Cell reselection method for MBS service continuity, method for providing MBS service continuity and related equipment

Abstract

The invention provides a cell reselection method for multicast and / or broadcast service (MBS) service continuity and related equipment. The method is executed by user equipment (UE), and comprises the following steps: staying on a first cell for MBS data reception based on MBS configuration in a power saving state; receiving signaling from at least one of the first cell and the at least one neighboring cell to cause the energy-saving UE to prioritize the plurality of cells for cell reselection, where the MBS indication included in the signaling is configured to identify whether the MBS session of the associated cell is activated; and selecting a second cell from the at least one adjacent cell based on the MBS indication, and changing from the first cell to residing in the second cell for MBS data reception. By this method, MBS service continuity is achieved during a serving cell change.

Description

Technical Field

[0001] The present application relates to the field of wireless communication technology, and in particular to a cell reselection method for multicast and / or broadcast service (MBS), a method for providing MBS service continuity, and related devices. Background Art

[0002] Communication systems and networks have evolved towards broadband mobile systems. In the cellular wireless communication system developed by the Third Generation Partnership Project (3GPP), User Equipment (UE) is connected to the Radio Access Network (RAN) via a radio link. The RAN includes a set of base stations that provide radio links to UEs located in the cells covered by the base stations and an interface to the Core Network (CN), which has the function of controlling the entire network. It is understood that the RAN and CN each perform corresponding functions related to the entire network. 3GPP has developed the so-called Long Term Evolution (LTE) system, namely the Evolved Universal Mobile Telecommunications System Area Radio Access Network (E-UTRAN), for a mobile access network of one or more macro-cells supported by base stations called eNodeB or eNB (evolved NodeB). Recently, LTE has further evolved into the so-called 5G or New Radio (NR) system, in which one or more cells are supported by base stations called gNB.

[0003] In LTE, if the UE is inactive for a period of time, the network can command the UE to enter the RRC_IDLE state, which is to reduce the power consumption of the UE. Whenever the UE needs to perform certain activities, the UE needs to transition from the RRC_IDLE state to the RRC_CONNECTED state. In current mobile communication applications, a small amount of data must be sent frequently, so the frequent transition between idle and connected states increases the network signaling burden and delay. Therefore, 5G NR defines a new state called RRC_INACTIVE to reduce the network signaling burden and delay caused by the transition to the RRC_CONNECTED state. In NR, when an RRC connection is established, the UE is in the RRC_CONNECTED state, and when the RRC connection is suspended, the UE is in the RRC_INACTIVE state. If these are not the cases, the UE is in the RRC_IDLE state, that is, the RRC connection is not established. The RRC_INACTIVE state and the RRC_IDLE state can be called power saving states. More specifically, in the RRC_INACTIVE state, the UE access stratum (AS) context is stored on the UE side and the network side, thereby maintaining the connection with the core network (i.e., the UE remains in the CM-CONNECTED state (CM is the abbreviation of Connection Management) and disconnecting from the radio access network (RAN). The network can contact the inactive UE through RAN or CN paging information.

[0004] Broadcast / Multicast Services (MBS) are not yet standardized in the first two new radio releases of the specifications (i.e., 3GPP Rel-15 and Rel-16). Nevertheless, MBS may still provide substantial improvements in system efficiency and user experience for some important use cases (e.g., but not limited to, public safety and mission-critical, V2X applications, transparent IPv4 / IPv6 through multicast delivery, IPTV, software delivery over the air, group communications, and IoT applications).

[0005] In order to make it possible to deliver multicast / broadcast services with efficient resources, 3GPP has developed NR Multicast and / or Broadcast Service (NR MBS) in Rel-17 version, with Single-Cell Point-to-Multipoint (SC-PTM) technology defined in LTE as the baseline. In 3GPP Rel-17 version, NG-RAN only formulates multicast for multiple UEs in RRC_CONNECTED state, which may not fully meet requirements such as mission-critical services, especially for cells with a large number of UEs. In addition, it is not power-saving for the UE to always remain in RRC_CONNECTED state. If the UE transitions to RRC_INACTIVE state to save power and then returns to RRC_CONNECTED state to receive MBS, such severe service delay may become a problem. Therefore, it is very important to provide multicast support for multiple UEs in RRC_INACTIVE state. In addition, when the RRC_INACTIVE UE moves across cells (i.e., leaves the transmission coverage of the MBS session area), the non-negligible service delay caused by the change of cells will be aggravated. Therefore, how to reduce the delay of cell reselection to improve MBS service continuity is a key research topic in this field. Summary of the invention

[0006] The present disclosure can improve the latency of MBS data transmission during the service cell change and achieve the continuity of MBS service.

[0007] In a first aspect, the present application provides a cell reselection method for multicast and / or broadcast service (MBS) service continuity, which is performed by an energy-saving user equipment UE, and includes: in a power saving state, based on the MBS configuration, staying on a first cell to receive MBS data; receiving signaling from at least one of the first cell and at least one neighboring cell so that the energy-saving UE prioritizes multiple cells for cell reselection, wherein the MBS indication contained in the signaling is configured to identify whether the MBS session of the associated cell is activated; and selecting a second cell from the at least one neighboring cell based on the MBS indication, and changing from the first cell to reside in the second cell to receive the MBS data.

[0008] Optionally, if the MBS indication is set to a value, the MBS session of the associated cell is deactivated, and if the MBS indication is set to another value different from the one value, the MBS session of the associated cell is activated to perform MBS in the power saving state.

[0009] Optionally, a neighboring cell with an activated MBS session is preferentially selected as the second cell.

[0010] Optionally, the UE further selects the second cell based on detecting at least one of a new cell identifier and an MBS temporary mobile group identity (TMGI).

[0011] Optionally, the MBS indication is further configured to identify at least one of a point-to-multipoint PTM transmission mode and a point-to-point PTP transmission mode supported by the associated cell to transmit MBS data.

[0012] Optionally, if the MBS indication is set to a first value, the PTM transmission mode is supported, if the MBS indication is set to a second value, the PTP transmission mode is supported, and if the MBS indication is set to a third value, both the PTM transmission mode and the PTP transmission mode are supported.

[0013] Optionally, a neighboring cell that supports the same transmission mode as the transmission mode previously used by the UE is preferentially selected as the second cell.

[0014] Optionally, the method further comprises:

[0015] An indication is received to indicate whether a transmission mode used by the first cell to transmit MBS data is the same as that of the at least one neighboring cell.

[0016] Optionally, a neighboring cell having the same PTM configuration as the first cell is preferentially selected as the second cell.

[0017] Optionally, during cell reselection, a neighboring cell having an activated MBS session and having the same PTM configuration as the first cell is first selected as the second cell.

[0018] Optionally, the method further comprises:

[0019] An indication is received to indicate whether the PTM configuration used by the UE to receive MBS data from the first cell is the same as that of the at least one neighboring cell.

[0020] Optionally, the UE receives MBS data from the second cell without performing a state transition.

[0021] Optionally, the MBS configuration includes neighboring cell information that can be directly used by the UE for cell reselection.

[0022] Optionally, all suitable cells provided in the stored neighboring cell information are cells that can provide MBS control and data channels to continue MBS data transmission via at least one of PTM and PTP transmission modes.

[0023] Optionally, when the UE camps on the second cell, the UE directly applies the stored MBS configuration for the first cell to perform the MBS data reception.

[0024] Optionally, a cell that can accept MBS is selected as the second cell where the UE resides, and the cell that can accept MBS is a cell that provides MBS control and data channels to continue MBS data transmission through at least one of PTM and PTP transmission modes.

[0025] Optionally, the method further comprises:

[0026] The UE sends at least one of an MBS preamble and an MBS system information SI request to request to join the ongoing MBS session and establish an associated MBS packet data unit PDU session.

[0027] Optionally, the method further comprises:

[0028] The UE sends an MBS data request via a random access (RA) procedure or an MBS tracking area update to request to join the ongoing MBS session.

