System and method for managing mobility of multicast UE in a wireless network

Abstract

The present disclosure relates to a 5G or 6G communication system for supporting a higher data transmission rate. Embodiments herein disclose a method for handling multicast reception in a network (1000) by a UE (100). The method includes determining multicast reception to be received in an RRC inactive state when the UE is in a mobility scenario. Further, the method comprises receiving, from the network device (200), a message supporting a mobility scenario of the UE in the RRC inactive state. Further, the method includes handling multicast reception of the UE in the mobility scenario based on the message.

Description

Technical Field

[0001] Embodiments disclosed herein relate to wireless communication networks, and more particularly, to systems and methods for managing mobility of user equipment (UE) receiving a New Radio Multicast Broadcast Service (NR MBS) multicast service. Background Art

[0002] 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 "below 6 GHz" frequency bands such as 3.5 GHz, but also in "above 6 GHz" frequency bands called mmWave including 28 GHz and 39 GHz. In addition, it has been considered to implement 6G mobile communication technology (called super 5G system) in terahertz frequency bands (e.g., 95 GHz to 3 THz frequency bands) in order to achieve 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 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 low latency communications (URLLC), and massive machine type communications (mMTC), there has been ongoing standardization on beamforming and massive MIMO for mitigating radio wave path loss and increasing radio wave transmission distance in mmWave, parameter sets to support dynamic operation for efficient utilization of mmWave resources and time slot formats (e.g., operating multiple subcarrier spacings), initial access technology for supporting multi-beam transmission and broadband, definition and operation of BWP (Bandwidth Part) new channel coding methods such as LDPC (Low Density Parity Check) codes for large amounts of data transmission and polar codes for highly reliable transmission of control information, L2 pre-processing, and network slicing for providing dedicated networks dedicated to specific services.

[0004] Currently, in view of the services that 5G mobile communication technology is to support, there are ongoing discussions on improvements and performance enhancements of initial 5G mobile communication technology, and there has been physical layer standardization on technologies such as V2X (Vehicle to Everything) for assisting driving determination of autonomous vehicles based on information on the location and status of the vehicle sent by the vehicle and for enhancing user convenience, NR-U (New Radio Unlicensed) for system operation in compliance with various regulatory-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 addition, there has been ongoing standardization on air interface architecture / protocols for technologies such as Industrial Internet of Things (IIoT) for supporting new services through interworking and convergence with other industries, IAB (Integrated Access and Backhaul) for providing nodes for network service area expansion by supporting wireless backhaul links and access links in an integrated manner, mobility enhancements including conditional handover and DAPS (Dual Active Protocol Stack) handover, and two-step random access (NR's two-step RACH) for simplifying the random access procedure. There is also ongoing standardization on system architecture / services for 5G baseline architecture (e.g., service-based architecture or service-based interface) for combining network function 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 already exponentially growing number of connected devices will be connected to the communication network, and it is accordingly expected that enhanced functionality and performance of the 5G mobile communication systems and integrated operations of the connected devices will be necessary. To this end, new research related to extended reality (XR) is arranged for effectively supporting AR (augmented reality), VR (virtual reality), MR (mixed reality), etc., improving 5G performance and reducing complexity by utilizing artificial intelligence (AI) and machine learning (ML), AI service support, metaverse service support, and drone communication.

[0007] Furthermore, such development of 5G mobile communication systems will serve as a foundation for developing not only new waveforms for providing terahertz band coverage 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 technologies using OAM (orbital angular momentum), and high-dimensional spatial multiplexing technologies of RIS (reconfigurable smart surface), but also full-duplex technologies for improving frequency efficiency of 6G mobile communication technology and improving system networks, AI-based communication technologies for achieving system optimization and internalizing end-to-end AI support functions by utilizing satellites and AI (artificial intelligence) from the design stage, and next-generation distributed computing technologies for achieving services that exceed the level of complexity that UEs can achieve by utilizing ultra-high-performance communication and computing resources to limit the limitations of UE operating capabilities.

[0008] The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with respect to the present disclosure. Summary of the invention

[0009] Technical issues

[0010] Embodiments herein provide a method and system for managing the mobility of a UE receiving an MBS multicast service (e.g., an NR MBS multicast service), wherein the UE may receive the multicast service in an RRC_INACTIVE state, thereby ensuring reliable and efficient multicast service continuity in a wireless network.

[0011] Solution to the problem

[0012] Therefore, an embodiment of the present invention provides a method for processing multicast reception in a wireless network. The method includes determining, by the UE when the UE is in a mobility scenario, the multicast reception to be received in a radio resource control (RRC) inactive state. In addition, the method includes receiving, by the UE from a network device, at least one message that supports the mobility scenario of the UE in the RRC inactive state. The at least one message includes at least one of the following: multicast service coverage information for supporting the mobility of the UE, a multicast inclusion list for cell reselection of the multicast service, a multicast exclusion list for cell reselection of the multicast service, a list of neighboring cell information, applicability information of the multicast configuration of the service cell for at least one neighboring cell, a neighboring cell multicast configuration, a cell state indication for multicast reception, a cell reservation indication for multicast reception, a cell reselection priority, and a priority of the frequency for cell reselection. In addition, the method includes processing the multicast reception of the UE in the mobility scenario by the UE based on the at least one message received.

[0013] In an embodiment, the at least one multicast service coverage information includes at least one of a neighbor cell list of the serving cell and a frequency supporting the multicast service. The at least one multicast service coverage information is provided via at least one of an RRC reconfiguration message carrying an MBS radio bearer (MRB) configuration for the multicast service, an RRC release message with suspendconfig carrying an MRB configuration for multicast service reception, a system information broadcast (SIB), and an MBS control channel (MCCH) signaling.

[0014] In an embodiment, when the UE is interested in receiving multicast services in the RRC inactive state, the UE does not consider cells in the multicast exclusion list as candidate cells for cell reselection.

[0015] In an embodiment, when the UE is interested in receiving a multicast service in an RRC inactive state, the UE considers at least one cell in the multicast inclusion list as a candidate cell for cell reselection.

[0016] In an embodiment, at least one of the cell status indication and the cell reservation indication includes at least one of a multicastCellBarred field, a multicastCellBarred-inactive field, a multicastSupport field, and a multicastSupport-inactive field. The multicastCellBarred field and the multicastCellBarred-inactive field indicate whether the cell is prohibited from being used for multicast reception in an RRC inactive state. The multicastSupport field and the multicastSupport-inactive field indicate whether multicast reception is supported in an RRC inactive state. The cell status indication for multicast reception and the cell reservation indication for multicast reception are received in at least one of a MIB message, a SIB1 message, an MBS SIB message, and an MCCH message.

[0017] In an embodiment, processing of the UE's multicast reception based on the received message includes reselecting a cell in a notification area (RNA) or a multicast coverage area based on a radio access network, and continuing multicast reception in the cell based on receiving an indication from a network device of all neighboring cells in the RNA or the multicast coverage area that include multicast MBS radio bearer (MRB) configuration information that is exactly the same as the multicast MBS radio bearer (MRB) configuration information of the serving cell through at least one message including at least one neighboring cell multicast configuration.

[0018] In an embodiment, processing of multicast reception of a UE in a mobility scenario by the UE based on received messages includes prioritizing cells, and reselecting cells in the RNA or multicast coverage area and continuing multicast reception in the cells based on receiving an indication of a neighboring cell in an RNA or multicast coverage area from a network device through at least one message including at least one neighboring cell multicast configuration, the neighboring cell including multicast MRB information that is exactly the same as the multicast MRB information of the serving cell.

[0019] In an embodiment, the UE processes the UE's multicast reception based on the received message, including: prioritizing cells and reselecting cells that provide multicast services of interest to the UE based on an indication received from a network device about all neighboring cells in an RNA or multicast coverage area that include multicast MRB information different from the multicast MRB information of a serving cell through at least one message including at least one neighboring cell multicast configuration.

[0020] In an embodiment, when the UE is configured to receive multicast communications in the RRC inactive state, the UE considers the frequency providing or supporting the multicast communications as the highest priority when performing cell reselection.

[0021] In an embodiment, the UE prioritizes at least one of neighboring cells and frequencies for cell reselection based on at least one of: the strongest cell belonging to the highest reselection priority frequency, the ranking of the cell, the signal strength of the cell, support for prioritized multicast sessions on the cell, the status of multicast session support on the cell for the UE, and support for a maximum number of related multicast sessions on the cell for the UE.

[0022] In an embodiment, when the selected cell or frequency does not support a multicast session, the UE re-derives the reselection priority of the frequency by considering the multicast sessions supported by the cell.

[0023] In an embodiment, the UE determines the priority of frequencies for cell reselection based on at least one of a broadcast signaling message, a dedicated signaling message, a cell reselection priority message, and a multicast cell reselection priority message received from a network device.

[0024] In an embodiment, the UE derives a reselection priority for cell reselection, while the UE is configured to receive at least one multicast session in an RRC inactive state based on at least one of the following: a frequency supporting at least one multicast session has a higher reselection priority than another frequency not supporting the multicast session, the frequency being determined based on the cell reselection priority and a request for reduced priority for multicast, the frequency supporting at least one multicast session prioritized based on critical services, wherein the critical services include at least one of the following: public safety services, mission critical push-to-talk (MCPTT) services.

[0025] In an embodiment, processing, by the UE, multicast reception of the UE in a mobility scenario based on the received at least one message includes: indicating interest to a network device upon determining that the UE performs cell reselection for a cell, wherein the cell does not provide at least one activated multicast service in which the UE is receiving. The indication is provided by at least one of an MBS interest indication message, a UE assistance information message, a short message, and a pre-configured random access preamble. After the UE transitions from an RRC inactive state to an RRC connected state, indicating interest to the network device.

[0026] In an embodiment, processing, by the UE, multicast reception of a UE in a mobility scenario based on at least one received message includes performing at least one of the following: continuing to listen to group paging or notification (e.g., via a paging message or an MCCH message) for activating or deactivating at least one multicast session, and receiving at least one multicast session on a reselected cell, and when the UE performs reselection to a neighboring cell, using neighboring cell information to determine support for the multicast session and configuration of the multicast session on the reselected cell.

[0027] In an embodiment, processing, by the UE, multicast reception of the UE in a mobility scenario based on the received at least one message includes at least one of: stopping or reducing the priority of cell reselection to a cell or frequency that does not support at least one multicast session, and transitioning to an RRC connected state when cell reselection to a cell or frequency does not support at least one multicast session that the UE is interested in. In addition, the UE stops listening to group paging or notifications.

