE to another. The Sidelink Broadcast Control Channel (SBCCH) is a sidelink channel for transmitting user information from one UE to other UEs. The Sidelink Broadcast Control Channel (SBCCH) is a sidelink channel for broadcasting sidelink system information from one UE to other UEs.

[0033] Types of downlink transport channels include the Broadcast Channel (BCH), the Downlink Shared Channel (DL-SCH), and the Paging Channel (PCH). The BCH may be characterized by a fixed, predefined transport format and a requirement to be broadcast throughout the coverage area of ​​a cell, either as a standalone message or by beamforming different BCH instances. The DL-SCH may be characterized by support for HARQ, support for dynamic link modulation adaptation by varying modulation, coding, and transmit power, the possibility of cell-wide broadcast, the possibility of beamforming, support for both dynamic and semi-static resource allocation, and support for UE discontinuous reception (DRX) for UE power consumption savings. The DL-SCH may be characterized by support for HARQ, support for dynamic link modulation adaptation by varying modulation, coding, and transmit power, the possibility of cell-wide broadcast, the possibility of beamforming, support for both dynamic and semi-static resource allocation, and support for UE discontinuous reception (DRX) for UE power consumption savings. The PCH may be characterized by support for UE discontinuous reception (DRX) to allow UE power consumption savings (DRX cycles are indicated to the UE by the network), requirements broadcast throughout the coverage area of ​​the cell either as a standalone message or by beamforming different BCH instances, and dynamic mapping to physical resources that can also be used for traffic / other control channels.

[0034] In the downlink, the following connections between logical channels and transport channels may exist: 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.

[0035] Types of uplink transport channels include the Uplink Shared Channel (UL-SCH) and the Random Access Channel (RACH). The UL-SCH may be characterized by the availability of beamforming, support for dynamic link modulation adaptation by varying transmit power and possibly modulation and coding, support for HARQ, and support for both dynamic and semi-static resource allocation. The RACH may be characterized by limited control information and collision risk.

[0036] 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.

[0037] Types of sidelink transport channels include: Sidelink Broadcast Channel (SL-BCH) and Sidelink Shared Channel (SL-SCH). The SL-BCH may be characterized by a predefined transport format. The SL-SCH may be characterized by supporting unicast, groupcast, and broadcast transmissions, supporting both UE automatic resource selection and scheduled resource allocation by the NG-RAN, supporting both dynamic and semi-static resource allocation when the UE is assigned resources by the NG-RAN, supporting HARQ, and supporting dynamic link modulation adaptation by varying transmit power, modulation, and coding.

[0038] 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.

[0039] 4A, 4B, and 4C illustrate example mappings between transport channels and physical channels in the downlink, uplink, and sidelink, respectively, in accordance with some aspects of one or more exemplary embodiments of the present disclosure. The downlink physical channels 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. Although no transport channels are mapped to the PDCCH, downlink control information (DCI) is transmitted via the PDCCH.

[0040] Uplink physical channels include the Physical Uplink Shared Channel (Physical Uplink Control Channel), the Physical Uplink Control Channel (PUCCH), and the Physical Random Access Channel (Physical Random Access Channel). The UL-SCH transport channel can be mapped to the PUSCH, and the RACH transport channel can be mapped to the PRACH. The transport channels are not mapped to the PUCCH, but uplink control information (UCI) is transmitted via the PUCCH.

[0041] 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 that a UE uses for the PSSCH. The Physical Sidelink Shared Channel (PSSCH) may transmit TBs of data itself, control information for the HARQ procedure, and CSI feedback triggers. At least six OFDM symbols within a slot may be used for PSSCH transmission. The Physical Sidelink Feedback Channel (PSFCH) may carry HARQ feedback on the sidelink from the UE that is the intended recipient of a PSSCH transmission to the UE that transmitted it. The PSFCH sequence may be transmitted in one PRB repeated in two OFDM symbols near the end of the sidelink resources within a slot. The SL-SCH transport channel may be mapped to the PSSCH. The SL-BCH may be mapped to the PSBCH. None of the transport channels may be mapped to the PSFCH, but Sidelink Feedback Control Information (SFCI) may be mapped to the PSFCH. None of the transport channels may be mapped to the PSCCH, but Sidelink Control Information (SCI) may be mapped to the PSCCH.

[0042] 5A, 5B, 5C, and 5D illustrate example radio protocol stacks for NR sidelink communications in accordance with some aspects of one or more exemplary embodiments of the present disclosure. The AS protocol stack for the user plane (i.e., for the STCH) in the PC5 interface may consist of the SDAP, PDCP, RLC, and MAC sublayers and a physical layer. The user plane protocol stack is shown in FIG. 5A. The AS protocol stack for the SBCCH in the PC5 interface may consist of the RRC, RLC, and MAC sublayers and a physical layer shown below in FIG. 5B. To support the PC5-S protocol, PC5-S resides 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 FIG. 5C. The AS protocol stack for the control plane of the SCCH for RRC in 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 FIG. 5D.

[0043] Sidelink Radio Bearers (SLRBs) are divided into two groups: Sidelink Data Radio Bearers for user plane data and Sidelink Data Radio Bearers for user plane data. The sidelink signaling radio bearers (SL DRBs) for control plane data and sidelink signaling radio bearers (SL SRBs) for control plane data can be configured for PC5-RRC and PC5-S signaling, respectively. Separate SLSRBs using different SCCHs can be configured for PC5-RRC and PC5-S signaling, respectively.

[0044] 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 UE, and sidelink CSI reporting. Due to the constraints of logical channel prioritization within 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 that destination. For packet filtering, an SL-SCH MAC header containing both the source and destination Layer-2 ID portions 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 and destination Layer-2 IDs.

[0045] 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, but 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.

[0046] The services and functions of the PDCP sublayer of the Uu interface can be supported for the sidelink with some restrictions: out-of-order delivery can only be supported for unicast transmission, and duplexing is not supported on the PC5 interface.

[0047] The SDAP sublayer may provide the following services and functions over the PC5 interface: mapping between QoS flows and sidelink data radio bearers. For one destination, there may be one SDAP entity for one of unicast, groupcast, and broadcast associated with that destination.

[0048] The RRC sublayer may provide the following services and functions over the PC5 interface: transmission of PC5-RRC messages between peer UEs, maintenance and release of a PC5-RRC connection between two UEs, and detection of sidelink radio link failure for a PC5-RRC connection based on indications from MAC or RLC. A PC5-RRC connection may be a logical connection between two UEs for a pair of source and destination Layer-2 IDs that can be considered established after the 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 and destination Layer-2 IDs. Separate PC5-RRC procedures and messages may be used for a given UE to transmit UE capabilities and sidelink configurations, including SL-DRB configurations, to a peer UE. Both peer UEs may exchange their respective UE capabilities and sidelink configurations using separate bidirectional procedures for both sidelink directions.

[0049] 6 illustrates exemplary physical signals for the downlink, uplink, and sidelink in accordance with some aspects of one or more exemplary embodiments of the present disclosure. Demodulation Reference Signals (DM-RS) may be used in the downlink, uplink, and sidelink and may be used for channel estimation. DM-RS is a UE-specific reference signal and may be used to estimate the downlink, uplink, and sidelink along with the physical channel. The PT-RS may be transmitted in the downlink, uplink, or sidelink and may be used for channel estimation and coherent detection of the physical channel. The Phase Tracking Reference Signal (PT-RS) may be used in the downlink, uplink, and sidelink and may be used for phase tracking and mitigating performance loss due to phase noise. The PT-RS may be primarily used to estimate and minimize the impact of Common Phase Error (CPE) on system performance. Due to phase noise characteristics, the PT-RS signal may be sparse in the frequency domain and dense in the time domain. The PT-RS may occur in combination with DM-RS or when the network is configured to have PT-RS present. The Positioning Reference Signal (PRS) may be used in the downlink for positioning using different positioning technologies. The PRS may be used to measure the delay of downlink transmission by correlating the received signal from the base station with a local replica in the receiver. The Channel State Information Reference Signal (CSI-RS) may be used to measure the delay of downlink transmission by correlating the received signal from the base station with a local replica in the receiver. The CSI-RS may be used in the downlink and sidelink. CSI-RS may be used for channel state estimation, Reference Signal Received Power (RSRP) measurements for mobility and beam management, time / frequency tracking for modulation, etc. CSI-RS may be configured for individual UEs, but multiple users may share the same CSI-RS resource. The UE may identify CSI reports and transmit them in the uplink to the base station using the PUCCH or PUSCH. CSI reports may be carried in the sidelink MACCE. Primary Synchronization Signal (PSS) The Primary Synchronization Signal (PSS) and Secondary Synchronization Signal (SSS) may be used for radio frame synchronization. The Primary Synchronization Signal (PSS) and Secondary Synchronization Signal (SSS) may be used for cell search procedures during initial attach or for mobility purposes. The Sounding Reference Signal (SRS) may be used in the uplink for uplink channel estimation. Similar to the CSI-RS, the SRS may also serve as a QCL reference for other physical channels, which may be configured and transmitted in a quasi-colocated relationship with the SRS. The Sidelink PSS (S-PSS) and Sidelink SSS (S-SSS) may be used in the sidelink for sidelink synchronization.

[0050] 7 illustrates example Radio Resource Control (RRC) states and transitions between different RRC states in accordance with some aspects of one or more example embodiments of the present disclosure. 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-up, 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 transmit / receive data and / or voice calls. Once the RRC connection is established, the UE may be in the RRC connected state 710. The UE may transition from the RRC idle state 720 to the RRC connected state 710 or from the RRC connected state 710 to the RRC idle state 720 using an RRC connection establishment / release procedure 740.