[0029] Optionally, if an MBS indication indicating a cell associated with a deactivated MBS session is detected, the method further comprises:

[0030] The UE sends at least one of an MBS preamble and an MBS system information SI request to activate the MBS session and establish an associated MBS packet data unit PDU session.

[0031] Optionally, if an MBS indication indicating a cell associated with a deactivated MBS session is detected, the method further comprises:

[0032] The UE sends an MBS data request via a random access (RA) procedure or an MBS tracking area update to request activation of the MBS session.

[0033] Optionally, if only a non-MBS acceptable cell is detected, the UE camps on the non-MBS acceptable cell, where the non-MBS acceptable cell is a cell that provides MBS data in a unicast manner when the UE is in a non-power saving state.

[0034] Optionally, the method further comprises:

[0035] The UE receives downlink control information DCI carrying scheduling information of the MBS data.

[0036] Optionally, during transmission of the MBS configuration, MBS data or paging, at least one of an association identifier and a parameter of a radio access network RAN ​​function split node providing a cell is used.

[0037] A second aspect of the present application provides a method for providing multicast and / or broadcast service MBS service continuity, which is performed by a network node in a network, and includes: sending signaling to an energy-saving user equipment UE so that the UE prioritizes multiple cells for cell reselection, wherein the MBS indication contained in the signaling is configured to identify whether the MBS session of the associated cell is activated, so that the UE decides whether to change from the serving cell to reside in the associated cell for MBS data reception.

[0038] Optionally, if the MBS indication is set to a value, the MBS session of the associated cell is deactivated, and if the MBS indication is set to another value different from the one value, the MBS session of the associated cell is activated to enable the UE in the power saving state to perform MBS.

[0039] Optionally, if the MBS indication indicates that the associated cell has an activated MBS session, the associated cell is preferentially selected by the UE for cell reselection.

[0040] Optionally, the MBS indication is further configured to identify at least one of a point-to-multipoint PTM transmission mode and a point-to-point PTP transmission mode supported by the associated cell to transmit MBS data.

[0041] Optionally, if the MBS indication is set to a first value, the PTM transmission mode is supported, if the MBS indication is set to a second value, the PTP transmission mode is supported, and if the MBS indication is set to a third value, both the PTM transmission mode and the PTP transmission mode are supported.

[0042] Optionally, if the MBS indication indicates that the transmission mode supported by the associated cell is the same as the transmission mode previously used by the UE, the UE preferentially selects the associated cell for cell reselection.

[0043] Optionally, the method further comprises:

[0044] An indication is sent to indicate that the serving cell uses the same transmission mode as the associated cell to transmit MBS data.

[0045] Optionally, if the associated cell has the same PTM configuration as the serving cell, the UE preferentially selects the associated cell for cell reselection.

[0046] Optionally, if the associated cell has the same activated MBS session and PTM configuration as the serving cell, the UE preferentially selects the associated cell for cell reselection.

[0047] Optionally, the method further comprises:

[0048] An indication is sent to indicate whether the PTM configuration used by the UE to receive MBS data from the serving cell is the same as that of the associated cell.

[0049] Optionally, the network node shares the same PTM configuration with other network nodes in the network.

[0050] Optionally, the method further comprises:

[0051] The MBS data is received from the core network through a shared MBS transmission or a separate MBS transmission.

[0052] Optionally, the method further comprises:

[0053] Neighboring cell information that can be directly applied by the UE for cell reselection is sent to the UE.

[0054] Optionally, the neighboring cell information includes suitable cells, and all suitable cells are cells that can provide MBS control and data channels to continue MBS data transmission via at least one of PTM and PTP transmission modes.

[0055] Optionally, the sent signaling indicates that the MBS indication exists, which indicates that the associated cell is a cell that can accept MBS, and the cell that can accept MBS is a cell that provides MBS control and data channels to continue MBS data transmission through at least one of PTM and PTP transmission methods.

[0056] Optionally, the method further comprises:

[0057] At least one of an MBS preamble and an MBS system information (SI) request is received by the network node from the UE, requesting to join the ongoing MBS session and establish an associated MBS packet data unit (PDU) session.

[0058] Optionally, the method further comprises:

[0059] An MBS data request sent via a random access (RA) procedure or an MBS tracking area update is received by the network node, requesting to join the ongoing MBS session.

[0060] Optionally, if the MBS indication indicates the associated cell having a deactivated MBS session, the method further comprises:

[0061] At least one of an MBS preamble and an MBS system information (SI) request is received by the network node from the UE, requesting to activate the MBS session and establish an associated MBS packet data unit (PDU) session.

[0062] Optionally, if the MBS indication indicates the associated cell having a deactivated MBS session, the method further comprises:

[0063] An MBS data request sent via a random access (RA) procedure or an MBS tracking area update is received by the network node from the UE, requesting activation of the MBS session.

[0064] Optionally, the sent signaling does not indicate the MBS indication, which indicates that the associated cell is a cell that is not MBS acceptable, and the cell that is not MBS acceptable is a cell that provides MBS data in a unicast manner when the UE is in a non-power saving state.

[0065] Optionally, the method further comprises:

[0066] The network node sends downlink control information DCI carrying scheduling information of the MBS data to the UE.

[0067] Optionally, during transmission of the MBS configuration, MBS data or paging, at least one of an association identifier and a parameter of a split node is split using a radio access network RAN ​​function.

[0068] A third aspect of the present application provides a user device, which includes a memory and a processor coupled to the memory, and the processor is configured to call and run program instructions stored in the memory to execute the above method.

[0069] A fourth aspect of the present application provides a base station, which includes a memory and a processor coupled to the memory, and the processor is configured to call and run program instructions stored in the memory to execute the above method.

[0070] A fifth aspect of the present application provides a non-transitory machine-readable storage medium having instructions stored thereon, which, when executed by a computer, causes the computer to execute the above method.

[0071] The sixth aspect of the present application provides a chip, which includes: a processor configured to call and run a computer program stored in a memory, so that a device equipped with the chip executes the above method.

[0072] In a seventh aspect of the present application, a computer-readable storage medium stores a computer program, wherein the computer program enables a computer to execute the above method.

[0073] In an eighth aspect of the present application, a computer program product comprises a computer program, wherein the computer program enables a computer to execute the above method.

[0074] The ninth aspect of the present application is a computer program, wherein the computer program enables a computer to execute the above method. BRIEF DESCRIPTION OF THE DRAWINGS

[0075] In order to more clearly illustrate the embodiments of the present application or related technologies, the following figures will be described in the embodiments and briefly introduced as follows. It is obvious that these figures only present some embodiments of the present disclosure, and ordinary technicians in this field can derive other figures based on these figures without making any assumptions.

[0076] Figure 1a A schematic diagram showing a communication control system according to an embodiment of the present application.

[0077] Figure 1b A block diagram of a base station performing wireless communication in a communication control system according to an embodiment of the present application is shown.

[0078] Figure 2a Diagram showing the user plane radio protocol architecture for NR MBS in gNB and UE.

[0079] Figure 2b A schematic diagram showing that the gNB further includes a centralized unit (CU) and multiple distributed units (DU).

[0080] Figure 3 Shows an overview of the Radio Resource Control (RRC) state transitions of a UE in NR.

[0081] Figure 4a A flowchart of a cell reselection method for MBS service continuity performed by a user equipment according to an embodiment of the present application is shown.

[0082] Figure 4b A flowchart of a method for providing MBS service continuity performed by a network node according to an embodiment of the present application is shown.

[0083] Figure 5A flowchart showing an MBS-enabled UE(s) manually reselecting a new suitable cell with an activated shared MBS transmission mode between NG-RAN nodes according to the first embodiment of the present application.

[0084] Figure 6 A flow chart showing an MBS-enabled UE(s) manually reselecting a new MBS-acceptable cell with an activated shared MBS transmission mode between NG-RAN nodes according to the second embodiment of the present application.

