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

Abstract

Systems, methods, and apparatuses for mobile communications are provided. A broadcast message including measurement configuration parameters is received by a user equipment (UE) in a radio resource control state. The UE determines a service continuity trigger for one or more multicast broadcast service (MBS) services based on the measurement configuration parameters. In response to the determined service continuity trigger, a random access procedure (RAP) is initiated, where initiating the RAP includes transmitting a first message indicating a request for MBS configuration parameters associated with the one or more MBS services. The UE receives the one or more MBS configuration parameters in response to transmitting the first message. The UE then receives data associated with the one or more MBS services via a target cell based on the MBS configuration parameters while remaining in the RRC state.

Description

Technical Field

[0001] This disclosure relates to methods for maintaining service continuity. Background Technology

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

[0003] Wireless communication networks can include a variety of devices that include or connect to components for accessing the wireless communication network. Such devices can utilize the wireless communication network to facilitate interaction with other devices capable of accessing the wireless communication network, or to facilitate interaction with devices utilizing other communication networks. Summary of the Invention

[0004] One embodiment of the present invention is a method for maintaining service continuity. The method includes: receiving a broadcast message including measured configuration parameters by a user equipment (UE) in a Radio Resource Control (RRC) state, wherein the RRC state corresponds to at least one of an RRC inactive state and an RRC idle state; determining a service continuity trigger for one or more Multicast Broadcast Service (MBS) services based on the measured configuration parameters; initiating a Random Access Process (RAP) based on the determined service continuity trigger, wherein initiating the RAP includes transmitting a first message indicating a request for MBS configuration parameters associated with the one or more MBS services; receiving the one or more MBS configuration parameters in response to transmitting the first message; and receiving data associated with the one or more MBS services via a target cell based on the MBS configuration parameters while remaining in the RRC state. Attached Figure Description

[0005] [ Figure 1 ] Figure 1 Examples of mobile communication systems are shown, illustrating some aspects of a mobile communication system according to one or more exemplary embodiments of this disclosure. [Figure 2] Figure 2A and Figure 2B Examples of radio protocol stacks for the user plane and control plane, respectively, are shown according to one or more exemplary embodiments of this disclosure. [Figure 3] Figure 3A , Figure 3B and Figure 3CExemplary mappings between logical channels and transport channels in downlink, uplink, and sidelink according to one or more exemplary embodiments of this disclosure are shown respectively. [Figure 4] Figure 4A , Figure 4B and Figure 4C Exemplary mappings between transport channels and physical channels in downlink, uplink, and sidelink according to one or more exemplary embodiments of this disclosure are shown respectively. [Figure 5] Figure 5A , Figure 5B , Figure 5C and Figure 5D Examples of radio protocol stacks for NR-side link communication are shown, representing some aspects of one or more exemplary embodiments of this disclosure. [ Figure 6 ] Figure 6 Example physical signals in the downlink, uplink, and sidelink of some aspects according to one or more exemplary embodiments of this disclosure are shown. [ Figure 7 ] Figure 7 Examples of Radio Resource Control (RRC) states and transitions between different RRC states are shown, representing some aspects of one or more exemplary embodiments of this disclosure. [ Figure 8 ] Figure 8 Example frame structures and physical resources are shown, representing some aspects of one or more exemplary embodiments according to this disclosure. [ Figure 9 ] Figure 9 Exemplary member carrier configurations in different carrier aggregation scenarios are shown in accordance with one or more exemplary embodiments of this disclosure. [ Figure 10 ] Figure 10 Example portions of bandwidth configuration and switching are shown, representing some aspects of one or more exemplary embodiments according to this disclosure. [ Figure 11 ] Figure 11 Example four-step contention-based random access procedures and contention-free random access procedures are shown, illustrating some aspects of one or more exemplary embodiments of this disclosure. [ Figure 12 ] Figure 12 Examples of two-step contention-based random access procedures and contention-free random access procedures are shown, illustrating some aspects of one or more exemplary embodiments of the present disclosure. [ Figure 13 ] Figure 13Example time and frequency structures of a Synchronization Signal and PBCH Block (SSB) are shown, representing some aspects of one or more exemplary embodiments of the present disclosure. [ Figure 14 ] Figure 14 Example SSB burst transmissions are shown, illustrating some aspects of one or more exemplary embodiments according to this disclosure. [ Figure 15 ] Figure 15 Example components of user equipment and base stations for transmission and / or reception are shown, representing some aspects of one or more exemplary embodiments of this disclosure. [ Figure 16A ] Figure 16A An example RRC recovery process is shown, illustrating some aspects of one or more exemplary embodiments according to this disclosure. [ Figure 16B ] Figure 16B An example RRC recovery process is shown, illustrating some aspects of one or more exemplary embodiments according to this disclosure. [ Figure 16C ] Figure 16C An example RRC recovery process is shown, illustrating some aspects of one or more exemplary embodiments according to this disclosure. [ Figure 16D ] Figure 16D An example RRC recovery process is shown, illustrating some aspects of one or more exemplary embodiments according to this disclosure. [ Figure 16E ] Figure 16E An example RRC recovery process is shown, illustrating some aspects of one or more exemplary embodiments according to this disclosure. [ Figure 17 ] Figure 17 An example procedure is shown for service continuity during RRC inactivity and / or RRC idle states. [ Figure 18 ] Figure 18 An example procedure is shown for service continuity during RRC inactivity and / or RRC idle states. [ Figure 19 ] Figure 19 An example procedure is shown for service continuity during RRC inactivity and / or RRC idle states. Detailed Implementation

[0006] Figure 1Examples of mobile communication systems 100 according to one or more exemplary embodiments of the present disclosure are shown. 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 (DMO), a Multiple System Operator (MSO), or an Internet of Things (IoT) network operator, and may provide services such as voice, data (e.g., wireless Internet access), messaging, vehicle communication services such as Vehicle to Everything (V2X) communication services, security services, mission-critical services, and services in residential, commercial, or industrial environments such as IoT and Industrial IoT (IIOT).

[0007] Mobile communication system 100 can support various types of applications with different requirements in terms of latency, reliability, and throughput. Examples of supported applications include enhanced mobile broadband (eMBB), ultra-reliable low-latency communication (URLLC), and massive machine-type communication (mMTC). eMBB can support stable connections with high peak data rates as well as medium rates for cell-edge users. URLLC can support applications with stringent requirements for latency and reliability and medium requirements for data rates. Example mMTC applications include networks of numerous IoT devices that are only occasionally active and send small data payloads.

[0008] The mobile communication system 100 may include a radio access network (RAN) portion and a core network portion. Figure 1The examples shown illustrate a Next-Generation RAN (NG-RAN) 105 and a 5G Core Network (5g-CN) 110 as examples of RAN and core network, respectively. Other examples of RAN and core network can be implemented without departing from the scope of this disclosure. Other examples of RAN include Evolved Universal Terrestrial Radio Access Network (EUTRAN), Universal Terrestrial Radio Access Network (UTRAN), etc. Other examples of core network include Evolved Packet Core (EPC), UMTS Core Network (UCN), etc. The RAN implements Radio Access Technology (RAT) and resides between User Equipment (UE) 125 and the core network. Examples of such RATs include New Radio (NR), Long Term Evolution (LTE) (also known as Evolved Universal Terrestrial Radio Access (EUTRA)), and Universal Mobile Telecommunication System (UMTS). The RAT of the example mobile communication system 100 could be NR. The core network resides between the RAN and one or more external networks (e.g., data networks) and is responsible for functions such as mobility management, authentication, session management, establishing bearers and applications with different Quality of Service (QoS) levels. The functional layer between UE 125 and the RAN (e.g., NG-RAN 105) can be referred to as the Access Stratum (AS), and the functional layer between UE 125 and the core network (e.g., 5G-CN 110) can be referred to as the Non-access Stratum (NAS).

[0009] UE 125 may include wireless transmitting and receiving devices for communicating with one or more nodes, one or more relay nodes, or one or more other UEs in the RAN. Examples of UEs include, but are not limited to, smartphones, tablets, laptops, computers, wireless transmitting and / or receiving units in vehicles, V2X or vehicle-to-vehicle (V2V) devices, wireless sensors, IoT devices, IIoT devices, etc. Other names may be used for UEs, such as Mobile Station (MS), Terminal Equipment, Terminal Node, Client Equipment, Mobile Equipment, etc. Furthermore, UE 125 may also include components or sub-components integrated into other devices such as vehicles to provide wireless communication capabilities with nodes in the RAN as described herein. In addition to wireless communication, such other devices may also have other or multiple functions.

[0010] The RAN may include nodes (e.g., base stations) for communicating with the UE. For example, the NG-RAN 105 of mobile communication system 100 may include nodes for communicating with the UE 125. Depending on the RAT used by the RAN, different names may be used for the RAN nodes. In a RAN using the UMTS RAT, the RAN node may be referred to as Node B (NB). In a RAN using the LTE / EUTRA RAT, the RAN node may be referred to as an evolved Node B (eNB). Figure 1 In an illustrative example of the mobile communication system 100, the nodes of NG-RAN 105 may be next-generation node B (gNB) 115 or next-generation evolved node B (ng-eNB) 120. In this specification, the terms base station, RAN node, gNB, and ng-eNB are used interchangeably. Illustratively, a communication network may be characterized as a collection of geographical areas (called cells), which may be logically organized in a manner that is appropriate. Cells are organized in such a way that a single cell can be associated with one or more base stations that establish wireless communication with multiple UEs. Base stations may be physically located within a single cell, such that radio signals transmitted from the cell can be received by UEs that are also physically within the cell. In other embodiments, base stations that may be located outside the physical cell may be configured to transmit radio signals to UEs within the cell. In some embodiments, due to overlapping signal coverage, individual UEs may be able to receive signals transmitted between adjacent cells. Therefore, references to communication from a target cell or an existing cell may refer to a connection between one or more base stations belonging to that cell and UE 125.

[0011] The gNB 115 can provide NR user plane and control plane protocol terminals to the UE 125. The NG-eNB 120 can provide E-UTRA user plane and control plane protocol terminals to the UE 125. The interface between the gNB 115 and the UE 125, or between the ng-eNB 120 and the UE 125, can be referred to as the Uu interface. The Uu interface can be established together with the user plane protocol stack and the control plane protocol stack. For the Uu interface, the direction from the base station (e.g., gNB 115 or ng-eNB 120) to the UE 125 can be referred to as the downlink, and the direction from the UE 125 to the base station (e.g., gNB 115 or ng-eNB 120) can be referred to as the uplink.

[0012] gNB 115 and ng-eNB 120 can interconnect via the Xn interface. The Xn interface can include an Xn user plane (Xn-U) interface and an Xn control plane (Xn-C) interface. The Xn-U interface's transport network layer can be built on Internet Protocol (IP) transport and can use the GPRS Tunneling Protocol (GTP) over User Datagram Protocol (UDP) / IP to carry User Plane Protocol Data Units (PDUs). Xn-U can provide non-guaranteed delivery of User Plane PDUs and can support data forwarding and flow control. The Xn-C interface's transport network layer can be built on the Stream Control Transport Protocol (SCTP) over IP. The application layer signaling protocol can be referred to as XnAP (Xn Application Protocol). The SCTP layer can provide guaranteed delivery of application layer messages. In the transport IP layer, point-to-point transmission can be used to deliver signaling PDUs. The Xn-C interface can support Xn interface management, UE mobility management including context transmission and RAN paging, and dual connectivity.

[0013] The gNB 115 and ng-eNB 120 can also connect to the 5GC 110 via the NG interface. More specifically, they connect to the Access and Mobility Management Function (AMF) 130 of the 5GC 110 via the NG-C interface, and to the User Plane Function (UPF) 135 of the 5GC 110 via the NG-U interface. The transport network layer of the NG-U interface can be built on top of IP transport, and the GTP protocol can be used over UDP / IP to carry user plane PDUs between the NG-RAN node (e.g., gNB 115 or ng-eNB 120) and the UPF 135. NG-U can provide non-guaranteed delivery of user plane PDUs between the NG-RAN node and the UPF. The transport network layer of the NG-C interface can be built on top of IP transport. For reliable transmission of signaling messages, SCTP can be added on top of IP. The application layer signaling protocol can be called NGAP (NG Application Protocol). The SCTP layer can provide guaranteed delivery of application layer messages. During transmission, IP layer point-to-point transmission can be used to deliver signaling PDUs. The NG-C interface can provide the following functions: NG interface management; UE context management; UE mobility management; NAS message transmission; paging; PDU session management; configuration transmission; and warning message transmission.