[0051] 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 preserved by both the UE and the gNB. As a result, a fast state transition from the RRC inactive state 730 to the RRC connected state 710 may occur. The UE may transition from the RRC inactive state 730 to the RRC connected state 710 or from the RRC connected state 710 to the RRC inactive state 730 using the RRC connection resumption / deactivation procedure 76. 0. The UE may transition from the RRC inactive state 730 to the RRC idle state 720 using an RRC connection release procedure 750.

[0052] FIG. 8 illustrates an example frame structure and physical resources according to some aspects of one or more exemplary embodiments of the present disclosure. Downlink, uplink, or sidelink transmissions may be organized into a 10 ms time frame 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 in which the transmission occurs. The slot duration may be 14 symbols of normal cyclic prefix (CP) and 12 symbols of extended CP, and time may be scaled so that there are an integer number of slots within a subframe depending on the subcarrier spacing used. FIG. 8 illustrates a resource grid in the time and frequency domains. Each element of the resource grid, which contains one symbol in time and one subcarrier in frequency, is called a resource element (RE). A resource block (RB) may be defined as 12 consecutive subcarriers in the frequency domain.

[0053] In some examples, non-slot-based scheduling allows transmission of packets over a portion of a slot, e.g., 2, 4, or 7 OFDM symbols, which may also be referred to as minislots. 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., prioritized connections for URLLC in eMBB).

[0054] FIG. 9 illustrates exemplary component carrier configurations in different carrier aggregation scenarios in accordance with some aspects of one or more exemplary embodiments of the present disclosure. In carrier aggregation (CA), two or more component carriers (CCs) may be aggregated. A UE may simultaneously transmit and receive on one or more CCSs depending on its capabilities. CA may be supported for both contiguous and non-contiguous CCs within the same band or in different bands, as shown in FIG. 9. The gNG and the UE may communicate using a serving cell. The serving cell may be associated with at least one downlink CC (e.g., associated with only one downlink CC or associated with a downlink CC and an uplink CC). The serving cell may be a primary cell (PCell) or a secondary cell (SCell).

[0055] A 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 specify a desired timing advance setting and provide it to the UE. The UE may use the provided TA to specify the uplink transmission timing relative to the observed downlink receive timing for the UE.

[0056] In the RRC connected state, the gNB may be responsible for maintaining the timing advance to keep L1 synchronized. Serving cells with the same timing advance applied to the uplink and with the same timing reference cell are grouped into a Timing Advance Group (TAG). A TAG may contain at least one serving cell with an uplink configured. 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 cell, with the exception of shared spectrum channel access where in certain cases an SCell may also be used as a timing reference cell. For a secondary TAG, the UE may use any of the activated SCells of this TAG as a timing reference cell, and may use the PCell if not required. You can't change it unless you do.

[0057] Timing advance updates may be signaled by the gNB to the UE via MAC CE commands. Such a command may restart a per-TAG timer, which may indicate whether L1 can be synchronized or not. That is, if the timer is running, L1 may be considered synchronized; otherwise, L1 may be considered not synchronized (in which case uplink transmissions may only occur on the PRACH).

[0058] A UE with one timing advance capability for CA may simultaneously receive and / or transmit on 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 capabilities for CA may simultaneously receive and / or transmit on 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 and transmit on one CC corresponding to only one serving cell (one serving cell in one TAG).

[0059] The multi-carrier nature of the physical layer in the 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. During RRC connection establishment / re-establishment / handover, one serving cell (e.g., PCell) may provide NAS mobility information. Depending on the UE capabilities, SCells may be configured to form a serving cell set together with the PCell. The configured serving cell set for a UE may consist of one PCell and one or more SCells. Reconfiguration, addition, and removal of SCells are performed by RRC.

[0060] In a dual connectivity scenario, a UE may be configured with multiple cells including a Master Cell Group (MCG) for communication with a master base station, a Secondary Cell Group (SCG) for communication with secondary base stations, and two MAC entities, i.e., one MAC entity for the MCG for communication with the master base station and one MAC entity for the SCG for communication with the secondary base stations.

[0061] FIG. 10 illustrates exemplary bandwidth portion configuration and switching in accordance with some aspects of one or more exemplary embodiments of the present disclosure. A UE may be configured with one or more bandwidth portions (BWPs) 1010 on a component carrier. In some examples, one of the one or more bandwidth portions may be active at a time. The active bandwidth portion may define the UE's operating bandwidth within the cell's operating bandwidth. During initial access, an initial bandwidth portion 1020 identified from system information may be used until the UE's configuration within the cell is received. Through bandwidth adaptation (BA), for example, via BWP switching 1040, the UE's reception and transmission may be adjusted, rather than being as large as the cell's bandwidth. For example, the width may be commanded to change (e.g., to reduce during periods of low activity to conserve power), the location in the frequency domain may be moved (e.g., to increase scheduling flexibility), or the subcarrier spacing may be commanded to change (e.g., to enable different services). The first active BWP 1020 may be the active BWP at the time of RRC (re)configuration for the PCell or activation of the SCell.

[0062] For each downlink BWP or uplink BWP in the set of downlink BWPs or uplink BWPs, the UE may be provided with the following configuration parameters: : subcarrier spacing (SCS), cyclic prefix, number of common RBs and consecutive RBs, index within the set of downlink BWPs or uplink BWPs by their respective BWP-Ids, BWP-common parameter set and BWP-individual parameter set. A BWP can be associated with an OFDM numerology according to the subcarrier spacing and cyclic prefix configured for that BWP. For a serving cell, a UE can be provided with a default downlink BWP among the configured downlink BWPs. If a default downlink BWP is not provided to the UE, the default downlink BWP can be the initial downlink BWP.

[0063] A downlink BWP may be associated with a BWP inactivity timer. When 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. When 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 the initial downlink BWP.

[0064] 11 illustrates an exemplary four-stage contention-based and non-contention-based random access process in accordance with certain aspects of one or more exemplary embodiments of the present disclosure. FIG. 12 illustrates an exemplary two-stage contention-based and non-contention-based random access process in accordance with certain aspects of one or more exemplary embodiments of the present disclosure. The random access procedure can be triggered by various events, such as initial access from an RRC idle state, an RRC connection re-establishment procedure, arrival of downlink or uplink data during an RRC connected state when the uplink synchronization state is "unsynchronized," arrival of uplink data during an RRC connected state when PUCCH resources are unavailable 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, a request for other system information (SI) to establish time alignment for a secondary TAG, Beam Failure Recovery (BFR), and a sustained uplink Listen-Before-Talk (LBT) failure on the PCell.

[0065] Two types of random access (RA) procedures can be supported: four-stage RA with MSGA and two-stage RA with MSGA. Both types of RA procedures can support contention-based random access (CBRA) and contention-free random access (CFRA), as shown in Figures 11 and 12.

[0066] When initiating a random access procedure, the UE may select a random access type based on the network configuration. If CFRA resources are not configured, the UE may use the RSRP threshold to select between a two-stage RA type or a staged RA type. If CFRA resources for a four-stage RA type are configured, the UE may perform random access with the four-stage RA type. If CFRA resources for a two-stage RA type are configured, the UE may perform random access with the two-stage RA type.

[0067] MSG1 for the four-stage RA type may consist of a preamble for the PRACH. After transmitting MSG1, the UE may monitor a response from the network within a configured window. In the case of CFRA, a dedicated preamble for MSG1 transmission may be 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. In the case of CBRA, upon receiving a random access response, the UE may transmit MSG3 using the uplink grant scheduled in the random access response and monitor collision resolution as shown in FIG. 11. If collision resolution is unsuccessful after MSG3 (re)transmission, the UE may May revert to SG1 transmission.

[0068] The MSGA for the two-step RA type may include a PRACH preamble and a PUSCH payload. After transmitting the MSGA, the UE may monitor a response from the network within a configured window. In the case of CFRA, separate 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. In the case of CBRA, if collision resolution is successful upon receiving a network response, the UE may terminate the random access procedure shown in FIG. 12. However, if a fallback indication is received in the MSGB, the UE may perform transmission of MSG3 using the uplink grant scheduled in the fallback indication and monitor collision resolution. If collision resolution is unsuccessful after the MSG3 (re)transmission, the UE may revert to MSGA transmission.

[0069] 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 one or more exemplary embodiments of the present disclosure. An SS / PBCH block (SSB) may consist of primary and secondary synchronization signals (PSS, 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 in the center for the SSS, as shown in FIG. 13 . The possible time locations of the SSBs within a half-frame may be specified by the subcarrier spacing, and the period of the half-frame during which the SSBs are transmitted may be configured by the network. During a half-frame, different SSBs may be transmitted in different spatial directions (i.e., using different beams and across the entire cell coverage area).

[0070] The PBCH may be used to carry a Master Information Block (MIB) that the UE uses 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 to schedule the PDSCH carrying SIB1. In addition, the MIB may indicate Cell Barred status information. The MIB and SIB1 may be collectively referred to as Minimum System Information (SI), and SIB1 may be referred to as Remaining Minimum System Information (RMSI). The other System Information Blocks (SIBs) (e.g., SIB2, SIB3, ..., SIB10, and SIBpos) may be referred to as other SIs. Other SI may be broadcast periodically on the DL-SCH, broadcast on demand on the DL-SCH (e.g., upon request from UEs in RRC idle, RRC inactive, or RRC connected states), or sent individually on the DL-SCH to UEs in RRC connected state (e.g., upon request from UEs in RRC connected state if configured by the network, or when the UE has an active BWP and no common search space is configured).

[0071] FIG. 14 illustrates an exemplary SSB burst transmission according to some aspects of one or more exemplary embodiments of the present disclosure. The 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., SSB burst duration). During a contention-based random access process, the UE may perform a random access resource selection process, where the UE first selects an SSB and then selects an RA preamble. The UE may select an SSB with an RSRP higher than a configured threshold. In some embodiments, the UE may select any SSB if an SSB with an RSRP higher than a configured threshold is not available. The selection of the random access preamble The SSB may be associated with the SSB. After selecting the SSB, the UE may select a random access preamble from a set of random access preambles associated with the SSB and transmit the selected random access preamble to initiate the random access process.

