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

Abstract

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

Description

Technical Field

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

Background Art

[0002] Generally, a computing device and a communication network can be used for information exchange. In general applications, a computing device can request / send data to another computing device via a communication network. More specifically, a computing device can utilize a wireless communication network to exchange information or establish a communication channel.

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

Summary of the Invention

Means for Solving the Problems

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

Brief Description of the Drawings

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DETAILED DESCRIPTION

[0006] FIG. 1 shows an example of a mobile communication system 100 according to some aspects of one or more exemplary embodiments of the present disclosure. The mobile communication system 100 can be operated by a wireless communication system operator such as a mobile network operator (MNO), a private network operator, a multiple system operator (MSO), an Internet of Things (IoT) network operator, etc., and can provide services such as voice, data (e.g., wireless Internet access), message transmission, vehicular-to-everything (V2X) communication services for automotive driving communication services, safety services, mission-critical services, IoT, industrial IoT (IIoT), etc. services in residential, commercial, or industrial environments.

[0007] In the mobile communication system 100, various types of applications with different requirements in terms of latency, reliability, throughput, etc. may be possible. Examples of applicable applications include enhanced Mobile Broadband (eMBB), Ultra-Reliable Low-Latency Communications (URLLC), and massive Machine Type Communication (mMTC). eMBB has a high peak data rate and can support a stable connection with an appropriate rate for cell-edge users. URLLC has strict requirements regarding latency and reliability and can support applications with moderate requirements regarding data rate. Exemplary mMTC applications include networks of numerous IoT devices that are only sporadically active and transmit only small data payloads.

[0008] The mobile communication system 100 may include a Radio Access Network (RAN) portion and a core network portion. The example shown in FIG. 1 illustrates a next-generation RAN (NG-RAN) 105 and a 5G core network (5G-CN) 110 as examples of the RAN and the core network, respectively. Other examples of the RAN and the core network may also be implemented without departing from the scope of the present disclosure. Other examples of the RAN include Evolved Universal Terrestrial Radio Access Network (EUTRAN), Universal Terrestrial It includes Radio Access Network (UTRAN), etc. Other examples of the core network include Evolved Packet Core (EPC), UMTS Core Network (UCN), etc. The RAN implements Radio Access Technology (RAT) and is between user terminals (UEs) 125 and the core network. Such RATs include New Radio (NR), Long Term Evolution (LTE) also called Evolved Universal Terrestrial Radio Access (EUTRA), Universal Mobile Telecommunication System (UMTS), etc. The RAT of the exemplary mobile communication system 100 can be NR. The core network is between the RAN and one or more external networks (e.g., data networks) and is responsible for functions such as mobility management, authentication, session management, bearer setup, applications with different QoS (Quality of Services), etc. The functional layer between the UE 125 and the RAN (e.g., NG-RAN 105) can be called the access stratum (AS), and the functional layer between the UE 125 and the core network (e.g., 5G-CN 110) can be called the non-access stratum (NAS).

[0009] UEs 125 may include a wireless transmission and reception method for communication with one or more nodes within the RAN, one or more relay nodes, or one or more other UEs, etc. Examples of UEs include, but are not limited to, smartphones, tablets, laptops, computers, in-vehicle wireless transmission and / or reception units, V2X or vehicle-to-vehicle (V2V) devices, wireless sensors, IoT devices, IIoT devices, etc. Other names may also be used for UEs, such as Mobile Station (MS), terminal device, terminal node, client device, mobile device, etc. Furthermore, UEs 125 may also include components or sub-components incorporated into other devices such as automobiles to provide a wireless communication function with nodes within the RAN as described herein. Such other devices may have other functionality or multiple functionalities in addition to wireless communication.

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

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

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

[0013] The gNBs 115 and ng-eNBs 120 can also be connected to the 5GC 110 via the NG interface, more specifically 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 NG-U inte The transport network layer of the base can be built based on IP transport. 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 an unguaranteed transfer of user plane PDUs between the NG-RAN node and the UPF. The transport network layer of the NG-C interface can be built based on IP transport. For reliable transfer 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 transfer of application layer messages. In transport, point-to-point transmission of the IP layer can be used for the transfer of signaling PDUs. The NG-C interface can provide the following functions: NG interface management, UE context management, UE mobility management, transfer of NAS messages, paging, PDU session management, configuration transfer, and warning message transmission.

[0014] gNB 115 or ng-eNB 120 may host one or more of the following functions: radio bearer control, radio admission control, connection mobility control, dynamic allocation of resources to UEs in both uplink and downlink (e.g., scheduling), IP and Ethernet header compression, encryption, and data integrity protection, selection of the AMF in UE attachment when routing from the information provided by the UE to the AMF cannot be determined, routing of user plane data towards the UPF, routing of control plane information towards the AMF, connection setup and release, scheduling and transmission of paging messages, scheduling and transmission of system broadcast information (e.g., issued from the AMF), measurement and measurement result reporting configuration for mobility and scheduling, transport level packet marking in the uplink, session management, support for network slicing, QoS flow management and mapping to data radio bearers, support for UEs in RRC inactive state, delivery function for NAS messages, sharing of radio access networks, dual connectivity, tight interworking between NR and E-UTRA, security retention and radio configuration for user plane 5G System (5GS) Cellular IoT (CIoT) optimization.

[0015] AMF 130 may host one or more of the following functions: NAS signaling termination, NAS signaling security, AS security control, CN node - to - node signaling for mobility between 3GPP (registered trademark) access networks, idle mode UE reachability (including control and execution of paging re - transmission), registration area management, support for intra - system and inter - system mobility, access authentication, access authorization including checking of roaming rights, mobility management control (subscription and policy), support for network slicing, selection of the session management function (SMF), selection for 5GS CIoT optimization.

[0016] The UPF 135 may host one or more of the following functions: an anchor point for Intra- / Inter-RAT mobility (if applicable), an external PDU session point for the interconnection with the data network, packet routing and forwarding, packet inspection and enforcement of user plane part policy rules, traffic usage reporting, an uplink classifier for supporting the routing of traffic flows to the data network, a branching point for supporting multi-home PDU sessions, QoS handling for the user plane, such as packet filtering, gating, UL / DL rate enforcement, uplink traffic verification (mapping from service data flow (SDF) to QoS flow), downlink packet buffering and downlink data notification triggering.

[0017] As shown in Figure 1, the NG-RAN 105 may support the 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) may be called a side link. The side link transmission and reception in the PC5 interface can be supported regardless of which RRC state the UE 125 is in when the UE 125 is within the NG-RAN 105 coverage, and when the UE 125 is outside the NG-RAN 105 coverage. The support for V2X services via the PC5 interface may be provided by NR side link communication and / or V2X side link communication.

[0018] PC5-S signaling can be used for the establishment of unicast links by direct communication request / accept messages. The UE can generate its own source layer-2 ID for the PC5 unicast link, for example, based on the V2X service type. During the unicast link establishment procedure, the UE can send its source layer-2 ID for the PC5 unicast link to the peer UE, for example, the UE whose destination ID related to it has been received from a higher layer. The pair of the source layer-2 ID and the destination layer-2 ID can uniquely identify the unicast link. The receiving UE can verify that the relevant destination ID belongs to it and can accept the unicast link establishment request from the source UE. During the PC5 unicast link establishment procedure, the PC5-RRC procedure in the access stratum can be executed for the purpose of establishing the UE sidelink context, as well as for the configuration of the AS stratum, function exchange, etc. PC5-RRC signaling can enable the exchange of UE functions between UEs pairs with a PC5 unicast link established and the configuration of the AS stratum such as sidelink radio bearer configuration.

[0019] NR sidelink communication can support one of three transmission modes (e.g., unicast transmission, groupcast transmission, broadcast transmission) for the pair of the source layer-2 ID and the destination layer-2 ID within the AS. The unicast transmission mode can be characterized by the support of one PC5-RRC connection between peer UEs regarding the pair, the transmission and reception of control information and user traffic between peer UEs during the sidelink, the support of sidelink HARQ feedback, the support of sidelink transmission power control, the support of RLC Acknowledged Mode (AM), and the detection of radio link failure regarding the PC5-RRC connection. Groupcast transmission is characterized by the transmission and reception of user traffic between UEs belonging to the group during the sidelink and the support of sidelink HARQ feedback. Broadcast transmission can be characterized by the transmission and reception of user traffic between UEs during the sidelink.