[0028] In an embodiment, cell reselection of a UE interested in receiving multicast in an RRC inactive state is triggered when at least one of a performance trigger condition, a change in broadcast signaling for cell reselection, a change in multicast session, a change in MRB information, a change in priority reduction, and a change in congestion status information is met.

[0029] Therefore, embodiments of the present invention provide a method for processing multicast reception in a wireless network. The method includes receiving an RRC release with a suspended configuration by a UE. In addition, the method includes receiving a priority reduction request for the multicast configuration by the UE. In addition, the method includes storing the priority reduction request for the multicast configuration by the UE. In addition, the method includes starting a timer by the UE. In addition, the method includes maintaining the priority reduction request for the multicast configuration by the UE until the timer expires or a release of the priority reduction request for the multicast configuration is received. In addition, the method includes performing cell reselection by the UE under RRC non-activation. In addition, the method includes treating the current frequency or the frequency indicated in the stored priority reduction request for the multicast configuration as the lowest priority.

[0030] Therefore, an embodiment of the present invention provides a method for processing multicast reception in a wireless network. The method includes sending, by a network device, at least one message to a UE that supports a mobility scenario of a UE in an RRC inactive state. The at least one message includes at least one of the following: multicast service coverage information for supporting the mobility of the UE, a multicast inclusion list for cell reselection of a multicast service, a multicast exclusion list for cell reselection of a multicast service, a list of neighboring cell information, applicability information of a multicast configuration of a service cell for at least one neighboring cell, a neighboring cell multicast configuration, a cell status indication for multicast reception, a cell reservation indication for multicast reception, a cell reselection priority, and a priority of a frequency for cell reselection. In addition, the method includes processing the multicast reception of the UE by the network device based on at least one message.

[0031] Therefore, an embodiment of the present invention provides a UE including an MBS multicast service controller coupled to a processor and a memory. The MBS multicast service controller is configured to determine the multicast reception to be received in an RRC inactive state when the UE is in a mobility scenario. Further, the MBS multicast service controller is configured to receive at least one message supporting the mobility scenario of the UE in the RRC inactive state from a network device. The at least one message includes at least one of the following: multicast service coverage information for supporting the mobility of the UE, a multicast inclusion list for cell reselection of the multicast service, a multicast exclusion list for cell reselection of the multicast service, a list of neighboring cell information, applicability information of the multicast configuration of the service cell for at least one neighboring cell, neighboring cell multicast configuration, cell status indication for multicast reception, cell reservation indication for multicast reception, cell reselection priority, and priority of frequency for cell reselection. In addition, the MBS multicast service controller is configured to process the multicast reception of the UE based on the at least one message received.

[0032] Therefore, an embodiment of the present invention provides a UE, which includes an MBS multicast service controller coupled to a processor and a memory. The MBS multicast service controller is configured to receive an RRC release with a suspended configuration. In addition, the MBS multicast service controller is configured to receive a priority reduction request for the multicast configuration. In addition, the MBS multicast service controller is configured to store the priority reduction request for the multicast configuration. In addition, the MBS multicast service controller is configured to start a timer and maintain the priority reduction request for the multicast configuration until the timer expires or the release of the priority reduction request for the multicast configuration is received. In addition, the MBS multicast service controller is configured to perform cell reselection under RRC inactivity. In addition, the MBS multicast service controller is configured to regard the current frequency or the frequency indicated in the stored priority reduction request for the multicast configuration as the lowest priority.

[0033] Therefore, an embodiment of the present invention provides a network device, which includes an MBS multicast service controller coupled to a processor and a memory. The MBS multicast service controller is configured to send at least one message to a UE to support a mobility scenario of a UE in an RRC inactive state. The at least one message includes at least one of the following: multicast service coverage information for supporting the mobility of the UE, a multicast inclusion list for cell reselection of a multicast service, a multicast exclusion list for cell reselection of a multicast service, a list of neighboring cell information, applicability information of a multicast configuration of a service cell for at least one neighboring cell, a neighboring cell multicast configuration, a cell status indication for multicast reception, a cell reservation indication for multicast reception, a cell reselection priority, and a priority of a frequency for cell reselection. In addition, the MBS multicast service controller is configured to process the UE's multicast reception based on the at least one message.

[0034] According to an embodiment, a method performed by a user equipment (UE) in a communication system may be provided.

[0035] According to an embodiment, the method may include identifying frequency information associated with multicast broadcast service (MBS) service continuity in a radio resource control (RRC) inactive state.

[0036] According to an embodiment, the method may include performing cell reselection based on the frequency information.

[0037] According to an embodiment, the method may include identifying whether a reselected cell through cell reselection is available for MBS multicast reception.

[0038] According to an embodiment, the method may include: in a case where the reselected cell is available for MBS multicast reception: receiving the MBS multicast reception from the reselected cell in an RRC inactive state.

[0039] According to an embodiment, the method may include: in a case where the reselected cell is not available for MBS multicast reception: transitioning to an RRC connected state; and receiving the MBS multicast reception in the RRC connected state.

[0040] According to an embodiment, the MBS multicast reception may be an MBS multicast reception to be received by the UE or to be continued to be received by the UE.

[0041] According to an embodiment, the frequency information may include frequency prioritization for MBS multicast reception.

[0042] According to an embodiment, the frequency information may include a first frequency list and a second frequency list, wherein MBS multicast is available on the first frequency list and MBS multicast is not available on the second frequency list.

[0043] According to an embodiment, the reselected cell may correspond to a frequency included in the first list.

[0044] According to an embodiment, the frequency information may be obtained via broadcast signaling or dedicated signaling.

[0045] According to an embodiment, a user equipment (UE) in a communication system may be provided.

[0046] According to an embodiment, the UE may include a transceiver; and a processor coupled with the transceiver.

[0047] According to an embodiment, the processor may be configured to identify frequency information associated with multicast broadcast service (MBS) service continuity in a radio resource control (RRC) inactive state.

[0048] According to an embodiment, the processor may be configured to perform cell reselection based on frequency information.

[0049] According to an embodiment, the processor may be configured to identify whether a reselected cell through cell reselection is available for MBS multicast reception.

[0050] According to an embodiment, the processor may be further configured to: if the reselected cell is available for MBS multicast reception: receive the MBS multicast reception from the reselected cell in an RRC inactive state.

[0051] According to an embodiment, the processor may be further configured to: transition to an RRC connected state; and receive the MBS multicast reception in the RRC connected state if the reselected cell is not available for the MBS multicast reception.

[0052] According to an embodiment, the MBS multicast reception may be an MBS multicast reception to be received by the UE or to be continued to be received by the UE.

[0053] According to an embodiment, the frequency information may include frequency prioritization for MBS multicast reception.

[0054] According to an embodiment, the frequency information may include a first frequency list and a second frequency list, wherein MBS multicast is available on the first frequency list and MBS multicast is not available on the second frequency list.

[0055] According to an embodiment, the reselected cell may correspond to a frequency included in the first list.

[0056] According to an embodiment, a method performed by a base station in a communication system may be provided.

[0057] According to an embodiment, the method may include sending information associated with the frequency information to a user equipment (UE).

[0058] According to an embodiment, frequency information may be associated with multicast broadcast service (MBS) service continuity in a radio resource control (RRC) inactive state.

[0059] According to an embodiment, the method may include: in a case where the cell associated with the frequency information is available for MBS multicast transmission, providing MBS multicast transmission to the UE in the RRC inactive state on the cell.

[0060] According to an embodiment, a base station in a communication system may be provided.

[0061] According to an embodiment, the base station may include a transceiver; and a processor coupled with the transceiver.

[0062] According to an embodiment, the processor may be configured to send information associated with frequency information to a user equipment (UE).

[0063] According to an embodiment, frequency information may be associated with multicast broadcast service (MBS) service continuity in a radio resource control (RRC) inactive state.

[0064] According to an embodiment, the processor may be configured to: in a case where the cell associated with the frequency information is available for MBS multicast transmission, provide MBS multicast transmission to the UE in the RRC inactive state on the cell.

[0065] When considered in conjunction with the following description and the accompanying drawings, these and other aspects of the embodiments herein will be better appreciated and understood. However, it should be understood that the following description, although indicating at least one embodiment and many specific details thereof, is provided by way of illustration and not limitation. Without departing from the spirit of this article, many changes and modifications may be made within the scope of the embodiments herein, and the embodiments herein include all such modifications.

[0066] Advantageous Effects of the Invention

[0067] According to an embodiment, a method and system for managing the mobility of a UE receiving an MBS multicast service (e.g., an NR MBS multicast service) can be provided, wherein the UE can receive the multicast service in an RRC_INACTIVE state, thereby ensuring reliable and effective multicast service continuity in a wireless network. BRIEF DESCRIPTION OF THE DRAWINGS

[0068] The embodiments disclosed herein are shown in the accompanying drawings, and the same reference numerals indicate corresponding parts in the various drawings throughout the drawings. The embodiments of the present invention will be better understood from the following description with reference to the accompanying drawings, wherein:

[0069] Figure 1A wireless network for handling multicast reception in an RRC inactive state according to embodiments disclosed herein is shown;

[0070] Figure 2 Various hardware components of a UE according to the embodiments disclosed herein are shown;

[0071] Figure 3 Various hardware components of a network device according to embodiments disclosed herein are shown;

[0072] Figure 4 is a flowchart illustrating a method implemented by a UE for processing multicast reception in an RRC inactive state in a wireless network according to an embodiment disclosed herein;

[0073] Figure 5 is a flowchart depicting a method implemented by a UE for enabling the UE to perform cell reselection in an RRC inactive state in a wireless network according to an embodiment disclosed herein;

[0074] Figure 6 is a flowchart showing a method implemented by a network device for processing multicast reception in an RRC inactive state in a wireless network according to an embodiment disclosed herein; and

[0075] Figure 7 is an example flow chart illustrating a method for managing the mobility of a UE receiving NR MBS multicast service in an RRC inactive state according to an embodiment disclosed herein.

[0076] Figure 8 An electronic device according to an embodiment of the present disclosure is shown.