[0014] The gNB 115 or ng-eNB 120 can host one or more of the following functions: radio resource management functions, such as radio bearer control, radio admission control, connection mobility control, dynamic allocation of resources to the UE in the uplink and downlink (e.g., scheduling); IP and Ethernet header compression, encryption, and integrity protection of data; selection of the AMF at the UE's attachment device when it can be determined from information provided by the UE that there is no route to the AMF; routing user plane data to one or more UPFs; routing control plane information to the AMF; connection establishment and release; scheduling and transmission of paging messages; scheduling and transmission of system broadcast information (e.g., originating from the AMF); mobility and scheduling measurement and measurement report configuration; transport layer packet marking in the uplink; session management; network slicing support; QoS flow management and mapping to data radio bearers; support for UEs in RRC inactive state; NAS message distribution function; radio access network sharing; dual connectivity; tight interoperability between NR and E-UTRA; and maintaining the 5G system for user plane (5G System, 5GS) Cellular IoT (CIoT) optimized security and radio configuration.

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

[0016] UPF 135 can host one or more of the following functions: anchor points for intra / inter-RAT mobility (where applicable); external PDU session points for interconnection with data networks; packet routing and forwarding; user plane portion of packet inspection and policy rule enforcement; traffic usage reporting; uplink classifiers to support routing traffic flows to data networks; branch points to support multihomed PDU sessions; QoS processing for user plane, such as packet filtering, gating, UL / DL rate enforcement; uplink traffic authentication (Service Data Flow (SDF) to QoS flow mapping); downlink packet buffering and downlink data notification triggering.

[0017] like Figure 1 As shown, NG-RAN 105 can support a PC5 interface between two UEs 125 (e.g., UE 125A and UE 125B). In the PC5 interface, the communication direction between the two UEs (e.g., from UE 125A to UE 125B or vice versa) can be referred to as a sidelink. Sidelink transmission and reception via the PC5 interface can be supported when UE 125 is within the NG-RAN 105 coverage area, regardless of its RRC state, and also when UE 125 is outside the NG-RAN 105 coverage area. Support for V2X services via the PC5 interface can be provided by NR sidelink communication and / or V2X sidelink communication.

[0018] PC5-S signaling can be used for unicast link establishment with direct communication request / accept messages. The UE can, for example, self-assign its source stratum 2 ID for the PC5 unicast link based on the V2X service type. During the unicast link establishment process, the UE can send its source stratum 2 ID for the PC5 unicast link to a peer UE (e.g., a UE that has already received the destination ID from the upper layer). A pair of source stratum 2 IDs and destination stratum 2 IDs can uniquely identify the unicast link. The receiving UE can verify that the destination ID belongs to it and can accept the unicast link establishment request from the source UE. During the PC5 unicast link establishment process, the PC5-RRC procedure on the access layer can be invoked for UE-sidelink context establishment and AS layer configuration, capability exchange, etc. PC5-RRC signaling enables the exchange of UE capabilities and AS layer configurations, such as sidelink radio bearer configuration, between a pair of UEs that have established a PC5 unicast link.

[0019] NR sidelink communication can support one of three transmission modes (e.g., unicast, multicast, and broadcast) for a pair of source layer 2IDs and destination layer 2IDs in the AS. Unicast transmission mode is characterized by: support for a PC5-RRC connection between the peer UEs in the pair; transmission and reception of control information and user traffic between peer UEs in the sidelink; support for sidelink HARQ feedback; support for sidelink transmission power control; support for RLC Acknowledged Mode (AM); and detection of radio link failures in the PC5-RRC connection. Multicast transmission is characterized by: transmission and reception of user traffic between a group of UEs in the sidelink; and support for sidelink HARQ feedback. Broadcast transmission is characterized by: transmission and reception of user traffic between UEs in the sidelink.

[0020] Source Layer 2 ID, Destination Layer 2 ID, and PC5 Link Identifier can be used in NR-side walkway communication. The Source Layer 2 ID identifies the sender of data in NR-side walkway communication. The Source Layer 2 ID can be 24 bits long and can be split into two bit strings at the MAC layer: one bit string can be the LSB portion (8 bits) of the Source Layer 2 ID and is forwarded to the sender's physical layer. This can identify the source of the expected data in the walkway control information and can be used to filter packets at the receiver's physical layer. The second bit string can be the MSB portion (16 bits) of the Source Layer 2 ID and can be carried in the Medium Access Control (MAC) header. This can be used to filter packets at the receiver's MAC layer. The Destination Layer 2 ID identifies the destination of data in NR-side walkway communication. For NR-side walkway communication, the Destination Layer 2 ID can be 24 bits long and can be split into two bit strings at the MAC layer: one bit string can be the LSB portion (16 bits) of the Destination Layer 2 ID and is forwarded to the sender's physical layer. This can identify the target of the intended data in the sidelink control information and can be used to filter packets at the physical layer of the receiver. The second bit string can be the MSB portion (8 bits) of the destination layer 2ID and can be carried in the MAC header. This can be used to filter packets at the MAC layer of the receiver. The PC5 link identifier can uniquely identify the PC5 unicast link in the UE during the lifetime of the PC5 unicast link. The PC5 link identifier can be used to indicate a PC5 unicast link that has made a sidelink radio link failure (RLF) declaration and whose PC5-RRC connection has been released.

[0021] Figure 2A and Figure 2B Examples of radio protocol stacks for the user plane and control plane, respectively, are shown, representing some aspects of one or more exemplary embodiments according to this disclosure. Figure 2A As shown, the protocol stack for the user plane of the Uu interface (between UE 125 and gNB115) 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 sublayers, and Physical (PHY) 205 and PHY 215 layers (Layer 1 is also referred to as L1).

[0022] 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 streams 240 to 5GC.

[0023] The main services and functions of the MAC 204 or MAC 214 sublayer include: mapping between logical channels and transport channels; multiplexing MAC Service Data Units (SDUs) belonging to one or different logical channels into / demultiplexing them from transport blocks (TBs) passed to the physical layer on the transport channel; scheduling of information reports; error correction via Hybrid Automatic Repeat Request (HARQ) (one HARQ entity per cell in the case of Carrier Aggregation (CA)); priority handling among UEs using dynamic scheduling; priority handling among logical channels of a UE via Logical Channel Prioritization (LCP); priority handling among overlapping resources of a UE; and padding. A single MAC entity can support multiple parameter sets (numerology), transmission timings, and cells. Mapping constraints in logical channel priorities control which parameter set(s), cells(s), and transmission timings(s) a logical channel can use.

[0024] The HARQ function ensures delivery between peer entities at Layer 1. When the physical layer is not configured for downlink / uplink spatial multiplexing, a single HARQ process can support one TB, and when the physical layer is configured for downlink / uplink spatial multiplexing, a single HARQ process can support one or more TBs.

[0025] The RLC 203 or RLC 213 sublayer can support three transmission modes: Transparent Mode (TM); Unacknowledged Mode (UM); and Acknowledged Mode (AM). RLC configuration can be applied to each logical channel, regardless of the parameter set and / or transmission duration, and Automatic Repeat Request (ARQ) can operate on any parameter set and / or transmission duration configured for the logical channel.

[0026] The primary services and functions of the RLC 203 or RLC 213 sublayer depend on the transport mode (e.g., TM, UM, or AM) and may include: transmission of upper-layer PDUs; sequence numbering independent of sequence numbering in PDCP (UM and AM); error correction via ARQ (AM only); segmentation (AM and UM) and resegmentation (AM only) of RLC SDUs; reassembly of SDUs (AM and UM); duplicate detection (AM only); RLC SDU discarding (AM and UM); RLC reconstruction; and protocol error detection (AM only).

[0027] Automatic repeat requests within the RLC 203 or RLC 213 sublayer may have the following features: ARQ retransmits RLC SDUs or RLC SDU segments based on RLC status reports; polling of RLC status reports can be used when needed by the RLC; and the RLC receiver can also trigger an RLC status report after detecting a lost RLC SDU or RLC SDU segment.

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

[0029] The main services and functions of SDAP 201 or SDAP 211 include: mapping between QoS flows and data radio bearers; and marking QoS flow IDs (QFIs) in downlink and uplink packets. A single protocol entity for SDAP can be configured for each individual PDU session.

[0030] like Figure 2BAs shown, the protocol stack of the control plane of the Uu interface (between UE 125 and gNB 115) includes the PHY layer (layer 1), and the MAC, RLC and PDCP sublayers of layer 2 as described above, as well as the RRC 206 sublayer and RRC 216 sublayer. The main services and functions of the RRC 206 and RRC 216 sublayers on the Uu interface include: broadcasting system information related to AS and NAS; paging initiated by 5GC or NG-RAN; establishment, maintenance, and release of RRC connections between UE and NG-RAN (including the addition, modification, and release of carrier aggregation; and the addition, modification, and release of dual connections in NR or between E-UTRA and NR); security functions including key management; establishment, configuration, maintenance, and release of SRB and DRB; mobility functions (including handover and context transfer; UE cell selection and reselection and control of cell selection and reselection; and inter-RAT mobility); QoS management functions; UE measurement reporting and control of such reporting; detection and recovery from radio link failures; and NAS message transmission from UE to NAS and from NAS to UE. NAS 207 and NAS 227 layers are control protocols that perform functions such as authentication, mobility management, and security control (terminating at the network-side AMF).

[0031] The specific services and functions of the sidelink in 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; and reporting of UE auxiliary information for (one or more) SL service modes.

[0032] Figure 3A , Figure 3B and Figure 3CExample mappings between logical channels and transport channels in the downlink, uplink, and sidelink according to one or more exemplary embodiments of this disclosure are shown respectively. Different types of data transmission services can be provided by MAC. Each logical channel type can be defined by what type of information is transmitted. Logical channels can be classified into two groups: control channels and traffic channels. Control channels can be used only for the transmission of control plane information. The Broadcast Control Channel (BCCH) is a downlink channel used for broadcasting system control information. The Paging Control Channel (PCCH) is a downlink channel carrying paging messages. The Common Control Channel (CCCH) is a channel used for transmitting control information between the UE and the network. This channel can be used by UEs without a network RRC connection. The Dedicated Control Channel (DCCH) is a point-to-point bidirectional channel for transmitting dedicated control information between the UE and the network and can be used by UEs with an RRC connection. Traffic channels can be used only for the transmission of user plane information. A Dedicated Traffic Channel (DTCH) is a point-to-point channel dedicated to a single UE for transmitting user information. DTCHs can exist in both the uplink and downlink. A Sidelink Control Channel (SCCH) is a sidelink channel used to transmit control information (e.g., PC5-RRC and PC5-S messages) from one UE to another (or more) UEs. A Sidelink Traffic Channel (STCH) is a sidelink channel used to transmit user information from one UE to another (or more) UEs. A Sidelink Broadcast Control Channel (SBCCH) is a sidelink channel used to broadcast sidelink system information from one UE to another (or more) UEs.

[0033] Downlink transport channel types include Broadcast Channel (BCH), Downlink Shared Channel (DL-SCH), and Paging Channel (PCH). BCH is characterized by: a fixed, predefined transmission format; and the requirement to broadcast as a single message or through beamforming of different BCH instances throughout the cell's coverage area. DL-SCH is characterized by: support for HARQ; support for dynamic link adaptation by changing modulation, coding, and transmission power; the possibility of broadcasting throughout the cell; the possibility of using beamforming; support for dynamic and semi-static resource allocation; and support for Discontinuous Reception (DRX) to achieve UE power savings. The features of a PCH may include: supporting discontinuous reception (DRX) for UE power saving (DRX period is indicated to the UE by the network); broadcasting as a single message or through beamforming different BCH instances throughout the cell's coverage area; and mapping to physical resources that can also be dynamically used for traffic / other control channels.

[0034] In the downlink, the following connections can exist between logical channels and transport channels: BCCH can be mapped to BCH; BCCH can be mapped to DL-SCH; PCCH can be mapped to PCH; CCCH can be mapped to DL-SCH; DCCH can be mapped to DL-SCH; and DTCH can be mapped to DL-SCH.

[0035] Uplink transport channel types include Uplink Shared Channel (UL-SCH) and (one or more) Random Access Channels (RACH). UL-SCH is characterized by: the possibility of beamforming; support for dynamic link adaptation through variations in transmission power and possible modulation and coding; support for HARQ; and support for dynamic and semi-static resource allocation. RACH can be characterized by limited control information and collision risk.

[0036] In the uplink, the following connections can exist between logical channels and transport channels: CCCH can be mapped to UL-SCH; DCCH can be mapped to UL-SCH; and DTCH can be mapped to UL-SCH.

[0037] Sidelink transmission channel types include: Sidelink broadcast channel (SL-BCH) and Sidelink shared channel (SL-SCH). SL-BCH can be characterized by a predefined transmission format. SL-SCH features include: support for unicast, multicast, and broadcast transmission; support for UE-autonomous resource selection and scheduling by NG-RAN; support for dynamic and semi-static resource allocation when NG-RAN allocates resources to the UE; support for HARQ; and support for dynamic link adaptation by changing transmission power, modulation, and coding.

[0038] In a side link, the following connections can exist between logical channels and transport channels: SCCH can be mapped to SL-SCH; STCH can be mapped to SL-SCH; and SBCCH can be mapped to SL-BCH.