[0072] 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 higher than 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 that is quasi-colocated with the selected CSI-RS.

[0073] In some embodiments, based on the UE's measurements of CSI-RS resources and the UE's CSI reporting, the base station may identify a Transmission Configuration Indication (TCI) state and indicate the TCI state to the UE, which may use the indicated TCI state for receiving downlink control information (e.g., via a PDCCH) or data (e.g., via a PDSCH). The UE may use the indicated TCI state to use an appropriate beam for receiving 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., a PDCCH or a PDSCH, respectively).

[0074] In some embodiments, a UE can be configured with a list of up to M TCI states using physical downlink shared channel (PDSCH) configuration parameters to decode the PDSCH according to the PDCCH detected in the DCI intended for the UE and a serving cell, where M may depend on the UE's capabilities. Each TCI-state can include parameters for configuring a QCL relationship between one or two downlink reference signals and a DM-RS port of the PDSCH, a DM-RS port of the PDCCH, or a CSI-RS port of a CSI-RS resource. The quasi-collocation relationship can be configured by one or more RRC parameters. The type of quasi-collocation corresponding to each DL RS can take one of the following values: 'QCL-TypeA': {Doppler shift, Doppler extension, mean delay, delay extension}, 'QCL-TypeB': {Doppler shift, Doppler extension}, 'QCL-TypeC': {Doppler shift, mean 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.

[0075] 15 illustrates example components of a user terminal and a base station in accordance with some aspects of one or more example embodiments of the present disclosure. In one embodiment, the example components of FIG. 15 may be considered to illustrate functional blocks of an example base station 1505. In other embodiments, the example components of FIG. 15 may be considered to illustrate functional blocks of an example user terminal 1500. Thus, the components illustrated in FIG. 15 are not necessarily limited to either a user terminal or a base station.

[0076] As shown in FIG. 15, an antenna 1510 can be used to transmit or receive electromagnetic signals. The antenna 1510 may include one or more antenna elements, which may enable various input-output antenna configurations, including multiple-input multiple-output (MIMO), multiple-input single-output (MISO), and single-input multiple-output (SIMO) configurations. In some embodiments, the antenna 1510 may implement a massive MIMO configuration using tens or hundreds of antenna elements. The antenna 1510 may also use other multi-antenna techniques, such as beamforming. In some examples, and depending on the capabilities of the UE 1500 and the type of the UE 1500 (e.g., a low-complexity UE), the UE 1500 may only support a single antenna.

[0077] The transceiver 1520 may communicate bidirectionally over a wireless link as described herein via the antenna 1510. For example, the transceiver 1520 may represent a wireless transceiver at a UE and may communicate bidirectionally with a wireless transceiver at a base station, or vice versa. The transceiver 1520 may include a modem for modulating packets and providing the modulated packets to the antenna 1510 for transmission, and for modulating packets received from the antenna 1510.

[0078] The memory 1530 may include RAM and ROM. The memory 1530 may store computer-readable, computer-executable code 1535, which includes instructions that, when executed, cause the processor to perform various functions described herein. In some embodiments, the memory 1530 may include, among other things, a Basic Input / Output System (BIOS), which may control basic hardware or software operations, such as interaction with peripheral components or devices.

[0079] 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 incorporated into the processor 1540. The processor 1540 may be configured to execute computer-readable instructions stored in a memory (e.g., memory 1530) to cause the UE 1500 or the base station 1505 to perform various functions.

[0080] A central processing unit (CPU) 1550 may perform the basic arithmetic, logic, control, and input / output (I / O) operations specified by computer instructions in memory 1530. The user terminal 1500 and / or base station 1505 may include other peripheral components, such as a graphics processing unit (GPU) 1560 and a global positioning system (GPS) 1570. The GPU 1560 is specialized circuitry that manipulates and modifies memory 1530 at high speed to accelerate processing performance of the user terminal 1500 and / or base station 1505. The GPS 1570 may be used to enable location-based services and other services based, for example, on the geographic location of the user terminal 1500.

[0081] In some examples, MBS services may be realized via single-cell transmission. The MBS may be transmitted within the coverage of a single cell. One or more multicast / broadcast control channels (e.g., MCCHs) and one or more multicast / broadcast data channels (e.g., MTCHs) may be mapped on the DL-SCH. Scheduling may be performed by the gNB. The transmission of the multicast / broadcast control channel and the multicast / broadcast data channel may be performed by the P The RNTI for each logical channel on the DCCH may be indicated. In some examples, a one-to-one mapping between a service identifier, such as a temporary mobile group identifier (TMGI), and a RAN-level identifier, such as a group identifier (G-RNTI), may be used for reception of the DL-SCH to which the multicast / broadcast data channel may be mapped. In some examples, a DL-SCH associated with a multicast / broadcast control channel and / or multicast / broadcast data channel transmission may be used, and HARQ or RLC retransmissions may not be used, and / or RLC Unacknowledged Mode (RLC UM) may be used. In other examples, some feedback (e.g., HARQ feedback or RLC feedback) may be used for transmissions over the multicast / broadcast control channel and / or multicast / broadcast data channel.

[0082] In some examples, the following scheduling information may be provided on the multicast / broadcast control channel for the multicast / broadcast data channel: scheduling cycle for the multicast / broadcast data channel, reception period for the multicast / broadcast data channel (e.g., the period the UE waits to receive PDCCHs after waking up from DRX), multicast / broadcast data channel inactivity timer (e.g., the period the UE waits to successfully decode a PDCCH indicating the DL-SCH to which this multicast / broadcast data channel is mapped, failing which it will re-enter DRX).

[0083] In some examples, one or more UE identifiers may be associated with the MBS transmission. The one or more identifiers may include at least one of one or more first RNTIs identifying a multicast / broadcast control channel transmission and one or more second RNTIs identifying a multicast / broadcast data channel transmission. The one or more first RNTIs identifying a multicast / broadcast control channel transmission may include a single-cell RNTI (SC-RNTI, although other names may be used). The one or more second RNTIs identifying a multicast / broadcast data channel transmission may include a G-RNTI (nG-RNTI or other names may be used).

[0084] In some examples, one or more logical channels may be associated with MBS transmission. The one or more logical channels may include a multicast / broadcast control channel. The multicast / broadcast control channel may be a point-to-multipoint downlink channel used to transmit MBS control information from the network to the UEs. This channel may be used by UEs that receive or are interested in receiving the MBS. The one or more logical channels may include a multicast / broadcast data channel. This channel may be a point-to-multipoint downlink channel for transmitting MBS traffic data from the network.

[0085] In some examples, the UE may use a procedure to inform the RAN that the UE is receiving or interested in receiving MBS service via an MBS radio bearer, and if so, inform the 5G RAN about the priority of MBS versus unicast reception or reception of the MBS service. The UE may transmit a message (e.g., an MBS Interest Indication Message) to inform the RAN that the UE is receiving / interested in receiving, or no longer receiving / not interested in, the MBS service. The UE may transmit the message in response to one or more messages from the network indicating, for example, one or more MBS service area identifiers for the current and / or neighboring carrier frequencies. The transmission may be based on receiving a SIB message or a unicast RRC message.

[0086] In some examples, a UE may consider an MBS service to be part of an MBS service of interest if the UE can receive the MBS service (e.g., via a single-cell point-to-multipoint mechanism), and the UE may be configured to receive or indicate, via a bearer associated with the MBS service, information that the MBS service is of interest to the UE. In yet another example, the UE may identify or transmit information that one session of this service is ongoing or about to start. In yet another example, the UE may receive or indicate information that at least one of one or more MBS service identifiers indicated by the network is of interest to the UE.

[0087] In some examples, control information for receiving MBS services may be provided on a specific logical channel (e.g., the MCCH). The MCCH may carry one or more configuration messages indicating ongoing MBS sessions, as well as (corresponding to) information regarding when each session is scheduled, such as the scheduling period, scheduling window, and starting offset. The one or more configuration messages may provide information regarding neighboring cells transmitting MBS sessions that may be ongoing on the current cell. In some examples, a UE may receive one MBS service at a time or multiple MBS services in parallel.

[0088] In some examples, MCCH information (e.g., information sent in messages transmitted on the MCCH) may be transmitted periodically using a configurable repetition period, and the MCCH transmission (and its associated radio resources and MCS) may be indicated on the PDCCH.

[0089] In some examples, modification of MCCH information may be performed in a specific radio frame / subframe / slot and / or a modification period may be used. For example, within a modification period, the same MCCH information may be transmitted multiple times as defined by its scheduling (which is based on a recurrence period). The boundaries of the modification period may be defined by an SFN value of SFN mod m=0, where m is the number of radio frames that comprise the modification period. The modification period may be configured by SIB or by RRC signaling.

[0090] In some examples, when the network changes (part of) the MCCH information, it may notify UEs about the change in the first subframe / slot that can be used for MCCH transmission within a recurrence period. Upon receiving the change notification, UEs interested in receiving MBS services may acquire the new MCCH information starting from the same subframe / slot. The UE may apply the previously acquired MCCH information until the UE acquires the new MCCH information.

[0091] In an example, the system information block (SIB) may include information necessary to acquire transmissions related to the control information of the MBS, such as one or more discontinuous reception (DRX) parameters for monitoring scheduling information for transmissions related to the control information of the MBS, a scheduling period and offset for scheduling information for transmissions related to the control information of the MBS, a modification period for modifying content of communications related to the control information of the MBS, repetition information for repetition of transmissions related to the control information of the MBS, etc.

