System and method for configuring user equipment for multicast reception in wireless communication system

Abstract

Systems and methods for configuring UEs for multicast reception in a wireless network. Embodiments disclosed herein relate to a system (100) and method (400, 500, 600, 700, 800, 900, 1000) for configuring a user equipment (UE) (102) for new radio multicast and broadcast service (NR MBS) reception in a radio resource control (RRC) inactive state. The method (400, 500, 600, 700, 800, 900, 1000) includes configuring the UE to efficiently and seamlessly continue to receive one or more multicast service configurations for MBS multicast service reception when the UE transitions from an RRC connected state to an RRC inactive state. The method (400, 500, 600, 700, 800, 900, 1000) includes configuring the UE for MBS multicast service reception with one or more signaling processes. The method (400, 500, 600, 700, 800, 900, 1000) includes managing a multicast MRB configuration to receive a multicast service in an RRC inactive state.

Description

Technical Field

[0001] The present disclosure relates generally to wireless communication networks, and more particularly, to systems and methods for configuring a user equipment (UE) for New Radio Multicast and Broadcast Service (NR MBS) multicast service reception in a Radio Resource Control (RRC) inactive state. Background Art

[0002] The fifth generation (5G) mobile communication technology defines a wide frequency band so that high transmission rates and new services are possible, and can be realized not only in frequency bands below 6 gigahertz (GHz) such as 3.5 GHz, but also in frequency bands above 6 GHz including 28 GHz and 39 GHz called millimeter wave (mmWave) bands. In addition, it has been considered to realize 6G mobile communication technology (called super 5G system) in terahertz (THz) bands (such as 95 GHz to 3THz bands), realizing a transmission rate fifty times faster than 5G mobile communication technology and an ultra-low latency one-tenth of 5G mobile communication technology.

[0003] At the very beginning of the development of 5G mobile communication technology, in order to support services and meet performance requirements related to enhanced mobile broadband (eMBB), ultra-reliable and low-latency communications (URLLC), and massive machine type communications (mMTC), there has been ongoing standardization on technologies such as beamforming and massive multiple-input multiple-output (MIMO) for mitigating radio wave path loss and increasing radio wave transmission distance in millimeter waves, parameter sets (such as operating multiple subcarrier spacings) and dynamic operation of time slot formats to support efficient utilization of millimeter wave resources, initial access technology for supporting multi-beam transmission and broadband, definition and operation of bandwidth parts (BWPs), new channel coding methods (such as low-density parity-check (LDPC) codes for large-volume data transmission and polar codes for highly reliable transmission of control information), L2 preprocessing, and network slicing for providing dedicated networks dedicated to specific services.

[0004] In view of the services to be supported by 5G mobile communication technology, discussions on improvements and performance enhancements of initial 5G mobile communication technology are ongoing, and there is already physical layer standardization on technologies such as Vehicle-To-Everything (V2X) for assisting driving determination of autonomous vehicles based on information about the position and status of vehicles transmitted by the vehicles and for enhancing user convenience, New Radio Unlicensed (NR-U) for system operation intended to comply with various regulation-related requirements in unlicensed bands, NR UE power saving, Non-Terrestrial Network (NTN) as UE-satellite direct communication for providing coverage in areas where communication with terrestrial networks is unavailable, and positioning.

[0005] In terms of air interface architecture / protocol, standardization is being conducted on various technologies such as the Industrial Internet of Things (IIoT) for supporting new services through interworking and integration with other industries, Integrated Access and Backhaul (IAB) for providing nodes for network service area expansion by supporting wireless backhaul links and access links in an integrated manner, mobility enhancement including conditional handover and dual active protocol stack (DAPS) handover, and two-step random access channel (NR's 2-step RACH) for simplifying the random access procedure. In terms of system architecture / service, standardization is also being conducted on various technologies such as 5G service-based architecture or service-based interface for combining Network Functions Virtualization (NFV) and Software-Defined Networking (SDN) technologies, and Mobile Edge Computing (MEC) for receiving services based on UE location.

[0006] As 5G mobile communication systems are commercialized, the number of connected devices, which has been growing exponentially, will be connected to the communication network, and therefore, it is expected that enhanced functions and performance of 5G mobile communication systems and integrated operations of connected devices will be necessary. To this end, new research related to the following technologies is scheduled: extended reality (XR) for effectively supporting technologies such as augmented reality (AR), virtual reality (VR), and mixed reality (MR), 5G performance improvement and complexity reduction by utilizing artificial intelligence (AI) and machine learning (ML), AI service support, metaverse service support, and drone communication.

[0007] Such development of 5G mobile communication systems will serve as a foundation for developing not only new waveforms for providing coverage in the terahertz band for 6G mobile communication technology, multi-antenna transmission technologies (such as full-dimensional MIMO (FD-MIMO), array antennas, and massive antennas), metamaterial-based lenses and antennas for improving terahertz band signal coverage, high-dimensional spatial multiplexing technology using orbital angular momentum (OAM), and reconfigurable smart surfaces (RIS), but also full-duplex technology for improving frequency efficiency and improving system networks for 6G mobile communication technology, AI-based communication technology for achieving system optimization by utilizing satellites and AI from the design stage and internalizing end-to-end AI support functions, and next-generation distributed computing technology for achieving services with a complexity that exceeds the limits of UE operating capabilities by utilizing ultra-high performance communication and computing resources.

[0008] NR MBS may refer to a multicast service where the intended common content is targeted to a group of UEs. The UEs join a multicast group in a multicast coverage area and broadcast the service. The coverage area may be one radio cell or larger.

[0009] In a conventional system as defined in the 3rd Generation Partnership Project (3GPP) Release 17 MBS, a group notification or group paging mechanism is used to notify the UE of the activation of a multicast session in the RRC idle (RRC_IDLE) state or the RRC inactive (RRC_INACTIVE) state. Based on the reception of the group notification or group paging, the UE transitions to the RRC connected (RRC_CONNECTED) state and starts receiving one or more multicast sessions. However, there may be UEs receiving multicast sessions in the RRC_INACTIVE state (e.g., 3GPP Release 18 MBS may consider such a scenario).

[0010] A problem in conventional technology relates to a UE that is able to receive MBS multicast services in the RRC_INACTIVE state. In a 3GPP conventional system, multicast services can only be received in the RRC_CONNECTED state. There is no multicast configuration that can be used to receive multicast services in any state other than the RRC_CONNECTED state. In some scenarios, the RRC reconfiguration used to deactivate a multicast session releases one or more multicast MBS radio bearers (MRBs) of the MBS, which may result in the loss of the multicast configuration. In addition, if the UE transitions to the RRC_INACTIVE state, the UE may not receive the multicast service without a valid multicast configuration.

[0011] Therefore, there is a need in the art for systems and methods to configure a UE for NR MBS multicast service reception in an RRC inactive state. Summary of the invention

[0012] Technical issues

[0013] The present disclosure is made to address at least the above problems and / or disadvantages and to provide at least the advantages described below. Therefore, one aspect of the present disclosure is to provide a method and apparatus for configuring a user equipment for multicast reception in a wireless communication system.

[0014] Solution to the problem

[0015] Another aspect of the present disclosure is to provide systems and methods for configuring a UE to efficiently and seamlessly continue receiving one or more multicast services for MBS multicast service reception when the UE transitions from an RRC connected state to an RRC inactive state.

[0016] Another aspect of the present disclosure is to provide systems and methods for configuring a UE for MBS multicast service reception using one or more signaling procedures.

[0017] Another aspect of the present disclosure is to provide a system and method for managing one or more multicast MRB configurations to store, restore, and release the multicast MRB configurations to receive multicast services in an RRC inactive state.

[0018] Another aspect of the present disclosure is to provide systems and methods for managing one or more multicast MRB configurations in different scenarios such as RRC state change, cell selection, cell reselection, RRC reconfiguration, RRC setup, and RRC recovery.

[0019] According to one aspect of the present disclosure, a method for configuring a UE for MBS multicast service reception includes: receiving an RRC reconfiguration message from a base station in an RRC connected state, the RRC reconfiguration message configuring the UE to perform multicast MBS reception in an RRC inactive state, receiving an RRC release message including at least one configuration information about a multicast MRB from the base station, storing at least one configuration information about the multicast MRB in the RRC inactive state; and receiving a multicast MBS session in the RRC inactive state based on the stored at least one configuration information.

[0020] According to one aspect of the present disclosure, a method for MBS in a wireless communication system performed by a base station includes: sending an RRC reconfiguration message to a UE, the RRC reconfiguration message configuring the UE to perform multicast MBS reception in an RRC inactive state, sending an RRC release message including at least one configuration information about a multicast MRB to the UE, and sending a multicast MBS session to the UE, wherein the at least one configuration information about the multicast MRB is stored in the RRC inactive state, and wherein the multicast MBS session associated with the RRC inactive state is based on the stored at least one configuration information.