[0039] Figure 4A , Figure 4B and Figure 4C Example mappings between transport channels and physical channels in the downlink, uplink, and sidelink according to one or more exemplary embodiments of this disclosure are shown respectively. The physical channels in the downlink include the Physical Downlink Shared Channel (PDSCH), the Physical Downlink Control Channel (PDCCH), and the 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. The transport channels are not mapped to the PDCCH but instead transmit downlink control information (DCI) via the PDCCH.

[0040] The physical channels in the uplink include the Physical Uplink Shared Channel (PUSCH), the Physical Uplink Control Channel (PUCCH), and the Physical Random Access Channel (PRACH). The UL-SCH transport channel 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; instead, uplink control information (UCI) is transmitted via the PUCCH.

[0041] The physical channels in the sidelink include the Physical Sidelink Shared Channel (PSSCH), the Physical Sidelink Control Channel (PSCCH), the Physical Sidelink Feedback Channel (PSFCH), and the Physical Sidelink Broadcast Channel (PSBCH). The PSCCH indicates the resources and other transmission parameters used by the UE for the PSSCH. The PSSCH transmits the data's TB (Bill of Materials), as well as control information for the HARQ process and CSI feedback triggers. At least six OFDM symbols within a time slot can be used for PSSCH transmission. The PSFCH carries HARQ feedback on the sidelink from the UE intended to receive the PSSCH transmission to the UE performing the transmission. The PSFCH sequence can be transmitted in a PRB (Physical Sidelink Relay) repeated on two OFDM symbols near the end of the sidelink resources within a time slot. The SL-SCH transport channel can be mapped to the PSSCH. The SL-BCH can be mapped to the PSBCH. No transport channels are mapped to the PSFCH, but Sidelink Feedback Control Information (SFCI) can be mapped to the PSFCH. No transport channels are mapped to the PSCCH, but Sidelink Control Information (SCI) can be mapped to the PSCCH.

[0042] Figure 5A , Figure 5B , Figure 5C and Figure 5D Examples of radio protocol stacks for NR-side link communication are shown, illustrating some aspects of one or more exemplary embodiments of this disclosure. The AS protocol stack for the user plane (i.e., for STCH) in the PC5 interface may consist of SDAP, PDCP, RLC, and MAC sublayers, as well as a physical layer. The user plane protocol stack in... Figure 5A As shown in the diagram, the SBCCH AS protocol stack in the PC5 interface can consist of RRC, RLC, MAC sublayer, and physical layer, as follows: Figure 5B As shown in the diagram. To support the PC5-S protocol, PC5-S sits above the PDCP, RLC, and MAC sublayers and the physical layer in the control plane protocol stack of the SCCH used for PC5-S, as shown in the diagram. Figure 5C As shown in the diagram, the AS protocol stack of the control plane for the SCCH of RRC in the PC5 interface consists of RRC, PDCP, RLC, and MAC sublayers, as well as the physical layer. The protocol stack of the control plane for the SCCH of RRC is shown in... Figure 5D As shown in the image.

[0043] Sidelink radio bearers (SLRBs) can be classified into two groups: sidelink data radio bearers (SL DRBs) for user plane data and sidelink signaling radio bearers (SL SRBs) for control plane data. Separate SL SRBs with different SCCHs can be configured for PC5-RRC and PC5-S signaling respectively.

[0044] The MAC sublayer can provide the following services and functions through the PC5 interface: radio resource selection; packet filtering; prioritization of processing between uplink and sidelink transmissions for a given UE; and sidelink CSI reporting. With logical channel prioritization constraints in the MAC, for each unicast, multicast, and broadcast transmission that may be associated with a destination, only sidelink logical channels belonging to the same destination can be multiplexed as a MAC PDU. For packet filtering, an SL-SCH MAC header including portions of the source 2ID and destination 2ID can be added to the MAC PDU. The Logical Channel Identifier (LCID) included in the MAC subheader can uniquely identify logical channels within the range of the source 2ID and destination 2ID combination.

[0045] Services and functions of the RLC sublayer can be supported for sidelinks. RLC unacknowledged mode (UM) and acknowledged mode (AM) can be used in unicast transmissions, while only UM can be used in multicast or broadcast transmissions. For UM, only unidirectional transmissions of multicast and broadcast can be supported.

[0046] The services and functions of the PDCP sublayer for the Uu interface can be supported for sidelinks with the following limitations: out-of-order delivery can be supported only for unicast transmission; and duplication can not be supported on the PC5 interface.

[0047] The SDAP sublayer can provide the following services and functions through the PC5 interface: mapping between QoS flows and sidelink data radio bearers. For each destination, there can be one SDAP entity, representing one of the unicast, multicast, or broadcast traffic types associated with it.

[0048] The RRC sublayer can provide the following services and functions through the PC5 interface: transmission of PC5-RRC messages between peer UEs; maintenance and release of PC5-RRC connections between two UEs; and detection of sidelink radio link failures of PC5-RRC connections based on indications from the MAC or RLC. A PC5-RRC connection can be a logical connection between two UEs for a pair of source 2IDs and destination 2IDs, which can be considered to be established after the corresponding PC5 unicast link is established. There can be a one-to-one correspondence between PC5-RRC connections and PC5 unicast links. For different source 2ID and destination 2ID pairs, a UE can have multiple PC5-RRC connections with one or more UEs. Separate PC5-RRC procedures and messages can be used by a UE to transmit UE capabilities and sidelink configurations, including SL-DRB configuration, to its peer UE. Two peer UEs can use separate bidirectional procedures in both sidelink directions to exchange their own UE capabilities and sidelink configurations.

[0049] Figure 6Example physical signals in the downlink, uplink, and sidelink according to one or more exemplary embodiments of this disclosure are illustrated. A demodulation reference signal (DM-RS) can be used in the downlink, uplink, and sidelink and can be used for channel estimation. The DM-RS is a UE-specific reference signal and can be transmitted along with the physical channel in the downlink, uplink, or sidelink, and can be used for channel estimation and coherent detection of the physical channel. A phase tracking reference signal (PT-RS) can be used in the downlink, uplink, and sidelink and can be used to track the phase and mitigate performance loss due to phase noise. PT-RS is 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 have low density in the frequency domain and high density in the time domain. PT-RS can occur in combination with DM-RS and occurs when the network configures PT-RS to be present. Positioning Reference Signal (PRS) can be used in the downlink for positioning using different positioning techniques. PRS can be used to measure downlink transmission delay by correlating the received signal from the base station with a local copy in the receiver. Channel State Information Reference Signal (CSI-RS) can be used in both the downlink and sidelink. Among other uses, CSI-RS can be used for channel state estimation, Reference Signal Received Power (RSRP) measurement for mobility and beam management, and time / frequency tracking for demodulation. CSI-RS can be specifically configured for the UE, but multiple users can share the same CSI-RS resource. The UE can determine CSI reports and transmit them to the base station in the uplink using PUCCH or PUSCH. CSI reports can be carried in the sidelink MAC CE. Primary Synchronization Signal (PSS) and Secondary Synchronization Signal (SSS) can be used for radio frame synchronization. PSS and SSS can be used during initial access for cell search procedures or for mobility purposes. Sounding Reference Signals (SRS) can be used in the uplink for uplink channel estimation.Similar to CSI-RS, SRS can be used as a QCL reference for other physical channels, allowing them to be configured and transmitted quasi-co-located with SRS. Sidelink PSS (S-PSS) and Sidelink SSS (S-SSS) can be used for sidelink synchronization.

[0050] Figure 7 Examples of Radio Resource Control (RRC) states and transitions between different RRC states are illustrated according to one or more exemplary embodiments of this disclosure. The UE can be in one of three RRC states: RRC connected state 710, RRC idle state 720, and RRC inactive state 730. After power-on, the UE can be in RRC idle state 720, and the UE can use initial access and establish a connection with the network via the RRC connection establishment procedure to perform data transmission and / or make / receive voice calls. Once the RRC connection is established, the UE can be in RRC connected state 710. The UE can use the RRC connection establishment / release procedure 740 to transition from RRC idle state 720 to RRC connected state 710 or from RRC connected state 710 to RRC idle state 720.

[0051] To reduce signaling load and latency caused by frequent transitions from RRC connected state 710 to RRC idle state 720 when the UE transmits frequent small data, RRC inactive state 730 can be used. In RRC inactive state 730, both the UE and gNB can store the AS context. This can result in a faster state transition from RRC inactive state 730 to RRC connected state 710. The UE can use RRC connection recovery / inactivity procedure 760 to transition from RRC inactive state 730 to RRC connected state 710 or from RRC connected state 710 to RRC inactive state 730. The UE can use RRC connection release procedure 750 to transition from RRC inactive state 730 to RRC idle state 720.

[0052] Figure 8 Example frame structures and physical resources are shown according to one or more exemplary embodiments of this disclosure. Downlink, uplink, or sidelink transmissions can be organized into frames with a duration of 10 ms, consisting of 10 1 ms subframes. Each subframe can consist of 1, 2, 4… time slots, wherein the number of time slots in each subframe can depend on the subcarrier spacing of the carriers transmitted over it. The time slot duration can be 14 symbols with a normal cyclic prefix (CP) or 12 symbols with an extended CP, and can be time-scaled as a function of the subcarrier spacing used, such that an integer number of time slots exist in the subframe. Figure 8 The resource grid is shown in the time and frequency domains. Each element of the resource grid, which consists of a time symbol and a frequency subcarrier, is called a resource element (RE). A resource block (RB) can be defined as 12 consecutive subcarriers in the frequency domain.

[0053] In some examples, and in the case of non-slot-based scheduling, packet transmission can occur on a portion of a time slot, such as during 2, 4, or 7 OFDM symbols, which may also be referred to as a time slot. Time slots can be used for low-latency applications, such as URLLC and operation in unlicensed frequency bands. In some embodiments, time slots can also be used for fast and flexible scheduling of services (e.g., preemption of URLLC over eMBB).

[0054] Figure 9 Example component carrier configurations in different carrier aggregation scenarios are illustrated according to one or more exemplary embodiments of this disclosure. In carrier aggregation (CA), two or more component carriers (CCs) can be aggregated. The UE can receive or transmit simultaneously on one or more CCs depending on its capabilities. Figure 9 As shown, CA can be supported for consecutive and non-consecutive CCs on the same or different frequency bands. The gNB and UE can communicate using the serving cell. The serving cell can be associated with at least one downlink CC (e.g., it can be associated with only one downlink CC, or it can be associated with both downlink and uplink CCs). The serving cell can be a primary cell (PCell) or a secondary cell (SCell).

[0055] The UE can use the uplink timing control procedure to adjust the timing of its uplink transmissions. Timing Advance (TA) can be used to adjust the uplink frame timing relative to the downlink frame timing. The gNB can determine the required timing advance setting and provide it to the UE. The UE can use the provided TA to determine its uplink transmission timing relative to the downlink receive timing observed by the UE.

[0056] In RRC connected state, the gNB is responsible for maintaining timing advance to keep L1 synchronized. Serving cells with uplinks applying the same timing advance and using the same timing reference cell are grouped into Timing Advance Groups (TAGs). A TAG can contain at least one serving cell with a configured uplink. The mapping from serving cell to TAG can be configured by RRC. For a primary TAG, the UE can use the PCell as the timing reference cell, except for those with shared spectrum channel access, where the SCell can also be used as the timing reference cell in some cases. In a secondary TAG, the UE can use any active SCell of that TAG as the timing reference cell, and can leave it unchanged unless necessary.

[0057] Pre-updates can be signaled to the UE by the gNB via a MAC CE command. Such a command can restart a TAG-specific timer that indicates whether L1 can be synchronized: when the timer is running, L1 can be considered synchronized; otherwise, L1 can be considered asynchronous (in which case, uplink transmissions may occur only on PRACH).

[0058] A UE with a single timing advance capability for CA can simultaneously receive and / or transmit on multiple CCs corresponding to multiple serving cells (multiple serving cells in a group) sharing the same timing advance. A UE with multiple timing advance capabilities for CA can simultaneously receive and / or transmit on multiple CCs corresponding to multiple serving cells (multiple serving cells in multiple groups). NG-RAN can ensure that each TAG contains at least one serving cell. A UE without CA capability can receive on a single CC and can transmit on a single CC corresponding to only one serving cell (one serving cell in a TAG).

[0059] In the case of CA, the physical layer's multi-carrier characteristics can be exposed to the MAC layer, and each serving cell may require a HARQ entity. When CA is configured, the UE can have an RRC connection with the network. During RRC connection establishment / re-establishment / handover, a serving cell (e.g., PCell) can provide NAS mobility information. Depending on the UE's capabilities, SCells can be configured to form a serving cell set together with the PCell. The serving cell set configured for the UE can consist of one PCell and one or more SCells. Reconfiguration, addition, and removal of SCells can be performed by RRC.