[0020] The source layer-2 ID, destination layer-2 ID, and PC5 link identifier can be used for NR sidelink communication. The source layer-2 ID can identify the sender of data in NR sidelink communication. The source layer-2 ID can be 24 bits in length and can be split into two-bit strings at the MAC layer. In this case, one-bit string is the LSB part (8 bits) of the source layer-2 ID and can be transmitted to the sender's physical layer. This can identify the source of the intended data in the sidelink control information and can be used for packet filtering at the receiver's physical layer. In this case, the second-bit string can be the MSB part (16 bits) of the source layer-2 ID and can be carried in the media access control (MAC) header. This can be used for packet filtering at the receiver's MAC layer. The destination layer-2 ID can identify the target of data in NR sidelink communication. In the case of NR sidelink communication, the destination layer-2 ID can be 24 bits in length and can be split into two-bit strings at the MAC layer. In this case, one-bit string is the LSB part (16 bits) of the destination layer-2 ID and can be transmitted to the sender's physical layer. This can identify the target of the intended data in the sidelink control information and can be used for packet filtering at the receiver's physical layer. In this case, the second-bit string can be the MSB part (8 bits ) and can be carried within the MAC header. This can be used for packet filtering at the receiver's MAC layer. The PC5 link identifier can uniquely identify the PC5 unicast link within the UE during the lifetime of the PC5 unicast link. The PC5 link identifier can be used to identify the PC5 unicast link for which its sidelink radio link failure (RLF) declaration has been made and the PC5-RRC connection has been released.

[0021] Figures 2A and 2B show examples of radio protocol stacks for the user plane and the control plane, respectively, according to some aspects of one or more exemplary embodiments of the present disclosure. As shown in FIG. 2A, the protocol stack of the user plane of the Uu interface (between UE 125 and gNB 115) includes Service Data Adaptation Protocol (SDAP) 201 and SDAP 211, Packet Data Convergence Protocol (PDCP) 202 and PDCP 212, Radio Link Control (RLC) 203 and RLC 213, layer 2 MAC 204 and MAC 214, and physical layer (PHY) 205 and PHY 215 layers (layer 1 is also referred to as L1).

[0022] PHY 205 and PHY 215 provide transport channel 244 to MAC 204 and MAC 214 sublayers. MAC 204 and MAC 214 sublayers provide logical channel 243 to RLC 203 and RLC 213 sublayers. RLC 203 and RLC 213 sublayers provide RLC channel 242 to PDCP 202 and PCP 212 sublayers. PDCP 202 and PDCP 212 sublayers provide radio bearer 241 to SDAP 201 and SDAP 211 sublayers. Radio bearers can be classified into two groups, namely data radio bearers (DRBs) for user plane data and signaling radio bearers (SRBs) for control plane data. SDAP 201 and SDAP 211 sublayers provide QoS flow 240 to 5GC.

[0023] The main services and functions of the MAC 204 or MAC 214 sublayer include the following: mapping between logical channels and transport channels, multiplexing / demultiplexing of MAC service data units (SDUs) belonging to one or different logical channels to / from transport blocks (TBs) transmitted to / from the physical layer on the transport channel, scheduling of information reporting, error correction through hybrid automatic repeat request (HARQ: one HARQ entity per cell in the case of carrier aggregation (CA)), priority handling between UEs by dynamic scheduling, priority handling between logical channels of one UE by logical channel prioritization (LCP), priority handling between overlapping resources of one UE, and padding. One MAC entity may support multiple numerologies, transmission timings, and cells. The mapping of priority determination within a logical channel controls which numerology, cell, and transmission timing the logical channel may use.

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

[0025] The RLC 203 or RLC 213 sublayer may support three transmission modes, namely Transparent Mode (TM), Un-acknowledged Mode (UM), and Acknowledged Mode (AM). The RLC configuration may conform to the logical channel without depending on the numerology and / or transmission time, and the automatic repeat request (ARQ) may operate at any of the numerology and / or transmission time by which the logical channel is configured.

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

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

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

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

[0030] As shown in FIG. 2B, the control plane protocol stack of the Uu interface (between UE 125 and gNB 115) includes the PHY layer (layer 1) as described above, and in addition to the MAC, RLC, and PDCP sublayers of layer 2, the RRC 206 sublayer and the RRC 216 sublayer. The main services and functions of the RRC 206 sublayer and the RRC 216 sublayer on the Uu interface include the following: broadcasting of system information related to AS and NAS, paging initiated by 5GC or NG-RAN, establishment, maintenance, and release of the RRC connection between the UE and NG-RAN (including addition, change, and release of carrier aggregation and addition, change, and release of dual connectivity within NR or between E-UTRA and NR), security functions including key management, establishment, configuration, maintenance, and release of SRBs and DRBs, mobility functions (handover and context transfer, UE cell selection and reselection and control of cell selection and reselection, including Inter-RAT mobility), QoS management functions, UE measurement result reporting and control of reporting, detection of radio link failure and recovery therefrom, NAS message transmission from NAS to UE / from UE to NAS. The NAS 207 and NAS 227 layers are control protocols that perform functions such as authentication, mobility management, and security control (terminated at the AMF on the network side).

[0031] The side-link specific services and functions of the RRC sublayer on the Uu interface include the following: setting of side-link resource allocation via system information or individual signaling, reporting of UE side-link information, setting and reporting of measurements related to the side link, reporting of UE assistance information for the SL traffic pattern.

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

[0033] The types of downlink transport channels include Broadcast Channel (BCH), Downlink Shared Channel (DL-SCH), and Paging Channel (PCH). BCH can be characterized by a fixed, pre-defined transport format and requirements broadcast over the entire cell coverage area either as a single message or by beamforming different BCH instances. DL-SCH can be characterized by support for HARQ, support for dynamic link adaptation by varying modulation, coding, and transmission power, the possibility of broadcasting over the entire cell, the possibility of using beamforming, support for both dynamic and semi-static resource allocation, and support for UE discontinuous reception (DRX) for UE power consumption reduction. DL-SCH can be characterized by support for HARQ, support for dynamic link adaptation by varying modulation, coding, and transmission power, the possibility of broadcasting over the entire cell, the possibility of using beamforming, support for both dynamic and semi-static resource allocation, and support for UE discontinuous reception (DRX:Discontinuous Recepti It can be characterized by the support of (on). PCH enables power consumption reduction of the UE by supporting UE discontinuous reception (DRX) (the DRX cycle is indicated to the UE by the network), either as a single message or by beamforming different BCH instances, requirements broadcast across the coverage area of the cell, and can be characterized by mapping to physical resources that can also be dynamically used for traffic / other control channels.

[0034] In the downlink, the following connections between logical channels and transport channels can exist: 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] The types of uplink transport channels include the uplink shared channel (UL-SCH) and the random access channel (RACH). UL-SCH can be characterized by support for dynamic link adaptation by varying the use of beamforming, transmission power, and possibly modulation and coding, support for HARQ, and support for both dynamic and semi-static resource allocation. RACH can be characterized by limited control information and a risk of collision.

[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] The types of sidelink transport channels include the following: sidelink broadcast channel (SL-BCH) and sidelink shared channel (SL-SCH). SL-BCH can be characterized by a pre-defined transport format. SL-SCH can be characterized by support for unicast transmission, groupcast transmission, and broadcast transmission, support for both UE automatic resource selection and scheduled resource allocation by NG-RAN, support for both dynamic and semi-static resource allocation when resources are allocated to the UE by NG-RAN, support for HARQ, and support for dynamic link adaptation by changing transmission power, modulation, and coding.

[0038] In sidelink, 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] Figures 4A, 4B, and 4C show exemplary mappings between transport channels and physical channels in the downlink, uplink, and sidelink, respectively, according to some aspects of one or more exemplary embodiments of the present disclosure. The physical channels in the downlink include Physical Downlink Shared Channel (PDSCH), Physical Downlink Control Channel (PDCCH), and Physical Broadcast Channel (PBCH). The PCH and DL-SCH transport channels are mapped to PDSCH. The BCH transport channel is mapped to PBCH. The transport channels are not mapped to PDCCH, but downlink control information (DCI) is transmitted via PDCCH.