[0077] Fig. 9 A base station according to various embodiments of the present disclosure is shown. DETAILED DESCRIPTION

[0078] The embodiments of this invention and their various features and advantageous details are explained more fully with reference to the non-limiting embodiments shown in the accompanying drawings and described in detail in the following description. The description of known components and processing techniques is omitted so as not to unnecessarily obscure the embodiments of this invention. The examples used herein are only intended to facilitate understanding of the manner in which the embodiments of this invention can be practiced, and further enable those skilled in the art to practice the embodiments of this invention. Therefore, the examples should not be interpreted as limiting the scope of the embodiments of this invention.

[0079] NR MBS services may refer to multicast services, where the intended common content is targeted to a group of user equipment (UE) that have joined a multicast group in a multicast coverage area, and broadcast services, where the intended content may be targeted to all UEs in a broadcast coverage area. The coverage area may be one radio cell or larger. In a conventional system (i.e., 3rd Generation Partnership Project (3GPP) Release 17 MBS), UEs receive multicast services only in the RRC_CONNECTED state. However, there may also be UEs that can receive multicast sessions in the RRC_INACTIVE state (e.g., 3GPP Release 18 MBS may consider such a scenario).

[0080] A potential problem involves UEs that are able to receive MBS multicast services in the RRC_INACTIVE state. In certain scenarios, for example, a UE in the RRC_INACTIVE state may perform mobility (e.g., cell reselection) and may leave the coverage of the multicast service. That is, the UE may suffer service interruption due to mobility, and there is no clear mechanism to ensure multicast service maintenance and continuity as well as the mobility of the UE.

[0081] It would be desirable to address the above-mentioned or other disadvantages or at least provide a useful alternative.

[0082] Embodiments of the present invention implement a method for processing multicast reception in a wireless network. The method includes determining, by the UE, multicast reception to be received in an RRC inactive state when the UE is in a mobility scenario. In addition, the method includes receiving, by the UE, from a network device at least one message that supports a mobility scenario of the UE in an RRC inactive state. The at least one message includes at least one of the following: multicast service coverage information supporting the mobility of the UE; a multicast inclusion list for cell reselection of the multicast service; a multicast exclusion list for cell reselection of the multicast service; a list of neighboring cell information (e.g., the neighboring cell information may include a bit, a bitmap, or a field indicating the availability or unavailability of at least one MBS session of the serving cell for at least one neighboring cell); applicability information of a multicast configuration of a serving cell for at least one neighboring cell (e.g., the neighboring cell information may include a bit, a bitmap, or a field indicating the applicability or unapplicability of a multicast configuration of at least one MBS session of the serving cell for at least one neighboring cell), a neighboring cell multicast configuration, a cell state indication for multicast reception, a cell reservation indication for multicast reception, a cell reselection priority, and a priority of a frequency for cell reselection. Furthermore, the method includes processing, by the UE, multicast reception of the UE in the mobility scenario based on the received at least one message.

[0083] In an embodiment, when the list of neighbor cell information does not exist, the UE interprets that multicast session reception is not available on the neighbor cell. In an alternative embodiment, when the list of neighbor cell information does not exist, the UE interprets that multicast session reception is available on the neighbor cell. In an alternative embodiment, when the list of neighbor cell information does not exist, the UE does not interpret anything about the availability or unavailability of the multicast session on the neighbor cell.

[0084] In an embodiment, the neighbor cell may be indicated by a physical cell identity field and / or a carrier frequency field. In the absence of the carrier frequency field, the frequency is considered to be the same frequency of the serving cell that provides neighbor cell information to the UE in the RRC release with suspendConfig or in the multicast MCCH message.

[0085] In an embodiment, the UE checks the SIB1 and / or multicast MCCH on the selected neighboring cell or the reselected cell and determines whether a multicast session is provided on the cell. If the selected cell or the reselected cell does not provide the configuration of the multicast session that the UE is interested in receiving in the multicast MCCH message, the UE resumes the RRC connection to utilize the multicast MBS radio bearer configuration and receive the multicast session.

[0086] In an embodiment, the UE prioritizes and considers serving cells that provide point-to-multipoint (PTM) configuration to the UE in RRC release with suspendConfig for cell selection / reselection, for example, when transitioning from RRC_CONNECTED state to RRC_INATIVE state.

[0087] In an embodiment, the UE prioritizes and considers a serving cell that provides a PTM configuration to the UE in an RRC release with suspendConfig and / or at least one neighbor cell that is included in the neighbor cell information and provides a multicast session that the UE is interested in and / or is configured to receive in the RRC_INACTIVE state, for cell selection / reselection (e.g.) when transitioning from the RRC_CONNECTED state to the RRC_INATIVE state.

[0088] In an embodiment, the UE prioritizes a serving cell that provides a PTM configuration to the UE in an RRC release with suspendConfig and / or at least one neighbor cell that is included in the neighbor cell information and has the same multicast MRB configuration as the serving cell that provides the PTM configuration to the UE in the RRC release with suspendConfig, for cell selection / reselection, e.g., when transitioning from the RRC_CONNECTED state to the RRC_INATIVE state.

[0089] The method can be used to manage the mobility of UEs receiving NR MBS multicast services, where the UEs can receive the multicast services in an RRC inactive state. The method can be used to ensure the maintenance and continuity of the multicast services and the mobility of the UEs in the RRC inactive state.

[0090] Referring now to the drawings, and more particularly to Figures 1 to 7 , wherein like reference numerals consistently represent corresponding features throughout the drawings, at least one embodiment is shown.

[0091] Figure 1 A wireless network (1000) for processing multicast reception in an RRC inactive state according to an embodiment disclosed herein is shown. The wireless network (1000) may be, for example but not limited to, a fourth generation (4G) network, a fifth generation (5G) network, an open radio access network (ORAN), etc.

[0092] In an embodiment, a wireless network (1000) includes a UE (100) and a network device (200). The UE (100) may be, for example, but not limited to, a laptop, a smartphone, a desktop computer, a notebook, a device-to-device (D2D) device, a vehicle-to-everything (V2X) device, a foldable phone, a smart TV, a tablet, an immersive device, and an Internet of Things (IoT) device. The network device (200) may be, for example, but not limited to, a gNB, an eNB, a new radio (NR) transceiver, etc.

[0093] When the UE (100) is in a mobility scenario, the UE (100) determines a multicast reception to be received in an RRC inactive state. In addition, the UE (100) receives a message supporting a mobility scenario of the UE (100) in an RRC inactive state from a network device (200). The message may be, for example, but not limited to, multicast service coverage information supporting the mobility of the UE (100), a multicast inclusion list for cell reselection of a multicast service, a multicast exclusion list for cell reselection of a multicast service, a list of neighboring cell information, applicability information of a multicast configuration of a serving cell for at least one neighboring cell, a neighboring cell multicast configuration, a cell status indication for multicast reception, a cell reservation indication for multicast reception, a cell reselection priority, and a priority of a frequency for cell reselection. Based on the received message, the UE (100) processes the multicast reception of the UE (100). The processing of the multicast reception of the UE (100) is described below.

[0094] Specifically, UEs (100) supporting 3GPP Release 18 MBS are capable and / or configured to receive multicast in the RRC_INACTIVE state, while UEs (100) related to previous releases (i.e., 3GPP Release 17 MBS) may not be capable and / or not configured to receive multicast in the RRC_INACTIVE state. Coexistence of these two groups of UEs (100) in the same cell / network is feasible and needs to be supported. In addition, mechanisms are needed to ensure the maintenance and continuity of multicast services in the RRC_INACTIVE state and the mobility of the UEs (100).

[0095] In an embodiment, a network device (e.g., gNB, etc.) (200) provides one or more multicast service coverage information to a UE (100) to support the mobility of a UE (100) in an RRC_INACTIVE state. The information may be a list of neighboring cells of a serving cell and / or a frequency supporting the same multicast service. The information is provided by at least one of an RRC reconfiguration message carrying an MBS radio bearer (MRB) configuration for a multicast service or an RRC release with suspendconfig carrying an MRB configuration for multicast service reception in an RRC_INACTIVE state, or a broadcast signaling method in an RRC_INACTIVE state (e.g., a system information broadcast (SIB) or an MBS control channel (MCCH) delivering the information).

[0096] In an embodiment, the network device (200) provides a multicast inclusion list (or whitelisted cells) and / or a multicast exclusion list (or blacklisted cells) to a UE (100) for cell reselection for multicast reception in the RRC_INACTIVE state. When the UE (100) is interested in and / or is receiving multicast in the RRC_INACTIVE state, the UE (100) does not consider any cell in the multicast exclusion list as a candidate for cell reselection. When the UE (100) is interested in and / or is receiving multicast in the RRC_INACTIVE state, the UE (100) only considers cells in the multicast inclusion list as candidates for cell reselection.

[0097] In an embodiment, the network device (200) provides the UE (100) with cell status and cell reservation indications for multicast reception in one of the MIB or SIB (e.g., SIB1 or MBS SIB) or MCCH messages. These indications may include a field "multicastCellBarred" (or "multicastCellBarred-Inactive"), which may indicate that the cell is prohibited or the cell is not prohibited for multicast reception (or multicast reception under RRC_INACTIVE). This field is only applicable to UEs (100) that are interested in receiving and / or receiving multicast services (or UEs (100) that are interested in and / or receiving multicast services under RRC_INACTIVE). If the cell status multicastCellBarred is prohibited, the UE (100) can exclude the prohibited cell as a candidate for cell selection and / or reselection (e.g., for 300 seconds), and if the reselection criteria are met, the UE (100) can select another cell on the same frequency.

[0098] In an embodiment, the network device (200) provides the UE (100) with cell status and cell reservation indications for multicast reception in one of the MIB or SIB (e.g., SIB1 or MBS SIB) or MCCH messages. These indications may include a field "multicastSupport" (or "multicastSupport-Inactive"), which may indicate whether multicast is supported (or whether multicast is supported under RRC_INACTIVE). This field is only applicable to UEs (100) that are interested in receiving and / or receiving multicast services (or UEs (100) that are interested in and / or receiving multicast services under RRC_INACTIVE). If the field is provided in SIB1, the field may also be provided per PLMN (or per SNPN). If the cell status multicastSupport is true, the UE (100) considers the cell as a candidate for cell selection and / or reselection.