[0060] In a dual-connectivity scenario, a UE can be configured with multiple cells, including a Master Cell Group (MCG) for communicating with the master base station, a Secondary Cell Group (SCG) for communicating with the secondary base station, and two MAC entities: a MAC entity for the MCG for communicating with the master base station, and a MAC entity for the SCG for communicating with the secondary base station.

[0061] Figure 10 Example partial bandwidth configurations and handovers are illustrated according to one or more exemplary embodiments of this disclosure. A UE may be configured with one or more partial bandwidths (BWPs) 1010 on a given member carrier. In some examples, one of the one or more partial bandwidths is active at any given time. The active partial bandwidth may define the UE's operating bandwidth within the cell's operating bandwidth. For initial access, and until the UE's configuration in the cell is received, an initial partial bandwidth 1020 determined based on system information may be used. Utilizing bandwidth adaptation (BA), such as through BWP handover 1040, the UE's receive and transmit bandwidths may not be as large as the cell's bandwidth and may be adjusted. For example, the width may be commanded to change (e.g., shrinking during periods of low activity to save power); the location may be moved in the frequency domain (e.g., to increase scheduling flexibility); and the subcarrier spacing may be commanded to change (e.g., to allow different services). The first active BWP 1020 may be an active BWP for active RRC (re)configuration for a PCell or SCell.

[0062] For each downlink or uplink BWP in the set of downlink or uplink BWPs, the following configuration parameters can be provided to the UE: Subcarrier Spacing (SCS); Cyclic Prefix; Common RB and multiple consecutive RBs; Index of the corresponding BWP-Id in the set of downlink or uplink BWPs; Set of BWP Common Parameters and Set of BWP Specific Parameters. Based on the configured subcarrier spacing and cyclic prefix of the BWP, the BWP can be associated with an OFDM parameter set. For the serving cell, the UE can be provided with a default downlink BWP from the configured downlink BWPs. If the UE is not provided with a default downlink BWP, the default downlink BWP can be the initial downlink BWP.

[0063] A downlink BWP can be associated with a BWP inactivity timer. If the BWP inactivity timer associated with the active downlink BWP expires, and if a default downlink BWP is configured, the UE can perform a BWP handover to the default BWP. If the BWP inactivity timer associated with the active downlink BWP expires, and if no default downlink BWP is configured, the UE can perform a BWP handover to the initial downlink BWP.

[0064] Figure 11 Example four-step contention-based random access procedures and contention-free random access procedures are shown, illustrating some aspects of one or more exemplary embodiments of this disclosure. Figure 12 Example two-step contention-based and contention-free random access procedures are illustrated according to one or more exemplary embodiments of this disclosure. The random access procedure may be triggered by multiple events, such as: initial access from an RRC idle state; RRC connection reconstruction process; arrival of downlink or uplink data during an RRC connected state when the uplink synchronization state is “asynchronous”; arrival of uplink data during an RRC connected state when no PUCCH resource is available for a scheduling request (SR); SR failure; a request from the RRC during synchronization reconfiguration (e.g., handover); transition from an RRC inactive state; establishing time alignment for a second TAG; requesting additional system information (SI); beam failure recovery (BFR); and consistent uplink listen-before-talk (LBT) failure.

[0065] It supports two types of random access (RA) procedures: a 4-step RA type with MSG1 and a 2-step RA type with MSGA. Both types of RA procedures can support, for example, Figure 11 and Figure 12 The examples shown are contention-based random access (CBRA) and contention-free random access (CFRA).

[0066] The UE can select the type of random access at the start of the random access procedure based on network configuration. When no CFRA resources are configured, the UE can use the RSRP threshold to select between the 2-step RA type and the 4-step RA type. When CFRA resources are configured for the 4-step RA type, the UE can perform random access using the 4-step RA type. When CFRA resources are configured for the 2-step RA type, the UE can perform random access using the 2-step RA type.

[0067] The 4-step RA type MSG1 can consist of a preamble on the PRACH. After the MSG1 transmission, the UE can monitor the response from the network within a configured window. For CFRA, the dedicated preamble for MSG1 transmission can be assigned by the network, and the UE can terminate the process upon receiving a Random Access Response (RAR) from the network. Figure 11 The random access procedure is shown in the diagram. For CBRA, upon receiving the random access response, the UE can use the uplink grant scheduled in the random access response to send MSG3, and can, as shown... Figure 11 The monitoring contention resolution is shown in the diagram. If contention resolution fails after (one or more) MSG3 (re)transmissions, the UE can return to MSG1 transmission.

[0068] A 2-step RA type MSGA can include a preamble on the PRACH and a payload on the PUSCH. After the MSGA transmission, the UE can monitor the response from the network within a configured window. For CFRA, dedicated preamble and PUSCH resources can be configured for MSGA transmission, and the UE can terminate the transmission upon receiving a network response. Figure 12 The random access procedure is shown in the diagram. For CBRA, if contention resolution is successful upon receiving a network response, the UE can terminate as follows: Figure 12 The random access procedure is shown in the diagram. If a backoff indication is received in the MSGB, the UE can use the uplink grant scheduled in the backoff indication to perform an MSG3 transmission and can monitor contention resolution. If contention resolution fails after (one or more) MSG3 (re)transmissions, the UE can return to an MSGA transmission.

[0069] Figure 13 Example time and frequency structures of synchronization signals and Physical Broadcast Channel (PBCH) blocks (SSBs) according to one or more exemplary embodiments of this disclosure are shown. An SS / PBCH block (SSB) may consist of a primary synchronization signal and a secondary synchronization signal (PSS, SSS), each occupying one symbol and 127 subcarriers (e.g., Figure 13 The subcarriers are numbered 56 to 182, and PCBH spans 3 OFDM symbols and 240 subcarriers, but leaves an unused portion in the middle of one symbol for SSS, such as... Figure 13 As shown in the diagram, the possible temporal location of the SSB within a half-frame can be determined by the subcarrier spacing, and the period of the half-frame for transmitting the SSB can be configured by the network. During the half-frame, different SSBs can be transmitted in different spatial directions (i.e., using different beams that span the coverage area of ​​the cell).

[0070] The PBCH can be used to carry the Master Information Block (MIB) used by the UE during cell search and initial access procedures. The UE can first decode the PBCH / MIB to receive other system information. The MIB can provide the UE with the parameters required to obtain System Information Block 1 (SIB1), and more specifically, provide the information required to monitor the PDCCH used to schedule the PDSCH carrying SIB1. In addition, the MIB can indicate cell prohibition status information. The MIB and SIB1 can be collectively referred to as the Minimum System Information (SI), and SIB1 can be referred to as the Remaining Minimum System Information (RMSI). Other System Information Blocks (SIBs) (e.g., SIB2, SIB3...SIB10 and SIBpos) can be referred to as other SIs. Other SIs can be broadcast periodically on the DL-SCH, broadcast on demand on the DL-SCH (e.g., upon request from a UE in an RRC idle state, an RRC inactive state, or an RRC connected state), or sent on the DL-SCH in a dedicated manner to UEs in an RRC connected state (e.g., if configured by the network, upon request from a UE in an RRC connected state, or when the UE has an active BWP that is not configured with a common search space).

[0071] Figure 14 Example SSB burst transmissions are illustrated according to one or more exemplary embodiments of this disclosure. An SSB burst may include N SSBs, and each of the N SSBs may correspond to a beam. SSB bursts may be transmitted according to a period (e.g., an SSB burst period). During a contention-based random access procedure, the UE may perform a random access resource selection procedure, whereby the UE first selects an SSB before selecting an RA preamble. The UE may select an SSB with an RSRP higher than a configured threshold. In some embodiments, if no SSB with an RSRP higher than the configured threshold is available, the UE may select any SSB. A set of random access preambles may be associated with an SSB. After selecting an SSB, the UE may select a random access preamble from the set of random access preambles associated with the SSB, and may transmit the selected random access preamble to initiate the random access procedure.

[0072] In some embodiments, beams among the N beams may be associated with CSI-RS resources. The UE can measure the CSI-RS resources and select CSI-RS with an RSRP higher than a configured threshold. The UE can select a random access preamble corresponding to the selected CSI-RS and can transmit the selected random access procedure to begin the random access procedure. If there is no random access preamble associated with the selected CSI-RS, the UE can select a random access preamble corresponding to an SSB that is quasi-in-place with the selected CSI-RS.

[0073] In some embodiments, based on UE measurements and UE CSI reports using CSI-RS resources, the base station can determine the Transmission Configuration Indication (TCI) state and can indicate the TCI state to the UE, whereby the UE can use the indicated TCI state to receive downlink control information (e.g., via PDCCH) or data (e.g., via PDSCH). The UE can use the indicated TCI state to receive data or control information using an appropriate beam. The TCI state indication can use RRC configuration or a combination of RRC signaling and dynamic signaling (e.g., via MAC Control Element (MAC CE) and / or based on field values ​​in downlink control information that schedules downlink transmissions). The TCI state can indicate a quasi-colocation (QCL) relationship between a downlink reference signal such as CSI-RS and a DM-RS associated with a downlink control or data channel (e.g., PDCCH or PDSCH, respectively).

[0074] In some embodiments, the UE can configure itself using a list of up to M TCI states configured with Physical Downlink Shared Channel (PDSCH) configuration parameters to decode the PDSCH based on the detected PDCCH, where the DCI is intended for both the UE and a given serving cell, and M may depend on the UE's capabilities. Each TCI state may contain parameters for configuring the QCL relationship between one or two downlink reference signals and the DM-RS port of the PDSCH, the DM-RS port of the PDCCH, or the CSI-RS port of the CSI-RS resource. This quasi-correspondence relationship may be configured by one or more RRC parameters. The quasi-correspondence type corresponding to each DL RS may take one of the following values: "QCL-TypeA": {Doppler shift, Doppler spread, average delay, delay spread}; "QCL-TypeB": {Doppler shift, Doppler spread}; "QCL-TypeC": {Doppler shift, average delay}; "QCL-type": {spatial reception parameters}. The UE can receive activation commands (e.g., MAC CE) for mapping TCI states to code points in the DCI field.

[0075] Figure 15 Example components of a user equipment and base station for transmission and / or reception are shown, representing some aspects of one or more exemplary embodiments according to this disclosure. In one embodiment, Figure 15 The illustrative components can be considered as illustrative examples of functional blocks of the illustrative base station 1505. In another embodiment, Figure 15 The illustrative components can be considered as illustrative examples of the functional blocks of the illustrative user equipment 1500. Therefore, Figure 15 The components shown are not necessarily limited to user equipment or base stations.

[0076] like Figure 15 As shown, antenna 1510 can be used for the transmission or reception of electromagnetic signals. Antenna 1510 may include one or more antenna elements and can implement different input / output antenna configurations, including Multiple-Input Multiple-Output (MIMO) configurations, Multiple-Input Single-Output (MISO) configurations, and Single-Input Multiple-Output (SIMO) configurations. In some embodiments, antenna 150 can implement a large number of MIMO configurations with dozens or hundreds of antenna elements. Antenna 1510 can implement other multi-antenna techniques such as beamforming. In some examples and depending on the capabilities of UE 1500 or the type of UE 1500 (e.g., low-complexity UE), UE 1500 may support only a single antenna.

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

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

[0079] Processor 1540 may include hardware devices with processing capabilities (e.g., a general-purpose processor, DSP, CPU, microcontroller, ASIC, FPGA, programmable logic device, discrete gate or transistor logic unit, discrete hardware unit, or any combination thereof). In some examples, processor 1540 may be configured to operate memory using a memory controller. In other examples, the memory controller may be integrated into processor 1540. Processor 1540 may be configured to execute computer-readable instructions stored in memory (e.g., memory 1530) to cause UE 1500 or base station 1505 to perform various functions.

[0080] The Central Processing Unit (CPU) 1550 can execute basic arithmetic, logic, control, and input / output (I / O) operations specified by computer instructions stored in memory 1530. User equipment 1500 and / or base station 1505 may include additional peripheral components such as a Graphics Processing Unit (GPU) 1560 and a Global Positioning System (GPS) 1570. The GPU 1560 is dedicated circuitry for rapidly manipulating and modifying memory 1530 to accelerate the processing performance of user equipment 1500 and / or base station 1505. The GPS 1570 can be used, for example, to enable location-based services or other services based on the geographic location of user equipment 1500.

[0081] In some examples, MBS service can be enabled via a single cell transmission. MBS can be transmitted within the coverage of a single cell. One or more multicast / broadcast control channels (e.g., MCCH) and one or more multicast / broadcast data channels (e.g., MTCH) can be mapped on the DL-SCH. Scheduling can be performed by the gNB. Transmissions of multicast / broadcast control channels and multicast / broadcast data channels can be indicated by logical channel-specific RNTIs on the PDCCH. In some examples, a one-to-one mapping between service identifiers such as Temporary Mobile Group Identifiers (TMGI) and RAN-level identifiers such as Group Identifiers (G-RNTIs) can be used to receive DL-SCHs to which multicast / broadcast data channels can be mapped. In some examples, a single transmission can be used for the DL-SCH associated with multicast / broadcast control channel and / or multicast / broadcast data channel transmissions, and can be used without HARQ or RLC retransmission and / or with RLC unacknowledged mode (RLC UM). In other examples, some feedback (e.g., HARQ feedback or RLC feedback) may be used for transmission via multicast / broadcast control channels and / or multicast / broadcast data channels.