[0040] The physical channels of the uplink include the Physical Uplink Shared Channel, 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 channel is not mapped to the PUCCH, but the uplink control information (UCI) is transmitted via the PUCCH.

[0041] The physical channels of sidelink include Physical Sidelink Shared Channel (PSSCH), Physical Sidelink Control Channel (PSCCH), Physical Sidelink Feedback Channel (PSFCH), and Physical Sidelink Broadcast Channel (PSBCH). The Physical Sidelink Control Channel (PSCCH) can indicate the resources used by the UE for PSSCH and other transmission parameters. The Physical Sidelink Shared Channel (PSSCH) can transmit the TBs of data itself, control information for HARQ procedures, CSI feedback triggers, etc. At least 6 OFDM symbols in a slot can be used for PSSCH transmission. The Physical Sidelink Feedback Channel (PSFCH) can carry HARQ feedback on the sidelink from the UE that is the intended receiver of the PSSCH transmission to the UE that performed the transmission. The PSFCH sequence can be transmitted on 1 PRB repeated in 2 OFDM symbols near the end of the sidelink resources in a slot. The SL-SCH transport channel can be mapped to the PSSCH. The SL-BCH can be mapped to the PSBCH. None of the transport channels are mapped to the PSFCH, but the sidelink feedback control information (SFCI) can be mapped to the PSFCH. None of the transport channels are mapped to the PSCCH, but the sidelink control information (SCI) can be mapped to the PSCCH.

[0042] Figures 5A, 5B, 5C, and 5D illustrate examples of radio protocol stacks for NR side-link communication according to some aspects of one or more exemplary embodiments of the present disclosure. The AS protocol stack for the user plane within the PC5 interface (i.e., for STCH) may consist of the SDAP, PDCP, RLC, and MAC sublayers and the physical layer. The protocol stack of the user plane is shown in Figure 5A. The AS protocol stack for the SBCCH within the PC5 interface may consist of the RRC, RLC, MAC sublayer, and the physical layer shown below in Figure 5B. To support the PC5-S protocol, as shown in Figure 5C, PC5-S is on top of the PDCP, RLC, and MAC sublayers and the physical layer in the control plane protocol stack of the SCCH for PC5-S. The AS protocol stack of the control plane of the SCCH for RRC within the PC5 interface consists of the RRC, PDCP, RLC, and MAC sublayers and the physical layer. The protocol stack of the control plane of the SCCH for RRC is shown in Figure 5D.

[0043] Sidelink Radio Bearers (SLRBs) can be classified into two groups, namely, Sidelink Data Radio Bearers (SL DRBs) for user plane data and Sidelink Signaling Radio Bearers (SL SRBs) for control plane data. Separate SLSRBs using different SCCHs can be configured for PC5-RRC and PC5-S signaling, respectively.

[0044] ​The MAC sublayer may provide the following services and functions on the PC5 interface: wireless resource selection, packet filtering, priority handling between uplink and sidelink transmissions for a UE, sidelink CSI reporting. Due to the constraints on the priority determination of logical channels within the MAC, only sidelink logical channels belonging to the same destination can be multiplexed into the MAC PDU for each unicast, groupcast, and broadcast transmission that can be associated with that destination. For packet filtering, an SL-SCH MAC header containing both parts of the source layer-2 ID and the destination layer-2 ID may be added to the MAC PDU. The logical channel identifier (LCID: Logical Channel Identifier) contained within the MAC subheader may uniquely identify the logical channel within the range of the combination of the source layer-2 ID and the destination layer-2 ID.

[0045] The services and functions of the RLC sublayer may be supported for the sidelink. Either RLC Unacknowledged Mode (UM) or Acknowledged Mode (AM) may be used for unicast transmissions, but only UM may be used for groupcast or broadcast transmissions. In the case of UM, only one-way transmission may be supported for groupcast and broadcast.

[0046] The services and functions of the PDCP sublayer of the Uu interface may be supported for the sidelink with some constraints. That is, out-of-order delivery may be supported only for unicast transmissions, and duplication is not supported on the PC5 interface.

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

[0048] The RRC sublayer may provide the following services and functions on the PC5 interface: transmission of PC5-RRC messages between peer UEs, maintenance and release of PC5-RRC connections between two UEs, detection of sidelink radio link failures related to the PC5-RRC connection based on indications from the MAC or RLC. The PC5-RRC connection may be a logical connection between two UEs for a pair of source and destination layer-2 IDs that may be considered to be established after the corresponding PC5 unicast link is established. There may be a one-to-one correspondence between the PC5-RRC connection and the PC5 unicast link. A UE may have multiple PC5-RRC connections with one or more UEs for different pairs of source and destination layer-2 IDs. Separate PC5-RRC procedures and messages may be used for a particular UE to transmit UE functions and sidelink configurations, including SL-DRB configurations, to a peer UE. Both peer UEs may exchange their respective UE functions and sidelink configurations using separate two-way procedures in both sidelink directions.

[0049] FIG. 6 shows exemplary physical signals for the downlink, uplink, and sidelink according to some aspects of one or more exemplary embodiments of the present disclosure. Demodulation reference signals (DM-RS) may be used on the downlink, uplink, and sidelink and may be used for channel estimation. The DM-RS is a UE-specific reference signal and is transmitted with the physical channel on the downlink, uplink , or can be transmitted via sidelink and 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 mitigate performance losses due to phase tracking and phase noise. The PT-RS can be mainly used to estimate and minimize the impact of the Common Phase Error (CPE) on the system performance. Due to the characteristics of phase noise, the PT-RS signal can be low density in the frequency domain and high density in the time domain. The PT-RS can be combined with the DM-RS and can also occur when the network is configured such that the PT-RS is present. A Positioning Reference Signal (PRS) can be used for positioning in the downlink using different positioning techniques. The PRS can be used to measure the delay of downlink transmission by correlating the received signal from the base station with a local replica in the receiver. A Channel State Information Reference Signal (CSI-RS) can be used in the downlink and sidelink. The CSI-RS can be used for channel state estimation, measurement of the Reference Signal Received Power (RSRP) for mobility and beam management, time / frequency tracking for modulation, and other purposes. The CSI-RS can be configured for individual UEs, but multiple users can share the same CSI-RS resource. The UE can identify CSI reports and transmit them to the base station in the uplink using the PUCCH or PUSCH. The CSI reports can be carried in the sidelink MAC CE. The Primary Synchronization Signal (PSS:Primary Information Reference Signal) can be used in the downlink and sidelink. The CSI-RS can be used for channel state estimation, measurement of the Reference Signal Received Power (RSRP) for mobility and beam management, time / frequency tracking for modulation, and other purposes. The CSI-RS can be configured for individual UEs, but multiple users can share the same CSI-RS resource. The UE can identify CSI reports and transmit them to the base station in the uplink using the PUCCH or PUSCH. The CSI reports can be carried in the sidelink MAC CE. The Primary Synchronization Signal (PSS:Primary The Primary Synchronization Signal (PSS) and the Secondary Synchronization Signal (SSS) can be used for radio frame synchronization. The PSS and SSS can be used for cell search procedures during initial attach or for mobility purposes. The Sounding Reference Signal (SRS) can be used for uplink channel estimation in the uplink. Similar to CSI-RS, the SRS can also serve as a QCL reference for other physical channels, and thus they can be configured and transmitted in a quasi-collocated relationship with the SRS. The SideLink PSS (S-PSS) and the SideLink SSS (S-SSS) can be used for side link synchronization in the side link.

[0050] Figure 7 shows examples of Radio Resource Control (RRC) states and transitions between different RRC states according to some aspects of one or more exemplary embodiments of the present disclosure. The UE can be in one of three RRC states, namely the RRC connected state 710, the RRC idle state 720, and the RRC inactive state 730. After power-up, the UE can be in the RRC idle state 720. The UE can use initial access to establish a connection with the network via the RRC connection establishment procedure to perform data transmission and / or send / receive voice calls. When the RRC connection is established, the UE can be in the RRC connected state 710. The UE can transition from the RRC idle state 720 to the RRC connected state 710 or from the RRC connected state 710 to the RRC idle state 720 using the RRC connection establishment / release procedure 740.