[0099] In an embodiment, the network device (200) provides multicast configuration of neighboring cells for UE (100) moving to other cells in the same radio access network-based notification area (RNA) or multicast coverage area. This may involve one or more options as described below:

[0100] a) All neighboring cells in RNA have exactly the same multicast MRB information: the network device (e.g., gNB, etc.) indicates it. Based on the multicast MRB information, the UE (100) reselects any cell in RNA and continues multicast reception.

[0101] b) Neighboring cells have exactly the same multicast MRB information: The network device (e.g., gNB) can indicate neighboring cells. The UE (100) can prioritize the cells. Based on the indication, the UE (100) reselects the cells and continues multicast reception.

[0102] c) Neighboring cells have different multicast MRB information: The gNB may provide the MRB configuration of neighboring cells. Based on the MRB configuration of neighboring cells, the UE (100) may prioritize the cells providing the multicast service that the UE (100) is interested in.

[0103] d) Neighboring cell does not provide multicast MRB information that the UE (100) is interested in: When the UE (100) reselects a cell, the UE (100) must enter RRC_CONNECTED. It can be based on group paging or on its own. In addition, the UE (100) needs to indicate to the gNB that the UE (100) is interested in multicast services.

[0104] In an embodiment, when the UE (100) performs cell reselection for a cell that does not provide "all" activated multicast services that the UE (100) is receiving, the UE (100) indicates its interest to the network device (200). The indication may be an MBS interest indication message or a UE assistance information message or a short message or a pre-configured random access preamble. The UE (100) may transition to the RRC_CONNECTED state in order to send the indication.

[0105] In another embodiment, when the UE (100) performs cell reselection for a cell that does not provide "any" activated multicast service that the UE (100) is receiving, the UE (100) indicates its interest to the network device (200). The indication may be an MBS interest indication message or a UE assistance information message or a short message or a pre-configured random access preamble. The UE (100) may transition to the RRC_CONNECTED state in order to send the indication.

[0106] In an embodiment, a UE (100) in an RRC_INACTIVE state may cause at least one multicast session to be in a deactivated state (i.e., the UE (100) may listen to group paging or notifications of "activation" of a multicast session) and / or at least one multicast session to be in an activated state (i.e., the UE (100) is receiving a multicast session and may listen to group paging or notifications of "deactivation" of a multicast session). The group paging or notification may be provided via a paging message or an MCCH message. When the UE (100) performs reselection to a neighboring cell, the UE (100) continues to listen to the group paging or notifications to activate or deactivate the multicast session and / or receives the multicast session on the reselected cell based on the deactivation or activation state of the multicast session, provided that the given neighboring cell information of the network conveys support for the multicast session and / or configuration of the multicast session.

[0107] In an embodiment, when the UE (100) is configured to receive multicast communications in the RRC_INACTIVE state, the UE (100) may consider a frequency providing multicast communications configuration as the highest priority when performing cell reselection.

[0108] In an embodiment, the UE (100) performs prioritization between neighboring cells and / or frequencies for cell reselection based on at least one of the following factors:

[0109] a) The strongest cell belonging to the highest reselection priority frequency.

[0110] b) Ranking of cells and / or signal strength of cells.

[0111] c) Support for prioritized multicast sessions on a cell.

[0112] d) The state of multicast session support on the cell for the UE (100) (eg, activation or deactivation state).

[0113] e) Support for a maximum number of related multicast sessions on a cell for a UE (100).

[0114] In an embodiment, for a UE (100) configured to and / or receiving one or more multicast sessions in RRC_INACTIVE state and performing cell reselection if the best cell in a frequency satisfies the "S" criterion for cell reselection based on frequency reselection priorities but the cell does not support one or more or all multicast sessions, the UE (100) should re-derive the reselection priorities for the frequency by considering the multicast sessions supported by the cell (rather than the multicast sessions corresponding to the NR frequency). The reselection priorities are used for a maximum of 300 seconds, or until new information about the multicast sessions is received (e.g., release of the multicast sessions) and / or a change in the UE's interest in the multicast sessions is received. The UE (100) should ensure that the above cell reselection criteria are met based on the newly derived priorities.

[0115] In an embodiment, the UE (100) derives a reselection priority for cell reselection while the UE (100) is configured to and / or is receiving a multicast session in the RRC_INACTIVE state according to at least one of the following rules:

[0116] a) A frequency supporting at least one multicast session that the UE (100) is interested in and / or is receiving in RRC_INACTIVE state has a higher reselection priority than a frequency not supporting any of the multicast sessions that the UE (100) is interested in and / or is receiving in RRC_INACTIVE state.

[0117] b) frequencies supporting at least one multicast session of interest to the UE (100) and / or being received in the RRC_INACTIVE state are prioritized in order of at least one of their priority or criticality, with the highest priority or criticality supported on the frequency or a greater number of related multicast sessions of the UE (100) supported. Criticality may refer to emergency or critical communications such as public safety services or mission critical push-to-talk (MCPTT) services.

[0118] c) Frequencies of multicast sessions that are not supported and / or are received in RRC_INACTIVE state are prioritized in the order of their cellReselectionPriority.

[0119] d) Frequencies indicated as part of the deprioritisationReqforMulticast are considered as lowest priority or restricted for cell reselection.

[0120] e) Consider the frequency and / or frequency priority for multicast session reception under RRC_INACTIVE, which is provided to the UE (100) in broadcast signaling (such as User Service Description (USD) message and / or System Information Block (SIB) message).

[0121] In an embodiment, the UE (100) may not consider the cell and / or other cells on the same frequency as candidates for reselection because the cell or best cell ranked highest according to the absolute priority reselection rule (which may be a same-frequency cell or a different-frequency cell) is not a candidate for reselection due to non-support of multicast and / or non-support of related multicast sessions, and / or is signaled as not being in multicast coverage and / or involving a reduction in priority ReqFormulticast. The UE (100) may not consider the cell and / or other cells on the same frequency as candidates for reselection within a predefined maximum time period. In the example herein, the UE (100) may not consider the cell and / or other cells on the same frequency as candidates for reselection for a maximum of 300 seconds.

[0122] In an embodiment, cell reselection of a UE (100) that is interested in and / or receiving multicast in RRC_INACTIVE state is triggered when at least one of the performance trigger conditions is met (e.g., the channel condition measured by the UE (100) meets a determined threshold of the multicast reception performance), broadcast signaling for cell reselection change (e.g., a cell reselection configuration parameter in the SIB or MCCH is changed), a multicast session / MRB information change (e.g., a multicast session is released, the UE's interest in the multicast session changes, the session is deactivated or activated), and a priority reduction / congestion status information change.

[0123] In an embodiment, cell reselection for a UE (100) receiving one or more multicast sessions in RRC_INACTIVE state is blocked or deprioritized to a cell or frequency that does not support the one or more multicast sessions.

[0124] In another embodiment, cell reselection for a UE (100) receiving one or more multicast sessions in RRC_INACTIVE state is blocked or deprioritized to a cell or frequency that does not support the one or more multicast sessions configured for the UE (100) and being received by the UE (100).

[0125] In an embodiment, when the UE (100) moves across cells, the gNB delivers multicast session information (e.g., TMGI, session configuration) to other gNBs (e.g., gNBs). The gNB may deliver the multicast session information of the UE (100) to one or more gNBs via an Xn interface. The gNBs may belong to the same RNA.

[0126] In an embodiment, the UE (100) may be provided by the network device (200) in at least one of broadcast signaling (e.g., system information block (SIB) or MCCH) and / or dedicated signaling (e.g., RRC reconfiguration message, RRC release message, RRCRelease message with suspendConfig), cellReselectionPriority and / or multicast-cellReselectionPriority that determine the priority of the frequency for cell reselection. In an embodiment, multicast-cellReselectionPriority may only apply to UEs (100) that are configured and / or interested in receiving multicast. In some cases, this may be limited to UEs (100) that are configured / capable and / or interested in and / or are receiving multicast in the RRC_INACTIVE state.

[0127] In an embodiment, if any field with cellReselectionPriority or multicast-CellReselectionPriority is provided in dedicated signaling, the UE (100) shall ignore any field with cellReselectionPriority and mutlicast-CellReselectionPriority provided in system information. The validity of the priority provided by dedicated signaling may reach a configured time limit (e.g., timer T320 expires).

[0128] In an embodiment, the network device (200) provides a "reduced priority configuration for multicast reception" to the UE (100) to guide the cell reselection process in the RRC_INACTIVE state. The reduced priority configuration for multicast reception can be provided by at least one of an RRC release message with suspendconfig (when the UE (100) transitions from RRC_CONNECTED to RRC_INACTIVE) or an RRCReject message (when the UE (100) attempts to access the network). The reduced priority configuration for multicast reception may include one or more configuration sets of at least one of frequency, radio access technology (RAT, such as NR), cell identity, multicast session identity (e.g., TMGI), reduction priority timer Txyz configuration, reduction priority reason (e.g., congestion, overload), and applicable RRC state. The reduced priority configuration for multicast reception may only apply to UEs (100) that are interested in receiving a multicast session and / or are receiving a multicast session. In an embodiment, the reduced priority configuration for multicast reception may only apply to UEs that are configured / capable and / or interested and / or are receiving the multicast session in RRC_INACTIVE state.

[0129] In an embodiment, when the UE (100) receives a reduced priority configuration for multicast reception with one or more timer configurations, the UE (100) stores the reduced priority configuration for multicast reception and maintains one or more instances of the timer Txyz. The UE (100) may receive multiple reduced priorities for multicast reception at different points in time; for example, during multiple RRCRejects or RRCReleases with SuspendConfig, when a previous reduced priority configuration for multicast reception is already stored in the UE (100). Using different instances of the timer Txyz, multiple different reduced priority configurations for multicast reception associated with different frequencies can be efficiently and correctly handled. An example of the specification text is presented as follows:

[0130] Example 1:

[0131] 1> If deprioritisationReqforMulticast is included in RRCRelease including SuspendConfig and the UE (100) supports RRC connection release with deprioritisation for multicast:

[0132] 2> Start timer Txyz, where the timer value is set to the signaled deprioritisationTimer;

[0133] 2>Store deprioritisationReqforMulticast until Txyz expires;

[0134] Example 2:

[0135] 1> If deprioritisationReqforMulticast is included in RRCRelease including SuspendConfig and the UE (100) supports RRC connection release with reduced priority for multicast:

[0136] 2> Start an instance of timer Txyz, where the timer value is set to the signaled deprioritisationTimer;

[0137] 2>Store deprioritisationReqforMulticast until the relevant instance of timer Txyz expires;

[0138] In an embodiment, the UE (100) stores one or more deprioritisationReqforMulticast until the relevant instance of the Txyz timer expires, regardless of the RRC state change and / or cell reselection absolute priority allocation made by dedicated or common signaling.