[0092] In one example, an information element (IE) may provide configuration parameters indicating, for example, a list of ongoing MBS sessions transmitted over one or more bearers for each MBS session, one or more associated RNTIs (e.g., G-RNTI, although other names may be used), and scheduling information. X) (e.g., an Inactivity Timer or an On Duration Timer), an RNTI for scrambling the scheduling and transmission of a multicast / broadcast traffic channel (e.g., MTCH, although other names may be used), one or more power management control parameters, one or more scheduling periodicity and / or offset values ​​for one or more MBS traffic channels, information regarding a list of neighboring cells, etc.

[0093] In one example, a UE may monitor a set of PDCCH candidates for configured monitoring occasions in one or more configured Control Resource Sets (CORESETs) with corresponding search space configurations. A CORESET may include a set of physical resource blocks (PRBs) that are 1 to 3 OFDM symbols in length. Resource units, Resource Element Groups (REGs), and Control Channel Elements (CCEs) may be defined within a CORESET, with each CCE including a set of REGs. A control channel may be formed by a collection of CCEs. Different code rates for the control channel may be achieved by aggregating different numbers of CCEs. Interleaved and non-interleaved CCE-REG mapping may be supported within a CORESET.

[0094] In some examples, an information element (IE) MeasIdleConfig may be used to convey information to the UE regarding measurements that are requested to be performed during RRC_IDLE or RRC_INACTIVE. Example parameters of the MeasIdleConfig IE may include the following parameters: Other parameters for measurements related to MBS services / sessions while in RRC IDLE or RRC INACTIVE state may be used in addition to or instead of one or more of the following parameters. These parameters include:

[0095] The parameter absThreshSS-BlocksConsolidation may indicate a threshold for consolidation of L1 measurements by RS index. The parameter beamMeasConfigIdle may indicate the beam level measurement configuration. The parameter carrierFreq may indicate the NR carrier frequency used for measurements during RRC_IDLE or RRC_INACTIVE. The parameter carrierFreqEUTRA may indicate the E-UTRA carrier frequency used for measurements during RRC_IDLE or RRC_INACTIVE. The parameter deriveSSB-IndexFromCell may indicate whether the UE can derive the SSB indexes of all neighboring cells on that frequency using the timing of any detected cell on that frequency. When this field is set to a true value, the UE may assume alignment of system frame numbers (SFNs) and frame boundaries across cells on neighboring frequencies. The parameter frequencyBandList may indicate a list of frequency bands to which the NR idle / inactive measurement parameters may apply. The UE may select the first listed band that it supports in the frequencyBandList field to represent the NR neighbor carrier frequency. The parameter includeBeamMeasurement may indicate whether the UE may include beam measurements in NR idle / inactive measurement results. The parameter maxNrofRS-IndexesToReport may indicate the maximum number of beam indices to include in idle / inactive measurement results. The parameter measCellListEUTRA may indicate a list of E-UTRA cells that the UE is asked to measure and report for idle / inactive measurements. The parameter measIdleCarrierListNR may indicate the NR carriers to be measured during RRC_IDLE or RRC_INACTIVE. The parameter measIdleDuration may indicate the NR carriers to be measured during RRC_IDLE or RRC_INACTIVE. The parameter, nrofSS-BlocksToAverage, may indicate the duration for performing idle / inactive measurements during IVE. The parameter, nrofSS-BlocksToAverage, may indicate the number of SS blocks to be averaged for cell measurement derivation. The parameter, qualityThreshold, may indicate the quality threshold for reporting measurement cells for idle / inactive NR measurements. The parameter, qualityThresholdEUTRA, may indicate the quality threshold for reporting measurement cells for idle / inactive E-UTRA measurements. The parameter, reportQuantities, may indicate which measurement quantities the UE is requested to report in an idle / inactive measurement report. The parameter, reportQuantitiesEUTRA, may indicate which E-UTRA measurements the UE is requested to report in an idle / inactive measurement report. The parameter, reportQuantityRS-Indexes, may indicate which information per beam index the UE is to include in the NR idle / inactive measurement results. The parameter, smtc, may indicate the measurement timing configuration for inter-frequency measurements. The parameter, ssbSubcarrierSpacing, may indicate the subcarrier spacing of SSB. The parameter ssb-ToMeasure may indicate the SS block set to be measured within the SMTC measurement time. The parameter ss-RSSI-Measurement may indicate the SSB-based RSSI measurement configuration. The parameter validityAreaList may indicate a list of frequencies and, optionally, a list of cells for each frequency, on which the UE needs to perform measurements during RRC_IDLE and RRC_INACTIVE.

[0096] In some examples, a SIB (e.g., SIB11) may contain information about idle / inactive measurements. The parameter / IE measIdleConfigSIB may indicate the measurement configuration that the UE stores and uses during RRC_IDLE or RRC_INACTIVE.

[0097] In some examples, in RRC_IDLE state, the UE may not be registered with a particular cell, and therefore the UE may not have received AS context and other information from the network. The network may initiate an RRC connection release procedure to transition an RRC_CONNECTED UE to RRC_IDLE state. The UE may wake up periodically (according to the configured DRX cycle) and monitor for paging messages from the network. The network may contact UEs in RRC_IDLE state through paging messages and notify UEs in RRC_IDLE of system information changes and other indications through short messages. Both paging messages and short messages may be indicated by the P-RNTI on the PDCCH. Paging messages may be transmitted on the PCCH, and short messages may be transmitted on the PDCCH.

[0098] In some examples, when in RRC_IDLE, the UE may monitor the paging channel for paging from the CN. In the RRC_INACTIVE state, the UE may monitor the paging channel for paging from the RAN. The UE may not monitor the paging channel continuously. If a UE in RRC_IDLE or RRC_INACTIVE may monitor the paging channel during a paging occasion (PO) according to the DRX cycle, paging DRX may not be used.

[0099] In some examples, in the RRC IDLE state, the UE may manage mobility through cell (re)selection based on network configuration. The UE may perform neighbor cell measurements for cell (re)selection.

[0100] In some instances, when transitioning from RRC_CONNECTED or RRC_INACTIVE to RRC_IDLE, the UE may camp on a cell as a result of cell selection according to the frequency assigned by RRC in the state transition message. do.

[0101] In some examples, in the RRC_IDLE state, the UE may not transmit on the uplink except for the PRACH, which is initiated when the UE wishes to transition to the RRC_CONNECTED state or request on-demand system information.

[0102] In some examples, the RRC_INACTIVE state may be used to reduce the network signaling load and latency involved in transitioning to the RRC_CONNECTED state. In the RRC_INACTIVE state, the AS context may be retained by both the UE and the gNB. The state transition from the INACTIVE state to the CONNECTED state is initiated by the RRC The state transition from the IDLE state to the RRC connected state may be faster. In some examples, the core network connection may be maintained in an RRC inactive state (e.g., the UE may remain in CM-CONNECTED).

[0103] In some examples, a UE in RRC inactive state may wake up periodically (according to a configured DRX cycle) and monitor for paging messages from the network. The network may contact UEs in RRC_INACTIVE state through paging messages and notify RRC_INACTIVE UEs of system information changes and other indications through short messages. Both paging messages and short messages may be indicated by the P-RNTI on the PDCCH and may be transmitted on the PCCH and PDCCH, respectively.

[0104] In some embodiments, the UE may monitor the paging channel for CN paging using 5G-S-TMSI and RAN paging using the full RNTI (inactive RNTI). The I-RNTI may be used to identify a suspended UE context for a UE in RRC_INACTIVE state. The network may assign the I-RNTI to the UE when transitioning from RRC_CONNECTED to RRC_INACTIVE state in an RRCRelease message within SuspendConfig.

[0105] In some examples, in the RRC_INACTIVE state, the UE may not transmit on the uplink except for the PRACH, which is initiated when the UE wants to move to the RRC_CONNECTED state (send an RRCResumeRequest) or request on-demand system information.

[0106] In some examples, the gNB may transition the UE from RRC_CONNECTED to RRC_INACTIVE state by sending an RRCRelease message with suspendConfig.

[0107] The suspendConfig field may provide the UE with the configuration required for the RRC_INACTIVE state and may indicate the full I-RNTI, short I-RNTI, ran-NotofocationAreaInfo, ran-PagingCycle, values ​​of the timers that trigger periodic RNA updates, etc.

[0108] In some embodiments, resumption of a suspended RRC connection may be initiated by upper layers when the UE transitions from RRC_INACTIVE to RRC_CONNECTED state, by the RRC layer to perform an RNA update, or by RAN paging from the NG-RAN. The RRC connection resumption procedure may reactivate AS security and re-establish signaling radio bearers (SRB(s)) and data radio bearers (DRB(s)).

[0109] 16A-16E, in response to a request for RRC connection resumption, the network may resume the suspended RRC connection and send the UE to RRC_CONNECTED, or may reject the resumption request and send the UE to RRC_INACTIVE (e.g., using a waiting timer), or may again suspend the RRC connection and send the UE to RRC_INACTIVE, or may release the RRC connection and send the UE to RRC_IDLE, or may instruct the UE to initiate NAS-level recovery (in this case, the network may send an RRC SETUP message). In the first scenario (FIG. 16A), the RRC connection resumption may be successful (e.g., transition from RRC_INACTIVE to RRC_CONNECTED). In the second scenario (FIG. 16B), the RRC connection resumption may fall back to RRC connection establishment (e.g., transition from RRC_INACTIVE to RRC_CONNECTED). In a third scenario (Figure 16C), the network may release the RRC connection after the RRC connection resumes (e.g., transition from RRC_INACTIVE to RRC_IDLE). In a fourth scenario (Figure 16D), the network may suspend the RRC connection after the RRC connection resumes (e.g., transition from RRC_INACTIVE to RRC_INACTIVE). In a fifth scenario (Figure 16E), the network may reject the RRC connection after the RRC connection resumes (e.g., transition from RRC_INACTIVE to RRC_INACTIVE). The RRC connection resume procedure may trigger a random access procedure. For example, the UE may send an RRCResumeRequest(UL CCCH) message with MSG3 or MsgA.