[0085] Figure 7 A flowchart showing that an MBS-enabled UE(s) manually reselects a new MBS-acceptable cell with an activated shared MBS transmission mode between NG-RAN nodes in the RRC_INACTIVE state according to the third embodiment of the present application.

[0086] Figure 8 A flow chart showing an MBS-enabled UE(s) manually reselecting a new MBS-acceptable cell with a separate MBS transmission mode and an activated shared MBS transmission mode between NG-RAN nodes according to a fourth embodiment of the present application.

[0087] Fig. 9 A flowchart showing an MBS-enabled UE(s) manually reselecting a new non-acceptable MBS cell with a separate MBS transmission mode and an activated shared MBS transmission mode between NG-RAN nodes according to the fifth embodiment of the present application.

[0088] Fig.10 A flowchart showing an MBS-enabled UE(s) manually reselecting a new suitable cell with a deactivated shared MBS transmission mode between NG-RAN nodes according to a sixth embodiment of the present application.

[0089] Fig.11 A flowchart showing an MBS-enabled UE(s) manually reselecting a new MBS-acceptable cell with a deactivated shared MBS transmission mode between NG-RAN nodes according to the seventh embodiment of the present application.

[0090] Fig.12 A flowchart showing that an MBS-enabled UE(s) manually reselects a new MBS-acceptable cell with a deactivated shared MBS transmission mode between NG-RAN nodes in the RRC_INACTIVE state according to the eighth embodiment of the present application.

[0091] Fig.13A flowchart showing an MBS-enabled UE(s) manually reselecting a new MBS-acceptable cell with a separate MBS transmission mode and a deactivated shared MBS transmission mode between NG-RAN nodes according to the ninth embodiment of the present application. DETAILED DESCRIPTION

[0092] The following will be combined with the accompanying drawings to describe the embodiments of the present disclosure in detail in terms of technical solutions, structural features, objectives and effects achieved. Specifically, the terms in the embodiments of the present disclosure are only used to describe certain embodiments and are not used to limit the present disclosure.

[0093] As used herein, the term " / " should be interpreted as meaning "and / or". In addition, combinations such as "at least one of A, B, or C", "one or more of A, B, or C", "at least one of A, B and C", "one or more of A, B, or C", or "A, B and / or C" may be only A, only B, only C, A and B, A and C, B and C, or A, B, and C, wherein any of the above combinations may include one or more members of A, B, or C.

[0094] It should be noted that, unless otherwise explicitly stated, the description in this application of UE manually performing cell reselection, wherein "manually" does not mean that the UE user manually performs the cell reselection operation, but emphasizes that whether to perform the cell reselection operation is mainly determined by the UE.

[0095] Figure 1a and Figure 1b The schematic diagram and functional block diagram of the communication control system 1 according to the present application are respectively shown. The communication control system 1 includes a user device 10 and a base station (which is a network node, such as an NG-RAN node) 20. The user device 10 and the base station 20 can communicate with each other wirelessly or by wire. The base station 20 and the next generation core network 30 can also communicate with each other wirelessly or by wire. When the communication control system 1 complies with the New Radio (NR) standard of the 3rd Generation Partnership Project (3GPP), the next generation core network (5GCN) 30 is a backend service network system and may include an access and mobility management function (AMF) network element, a user plane function (UPF) network element, and a session management function (SMF) network element.

[0096] The user equipment 10 may be an MBS-enabled or MBS-supporting device, but the present application is not limited thereto. The user equipment 10 includes a transceiver 12 and a processor 14 electrically connected to each other. The base station 20 includes a transceiver 22 and a processor 24 electrically connected to each other. The transceiver 12 of the user equipment 10 is used to send a signal to the base station 20 (and receive a signal from the base station 20), and the processor 24 of the base station 20 processes the signal. The transceiver 22 of the base station 20 is used to send a signal to the user equipment 10 (and receive a signal from the user equipment 10), and the processor 14 of the user equipment 10 processes the signal. In this way, the user equipment 10 and the base station 20 communicate with each other.

[0097] In 5G, the multicast and broadcast service (NR MBS) of the new radio technology supports point-to-multipoint transmission within a cell (i.e., single cell-point to multipoint (SC-PTM)). Figure 2 shows the user plane radio protocol architecture between the base station (gNB) and the UE for NR MBS, which includes the Service Data Adaptation Protocol (SDAP), the Packet Data Convergence Protocol (PDCP), the Radio Link Control (RLC), and the Medium Access Control (MAC). In NR, if an MBS session can be mapped to multiple 5G MBS QoS flows, these NR MBS QoS flows will be mapped to NR MBS radio bearers through NRSDAP. In the case of RAN functional split, the gNB may also include a centralized unit (CU) and multiple distributed units (DU), such as Figure 2b As shown in FIG. 1 , the protocol stack of the CU includes the RRC layer, the SDAP layer and the PDCP layer, while the protocol stack of the DU includes the RLC layer, the MAC layer and the PHY layer. An F1 interface located between the CU and the DU is established between the PDCP layer of the protocol stack and the RLC layer of the protocol stack.

[0098] Figure 3An overview of the Radio Resource Control (RRC) state transitions of a UE in NR is shown. When an RRC connection has been established, the UE is either in the RRC_CONNECTED state or in the RRC_INACTIVE state. In the RRC_CONNECTED state, the UE joins an MBS session identified by the associated MBS session ID (e.g., Temporary Mobile Group Identity, TMGI). The NR MBS configuration is periodically transmitted over the MBS Control Channel (MCCH), and the UE(s) applies the received NR MBS configuration over this channel in order to receive MBS data over the MBS Traffic Channel (MTCH). In some cases, neighbor cell information (e.g., MBS indication, PTM configuration) that the UE can directly apply for cell reselection is included in the NR MBS configuration to achieve MBS service continuity. If the UE supports MBS reception (i.e., multicast and / or broadcast reception) in the RRC_INACTIVE state, the network and the UE store the UE context for multicast and / or broadcast services to reduce power consumption. The stored UE context may include the MBS sessions of interest to the UE and / or previously used NR MBS configurations. The network can identify which UE is interested in the MBS session from the MBS context in the UE context. In addition, the network provides additional information to the UE in the RRC_INACTIVE state. If the configuration used in the RRC_INACTIVE state is a separate configuration, the UE can receive dedicated signaling (e.g., RRCRelease) carrying the NR MBS configuration (e.g., MBS session ID, G-RNTI, G-CS-RNTI, PTM / PTP configuration of MRB, supported frequencies, scheduling information of MTCH, DRX of MBS, HARQ configuration, MBS indication, etc.) and resume the RRC connection if necessary. After successfully receiving the NR MBS configuration, the UE can transition to the RRC_INACTIVE state to receive MBS data. If the RRC connection is released, the UE transitions to the RRC_IDLE state.

[0099] From the core network (5GCN) perspective, two methods for delivering MBS sessions are defined:

[0100] Shared MBS transmission method: 5GCN receives one copy of multiple MBS packets and transmits one copy of these MBS packets to the NG-RAN node, which then transmits these packets to one or more UEs. This means that only NG-RAN nodes that support MBS functions can receive MBS data through this shared MBS transmission method. This method is used to save 5GCN resources for MBS data transmission.

[0101] Individual MBS transmission: 5GCN receives one copy of multiple MBS packets and transmits individual copies of these MBS packets to each UE via a PDU session per UE. This is used when the NG-RAN node does not support MBS functionality but still requires MBS data due to manual cell reselection (e.g., change of serving cell, mobility scenario).