[0082] In some examples, for multicast / broadcast data channels, the following scheduling information can be provided on the multicast / broadcast control channel: multicast / broadcast data channel scheduling period, multicast / broadcast data channel open duration (e.g., the duration for which the UE waits to receive a PDCCH after being woken up from DRX), and multicast / broadcast data channel inactivity timer (e.g., the time for the UE to wait for successful decoding of the PDCCH, starting from the most recent successful decoding of the PDCCH indicating the DL-SCH mapped by the multicast / broadcast data channel, and re-entering DRX if it fails).

[0083] In some examples, one or more UE identifiers may be associated with MBS transmissions. These identifiers may include at least one of the following: one or more first RNTIs identifying the transmission of a multicast / broadcast control channel; and one or more second RNTIs identifying the transmission of a multicast / broadcast data channel. The one or more first RNTIs identifying the transmission of a multicast / broadcast control channel may include a Single Cell RNTI (SC-RNTI, or other names may be used). The one or more second RNTIs identifying the transmission of a multicast / broadcast data channel 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. One or more logical channels may include multicast / broadcast control channels. A multicast / broadcast control channel can be a point-to-multipoint downlink channel used to transmit MBS control information from the network to the UE for one or more multicast / broadcast data channels. This channel can be used by a UE that is receiving or interested in receiving MBS. One or more logical channels may include multicast / broadcast data channels. This channel can be a point-to-multipoint downlink channel used to transmit MBS service data from the network.

[0085] In some examples, the UE may use a procedure to notify the RAN that the UE is receiving or is interested in receiving MBS services via the MBS radio bearer, and if so, to notify the 5G RAN of the priority of MBS for unicast reception or MBS service reception in receive-only mode. The UE may transmit messages (e.g., MBS interest indication messages) to notify the RAN that the UE is receiving / interested in receiving or no longer receiving / no longer interested in receiving MBS services. The UE may transmit messages based on one or more messages received from the network (e.g., SIB messages or unicast RRC messages), such as one or more MBS service area identifiers indicating the current and / or adjacent carrier frequencies.

[0086] In some examples, if the UE is able to receive MBS services (e.g., via a single-cell point-to-multipoint mechanism), the UE can consider that MBS service to be part of an MBS service of interest. The UE can be configured to receive or indicate information about MBS services of interest via a bearer associated with the MBS service. Further, in another example, the UE can determine or transmit information that a session of the service is in progress or about to begin. In yet another example, the UE can receive or indicate 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 can be provided on a specific logical channel (e.g., MCCH). The MCCH can carry one or more configuration messages indicating the ongoing MBS session and (corresponding) information about when each session can be scheduled, such as the scheduling period, scheduling window, and start offset. These one or more configuration messages can provide information about neighboring cells transmitting the MBS session, which can take place on the current cell. In some examples, the UE can receive a single MBS service at a time, or receive more than one MBS service in parallel.

[0088] In some examples, MCCH information (e.g., information transmitted in messages sent via the MCCH) can be transmitted periodically using configurable repetition periods. MCCH transmission (along with associated radio resources and MCS) can be indicated on the PDCCH.

[0089] In some examples, changes to MCCH information can occur within a specific radio frame / subframe / slot and / or a modification period can be used. For example, within a modification period, the same MCCH information can be transmitted multiple times, as defined by its scheduling (which is based on repeating periods). The modification period boundary can be defined by an SFN value of SFN mod m = 0, where m is the number of radio frames including the modification period. The modification period can be configured by SIB or RRC signaling.

[0090] In some examples, when the network changes (some) MCCH information, it can notify the UE of the change in the first subframe / slot, which can then be used for MCCH transmission during a recurring period. Upon receiving the change notification, a UE interested in receiving MBS services can begin acquiring the new MCCH information from the same subframe / slot. The UE can apply the previously acquired MCCH information until it acquires the new MCCH information.

[0091] In one example, the System Information Block (SIB) may contain information required to obtain control information associated with the transmission of the MBS. This information may include at least one of the following parameters: one or more Discontinuous Receive (DRX) parameters for scheduling information used to monitor the control information associated with the transmission of the MBS; a scheduling period and offset for scheduling the control information associated with the transmission of the MBS; a modification period for modifying the content of the control information associated with the transmission of the MBS; and repetition information for repeating the control information associated with the transmission of the MBS.

[0092] In one example, the Information Element (IE) can provide configuration parameters indicating, for example, a list of ongoing MBS sessions transmitted via one or more bearers for each MBS session, one or more associated RNTIs (e.g., G-RNTIs, which may use other names), and scheduling information. Configuration parameters may include at least one of the following: one or more timer values ​​for Discontinuous Reception (DRX) (e.g., inactive timers or on-duration timers), RNTIs for scrambling the scheduling and transmission of multicast / broadcast traffic channels (e.g., MTCHs, which may use other names), ongoing MBS sessions, one or more power control parameters, one or more scheduling periods and / or offset values ​​for one or more MBS traffic channels, information about neighboring cell lists, etc.

[0093] In some examples, the UE can monitor a set of PDCCH candidates in one or more configured Control Resource Sets (CORESETs) at configured monitoring times, based on the corresponding search space configuration. A CORESET can include a set of Physical Resource Blocks (PRBs) with a duration of 1 to 3 OFDM symbols. Resource Element Groups (REGs) and Control Channel Elements (CCEs) can be defined within a CORESET, with each CCE comprising a set of REGs. Control channels can be formed by aggregating CCEs. Different code rates for control channels can be achieved by aggregating different numbers of CCEs. Interleaved and non-interleaved CCE-to-REG mappings can be supported in a CORESET.

[0094] In some examples, the information element (IE) MeasIdleConfig can be used to convey to the UE information about the measurements to be performed during RRC Idle (RRC_IDLE) or RRC Inactive (RRC_INACTIVE) states. Example parameters for the MeasIdleConfigIE may include the following. During RRC Idle or RRC Inactive states, additional parameters related to the MBS service / session for the measurements may be used, either additionally or in lieu of one or more of the following parameters. This parameter includes:

[0095] The parameter `absThreshSS-BlocksConsolidation` indicates the merging threshold for L1 measurements used for each RS index. The parameter `beamMeasConfigIdle` indicates the beam level measurement configuration. The parameter `carrierfreq` indicates the NR carrier frequency to be used for measurements during RRC idle or RRC inactivity. The parameter `carrierFreqEUTRA` indicates the E-UTRA carrier frequency to be used for measurements during RRC idle or RRC inactivity. The parameter `deriveSSB-IndexFromCell` indicates whether the UE can use the timing of any detected cell on that frequency to derive the SSB index of all neighboring cells on that frequency. If this field is set to true, the UE can assume that the System Frame Number (SFN) is aligned with the frame boundary between cells on adjacent frequencies. The parameter `frequencyBandList` indicates the list of frequency bands to which NR idle / inactive measurement parameters can be applied. The UE can select the first listed frequency band it supports in the frequency band list field to represent the NR neighboring carrier frequencies. The parameter `includeBeamMeasurements` indicates whether the UE can include beam measurements in NR idle / inactive measurement results. The parameter `maxNrofRS-IndexesToReport` indicates the maximum number of beam indices to include in idle / inactive measurement results. The parameter `measCellListEUTRA` indicates the list of E-UTRA cells for which the UE is requested to measure and report idle / inactive measurements. The parameter `measIdleCarrierListNR` indicates the NR carriers to be measured during RRC idle or RRC inactive periods. The parameter `measIdleDuration` specifies the duration used to perform idle / inactive measurements while the UE is in RRC idle or RRC inactive. The parameter `nrofSS-BlocksToAverage` indicates the average number of SS blocks used for cell measurement derivation. The parameter `qualityThreshold` indicates the quality threshold for the measured cells used to report idle / inactive NR measurements. The parameter `qualityThresholdEUTRA` indicates the quality threshold for the measured cells used to report idle / inactive E-UTRA measurements. The parameter `reportQuantities` indicates which measurements the UE is requested to report in the Idle / Inactive Measurement Report. The parameter `reportQuantitiesEUTRA` indicates which E-UTRA measurements the UE is requested to report in the Idle / Inactive Measurement Report.The parameter `reportQuantityRS-Indexes` indicates which per-beam index measurement information the UE should include in NR idle / inactive measurement results. The parameter `smtc` indicates the measurement timing configuration for inter-frequency measurements. The parameter `ssbSubcarrierSpacing` indicates the subcarrier spacing of the SSB. The parameter `ssb-ToMeasure` indicates the set of SS blocks to be measured during the SMTC measurement duration. The parameter `ss-RSSI-Measurement` indicates the SSB-based RSSI measurement configuration. The parameter `validityAreaList` indicates a list of frequencies and, optionally, a list of cells within which the UE needs to perform measurements while the RRC is in both idle and inactive states for each frequency.

[0096] In some examples, the SIB (e.g., SIB11) may contain information related to idle / inactive measurements. The parameter / IE measIdleConfigSIB can indicate the measurement configuration to be stored and used by the UE while it is in RRC idle or RRC inactive.

[0097] In some examples, during RRC idle state, the UE may not register with a specific cell, and therefore may not have AS context or other information received from the network. The network can initiate an RRC connection release procedure to transition a UE in RRC connected (RRC_CONNECTED) state to RRC idle state. The UE can be periodically woken up (according to the configured DRX period) and can monitor paging messages from the network. The network can reach UEs in RRC idle state via paging messages and notify them of system information changes and other indications via short messages. Both paging messages and short messages can be addressed using P-RNTI on the PDCCH. Paging messages can be sent on the PCCH, and short messages can be sent on the PDCCH.

[0098] In some examples, when RRC is idle, the UE can monitor the paging channel for paging initiated by the CN. In RRC inactive, the UE can monitor the paging channel for paging initiated by the RAN. The UE may not monitor the paging channel continuously. Paging DRX can be used, where a UE in RRC idle or RRC inactive can monitor the paging channel during the paging occupancy (PO) of each DRX cycle.

[0099] In some examples, during RRC idle state, the UE can manage mobility via cell (re)selection based on network configuration. The UE can perform neighboring cell measurements for cell (re)selection.

[0100] In some examples, when transitioning from an RRC connected or RRC inactive state to an RRC idle state, the UE may camp on the cell as a result of cell selection based on the frequency allocated by the RRC in the state transition message.

[0101] In some examples, during RRC idle state, the UE may not transmit in the uplink except for PRACH initiated when the UE wishes to transition to RRC connected state or requests on-demand system information.

[0102] In some examples, the RRC inactive state can be used to reduce network signaling load and decrease latency involved in transitioning to the RRC connected state. In the RRC inactive state, the AS context can be stored by both the UE and the gNB. The state transition from inactive to connected state may be faster than the transition from RRC idle to RRC connected state. In some examples, core network connectivity can be maintained in the RRC inactive state (e.g., the UE can remain in a CM connection).

[0103] In some examples, a UE in an RRC inactive state can be periodically (e.g., according to a configured DRX cycle) woken up and can monitor paging messages from the network. The network can reach UEs in an RRC inactive state via paging messages and can notify UEs in an RRC inactive state of changes in system information and other indications via short messages. Paging messages and short messages can be addressed using P-RNTI on the PDCCH and are transmitted on the PCCH and PDCCH, respectively.

[0104] In some examples, the UE can monitor the paging channel for CN paging using 5G-S-TMSI and RAN paging using full I-RNTI (inactive RNTI). The I-RNTI can be used to identify the suspended UE context of a UE in an RRC inactive state. When a UE moves from an RRC connected state to an RRC inactive state, the network can assign an I-RNTI to the UE in the RRC Release message within the SuspendConfig.

[0105] In some examples, during RRC inactive states, the UE may not transmit in the uplink except for PRACH initiated when the UE wishes to transition to the RRC connected state (to transmit an RRC Resume Request) or to request on-demand system information.

[0106] In some examples, the gNB can send the UE from the RRC connected state to the RRC inactive state by transmitting an RRC release message with a suspend configuration.

[0107] The field suspension configuration can provide the UE with the configuration required for the RRC inactive state, and can indicate the full I-RNTI, short I-RNTI, ran-NotificationAreaInfo, ran-PagingCycle, timer value for triggering periodic RNA updates, etc.

[0108] In some examples, the restoration of a suspended RRC connection can be initiated by an upper layer when the UE needs to transition from an RRC inactive state to an RRC connected state, or by the RRC layer to perform an RNA update, or by a RAN paging from the NG-RAN. The RRC connection restoration process can reactivate AS security and re-establish one or more signaling radio bearers (one or more SRBs) and data radio bearers (one or more DRBs).