[0110] In some examples, the ResumeCause field may indicate one of the following or may indicate other parameters associated with the MBS service and / or MBS service continuity: emergency, highPriorityAccess, mt-Access, mo-Signalling, mo-Data, mo-VoiceCall, mo-VideoCall, mo-SMS, rna-Update, mps-PriorityAccess, or mcs-PriorityAccess.

[0111] Upon receiving a resume request from the UE, the network may send an RRCResume (DCCH) to resume the suspended RRC connection. The UE may acknowledge successful completion of the RRC connection resumption procedure by sending an RRCResumeComplete (DCCH) message.

[0112] In some examples, in the RRC_INACTIVE state, the UE may remain CM-CONNECTED and move within the area configured by the NG-RAN (RAN Notification Area (RNA)) without notifying the NG-RAN. In this state, the last serving gNB node may maintain the UE context and the UE-associated NG connection with the serving AMF and UPF. When the last serving gNB receives downlink data from the UPF or downlink UE-associated signaling from the AMF, it may page the cell corresponding to the RNA and send Xn-AP RAN paging to the neighboring gNB(s) if the RNA includes the cells of the neighboring gNB(s).

[0113] In some examples, a UE in RRC_INACTIVE state may be configured by the last serving NG-RAN node (e.g., in an RRCRelease message via suspendConfig) with an RNA in the following state: The RNA may cover one or more cells and be contained within the CN registration area. A RAN-based notification area update (RNAU) may be sent periodically by the UE. In some examples, an RNAU may be sent when the UE reselects a cell that does not belong to the configured RNA.

[0114] In some examples, during the UE's transition to RRC_INACTIVE, the NG-RAN node may configure the UE with a periodic RNA update timer value (e.g., t380). When this periodic timer expires, the UE may initiate an RRC connection resumption procedure with resumeCause set to rna-update.

[0115] In some examples, a UE in RRC_INACTIVE state may initiate an RNA update procedure (e.g., resumeCaus is set to rna-Update) when it moves out of the configured RNA, i.e., when the serving cell may not belong to the configured ran-NotificationAreaInfo.

[0116] In some examples, upon receiving an RNA update request from the UE, the receiving gNB may trigger an Xn-AP Retrieve UE Context procedure to retrieve the UE context from the last serving gNB and may decide whether to return the UE to an RRC_INACTIVE state, move the UE to an RRC_CONNECTED state, or send the UE to RRC_IDLE.

[0117] In some examples, when a UE accesses a gNB other than the last serving gNB, the receiving gNB may trigger an Xn-AP Retrieve UE Context procedure to retrieve the UE context from the last serving gNB. If the UE accesses a gNB other than the last serving gNB and the receiving gNB does not find a valid UE context, the receiving gNB may perform a new RRC connection establishment rather than resuming the previous RRC connection.

[0118] In some examples, Multicast and Broadcast Services (MBS) may use a Single Cell Single Cell Point-to-Multipoint (SC-PTM) framework. SC-PTM may be used for eMBMS services, Mission Critical Push-to-Talk (MCPTT), Internet of Things (IoT), and Vehicle-to-Everything (V2X). Exemplary solutions for service continuity and handover procedures do not consider UE and service mobility of MBS services / sessions for UEs in RRC inactive or RRC idle states. It is necessary to maintain service continuity and mobility of MBS services for UEs in RRC idle and RRC inactive states. Exemplary embodiments provide service continuity and mobility of MBS services / sessions for UEs in RRC idle and RRC inactive states.

[0119] Given the breadth of MBS services and the emphasis on power saving in 5G, it is also important to maximize commonality with connected state mobility while preserving MBS service continuity and mobility for idle and inactive UEs. In some examples, such mobility support for idle / inactive UEs may not be required for all MBS services or supported in the same way for all UEs. In some examples, the level of mobility support for MBS services may be configurable per MBS service and / or per UE.

[0120] In some examples, for some MBS services, e.g., services with low duty cycle, UEs may receive MBS data in idle / inactive states as well as connected states even if they move to other cells. This may be a QoS parameter, which may be configured per service and / or per user.

[0121] In some instances, supporting service continuity with mobility may be possible only for UEs in RRC inactive state or only for UEs in RRC idle state. It may be enabled for UEs in both RRC inactive and RRC idle states.

[0122] In some examples, support of Service Continuity (SC) for MBS services in general and for UEs in idle / inactive state may be a QoS parameter that may be configured per service and / or per UE.

[0123] In some examples, for MBS with SC options, the geographic area where such service can be expected by a UE can be configured by application layer signaling. UEs can determine whether their targeted MBS service is offered in a neighboring cell using their geolocation or based on configuration information received from the serving / selected (target) cell.

[0124] An exemplary process for MBS service continuity in an RRC inactive or RRC idle state is shown in Figure 17. In some examples, the UE may be configured with measurements and trigger events, and the UE may indicate to the RAN the need for MBS service continuity when the UE moves to a target cell while in an RRC idle or RRC inactive state.

[0125] In some examples, UEs in RRC inactive / idle state may be configured with triggers to initiate MBS service continuity MBS-SC measurements and MBS service continuity processes. In some examples, measurement threshold types and / or events may be MBS service continuity specific. In some examples, threshold types and / or events may have different values ​​configured for cell (re)selection in RRC idle or RRC inactive states.

[0126] Exemplary options for MBS service continuity in an RRC inactive state or an RRC idle state are shown in FIG. 18. In some examples, if the UE determines that its MBS service continuity requires action by the RAN, it may initiate a procedure, which may or may not require the UE to return to a connected state. In some examples (e.g., options in FIG. 18), for a UE in an RRC inactive / idle state, based on confirming an MBS SC trigger, the UE may return to an RRC connected state and use a connected state mobility procedure for MBS H0 with the target cell. In some examples (e.g., options in FIG. 18), based on confirming an MBS SC trigger, a UE in an RRC inactive state may send an update to the RAN, for example, based on a RAN Notification Area (RNA) Update in the RRC Resume Request, or perform other procedures indicating its transition to the target cell while remaining in the RRC inactive state. In some examples, this process may allow such a UE's MBS context, as part of the UE's RAN context, to be shared with the target cell without the UE returning to a connected state. If the MBS configuration, e.g., BWP, subframe, slot time / format, etc., is different in the target cell, such information may be included in the RRC signaling returned to the UE, e.g., as part of a Suspend Indication message. In some examples (e.g., option c in Figure 18), a UE in RRC Inactive or RRC Idle state may, based on identifying an MBS SC trigger, send an update using RACH-based signaling to indicate to the network that the UE is moving out of the source cell towards the target and the MBS service it is receiving. Such signaling may reuse message A of the two-step RACH or message 3 of the four-step RACH procedure. Similar to option b, based on receiving this RACH signal, the RAN may send an RRC message, e.g., message B of the two-step RACH process or message 3 of the four-step RACH procedure. A pre-RACH process message may be sent to the UE, which contains information necessary for the UE to identify the MBS service in the target cell. A two-step RACH procedure may more efficiently reduce signaling, where message A from the UE may contain several identifiers for the UE and the target MBS service, and message B from the RAN may contain the MBS configuration of the UE-selected service in the target cell.

[0127] In some examples, the UE may initiate signaling with the source cell, and the source cell may request an MBS configuration for the target cell. The source cell may receive the MBS configuration for the target cell and transmit the MBS configuration for the target cell to the UE. In some examples, the UE may first initiate signaling with the target cell, and the target cell may obtain the UE's MBS context from the source cell. The UE may continue to receive its MBS data during the transition.

[0128] In the exemplary embodiment shown in FIG. 19, the UE may be in an RRC inactive or RRC idle state. The UE may transition from the RRC connected state to the RRC inactive or RRC idle state based on receiving an RRC message (e.g., an RRC release message) indicating the release of the RRC configuration or suspending the RRC configuration. For example, the suspension configuration information in the RRC release message may identify the suspended UE context in the RRC inactive state and / or indicate one or more RNTIs for receiving paging information: RAN notification area information, a paging cycle for RAN-initiated paging, one or more timers for UE operation during the RRC inactive state, etc. A UE transitioning to the RRC inactive state may retain the UE context, and the last serving gNB may retain the UE context. In some examples, a second gNB may request the UE context from the last serving gNB (e.g., the last serving gNB before transitioning to the RRC inactive state), and the second gNB may receive the UE context from the last serving gNB using Xn signaling. In some examples, the second gNB may receive a UE context associated with the MBS service from the gNB that last provided the service.

[0129] When in an RRC idle state or an RRC inactive state, the UE may receive a broadcast message (i.e., a system information block (SIB) message such as SIB11) containing measurement configuration parameters. For example, the broadcast message (e.g., a SIB message, e.g., SIB11) may include a MeasIdleConfig information element or a MeasIdleConfigSIB information element indicating one or more thresholds for L1 measurements, beam level configuration parameters, carrier frequencies to be used for measurements during the RRC IDLE or RRC INACTIVE state, a list of frequency bands to which the idle / inactive measurement parameters apply, one or more parameters indicating whether the UE may include beam measurements in NR idle / inactive measurement results, the duration for performing idle / inactive measurements during RRC IDLE or RRC INACTIVE, the number of SS blocks to average for cell measurement derivation, one or more subcarrier spacing parameters, etc.

[0130] The UE may identify a service continuity trigger (e.g., the need for (re)selection of a new desired cell) for one or more MBS services / sessions based on the measurement configuration parameters. For example, the service continuity trigger may indicate the need for handover to a target cell for at least one or more MBS services / sessions. For example, the UE may identify the service continuity trigger by comparing a value (e.g., an average) identified based on measuring one or more synchronization signals / PBCH blocks (SSBs) with a value (e.g., an average) identified based on measuring one or more SSBs (e.g., reference signal reference power (RSRP) and / or received signal received quality (RSRQ) of one or more SSBs). In some examples, the service continuity trigger may be specific to the MBS service, e.g., thresholds and / or other parameters associated with identifying the service continuity trigger may be specific to the MBS service and may be different for other services / sessions (e.g., unicast services / sessions). In some examples, the service continuity trigger may be specific to the MBS service, e.g., thresholds and / or other parameters associated with identifying the service continuity trigger may be different for different MBS services. In some examples, the service continuity trigger may be independent of the UE's ongoing service / session and may be UE-specific and not service / session-specific.