[0051] To reduce the signaling load and latency caused by the UE frequently transitioning from the RRC connected state 710 to the RRC idle state 720 when transmitting frequent small data, the RRC inactive state 730 can be used. In the RRC inactive state 730, the AS context can be stored by both the UE and the gNB. As a result, a fast state transition from the RRC inactive state 730 to the RRC connected state 710 can occur. The UE can transition from the RRC inactive state 730 to the RRC connected state 710, or from the RRC connected state 710 to the RRC inactive state 730, using the RRC connection resume / inactivation procedure 76 0. The UE can transition from the RRC inactive state 730 to the RRC idle state 720 using the RRC connection release procedure 750.

[0052] FIG. 8 shows an exemplary frame structure and physical resources according to some aspects of one or more exemplary embodiments of the present disclosure. Downlink or uplink or sidelink transmissions can be organized in a 10 ms time frame consisting of 10 1 ms subframes. Each subframe can consist of 1, 2, 4,... slots, and the number of slots per subframe can depend on the subcarrier spacing of the carrier where the transmission is performed. The slot duration can be 14 symbols of the normal cyclic prefix (CP) and 12 symbols of the extended CP, and the time can be scaled so that there is an integer number of slots within one subframe, depending on the subcarrier spacing used. FIG. 8 shows a resource grid in the time and frequency domains. Each element of the resource grid that includes one symbol in time and one subcarrier in frequency 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, packet transmission may be performed in a part of one slot, e.g., 2, 4, or 7 OFDM symbols, which may also be referred to as minislots, by scheduling not based on slots. Minislots can be used for low-latency applications such as URLLC and operation in unlicensed bands. In some embodiments, minislots can also be used for fast flexible scheduling of services (e.g., priority connection of URLLC in eMBB).

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

[0055] The UE can adjust the timing of its uplink transmission using uplink timing control procedures. Timing advance (TA) can be used to adjust the uplink frame timing with respect to the downlink frame timing. The gNB can specify the setting of the desired timing advance and provide it to the UE. The UE can use the provided TA to specify the uplink transmission timing with respect to the downlink reception timing observed for the UE.

[0056] In the RRC connected state, the gNB may play a role in maintaining the timing advance to keep L1 in a synchronized state. Uplinks with the same timing advance applied and serving cells with the same timing reference cell are grouped into a timing advance group (TAG). A TAG may include at least one serving cell for which the uplink is configured. The mapping of a serving cell to a TAG may be configured by RRC. In the case of the primary TAG, the UE may use the PCell as the timing cell, but in certain cases, the SCell may also be used as the timing reference cell, with the exception of shared spectrum channel access. In the secondary TAG, the UE may use any of the activated SCells of this TAG as the timing reference cell and, if not necessary, it cannot be changed.

[0057] The timing advance update may be signaled by the gNB to the UE via a MAC CE command. Such a command may restart the timer for each TAG, which may indicate whether L1 can be synchronized. That is, if the timer is running, L1 may be considered synchronized; otherwise, L1 may be considered not synchronized (in this case, uplink transmission may only be performed on the PRACH).

[0058] A UE having one timing advance capability related to CA may receive and / or transmit simultaneously on multiple CCs corresponding to multiple serving cells (the multiple serving cells are grouped into one TAG) sharing the same timing advance. A UE having multiple timing advance capabilities related to CA may receive and / or transmit simultaneously on multiple CCs corresponding to multiple serving cells (the multiple serving cells are grouped into multiple TAGs) having different timing advances. The NG-RAN may ensure that each TAG includes at least one serving cell. A UE not supporting CA may receive on one CC corresponding to only one serving cell (one serving cell within one TAG) and may transmit on one CC.

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

[0060] In a dual connectivity scenario, the UE may be composed of a master cell group (MCG) for communication with the master base station, a secondary cell group (SCG) for communication with the secondary base station, and multiple cells including two MAC entities, namely, one MAC entity for the MCG for communication with the master base station and one MAC entity for the SCG for communication with the secondary base station.

[0061] Figure 10 shows the configuration and switching of an exemplary bandwidth part according to some aspects of one or more exemplary embodiments of the present disclosure. A UE may be configured to have one or more bandwidth parts (BWPs) 1010 on a certain component carrier. In some examples, among the one or more bandwidth parts, one may be active at a time. The active bandwidth part may define the operating bandwidth of the UE within the operating bandwidth of the cell. At initial access, an initial bandwidth part 1020 specified from system information may be used until the configuration of the UE in the cell is received. For example, through bandwidth adaptation (BA) such as BWP switching 1040, the reception and transmission of the UE may be adjusted without being as large as the bandwidth of the cell. For example, the width may be instructed to change (e.g., to shrink during low activity periods to save power), the position within the frequency domain may be moved (e.g., to increase scheduling flexibility), and the subcarrier spacing may be instructed to change (e.g., to enable different services). The first active BWP 1020 may be the active BWP at the time of RRC (re)configuration for the PCell or at the activation of the SCell.

[0062] For each downlink BWP or uplink BWP in a set of downlink BWPs or uplink BWPs, the following configuration parameters may be provided to the UE : subcarrier spacing (SCS), cyclic prefix, number of common RBs and consecutive RBs, index within the set of downlink BWPs or uplink BWPs by each BWP-Id, BWP-common parameter set, and BWP-individual parameter set. A BWP may be associated with OFDM numerology according to the subcarrier spacing and cyclic prefix set for that BWP. For a certain serving cell, the UE may be provided by the default downlink BWP among the configured downlink BWPs. If no default downlink BWP is provided to the UE, the default downlink BWP may be the initial downlink BWP.

[0063] The downlink BWP may be associated with a BWP inactivity timer. When the BWP inactivity timer associated with the active downlink BWP expires and the default downlink BWP is configured, the UE may perform a BWP switch to the default BWP. When the BWP inactivity timer associated with the active downlink BWP expires and the default downlink BWP is not configured, the UE may perform a BWP switch to the initial downlink BWP.

[0064] FIG. 11 shows exemplary four-step collision-type and non-collision-type random access processes according to some aspects of one or more exemplary embodiments of the present disclosure. FIG. 12 shows exemplary two-step collision-type and non-collision-type random access processes according to some aspects of one or more exemplary embodiments of the present disclosure. The random access procedure may be triggered by various events, which may be, for example, initial access from the RRC idle state, RRC connection re-establishment procedure, arrival of downlink or uplink data during the RRC connected state when the uplink synchronization state is "asynchronous", arrival of uplink data during the RRC connected state when PUCCH resources are not available for a scheduling request (SR), SR failure, request by RRC during synchronization reconfiguration (e.g., handover), transition from the RRC inactive state, to establish time alignment for a secondary TAG, request for other system information (SI), beam failure recovery (BFR), continuous uplink listen-before-talk (LBT) failure at the PCell.

[0065] Two types of random access (RA) procedures, namely, a four-step RA type using MSGA and a two-step RA type using MSGA, may be supported. Both types of RA procedures may support collision-based random access (CBRA) and contention-free random access (CFRA), as shown in FIGS. 11 and 12.

[0066] When starting a random access procedure, the UE may select the type of random access based on the network configuration. If the CFRA resource is not configured, the UE may use the RSRP threshold to select between the two-step RA type and the step RA type. If the CFRA resource for the four-step RA type is configured, the UE may perform random access using the four-step RA type. If the CFRA resource for the two-step RA type is configured, the UE may perform random access using the two-step RA type.

[0067] The MSG1 of the four-step RA type may consist of the preamble of the PRACH. After transmitting MSG1, the UE may monitor the response from the network within the configured window. In the case of CFRA, an individual preamble for MSG1 transmission may be assigned by the network, and upon receiving a random access response (RAR) from the network, the UE may complete the random access procedure as shown in Figure 11. In the case of CBRA, upon receiving a random access response, the UE may transmit MSG3 using the uplink grant scheduled in the random access response and may monitor collision resolution as shown in Figure 11. If collision resolution fails after the (re)transmission of MSG3, the UE may return to MSG1 transmission. SG1 transmission.