[0102] From the perspective of the Radio Access Network (i.e., NG-RAN, e.g., gNB, cell), upon receiving MBS data from 5GCN, the NG-RAN node will deliver the MBS data to the UE(s). The NG-RAN node may use one or more Multicast Radio Bearers (MRBs) for MBS data transmission. Each MRB is divided into point-to-multipoint (PTM) and point-to-point (PTP) branches. This means that the MBS data can be transmitted via PTM or PTP transmission mode. The transmission mode will be decided by the NG-RAN node based on the network conditions (e.g., QoS requirements, number of served / interested UEs, unicast / MBS traffic load, UE location, channel state information, etc.). The PTM configuration is transmitted to the UE in RRC_CONNECTED / RRC_INACTIVE / RRC_IDLE state via dedicated signaling (e.g., RRCReconfiguration, RRCRelease, Paging). During cell reselection, there may be a situation where neighboring NG-RAN nodes share the same PTM configuration over the backhaul interface or Uu interface to achieve MBS service continuity. To reduce signaling overhead, there may be at least one bit in the dedicated signaling (e.g., RRCReconfiguration, RRCRelease, Paging) to indicate whether the PTM configuration is the same as one or more neighboring NG-RAN nodes.

[0103] Considering the power efficiency and mobility of the UE, the serving NG-RAN node provides the NR MBS / PTM configuration (e.g., through system information, MCCH, dedicated RRC signaling), which optionally includes neighboring cell (i.e., suitable cell) information, which the UE can directly apply for cell reselection. Continuous MBS will be provided by the suitable cell without the need for the UE to perform state transition. When the UE moves from the serving NG-RAN node to a new NG-RAN node, the NR MBS configuration may be updated in the new NG-RAN node (which is a cell that supports MBS). NG-RAN nodes can be classified according to whether they provide MBS transmission mode:

[0104] MBS acceptable cells: MBS acceptable cells are cells on which the UE can camp to obtain MBS data through shared MBS transmission mode. Such cells should provide MBS control and data channels to continue MBS transmission through PTM and / or PTP transmission mode. An MBS indication (for example, transmitted in system information, MCCH, paging, NAS signaling) is required to identify such activated / deactivated MBS cells and for the UE to perform manual cell reselection. In some cases, this MBS indication can be used to identify PTM and / or PTP transmission mode. In some cases, the UE may want to select the same PTM configuration when the cell changes. Suitable cells provided in the stored NR MBS configuration are usually MBS acceptable cells.

[0105] Non-MBS Acceptable Cell: A non-MBS acceptable cell is a cell where the UE can camp to obtain MBS data through a separate MBS transmission method. Such a cell can provide MBS data through unicast when the UE is in the RRC_CONNECTED state.

[0106] An MBS-enabled UE shall monitor group notifications (e.g., system information, paging notifications), MCCH / MTCH channels for the reception of MBS data when joining at least one MBS session. An MBS-enabled UE needs to continuously receive MBS data when changing one or more of its serving cells. In this case, the UE may manually select or reselect a new cell based on the detection of a new cell identifier, an MBS session identifier (e.g., TMGI) and / or an MBS indication. The detection of a new cell identifier may be used to identify whether it is a suitable cell. The detected new MBS session identifier may be used to identify whether it is a cell that can accept MBS and the MBS session it provides. The MBS indication may be used by the UE to determine the priority of which cell it should immediately camp on. For example, but not limited to, the MBS indication is a bit transmitted in a group notification (e.g., system information, paging) to identify whether the cell is a cell that can accept MBS and whether the MBS session is activated. If the MBS indication is set to 0, it means that the MBS session of the cell that can accept MBS has been deactivated. The UE shall send a request to activate the MBS session. If the MBS indication is set to 1, it indicates that the MBS session of the cell that can accept MBS has been activated for MBS in the RRC_INACTIVE state. If the MBS indication does not exist, it indicates that it is a cell that does not accept MBS. Based on the received MBS indication, the UE can give priority to cells with activated suitable / acceptable MBS with the same PTM configuration during cell reselection. In other cases, the MBS indication is more than 1 bit (e.g., 2 bits) sent in a group notification (e.g., system information, paging) to identify whether the MBS session is supported by PTM and / or PTP transmission modes. If the MBS indication is set to 00, it indicates that the MBS session of the cell that can accept MBS has been deactivated. When the MBS indication is set to 01 and 10, it indicates that one of PTM and PTP is supported respectively. If the MBS indication is set to 11, it indicates that the cell that can accept MBS supports both PTM and PTP transmission modes. The UE can preferentially reside on a cell that supports the same transmission mode as the previously used transmission mode. If the UE selects the same PTM configuration between the serving cell and the new cell, this will help the UE to continuously receive MBS data. Based on the monitoring of group notifications (e.g., system information, paging) / MBS information from the serving cell and neighboring cells, if a suitable cell is detected, the UE can directly apply the stored neighboring cell information (e.g., NR MBS configuration) to monitor MBS information (e.g., MBS data, MBS paging notification). MBS data can be received without UE state transition. If a cell that can accept MBS is detected but it is not in the list of suitable cells, the UE can transition to the RRC_CONNECTED state or remain in the RRC_INACTIVE state to maintain MBS service continuity.In some cases, if only non-MBS acceptable cells are detected, the UE shall enter the RRC_CONNECTED state and establish a per-UE PDU session to receive MBS data. Non-MBS acceptable cells may provide the relevant MBS data to the UE(s) in a unicast manner.

[0107] Based on the above inventive concept, the present application provides a cell reselection method. Figure 4a 1 is a flowchart of a cell reselection method 100 for MBS service continuity performed by a user equipment according to an embodiment of the present application. The method 100 may include the following steps:

[0108] In step 110, the UE stays on the first cell for MBS data reception based on the MBS configuration in a power saving state (e.g., RRC_INACTIVE state and RRC_IDLE state). The first cell may be a serving cell serving the UE. The serving cell may configure the MBS configuration to the UE so that the UE may receive MBS data based on the MBS configuration. The UE may reselect a new cell in the power saving state for MBS data reception. At the same time, the UE changes from the first cell to the new cell for MBS data reception.

[0109] In step 120, the UE receives signaling from at least one of the first cell and at least one neighboring cell so that the energy-saving UE prioritizes multiple cells for cell reselection. This signaling includes an MBS indication, which is configured to identify whether the MBS session of the associated cell is activated. The MBS indication can be received from the first cell (serving cell) or the neighboring cell, or the first cell and the neighboring cell can send the MBS indication to the UE. Based on the MBS indication, the energy-saving UE can prioritize multiple cells for cell reselection. The MBS indication can be used to identify whether the MBS session of the associated cell is activated. If the MBS indication is received from the first cell, the associated cell can be any neighboring cell suitable for cell reselection by the power-saving UE. If the MBS indication is received from the neighboring cell, the associated cell can be the neighboring cell itself, and the MBS indication indicates whether this neighboring cell has an activated MBS session.

[0110] In one embodiment, if the MBS indication is set to a value (e.g., 0), the MBS session of the associated cell is deactivated, and if the MBS indication is set to another value different from the one value (e.g., 1), the MBS session of the associated cell is activated to perform MBS in a power saving state. A neighboring cell with an activated MBS session is preferentially selected as the second cell.

[0111] In one embodiment, the MBS indication is also configured to identify at least one of a point-to-multipoint PTM transmission mode and a point-to-point PTP transmission mode supported by the associated cell to transmit MBS data. In one example, if the MBS indication is set to a first value, the PTM transmission mode is supported, if the MBS indication is set to a second value, the PTP transmission mode is supported, and if the MBS indication is set to a third value, both the PTM transmission mode and the PTP transmission mode are supported. A neighboring cell that supports the same transmission mode as the transmission mode previously used by the UE is preferentially selected as the second cell. The method may further include: receiving an indication to indicate whether the transmission mode used by the first cell to transmit MBS data is the same as that of at least one neighboring cell.