[0131] The UE may initiate a random access process in response to identifying a service continuity trigger for one or more MBS services / sessions. In some examples, a random access preamble used by the UE during a random access process (e.g., a random access process by a UE in an RRC inactive and / or RRC idle state) may indicate that the random access process is associated with an MBS service (e.g., service continuity for the MBS service / session). For example, a gNB serving a cell (e.g., a cell on which the UE is camped) or a target cell at which the random access preamble is transmitted may identify, based on the selected random access preamble, that the random access process is associated with an MBS service (e.g., MBS service continuity).

[0132] A group of pre-configured / configured random access preambles may be associated with an MBS service / session. The UE may transmit a first message based on a random access process, which indicates a request for MBS configuration parameters associated with one or more MBS services via the target cell. For example, the UE may transmit the first message based on Msg3 of a four-step random access process or MsgA of a two-step random access process. The first message may include one or more service identifiers (e.g., Mobile Group Identifiers (TMGIs)) that indicate MBS services that the UE is currently receiving from the cell on which it is currently camped or MBS services that the UE is interested in receiving from the target cell (e.g., MBS services for which service continuity is required). In some examples, a quality of service (QoS) associated with an MBS service / session (e.g., an MBS bearer) may indicate whether the MBS service / session requires service continuity (e.g., service continuity in idle and / or inactive states), and the UE and / or gNB may consider the QoS requirements of the MBS bearer or admission control by the target cell in transmitting the first message. The first message may include one or more fields, and one or more values ​​of the one or more fields are associated with the identified service continuity trigger and / or the need for service continuity for one or more MBS services. For example, the one or more fields may include a cause field indicating a cause for transmitting the first message. For example, the first message may be transmitted during another procedure and / or for other reasons, and the value of the cause field may indicate the cause for transmitting the first message. For example, if the UE is in an RRC inactive state, the first message may be an RRC resume request message, and the value of the cause field (e.g., the resume cause field) indicates that the cause of the first message transmission is for service continuity associated with one or more MBS services.The value of the cause field may indicate that the cause of the first message transmission is for service continuity associated with one or more MBS services while remaining in an RRC inactive state.

[0133] In response to transmitting the first message, the UE may use the target cell to configure MBS settings and / or receive data associated with the MBS service. In a four-step random access process, receiving MBS configuration parameters and / or information necessary to receive data associated with an MBS service using the target cell may be Msg4. In a two-step random access process, receiving MBS configuration parameters and / or information necessary to receive data associated with an MBS service using the target cell may be MsgB. In some examples, the UE may receive received MBS configuration parameters and / or information necessary to receive data associated with an MBS service from a cell on which the UE is currently camped. In some examples, the UE may receive received MBS configuration parameters and / or information necessary to receive data associated with an MBS service from the target cell.

[0134] The UE may receive information necessary to receive MBS configuration parameters and / or data associated with MBS services using the target cell as part of an RRC rejection message indicating to remain in an RRC inactive / idle state. For example, the RRC rejection message may include a suspend config information element indicating to remain in / transition to an RRC inactive state and including information necessary to receive MBS configuration parameters and / or data associated with MBS services using the target cell. In some examples, the information necessary to receive MBS configuration parameters and / or data associated with MBS services using the target cell may indicate and / or include service identifiers (e.g., TMGIs, etc.) of one or more MBS services provided by the target cell and / or may indicate the target cell or one or more MBS services allowed by the target cell. The allowed MBS services may be a subset of the MBS services indicated / requested by the first message. In some examples, the MBS configuration parameters and / or information necessary for receiving data associated with the MBS service using the target cell may include first configuration parameters for receiving control information for receiving MBS data from the target cell (e.g., via an MCCH). The first configuration parameters may include scheduling information for receiving the control information (e.g., periodicity of control information transmission by the target cell, etc.). In some examples, the MBS configuration parameters and / or information necessary for receiving data associated with the MBS service using the target cell may include a BWP identity of the target for receiving control information and / or data for the MBS service, a numerology associated with the MBS service (e.g., a numerology for MBS data / control reception), a control resource set (CORESET) for receiving scheduling information for the MBS data / control, etc.

[0135] The UE may receive data associated with the MBS service via the target cell using the MBS configuration parameters and / or information. The UE may remain in an RRC idle state or an RRC inactive state and may not transition to an RRC connected state.

[0136] In an embodiment, a user equipment (UE) in a radio resource control (RRC) state may receive a broadcast message including measurement configuration parameters, which may be one of an RRC inactive state and an RRC idle state. The UE may identify a service continuity trigger for one or more multicast broadcast service (MBS) services based on the measurement configuration parameters. In response to identifying the service continuity trigger for the one or more MBS services, the UE may initiate a random access process, which may include transmitting a first message indicating a request for MBS configuration parameters associated with the one or more MBS services via the target cell. The UE may receive a request for the one or more MBS configuration parameters based on transmitting the first message. The UE may then select one or more MBS services via the target cell while remaining in the RRC state based on the MBS configuration parameters. Associated data may be received.

[0137] In some embodiments, the broadcast message may be a system information block (SIB) message.

[0138] In some embodiments, the measurement configuration parameters may include one or more of: one or more thresholds, one or more carrier frequencies for measurements, one or more frequency band lists, one or more associated measurement parameters, one or more measurement cell lists, and the number of synchronization signal blocks (SSBs) for cell measurement derivation.

[0139] In some embodiments, identifying a service continuity trigger may be based on measuring one or more SSBs and comparing the received signal strength of the one or more SSBs to one or more thresholds.

[0140] In some embodiments, the first message may include a cause field, where a value of the cause field includes at least one of: that the first message was sent due to a service continuity trigger; and that the first message was sent to request MBS configuration parameters.

[0141] In some embodiments, the UE may be in an RRC inactive state, the first message may be an RRC resume request message, and values ​​of one or more fields in the RRC resume request message indicate a request for one or more MBS configuration parameters while remaining in the RRC inactive state. In some embodiments, the one or more fields may include a resume cause field. In some embodiments, receiving the one or more MBS configuration parameters may be via an RRC rejection message indicating to remain in the RRC inactive state.

[0142] In some embodiments, the one or more MBS configuration parameters may include one or more first parameters for receiving, via the target cell, control information associated with the one or more MBS services.

[0143] In some embodiments, the one or more MBS configuration parameters may include at least one of a bandwidth portion identifier, a control resource set, and a numerology associated with the one or more MBS services.

[0144] In some embodiments, the first message may include one or more service identifiers associated with one or more MBS services provided by the current cell on which the UE is camped. In some embodiments, the one or more MBS configuration parameters may include one or more first service identifiers of the one or more MBS service identifiers, the one or more first service identifiers being provided by the target cell.

[0145] In some embodiments, the quality of service associated with an MBS bearer associated with an MBS service of one or more MBS services may indicate a service continuity requirement level for the MBS bearer.

[0146] In some embodiments, the random access preamble transmitted during the random access process may indicate that the random access process is associated with MBS service continuity.

[0147] In some embodiments, transmitting the first message comprises a four-step random In some embodiments, receiving one or more MBS configuration parameters may be via message 4 of a four-step random access process.

[0148] In some embodiments, sending the first message may be via message A of a two-step random access process. In some embodiments, receiving the one or more MBS configuration parameters may be via message B of a two-step random access process.

[0149] In some embodiments, the UE may receive an RRC release message indicating a transition to an RRC inactive state or an RRC idle state, where the RRC release message may include one or more MBS service continuity parameters. In some embodiments, the RRC release message ma includes a suspend config information element, which indicates a transition to an RRC inactive state and includes one or more MBS service continuity parameters. In some embodiments, sending the first message may be based on the one or more MBS service continuity parameters.

[0150] The example blocks and modules described in connection with various example embodiments in this disclosure 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 a general-purpose processor 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 using a DSP core, or any other such configuration).

[0151] 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 from a computer-readable medium for execution of these functions. Other examples of implementation of the functions disclosed herein are also within the scope of this disclosure. Performance of the functions may be via physically co-located elements or distributed elements (e.g., at various locations), including distribution such that portions of the functions are executed at different physical locations.

[0152] Computer-readable media include, but are not limited to, non-transitory computer storage media. Non-transitory storage media can 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. Non-transitory media can be used to carry or store desired program code means (e.g., instructions and / or data structures) that can be accessed by a general-purpose or special-purpose computer or by a general-purpose or special-purpose processor. In some examples, software / program code can be transmitted from a remote resource (e.g., a website, a server, etc.) over a coaxial cable, fiber optic cable, twisted pair, digital subwoofer, or other suitable storage medium. The information may be transmitted using wireless technologies such as digital subscriber line (DSL), infrared, radio, and microwave. In such examples, coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included within the definition of media. Combinations of the above examples are also included within the scope of computer-readable media.

[0153] As used in this disclosure, the use of the word "or" in a list of items indicates an inclusive list. Lists of items may be accompanied by phrases such as "at least one of" or "one or more of." For example, a list of at least one of A, B, or C includes A or B or C or AB (i.e., A and B) or AC or BC or ABC (i.e., A, B, and C). Also, as used in this disclosure, when a list of conditions is accompanied by the phrase "based on," it is to be understood as "based at least in part" on those conditions, rather than "based only on" those conditions. For example, a result described as "based on condition A" could also be based on both condition A and condition B without departing from the scope of this disclosure.