[0109] In such Figures 16A to 16E In some examples shown, in response to a request to restore the RRC connection, the network can restore the suspended RRC connection and send the UE to the RRC connection, or it can reject the restoration request and send the UE to RRC inactivity (e.g., using a wait timer), or it can re-suspend the RRC connection and send the UE to RRC inactivity, or it can release the RRC connection and send the UE to RRC idle, or it can instruct the UE to initiate NAS level restoration (in which case the network can send an RRC establishment message). First scenario ( Figure 16A This can lead to a successful RRC connection recovery (e.g., transitioning from RRC inactivity to an RRC connection). The second scenario ( Figure 16B This can cause the RRC connection to revert to its initial state (e.g., transitioning from RRC inactivity to an RRC connection). The third scenario ( Figure 16C This can lead to the recovery of the RRC connection, after which the network releases the RRC connection (e.g., transition from RRC inactivity to RRC idle). The fourth scenario ( Figure 16D This can cause the RRC connection to be restored, followed by a network suspension (e.g., transitioning from RRC inactivity to RRC inactivity). Fifth scenario ( Figure 16E This can lead to RRC connection restoration, followed by network rejection (e.g., transition from RRC inactivity to RRC inactivity). The RRC connection restoration process can trigger a random access procedure. For example, the UE can transmit an RRC restoration request (UL CCCH) message in message 3 (MSG3) or message A (MSGA).

[0110] In some examples, the ResumeCause field may indicate one of the following, or other parameters associated with 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] After receiving a recovery request from the UE, the network can send an RRC Resume (RRCResume)(DCCH) message to resume the suspended RRC connection. The UE can confirm the successful completion of the RRC connection recovery process by sending an RRC Resume Complete (RRCResumeComplete)(DCCH) message.

[0112] In some examples, during RRC inactivity, the UE can remain in a CM connection and can move within an area (RAN Notification Area, RNA) configured by the NG-RAN without notifying the NG-RAN. In this state, the last serving gNB node can maintain the UE context and the NG connection associated with the UE and serving AMF and UPF. If the last serving gNB receives downlink data from the UPF or downlink UE-related signaling from the AMF, it pagees the cell corresponding to that RNA, and if that RNA includes cells of one or more neighboring gNBs, it can send Xn-AP RAN paging to those neighboring gNBs.

[0113] In some examples, a UE in an RRC inactive state can be configured by the last serving NG-RAN node with an RNA (e.g., configured in an RRC release message via suspend configuration), where: the RNA can cover one or more cells and can be contained within the CN registration area. RAN-Based NotificationArea Update (RNAU) can be sent periodically by the UE. In some examples, RNAU can be sent when the UE reselects a cell that does not belong to the configured RNA.

[0114] In some examples, while transitioning the UE to RRC inactivity, the NG-RAN node can configure a periodic RNA update timer value (e.g., t380) for the UE. When this periodic timer expires, the UE can initiate an RRC connection recovery procedure with a recovery reason set to rna-udpate.

[0115] In some examples, a UE in an RRC inactive state can initiate an RNA update procedure (e.g., with the recovery reason set to rna-Update) when it moves outside the configured RNA, i.e., when the serving cell may not belong to the configured ran-NotificationAreaInfo.

[0116] In some examples, when an RNA update request is received from the UE, the receiving gNB can trigger the Xn-AP UE context retrieval procedure to obtain the UE context from the last serving gNB, and can decide to send the UE back to the RRC inactive state, move the UE to the RRC connected state, or send the UE to the RRC idle state.

[0117] In some examples, if the UE accesses a gNB other than the last serving gNB, the receiving gNB can trigger an Xn-AP UE context retrieval procedure to obtain 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 can perform the establishment of a new RRC connection instead of restoring the previous RRC connection.

[0118] In some examples, Multicast Broadcast Service (MBS) can use a Single Cell Point-to-Multipoint (SC-PTM) framework. SC-PTM can be used for eMBMS services, Mission Critical Push-to-Talk (MCPTT), Internet of Things (IoT), and Vehicle-to-Everything (V2X). Example solutions for service continuity and handover procedures do not consider UE and service mobility for MBS services / sessions for UEs in RRC inactive or RRC idle states. Service continuity and mobility of MBS services need to be maintained for UEs in RRC idle and RRC inactive states. Example implementations can achieve service continuity and mobility of MBS services / sessions for UEs in RRC idle and RRC inactive states.

[0119] Given the wide reach of MBS services and the emphasis on power conservation in 5G, maintaining MBS service continuity and mobility for UEs in idle and inactive states is also important, while maximizing commonalities with connected-state mobility. In some examples, this mobility support for idle / inactive UEs may not be required for all MBS services and may not be supported in the same way for all UEs. In some examples, the level of mobility support for MBS services can be configurable per MBS service and / or per UE.

[0120] In some examples, for certain MBS services, such as those with low duty cycles, UEs can receive MBS data in both connected and idle / inactive states, even when they move to other cells. This can be a QoS parameter that can be set for each service and / or each user.

[0121] In some examples, support for service continuity with mobility can be enabled only for UEs in RRC inactive state, or only for UEs in RRC idle mode, or for UEs in both RRC inactive and RRC idle states.

[0122] In some examples, support for Service Continuity (SC) of MBS services and for UEs in an idle / inactive state can typically be QoS parameters that can be configured for each service and / or each UE.

[0123] In some examples, for MBS with the SC option, the geographic area where the UE expects this service can be set via application layer signaling. The UE can use its geographic location or configuration information received from the serving / selected (target) cell to determine whether its target MBS service is available in neighboring cells.

[0124] exist Figure 17 The document illustrates an example procedure for MBS service continuity in RRC inactive or RRC idle states. In some examples, measurements and trigger events can be used to configure the UE, and when the UE moves to the target cell in an RRC idle or RRC inactive state, the UE can indicate its need for MBS service continuity to the RAN.

[0125] In some examples, MBS-SC measurements and triggers can be used to configure a UE in an RRC inactive / idle state to initiate an MBS service continuity procedure. In some examples, measurement threshold types and / or events can be dedicated to MBS service continuity. In some examples, threshold types and / or events can have different values ​​configured for cell (re)selection in RRC idle or RRC inactive states.

[0126] exist Figure 18 The example shown illustrates MBS service continuity options in RRC inactive or RRC idle states. In some examples, once the UE determines that its MBS service continuity requires the RAN's attention, it can initiate a procedure that may or may not require the UE to return to a connected state. In some examples (e.g., Figure 18 Option a) allows a UE in an RRC inactive / idle state to return to the RRC connected state based on observed MBS SC triggering, and the UE can use the connected state mobility procedure for MBS HO to the target cell. In some examples (e.g., Figure 18 Option b) allows a UE in an RRC inactive state to send an update to the RAN based on an observed MBS SC trigger, such as a RAN Notification Area (RNA) update in an RRC recovery request, or other procedures, to indicate its transition to the target cell without leaving the RRC inactive state. In some examples, this procedure may allow the UE's MBS context, which is part of the UE's RAN context, to be shared with the target cell without returning the UE to the connected state. If the MBS configuration (e.g., BWP, subframe, slot duration / format, etc.) differs in the target cell, this information can be included in the RRC signaling returned to the UE, for example, as part of a Suspend Indication message. In some examples (e.g., ... Figure 18Option c) allows a UE in an RRC inactive or RRC idle state to send updates based on observed MBS SC triggering, using RACH-based signaling. This update can indicate information about the UE leaving the source cell towards the target network and the MBS service the UE is receiving. This signaling can reuse message A from a 2-step RACH process or message 3 from a 4-step RACH process. Similar to option b, based on receiving this RACH signal, the RAN can send an RRC message to the UE, such as message B from a 2-step RACH process or message 4 from a 4-step RACH process, including information needed by the UE to determine the MBS service in the target cell. The 2-step RACH process can more efficiently reduce signaling, where message A from the UE can include identifiers for the UE and the target MBS service, and message B from the RAN can include the MBS configuration for the selected service in the target cell.

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

[0128] In such Figure 19 In the example embodiments shown, the UE can be in an RRC inactive or RRC idle state. The UE can transition from an RRC connected state to an RRC inactive or RRC idle state based on receiving an RRC message (e.g., an RRC release message) indicating the release or suspension of RRC configuration. For example, the suspension configuration information element in the RRC release message may indicate one or more RNTIs for identifying the suspended UE context and / or receiving paging information in the RRC inactive state; RAN notification area information; a paging period for RAN-initiated paging; one or more timers for UE operation during the RRC inactive state; etc. The UE transitioning to the RRC inactive state can retain its UE context, and the last serving gNB can retain the UE context. In some examples, a second gNB can 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 can receive the UE context from the last serving gNB using Xn signaling. In some examples, the second gNB can receive the UE context associated with the MBS service from the last serving gNB.

[0129] When in an RRC idle or RRC inactive state, the UE may receive a broadcast message (e.g., a System Information Block (SIB) message such as SIB11) that includes measurement configuration parameters. For example, a broadcast message (e.g., an SIB message, such as 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 RRC idle or RRC inactive states, a list of frequency bands to which the idle / inactive measurement parameters are applied, one or more parameters indicating whether the UE may include beam measurements in the NR idle / inactive measurement results, the duration of the idle / inactive measurements performed as above during RRC idle or RRC inactive states, the number of averaged SS blocks used for cell measurement derivation, one or more subcarrier spacing parameters, etc.

[0130] The UE can determine a service continuity trigger (e.g., a need for a new required cell (re)selection) for one or more MBS services / sessions based on measurement configuration parameters. For example, a service continuity trigger can indicate the need for handover to a target cell for at least one or more MBS services / sessions. For example, the UE can determine a service continuity trigger based on measurements of one or more synchronization signals / PBCH blocks (SSBs) and by comparing values ​​(e.g., averages) determined based on measurements of one or more SSBs (e.g., Reference Signal Received Power (RSRP) and / or Reference Signal Received Quality (RSRQ) of one or more SSBs). In some examples, the service continuity trigger can be MBS service-specific; for example, the thresholds and / or other parameters associated with determining the service continuity trigger can be MBS service-specific and may be different for other services / sessions (e.g., unicast services / sessions). In some examples, the service continuity trigger can be MBS service-specific; for example, the thresholds and / or other parameters associated with determining the service continuity trigger may be different for different MBS services. In some examples, service continuity triggering can be independent of the UE's ongoing service / session and can be UE-specific rather than service / session-specific.

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

[0132] A set of pre-configured / configured random access preambles can be associated with an MBS service / session. The UE can transmit a first message based on the random access procedure, indicating a request for MBS configuration parameters associated with one or more MBS services via a target cell. For example, the UE can transmit the first message based on message 3 (Msg3) in a 4-step random access procedure or message A (MSGA) in a 2-step random access procedure. The first message may include one or more service identifiers (e.g., a Temporary Mobile Group Identifier (TMGI)) indicating the MBS service the UE is receiving from its currently camped cell or the MBS service the UE is interested in receiving from the target cell (e.g., an MBS service requesting service continuity). In some examples, the Quality of Service (QoS) associated with the MBS service / session (e.g., MBS bearer) can 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 can consider the QoS requirements of the MBS bearer in the transmission of the first message or in the admission control of the target cell. The first message may include one or more fields, one or more values ​​of one or more fields associated with the determined service continuity trigger, and / or the need for service continuity for one or more MBS services. For example, one or more fields may include a reason field indicating the reason for transmitting the first message. For example, the first message may be transmitted by other procedures and / or for other reasons, and the value of the reason field may indicate the reason for transmitting the first message. For example, in the case of the UE being in an RRC inactive state, the first message may be an RRC recovery request message with a value of a reason field (e.g., a recovery reason field) indicating that the reason for transmitting the first message is for service continuity associated with one or more MBS services. The value of the reason field may indicate that the reason for transmitting the first message 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 receive MBS configuration parameters and / or information required to receive data associated with MBS services using the target cell. During a 4-step random access procedure, receiving the MBS configuration parameters and / or information required to receive data associated with MBS services using the target cell may be message 4 (Msg4). During a 2-step random access procedure, receiving the MBS configuration parameters and / or information required to receive data associated with MBS services using the target cell may be message B (MsgB). In some examples, the UE may receive receive MBS configuration parameters and / or information required to receive data associated with MBS services from the cell where the UE is currently camped. In some examples, the UE may receive receive MBS configuration parameters and / or information required to receive data associated with MBS services from the target cell.