[0112] In one embodiment, a neighboring cell having the same PTM configuration as the first cell is preferentially selected as the second cell. The method may further include: receiving an indication to indicate whether the PTM configuration used by the UE to receive MBS data from the first cell is the same as that of at least one neighboring cell. In one embodiment, during cell reselection, a neighboring cell having an activated MBS session and having the same PTM configuration as the first cell is first selected as the second cell.

[0113] In step 130, the UE selects a second cell from at least one neighboring cell based on the MBS indication, and changes from the first cell to camp on the second cell for MBS data reception. From the first cell to the second cell, MBS service continuity is still maintained. The UE may receive MBS data from the second cell with or without state transition. That is, the UE may transition from a power saving state (e.g., RRC_INACTIVE state) to a non-power saving state (e.g., RRC_CONNECTED) to receive MBS data from the second cell, or may stay in the power saving state to receive MBS data from the second cell.

[0114] In one embodiment, the MBS configuration includes neighboring cell information that the UE can directly use for cell reselection. All suitable cells provided in the stored neighboring cell information are cells that can provide MBS control and data channels to continue MBS data transmission via at least one of PTM and PTP transmission modes. In one embodiment, when the UE is camped on the second cell, the UE can directly apply the stored MBS configuration for the first cell for MBS data reception.

[0115] In one embodiment, a cell that can accept MBS is selected as a second cell where the UE resides, and the cell that can accept MBS is a cell that provides MBS control and data channels to continue MBS data transmission through at least one of PTM and PTP transmission modes. The method may further include: the UE sends at least one of an MBS preamble and an MBS system information SI request to request to join the ongoing MBS session and establish an associated MBS packet data unit PDU session. Alternatively, the method may further include: the UE sends an MBS data request via a random access RA procedure or an MBS tracking area update to request to join the ongoing MBS session.

[0116] In one embodiment, if an MBS indication indicating a cell associated with a deactivated MBS session is detected, the method further comprises: sending, by the UE, at least one of an MBS preamble and an MBS system information SI request to activate the MBS session and establish an associated MBS packet data unit PDU session. In one embodiment, if an MBS indication indicating a cell associated with a deactivated MBS session is detected, the method further comprises: sending, by the UE, an MBS data request via a random access RA procedure or an MBS tracking area update to request activation of the MBS session.

[0117] In one embodiment, if only non-MBS acceptable cells are detected, the UE resides on the non-MBS acceptable cells, the non-MBS acceptable cells being cells that provide MBS data in a unicast manner when the UE is in a non-power saving state. The method may further include: receiving, by the UE, downlink control information DCI with scheduling information of the MBS data.

[0118] By using the method 100 proposed above, based on the MBS indication, the power-saving UE can quickly reselect the cell without executing additional procedures to inquire whether the neighboring cell is a suitable cell. Therefore, the present invention can improve the delay of MBS data transmission during the serving cell switching and achieve the continuity of MBS service.

[0119] Based on the above inventive concept, the present application provides a method for providing MBS service continuity. Figure 4b A flowchart of a method 200 for providing MBS service continuity performed by a network node according to an embodiment of the present application is shown. The method 200 may include the following steps:

[0120] In step 210, a network node (e.g., a base station, a NG-RAN node) sends a signaling to an energy-saving user equipment UE so that the UE prioritizes multiple cells for cell reselection. This signaling includes an MBS indication, which is configured to identify whether the MBS session of the associated cell is activated, so that the UE decides whether to change from the serving cell to the associated cell for MBS data reception. The network node may be a serving cell that provides services to the UE, or may correspond to a neighboring cell of a neighboring UE. Based on the MBS indication, the energy-saving UE may prioritize multiple cells for cell reselection. The MBS indication may be used to identify whether the MBS session of the associated cell is activated. The associated cell may be any neighboring cell suitable for the power-saving UE to perform cell reselection, or may refer to a neighboring cell that sends signaling including the MBS indication. The MBS indication indicates whether the neighboring cell has an activated MBS session. This MBS indication may help the UE decide whether to change from the serving cell to the associated cell to reside in the associated cell to receive MBS data. For more details of method 200, reference may be made to the above method 100.

[0121] By using the method 200 proposed above, based on the MBS indication, the power-saving UE can quickly reselect the cell without executing additional procedures to inquire whether the neighboring cell is a suitable cell. Therefore, the present invention can improve the delay of MBS data transmission during the serving cell switching and achieve the continuity of MBS service.

[0122] Further details of the present invention are described below.

[0123] Figure 5A scenario is shown in which an MBS-enabled UE(s) manually reselects a new suitable cell with an activated shared MBS transmission mode between NG-RAN nodes according to the first embodiment of the present application. The UE is connected to the serving NG-RAN node to join at least one MBS session. The serving NG-RAN node as a cell that can accept MBS will decide the MBS bearer transmission mode (i.e., PTM and / or PTP) based on network conditions (e.g., QoS requirements, number of served / interested UEs, unicast / MBS traffic load, UE location, channel state information, etc.). If the UE obtains the NR MBS configuration of the serving NG-RAN node, it can receive MBS data in the RRC_CONNECTED state accordingly. In order to improve UE power efficiency, it is beneficial to enable MBS reception in the RRC_INACTIVE state. The NR MBS configuration used in the RRC_INACTIVE state can be the same as the configuration used in the RRC_CONNECTED state, or a different configuration can be used in the RRC_CONNECTED state. If the configuration used in the RRC_INACTIVE state is a separate configuration, the UE can receive dedicated signaling (e.g., RRCRelease) carrying the NR MBS configuration (e.g., including MBS session ID, G-RNTI, G-CS-RNTI, PTM / PTP configuration of MRB, scheduling information of MTCH, DRX of MBS, HARQ configuration, MBS indication, etc.) for MBS data reception. The provided NR MBS configuration optionally includes neighboring cell (e.g., suitable cell) information, which the UE can directly apply in cell reselection. When transitioning to the RRC_INACTIVE state, the 5GCN / network can identify which UE is interested in the MBS session from the MBS context in the stored UE context. The UE will continue to monitor MBS indications, group notifications and / or MBS associated information (e.g., in system information, paging) for MBS reception. During cell reselection, the UE may wish to select the same transport mode / bearer configuration based on the stored NR MBS configuration, as there may be situations where a neighboring NG-RAN node shares the same PTM configuration with the serving NG-RAN node via the backhaul interface or Uu interface for MBS service continuity. Upon receiving a group notification (e.g., system information, paging) from the serving cell and one or more neighboring cells, the UE will manually select or reselect a new NG-RAN node based on the detection of a new cell identifier, MBS session identifier (e.g., TMGI) and / or MBS indication. If an activated MBS indication of a suitable cell is detected and matches the UE's requirements (e.g., stored PTM configuration), the UE may manually reselect the suitable cell and directly apply the associated stored configuration to monitor the MBS information (e.g., NR MBS configuration, MBS paging notification) on the suitable cell.The UE can then receive MBS data without state transition. If necessary, a group notification with updated NR MBS configuration (e.g., by paging) can be sent on an MBS paging occasion / RAN paging cycle (not shown). Typically, manual cell reselection is based on the UE's configuration and associated MBS QoS requirements. The UE may give priority to an activated suitable cell with the same transmission mode / PTM configuration. The suitable cell will provide seamless MBS without the UE having to perform state transition.