[0154] As used herein, the terms "comprise," "include," or "contain" are used interchangeably, may have the same meaning, and are intended to be inclusive and open-ended. The term "comprise," "include," or "contain" may be used in conjunction with a list of elements to indicate that at least all of the elements listed in the list are present, but that other elements not in the list may also be present. For example, if A contains B and C, then both {B, C} and {B, C, D} are within the scope of A.

[0155] The present disclosure describes exemplary configurations in connection with the accompanying drawings, which do not necessarily represent all possible implementations or all configurations falling within the scope of the present disclosure. The term "exemplary" should not be interpreted as "preferred" or "advantageous over other examples," but rather as "an example, instance, or example." Upon reading this disclosure, including the description of the embodiments and the drawings, those skilled in the art will recognize that the technology disclosed herein may be implemented using alternative embodiments. Those skilled in the art will recognize that specific features of these embodiments, or of the embodiments described herein, may be combined to arrive at yet another embodiment for practicing the technology described in the present disclosure. Therefore, 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.

[0156] Clause 1. A method for maintaining service continuity comprises: receiving, by a user equipment (UE) in a radio resource control (RRC) state, a broadcast message including measurement configuration parameters, the RRC state corresponding to at least one of an RRC inactive state and an RRC idle state; identifying a service continuity trigger for one or more Multicast Broadcast Service (MBS) services based on measurement configuration parameters; Initiating a random access process (RAP) based on the identified service continuity trigger, where initiating the RAP includes transmitting a first message indicating a request for MBS configuration parameters associated with one or more MBS services; receiving one or more MBS configuration parameters in response to transmitting the first message; receiving data associated with one or more MBS services via the target cell while remaining in the RRC state based on MBS configuration parameters; Includes.

[0157] Clause 2. In the method of clause 1, the broadcast message is a system information block (SIB) message.

[0158] Clause 3. In the method of clause 1, the measurement configuration parameters include at least one of one or more thresholds, a carrier frequency for measurements, a frequency band list, beam-related measurement parameters, a measurement duration, a list of measurement cells, and a number of synchronization signal blocks (SSBs) for cell measurement derivation.

[0159] Clause 4. In the method of clause 1, the step of identifying a service continuity trigger includes measuring one or more synchronization signal blocks (SSBs) and comparing the received signal strength of the one or more SSBs to one or more thresholds.

[0160] Clause 5. The method of clause 1, wherein the first message includes a cause field indicating that the first message is sent in response to a service continuity trigger; and The first message is sent to request Multicast Broadcast Service (MBS) configuration parameters. The information includes at least one of the above.

[0161] Clause 6. In the method of clause 1, the radio resource control (RRC) corresponds to an inactive state, the first message is an RRC resume request message, and values ​​of one or more fields in the RRC resume request message indicate a request for one or more multicast broadcast service (MBS) configuration parameters while remaining in the RRC inactive state.

[0162] Clause 7. In the method of clause 6, the one or more fields include a restart cause field.

[0163] Clause 8. In the method of clause 6, receiving one or more Multicast Broadcast Service (MBS) configuration parameters includes receiving a Radio Resource Control (RRC) rejection message corresponding to an instruction to remain in an RRC inactive state.

[0164] Clause 9. In the method of clause 1, the one or more multicast broadcast service (MBS) configuration parameters include one or more first parameters for receiving control information.

[0165] Clause 10. In the method of clause 1, the one or more multicast broadcast service (MBS) configuration parameters include a bandwidth portion identifier, a control resource set, and a numerology associated with the one or more MBS services.

[0166] Clause 11. In the method of clause 1, the first message includes one or more service identifiers associated with one or more Multicast Broadcast Service (MBS) services provided by a current cell on which the user equipment (UE) is camped.

[0167] Clause 12. In the method of clause 11, the one or more multicast broadcast service (MBS) configuration parameters indicate one or more first service identifiers of the one or more MBS service identifiers, and the one or more first service identifiers are associated with the target cell.

[0168] 13. In the method of paragraph 1, one or more MBS services The Quality of Service (QoS) associated with a Multicast Broadcast Service (MBS) bearer associated with a service indicates the level of service continuity requirements for that MBS bearer.

[0169] Clause 14. The method of clause 1, wherein the random access process includes transmitting a random access preamble indicating that the random access process is associated with service continuity of a multicast broadcast service (MBS).

[0170] Clause 15. In the method of clause 1, the step of transmitting the first message includes transmitting the first message via a four-step random access process of message 3.

[0171] Clause 16. In the method of clause 15, the step of receiving one or more Multicast Broadcast Service (MBS) configuration parameters includes receiving the MBS configuration parameters via a four-step random access process of message 4.

[0172] Clause 17. In the method of clause 1, the step of transmitting the first message includes transmitting the first message via a two-step random access process of message A.

[0173] Clause 18: In the method of clause 17, receiving one or more Multicast Broadcast Service (MBS) configuration parameters includes receiving the MBS configuration parameters via message B in a two-step random access process.

[0174] Clause 19. The method of clause 1, further comprising receiving a radio resource control (RRC) release message indicating a transition to an RRC inactive state or an RRC idle state, wherein the RRC release message includes service continuity parameters for one or more multicast broadcast services (MBS).

[0175] Clause 20. In the method of clause 19, the radio resource control (RRC) release message includes a suspend config information element indicating a transition to an RRC inactive state and including service continuity parameters for one or more multicast broadcast services (MBS).

[0176] Clause 21. The method of clause 19, wherein the step of transmitting the first message is based on service continuity parameters of one or more multicast broadcast services (MBS).

[0177] Section 22. Equipment used in radio communication: an antenna used to transmit electromagnetic signals; a memory holding computer readable code; Executing the computer readable code causes the device to: causing a user equipment (UE) in a radio resource control (RRC) state to receive a broadcast message including measurement configuration parameters, the RRC state corresponding to at least one of an RRC inactive state and an RRC idle state; Identifying a service continuity trigger for one or more Multicast Broadcast Service (MBS) services based on measurement configuration parameters; Initiating a random access process (RAP) based on the identified service continuity trigger, initiating the RAP including transmitting a first message indicating a request for MBS configuration parameters associated with one or more MBS services; receiving one or more MBS configuration parameters in response to transmitting the first message; and receiving data associated with one or more MBS services via the target cell while remaining in the RRC state based on MBS configuration parameters. a processor; Includes.

[0178] Clause 23. In the apparatus of clause 22, the broadcast message is a system information block (SIB) message.

[0179] Clause 24. In the device of clause 22, the measurement configuration parameters include at least one of one or more thresholds, a carrier frequency for measurements, a frequency band list, beam-related measurement parameters, a measurement duration, a list of measurement cells, and a number of synchronization signal blocks (SSBs) for cell measurement derivation.

[0180] Clause 24. In the apparatus of clause 22, identifying a service continuity trigger includes measuring one or more synchronization signal blocks (SSBs) and comparing received signal strength of the one or more SSBs to one or more thresholds.

[0181] Clause 25. In the apparatus of clause 22, the first message includes information including an indication that the first message is sent in response to a service continuity trigger and / or that the first message is sent to request multicast broadcast service (MBS) configuration parameters.

[0182] Clause 26. In the apparatus of clause 22, a radio resource control (RRC) corresponds to an inactive state, the first message is an RRC resume request message, and values ​​of one or more fields in the RRC resume request message indicate a request for one or more multicast broadcast service (MBS) configuration parameters while remaining in the RRC inactive state.

[0183] Clause 27. In the apparatus of clause 26, the one or more fields include a restart cause field.

[0184] Clause 28. In the apparatus of clause 26, receiving one or more multicast broadcast service (MBS) configuration parameters includes receiving a radio resource control (RRC) rejection message corresponding to an instruction to remain in an RRC inactive state.

[0185] Clause 29: In the device of clause 22, the one or more multicast broadcast service (MBS) configuration parameters include one or more first parameters for receiving control information.

[0186] Clause 30. In the device of clause 22, the one or more multicast broadcast service (MBS) configuration parameters include a bandwidth portion identifier, a control resource set, and a numerology associated with the one or more MBS services.

[0187] Clause 31. In the apparatus of clause 22, the first message includes one or more service identifiers associated with one or more multicast broadcast service (MBS) services provided by a current cell on which the user equipment (UE) is camped.

[0188] Clause 32. In the device of clause 31, the one or more multicast broadcast service (MBS) configuration parameters indicate one or more first service identifiers of the one or more MBS service identifiers, the one or more first service identifiers being associated with the target cell.

[0189] Clause 33. In the apparatus of clause 22, the quality of service (QoS) associated with a multicast broadcast service (MBS) bearer associated with an MBS service among one or more MBS services indicates a level of service continuity requirement for that MBS bearer.

[0190] Clause 34. In the apparatus of clause 22, the random access process includes transmitting a random access preamble indicating that the random access process is associated with service continuity of a multicast broadcast service (MBS).

[0191] Clause 35. The device of clause 22, wherein the device transmits a first message according to a random access process.

[0192] 36. The apparatus of claim 22, wherein the apparatus is further configured to transmit a radio resource control (RRC) release message indicating a transition to an RRC inactive state or an RRC idle state, the RRC release message including one or more multicast broadcast service (MBS) service continuity parameters.

[0193] Clause 37. In the apparatus of clause 36, the radio resource control (RRC) release message includes a suspend config information element indicating a transition to an RRC inactive state and including service continuity parameters for one or more multicast broadcast services (MBS).

[0194] Section 38 The methods for maintaining service continuity are: transmitting a broadcast message including measurement configuration parameters to a user equipment (UE) in a radio resource control (RRC) state, the RRC state of the UE corresponding to at least one of an RRC inactive state and an RRC idle state; and receiving a first message from the UE indicating a request for MBS configuration parameters associated with one or more MBS services; sending one or more MBS configuration parameters to the UE in response to sending the first message; transmitting data associated with one or more MBS services via the target cell while remaining in the RRC state based on MBS configuration parameters; Includes.