[0139] In an embodiment, the UE (100) stores one or more deprioritisationReqforMulticast until the common and individual Txyx timers expire, regardless of RRC state changes and / or cell reselection absolute priority assignments made via dedicated or common signaling. When the UE (100) receives a new deprioritisationReqforMulticast from the network, the Txyz timer is started and / or restarted.

[0140] In an embodiment, if the UE (100) receives a deprioritisationReqforMulticast in an RRC release with suspendConfig and / or broadcast signaling, the UE (100) may treat the current frequency and the frequency stored due to the deprioritisationReqforMulticast previously received in the RRC release with suspendConfig and / or broadcast signaling as the lowest priority frequency (i.e., lower than any network configuration value) while the relevant Txyz is running. When performing PLMN selection or SNPN selection according to the request of NAS, the UE (100) may delete the stored deprioritisationReqforMulticast request.

[0141] In an embodiment, a deprioritisationReqforMulticast is provided to the UE (100) so as to transition the UE (100) and / or maintain the UE (100) in the RRC_INACTIVE state to receive or continue to receive multicast services when there is overload or congestion on the current cell or frequency. In addition, when the overload or congestion on the current cell or frequency is not applicable, the deprioritisationReqforMulticast is released, and the UE (100) can transition to RRC_CONNECTED to receive or continue to receive multicast services.

[0142] In an embodiment, an example structure of a reduced priority configuration for multicast reception is presented as follows:

[0143]

[0144]

[0145] In an embodiment, information is provided by broadcast signaling to signal a reduced priority for multicast reception (and / or a congestion indication, typically used to inhibit the UE (100) from attempting to transition to the RRC_CONNECTED state) to a UE (100) already in the RRC_INACTIVE state (and / or the RRC_IDLE state). The broadcast signaling may include at least one of SIB, MCCH, and group paging or notification.

[0146] In an embodiment, the network device (200) may release (or remove) the reduced priority for multicast reception for the UE (100) (and / or release / remove the congestion indication, typically to allow the UE (100) to attempt to access the multicast in the RRC_CONNECTED state). The release of the reduced priority for multicast reception (and / or the release of the congestion indication) may be provided by dedicated RRC signaling and / or broadcast signaling, which may include at least one of SIB, MCCH, and group paging or notification.

[0147] In an embodiment, the UE (100) removes one or more stored deprioritisationReqforMulticast when the UE (100) receives a release of the related deprioritisationReqforMulticast and the UE (100) stops and resets the related Txyz timer.

[0148] In an embodiment, upon receiving an RRCRelease with SuspendConfig to transition to the RRC_INACTIVE state, the UE (100) may attempt to camp on a suitable cell based on redirectedCarrierInfo and / or redirectedCarrierInfoMulticast (if included in the message), which directs the UE (100) to a cell / frequency that supports the multicast session to be received under RRC_INACTIVE. If the RRCRelease message does not include redirectedCarrierInfo and / or redirectedCarrierInfoMulticast, the UE (100) should attempt to select a suitable cell on the NR carrier that can support multicast reception. If no suitable cell is found based on the above, the UE (100) will perform cell selection using the stored information in order to find a suitable cell to camp on that can support multicast reception.

[0149] Figure 2 Various hardware components of a UE (100) according to an embodiment disclosed herein are shown. In an embodiment, the UE (100) includes a processor (110), a communicator (120), a memory (130), and an MBS multicast service controller (140). The processor (110) is coupled to the communicator (120), the memory (130), and the MBS multicast service controller (140).

[0150] When the UE (100) is in a mobility scenario, the MBS multicast service controller (140) determines a multicast reception to be received in an RRC inactive state. In addition, the MBS multicast service controller (140) receives a message supporting a mobility scenario of the UE (100) in an RRC inactive state from a network device (200). The message may be, for example, but not limited to, multicast service coverage information supporting the mobility of the UE (100), a multicast inclusion list for cell reselection of a multicast service, a multicast exclusion list for cell reselection of a multicast service, a list of neighboring cell information, applicability information of a multicast configuration of a serving cell for at least one neighboring cell, a neighboring cell multicast configuration, a cell status indication for multicast reception, a cell reservation indication for multicast reception, a cell reselection priority, and a priority of a frequency for cell reselection.

[0151] In an embodiment, the multicast service coverage information includes a neighboring cell list of the serving cell and a frequency supporting the multicast service. The multicast service coverage information is provided by at least one of an RRC reconfiguration message carrying an MRB configuration for the multicast service, an RRC release message with suspendconfig carrying an MRB configuration for multicast service reception, SIB, and MCCH signaling.

[0152] The cell status indication and the cell reservation indication include a multicastCellBarred field, a multicastCellBarred-inactive field, a multicastSupport field, and a multicastSupport-inactive field. The multicastCellBarred field and / or the multicastCellBarred-inactive field indicate whether the cell is prohibited from being used for multicast reception in the RRC inactive state. The multicastSupport field and the multicastSupport-inactive field indicate whether multicast reception is supported in the RRC inactive state. The cell status indication for multicast reception and the cell reservation indication for multicast reception are received in at least one of a MIB message, a SIB1 message, an MBS SIB message, and an MCCH message.

[0153] Based on the received message, the MBS multicast service controller (140) processes the multicast reception of the UE (100).

[0154] In the example, the MBS multicast service controller (140) reselects a cell in the RNA or multicast coverage area and continues multicast reception in the cell based on receiving an indication from the network device (200) about all neighboring cells including exactly the same multicast MBS radio bearer (MRB) configuration information in the RNA through a message including neighbor cell multicast configuration.

[0155] In another example, the MBS multicast service controller (140) prioritizes the cell and reselects the cell in the RNA or the multicast coverage area. In addition, the MBS multicast service controller (140) continues multicast reception in the cell based on receiving an indication of all neighboring cells in the RNA or the multicast coverage area including multicast MRB information that is identical to the multicast MRB information of the serving cell from the network device (200) through a message including the neighboring cell multicast configuration.

[0156] In another example, the MBS multicast service controller (140) prioritizes cells and reselects a cell providing a multicast service of interest to the UE (100) based on receiving an indication from a network device (200) via a message including a neighbor cell multicast configuration regarding all neighbor cells in an RNA or multicast coverage area that include multicast MRB information that is different from the multicast MRB information of the serving cell.

[0157] In another example, an MBS multicast service controller (140) indicates interest to a network device (200) upon determining that a UE (100) performs cell reselection on a cell that does not provide an activated multicast service that the UE (100) is receiving. The indication is provided to at least one of an MBS interest indication message, a UE assistance information message, a short message, and a preconfigured random access preamble. The interest is indicated to the network device (200) after the UE (100) transitions from an RRC inactive state to an RRC connected state.

[0158] In another example, the MBS multicast service controller (140) performs at least one of: continuing to listen to group paging or notification for activation or deactivation of a multicast session, and receiving the multicast session on a reselected cell. In addition, when the UE (100) performs reselection to a neighboring cell, the MBS multicast service controller (140) uses the neighboring cell information to determine support for the multicast session on the reselected cell and configuration of the multicast session.

[0159] In another example, the MBS multicast service controller (140) stops or reduces the priority of cell reselection to a cell or frequency that does not support the multicast session. In another example, when the cell reselection to a cell or frequency does not support the multicast session of interest to the UE (100), the MBS multicast service controller (140) transitions to the RRC connected state. In addition, the MBS multicast service controller (140) stops listening to multicast paging or notifications.

[0160] In an embodiment, when the UE (100) is interested in receiving multicast services in an RRC inactive state, the MBS multicast service controller (140) does not consider cells in the multicast exclusion list as candidate cells for cell reselection.

[0161] In another embodiment, when the UE (100) is interested in receiving multicast services in an RRC inactive state, the MBS multicast service controller (140) considers cells in the multicast inclusion list as candidate cells for cell reselection.

[0162] In another embodiment, when the UE (100) is configured to receive multicast communications in an RRC inactive state, the MBS multicast service controller (140) considers a frequency providing or supporting multicast communications as the highest priority when performing cell reselection.

[0163] In another embodiment, the MBS multicast service controller (140) prioritizes at least one of neighboring cells and frequencies for cell reselection based on at least one of the strongest cell belonging to the highest reselection priority frequency, the ranking of the cell, the signal strength of the cell, support for prioritized multicast sessions on the cell, and the status of multicast session support on the cell for the UE (100), and support for a maximum number of related multicast sessions on the cell for the UE (100).

[0164] In another embodiment, when the selected cell or frequency does not support a multicast session, the MBS multicast service controller (140) re-derives the reselection priority of the frequency by considering the multicast sessions supported by the cell.

[0165] In another embodiment, the MBS multicast service controller (140) determines the priority of frequencies for cell reselection based on at least one of a broadcast signaling message, a dedicated signaling message, a cell reselection priority message, and a multicast cell reselection priority message received from the network device (200).

[0166] In another embodiment, the MBS multicast service controller (140) derives a reselection priority for cell reselection while the UE (100) is configured to receive at least one multicast session in an RRC inactive state based on at least one of the following: a frequency supporting at least one multicast session has a higher reselection priority than another frequency not supporting the multicast session, the frequency being determined based on the cell reselection priority and a request for a reduction in priority for multicast, the frequency supporting at least one multicast session prioritized based on critical services, wherein the critical services include at least one of the following: public safety services, mission critical push-to-talk (MCPTT) services.

[0167] In an embodiment, cell reselection of a UE (100) interested in receiving multicast in an RRC inactive state is triggered when at least one of a performance trigger condition is met (e.g., a channel condition measured by the UE meets a determined threshold of multicast reception performance), a broadcast signaling change for cell reselection (e.g., a cell reselection configuration parameter change in the SIB or MCCH), a multicast session / MRB information change (e.g., a multicast session is released, the UE's interest in the multicast session changes, the session is deactivated or activated), and a priority reduction / congestion status information change.