[0068] The two-step RA type MSGA may include the preamble of the PRACH and the payload of the PUSCH. After transmitting the MSGA, the UE may monitor for a response from the network within a configured window. In the case of CFRA, individual preamble and PUSCH resources may be configured for MSGA transmission, and upon receiving a network response, the UE may complete the random access procedure as shown in FIG. 12. In the case of CBRA, if collision resolution is successful upon receiving a network response, the UE may complete the random access procedure shown in FIG. 12, but if a fallback indication is received within MSGB, the UE may use the uplink grant scheduled in the fallback indication to perform the transmission of MSG3 and may monitor for collision resolution. If collision resolution is not successful after the (re)transmission of MSG3, the UE may return to MSGA transmission.

[0069] FIG. 13 shows an exemplary time and frequency structure of a synchronization signal and a physical broadcast channel (PBCH) block (SSB) according to some aspects of one or more exemplary embodiments of the present disclosure. The SS / PBCH block (SSB) may consist of a primary and a secondary synchronization signal (PSS, SSS), each occupying one symbol and 127 subcarriers (e.g., subcarrier numbers 56 to 182 in FIG. 13), and a PBCH over three OFDM symbols and 240 subcarriers. As shown in FIG. 13, for the SSS, one symbol leaves the central unused portion. The possible time positions of the SSBs within a half-frame may be determined by the subcarrier spacing, and the period of the half-frame in which the SSBs are transmitted may be set by the network. During a half-frame, different SSBs may be transmitted in different spatial directions (i.e., using different beams, covering the entire cell coverage area).

[0070] The PBCH can be used to carry the Master Information Block (MIB) that the UE uses 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 necessary to obtain System Information Block 1 (SIB1), more specifically, the information necessary to monitor the PDCCH to schedule the PDSCH that carries SIB1. In addition, the MIB can indicate Cell Barred status information. The MIB and SIB1 can be collectively referred to as 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 SI. Other SI can be broadcast periodically on the DL-SCH, or broadcast on demand on the DL-SCH (e.g., in response to requests from UEs in the RRC idle state, RRC inactive state, or RRC connected state), or sent individually to UEs in the RRC connected state on the DL-SCH (e.g., if set by the network, in response to requests from UEs in the RRC connected state, or if the UE has an active BWP and no common search space is set).

[0071] Figure 14 shows an exemplary SSB burst transmission according to some aspects of one or more exemplary embodiments of the present disclosure. The SSB burst can include N SSBs, and each SSB of the N SSBs can correspond to a beam. The SSB burst can be transmitted according to a periodicity (e.g., SSB burst period). During a contention-based random access process, the UE can perform a random access resource selection process, where the UE first selects an SSB and then selects an RA preamble. The UE can select an SSB with an RSRP higher than a set threshold. In some embodiments, the UE can select any SSB if no SSB with an RSRP higher than the set threshold is available. The set of random access preambles The SSB can be associated with the PUCCH. After selecting the SSB, the UE can obtain a certain random access preamble from the set of random access preambles associated with the SSB, and can start the random access process by transmitting the selected random access preamble.

[0072] In some embodiments, a certain beam among the N beams can be associated with the CSI-RS resource. The UE can measure the CSI-RS resource and select the CSI-RS with an RSRP higher than the set threshold. The UE can select the random access preamble corresponding to the selected CSI-RS, transmit the selected random access preamble, and start the random access process. If there is no random access preamble associated with the selected CSI-RS, the UE can select the random access preamble corresponding to the SSB that is in a quasi-collocation relationship with the selected CSI-RS.

[0073] In some embodiments, based on the measurement of the CSI-RS resource by the UE and the CSI report by the UE, the base station can identify the transmission configuration indication (TCI) state, can indicate the TCI state to the UE, and the UE can use the indicated TCI state for receiving downlink control information (e.g., via PDCCH) or data (e.g., via PDSCH). The UE can use the indicated TCI state to use the appropriate beam for receiving data or control information. The indication of the TCI state can be using the RRC configuration, or a combination of RRC signaling and dynamic signaling (e.g., based on the value of a field in the downlink control information that schedules the downlink transmission via a MAC control element (MAC CE) and / or). The TCI state can indicate the quasi-collocation (QCL) relationship between the downlink reference signal such as CSI-RS and the DM-RS associated with the downlink control or data channel (e.g., PDCCH or PDSCH respectively).

[0074] In some embodiments, the UE may use physical downlink shared channel (PDSCH) configuration parameters to be configured with a list of TCI states up to M, and may decode the PDSCH according to the PDCCH detected by the DCI intended for the UE and a serving cell, where M may depend on the UE's capabilities. Each TCI-state may include parameters for configuring a quasi-co-location (QCL) relationship between one or two downlink reference signals and the DM-RS ports of the PDSCH, the DM-RS ports of the PDCCH, or the CSI-RS ports of the CSI-RS resources. The quasi-co-location relationship may be configured by one or more RRC parameters. The type of quasi-co-location corresponding to each DL RS may take one of the following values: 'QCL-TypeA': {Doppler shift, Doppler spread, average delay, delay spread}, 'QCL-TypeB': {Doppler shift, Doppler spread}, 'QCL-TypeC': {Doppler shift, average delay}, 'QCL-TypeD': {Spatial Rx parameters}. The UE may receive an activation command (e.g., MAC CE) used to map the TCI state to a code point in the DCI field.

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

[0076] As shown in FIG. 15, the antenna 1510 may be used for transmitting or receiving electromagnetic signals. The antenna 1510 may include one or more antenna elements, thereby enabling various 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, a massive MIMO configuration using dozens or hundreds of antenna elements may be realized in the antenna 1510. The antenna 1510 may use other multi-antenna technologies such as beamforming. In some examples, and depending on the capabilities of the UE 1500 and the type of the UE 1500 (e.g., low-complexity UE), the UE 1500 may support only a single antenna.

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

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

[0079] Processor 1540 may include a hardware device having processing capabilities (e.g., a general-purpose processor, DSP, CPU, microcontroller, ASIC, FPGA, programmable logic device, discrete gate or transistor logic components, discrete hardware components, 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 incorporated within processor 1540. Processor 1540 may be configured to execute computer-readable instructions stored in a memory (e.g., memory 1530) to cause various functions to be performed by UE 1500 or base station 1505.

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

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

[0082] In some examples, for the multicast / broadcast data channel, the following scheduling information can be provided on the multicast / broadcast control channel: the scheduling cycle of the multicast / broadcast data channel, the reception period of the multicast / broadcast data channel (e.g., the period during which the UE waits for the reception of PDCCHs after returning from DRX), the multicast / broadcast data channel inactivity timer (e.g., the period during which the UE waits for the decoding of the PDCCH indicating the DL-SCH to which this multicast / broadcast data channel is mapped to succeed again after the last successful decoding of the PDCCH, and if it fails, re-enters DRX).

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

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

[0085] In some examples, the UE may inform the RAN that the UE is receiving or is interested in receiving MBS services via an MBS radio bearer, and if so, use procedures to inform the 5G RAN about the priority of MBS-to-unicast reception or reception of MBS services. The UE may send a message (e.g., an MBS interest indication message) to the RAN to inform the RAN that the UE is receiving / is interested in receiving MBS services or is no longer receiving / is no longer interested in receiving them. The UE may send that message based on receiving one or more messages from the network (e.g., an SIB message or a unicast RRC message) indicating one or more MBS service area identifiers of the current and / or adjacent carrier frequencies. and send it based on receiving (e.g., an SIB message or a unicast RRC message).

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

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

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

[0089] In some examples, changes to MCCH information may be made in a specific radio frame / subframe / slot and / or a change period may be used. For example, within a certain change period, the same MCCH information may be transmitted multiple times according to the provisions by its scheduling (which is based on the repetition period). The boundary of the change period may be defined by the SFN value where SFN mod m = 0, where m is the number of radio frames including the change period. The change period may be set by SIB or by RRC signaling.