[0195] Clause 39. In the method of clause 38, the broadcast message is a system information block (SIB) message.

[0196] Clause 40. In the method of clause 38, the measurement configuration parameters include at least one of one or more thresholds, a carrier frequency for measurements, a frequency band list, beam-related measurement parameters, a measurement duration, a list of measurement cells, and a number of synchronization signal blocks (SSBs) for cell measurement derivation.

[0197] Clause 41. The method of clause 38, wherein the first message includes a cause field that indicates that the first message is being sent in response to a service continuity trigger and that the first message is requesting Multicast Broadcast Service (MBS) configuration parameters. The information includes at least one indication that the information is being sent to

[0198] Clause 42: In the method of clause 38, the radio resource control (RRC) corresponds to an inactive state, the first message is an RRC resume request message, and values ​​of one or more fields in the RRC resume request message indicate a request for one or more multicast broadcast service (MBS) configuration parameters while remaining in the RRC inactive state.

[0199] Clause 43. In the method of clause 38, the step of transmitting one or more multicast broadcast service (MBS) configuration parameters includes transmitting a radio resource control (RRC) rejection message corresponding to an instruction to remain in an RRC inactive state.

[0200] Clause 44: In the method of clause 38, the one or more multicast broadcast service (MBS) configuration parameters include one or more first parameters for receiving control information.

[0201] Clause 45: In the method of clause 38, the one or more multicast broadcast service (MBS) configuration parameters include a bandwidth portion identifier, a control resource set, and a numerology associated with the one or more MBS services.

[0202] Clause 46. In the method of clause 38, the first message includes one or more service identifiers associated with one or more multicast broadcast service (MBS) services provided by a current cell on which the user equipment (UE) is camped.

[0203] Clause 47. In the method of clause 38, the one or more multicast broadcast service (MBS) configuration parameters indicate one or more first service identifiers of the one or more MBS service identifiers, the one or more first service identifiers being associated with the target cell.

[0204] Clause 48. In the method of clause 38, the quality of service (QoS) associated with a multicast broadcast service (MBS) bearer associated with an MBS service of the one or more MBS services indicates a level of service continuity requirement for that MBS bearer.

[0205] Clause 49: In the method of clause 38, the random access process includes transmitting a random access preamble indicating that the random access process is associated with service continuity of a multicast broadcast service (MBS).

[0206] Clause 50: In the method of clause 38, the step of transmitting the first message is performed according to a random access process.

[0207] Clause 51: The method of clause 38, further comprising transmitting a radio resource control (RRC) release message indicating a transition to an RRC inactive state or an RRC idle state, wherein the RRC release message includes service continuity parameters for one or more multicast broadcast services (MBS).

[0208] 52. The method of claim 51, wherein the radio resource control (RRC) release message indicates a transition to an RRC inactive state and includes one or more multicast broadcasts. The suspend config information element contains the service continuity parameters for Multi-Band Service (MBS).

[0209] Section 53. Equipment used in radio communication: an antenna used to transmit electromagnetic signals; a memory holding computer readable code; Executing the computer readable code causes the device to: receiving, by a user equipment (UE) in a radio resource control (RRC) state, a broadcast message including measurement configuration parameters, the RRC state of the UE corresponding to at least one of an RRC inactive state and an RRC idle state; receiving, from the UE, a first message indicating a request for MBS configuration parameters associated with one or more MBS services; causing the UE to transmit one or more MBS configuration parameters in response to transmitting the first message; transmit data associated with one or more MBS services through the target cell while remaining in that RRC state based on MBS configuration parameters; a processor; Includes.

[0210] Clause 54. In the apparatus of clause 53, the broadcast message is a system information block (SIB) message.

[0211] Clause 55. In the device of clause 53, the measurement configuration parameters include at least one of one or more thresholds, a carrier frequency for measurements, a frequency band list, beam-related measurement parameters, a measurement duration, a list of measurement cells, and a number of synchronization signal blocks (SSBs) for cell measurement derivation.

[0212] Clause 56. In the apparatus of clause 53, the first message includes a cause field having information including an indication that the first message is being sent in response to a service continuity trigger and / or that the first message is being sent to request multicast broadcast service (MBS) configuration parameters.

[0213] 57. The apparatus of claim 53, wherein the radio resource control (RRC) supports an inactive state; The first message is an RRC Resume Request message, The values ​​of one or more fields in the RRC Resume Request message indicate a request for one or more Multicast Broadcast Service (MBS) configuration parameters while remaining in the RRC inactive state.

[0214] Clause 58. The device of clause 42, wherein the device is further configured to transmit a radio resource control (RRC) rejection message corresponding to the command to remain in the RRC inactive state.

[0215] Clause 59: In the apparatus of clause 53, the one or more multicast broadcast service (MBS) configuration parameters include one or more first parameters for receiving control information.

[0216] Clause 60. In the apparatus of clause 53, the one or more multicast broadcast service (MBS) configuration parameters include a bandwidth portion identifier, a control resource set, and a numerology associated with the one or more MBS services.

[0217] Clause 61. In the apparatus of clause 53, the first message includes one or more service identifiers associated with one or more multicast broadcast service (MBS) services provided by a current cell on which the user equipment (UE) is camped.

[0218] Clause 62. In the device of clause 53, the one or more multicast broadcast service (MBS) configuration parameters indicate one or more first service identifiers of the one or more MBS service identifiers, the one or more first service identifiers being associated with the target cell.

[0219] Clause 63. In the apparatus of clause 53, the quality of service (QoS) associated with a multicast broadcast service (MBS) bearer associated with an MBS service of one or more MBS services indicates a level of service continuity requirement for that MBS bearer.

[0220] Clause 64: In the apparatus of clause 53, the random access process includes transmitting a random access preamble indicating that the random access process is associated with service continuity of a multicast broadcast service (MBS).

[0221] Clause 65. The device of clause 53, wherein the device is further configured to transmit the first message according to a random access process.

[0222] Clause 66: In the device of clause 53, the device is further configured to transmit a radio resource control (RRC) release message indicating a transition to an RRC inactive state or an RRC idle state, the RRC release message including one or more multicast broadcast service (MBS) service continuity parameters.

[0223] Clause 67. In the apparatus of clause 51, the radio resource control (RRC) release message includes a suspend config information element indicating a transition to an RRC inactive state and including service continuity parameters for one or more multicast broadcast services (MBS).

[0224] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 076,704, filed September 10, 2020, entitled "SYSTEM AND METHOD FOR MAINTAINING MULTICAST BROADCAST SERVICE CONTINUITY IN IDLE AND INACTIVE STATES," which is incorporated herein by reference.

Claims

1. 1. A method for maintaining continuity of one or more Multicast Broadcast Service (MBS) services during cell reselection in a user equipment (UE) receiving one or more MBS services in at least one of a Radio Resource Control (RRC) inactive state and an RRC idle state, comprising: receiving system information including first information used for measuring neighboring cells in the RRC inactive state or the RRC idle state; performing measurements on the neighboring cells based on the first information and performing cell reselection; receiving second information indicating whether the MBS service is provided in the neighboring cell; obtaining third information indicating a frequency at which the MBS service is provided in the neighboring cell, the third information being different from the second information; receiving data associated with the MBS service via the target cell reselected based on the third information while remaining in the RRC inactive state or the RRC idle state; A method comprising:

2. A level of mobility for the MBS service in the RRC inactive state or the RRC idle state is configurable per MBS service and / or per UE. The method of claim 1.

3. the system information is a system information block (SIB) message; The method of claim 1.

4. the first information includes at least one of one or more thresholds, a carrier frequency for measurements, a frequency band list, beam-related measurement parameters, a measurement duration, a list of measurement cells, and a number of synchronization signal blocks (SSBs) for cell measurement derivation; The method of claim 1.

5. measuring the neighboring cells includes measuring one or more synchronization signal blocks (SSBs) and comparing received signal strengths of the one or more SSBs to one or more thresholds; The method of claim 1.

6. The third information includes a bandwidth portion identifier, a control resource set, and a numerology associated with the MBS service. The method of claim 1.

7. a Quality of Service (QoS) associated with a Multicast Broadcast Service (MBS) bearer associated with an MBS service of the one or more MBS services indicates a level of service continuity requirement for the MBS bearer; The method of claim 1.

8. 1. A processing method of a network device connected to a user equipment (UE) receiving one or more multicast broadcast service (MBS) services in at least one of a radio resource control (RRC) inactive state and an RRC idle state, for maintaining continuity of the MBS service during cell reselection in the UE, the method comprising: transmitting system information including first information used by the UE in the RRC inactive state or the RRC idle state to measure neighboring cells; transmitting second information indicating whether the MBS service is provided in the neighboring cell; transmitting third information indicating a frequency at which the MBS service is provided in the neighboring cell, the third information being different from the second information; transmitting data associated with an MBS service via the target cell reselected by the UE in the RRC inactive state or the RRC idle state based on the third information; A method comprising:

9. A mobility level for the MBS service in the RRC inactive state or the RRC idle state is configurable for each MBS service and / or for each UE. The method of claim 8.

10. the first information is included in a system information block (SIB) message; The method of claim 8.

11. the first information includes at least one of one or more thresholds, a carrier frequency for measurements, a frequency band list, beam-related measurement parameters, a measurement duration, a list of measurement cells, and a number of synchronization signal blocks (SSBs) for cell measurement derivation; The method of claim 8.

12. The third information includes a bandwidth portion identifier, a control resource set, and a numerology associated with the MBS service. The method of claim 8.

13. a Quality of Service (QoS) associated with a Multicast Broadcast Service (MBS) bearer associated with an MBS service of the one or more MBS services indicates a level of service continuity requirement for the MBS bearer; The method of claim 8.

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