[0021] According to one aspect of the present disclosure, a UE, used for MBS in a wireless communication system, includes a transceiver and a controller, the controller being configured to receive an RRC reconfiguration message from a base station in an RRC connected state, the RRC reconfiguration message configuring the UE to perform multicast MBS reception in an RRC inactive state, receive an RRC release message including at least one configuration information about a multicast MRB from the base station, store at least one configuration information about the multicast MRB in the RRC inactive state, and receive a multicast MBS session in the RRC inactive state based on the at least one stored configuration information.

[0022] According to aspects of the present disclosure, a base station, used for MBS in a wireless communication system, includes: a transceiver; and

[0023] a controller configured to send an RRC reconfiguration message to the UE, the RRC reconfiguration message configuring the UE to perform multicast MBS reception in an RRC inactive state, send an RRC release message including at least one configuration information about the multicast MRB to the UE, and

[0024] A multicast MBS session is transmitted to the UE, wherein at least one configuration information regarding the multicast MRB is stored in an RRC inactive state, and wherein the multicast MBS session associated with the RRC inactive state is based on the at least one stored configuration information.

[0025] Advantageous Effects of the Invention

[0026] The advantages and salient features of the present invention will become apparent to those skilled in the art through the following detailed description of exemplary embodiments of the present invention disclosed in conjunction with the accompanying drawings.For a more enhanced communication system, a method and network for configuring user equipment for multicast reception in a wireless communication system is needed. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The above and other aspects, features and advantages of certain embodiments of the present disclosure will become more apparent through the following description in conjunction with the accompanying drawings, in which:

[0028] Figure 1 A system for configuring a UE for MBS multicast service reception in a wireless network according to an embodiment is shown;

[0029] Figure 2 The internal structure of the controller of the UE according to the embodiment is shown;

[0030] Figure 3 The internal structure of the controller of the network device according to the embodiment is shown;

[0031] Figure 4 A method for configuring a UE for MBS multicast service reception according to an embodiment is shown;

[0032] Figure 5 A method for configuring a UE for receiving a multicast session in an RRC inactive state using an RRC reconfiguration message according to an embodiment is shown;

[0033] Figure 6 A method of configuring a UE for receiving a multicast session in an RRC inactive state using an RRC release with a suspendConfig message according to an embodiment is shown;

[0034] Figure 7A method for releasing a multicast configuration for an RRC inactive state when an RRC connection recovery procedure is performed in a different cell according to an embodiment is shown;

[0035] Figure 8 A method of releasing a multicast configuration for an RRC inactive state when an RRC connection recovery procedure has been initiated according to an embodiment is shown;

[0036] Fig. 9 A method of releasing a multicast configuration for an RRC inactive state when a cell reselection is performed according to an embodiment is shown; and

[0037] Fig.10 A method of releasing a multicast configuration for an RRC inactive state when a change in a mode of service delivery is performed according to an embodiment is shown. DETAILED DESCRIPTION

[0038] Embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. For the sake of clarity and conciseness, descriptions of well-known components and processing techniques are omitted.

[0039] The embodiments described herein are not necessarily mutually exclusive and may be combined with one or more other embodiments to form new embodiments. Unless otherwise specified, the term "or" as used herein refers to a non-exclusive or. The examples used herein are intended only to facilitate understanding of how to practice the embodiments herein and should not be interpreted as limiting the scope of the embodiments herein.

[0040] The accompanying drawings are used to help understand various technical features, and it should be understood that the embodiments presented herein are not limited by the accompanying drawings. Therefore, the present disclosure should be interpreted as extending to any changes, equivalents and substitutes other than those specifically set forth in the accompanying drawings. Although the terms first, second, etc. can be used to describe various elements in this article, these elements should not be limited by these terms because they are only used to distinguish one element from other elements.

[0041] Embodiments herein provide systems and methods for configuring UEs for NR MBS multicast service reception. In particular, UEs supporting 3GPP Release 18 MBS may be able and / or configured to receive multicast services in the RRC_INACTIVE state, while UEs belonging to previous 3GPP Release 17 MBS may not be able and / or configured to receive multicast services in the RRC_INACTIVE state. Coexistence of these two sets of UEs in the same cell / network is feasible and needs to be supported.

[0042] In legacy (e.g., 3GPP Rel 17 MBS), when a UE receives an RRC reconfiguration for deactivation including a multicast MRB release for a temporary mobile group identity (TMGI), the UE releases the multicast MRB configuration, and when the UE transitions to the RRC_IDLE state or the RRC_INACTIVE state (e.g., the network releases the UE due to inactivity), the UE monitors the group notification or group paging for activating the TMGI, and may return to the RRC_CONNECTED state to receive the multicast configuration through dedicated signaling and continue the multicast session. However, if the multicast configuration has been released while the UE is in the RRC_CONNECTED state, and then the UE is released to the RRC_INACTIVE state, the UE that is capable of or needs to receive the multicast session in the RRC_INACTIVE state may not be able to receive the multicast service in the RRC_INACTIVE state. The UE may be forced to be in the RRC_CONNECTED state, which may increase network congestion and UE power consumption. To overcome these problems, when an RRC reconfiguration with MRB release is received for deactivation in the RRC_CONNECTED state (e.g., by RRC reconfiguration), a UE capable of and / or configured to receive multicast in the RRC_INACTIVE state does not release the multicast configuration. Alternatively, when an RRC reconfiguration with MRB release is received for deactivation, the UE stores the configuration of the multicast MRB that the UE needs to receive multicast in the RRC_INACTIVE state. For example, the UE may store only the applicable or relevant parts of the configuration according to the RRC reconfiguration message that are needed in the RRC_INACTIVE state. The UE may store these configurations in an inactive access stratum (AS) context.

[0043] Figure 1 A system 100 for configuring a UE for MBS multicast service reception in a wireless network according to an embodiment is shown.

[0044] refer to Figure 1 , the system 100 includes a UE 102 and a network device 104. The UE 102 also includes a controller 106, a transceiver 108, and a memory 110.

[0045] The controller 106 is configured to receive and manage NR MBS reception in the RRC_INACTIVE state.

[0046] Figure 2 The internal composition of the controller of the UE according to the embodiment is shown.

[0047] refer to Figure 2, the controller 106 includes a multicast indication circuit 202, a memory 204, a configuration circuit 206, an RRC state circuit 208 and a notification circuit 210, as shown Figure 2 shown.

[0048] The multicast indication circuit 202 sends an indication of at least one of a capability and / or preference for MBS multicast service reception in the RRC_INACTIVE state to the network device 104. The network device 104 may be a radio access node such as a base station (gNB) or a core network node such as an access and mobility management function (AMF). The multicast indication circuit 202 transmits the indication in the RRC_CONNECTED state for receiving the multicast service in the RRC_INACTIVE state. The multicast indication circuit 202 sends a signaling message to the network device 104 for indicating the capability and / or preference for MBS multicast service reception in the RRC_INACTIVE state. For example, the signaling message may carry at least one of a bit or field or feature flag for supporting multicast reception in the RRC_INACTIVE state. The UE 102 indicates the UE preference for multicast reception in the RRC_INACTIVE state to the network device 104 through a signaling message, the signaling message including but not limited to a UE Assistance Information (UAI) signaling message, an MBS Interest Indication (MII) signaling message, and a different RRC signaling message. The UAI or MII may be reported more dynamically when the UE preference changes due to multiple parameters, such as the multicast service of interest, the corresponding quality of service (QoS) requirements, the UE channel conditions (e.g., better signal conditions enable reliable multicast reception in the RRC_INACTIVE state, while poor signal conditions enable reliable reception in the RRC_CONNECTED state), battery power, activity level, presence / absence of other unicast services, or changes in packet data unit (PDU) sessions. The UAI or MII may also carry some assistance information from the UE side, which helps the network operation in providing appropriate configuration for multicast service reception in the RRC_INACTIVE feature of the UE 102. Such preference or assistance information, such as mbs-InactiveAssistance, may be configured as mbs-InactiveAssistanceConfig to the UE 102 via Otherconfig in the RRC reconfiguration message. The UE 102 may also be configured with an inhibit timer (eg, Txyz) to control excessive signaling of such preference and / or assistance information from the UE 102 to the network device 104. The timer Txyz may be started when the UAI carrying mbs-InactiveAssistance is sent.The timer Txyz may be stopped when the mbs-InactiveAssistanceConfig is released during the connection reestablishment / recovery procedure or when an mbs-InactiveAssistanceConfig set to released is received.