[0168] In an embodiment, the MBS multicast service controller (140) receives an RRC release with a suspended configuration. In addition, the MBS multicast service controller (140) receives a priority reduction request for the multicast configuration. In addition, the MBS multicast service controller (140) stores the priority reduction request for the multicast configuration. In addition, the MBS multicast service controller (140) starts a timer and maintains the priority reduction request for the multicast configuration until the timer expires or a release of the priority reduction request for the multicast configuration is received. In addition, the MBS multicast service controller (140) performs cell reselection in RRC inactivity. In addition, the MBS multicast service controller (140) considers the current frequency or the frequency indicated in the stored priority reduction request for the multicast configuration as the lowest priority.

[0169] The MBS multicast service controller (140) is 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.

[0170] In addition, the processor (110) is configured to execute instructions stored in the memory (130) and perform various processes. The communicator (120) is configured to communicate internally between internal hardware components and to communicate internally with external devices via one or more networks. The memory (130) also stores instructions to be executed by the processor (110). The memory (130) may include a non-volatile storage element. Examples of such non-volatile storage elements may include a magnetic hard disk, an optical disk, a floppy disk, a flash memory, or a form of an electrically programmable memory (EPROM) or an electrically erasable programmable (EEPROM) memory. In addition, in some examples, the memory (130) may be considered to be a non-transitory storage medium. The term "non-transitory" may indicate that the storage medium is not embodied in a carrier or propagating signal. However, the term "non-transitory" should not be interpreted as the memory (130) being non-removable. In some instances, a non-transitory storage medium may store data that may change over time (e.g., in a random access memory (RAM) or a cache memory).

[0171] although Figure 2 Various hardware components of the UE (100) are shown, but it should be understood that other embodiments are not limited thereto. In other embodiments, the UE (100) may include fewer or more components. In addition, the labels or names of the components are only for illustrative purposes and do not limit the scope of the present disclosure. One or more components may be combined together to perform the same or substantially similar functions in the UE (100).

[0172] Figure 3Various hardware components of a network device (200) according to an embodiment disclosed herein are shown. In an embodiment, the network device (200) includes a processor (210), a communicator (220), a memory (230), and an MBS multicast service controller (240). The processor (210) is coupled to the communicator (220), the memory (230), and the MBS multicast service controller (240).

[0173] The MBS multicast service controller (240) sends a message to the UE (100) supporting the mobility scenario of the UE (100) in the RRC inactive state. The message may be, for example but not limited to, multicast service coverage information supporting the mobility of the UE (100), a multicast inclusion list for cell reselection of the multicast service, a multicast exclusion list for cell reselection of the multicast service, a list of neighboring cell information, applicability information of a multicast configuration of a serving cell for at least one neighboring cell, a neighboring cell multicast configuration, a cell state indication for multicast reception, a cell reservation indication for multicast reception, a cell reselection priority, and a priority of a frequency for cell reselection. In addition, the MBS multicast service controller (240) processes the multicast reception of the UE (100) based on the message.

[0174] The MBS multicast service controller (240) is 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.

[0175] In addition, the processor (210) is configured to execute instructions stored in the memory (230) and perform various processes. The communicator (220) is configured to communicate internally between internal hardware components and to communicate internally with external devices via one or more networks. The memory (230) also stores instructions to be executed by the processor (210). The memory (230) may include a non-volatile storage element. Examples of such non-volatile storage elements may include a magnetic hard disk, an optical disk, a floppy disk, a flash memory, or a form of an electrically programmable memory (EPROM) or an electrically erasable programmable (EEPROM) memory. In addition, in some examples, the memory (230) may be considered to be a non-transitory storage medium. The term "non-transitory" may indicate that the storage medium is not embodied in a carrier or propagation signal. However, the term "non-transitory" should not be interpreted as the memory (230) being non-removable. In some instances, a non-transitory storage medium may store data that may change over time (e.g., in a random access memory (RAM) or a cache memory).

[0176] although Figure 3Various hardware components of the network device (200) are shown, but it should be understood that other embodiments are not limited thereto. In other embodiments, the network device (200) may include fewer or more components. In addition, the labels or names of the components are only for illustrative purposes and do not limit the scope of the present disclosure. One or more components can be combined together to perform the same or substantially similar functions in the network device (200).

[0177] Figure 4 is a flow chart (400) illustrating a method implemented by a UE (100) for handling multicast reception in an RRC inactive state in a wireless network (1000) according to an embodiment disclosed herein. Operations (402-406) are processed by an MBS multicast service controller (140).

[0178] In step 402, the method includes determining a multicast reception to be received in an RRC inactive state when the UE (100) is in a mobility scenario. In step 404, the method includes receiving a message from a network device (200) that supports a mobility scenario for the UE (100) in an RRC inactive state. The message may be, for example, but not limited to, multicast service coverage information supporting the mobility of the UE (100), a multicast inclusion list for cell reselection of the multicast service, a multicast exclusion list for cell reselection of the multicast service, a list of neighboring cell information, applicability information of a multicast configuration of a serving cell for at least one neighboring cell, a neighboring cell multicast configuration, a cell state indication for multicast reception, a cell reservation indication for multicast reception, a cell reselection priority, and a priority of a frequency for cell reselection. In step 406, the method includes processing the multicast reception of the UE (100) in the mobility scenario based on the received message.

[0179] In an embodiment, processing the multicast reception of the UE (100) based on the received comprises stopping cell reselection to a cell or frequency that does not support the multicast session.

[0180] In another embodiment, processing multicast reception of the UE (100) based on the received message includes performing at least one of: continuing to listen to the group paging or notification of activation of the multicast session and receiving the multicast session on the reselected cell, and when the UE (100) performs reselection to a neighboring cell, using the neighboring cell information to determine support of the multicast session and configuration of the multicast session on the reselected cell.

[0181] In another embodiment, processing multicast reception by the UE (100) based on the received message includes indicating interest to the network device (200) upon determining that the UE (100) is performing cell reselection to a cell.

[0182] In another embodiment, processing multicast reception of the UE (100) based on the received message includes: reselecting a cell in the RNA, and continuing multicast reception in the cell based on receiving an indication from the network device (200) about all neighboring cells in the RNA or multicast coverage area that include multicast MRB information that is exactly the same as the multicast MRB information of the serving cell through a message including at least one neighboring cell multicast configuration.

[0183] In another embodiment, processing multicast reception of the UE (100) based on the received message includes: prioritizing the cell, and based on receiving an indication from the network device (200) about a neighboring cell in the RNA or multicast coverage area including multicast MRB information that is exactly the same as the multicast MRB information of the serving cell through a message including at least one neighboring cell multicast configuration, reselecting the cell in the RNA and continuing the multicast reception in the cell.

[0184] In another embodiment, processing multicast reception of a UE (100) based on received messages includes: prioritizing cells and reselecting cells providing multicast services of interest to the UE (100) based on receiving an indication from a network device (200) about all neighboring cells whose RNAs include multicast MRB information that is different from the multicast MRB information of a serving cell via a message including at least one neighboring cell multicast configuration.

[0185] Figure 5 is a flow chart (500) depicting a method implemented by a UE (100) for enabling a UE (100) to perform cell reselection in an RRC inactive state according to embodiments disclosed herein. Operations (502-514) are processed by an MBS multicast service controller (140).

[0186] At step 502, the method includes receiving an RRC release with a suspended configuration. At step 504, the method includes receiving a deprioritization request for a multicast configuration. At step 506, the method includes storing the deprioritization request for the multicast configuration. At step 508, the method includes starting a timer. At step 510, the method includes maintaining the deprioritization request for the multicast configuration until the timer expires or a release of the deprioritization request for the multicast configuration is received. At step 512, the method includes performing a cell reselection under RRC inactivity. At step 514, the method includes treating the current frequency or the frequency indicated in the stored deprioritization request for the multicast configuration as the lowest priority.

[0187] In an example, when the UE (100) receives an RRC release with a suspension configuration and a deprioritizationReqForMulticast configuration, the UE (100) stores the deprioritizationReqForMulticast configuration and starts a timer Txyz (an instance). The UE (100) maintains the deprioritizationReqForMulticast configuration until the timer Txyz (the associated instance) expires and / or a release of the associated deprioritizationReqForMulticast configuration has been received. The UE (100) performs cell reselection under RRC_INACTIVE and considers one or more current frequencies indicated in the stored deprioritizationReqforMulticast configuration as the lowest priority.

[0188] Figure 6 is a flow chart (600) illustrating a method implemented by a network device (200) for handling multicast reception in an RRC inactive state in a wireless network (1000) according to an embodiment disclosed herein. Operations (602-604) are processed by an MBS multicast service controller (240).

[0189] At step 602, the method includes sending a message to the UE (100) supporting a mobility scenario of the UE (100) in an RRC inactive state. At step 604, the method includes processing multicast reception of the UE (100) in the mobility scenario based on the message.

[0190] Figure 7 is an example flow chart (700) illustrating a method for managing the mobility of a UE receiving NR MBS multicast service in an RRC inactive state according to an embodiment disclosed herein.

[0191] In step 702, the network device (200) provides the neighboring cell multicast configuration of the UE (100) to other cells in the same RNA. In step 704, all neighboring cells in the RNA have multicast MRB information that is exactly the same as the multicast MRB information of the serving cell, and the network device (200) indicates the multicast MRB information to the UE (100). In step 706, the UE (100) reselects any cell in the RNA and continues multicast reception.

[0192] At step 708, the neighboring cell has multicast MRB information that is identical to the multicast MRB information of the serving cell, and the gNB may indicate the neighboring cell. At step 710, the UE (100) may prioritize the cells. Based on this, the UE (100) reselects the cell and continues multicast reception.

[0193] At step 712, the neighboring cells have different multicast MRB information, and the gNB may provide the neighboring cell MRB configuration. At step 714, the UE (100) may prioritize the cell that is providing the multicast service of interest to the UE (100).

[0194] At step 716, the neighboring cell does not provide the multicast service that the UE is interested in. At step 718, when the UE (100) reselects a cell, the UE (100) enters an RRC connection. It may be based on group paging or on its own. At step 720, the UE (100) may indicate to the gNB that the UE (100) is interested in the multicast service.

[0195] This method can be used to ensure the maintenance and continuity of multicast services and the mobility of UEs in the RRC_INACTIVE state.

[0196] Figure 8 An electronic device according to an embodiment of the present disclosure is shown.

[0197] refer to Figure 8 , the electronic device 800 may include a processor 810, a transceiver 820, and a memory 830. However, all the components shown are not required. The electronic device 800 may be composed of Figure 8 The components shown in the figure may be implemented with more or fewer components. In addition, according to another embodiment, the processor 810, the transceiver 820, and the memory 830 may be implemented as a single chip.