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

[0091] In one example, the system information block (SIB) may include information necessary to obtain transmissions related to the control information of the MBS. The information may include at least one of one or more discontinuous reception (DRX) parameters for monitoring the scheduling information of transmissions related to the control information of the MBS, the scheduling period and offset of the scheduling information of transmissions related to the control information of the MBS, the change period for the change of the content of the communication related to the control information of the MBS, the repetition information for the repetition of transmissions related to the control information of the MBS, and the like.

[0092] In one example, the information element (IE) may provide a list of ongoing MBS sessions transmitted via one or more bearers for each MBS session, for example, one or more related RNTIs (e.g., G-RNTI, and other names may also be used), and configuration parameters indicating scheduling information. The configuration parameters may include at least one of one or more timer values of discontinuous reception (DR X) (e.g., inactivity timer or On Duration timer), an RNTI for scrambling the scheduling and transmission of the multicast / broadcast traffic channel (e.g., MTCH, and other names may also be used), one or more power management control parameters, one or more scheduling periodicities and / or offset values for one or more MBS traffic channels, information regarding a list of neighboring cells, and the like.

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

[0094] In some examples, the information element (IE: information element) MeasIdleConfig may be used to convey information to the UE regarding measurements required to be made during RRC_IDLE or RRC_INACTIVE. Exemplary parameters of the MeasIdleConfig IE may include the following parameters. Other parameters for measurements regarding the MBS service / session while in the RRC IDLE or RRC INACTIVE state may be used in addition to, or instead of, one or more of the following parameters. These parameters include:

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

[0096] In some examples, the SIB (e.g., SIB11) can include information regarding idle / non-active measurements. The parameter / IE measIdleConfigSIB can indicate the measurement configuration that the UE stores and uses during RRC_IDLE or RRC_INACTIVE.

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

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

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

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

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

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

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

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

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

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

[0107] The suspendConfig field may provide the UE with the configuration necessary for the RRC_INACTIVE state and may indicate, for example, the full I-RNTI, short I-RNTI, ran-NotofocationAreaInfo, ran-PagingCycle, the value of the timer that triggers periodic RNA updates, etc.

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

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

[0110] In some examples, the ResumeCause field may indicate one of the following, or may indicate other parameters associated with MBS services 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] When receiving a resume request from the UE, the network may send an RRC Resume (DCCH) to resume the suspended RRC connection. The UE may confirm the success of the completion of the RRC connection resume procedure by sending an RRC Resume Complete (DCCH) message.

[0112] In some examples, in the RRC_INACTIVE state, the UE may remain CM-CONNECTED and may move within the area configured by the NG-RAN (RAN notification area (RNA)) without notifying the NG-RAN. In this state, the gNB node that last provided the service may hold the UE context and the UE-related NG connection with the AMF and UPF that provide the service. When the gNB that last provided the service receives downlink data from the UPF or downlink UE-related signaling from the AMF, it pages in the cell corresponding to the RNA, and if the RNA includes the cells of the adjacent gNB(s), it may send Xn-AP RAN paging to the adjacent gNB(s).

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

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

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

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

[0117] In some examples, when the UE accesses a gNB other than the gNB that last provided service to it, the receiving gNB may trigger the Xn-AP Retrieve UE Context procedure to obtain the UE context from the gNB that last provided service to the UE. If the UE accesses a gNB other than the gNB that last provided service to it and the receiving gNB does not find a valid UE context, the receiving gNB may perform the establishment of a new RRC connection instead of resuming the previous RRC connection.

[0118] In some examples, a Multicast Broadcast Service (MBS) may 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). In exemplary solutions for service continuity and handover procedures, UE and service mobility of MBS services / sessions for UEs in the RRC inactive state or RRC idle state are not considered. It is necessary to maintain service continuity and mobility of MBS services for UEs in the RRC idle and RRC inactive states. According to an exemplary embodiment, service continuity and mobility of MBS services / sessions for UEs in the RRC idle and RRC inactive states are realized.

[0119] Considering the wide range of MBS services and the emphasis on power consumption reduction in 5G, it is also important to maximize the commonalities with the mobility in the connected state while maintaining MBS service continuity and mobility for idle and inactive UEs. In some examples, such mobility support for idle / inactive UEs is not required for all MBS services and is not supported in the same way for all UEs. In some examples, the level of mobility support for MBS services can be set per MBS service and / or per UE.

[0120] In some examples, for some MBS services, such as low duty cycle services, UEs can receive MBS data not only in the connected state but also in the idle / inactive state even when they move to other cells. This can be a QoS parameter, which can be set per service and / or per user.

[0121] In some examples, supporting service continuity along with mobility may be possible for UEs in the RRC inactive state only, or for UEs in the RRC idle state only, or for UEs in both the RRC inactive state and the RRC idle state. In some examples, support for service continuity (SC) of MBS services in general, and for UEs in the idle / inactive state in particular, may be QoS parameters that can be set per service and / or per UE.

[0122] In some examples, for MBS with SC options, the geographical area where such services may be expected by the UE can be set by application layer signaling. UEs can determine whether the MBS service it targets is provided in an adjacent cell using its geolocation or based on configuration information received from the service / selected (target) cell.

[0123] An exemplary process for MBS service continuity in the RRC inactive state or the RRC idle state is shown in FIG. 17. In some examples, measurements and trigger events can be set for the UE, and the UE can indicate to the RAN the need for MBS service continuity when the UE moves to a target cell while in the RRC idle or RRC inactive state.

[0124] In some examples, UEs in the RRC inactive / idle state can have MBS service continuity MBS - SC measurements and triggers set to initiate the MBS service continuity process. In some examples, the types of measurement thresholds and / or events can be specific to MBS service continuity. In some examples, the types of thresholds and / or events can have different values, which are set for cell (re)selection in the RRC idle or RRC inactive state.

[0125]

[0126] ​ Exemplary options for MBS service continuity in the RRC inactive state or RRC idle state are shown in FIG. 18. In some examples, when the UE determines that the RAN needs to handle its MBS service continuity, it may initiate a procedure, which may or may not require the UE to return to the connected state. In some examples (e.g., the options in FIG. 18), for a UE in the RRC inactive / idle state, based on checking the MBS SC trigger, the UE may return to the RRC connected state and use the connection state mobility procedure for MBS H0 with the target cell. In some examples (e.g., the options in FIG. 18), a UE in the RRC inactive state may, based on checking the MBS SC trigger, send an update to the RAN, for example, based on the RAN Notification Area (RNA) update RNA Update in the RRCResumeRequest, or may perform other procedures indicating that it is migrating to the target cell while remaining in the RRC inactive state. In some examples, through this process, such an MBS context of the UE as part of the UE's RAN context may be shared with the target cell without the UE returning to the connected state. If MBS settings, such as BWP, subframe, slot time / format, etc., are different within the target cell, such information may be included in the RRC signaling returned to the UE, for example, as part of a suspension indication message. In some examples (e.g., option c in FIG. 18), a UE in the RRC inactive or RRC idle state may, based on checking the MBS SC trigger, send an update using RACH-based signaling, indicating to the network that the UE is leaving the source cell and moving towards the target and about the MBS services the UE is receiving. Such signaling may reuse message A of the two-step RACH or message 3 of the four-step RACH procedure. Similar to option b, based on receiving this RACH signal, the RAN may send an RRC message, for example, message B of the two-step RACH process or four-step It is possible to send a message of the PRACH process to the UE, which includes information necessary for the UE to identify MBS services within the target cell. The two-step RACH procedure can reduce signaling more efficiently. The message A from the UE may include several identifiers for the UE and the target MBS service, and the message B from the RAN may include the MBS configuration of the service selected by the UE within the target cell.

[0127] In some examples, the UE may initiate signaling with the source cell, and the source cell may request the MBS configuration of the target cell. The source cell may receive the MBS configuration of the target cell and send the MBS configuration of the target cell to the UE. In some examples, the UE may first initiate signaling with the target cell, and the target cell may obtain the MBS context of the UE from the source cell. The UE may continue to receive its MBS data during the handover.