[0049] The memory 204 receives one or more multicast MRB configurations from the network device 104 in the RRC_CONNECTED state by an RRC release with a pause configuration message. Each multicast MRB configuration may include one or more configuration parameters. Each multicast MRB configuration may be a single field indicating support for multicast MRB in the RRC_INACTIVE state and / or may include a set of configuration parameters to be utilized by the UE 102 in the RRC_INACTIVE state. Each configuration parameter corresponds to at least one of each multicast service / MRB, a set of multicast services / MRBs, and an overall multicast service / MRB. The network device 104 indicates to the UE 102 all configurations and parameters received in the RRC_CONNECTED state, and indicates the configuration parameters applicable in the RRC_INACTIVE state. Alternatively, a set of reduced configurations and parameters that the UE 102 needs to utilize in the RRC_INACTIVE state may be provided to the UE 102. The configuration parameters correspond to one or more multicast radio bearer (RB) configuration parameters, one or more medium access control (MAC) configuration parameters, and one or more physical layer configuration parameters. The memory 204 receives the multicast MRB configuration based on the capability and preference of the MBS multicast service reception, and receives it through the RRC reconfiguration message. The memory 204 can store the relevant multicast MRB configuration required for the MBS multicast service reception in the RRC_INACTIVE state according to the received multicast MRB configuration in the RRC_CONNECTED state. When the UE 102 transitions to the RRC_INACTIVE state, the memory 204 can store the relevant multicast MRB configuration (mbs-InactiveAssistanceConfig) in the UE inactive AS context. The memory 204 receives the multicast MRB configuration through the RRC release with the suspension configuration message. The memory 204 can maintain the relevant multicast MRB configuration required for the MBS multicast service reception in the RRC_INACTIVE state according to the received multicast MRB configuration in the RRC_CONNECTED state. When the UE 102 transitions from the RRC_CONNECTED state to the RRC_INACTIVE state, the memory 204 can continue to receive the multicast MRB configuration in the RRC_INACTIVE state without suspending the multicast MRB configuration. The multicast MRBs for which the configuration is not released and / or the configuration is stored and / or the multicast MRB is not suspended are explicitly configured or signaled to the UE 102 to be receivable for multicast in the RRC_INACTIVE state. The indicated multicast MRBs are explicitly configured or signaled to the UE 102 to be receivable for multicast services in the RRC_INACTIVE state.

[0050] The configuration circuit 206 may communicate with the memory 204 and configure the received multicast MRB configuration for receiving multicast services in the RRC_INACTIVE state (ie, when the UE 102 switches from the RRC connected state to the RRC_INACTIVE state).

[0051] The RRC state circuit 208 may verify one or more RRC connection initiation procedures from the network device 104. The RRC state circuit 208 may verify at least one of an RRC connection recovery procedure or an RRC re-establishment procedure, an RRC release procedure, and a cell reselection procedure. The RRC state circuit 208 may determine whether the RRC connection recovery procedure has been initiated to a cell different from the cell in which the multicast MRB configuration is configured in the RRC_INACTIVE state. If the RRC connection recovery procedure or the RRC re-establishment procedure has been initiated, the RRC state circuit 208 may release the configured multicast MRB configuration (mbs-InactiveAssistanceConfig) from the UE inactive AS context (if stored). If the timer is set and running, the UE 102 may stop the timer Txyz. When the multicast MRB configuration is configured in the RRC_INACTIVE state, the RRC state circuit 208 may determine whether the RRC connection recovery procedure has been initiated. If the RRC connection recovery procedure has been initiated, the RRC state circuit 208 may release the multicast MRB configuration (if stored) from the UE inactive AS context. When the multicast MRB configuration is configured in the RRC inactive state, the RRC state circuit 208 may determine whether an RRC release procedure has been initiated. If the RRC release procedure has been initiated, the RRC state circuit 208 may release the multicast MRB configuration (if stored) from the UE inactive AS context. When the multicast MRB configuration is configured in the RRC_INACTIVE state, the RRC state circuit 208 may determine whether a cell reselection procedure occurs. If a cell reselection procedure has been initiated, the RRC state circuit 208 may release the configured multicast MRB configuration. If the timer is set and running, the UE 102 may stop the timer.

[0052] The notification circuit 210 receives one or more notifications from the network device 104. The notification circuit 210 receives a notification from the network device 104 that the mode of service delivery is changed to a broadcast mode of service delivery. The notification circuit 210 may release the multicast MRB configuration (mbs-multicast-InactiveConfig) (if configured) based on the received notification. The notification circuit 210 may monitor the group notification provided by the group paging and / or multicast MBS control channel (MCCH) message from the network device 104 in the RRC_INACTIVE state for at least one of multicast session activation, multicast session deactivation, and multicast session release. If the group notification received by the notification circuit 210 is a multicast session activation, the notification circuit 210 restores the associated multicast MRB of the stored multicast MRB configuration, continues to receive one or more multicast MRBs / services in the RRC_INACTIVE state, and continues to monitor the group notification. If the group notification received by the notification circuit 210 is a multicast session activation, the notification circuit 210 uses the multicast MRB configuration for the associated MRB received through the RRC release with the pause configuration message in the RRC_CONNECTED state, continues to receive the associated multicast MRB / service in the RRC_INACTIVE state, and continues to monitor the group notification. If the group notification received by the notification circuit 210 is a multicast session deactivation, the notification circuit 210 stops receiving the associated multicast MRB / service of the stored multicast MRB configuration, retains the stored multicast MRB configuration of the associated multicast MRB, and continues to monitor the group notification of the associated temporary mobile group identity (TMGI). If the group notification received by the notification circuit 210 is a multicast session deactivation, the notification circuit 210 retains the multicast MRB configuration for the associated multicast MRB received through the RRC release with the pause configuration message in the RRC_CONNECTED state. The notification circuit 210 further stops receiving the associated multicast MRB / service and continues to monitor the group notification of the associated TMGI. If the group notification received by the notification circuit 210 is a multicast session release, the notification circuit 210 removes the associated multicast MRB of the stored multicast MRB configuration, removes the stored multicast MRB configuration of the associated multicast MRB, and terminates monitoring the group notification of the associated TMGI. If the group notification received by the notification circuit 210 is a multicast session release, the notification circuit 210 removes the multicast MRB configuration for the associated multicast MRB received by the RRC release with the suspend configuration message in the RRC_CONNECTED state, removes the associated multicast MRB, and terminates monitoring the group notification of the associated TMGI.

[0053] The network device 104 also includes a controller 112, a transceiver 114, and a memory 116. Figure 1The controller 112 sends a multicast MRB configuration to at least one UE 102 and instructs the RRC initiation process and the multicast initiation session.

[0054] Figure 3 The internal structure of the controller of the network device according to the embodiment is shown.

[0055] refer to Figure 3 , the controller 112 includes a multicast MRB configuration circuit 302 , an RRC connection circuit 304 , and a multicast session circuit 306 .

[0056] The multicast MRB configuration circuit 302 receives an indication of capability and / or preference for MBS multicast service reception in the RRC_INACTIVE state from the multicast indication circuit 202 of the UE 102. The multicast MRB configuration circuit 302 sends a multicast MRB configuration to the memory 204 of the UE 102 in the RRC_CONNECTED state based on the indication of capability and / or preference for MBS multicast service reception in the RRC_INACTIVE state.

[0057] The RRC connection circuit 304 initiates one or more RRC procedures with the UE 102, based on which the UE 102 releases the stored and / or configured multicast MRB configuration. The RRC procedures are not limited to the RRC connection recovery procedure and the cell reselection procedure.

[0058] The multicast session circuit 306 sends notifications about multiple sessions, such as a change in the mode of delivery of the multicast session service of interest, multicast session activation, multicast session deactivation, and multicast session release. The multicast session circuit 306 may notify the notification circuit 210 of the UE 102 of the change in the mode of delivery of the multicast session service of interest to the broadcast mode of delivery of the multicast session service of interest. Based on the notification, the notification circuit 210 of the UE 102 may release the mbs-multicast-InactiveConfig (if configured). Upon such a change in service delivery, the network device 104 may experience more UEs using the multicast session in the service coverage area. When the UE 102 is in the RRC_INACTIVE state, the multicast session circuit 306 sends a group notification (e.g., the notification may be provided by a group paging and / or a multicast MBS control channel (MCCH) message) to the notification circuit 210 of the UE 102, indicating at least one of the multicast session activation, the multicast session deactivation, and the multicast session release. Based on the received group notification, the notification circuit 210 of the UE 102 may restore or remove the multicast MRB configuration.

[0059] Controller 106 and controller 112 can process and execute data of the internal components of UE 102 and network device 104. Controller 106 and controller 112 can be configured to execute instructions stored in memory 110 and memory 116. Controller 106 and controller 112 may include one or more of microprocessors, circuits, and other hardware configured for processing. Controller 106 and controller 112 may be at least one of a single processor, multiple processors, multiple homogeneous or heterogeneous cores, multiple central processing units (CPUs) of different types, microcontrollers, special media, and other accelerators. Controller 106 and controller 112 may be an application processor (AP), a graphics processing unit such as a graphics processing unit (GPU), a visual processing unit (VPU), and / or an AI-specific processor such as a neural processing unit (NPU).