[0134] The UE may receive MBS configuration parameters and / or information required to receive data associated with MBS services using the target cell as part of an RRC rejection message indicating maintenance in an RRC inactive / idle state. For example, the RRC rejection message may include a suspension configuration information element indicating maintenance / transition in an RRC inactive state, and includes MBS configuration parameters and / or information required to receive data associated with MBS services using the target cell. In some examples, the MBS configuration parameters and / or information required to receive data associated with MBS services using the target cell may indicate and / or may include service identifiers (e.g., TMGI, etc.) of one or more MBS services provided by the target cell, and / or may indicate one or more MBS services permitted by the target cell. The permitted 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 required to receive data associated with MBS services using the target cell may include first configuration parameters for receiving control information (e.g., via MCCH) for receiving MBS data from the target cell. The first configuration parameter may include scheduling information for receiving control information (e.g., the period of control information transmission by the target cell). In some examples, the MBS configuration parameters and / or information required to receive data associated with MBS services using the target cell may include the BWP identifier of the target cell for receiving control information and / or data for MBS services, a parameter set associated with MBS services (e.g., a parameter set for MBS data / control reception), a control resource set (CORESET) for receiving scheduling information for MBS data / control, etc.

[0135] The UE can receive data associated with MBS service via the target cell using MBS configuration parameters and / or information. The UE can remain in RRC idle state or RRC inactive state and can remain in RRC connected state without transitioning to RRC connected state.

[0136] In one embodiment, a user equipment (UE) in Radio Resource Control (RRC) state can receive a broadcast message including measurement configuration parameters, where the RRC state can be either an RRC inactive state or an RRC idle state. The UE can determine a service continuity trigger for one or more multicast broadcast services (MBS) based on the measurement configuration parameters. In response to determining a service continuity trigger for one or more MBS services, the UE can initiate a random access procedure, which includes transmitting a first message via a target cell indicating a request for MBS configuration parameters associated with one or more MBS services. The UE can receive one or more MBS configuration parameters based on the transmitted first message. The UE can receive data associated with one or more MBS services via the target cell based on the MBS configuration parameters while remaining in the RRC state.

[0137] In some embodiments, a broadcast message may be a System Information Block (SIB) message.

[0138] In some embodiments, the measurement configuration parameters may include one or more of the following: one or more thresholds, one or more carrier frequencies for measurement, one or more frequency band lists, one or more beam-related measurement parameters, one or more durations for measurement, one or more cell lists for measurement, and a plurality of synchronization signal blocks (SSBs) for cell measurement derivation.

[0139] In some embodiments, determining 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 with one or more thresholds.

[0140] In some embodiments, the first message may include a reason field, the value of which indicates at least one of the following: the first message is transmitted due to a service continuity trigger; and the first message is transmitted 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 recovery request message; and the values ​​of one or more fields in the RRC recovery 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 recovery reason field. In some embodiments, receiving one or more MBS configuration parameters may be via an RRC rejection message indicating that the UE remains in the RRC inactive state.

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

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

[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 where the UE is camped. In some embodiments, one or more MBS configuration parameters may indicate one or more first service identifiers of one or more MBS service identifiers, wherein the one or more first service identifiers are provided by the target cell.

[0145] In some embodiments, the quality of service associated with an MBS bearer that is associated with an MBS service in one or more MBS services can indicate the level of service continuity requirements for the MBS bearer.

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

[0147] In some embodiments, the first message may be transmitted via message 3 in the four-step random access procedure. In some embodiments, one or more MBS configuration parameters may be received via message 4 in the four-step random access procedure.

[0148] In some embodiments, a first message is transmitted via message A in the two-step random access procedure. In some embodiments, one or more MBS configuration parameters may be received via message B in the two-step random access procedure.

[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, wherein the RRC release message may include one or more MBS service continuity parameters. In some embodiments, the RRC release message may include a suspend configuration information element indicating a transition to an RRC inactive state and including one or more MBS service continuity parameters. In some embodiments, the transmission of the first message may be based on one or more MBS service continuity parameters.

[0150] The exemplary blocks and modules described in this disclosure with respect to various example embodiments may be implemented or performed using a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. Examples of general-purpose processors include, but are not limited to, microprocessors, any conventional processor, controllers, microcontrollers, or state machines. In some examples, 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 combined with a DSP core, or any other such configuration).

[0151] The functions described in this disclosure can be implemented in hardware, software executed by a processor, firmware, or any combination thereof. Instructions or code can be stored or transmitted on a computer-readable medium for implementing these functions. Other examples of implementing the functions disclosed herein are also within the scope of this disclosure. Implementation of functions can be via physically co-located or distributed elements (e.g., in different locations), including distributions such that partial functions are implemented in 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 disk (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) and can be accessed by a general-purpose or special-purpose computer, or a general-purpose or special-purpose processor. In some examples, software / program code can be transmitted from a remote source (e.g., a website, server, etc.) using coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave. In such examples, coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are within the scope of the media definition. The combinations of the above examples are also within the scope of computer-readable media.

[0153] As used in this disclosure, the use of the term "or" in a list of items indicates a comprehensive list. A list of items may be prefixed with phrases such as "at least one" or "one or more." For example, a list of at least one of A, B, or C includes A or B or C or AB (i.e., A and B) or AC or BC or ABC (i.e., A and B and C). Furthermore, as used in this disclosure, a list of conditions prefixed with the phrase "based on" should not be interpreted as "based only on" the set of conditions, but rather as "at least partially based on" the set of conditions. For example, a result described as "based on condition A" may be based on both condition A and condition B without departing from the scope of this disclosure.

[0154] In this specification, the terms "comprising," "containing," or "including" are used interchangeably and have the same meaning, and are interpreted as inclusive and open-ended. The terms "comprising," "containing," or "including" may precede a list of elements and indicate that at least all listed elements are present, but other elements not listed may also be present. For example, if A includes B and C, then {B, C} and {B, C, D} are both within the scope of A.

[0155] With reference to the accompanying drawings, this disclosure describes example configurations that do not represent all possible examples or all configurations within the scope of this disclosure. The term "exemplary" should not be construed as "preferred" or "advantageous compared to other examples," but rather as "illustration, instance, or example." By reading this disclosure, including the description of embodiments and accompanying drawings, those skilled in the art will understand that alternative embodiments can be used to implement the techniques disclosed herein. Those skilled in the art will appreciate that the embodiments described herein or certain features of the embodiments can be combined to obtain other embodiments for practicing the techniques described in this disclosure. Therefore, this disclosure is not limited to the examples and designs described herein, but should be accorded the broadest scope consistent with the principles and novel features disclosed herein.

[0156] Clause 1. Methods for maintaining service continuity include: A user equipment (UE) in a Radio Resource Control (RRC) state receives a broadcast message including measurement configuration parameters, wherein the RRC state corresponds to at least one of an RRC inactive state and an RRC idle state; Based on the measurement configuration parameters, determine the service continuity trigger for one or more multicast broadcast service (MBS) services; Based on the determined service continuity trigger, a random access procedure (RAP) is initiated, wherein initiating the RAP includes transmitting a first message indicating a request for MBS configuration parameters associated with the one or more MBS services; In response to transmitting the first message, receive one or more MBS configuration parameters; and While remaining in the RRC state, data associated with the one or more MBS services is received via the target cell based on the MBS configuration parameters.

[0157] Clause 2. The method as described in Clause 1, wherein the broadcast message is a System Information Block (SIB) message.

[0158] Clause 3. The method as described in Clause 1, wherein the measurement configuration parameters include at least one of the following: one or more thresholds, carrier frequency for measurement, frequency band list, beam-related measurement parameters, duration for measurement, cell list for measurement, and multiple synchronization signal blocks (SSBs) for cell measurement derivation.

[0159] Clause 4. The method as described in Clause 1, wherein determining the service continuity trigger includes measuring one or more synchronization signal blocks (SSBs) and comparing the received signal strength of the one or more SSBs with one or more thresholds.

[0160] Clause 5. The method as described in Clause 1, wherein the first message includes a reason field, the reason field having information including at least one of the following: The first message is transmitted in response to the service continuity trigger; and The first message is transmitted in order to request the configuration parameters of the Multicast Broadcast Service (MBS).

[0161] Clause 6. The method as described in Clause 1, wherein the Radio Resource Control (RRC) corresponds to an inactive state, wherein the first message is an RRC recovery request message, wherein the value of one or more fields in the RRC recovery request message indicates the request for the one or more multicast broadcast service (MBS) configuration parameters while remaining in the RRC inactive state.

[0162] Clause 7. The method as described in Clause 6, wherein the one or more fields include a recovery reason field.

[0163] Clause 8. The method as described in Clause 6, wherein receiving the 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 the RRC inactive state.

[0164] Clause 9. The method as described in Clause 1, wherein the one or more multicast broadcast service (MBS) configuration parameters include one or more first parameters for receiving control information.

[0165] Clause 10. The method as described in Clause 1, wherein the one or more multicast broadcast service (MBS) configuration parameters include at least one of a partial bandwidth identifier, a control resource set, and a parameter set associated with the one or more MBS services.

[0166] Clause 11. The method as described in Clause 1, wherein the first message includes one or more service identifiers associated with one or more multicast broadcast services (MBS) provided by the current cell in which the user equipment (UE) is camped.

[0167] Clause 12. The method as described in Clause 11, wherein the one or more multicast broadcast service (MBS) configuration parameters indicate one or more first service identifiers of one or more MBS service identifiers, and wherein the one or more first service identifiers are associated with a target cell.

[0168] Clause 13. The method as described in Clause 1, wherein the Quality of Service (QoS) associated with the multicast broadcast service (MBS) bearer associated with the MBS service in one or more MBS services indicates the level of service continuity requirements of the MBS bearer.

[0169] Clause 14. The method as described in Clause 1, wherein the random access procedure includes transmitting a random access preamble to indicate that the random access procedure is associated with multicast broadcast service (MBS) service continuity.

[0170] Clause 15. The method as described in Clause 1, wherein transmitting the first message includes transmitting the first message via message 3 in a four-step random access procedure.

[0171] Clause 16. The method as described in Clause 15, wherein receiving the one or more multicast broadcast service (MBS) configuration parameters includes receiving the MBS configuration parameters via message 4 in a four-step random access procedure.

[0172] Clause 17. The method as described in Clause 1, wherein transmitting the first message includes transmitting the first message via message A in a two-step random access procedure.

[0173] Clause 18. The method as described in Clause 17, wherein receiving the one or more multicast broadcast service (MBS) configuration parameters includes receiving the MBS configuration parameters via message B in the two-step random access procedure.

[0174] Clause 19. The method of Clause 1 further includes receiving a Radio Resource Control (RRC) release message indicating a transition to the RRC inactive state or the RRC idle state, wherein the RRC release message includes one or more multicast broadcast service (MBS) service continuity parameters.

[0175] Clause 20. The method as described in Clause 19, wherein the Radio Resource Control (RRC) Release message includes a Suspension Configuration Information element indicating a transition to the RRC Inactive state, and includes the one or more Multicast Broadcast Service (MBS) service continuity parameters.

[0176] Clause 21. The method as described in Clause 19, wherein the transmission of the first message is based on the service continuity parameters of the one or more Multicast Broadcast Services (MBS).

[0177] Clause 22. A device for use in wireless communication, comprising: An antenna, used to transmit electromagnetic signals; Memory, which is used to hold computer-readable code; and A processor for executing computer-readable code that causes the device to: A broadcast message including measurement configuration parameters is received by a measurement (UE) in a Radio Resource Control (RRC) state, wherein the RRC state corresponds to at least one of an RRC inactive state and an RRC idle state; Based on the measurement configuration parameters, determine the service continuity trigger for one or more multicast broadcast service (MBS) services; In response to the determined service continuity trigger, a random access procedure (RAP) is initiated, wherein initiating the RAP includes transmitting a first message indicating a request for MBS configuration parameters associated with the one or more MBS services; In response to transmitting the first message, receive one or more MBS configuration parameters; and While remaining in the RRC state, data associated with the one or more MBS services is received via the target cell based on the MBS configuration parameters.

[0178] Clause 23. The apparatus as described in Clause 22, wherein the broadcast message is a System Information Block (SIB) message.

[0179] Clause 24. The apparatus as described in Clause 22, wherein the measurement configuration parameters include at least one of the following: one or more thresholds, a carrier frequency for measurement, a list of frequency bands, beam-related measurement parameters, a duration for measurement, a list of cells for measurement, and a plurality of synchronization signal blocks (SSBs) for cell measurement derivation.

[0180] Clause 24. The method as described in Clause 22, wherein determining the service continuity trigger comprises measuring one or more synchronization signal blocks (SSBs) and comparing the received signal strength of the one or more SSBs with one or more thresholds.

[0181] Clause 25. The apparatus of Clause 22, wherein the first message includes information, the information including an indication of at least one of: the first message being transmitted in response to the service continuity trigger, or the first message being transmitted to request the multicast broadcast service (MBS) configuration parameters.

[0182] Clause 26. The apparatus of Clause 22, wherein the Radio Resource Control (RRC) corresponds to an inactive state, wherein the first message is an RRC recovery request message, and wherein the value of one or more fields in the RRC recovery request message indicates the request for configuration parameters of the one or more multicast broadcast services (MBS) while remaining in the RRC inactive state.