[0198] The electronic device 800 may correspond to the above-mentioned UE.

[0199] The aforementioned components will now be described in detail.

[0200] The processor 810 may include one or more processors or other processing devices that control the proposed functions, processes and / or methods. The operations of the electronic device 800 may be implemented by the processor 810.

[0201] The transceiver 820 may include an RF transmitter for up-converting and amplifying a transmitted signal, and an RF receiver for down-converting the frequency of a received signal. However, according to another embodiment, the transceiver 820 may be implemented by more or less components than those illustrated in the components.

[0202] The transceiver 820 may be connected to the processor 810 and transmit and / or receive signals. The signal may include control information and data. In addition, the transceiver 820 may receive a signal through a wireless channel and output the signal to the processor 810. The transceiver 820 may transmit a signal output from the processor 810 through a wireless channel.

[0203] The memory 830 may store control information or data included in the signal obtained by the electronic device 800. The memory 830 may be connected to the processor 810 and store at least one instruction or protocol or parameter for the proposed function, process and / or method. The memory 830 may include a read-only memory (ROM) and / or a random access memory (RAM) and / or a hard disk and / or a CD-ROM and / or a DVD and / or other storage devices.

[0204] Fig. 9 A base station according to various embodiments of the present disclosure is shown.

[0205] refer to Fig. 9 , the base station 900 may include a processor 910, a transceiver 920, and a memory 930. However, all the components shown are not required. The base station 900 may include a processor 910, a transceiver 920, and a memory 930. Fig. 9 The components shown in the figure may be implemented with more or less components. In addition, according to another embodiment, the processor 910, the transceiver 920, and the memory 930 may be implemented as a single chip.

[0206] The base station 900 may correspond to a gNB or the above-mentioned network device.

[0207] The aforementioned components will now be described in detail.

[0208] The processor 910 may include one or more processors or other processing devices that control the proposed functions, processes and / or methods. The operations of the base station 900 may be implemented by the processor 910.

[0209] The transceiver 920 may include an RF transmitter for up-converting and amplifying a transmitted signal, and an RF receiver for down-converting the frequency of a received signal. However, according to another embodiment, the transceiver 920 may be implemented by more or less components than those shown in the components.

[0210] The transceiver 920 may be connected to the processor 910 and transmit and / or receive signals. The signals may include control information and data. In addition, the transceiver 920 may receive signals through a wireless channel and output the signals to the processor 910. The transceiver 920 may transmit signals output from the processor 910 through a wireless channel.

[0211] The memory 930 may store control information or data included in a signal obtained by the base station 900. The memory 930 may be connected to the processor 910 and store at least one instruction or protocol or parameter for the proposed function, process and / or method. The memory 930 may include a read-only memory (ROM) and / or a random access memory (RAM) and / or a hard disk and / or a CD-ROM and / or a DVD and / or other storage devices.

[0212] According to an embodiment, a method for handling multicast reception in a wireless network (1000) may be provided.

[0213] According to an embodiment, the method may include determining, by a user equipment (UE) (100), a multicast reception to be received in a radio resource control (RRC) inactive state when the UE (100) is in a mobility scenario.

[0214] According to an embodiment, the method may include receiving, by the UE (100) from the network device (200), at least one message supporting a mobility scenario of the UE (100) in an RRC inactive state.

[0215] According to an embodiment, at least one message may include at least one of the following: multicast service coverage information supporting the mobility of the UE (100), a multicast inclusion list for cell reselection of the multicast service, a multicast exclusion list for cell reselection of the multicast service, a list of neighboring cell information, applicability information of the multicast configuration of a service cell for at least one neighboring cell, a neighboring cell multicast configuration, a cell status indication for multicast reception, a cell reservation indication for multicast reception, a cell reselection priority, and a priority of a frequency for cell reselection.

[0216] According to an embodiment, the method may include handling, by the UE (100), multicast reception of the UE (100) in a mobility scenario based on the received at least one message.

[0217] According to an embodiment, the at least one multicast service coverage information may include at least one of a neighbor cell list of the serving cell and a frequency supporting the multicast service.

[0218] According to an embodiment, at least one multicast service coverage information may be provided via at least one of an RRC reconfiguration message carrying an MBS radio bearer (MRB) configuration for multicast service, an RRC release and suspendconfig message carrying an MRB configuration for multicast service reception, a system information block (SIB), and an MBS control channel (MCCH) signaling.

[0219] According to an embodiment, when the UE (100) is interested in receiving multicast services in an RRC inactive state, the UE (100) may not consider cells in the multicast exclusion list as candidate cells for cell reselection, wherein, when the UE (100) is interested in receiving multicast services in an RRC inactive state, the UE (100) considers at least one cell in the multicast inclusion list as a candidate cell for cell reselection.

[0220] According to an embodiment, at least one of the cell status indication or the cell reservation indication may include at least one of a multicastCellBarred field, a multicastCellBarred-inactive field, a multicastSupport field, and a multicastSupport-inactive field.

[0221] According to an embodiment, at least one of the multicastCellBarred field or the multicastCellBarred-inactive field may indicate whether the cell is prohibited for multicast reception in an RRC inactive state.

[0222] According to an embodiment, at least one of the multicastSupport field or the multicastSupport-inactive field may indicate whether multicast reception is supported in the RRC inactive state.

[0223] According to an embodiment, the cell state indication for multicast reception and the cell reservation indication for multicast reception may be received in at least one of a MIB message, a SIB1 message, an MBS SIB message, and a MCCH message.

[0224] According to an embodiment, processing, by the UE (100), multicast reception of the UE (100) in a mobility scenario based on at least one received message may include performing at least one of the following: based on receiving an indication of all neighboring cells in a notification area (RNA) or a multicast coverage area based on a radio access network including multicast MBS radio bearer (MRB) configuration information that is exactly the same as that of a serving cell through at least one message including at least one neighboring cell multicast configuration from a network device (200), reselecting a cell in the RNA or a multicast coverage area, and continuing multicast reception in the cell; based on receiving an indication of all neighboring cells in a notification area (RNA) or a multicast coverage area based on a radio access network including multicast MBS radio bearer (MRB) configuration information that is exactly the same as that of a serving cell through at least one message including at least one neighboring cell multicast configuration from a network device (200), reselecting a cell in the RNA or a multicast coverage area, and continuing multicast reception in the cell; At least one message of a neighboring cell multicast configuration receives from a network device (200) an indication of neighboring cells in an RNA or multicast coverage area that include multicast MRB information that is exactly the same as the multicast MRB information of a serving cell, prioritizes the cells, and reselects the cells in the RNA or multicast coverage area and continues multicast reception in the cells; based on receiving from the network device (200) an indication of all neighboring cells in an RNA or multicast coverage area that include multicast MRB information that is different from the multicast MRB information of the serving cell through at least one message including at least one neighboring cell multicast configuration, prioritizes the cells, and reselects the cells that provide the multicast service of interest to the UE (100).

[0225] According to an embodiment, when the UE (100) is configured to receive multicast communication in an RRC inactive state, the UE (100) may consider a frequency providing or supporting multicast communication as the highest priority when performing cell reselection.

[0226] According to an embodiment, the UE (100) can prioritize at least one of the neighboring cells and frequencies for cell reselection based on at least one of the following: the strongest cell belonging to the highest reselection priority frequency, the ranking of the cell, the signal strength of the cell, the support for prioritized multicast sessions on the cell, and the status of multicast session support on the cell for the UE (100), and the support for the maximum number of related multicast sessions on the cell for the UE (100).

[0227] According to an embodiment, when the selected cell or frequency does not support a multicast session, the UE (100) may re-derive the reselection priority of the frequency by considering the multicast sessions supported by the cell.

[0228] According to an embodiment, the UE (100) may determine the priority of frequencies for cell reselection based on at least one of a broadcast signaling message, a dedicated signaling message, a cell reselection priority message, and a multicast cell reselection priority message received from the network device (200).

[0229] According to an embodiment, a UE (100) may derive a reselection priority for cell reselection while the UE (100) is configured to receive at least one multicast session in an RRC inactive state based on at least one of the following: a frequency supporting at least one multicast session has a higher reselection priority than another frequency not supporting the multicast session, the frequency being determined based on the cell reselection priority and a request for a reduction in priority for multicast, the frequency supporting at least one multicast session prioritized based on a critical service.

[0230] According to an embodiment, the critical service may include at least one of a public safety service, a mission critical push-to-talk (MCPTT) service.

[0231] According to an embodiment, processing by the UE (100) of multicast reception in a mobility scenario based on at least one received message may include: indicating interest to a network device (200) upon determining that the UE (100) performs cell reselection to a cell, wherein the cell does not provide at least one activated multicast service being received by the UE (100), wherein the indication is provided by at least one of an MBS interest indication message, a UE assistance information message, a short message, and a preconfigured random access preamble, wherein the interest is indicated to the network device (200) after the UE (100) transitions from an RRC inactive state to an RRC connected state.

[0232] According to an embodiment, processing of multicast reception of a UE (100) in a mobility scenario by the UE (100) based on at least one received message may include: performing at least one of the following: continuing to listen to group paging or notification to activate or deactivate at least one multicast session, and receiving at least one multicast session on a reselected cell, and when the UE (100) performs reselection to a neighboring cell, using neighboring cell information to determine support for the multicast session and configuration of the multicast session on the reselected cell.

[0233] According to an embodiment, processing of multicast reception of a UE (100) in a mobility scenario by the UE (100) based on at least one received message may include at least one of: stopping or lowering the priority of cell reselection to a cell or frequency that does not support at least one multicast session of interest to the UE (100); and transitioning to an RRC connected state when cell reselection to a cell or frequency does not support at least one multicast session of interest to the UE (100).

[0234] According to an embodiment, cell reselection of a UE (100) interested in receiving multicast in an RRC inactive state may be triggered when at least one of a performance trigger condition, a change in broadcast signaling for cell reselection, a change in multicast session, a change in MRB information, a change in reduced priority, and a change in congestion status information is met.

[0235] According to an embodiment, a method for handling multicast reception in a wireless network (1000) may be provided.

[0236] According to an embodiment, the method may include receiving, by the UE (100), a radio resource control (RRC) release with a suspension configuration.