[0060] Multiple circuits of the controller 106 of the UE 102 can communicate with the network device 104 via the transceiver 108. Multiple circuits of the controller 112 of the network device 104 can communicate with the UE 102 via the transceiver 114. The communication circuits 108 and 114 can be in the form of wired networks or wireless communication network circuits. The wireless communication network may include, but is not limited to, a global positioning system (GPS), a global system for mobile communications (GSM), wireless fidelity (Wi-Fi), Bluetooth low energy consumption, and near field communication (NFC). Depending on the use environment, wireless communication may also include one or more of the following: Bluetooth, ZigBee, short-range wireless communication (such as ultra-wideband (UWB)) and medium-range wireless communication (such as Wi-Fi) or long-range wireless communication (such as 3G / 4G / 5G / 6G and non-3GPP technologies or WiMAX).

[0061] UE 102 and network device 104 may include Figure 1-Figure 3 The labels or names of the circuits are for illustration purposes only and do not limit the scope of the present invention. One or more circuits may be combined together to perform the same or substantially similar functions in UE 102 and network device 104.

[0062] Upon transitioning to the RRC_INACTIVE state, UE 102 may store the mbs-InactiveAssistanceConfig in the UE inactive AS context.

[0063] Upon initiating the RRC re-establishment procedure, UE 102 may release mbs-InactiveAssistanceConfig (if configured). UE 102 may stop timer Txyz if it is running.

[0064] Upon cell reselection, UE 102 releases mbs-InactiveAssistanceConfig (if configured). If timer Txyz is running, UE 102 may stop timer Txyz.

[0065] The UE 102 may be pre-configured or configured for multicast reception in RRC_INACTIVE through dedicated signaling messages such as an RRC reconfiguration message and multicast MRB configuration.

[0066] Figure 4 A method 400 for configuring a UE 102 for MBS multicast service reception according to an embodiment is shown.

[0067] refer to Figure 4 In step 402, the network device 104 receives an indication of a capability and / or preference for MBS multicast service reception in the RRC_INACTIVE state from the UE 102. The indication has been received in the RRC_CONNECTED state.

[0068] In step 404, after receiving the indication of the capability and / or preference for MBS multicast service reception in the RRC_INACTIVE state, the network device 104 sends one or more multicast MRB configurations to the UE 102 in the RRC_CONNECTED state.

[0069] In step 406, UE 102 receives the multicast MRB configuration via the RRC release with suspend configuration message.

[0070] In step 408, UE 102 stores the relevant multicast MRB configuration for MBS multicast service reception in the RRC_INACTIVE state in the UE inactive AS context according to the received multicast MRB configuration in the RRC connected state.

[0071] In step 410, when UE 102 transitions from the RRC connected state to the RRC_INACTIVE state, UE 102 continues to receive the multicast MRB configuration in the RRC_INACTIVE state without suspending the multicast MRB configuration.

[0072] In step 412, UE 102 configures the received multicast MRB configuration for MBS multicast service reception in RRC_INACTIVE state.

[0073] The various actions in method 400 may be performed in the order presented, in a different order, or simultaneously. In addition, in some embodiments, the Figure 4 Some of the actions listed in .

[0074] Figure 5 A method 500 of configuring the UE 102 for receiving a multicast session in the RRC_INACTIVE state using an RRC reconfiguration message according to an embodiment is shown.

[0075] refer to Figure 5 , the UE 102 may be pre-configured or configured for MBS multicast service reception in the RRC_INACTIVE state via a dedicated signaling message (eg, an RRC reconfiguration message and one or more multicast MRB configurations).

[0076] In step 502, when UE 102 is in RRC_CONNECTED state, UE 102 receives an RRC reconfiguration message with multicast MRB configuration. The RRC reconfiguration message also provides configuration and / or indication of one or more multicast MRBs that can be received in RRC_INACTIVE state. UE 102 stores and retains these related configurations while transitioning from RRC_CONNECTED state to RRC_INACTIVE state.

[0077] In step 504, UE 102 determines whether an RRC release message has been received from network device 104. If UE 102 has received the RRC release message, then in step 506, UE 102 transitions to the RRC_INACTIVE state.

[0078] If the UE 102 has not received the RRC release message, the method returns to step 502. In step 508, the UE 102 continues to receive the multicast MRB configuration in the activated state using the stored or retained related multicast MRB.

[0079] In step 510, the UE 102 monitors a group notification (e.g., a group paging or MCCH message) from the network device 104 in the RRC_INACTIVE state for at least one of a multicast session activation, a multicast session deactivation, and a multicast session release. In step 512, the UE 102 determines whether the UE 102 has received a group notification (e.g., a group paging) to activate a multicast MRB through a multicast session activation notification. If the group notification is a multicast session activation, then in step 514, the UE 102 restores the associated multicast MRB of the stored multicast MRB configuration and continues to receive the multicast MRB / service in the RRC_INACTIVE state. The UE 102 continues to monitor the group notification (e.g., monitor for possible session deactivation).

[0080] If the UE 102 has not received the group notification as a multicast session activation, then in step 516, the UE 102 determines whether the UE 102 has received a group notification (e.g., an MCCH message) to deactivate the multicast MRB via a multicast session deactivation notification. If the group notification is a multicast session deactivation, then in step 518, the UE 102 stops receiving the associated multicast MRB / service of the stored multicast MRB configuration, retains the stored MRB configuration of the associated multicast MRB, and continues to monitor the group notification (e.g., monitor for possible session activation).

[0081] If the UE 102 has not received the group notification as a multicast session deactivation, then in step 520, the UE 102 determines whether the UE 102 has received a group notification (e.g., an MCCH message) to release the multicast MRB through a multicast session release notification. If the group notification is a multicast release, then in step 522, the UE 102 removes the associated multicast MRBs of the stored multicast MRB configuration, removes the stored multicast MRB configurations of the associated multicast MRBs, and terminates monitoring the group notification. If the UE 102 has not received the group notification as a multicast session release, the method returns to step 508, and the UE 102 continues to receive the multicast MRB in the activated state.

[0082] The various actions in method 500 may be performed in the order presented, in a different order, or simultaneously. In some embodiments, the Figure 5 Some of the actions listed in .

[0083] The UE 102 may store only the applicable or relevant portions of the RRC reconfiguration required in the RRC_INACTIVE state. For example, the Point-To-Multipoint (PTM) discontinuous reception (DRX) configuration for the multicast MRB received in the RRC reconfiguration message may be partially or completely preserved, which may be utilized in the RRC_INACTIVE state. These configurations may include multicast MBS radio bearer (MRB) configuration, and also MAC-CellGroupConfig configuration and PhysicalCellGroupConfig configuration, but exclude all point-to-point (PTP) configurations, hybrid automatic repeat request (HARQ) configurations (e.g., HARQ feedback mode, HARQ feedback enable), HARQ retransmission (e.g., DRX round trip time (RTT) timer, DRX retransmission timer), channel state information (CSI) configuration, sounding reference signal (SRS) configuration, unicast bandwidth part (BWP) configuration (e.g., only MBS Crest Factor Reduction (CFR) configuration is relevant), and timing advance (TA) timer configuration. In a multicast MRB configured with one PTP radio link control (RLC) entity and one PTM RLC entity, the PTP RLC may be released upon RRC release (e.g., transition to RRC_INACTIVE), while the PTM RLC may be maintained. In a multicast MRB configured with only one PTP RLC, the multicast MRB is maintained upon RRC release (eg, transition to RRC_INACTIVE state) and is switched from the PTP RLC to the PTM RLC.

[0084] Figure 6 A method 600 of configuring the UE 102 for receiving a multicast session in the RRC_INACTIVE state using an RRC release with a suspendConfig message is shown according to an embodiment.

[0085] refer to Figure 6 , UE 102 is capable and / or configured to receive multicast services in the RRC_INACTIVE state.

[0086] In step 602, when the UE 102 with an activated session in the RRC_CONNECTED state is released to the RRC_INACTIVE state by the network device 104 through the RRC release with the suspendConfig message, the UE 102 maintains the relevant multicast MRB configuration (e.g., at least a set of parameters required to receive multicast in RRC_INACTIVE) and continues to receive the relevant multicast session in the RRC_INACTIVE state. Therefore, when the UE 102 transitions to the RRC_INACTIVE state, the UE 102 does not suspend the relevant multicast MRB. This is different from the traditional system, which is not able to and / or is not configured to receive multicast in RRC_INACTIVE. The RRC message indicates the multicast MRB that has not been suspended and the suspended multicast MRB when the UE 102 transitions to the RRC_INACTIVE state.