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

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

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

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

[0132] A preconfigured / group of configured random access preambles can be associated with an MBS service / session. The UE may send a first message based on a random access process, which indicates a request for MBS configuration parameters associated with one or more MBS services via a target cell. For example, the UE may send the first message based on Msg3 of a 4-step random access process or MsgA of a 2-step random access process. The first message may include one or more service identifiers (e.g., Mobile Group Identifiers (TMGIs)), which indicate MBS services received from the cell on which the UE is currently camped or MBS services that the UE is interested in receiving from the target cell (e.g., MBS services for which service continuity is required). In some examples, the Quality of Service (QoS) of a service associated with an MBS service / session (e.g., an MBS bearer) may indicate whether service continuity (e.g., service continuity in idle and / or inactive states) is required for the MBS service / session, and the UE and / or gNB may consider the QoS requirements of the MBS bearer in the transmission of the first message or admission control by the target cell. The first message may include one or more fields, and one or more values of the one or more fields are associated with a specified service continuity trigger and / or the need for service continuity for one or more MBS services. For example, the one or more fields may include a cause field indicating the cause of the first message transmission. For example, the first message may be sent during other procedures and / or for other reasons, and the value of the cause field may indicate the cause of the first message transmission. For example, if the UE is in the RRC inactive state, the first message may be an RRC resume request message, and the value of the cause field (e.g., resume cause field) indicates that the cause of the first message transmission is for service continuity associated with one or more MBS services.The value of the cause field may indicate that the cause of the first message transmission is for service continuity associated with one or more MBS services while the RRC is in the inactive state.

[0133] In response to transmitting the first message, the UE may receive information necessary to receive MBS configuration parameters and / or data associated with the MBS service using the target cell. In the 4-step random access process, receiving the information necessary to receive MBS configuration parameters and / or data associated with the MBS service using the target cell may be Msg4. In the 2-step random access process, receiving the information necessary to receive MBS configuration parameters and / or data associated with the MBS service using the target cell may be MsgB. In some examples, the UE may receive the information necessary to receive the received MBS configuration parameters and / or data associated with the MBS service from the cell on which the UE is currently camping. In some examples, the UE may receive the information necessary to receive the received MBS configuration parameters and / or data associated with the MBS service from the target cell.

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

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

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

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

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

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

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

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

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

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

[0144] In some embodiments, the first message may include one or more service identifiers associated with one or more MBS services provided by the current cell on which the UE is camped. In some embodiments, the one or more MBS configuration parameters may include one or more first service identifiers of the one or more MBS service identifiers, and 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 associated with a certain MBS service among the one or more MBS services may indicate the service continuity requirement level for that MBS bearer.

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

[0147] In some embodiments, transmitting the first message may be via message 3 of the 4-step random access process. In some embodiments, receiving the one or more MBS configuration parameters may be via message 4 of the 4-step random access process.

[0148] In some embodiments, transmitting the first message may be via message A of the 2-step random access process. In some embodiments, receiving the one or more MBS configuration parameters may be via message B of the 2-step random access process.

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

[0150] The exemplary blocks and modules described herein with respect to the various exemplary embodiments of the present disclosure may be implemented or executed using a general-purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. Examples of general-purpose processors include, but are not limited to, microprocessors, any conventional processor, controller, microcontroller, or state machine. In some examples, the processor may be implemented using a combination of devices (e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors using a DSP core, or any other such configuration).

[0151] The functions described in this disclosure may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. Instructions or code may be stored on or transmitted across a computer-readable medium for execution of these functions. Other examples of implementation of the functions disclosed herein are also included within the scope of the present disclosure. Execution of the functions may be via elements installed in physically the same location or (e.g., at various locations) distributed elements, including where each part of the function is distributed so as to be executed at a different physical location.

[0152] Computer-readable media includes, but is not limited to, non-transitory computer storage media. Non-transitory storage media can be accessed by a general purpose or special purpose computer. Examples of non-transitory storage media include, but are not limited to, random access memory (RAM), read-only memory (ROM), electrically erasable programmable ROM (EEPROM), flash memory, compact disc (CD) ROM or other optical disk storage, magnetic disk storage, or other magnetic storage devices, etc. 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 by a general purpose or special purpose processor. In some examples, software / program code can be transmitted from a remote resource (e.g., a website, server, etc.) via 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 included within the definition of the medium. Combinations of the above examples are also included within the scope of computer-readable media. In such examples, coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included within the definition of the medium. Combinations of the above examples are also included within the scope of computer-readable media.

[0153] As used in this disclosure, the use of the term "or" in a listing of items indicates an inclusive listing. The listing of items may be used in combination with phrases such as "at least one of" or "one or more of". For example, a listing of at least one of A, B, or C includes A or B or C or AB (i.e., A and B) or AC or BC or ABC (i.e., A, B, and C). Also, as used in this disclosure, when a listing of conditions is used in combination with the phrase "based on", it is to be understood that the result is "based at least in part on" that group of conditions, rather than "based only on" that group of conditions. For example, a result described as "based on condition A" may also be based on both condition A and condition B, and this does not depart from the scope of this disclosure.

[0154] In this specification, the terms "comprise", "include", or "contain" are used interchangeably and may have the same meaning, and are to be construed as inclusive and open-ended. The term "comprise", "include", or "contain" when used in combination with a listing of elements may indicate that all of the elements listed in the listing are present, but that other elements not in that listing may also be present. For example, if A comprises B and C, then both {B, C} and {B, C, D} are within the scope of A.

[0155] This disclosure describes exemplary configurations in relation to the accompanying drawings, but these do not necessarily represent all examples that can be implemented 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 "an example, instance, or illustration". By reading this disclosure, including the description of the embodiments and the drawings, those skilled in the art will understand that the technology disclosed in this application can be implemented using alternative embodiments. Those skilled in the art will also understand that they can combine these embodiments or specific features of the embodiments described herein to arrive at another embodiment for practicing the technology described in this disclosure. Therefore, this disclosure is not limited to the examples and designs described herein, but is to the broadest scope that does not conflict with the principles and novel features disclosed in this application.

[0156] Item 1. A method for maintaining service continuity is: a step of receiving, by a user equipment (UE) in a certain radio resource control (RRC) state, a broadcast message including measurement setting parameters, where the RRC state corresponds to at least one of the RRC inactive state and the RRC idle state, and a step of identifying a service continuity trigger for one or more multicast broadcast service (MBS) services based on the measurement setting parameters, and a step of starting a random access process (RAP) based on the identified service continuity trigger, where starting the RAP includes transmitting a first message indicating a request for MBS setting parameters associated with one or more MBS services, and a step of receiving one or more MBS setting parameters in response to transmitting the first message, and a step of receiving data associated with one or more MBS services via a target cell while remaining in its RRC state based on the MBS setting parameters, and includes.

[0157] Item 2. In the method of Item 1, the broadcast message is a System Information Block (SIB) message.

[0158] Item 3. In the method of Item 1, the measurement configuration parameters include at least one of one or more threshold values, a carrier frequency for measurement, a list of frequency bands, measurement parameters of a beam relationship, a measurement duration, a list of measurement cells, and the number of Synchronization Signal Blocks (SSBs) for cell measurement derivation.

[0159] Item 4. In the method of Item 1, the step of identifying a service continuity trigger includes measuring one or more Synchronization Signal Blocks (SSBs) and comparing the received signal strength of the one or more SSBs with one or more threshold values.

[0160] Item 5. In the method of Item 1, the first message includes a cause field, which contains information indicating that the first message is transmitted in response to a service continuity trigger and the first message is transmitted to request Multi-Cast Broadcast Service (MBS) configuration parameters and has information including at least one of the above.

[0161] Item 6. In the method of Item 1, the Radio Resource Control (RRC) corresponds to an inactive state, the first message is an RRC resume request message, and the values of one or more fields in the RRC resume request message indicate a request for one or more Multi-Cast Broadcast Service (MBS) configuration parameters while remaining in the RRC inactive state.

[0162] Item 7. In the method of Item 6, the one or more fields include a resume cause field.

[0163] Item 8. In the method of Item 6, the step of receiving one or more multicast broadcast service (MBS) configuration parameters includes receiving a radio resource control (RRC) rejection message corresponding to an instruction to remain in the RRC inactive state.