[0237] According to an embodiment, the method may include receiving, by the UE (100), a lower priority request for a multicast configuration.

[0238] According to an embodiment, the method may comprise storing, by the UE (100), a deprioritization request for the multicast configuration.

[0239] According to an embodiment, the method may include starting a timer by the UE (100).

[0240] According to an embodiment, the method may include maintaining, by the UE (100), the request to lower the priority of the multicast configuration until a timer expires or a release of the request to lower the priority of the multicast configuration is received.

[0241] According to an embodiment, the method may include performing cell reselection by the UE (100) in RRC inactivation.

[0242] According to an embodiment, the method may include considering, by the UE (100), the current frequency or a frequency indicated in a stored deprioritization request for the multicast configuration as the lowest priority.

[0243] According to an embodiment, a method for handling multicast reception in a wireless network (1000) may be provided.

[0244] According to an embodiment, the method may include sending, by a network device (200) to a UE (100), at least one message supporting a mobility scenario of a user equipment (UE) (100) in an RRC inactive state.

[0245] According to an embodiment, at least one message may include at least one of the following: multicast service coverage information supporting the mobility of the UE (100), a multicast inclusion list for cell reselection of the multicast service, a multicast exclusion list for cell reselection of the multicast service, a list of neighboring cell information, applicability information of the multicast configuration of a service cell for at least one neighboring cell, a neighboring cell multicast configuration, a cell status indication for multicast reception, a cell reservation indication for multicast reception, a cell reselection priority, and a priority of a frequency for cell reselection.

[0246] According to an embodiment, the method may include handling, by a network device (200), multicast reception of a UE (100) in a mobility scenario based on at least one message.

[0247] According to an embodiment, the at least one multicast service coverage information may include at least one of a neighbor cell list of the serving cell and a frequency supporting the multicast service.

[0248] According to an embodiment, at least one multicast service coverage information may be provided via at least one of an RRC reconfiguration message carrying an MBS radio bearer (MRB) configuration for multicast service, an RRC release and suspendconfig message carrying an MRB configuration for multicast service reception, a system information block (SIB), and an MBS control channel (MCCH) signaling.

[0249] According to an embodiment, at least one of the cell status indication or the cell reservation indication may include at least one of a multicastCellBarred field, a multicastCellBarred-inactive field, a multicastSupport field and a multicastSupport-inactive field, wherein at least one of the multicastCellBarred field and the multicastCellBarred-inactive field indicates whether the cell is prohibited from being used for multicast reception in an RRC inactive state.

[0250] According to an embodiment, at least one of the multicastSupport field or the multicastSupport-inactive field may indicate whether multicast reception is supported in the RRC inactive state.

[0251] According to an embodiment, the cell state indication for multicast reception and the cell reservation indication for multicast reception may be received in at least one of a MIB message, a SIB1 message, an MBS SIB message, and a MCCH message.

[0252] According to an embodiment, a user equipment (UE) (100) may be provided. According to an embodiment, the UE (100) may include a processor (110); a memory (130); and an MBS multicast service controller (140) coupled to the processor (110) and the memory (130).

[0253] According to an embodiment, the MBS multicast service controller (140) may be configured to determine multicast reception to be received in a radio resource control (RRC) inactive state when the UE (100) is in a mobility scenario.

[0254] According to an embodiment, the MBS multicast service controller (140) may be configured to receive at least one message supporting a mobility scenario of a UE (100) in an RRC inactive state from a network device (200).

[0255] According to an embodiment, at least one message may include at least one of the following: multicast service coverage information supporting the mobility of the UE (100), a multicast inclusion list for cell reselection of multicast services, a multicast exclusion list for cell reselection of multicast services, a list of neighboring cell information, applicability information of multicast configuration for neighboring cells, neighboring cell multicast configuration, cell status indication for multicast reception, cell reservation indication for multicast reception, cell reselection priority, or priority of frequency for cell reselection.

[0256] According to an embodiment, the MBS multicast service controller (140) may be configured to handle multicast reception of the UE (100) based on the received at least one message.

[0257] According to an embodiment, a user equipment (UE) (100) may be provided.

[0258] According to an embodiment, the UE (100) may include a processor (110); a memory (130); and an MBS multicast service controller (140) coupled to the processor (110) and the memory (130).

[0259] According to an embodiment, the MBS multicast service controller (140) may be configured to receive a radio resource control (RRC) release with a suspension configuration.

[0260] According to an embodiment, the MBS multicast service controller (140) may be configured to receive a deprioritization request for a multicast configuration.

[0261] According to an embodiment, the MBS multicast service controller (140) may be configured to store a deprioritization request for the multicast configuration.

[0262] According to an embodiment, the MBS multicast service controller (140) may be configured to start a timer.

[0263] According to an embodiment, the MBS multicast service controller (140) may be configured to maintain the deprioritization request for the multicast configuration until a timer expires or a release of the deprioritization request for the multicast configuration is received.

[0264] According to an embodiment, the MBS multicast service controller (140) may be configured to perform cell reselection under RRC inactivation.

[0265] According to an embodiment, the MBS multicast service controller (140) may be configured to consider the current frequency or the frequency indicated in the stored deprioritization request for the multicast configuration as the lowest priority.

[0266] According to an embodiment, a network device (200) may be provided.

[0267] According to an embodiment, the network device (200) may include a processor (210); a memory (230); and an MBS multicast service controller (240) coupled to the processor (210) and the memory (230).

[0268] According to an embodiment, an MBS multicast service controller (240) may be configured to send at least one message supporting a mobility scenario of a user equipment (UE) (100) in an RRC inactive state to the UE (100).

[0269] According to an embodiment, at least one message may include at least one of the following: multicast service coverage information supporting the mobility of the UE (100), a multicast inclusion list for cell reselection of the multicast service, a multicast exclusion list for cell reselection of the multicast service, a list of neighboring cell information, applicability information of the multicast configuration of a service cell for at least one neighboring cell, a neighboring cell multicast configuration, a cell status indication for multicast reception, a cell reservation indication for multicast reception, a cell reselection priority, or a priority of a frequency for cell reselection.

[0270] According to an embodiment, the MBS multicast service controller (240) may be configured to handle multicast reception of the UE (100) based on at least one message.

[0271] The various actions, actions, blocks, steps, etc. in the flow charts (400 and 700) may be performed in the order presented, in a different order, or simultaneously. In addition, in some embodiments, some of the actions, actions, blocks, steps, etc. may be omitted, added, modified, skipped, etc. without departing from the scope of the present disclosure.

[0272] 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 an element. The element may be at least one of a hardware device or a combination of a hardware device and a software module.

[0273] The foregoing description of specific embodiments will fully reveal the general nature of the embodiments herein so that others can easily modify and / or adjust such specific embodiments for various applications by applying current knowledge without departing from the general concepts, and therefore, such adjustments and modifications should and are intended to be understood as being within the meaning and scope of equivalents of the disclosed embodiments. It should be understood that the wording or terminology employed herein is for descriptive and not limiting purposes. Therefore, although the embodiments herein have been described according to at least one embodiment, those skilled in the art will recognize that the embodiments herein can be practiced by modification within the spirit and scope of the embodiments as described herein.

Claims

1. A method performed by a user equipment (UE) in a communication system, the method comprising: identifying frequency information associated with multicast broadcast service (MBS) service continuity in a radio resource control (RRC) inactive state; performing cell reselection based on the frequency information; as well as It is identified whether a reselected cell through the cell reselection is available for MBS multicast reception.

2. The method according to claim 1, further comprising: In a case where the reselected cell is available for the MBS multicast reception: receiving the MBS multicast reception from the reselected cell in the RRC inactive state.

3. The method according to claim 1, further comprising: In the case that the reselected cell is not available for the MBS multicast reception: Transition to RRC connected state; as well as The MBS multicast reception is received in the RRC connected state.

4. The method according to claim 1, wherein: The MBS multicast reception is an MBS multicast reception to be received by the UE or to be continued to be received by the UE.

5. The method according to claim 1, wherein: The frequency information includes frequency prioritization for the MBS multicast reception.

6. The method according to claim 1, wherein: The frequency information includes a first frequency list and a second frequency list, wherein MBS multicast is available on the first frequency list and the MBS multicast is not available on the second frequency list, and The reselected cell corresponds to the frequency included in the first list.

7. The method according to claim 1, wherein: The frequency information is obtained via broadcast signaling or dedicated signaling.

8. A user equipment (UE) in a communication system, the UE comprising: Transceiver; as well as A processor is coupled to the transceiver and is configured to: identifying frequency information associated with multicast broadcast service (MBS) service continuity in a radio resource control (RRC) inactive state; performing cell reselection based on the frequency information; and It is identified whether a reselected cell through the cell reselection is available for MBS multicast reception.

9. The UE according to claim 8, wherein: The processor is further configured to: if the reselected cell is available for the MBS multicast reception: receive the MBS multicast reception from the reselected cell in the RRC inactive state.

10. The UE according to claim 8, wherein: The processor is further configured to: In the case that the reselected cell is not available for the MBS multicast reception: Transition to the RRC Connected state; and The MBS multicast reception is received in the RRC connected state.

11. The UE according to claim 8, wherein: The MBS multicast reception is an MBS multicast reception to be received by the UE or to be continued to be received by the UE.

12. The UE according to claim 8, wherein: The frequency information includes frequency prioritization for the MBS multicast reception.

13. The UE according to claim 8, wherein: The frequency information includes a first frequency list and a second frequency list, wherein MBS multicast is available on the first frequency list and the MBS multicast is not available on the second frequency list, and The reselected cell corresponds to the frequency included in the first list.

14. A method performed by a base station in a communication system, the method comprising: sending information associated with frequency information to a user equipment (UE), wherein the frequency information is associated with multicast broadcast service (MBS) service continuity in a radio resource control (RRC) inactive state; as well as In a case where a cell associated with the frequency information is available for MBS multicast transmission, providing the MBS multicast transmission to the UE in the RRC inactive state on the cell.

15. A base station in a communication system, the base station comprising: Transceiver; as well as A processor is coupled to the transceiver and is configured to: transmitting information associated with frequency information to a user equipment (UE), wherein the frequency information is associated with multicast broadcast service (MBS) service continuity in a radio resource control (RRC) inactive state; and In a case where a cell associated with the frequency information is available for MBS multicast transmission, providing the MBS multicast transmission to the UE in the RRC inactive state on the cell.

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