[0087] The multicast MRBs for which the configuration is not released and / or the configuration is stored and / or the multicast MRB is not suspended are explicitly configured or signaled to the UE 102 to be receivable for multicast in RRC_INACTIVE.

[0088] In step 604, UE 102 determines whether an RRC release with suspendConfig message including an mbs-multicast-InactiveConfig for receiving multicast / MRB in the RRC_INACTIVE state has been received from network device 104. If UE 102 has received an RRC release with suspendConfig message, then in step 606, UE 102 transitions to the RRC_INACTIVE state. UE 102 may store the mbs-multicast-InactiveConfig in the inactive AS context. If UE 102 has not received an RRC release message, the method returns to step 602. In step 608, UE 102 continues to receive the multicast MRB configuration in the active state with the associated multicast MRB according to mbs-multicast-InactiveConfig.

[0089] In step 610, the UE 102 monitors a group notification (e.g., group paging and / or MCCH message) from the network device 104 in the RRC_INACTIVE state for at least one of a multicast session activation, a multicast session deactivation, and a multicast session release. In step 612, the UE 102 determines whether the UE 102 has received a group notification (e.g., group paging) to activate a multicast MRB through a multicast session activation notification. If the group notification is a multicast session activation, in step 614, the UE 102 utilizes the multicast MRB configuration received from mbs-multicast-InactiveConfig for the associated multicast MRB through an RRC release with a suspend configuration message in the RRC_CONNECTED state, and continues to receive the associated multicast MRB / service in the RRC_INACTIVE state. The UE continues to monitor the group notification (e.g., possible session deactivation).

[0090] In step 616, if the UE 102 has not received the group notification as a multicast session activation, the UE 102 determines whether the UE 102 has received a group notification (e.g., MCCH message) to deactivate the multicast MRB through a multicast session deactivation notification. If the group notification is a multicast session deactivation, in step 618, the UE 102 remains in the RRC_CONNECTED state, releases the multicast MRB configuration for the associated multicast MRB received from mbs-multicast-InactiveConfig through an RRC with a suspend configuration message, stops receiving the associated multicast MRB / service, and continues to monitor the group notification.

[0091] If the UE 102 has not received the group notification as a multicast session deactivation, then in step 620, the UE 102 determines whether the UE 102 has received a group notification (e.g., an MCCH message) to release the multicast MRB through a multicast session release notification. If the group notification is a multicast release, then in step 622, the UE 102 removes the multicast MRB configuration for the relevant multicast MRB received from mbs-multicast-InactiveConfig through an RRC release with a suspend configuration message in the RRC_CONNECTED state, removes the relevant multicast MRB and terminates monitoring the group notification. If the UE 102 has not received the group notification as a multicast session release, the method returns to step 608, and the UE 102 continues to receive the multicast MRB in the activated state.

[0092] The various actions in method 600 may be performed in the order presented, in a different order, or simultaneously. In addition, in some embodiments, the Figure 6 Some of the actions listed in .

[0093] Considering a UE 102 capable of or configured to receive multicast in the RRC_INACTIVE state, an example specification is provided for the "Multicast MRB Release" procedure as follows:

[0094] 5.3.5.6.6 Multicast MRB Release

[0095] UE 102 should:

[0096] 1> for each MRB-Identity value included in the MRB-ToReleaseList that is part of the current UE configuration; or

[0097] 1> For each MRB-Identity value released as a result of complete configuration according to 5.3.5.11:

[0098] 2> If MRB-Identity is configured to be receivable in RRC_INACTIVE, the UE 102 stores the (relevant) configuration of the multicast MRB;

[0099] 2> Release the PDCP entity and MRB-Identity;

[0100] 2> If no other multicast MRB is configured with the same TMGI as the one configured for the released multicast MRB:

[0101] 3> Instruct the upper layer to release the user plane resources of TMGI.

[0102] NOTE 1: If the MRB-TorReleaseList includes any MRB-Identity value that is not part of the current UE configuration, the UE 102 does not consider the message to be erroneous.

[0103] Note 2: Whether the RLC and MAC entities associated with the PDCP entity are reset or released is determined by CellGroupConfiguration.

[0104] RRC Release with suspendConfig provides a configuration for multicast MRB (mbs-multicast-InactiveConfig), which will be used for multicast reception in RRC_INACTIVE state. UE 102 may store mbs-multicast-InactiveConfig in an inactive AS context. An example of the specification of suspendConfig is as follows:

[0105]

[0106]

[0107]

[0108] MBS-multicast-InactiveConfig field description:

[0109] MBS-InactiveMacConfig-r18 may be used to configure MBS radio bearers for multicast reception in RRC_IANCTIVE state.

[0110] MBS-InactiveMacConfig-r18 may be used to configure MAC parameters (including DRX) for multicast reception in the RRC_INACTIVE state.

[0111] MBS-InactivePhyConfig-r18 may be used to configure cell group specific L1 parameters for multicast in RRC_INACTIVE state.

[0112] The aforementioned radio bearer configuration parameters, MAC configuration parameters and physical layer configuration parameters may also be constructed or grouped according to the PTM configuration of the MBS broadcast PTM configuration.

[0113] A combination of methods may be utilized, namely, storing relevant configuration according to an RRC reconfiguration message for a multicast MRB to receive multicast in an RRC_INACTIVE state (e.g., the configuration of a multicast MRB that is activated in RRC_CONNECTED), and providing relevant configuration for a multicast MRB to receive multicast in an RRC_INACTIVE state (e.g., the configuration of a multicast MRB that is deactivated in RRC_CONNECTED) using an RRC release with a suspendConfig message.

[0114] Figure 7 A method 700 of releasing a multicast configuration for an RRC_INACTIVE state when an RRC connection recovery procedure is performed in a cell different from the cell that provided the configuration is shown according to an embodiment.

[0115] refer to Figure 7In step 702, UE 102 receives an RRC release message with suspendConfig including mbs-multicast-InactiveConfig for receiving multicast MRBs in RRC_INACTIVE state. In step 704, UE 102 transitions from RRC_CONNECTED state to RRC_INACTIVE state.

[0116] In step 706, UE 102 determines whether an RRC connection recovery procedure has been initiated by network device 104 to a cell different from the cell in which the multicast MRB configuration is configured in the RRC inactive state. If the RRC connection recovery procedure has been initiated, UE 102 releases the multicast MRB configuration mbs-multicast-InactiveConfig (if configured) in step 708. If the RRC connection recovery procedure has not been initiated, step 706 is continued.

[0117] The various actions in method 700 may be performed in the order presented, in a different order, or simultaneously. In some embodiments, the Figure 7 Some of the actions listed in .

[0118] When initiating the RRC connection recovery procedure, UE 102 should:

[0119] 1> if UE 102 performs connection recovery in a cell different from the cell in which mbs-multicast-InactiveConfig is configured; and

[0120] 2>Release mbs-multicast-InactiveConfig, if configured.

[0121] Figure 8 A method 800 of releasing a multicast configuration for an RRC_INACTIVE state from an inactive AS context when an RRC connection recovery procedure has been initiated according to an embodiment is shown.

[0122] refer to Figure 8 In step 802, UE 102 receives RRC release with suspendConfig including mbs-multicast-InactiveConfig for receiving multicast MRBs in RRC_INACTIVE state. In step 804, UE 102 transitions from RRC_CONNECTED state to RRC_INACTIVE state.

[0123] In step 806, when the multicast MRB configuration is configured in the RRC_INACTIVE state, the UE 102 determines whether the RRC connection recovery procedure has been initiated by the network device 104. If the RRC connection recovery procedure has been initiated, the UE 102 releases the multicast MRB configuration mbs-multicast-InactiveConfig (if stored) from the UE inactive AS context in step 808. If the timer Txyz is running, the UE 102 stops the timer Txyz. If the RRC connection recovery procedure has not been initiated, the execution of step 806 continues.

[0124] The various actions in method 800 may be performed in the order presented, in a different order, or simultaneously. In some embodiments, the Figure 8 Some of the actions listed in .

[0125] In an example, upon initiating the RRC connection recovery procedure, the UE 102 should:

[0126] 1> Release mbs-InactiveAssistanceConfig from the UE Inactive AS Context, if stored; and

[0127] 2> Stop timer Txyz, if running.

[0128] Fig. 9 A method 900 of releasing a multicast configuration for an RRC_INACTIVE state when performing cell reselection according to an embodiment is shown.

[0129] refer to Fig. 9 In step 902, UE 102 receives RRC release with suspendConfig including mbs-multicast-InactiveConfig for receiving multicast MRB in RRC_INACTIVE state. In step 904, UE 102 transitions from RRC_CONNECTED state to RRC_INACTIVE state.

[0130] In step 906, when the multicast MRB configuration is configured in RRC inactive, UE 102 determines whether a cell reselection process occurs. If the RRC cell reselection process has been initiated, UE 102 releases the multicast MRB configuration mbs-multicast-InactiveConfig (if configured) in step 908. If the cell reselection process is not initiated, step 906 is continued.