[0124] Figure 6A scenario is shown in which an MBS-enabled UE(s) manually reselects a new MBS-acceptable cell with an activated shared MBS transmission mode between NG-RAN nodes according to the second embodiment of the present application. The UE is connected to the serving NG-RAN node to join at least one MBS session. The serving NG-RAN node as the MBS-acceptable cell will decide the MBS bearer transmission mode (i.e., PTM and / or PTP) based on network conditions (e.g., QoS requirements, number of served / interested UEs, unicast / MBS traffic load, UE location, channel state information, etc.). If the UE obtains the NR MBS configuration of the serving NG-RAN node, it can receive MBS data in the RRC_CONNECTED state accordingly. In order to improve UE power efficiency, it is beneficial to enable MBS reception in the RRC_INACTIVE state. The NR MBS configuration used in the RRC_INACTIVE state can be the same as the configuration used in the RRC_CONNECTED state, or a different configuration can be used in the RRC_CONNECTED state. If the configuration used in the RRC_INACTIVE state is a separate configuration, the UE may receive dedicated signaling (e.g., RRCRelease) carrying the NR MBS configuration (e.g., including MBS session ID, G-RNTI, G-CS-RNTI, PTM / PTP configuration of MRB, scheduling information of MTCH, DRX of MBS, HARQ configuration, etc.) for MBS data reception. The provided NR MBS configuration optionally includes neighboring cell (e.g., suitable cell) information, which the UE may directly apply in cell reselection. When transitioning to the RRC_INACTIVE state, the UE will continue to monitor MBS indications, group notifications and / or MBS associated information (e.g., in system information, paging) for MBS reception. During cell reselection, the UE may wish to select the same transport mode / bearer configuration based on the stored NR MBS configuration, because there may be a situation where a neighboring NG-RAN node shares the same PTM configuration with the serving NG-RAN node via the backhaul interface or Uu interface to achieve MBS service continuity. Upon receiving a group notification (e.g., system information, paging) from the serving cell and one or more neighboring cells, the UE will manually select or reselect a new NG-RAN node based on the detection of a new cell identifier, MBS session identifier (e.g., TMGI) and / or MBS indication. If an activated MBS indication is detected for an MBS-acceptable cell and the service (e.g., channel quality) is better than the serving NG-RAN node, the UE may manually reselect an MBS-acceptable cell and attempt to camp on it. The UE sends a preconfigured MBS preamble / MBS system information (SI) request to perform a dedicated RACH / on-demand SI and establish an associated MBS PDU session to join the ongoing MBS session.The 5GCN / network can identify which MBS session the UE is interested in from the MBS context in the stored UE context. In this way, the UE will transition to the RRC_CONNECTED state to connect with the new NG-RAN node. If a request to join an MBS session is received, the bearer selection may be redetermined and new MBS configuration and MBS data may be received accordingly. Typically, manual cell reselection is based on the UE's configuration and associated MBS QoS requirements. The UE may give priority to cells with activated acceptable MBS with the same transmission mode / PTM configuration. Cells that accept MBS can provide continuous MBS, which is triggered by the UE enabling MBS in the RRC_CONNECTED state.

[0125] Figure 7A scenario is shown in which an MBS-enabled UE(s) manually reselects a new MBS-acceptable cell with an activated shared MBS transmission mode between NG-RAN nodes in the RRC_INACTIVE state according to the third embodiment of the present application. The UE is connected to the serving NG-RAN node to join at least one MBS session. The serving NG-RAN node as the MBS-acceptable cell will decide the MBS bearer transmission mode (i.e., PTM and / or PTP) based on network conditions (e.g., QoS requirements, number of served / interested UEs, unicast / MBS traffic load, UE location, channel state information, etc.). If the UE obtains the NR MBS configuration of the serving NG-RAN node, it can receive MBS data in the RRC_CONNECTED state accordingly. In order to improve UE power efficiency, it is beneficial to enable MBS reception in the RRC_INACTIVE state. The NR MBS configuration used in the RRC_INACTIVE state can be the same as the configuration used in the RRC_CONNECTED state, or a different configuration can be used in the RRC_CONNECTED state. If the configuration used in the RRC_INACTIVE state is a separate configuration, the UE may receive dedicated signaling (e.g., RRCRelease) carrying the NR MBS configuration (e.g., including MBS session ID, G-RNTI, G-CS-RNTI, PTM / PTP configuration of MRB, scheduling information of MTCH, DRX of MBS, HARQ configuration, etc.) for MBS data reception. The provided NR MBS configuration optionally includes neighboring cell (e.g., suitable cell) information, which the UE may directly apply in cell reselection. When transitioning to the RRC_INACTIVE state, the UE will continue to monitor MBS indications, group notifications and / or MBS associated information (e.g., in system information, paging) for MBS reception. During cell reselection, the UE may wish to select the same transport mode / bearer configuration based on the stored NR MBS configuration, because there may be a situation where the neighboring NG-RAN node shares the same PTM configuration with the serving NG-RAN node via the backhaul interface or Uu interface to achieve MBS service continuity. Upon receiving a group notification (e.g., system information, paging) from the serving cell and one or more neighboring cells, the UE will manually select or reselect a new NG-RAN node based on the detection of a new cell identifier, MBS session identifier (e.g., TMGI) and / or MBS indication. If an activated MBS indication is detected for an MBS-acceptable cell and the service (e.g., channel quality) is better than that of the serving NG-RAN node, the UE may manually reselect an MBS-acceptable cell and attempt to camp on it. The UE sends an MBS data request (e.g., via 2 / 4 step RACH SDT, MBS tracking area update) to request to join an ongoing MBS session.The 5GCN / network can identify which MBS session the UE is interested in from the MBS context in the stored UE context. In this way, if necessary, the new NG-RAN node can redetermine the MBS bearer transmission mode (i.e., PTM and / or PTP) based on the UE request. Then, a group notification with an updated NR MBS configuration (e.g., by paging) can be sent on the MBS paging opportunity / RAN paging cycle. The UE can receive MBS data in the RRC_INACTIVE state accordingly. Typically, manual cell reselection is based on channel conditions and associated MBS QoS requirements. The UE can give priority to cells with activated acceptable MBS with the same transmission mode / PTM configuration. Cells that accept MBS can provide continuous MBS, which is triggered by the UE enabling MBS in the RRC_INACTIVE state.

[0126] Figure 8A scenario is shown in which an MBS-enabled UE(s) manually reselects a new MBS-acceptable cell with a separate MBS transmission mode and an activated shared MBS transmission mode between NG-RAN nodes according to the fourth embodiment of the present application. The UE is connected to the serving NG-RAN node to join at least one MBS session. The serving NG-RAN node as the cell that accepts MBS will decide the MBS bearer transmission mode (i.e., PTM and / or PTP) based on network conditions (e.g., QoS requirements, number of served / interested UEs, unicast / MBS traffic load, UE location, channel state information, etc.). If the UE obtains the NR MBS configuration of the serving NG-RAN node, it can receive MBS data in the RRC_CONNECTED state accordingly. In order to improve UE power efficiency, it is beneficial to enable MBS reception in the RRC_INACTIVE state. The NR MBS configuration used in the RRC_INACTIVE state can be the same as the configuration used in the RRC_CONNECTED state, or a different configuration can be used in the RRC_CONNECTED state. If the configuration used in the RRC_INACTIVE state is a separate configuration, the UE can receive dedicated signaling (e.g., RRCRelease) carrying the NR MBS configuration (e.g., including MBS session ID, G-RNTI, G-CS-RNTI, PTM / PTP configuration of MRB, scheduling information of MTCH, DRX of MBS, HARQ configuration, etc.) for MBS data reception. The provided NR MBS configuration optionally includes neighboring cell (e.g., suitable cell) information, which the UE can directly apply in cell reselection. When transitioning to the RRC_INACTIVE state, the 5GCN / network can identify which UE is interested in the MBS session from the MBS context in the stored UE context. The UE will continue to monitor MBS indications, group notifications and / or MBS associated information (e.g., in system information, paging) for MBS reception. During cell reselection, the UE may wish to select the same transport mode / bearer configuration based on the stored NR MBS configuration, as there may be situations where neighboring NG-RAN nodes share the same PTM configuration with the serving NG-RAN node via the backhaul interface or Uu interface for MBS service continuity. Upon receiving group notifications (e.g., system information, paging) from the serving cell and one or more neighboring cells, the UE will manually select or reselect a new NG-RAN node based on the detection of the new cell identifier, MBS session identifier (e.g., TMGI) and / or MBS indication. If no MBS indication is detected for a non-MBS acceptable cell, the UE may wish to skip camping on a candidate NG-RAN node and continue searching for a cell with an MBS acceptable as the new NG-RAN node.When an activated MBS acceptable cell is detected, the UE can manually reselect to camp on the cell. The operation of reselecting an activated MBS acceptable cell has been described in detail in the first to third embodiments above, so it will not be repeated here. Generally, the UE can give priority to activated suitable / acceptable MBS cells rather than non-acceptable MBS cells. Suitable / acceptable MBS cells can provide continuous MBS, which is triggered by the MBS-enabled UE.