[0183] Clause 27. The apparatus as described in Clause 26, wherein the one or more fields include a recovery reason field.

[0184] Clause 28. The apparatus as described in Clause 26, wherein receiving the 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 the RRC inactive state.

[0185] Clause 29. The apparatus as described in Clause 22, wherein the one or more multicast broadcast service (MBS) configuration parameters include one or more first parameters for receiving control information.

[0186] Clause 30. The apparatus as described in Clause 22, wherein the configuration parameters of the one or more multicast broadcast services (MBS) include at least one of a partial bandwidth identifier, a control resource set, and a parameter set associated with the one or more MBS services.

[0187] Clause 31. The apparatus as described in Clause 22, wherein the first message includes one or more service identifiers associated with one or more multicast broadcast services (MBS) provided by the current cell in which the user equipment (UE) is camped.

[0188] Clause 32. The apparatus as described in Clause 31, wherein 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 wherein the one or more first service identifiers are associated with a target cell.

[0189] Clause 33. The apparatus as described in Clause 22, wherein the Quality of Service (QoS) associated with the multicast broadcast service (MBS) bearer associated with the MBS service in one or more MBS services indicates the level of service continuity requirements of the MBS bearer.

[0190] Clause 34. The apparatus as described in Clause 22, wherein the random access procedure includes transmitting a random access preamble to indicate that the random access procedure is associated with multicast broadcast service (MBS) service continuity.

[0191] Clause 35. The apparatus as described in Clause 22, wherein the apparatus transmits the first message according to a random access procedure.

[0192] Clause 36. The apparatus as described in Clause 22, wherein the apparatus is further configured to transmit a Radio Resource Control (RRC) release message indicating a transition to the RRC inactive state or the RRC idle state, wherein the RRC release message includes one or more multicast broadcast service (MBS) service continuity parameters.

[0193] Clause 37. The apparatus as described in Clause 36, wherein the Radio Resource Control (RRC) Release message includes a Suspension Configuration Information element indicating a transition to the RRC Inactive state, and includes the one or more Multicast Broadcast Service (MBS) service continuity parameters.

[0194] Clause 38. Methods for maintaining service continuity include: Transmit a broadcast message including measurement configuration parameters to a user equipment (UE) in a Radio Resource Control (RRC) state, wherein the RRC state of the UE corresponds to at least one of an RRC inactive state and an RRC idle state; The UE receives a first message indicating a request for MBS configuration parameters associated with one or more MBS services; In response to transmitting the first message, the one or more MBS configuration parameters are transmitted to the UE; and While remaining in the RRC state, data associated with the one or more MBS services is transmitted via the target cell based on the MBS configuration parameters.

[0195] Clause 39. The method as described in Clause 38, wherein the broadcast message is a System Information Block (SIB) message.

[0196] Clause 40. The method as described in Clause 38, wherein the measurement configuration parameters include at least one of the following: one or more thresholds, carrier frequency for measurement, frequency band list, beam-related measurement parameters, duration for measurement, cell list for measurement, and multiple synchronization signal blocks (SSBs) for cell measurement derivation.

[0197] Clause 41. The method as described in Clause 38, wherein the first message includes a reason field having information indicating at least one of the following: the first message is transmitted in response to a service continuity trigger, or the first message is transmitted to request configuration parameters for the multicast broadcast service (MBS).

[0198] Clause 42. The method as described in Clause 38, wherein the Radio Resource Control (RRC) corresponds to an inactive state, wherein the first message is an RRC recovery request message, wherein the value of one or more fields in the RRC recovery request message indicates the request for the one or more multicast broadcast service (MBS) configuration parameters while remaining in the RRC inactive state.

[0199] Clause 43. The method as described in Clause 38, wherein transmitting the 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 the RRC inactive state.

[0200] Clause 44. The method as described in Clause 38, wherein the one or more multicast broadcast service (MBS) configuration parameters include one or more first parameters for receiving control information.

[0201] Clause 45. The method as described in Clause 38, wherein the one or more multicast broadcast service (MBS) configuration parameters include at least one of a partial bandwidth identifier, a control resource set, and a parameter set associated with the one or more MBS services.

[0202] Clause 46. The method as described in Clause 38, wherein the first message includes one or more service identifiers associated with one or more multicast broadcast services (MBS) provided by the current cell in which the user equipment (UE) is camped.

[0203] Clause 47. The method as described in Clause 38, wherein 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 wherein the one or more first service identifiers are associated with a target cell.

[0204] Clause 48. The method as described in Clause 38, wherein the Quality of Service (QoS) associated with the multicast broadcast service (MBS) bearer associated with the MBS service in one or more MBS services indicates the level of service continuity requirements for the MBS bearer.

[0205] Clause 49. The method as described in Clause 38, wherein the random access procedure includes transmitting a random access preamble to indicate that the random access procedure is associated with multicast broadcast service (MBS) service continuity.

[0206] Clause 50. The method as described in Clause 38, wherein transmitting the first message includes transmitting the first message in accordance with a random access procedure.

[0207] Clause 51. The method of Clause 38 further includes transmitting a Radio Resource Control (RRC) release message indicating a transition to the RRC inactive state or the RRC idle state, wherein the RRC release message includes one or more multicast broadcast service (MBS) service continuity parameters.

[0208] Clause 52. The method as described in Clause 51, wherein the Radio Resource Control (RRC) Release message includes a Suspension Configuration Information element indicating a transition to the RRC Inactive state, and includes the one or more Multicast Broadcast Service (MBS) service continuity parameters.

[0209] Clause 53. A device for use in wireless communication, comprising: An antenna, used to transmit electromagnetic signals; Memory, which is used to hold computer-readable code; and A processor for executing computer-readable code that causes the device to: A broadcast message including configuration parameters is received by a measurement (UE) in a Radio Resource Control (RRC) state, wherein the RRC state of the UE corresponds to at least one of an RRC inactive state and an RRC idle state; The UE receives a first message indicating a request for MBS configuration parameters associated with one or more MBS services; In response to transmitting the first message, the one or more MBS configuration parameters are transmitted to the UE; and While remaining in the RRC state, data associated with the one or more MBS services is transmitted via the target cell based on the MBS configuration parameters.

[0210] Clause 54. The apparatus as described in Clause 53, wherein the broadcast message is a System Information Block (SIB) message.

[0211] Clause 55. The apparatus as described in Clause 53, wherein the measurement configuration parameters include at least one of the following: one or more thresholds, a carrier frequency for measurement, a list of frequency bands, beam-related measurement parameters, a duration for measurement, a list of cells for measurement, and a plurality of synchronization signal blocks (SSBs) for cell measurement derivation.

[0212] Clause 56. The apparatus of Clause 53, wherein the first message includes a cause field having information indicating at least one of the following: the first message is transmitted in response to a service continuity trigger, or the first message is transmitted to request configuration parameters for the multicast broadcast service (MBS).

[0213] Clause 57. The apparatus as described in Clause 53, wherein the Radio Resource Control (RRC) corresponds to an inactive state, wherein,

[0214] The first message is an RRC recovery request message, wherein,

[0215] The value of one or more fields in the RRC recovery request message indicates a request for one or more multicast broadcast service (MBS) configuration parameters while remaining in an RRC inactive state.

[0216] Clause 58. The apparatus as described in Clause 53, wherein the apparatus is further configured to transmit a Radio Resource Control (RRC) Reject message corresponding to an instruction to remain in the RRC inactive state.

[0217] Clause 59. The apparatus as described in Clause 53, wherein the one or more multicast broadcast service (MBS) configuration parameters include one or more first parameters for receiving control information.

[0218] Clause 60. The apparatus as described in Clause 53, wherein the configuration parameters of the one or more multicast broadcast services (MBS) include at least one of a partial bandwidth identifier, a control resource set, and a parameter set associated with the one or more MBS services.

[0219] Clause 61. The apparatus as described in Clause 53, wherein the first message includes one or more service identifiers associated with one or more multicast broadcast services (MBS) provided by the current cell in which the user equipment (UE) is camped.

[0220] Clause 62. The apparatus as described in Clause 53, wherein 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 wherein the one or more first service identifiers are associated with a target cell.

[0221] Clause 63. The apparatus as described in Clause 53, wherein the Quality of Service (QoS) associated with the multicast broadcast service (MBS) bearer associated with the MBS service in one or more MBS services indicates the level of service continuity requirements of the MBS bearer.

[0222] Clause 64. The apparatus as described in Clause 53, wherein the random access procedure includes transmitting a random access preamble to indicate that the random access procedure is associated with multicast broadcast service (MBS) service continuity.

[0223] Clause 65. The apparatus as described in Clause 53, wherein the apparatus is further configured to transmit the first message in accordance with a random access procedure.

[0224] Clause 66. The apparatus as described in Clause 53, wherein the apparatus is further configured to transmit a Radio Resource Control (RRC) release message indicating a transition to the RRC inactive state or the RRC idle state, wherein the RRC release message includes one or more multicast broadcast service (MBS) service continuity parameters.

[0225] Clause 67. The apparatus as described in Clause 53, wherein the Radio Resource Control (RRC) Release message includes a Suspension Configuration Information element indicating a transition to the RRC Inactive state, and includes the one or more Multicast Broadcast Service (MBS) service continuity parameters.

[0226] This application claims the benefit of U.S. Provisional Application No. 63 / 076,704, filed September 10, 2020, entitled “SYSTEM AND METHOD FOR MAINTAININGMULTICAST BROADCAST SERVICE CONTINUITY IN IDLE AND INACTIVE STATES”. U.S. Provisional Application No. 63 / 076,704 is incorporated herein by reference.

Claims

1. A method for a user equipment to continue receiving one or more multicast broadcast services, comprising: Receive configuration messages associated with the one or more multicast broadcast services, the configuration messages being used by the user equipment in a radio resource control inactive state or a radio resource control idle state; Based on the configuration message, a trigger is determined to transition from the Radio Resource Control inactive state or the Radio Resource Control idle state to the Radio Resource Control connected state to continue receiving the one or more multicast broadcast services; Based on the triggering of the transition from the Radio Resource Control (RRC) inactive state or the RRC idle state to the RRC connected state, data associated with the one or more multicast broadcast services is received via the target cell, wherein... Determining the trigger for transitioning from the Radio Resource Control (RFC) inactive state or the RFC idle state to the RFC connected state includes: determining the trigger based on a comparison between the serving cell's reference signal received power or reference signal received quality and a threshold. The threshold for at least one of the reference signal received power or reference signal received quality is configured per multicast broadcast service session.

2. A method by which a network device allows a user device to continue receiving one or more multicast broadcast services, including: Transmit a configuration message associated with the one or more multicast broadcast services, the configuration message being used by the user equipment in a radio resource control inactive state or a radio resource control idle state to determine a trigger for transitioning from the radio resource control inactive state or the radio resource control idle state to a radio resource control connected state, or even to continue receiving the one or more multicast broadcast services via a target cell. Transmit data associated with the one or more multicast broadcast services. The triggering of the transition from the Radio Resource Control (RRC) inactive state or the RRC idle state to the RRC connected state is determined based on a comparison between the serving cell's reference signal received power or reference signal received quality and a threshold. The threshold for at least one of the reference signal reception power or reference signal reception quality is configured for each multicast broadcast service session.

3. User equipment, including circuitry, said circuitry being configured to: Receive configuration messages associated with one or more multicast broadcast services, the configuration messages being used by the user equipment in a radio resource control inactive state or a radio resource control idle state; Based on the configuration message, a trigger is determined to transition from the Radio Resource Control inactive state or the Radio Resource Control idle state to the Radio Resource Control connected state to continue receiving the one or more multicast broadcast services; as well as Based on the triggering of the transition from the Radio Resource Control (RRC) inactive state or the RRC idle state to the RRC connected state, data associated with the one or more multicast broadcast services is received via the target cell, wherein... Determining the trigger for transitioning from the Radio Resource Control (RFC) inactive state or the RFC idle state to the RFC connected state includes: determining the trigger based on a comparison between the serving cell's reference signal received power or reference signal received quality and a threshold. The threshold for at least one of the reference signal received power or reference signal received quality is configured per multicast broadcast service session.

4. A network device, including circuitry, said circuitry being configured to: Transmit a configuration message associated with one or more multicast broadcast services, the configuration message being used by a user equipment (UE) in a Radio Resource Control (RFC) inactive or Radio Resource Control (RRC) idle state to determine a trigger for transitioning from the RRC inactive or RRC idle state to a RRC connected state, and even to continue receiving the one or more multicast broadcast services via a target cell; and Transmit data associated with the one or more multicast broadcast services. in, The triggering of the transition from the Radio Resource Control (RRC) inactive state or the RRC idle state to the RRC connected state is determined based on a comparison between the serving cell's reference signal received power or reference signal received quality and a threshold. The threshold for at least one of the reference signal reception power or reference signal reception quality is configured for each multicast broadcast service session.

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