[0131] The various actions in method 900 may be performed in the order presented, in a different order, or simultaneously. In some embodiments, the Fig. 9 Some of the actions listed in .

[0132] In an example, upon initiating a cell reselection procedure, the UE 102 should:

[0133] 1> If cell reselection occurs when mbs-multicast-InactiveConfig is configured:

[0134] 2>Release mbs-multicast-InactiveConfig.

[0135] Fig.10 A method 1000 of releasing a multicast configuration for an RRC_INACTIVE state when a change in a mode of service delivery is performed according to an embodiment is shown.

[0136] refer to Fig.10 In step 1002, UE 102 receives an RRC release with suspendConfig including mbs-multicast-InactiveConfig for receiving multicast MRBs in RRC_INACTIVE state. In step 1004, UE 102 transitions from RRC_CONNECTED state to RRC_INACTIVE state.

[0137] In step 1006, UE 102 determines whether a notification of a change in the mode of service delivery (of the multicast session of interest) to a broadcast mode of service delivery has been received from network device 104. If a change in the mode of service delivery has been initiated, UE 102 releases the multicast MRB configuration mbs-multicast-InactiveConfig (if configured) in step 1008. When such a change in service delivery occurs, the network may experience a large number of UEs using the multicast session in the service coverage area. If a change in the mode of service delivery has not been initiated, execution of step 1006 continues.

[0138] The various actions in method 1000 may be performed in the order presented, in a different order, or simultaneously. In some embodiments, the Fig.10 Some of the actions listed in .

[0139] The network device 104 may notify or configure the UE 102 about the coverage area of ​​the multicast session (e.g., provide a cell or a list of cells for the multicast session in the RRC_INACTIVE state, and the UE 102 may continue to retain and / or use the mbs-multicast-InactiveConfig across these cells, such as when a cell reselection occurs). If the UE 102 performs a cell reselection to a different cell (e.g., outside the coverage area or different from the notified cell list), the UE 102 releases the mbs-multicast-InactiveConfig (if configured).

[0140] When a UE 102 capable of and / or configured to receive multicast in RRC_INACTIVE receives an RRCSetup in response to an RRCReestablishmentRequest or receives an RRCSetup in response to an RRCResumeRequest or RRCResumeRequest1, the UE 102 releases radio resources for established radio bearers (except signaling radio bearer 0 (SRB0)), including releasing RLC entities of a service data adaptation protocol (SDAP) and associated PDCP entities, except for multicast MRBs for MBS multicast services configured to be received in the RRC_INACTIVE state. The UE 102 releases RRC configurations except for default L1 parameter values, default MAC cell group configurations, and common control channel (CCCH) configurations, and except for the RRC configurations for multicast MRBs for MBS multicast services configured to be received in the RRC_INACTIVE state. UE 102 performs the radio bearer configuration procedure including multicast MRB addition / modification or release according to the radioBearerConfig received in RRCSetup. Therefore, UE 102 can consider the existing multicast MRB configuration, MRB-Identity and TMGI when configuring the multicast MRB from RRCSetup. That is, if there is a change in MRB-Identity for the same TMGI in both configurations, it can be resolved. An example specification for the above scenario is as follows:

[0141] The UE shall perform the following actions upon receiving RRCSetup:

[0142] 1> if RRCSetup has been received in response to RRCReestablishmentRequest; or

[0143] 1> If RRCSetup has been received in response to RRCResumeRequest or RRCResumeRequest1:

[0144] 2> discard any stored UE inactive AS context and suspendConfig;

[0145] 2> discard any current AS security context including KRRCenc key, KRRCint key, KUPint key and KUPenc key;

[0146] 2> Release the radio resources for all established RBs except SRB0, including releasing the RLC entity of SDAP and associated PDCP entities, except for multicast MRBs configured or receivable in RRC_INACTIVE state;

[0147] 2> Release the RRC configuration except the default L1 parameter value, the default MAC cell group configuration and the CCCH configuration, and the RRC configuration except the RRC configuration of the multicast MRB configured or receivable in RRC_INACTIVE;

[0148] 2>Indicate the fallback of RRC connection to the upper layer;

[0149] 2> discard any application layer measurement reports that have not yet been sent;

[0150] 2> Notify the upper layer to release all application layer measurement configurations;

[0151] 2> Stop timer T380, if running;

[0152] 1> Perform the cell group configuration process according to the received masterCellGroup and as specified in 5.3.5.5;

[0153] 1> Perform the radio bearer configuration procedure according to the received radioBearerConfig and as specified in 5.3.5.6;

[0154] 1> discard the cell reselection priority information provided by cellReselectionPriorities or inherited from another RAT, if stored;

[0155] Multicast MRBs for which radio resources and RRC (re)configuration have not yet been released are explicitly configured or signaled to the UE 102 to be receivable in the RRC_INACTIVE state.

[0156] If a RRCRelease message with suspendConfig has been received, which is not in response to RRCResumeRequest or RRCResumeRequest1, the UE 102 stores the G-Radio Network Temporary Identifier (RNTI) / G-CS-RNTI or TMGI of the MBS service used in the source primary cell (PCell) in the UE inactive AS context.

[0157] If the RRCRelease message with suspendConfig includes mbs-multicast-InactiveConfig, the UE 102 stores the G-RNTI / G-CS-RNTI or TMGI configured to receive multicast MBS multicast services in RRC_INACTIVE in the UE inactive AS context, as provided in mbs-multicast-InactiveConfig.

[0158] If the RRCRelease message with suspendConfig includes mbs-multicast-InactiveConfig, UE 102 suspends all SRBs and DRBs and multicast MRBs, except for multicast MRBs and SRB0 configured to receive multicast in RRC_INACTIVE state as provided in mbs-multicast-InactiveConfigure, and UE 102 indicates PDCP suspension to the lower layers of all DRBs and multicast MRBs, except for multicast MRBs configured to receive multicast in RRC_INACTIVE state.

[0159] If the RRCRelease message with suspendConfig includes mbs-multicast-InactiveConfig, when the UE 102 enters the RRC_INACTIVE state, the UE 102 performs cell selection so that the UE 102 can camp on or select the same current cell that provides the multicast service. For this purpose, the UE 102 can prioritize the current cells. Alternatively, the UE 102 skips the cell selection step and selects the same current cell for camping and continuing the multicast service.

[0160] The preceding example is as follows:

[0161] 1> If RRCRelease includes suspendConfig:

[0162] 2> Reset MAC and release the default MAC cell group configuration (if any);

[0163] 2> Apply the received suspendConfig in addition to the received nextHopChainingCount (next hop chain count);

[0164] 2> Re-establish the RLC entity for SRB1;

[0165] 2> If a RRCRelease message with suspendConfig has been received in response to RRCResumeRequest or RRCResumeRequest1:

[0166] 3> If timer T319 is running, stop timer T319;

[0167] 3> If timer T319a is running, stop timer T319a;

[0168] 3> In the stored UE inactive AS context:

[0169] 4>Replace the KgNB and KRRCint keys with the current KgNB and KRRCint keys;

[0170] 4>Replace nextHopChainingCount with the value of nextHopChainingCount received in the RRCRelease message;

[0171] 4> replace cellIdentity with the cellIdentity of the cell from which UE 102 has received the RRCRelease message;

[0172] 4> If suspendConfig contains sl-ServingCellInfo (i.e., UE 102 is a L2 U2N remote UE):

[0173] 5>Replace the physical cell identifier with the value of sl-PhysCellId (sl-physical cell ID);

[0174] 5> Replace C-RNTI with the value of sl-UEIdentityRemote;

[0175] 4> Otherwise:

[0176] 5> Replace the C-RNTI with the C-RNTI used in the cell from which UE 102 has received the RRCRelease message;

[0177] 5> replace the physical cell identifier with the physical cell identifier of the cell from which UE 102 has received the RRCRelease message;

[0178] 3>Replace nextHopChainingCount with the value associated with the current KgNB;

[0179] 2> Otherwise:

[0180] 3> Store in the UE inactive AS context the nextHopChainingCount received in the RRCRelease message, the current KgNB and KRRCint keys, the ROHC state, the stored QoS flow to DRB mapping rules, the application layer measurement configuration, the C-RNTI used in the source PCell, the G-RNTI / G-CS-RNTI or TMGI for the MBS service used in the source PCell, the cellIdentity and physical cell identity of the source PCell, the spCellConfigCommon within the ReconfigurationWithSync of the NR PSCell (if configured), and all other parameters configured except the following:

[0181] -Parameters in ReconfigurationWithSync of PCell;

[0182] -Parameters within ReconfigurationWithSync for the NR primary and secondary cells (PSCell), if configured;