[0127] Fig. 9A scenario is shown in which an MBS-enabled UE(s) manually reselects a new non-MBS-acceptable cell with a separate MBS transmission mode and an activated shared MBS transmission mode between NG-RAN nodes according to the fifth embodiment of the present application. The UE is connected to the serving NG-RAN node to join at least one MBS session. The serving NG-RAN node as a cell that accepts MBS will decide the MBS bearer transmission mode (i.e., PTM and / or PTP) based on network conditions (e.g., QoS requirements, number of served / interested UEs, unicast / MBS traffic load, UE location, channel state information, etc.). If the UE obtains the NR MBS configuration of the serving NG-RAN node, it can receive MBS data in the RRC_CONNECTED state accordingly. In order to improve UE power efficiency, it is beneficial to enable MBS reception in the RRC_INACTIVE state. The NR MBS configuration used in the RRC_INACTIVE state can be the same as the configuration used in the RRC_CONNECTED state, or a different configuration can be used in the RRC_CONNECTED state. If the configuration used in the RRC_INACTIVE state is a separate configuration, the UE may receive dedicated signaling (e.g., RRCRelease) carrying the NR MBS configuration (e.g., including MBS session ID, G-RNTI, G-CS-RNTI, PTM / PTP configuration of MRB, scheduling information of MTCH, DRX of MBS, HARQ configuration, etc.) for MBS data reception. The provided NR MBS configuration optionally includes neighboring cell (e.g., suitable cell) information, which the UE may directly apply in cell reselection. When transitioning to the RRC_INACTIVE state, the UE will continue to monitor MBS indications, group notifications and / or MBS associated information (e.g., in system information, paging) for MBS reception. During cell reselection, the UE may wish to select the same transport mode / bearer configuration based on the stored NR MBS configuration, because there may be a situation where the neighboring NG-RAN node shares the same PTM configuration with the serving NG-RAN node via the backhaul interface or Uu interface to achieve MBS service continuity. Upon receiving a group notification (e.g., system information, paging) from the serving cell and one or more neighboring cells, the UE will manually select or reselect a new NG-RAN node based on the detection of a new cell identifier, MBS session identifier (e.g., TMGI) and / or MBS indication. If a cell for which non-MBS is acceptable is detected and no MBS indication exists, the UE will attempt to camp on that cell. When the RACH procedure is triggered and each UE PDU session establishment is completed, the UE will transition to the RRC_CONNECTED state to request MBS data (e.g., via NAS signaling, RRC signaling).The 5GCN / network can identify that the UE is interested in the MBS session from the MBS context stored in the UE context. If the 5GCN accepts the transparent MBS data request, the new NG-RAN node will receive a single copy of multiple MBS packets from the 5GCN and transmit a separate copy of these MBS packets to the UE via each UE PDU session. Downlink control information (DCI) with MBS data scheduling information can be sent to the UE. Therefore, the UE will receive the MBS data in unicast mode.

[0128] Fig.10A scenario is shown in which an MBS-enabled UE(s) manually reselects a new suitable cell with a deactivated shared MBS transmission mode between NG-RAN nodes according to the sixth embodiment of the present application. The UE is connected to the serving NG-RAN node to join at least one MBS session. The serving NG-RAN node as a cell that can accept MBS will decide the MBS bearer transmission mode (i.e., PTM and / or PTP) based on network conditions (e.g., QoS requirements, number of served / interested UEs, unicast / MBS traffic load, UE location, channel state information, etc.). If the UE obtains the NR MBS configuration of the serving NG-RAN node, it can receive MBS data in the RRC_CONNECTED state accordingly. In order to improve UE power efficiency, it is beneficial to enable MBS reception in the RRC_INACTIVE state. The NR MBS configuration used in the RRC_INACTIVE state can be the same as the configuration used in the RRC_CONNECTED state, or a different configuration can be used in the RRC_CONNECTED state. If the configuration used in the RRC_INACTIVE state is a separate configuration, the UE may receive dedicated signaling (e.g., RRCRelease) carrying the NR MBS configuration (e.g., including MBS session ID, G-RNTI, G-CS-RNTI, PTM / PTP configuration of MRB, scheduling information of MTCH, DRX of MBS, HARQ configuration, etc.) for MBS data reception. The provided NR MBS configuration optionally includes neighboring cell (e.g., suitable cell) information, which the UE may directly apply in cell reselection. When transitioning to the RRC_INACTIVE state, the UE will continue to monitor MBS indications, group notifications and / or MBS associated information (e.g., in system information, paging) for MBS reception. During cell reselection, the UE may wish to select the same transport mode / bearer configuration based on the stored NR MBS configuration, because there may be a situation where a neighboring NG-RAN node shares the same PTM configuration with the serving NG-RAN node via the backhaul interface or Uu interface to achieve MBS service continuity. Upon receiving a group notification (e.g., system information, paging) from the serving cell and one or more neighboring cells, the UE shall manually select or reselect a new NG-RAN node based on the detection of a new cell identifier, MBS session identifier (e.g., TMGI) and / or MBS indication. If an MBS indication is detected indicating a deactivation of a suitable cell, the UE may manually reselect a suitable cell and attempt to camp on it. The UE sends an MBS data request (e.g., via 2 / 4 step RACH SDT, MBS tracking area update, resume RRC connection) to request activation of the MBS session.In this way, the new NG-RAN node will activate the MBS session because the 5GCN / network can identify that the UE is interested in the MBS session from the MBS context in the stored UE context. If the MBS session is active, the new NG-RAN node will receive MBS data packets from the 5GCN via shared MBS transmission. In some cases, after transmitting the MBS data request, the UE can directly apply the associated stored configuration to monitor the MBS information (e.g., NR MBS configuration, MBS paging notification) on the appropriate cell. The UE can then receive MBS data without state transition. Alternatively, a group notification with an updated NR MBS configuration (e.g., by paging) can be sent on the MBS paging occasion / RAN paging cycle. In other words, the 5GCN / network will send a group notification (e.g., by paging) to this MBS session area, which includes paging information (UE ID, UE DRX cycle, updated NR MBS configuration) of the determined UE list of the MBS session. Based on the updated NR MBS configuration, the UE can receive MBS data in the RRC_INACTIVE state accordingly. Typically, manual cell reselection is based on the UE's configuration and associated MBS QoS requirements. If no activated suitable cell / cell with acceptable MBS is detected, the UE may choose to deactivate a suitable cell.