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

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

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

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

[0168] Item 13. In the method of Item 1, for a certain MBS among the one or more MBS services the quality of service (QoS) of the service associated with the multicast broadcast service (MBS) bearer associated with the MBS service indicates the level of the service continuity requirement for the MBS bearer.

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

[0170] Item 15. In the method of Item 1, the step of transmitting the first message includes transmitting the first message via a 4-step random access process of Message 3.

[0171] Item 16. In the method of Item 15, the step of receiving one or more multicast broadcast service (MBS) configuration parameters includes receiving the MBS configuration parameters via a 4-step random access process of Message 4.

[0172] Item 17. In the method of Item 1, the step of transmitting the first message includes transmitting the first message via a 2-step random access process of Message A.

[0173] Item 18. In the method of Item 17, receiving one or more multicast broadcast service (MBS) configuration parameters includes receiving the MBS configuration parameters via Message B within the 2-step random access process.

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

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

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

[0177] Item 22. An apparatus used in wireless communication comprises: an antenna used for transmitting electromagnetic signals, and a memory holding computer-readable code, and a processor that executes the computer-readable code to cause the apparatus to: receive, by a user equipment (UE) in a certain radio resource control (RRC) state, a broadcast message including measurement setting parameters, where the RRC state corresponds to at least one of an RRC inactive state and an RRC idle state, identify a service continuity trigger for one or more multicast broadcast services (MBS) based on the measurement setting parameters, initiate a random access process (RAP) based on the identified service continuity trigger, where initiating the RAP includes transmitting a first message indicating a request for MBS setting parameters associated with one or more MBS services, receive one or more MBS setting parameters in response to transmitting the first message, receive data associated with one or more MBS services via a target cell while remaining in the RRC state based on the MBS setting parameters a processor, and including.

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

[0179] Item 24. In the apparatus of Item 22, the measurement setting parameters include at least one of one or more threshold values, a carrier frequency for measurement, a list of frequency bands, measurement parameters of beam relationships, a measurement duration, a list of measurement cells, and the number of synchronization signal blocks (SSBs) for cell measurement derivation.

[0180] Item 24. In the apparatus of Item 22, specifying a service continuity trigger includes measuring one or more synchronization signal blocks (SSBs) and comparing the received signal strength of one or more SSBs with one or more threshold values.

[0181] Item 25. In the apparatus of Item 22, the first message includes information indicating at least one of that the first message is transmitted in response to a service continuity trigger and that the first message is transmitted to request multi-cast broadcast service (MBS) setting parameters.

[0182] Item 26. In the apparatus of Item 22, the radio resource control (RRC) corresponds to the inactive state, the first message is an RRC resume request message, and the value of one or more fields in the RRC resume request message indicates a request for one or more multi-cast broadcast service (MBS) setting parameters while remaining in the RRC inactive state.

[0183] Item 27. In the apparatus of Item 26, the one or more fields include a resume cause field.

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

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

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

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

[0188] Item 32. In the apparatus of Item 31, one or more multicast broadcast service (MBS) configuration parameters indicate one or more first service identifiers among the one or more MBS service identifiers, and the one or more first service identifiers are associated with a target cell.

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

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

[0191] Item 35. In the apparatus of Item 22, the apparatus transmits a first message according to the random access process.

[0192] Item 36. In the apparatus of item 22, 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, and the RRC release message includes one or more Multicast Broadcast Service (MBS) service continuity parameters. The apparatus

[0193] Item 37. In the apparatus of item 36, the Radio Resource Control (RRC) release message indicates a transition to the RRC inactive state and includes a suspend config information element including service continuity parameters of one or more Multicast Broadcast Service (MBS) services.

[0194] Item 38. A method for maintaining service continuity is as follows: transmitting a broadcast message including measurement setting parameters to a user equipment (UE) in a certain Radio Resource Control (RRC) state, where the RRC state of the UE corresponds to at least one of the RRC inactive state and the RRC idle state; receiving, from the UE, a first message indicating a request for MBS setting parameters associated with one or more MBS services; in response to transmitting the first message, transmitting one or more MBS setting parameters to the UE; transmitting data associated with one or more MBS services via a target cell while remaining in the RRC state based on the MBS setting parameters; and including.

[0195] Item 39. In the method of item 38, the broadcast message is a System Information Block (SIB) message.

[0196] Item 40. In the method of Item 38, the measurement setting parameters include at least one of one or more threshold values, a carrier frequency for measurement, a list of frequency bands, measurement parameters of a beam relationship, a measurement duration, a list of measurement cells, and the number of synchronization signal blocks (SSBs) for cell measurement derivation.

[0197] Item 41. In the method of Item 38, the first message includes a cause field, which has information including at least one indication that the first message is transmitted in response to a service continuity trigger and that the first message is transmitted to request multi - cast broadcast service (MBS) setting parameters. to have.

[0198] Item 42. In the method of Item 38, the radio resource control (RRC) corresponds to an inactive state, the first message is an RRC resume request message, and the value of one or more fields in the RRC resume request message indicates a request for one or more multi - cast broadcast service (MBS) setting parameters while remaining in the RRC inactive state.

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

[0200] Item 44. In the method of Item 38, the one or more multi - cast broadcast service (MBS) setting parameters include one or more first parameters for receiving control information.

[0201] Item 45. In the method of Item 38, the one or more multi - cast broadcast service (MBS) setting parameters include a bandwidth part identifier, a control resource set, and a numerology associated with the one or more MBS services.

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

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

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

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

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

[0207] Item 51. In the method of Item 38, it further includes the step of transmitting a radio resource control (RRC) release message indicating a transition to the RRC inactive state or the RRC idle state, and the RRC release message includes service continuity parameters of one or more multicast broadcast services (MBS).

[0208] Item 52. In the method of Item 51, the radio resource control (RRC) release message indicates a transition to the RRC inactive state and includes a suspend config information element including service continuity parameters of one or more multicast broadcast service (MBS).

[0209] Item 53. An apparatus used in wireless communication includes: an antenna used for transmitting electromagnetic signals, a memory holding computer-readable code, a processor that executes the computer-readable code to cause the apparatus to: receive, from a user equipment (UE) in a certain radio resource control (RRC) state, a broadcast message including measurement configuration parameters, where the RRC state of the UE corresponds to at least one of the RRC inactive state and the RRC idle state, receive, from the UE, a first message indicating a request for MBS configuration parameters associated with one or more MBS services, in response to transmitting the first message, transmit to the UE one or more MBS configuration parameters, based on the MBS configuration parameters, while remaining in its RRC state, transmit data associated with one or more MBS services via a target cell, and .

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

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

[0212] ​Item 56. In the apparatus of item 53, the first message includes a cause field having information including an indication that the first message is transmitted in response to a service continuity trigger and an indication that the first message is transmitted to request multicast broadcast service (MBS) configuration parameters, at least one of which is included.

[0213] Item 57. In the apparatus of item 53, the radio resource control (RRC) corresponds to an inactive state, the first message is an RRC resume request message, and the value of one or more fields in the RRC resume request message indicates a request for one or more multicast broadcast service (MBS) configuration parameters while remaining in the RRC inactive state.

[0214] Item 58. In the apparatus of item 42, the apparatus is further configured to transmit a radio resource control (RRC) rejection message corresponding to an instruction to remain in the RRC inactive state.

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

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

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

[0218] Item 62. In the apparatus of item 53, one or more multicast broadcast service (MBS) configuration parameters indicate one or more first service identifiers among one or more MBS service identifiers, and the one or more first service identifiers are associated with a target cell.

[0219] Item 63. In the apparatus of item 53, the quality of service (QoS) of a service associated with a multicast broadcast service (MBS) bearer associated with a certain MBS service among one or more MBS services indicates the level of service continuity requirements for that MBS bearer.

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

[0221] Item 65. In the apparatus of item 53, the apparatus is further configured to transmit a first message according to the random access process.

[0222] Item 66. In the apparatus of item 53, 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, and the RRC release message includes one or more multicast broadcast service (MBS) service continuity parameters.

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

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

Claims

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

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

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

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

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

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

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

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

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

10. The first information is included in a system information block (SIB) message. The method according to claim 8.

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

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

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

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