[0183] - parameters within the MobilityControlInfoSCG of the E-UTRA Evolved Universal Terrestrial Radio Access (E-UTRA) PSCell, if configured;

[0184] -servingCellConfigCommonSIB (serving cell configuration common SIB);

[0185] -sl-L2RelayUEConfig (sl-L2 relay UE configuration), if configured;

[0186] -sl-L2RemoteUEConfig (sl-L2 remote UE configuration), if configured;

[0187] 3>Store any previously or subsequently received application layer measurement reports for which no segments or complete messages have been submitted to the lower layers for transmission;

[0188] 2> Suspend all SRBs and DRBs and multicast MRBs, except for multicast MRBs and SRB0 that are configured to receive multicast in RRC_INACTIVE;

[0189] 2> Indicate PDCP suspension to the lower layers of all DRBs and multicast MRBs, except for the multicast MRBs configured to receive multicast in RRC_INACTIVE state;

[0190] 2> If t380 is included:

[0191] 3>Start timer T380, where the timer value is set to t380;

[0192] 2> If the RRCRelease message includes waitTime (wait time):

[0193] 3>Start timer T302, where the value is set to waitTime;

[0194] 3> Notify the upper layer that access prohibition applies to all access categories except categories '0' and '2';

[0195] 2> If T390 is running:

[0196] 3> Stop timer T390 of all access categories;

[0197] 3> Execute the actions specified in 5.3.14.4;

[0198] 2> Indicate to the upper layer the suspension of the RRC connection;

[0199] 2> Enter the RRC_INACTIVE state and perform cell selection as specified in TS 38.304

[20] . If the UE 102 is configured to receive multicast in the RRC_INACTIVE state, the UE 102 may prioritize the current cell;

[0200] 1> Otherwise

[0201] 2> Perform actions upon entering the RRC_IDLE state as specified in 5.3.11, where the release cause is "other".

[0202] When UE 102 receives the RRCResume message, UE 102 resumes SRB2 (if suspended), SRB3 (if configured), all DRBs (suspended), and multicast MRBs, except for the multicast MRBs configured to receive multicasts in the RRC_INACTIVE state. That is, the multicast MRBs configured to receive multicasts in the RRC_INACTIVE state are not suspended when entering the RRC_INACTIVE state, and are not resumed when exiting the RRC_INACTIVE state. An example is as follows:

[0203] 5.xyz UE receives RRCResume message

[0204] UE 102 should:

[0205] 1> Resume SRB2 (if suspended), SRB3 (if configured), all DRBs (suspended), and multicast MRBs, except for the multicast MRBs configured to receive multicast in RRC_INACTIVE.

[0206] When UE 102 receives RRCResume, if RRCResume includes fullConfig, UE 102 performs a full configuration procedure by releasing all current dedicated radio configurations except MCG C-RNTI, AS security configuration associated with the master key, SRB1 / SRB2 configuration, DRB / multicast MRB configuration configured by radioBearerConfig or radioBearerConfig2, logged measurement configuration, and multicast MRB configuration configured by mbs-multicast-InactiveConfig in suspendConfig (e.g., multicast MRB configuration configured for multicast reception in RRC_INACTIVE state). An example specification is as follows:

[0207] 5.xyz Complete Configuration

[0208] UE 102 should:

[0209] 1> Release / clear all current private radio configurations except the following:

[0210] -Master Cell Group (MCG) C-RNTI;

[0211] -AS security configuration associated with the master key;

[0212] -SRB1 / SRB2 configuration and DRB / multicast MRB configuration, as configured by radioBearerConfig or radioBearerConfig2.

[0213] - Multicast MRB configuration, as configured by mbs-multicast-InactiveConfig in RRC release with suspendConfig

[0214] - recorded measurement configuration;

[0215] 1> For each TMGI that is part of the current UE configuration:

[0216] 2> Release the SDAP entity;

[0217] 2> Release each multicast MRB associated with the TMGI, as specified in 5.3.5.6.6;

[0218] NOTE 4: This may preserve the TMGI, but remove the Multicast MRB including the MRB-Identity for these bearers from the current UE configuration. The establishment of a Multicast MRB within the AS is described in clause 5.3.5.6.7 using the new configuration. The TMGI acts as an anchor for the association released and re-established Multicast MRB. In the AS, the Multicast MRB re-establishment is equivalent to a new Multicast MRB establishment (including new PDCP and logical channel configuration).

[0219] 1> For each TMGI that is part of the current UE configuration but not added in the mrb-ToAddModList with the same TMGI:

[0220] 2> If the process is triggered due to a reconfiguration with synchronization:

[0221] 3> After successful reconfiguration with synchronization, indicate to the upper layer the release of user plane resources for TMGI;

[0222] 2> Otherwise:

[0223] 3> Immediately indicate to the upper layer the release of user plane resources used for TMGI.

[0224] When a UE 102 capable of or configured to receive multicast in RRC_INACTIVE transitions from RRC_INACTIVE to RRC_IDLE due to an RRC release signaling message from the network or inactivity or release of all multicast sessions in RRC_INACTIVE, the UE 102 releases the multicast MRB configuration.

[0225] When a UE 102 capable of or configured to receive multicast in the RRC_INACTIVE state receives an "activation" of a related multicast session through a group notification (e.g., group paging) from the network, the UE 102 restores the stored configuration of the related multicast MRB and continues to receive the multicast session in the RRC_INACTIVE state. Alternatively, when a UE 102 capable of or configured to receive multicast in the RRC_INACTIVE state receives an "activation" of a related multicast session through a group notification (e.g., group paging) from the network in the RRC_INACTIVE state, the UE 102 utilizes the configuration of the related multicast MRB as received in the mbs-multicast-InactiveConfig included in the SuspendConfig (i.e., through the RRCRelease with the SuspendConfig message when the UE 102 is in the RRC_CONNECTED state), and continues to receive the multicast session in the RRC_INACTIVE state. The UE 102 continues to monitor the group notification for possible session deactivation.

[0226] When a UE 102 capable of or configured to receive multicast in the RRC_INACTIVE state receives deactivation of an associated multicast session (e.g., via a group notification from the network device 104), the UE 102 retains the stored configuration of the associated multicast MRB and continues to monitor the group notification of the associated TMGI. When a UE 102 capable of or configured to receive multicast in the RRC_INACTIVE state receives deactivation of an associated multicast session (e.g., via a group notification from the network device 104 in the RRC_INACTIVE state), the UE 102 retains the configuration of the associated multicast MRB, as included in the received mbs-multicast-InactiveConfig in the SuspendConfig (i.e., via a RRCRelease with a suspendConfig message when the UE 102 is in the RRC_CONNECTED state), and continues to monitor the group notification of the associated TMGI for possible session activation.

[0227] When a UE 102 capable of or configured to receive multicast in the RRC_INACTIVE state receives a release of the associated multicast session (e.g., via a group notification from the network device 104), the UE 102 again removes or discards the stored configuration of the associated multicast MRB and stops monitoring group notifications for at least the associated TMGI. When a UE 102 capable of or configured to receive multicast in the RRC_INACTIVE state receives a "release" of the associated multicast session (e.g., via a group notification from the network device 104 in the RRC_INACTIVE state), the UE 102 removes or discards the configuration of the associated multicast MRB, such as the received mbs-multicast-InactiveConfig included in the SuspendConfig (i.e., via a RRCRelease with a suspendConfig message when the UE is in the RRC_CONNECTED state), and stops monitoring group notifications for the associated TMGI.

[0228] In the RRC_INACTIVE state, the UE 102 only needs to acquire the broadcasted System Information Block 1 (SIB1) and MBS broadcast if the UE 102 can do so without interrupting MBS multicast data reception, ie, the broadcast and unicast / MBS multicast beams are quasi co-located.

[0229] A UE 102 configured to receive multicast in RRC_INACTIVE state monitors group notification in RRC_INACTIVE state for at least one of session activation, deactivation, and release, regardless of a paging early indication (PEI) indicating whether there is paging for a subgroup associated with the UE 102.

[0230] The embodiments disclosed herein may be implemented by at least one software program running on at least one hardware device and performing network management functions to control network elements. Figures 1 to 3 The modules shown in include blocks that may be at least one of a hardware device or a combination of a hardware device and a software device.

[0231] As is conventional in the art, embodiments may be described and illustrated in terms of blocks that perform one or more functions described. These blocks, which may be referred to herein as managers, units, modules, or hardware components, are physically implemented by analog and / or digital circuits (such as logic gates, integrated circuits, microprocessors, microcontrollers, memory circuits, passive electronic components, active electronic components, optical components, hard-wired circuits, etc.), and may optionally be driven by firmware and software. The circuits may be embodied in one or more semiconductor chips, or on a substrate support such as a printed circuit board (PCB). The circuits that make up the blocks may be implemented by dedicated hardware, or by a processor (e.g., one or more programmed microprocessors and associated circuits), or by a combination of dedicated hardware that performs some functions of the blocks and a processor that performs other functions of the blocks. Without departing from the scope of the present disclosure, each block of the embodiment may be physically divided into two or more interacting and discrete blocks, or may be physically combined into more complex blocks.

[0232] Memories 110 and 116 may include one or more volatile and non-volatile memory components that can store data and instructions to be executed by modules of UE 102 and network device 104. Examples of memories 110 and 116 may be, but are not limited to, NAND, embedded multimedia card (eMMC), secure digital (SD) card, universal serial bus (USB), serial advanced technology attachment (SATA), and solid-state drive (SSD). Memories 110 and 116 may also include one or more computer-readable storage media. Examples of non-volatile storage elements may include magnetic hard disks, optical disks, floppy disks, flash memory, or electrically programmable memory (EPROM) or electrically erasable programmable (EEPROM) memory. In some examples, memories 110 and 116 may be considered non-transitory storage media. The term "non-transitory" may indicate that the storage medium is not embodied in a propagation signal. However, the term "non-transitory" should not be interpreted as meaning that memory modules 110 and 116 are non-removable. In certain instances, non-transitory storage media may store data that may change over time, such as in random access memory (RAM) or cache.

[0233] The embodiments disclosed herein describe systems and methods for configuring a UE for NR MBS reception in an RRC inactive state. Therefore, it should be understood that the scope of protection is extended to such a program, and in addition to a computer-readable device having a message therein, such a computer-readable storage device contains a program code device for implementing one or more steps of the method when the program is run on a server or a mobile device or any suitable programmable device. In at least one embodiment, the method is implemented by or together with a software program written in another programming language such as a very high speed integrated circuit hardware description language (VHDL), or by several software modules or one or more VHDLs executed on at least one hardware device. The hardware device can be any kind of portable device that is programmable. The device can also include equipment, which can be, for example, a hardware device, such as an ASIC, or a combination of hardware and software equipment, such as an ASIC and an FPGA, or at least one microprocessor and at least one memory in which a software module is placed. The embodiments described herein can be implemented partially in hardware and partially in software, or by using multiple CPUs.

[0234] While the present disclosure has been described with reference to various embodiments, various changes may be made without departing from the spirit and scope of the present disclosure, which is defined not by the detailed description and embodiments but by the appended claims and their equivalents.

Claims

1. A method for multicast and broadcast service (MBS) in a wireless communication system performed by a user equipment (UE), the method comprising: receiving a radio resource control (RRC) reconfiguration message from a base station in a radio resource control (RRC) connected state, the RRC reconfiguration message configuring the UE to perform multicast MBS reception in an RRC inactive state; receiving, from a base station, an RRC release message including at least one configuration information about a multicast MBS radio bearer (MRB); In an RRC inactive state, storing the at least one configuration information about the multicast MRB; as well as The multicast MBS session is received in the RRC inactive state based on the at least one stored configuration information.

2. The method according to claim 1, in, The at least one configuration information about the MRB includes point-to-multipoint (PTM) configuration information for one or more multicast MBS sessions.

3. The method according to claim 1, further comprising: A group paging message is received from a base station, wherein the group paging message includes at least one of: first information about activation of a multicast MBS session, second information about changing the at least one configuration information about the MRB, third information about whether the multicast MBS session is received in an RRC inactive state, and fourth information about switching the UE from the RRC inactive state to the RRC connected state.

4. The method according to claim 1, in, The same Physical Downlink Control Channel (PDCCH) resources can be used by both connected UEs and inactive UEs for the same multicast MBS session, and Therein, the same Physical Downlink Shared Channel (PDSCH) resources can be used by both connected UEs and inactive UEs for the same multicast MBS session.

5. The method according to claim 1, wherein: Receiving a multicast MBS session in an inactive state includes: identifying whether the at least one configuration information about the MRB is available and whether the UE has joined the multicast MBS session; In case the at least one configuration information about the MRB is available and the UE has joined the multicast MBS session, identifying whether the multicast MBS session is activated; and In case the multicast MBS session is activated, the multicast MBS session is received in the RRC inactive state.

6. A method for multicast and broadcast service (MBS) in a wireless communication system performed by a base station, the method comprising: sending a radio resource control (RRC) reconfiguration message to a user equipment (UE), the RRC reconfiguration message configuring the UE to perform multicast MBS reception in an RRC inactive state; sending an RRC release message including at least one configuration information about a multicast MBS radio bearer (MRB) to the UE; as well as Send multicast MBS session to UE, wherein the at least one configuration information about the multicast MRB is stored in an RRC inactive state, and The multicast MBS session associated with the RRC inactive state is based on the at least one stored configuration information.

7. The method according to claim 6, in, The at least one configuration information about the MRB includes point-to-multipoint (PTM) configuration information for one or more multicast MBS sessions, where the same physical downlink control channel (PDCCH) resources can be used by both connected UEs and inactive UEs for the same multicast MBS session, wherein the same physical downlink shared channel (PDSCH) resources can be used by both connected UEs and inactive UEs for the same multicast MBS session, and The multicast MBS session is based on whether the at least one configuration information about the MRB is available, whether the UE has joined the multicast MBS session, and whether the multicast MBS session is activated.

8. The method according to claim 6, further comprising: A group paging message is sent to the UE, wherein the group paging message includes at least one of the following: first information about activation of a multicast MBS session, second information about changing the at least one configuration information about the MRB, third information about whether to receive the multicast MBS session in an RRC inactive state, and fourth information about switching the UE from the RRC inactive state to the RRC connected state.

9. A user equipment (UE) for a multicast and broadcast service (MBS) in a wireless communication system, the UE comprising: Transceiver; and The controller is configured as: In a radio resource control (RRC) connected state, receiving a radio resource control (RRC) reconfiguration message from a base station, the RRC reconfiguration message configuring the UE to perform multicast MBS reception in an RRC inactive state, receiving, from a base station, an RRC release message including at least one configuration information about a multicast MBS radio bearer (MRB), In an RRC inactive state, storing the at least one configuration information about the multicast MRB; The multicast MBS session is received in the RRC inactive state based on the at least one stored configuration information.

10. The UE according to claim 9, in, The at least one configuration information about the MRB includes point-to-multipoint (PTM) configuration information for one or more multicast MBS sessions, wherein the same physical downlink control channel (PDCCH) resources can be used by both connected UEs and inactive UEs for the same multicast MBS session, and Therein, the same Physical Downlink Shared Channel (PDSCH) resources can be used by both connected UEs and inactive UEs for the same multicast MBS session.

11. The UE according to claim 9, wherein: The controller is also configured to: A group paging message is received from a base station, wherein the group paging message includes at least one of: first information about activation of a multicast MBS session, second information about changing the at least one configuration information about the MRB, third information about whether the multicast MBS session is received in an RRC inactive state, and fourth information about switching the UE from the RRC inactive state to the RRC connected state.

12. The UE according to claim 9, wherein: The controller is also configured to: determining whether the at least one configuration information about the MRB is available and whether the UE has joined the multicast MBS session, In case the at least one configuration information about the MRB is available and the UE has joined the multicast MBS session, determining whether the multicast MBS session is activated, and In case the multicast MBS session is activated, the multicast MBS session is received in the RRC inactive state.

13. A base station for a multicast and broadcast service (MBS) in a wireless communication system, the base station comprising: Transceiver; and The controller is configured as: sending a radio resource control (RRC) reconfiguration message to a user equipment (UE), the RRC reconfiguration message configuring the UE to perform multicast MBS reception in an RRC inactive state, sending an RRC release message including at least one configuration information about a multicast MBS radio bearer (MRB) to the UE, and Send multicast MBS session to UE, wherein the at least one configuration information about the multicast MRB is stored in an RRC inactive state, and The multicast MBS session associated with the RRC inactive state is based on the at least one stored configuration information.

14. The base station according to claim 13, in, The at least one configuration information about the MRB includes point-to-multipoint (PTM) configuration information for one or more multicast MBS sessions, where the same physical downlink control channel (PDCCH) resources can be used by both connected UEs and inactive UEs for the same multicast MBS session, wherein the same physical downlink shared channel (PDSCH) resources can be used by both connected UEs and inactive UEs for the same multicast MBS session, and The multicast MBS session is based on whether the at least one configuration information about the MRB is available, whether the UE has joined the multicast MBS session, and whether the multicast MBS session is activated.

15. The base station according to claim 13, wherein: The controller is also configured to: A group paging message is sent to the UE, wherein the group paging message includes at least one of the following: first information about activation of a multicast MBS session, second information about changing the at least one configuration information about the MRB, third information about whether to receive the multicast MBS session in an RRC inactive state, and fourth information about switching the UE from the RRC inactive state to the RRC connected state.

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