[0129] Fig.11A scenario is shown in which an MBS-enabled UE(s) manually reselects a new MBS-acceptable cell with a deactivated shared MBS transmission mode between NG-RAN nodes according to the seventh embodiment of the present application. The UE is connected to the serving NG-RAN node to join at least one MBS session. The serving NG-RAN node as a cell that accepts MBS will decide the MBS bearer transmission mode (i.e., PTM and / or PTP) based on network conditions (e.g., QoS requirements, number of served / interested UEs, unicast / MBS traffic load, UE location, channel state information, etc.). If the UE obtains the NR MBS configuration of the serving NG-RAN node, it can receive MBS data in the RRC_CONNECTED state accordingly. In order to improve UE power efficiency, it is beneficial to enable MBS reception in the RRC_INACTIVE state. The NR MBS configuration used in the RRC_INACTIVE state can be the same as the configuration used in the RRC_CONNECTED state, or a different configuration can be used in the RRC_CONNECTED state. If the configuration used in the RRC_INACTIVE state is a separate configuration, the UE may receive dedicated signaling (e.g., RRCRelease) carrying the NR MBS configuration (e.g., including MBS session ID, G-RNTI, G-CS-RNTI, PTM / PTP configuration of MRB, scheduling information of MTCH, DRX of MBS, HARQ configuration, etc.) for MBS data reception. The provided NR MBS configuration optionally includes neighboring cell (e.g., suitable cell) information, which the UE may directly apply in cell reselection. When transitioning to the RRC_INACTIVE state, the UE will continue to monitor MBS indications, group notifications and / or MBS associated information (e.g., in system information, paging) for MBS reception. During cell reselection, the UE may wish to select the same transport mode / bearer configuration based on the stored NR MBS configuration, because there may be a situation where the neighboring NG-RAN node shares the same PTM configuration with the serving NG-RAN node via the backhaul interface or Uu interface to achieve MBS service continuity. Upon receiving a group notification (e.g., system information, paging) from the serving cell and one or more neighboring cells, the UE shall manually select or reselect a new NG-RAN node based on the detection of a new cell identifier, MBS session identifier (e.g., TMGI) and / or MBS indication. If only an MBS indication indicating a deactivated MBS-acceptable cell is detected, the UE may manually reselect an MBS-acceptable cell and attempt to camp on it. The UE sends a preconfigured MBS preamble / MBS system information (SI) request to perform a dedicated RACH / on-demand SI and establish an associated MBS PDU session to activate the MBS session.In some cases, the UE sends an RRC Connection Resume Request to resume the associated MBS PDU session, thereby activating the MBS session. In some cases, if the stored MBS configuration is not available, the UE sends an MBS Data Request (e.g., via 2 / 4 step RACH SDT, MBS Tracking Area Update, Resume RRC Connection) to request the associated MBS configuration. The 5GCN / network can identify which MBS session the UE is interested in from the MBS context in the stored UE context. In this way, the UE will transition to the RRC_CONNECTED state to connect with the new NG-RAN node. If the MBS session is active and available, the new NG-RAN node will receive MBS data packets from the 5GCN via shared MBS transport. New MBS configuration and MBS data can be received accordingly. Typically, manual cell reselection is based on the UE's configuration and associated MBS QoS requirements. If no activated cell that accepts MBS is detected, the UE may choose to deactivate a cell that accepts MBS.

[0130] Fig.12A scenario is shown in which an MBS-enabled UE(s) manually reselects a new MBS-acceptable cell with a deactivated shared MBS transmission mode between NG-RAN nodes in the RRC_INACTIVE state according to the eighth embodiment of the present application. The UE is connected to the serving NG-RAN node to join at least one MBS session. The serving NG-RAN node as the cell that accepts MBS will decide the MBS bearer transmission mode (i.e., PTM and / or PTP) based on network conditions (e.g., QoS requirements, number of served / interested UEs, unicast / MBS traffic load, UE location, channel state information, etc.). If the UE obtains the NR MBS configuration of the serving NG-RAN node, it can receive MBS data in the RRC_CONNECTED state accordingly. In order to improve UE power efficiency, it is beneficial to enable MBS reception in the RRC_INACTIVE state. The NR MBS configuration used in the RRC_INACTIVE state can be the same as the configuration used in the RRC_CONNECTED state, or a different configuration can be used in the RRC_CONNECTED state. If the configuration used in the RRC_INACTIVE state is a separate configuration, the UE may receive dedicated signaling (e.g., RRCRelease) carrying the NR MBS configuration (e.g., including MBS session ID, G-RNTI, G-CS-RNTI, PTM / PTP configuration of MRB, scheduling information of MTCH, DRX of MBS, HARQ configuration, etc.) for MBS data reception. The provided NR MBS configuration may optionally include neighboring cell (e.g., suitable cell) information, which the UE may directly apply in cell reselection. When transitioning to the RRC_INACTIVE state, the UE will continue to monitor MBS indications, group notifications, and / or MBS associated information (e.g., in system information, paging) for MBS reception. During cell reselection, the UE may wish to select the same transport mode / bearer configuration based on the stored NR MBS configuration, because there may be a situation where a neighboring NG-RAN node shares the same PTM configuration with the serving NG-RAN node via the backhaul interface or Uu interface to achieve MBS service continuity. Upon receiving a group notification (e.g., system information, paging) from the serving cell and one or more neighboring cells, the UE shall manually select or reselect a new NG-RAN node based on the detection of a new cell identifier, MBS session identifier (e.g., TMGI) and / or MBS indication. If only an MBS indication indicating a deactivated MBS-acceptable cell is detected, the UE may manually reselect an MBS-acceptable cell and attempt to camp on that cell. The UE sends an MBS data request (e.g., via 2 / 4 step RACH SDT, MBS tracking area update, resume RRC connection) to request activation of the MBS session.The 5GCN / network can identify which MBS session the UE is interested in from the MBS context in the stored UE context. In this way, if necessary, the new NG-RAN node can negotiate with the 5GCN upon UE request to activate the MBS session. If the MBS session is active, the new NG-RAN node will receive MBS data packets from the 5GCN via shared MBS transmission. Then, a group notification with a new NR MBS configuration (e.g., by paging) can be sent on the MBS paging opportunity / RAN paging cycle. In other words, the 5GCN / network will send a group notification (e.g., by paging) to this MBS session area, which includes paging information (UE ID, UE DRX cycle, new NR MBS configuration) of a determined UE list for the MBS session. The UE can receive MBS data in the RRC_INACTIVE state accordingly. Typically, when an activated cell that can accept MBS is not detected, the RRC_INACTIVE UE can select a deactivated cell that can accept MBS without a state transition.

[0131] Fig.13A scenario is shown in which an MBS-enabled UE(s) manually reselects a new MBS-acceptable cell with a separate MBS transmission mode and a deactivated shared MBS transmission mode between NG-RAN nodes according to the ninth embodiment of the present application. The UE is connected to the serving NG-RAN node to join at least one MBS session. The serving NG-RAN node as a cell that accepts MBS will decide the MBS bearer transmission mode (i.e., PTM and / or PTP) based on network conditions (e.g., QoS requirements, number of served / interested UEs, unicast / MBS traffic load, UE location, channel state information, etc.). If the UE obtains the NR MBS configuration of the serving NG-RAN node, it can receive MBS data in the RRC_CONNECTED state accordingly. In order to improve UE power efficiency, it is beneficial to enable MBS reception in the RRC_INACTIVE state. The NR MBS configuration used in the RRC_INACTIVE state can be the same as the configuration used in the RRC_CONNECTED state, or a different configuration can be used in the RRC_CONNECTED state. If the configuration used in the RRC_INACTIVE state is a separate configuration, the UE can receive dedicated signaling (e.g., RRCRelease) carrying the NR MBS configuration (e.g., including MBS session ID, G-RNTI, G-CS-RNTI, PTM / PTP configuration of MRB, scheduling information of MTCH, DRX of MBS, HARQ configuration, etc.) for MBS data reception. The provided NR MBS configuration optionally includes neighboring cell (e.g., suitable cell) information, which the UE can directly apply in cell reselection. When transitioning to the RRC_INACTIVE state, the 5GCN can identify which UE is interested in the MBS session from the MBS context in the stored UE context. The UE will continue to monitor MBS indications, group notifications and / or MBS associated information (e.g., in system information, paging) for MBS reception. During cell reselection, the UE may wish to select the same transport mode / bearer configuration based on the stored NR MBS configuration, as there may be situations where neighboring NG-RAN nodes share the same PTM configuration with the serving NG-RAN node via the backhaul interface or Uu interface for MBS service continuity. Upon receiving group notifications (e.g., system information, paging) from the serving cell and one or more neighboring cells, the UE will manually select or reselect a new NG-RAN node based on the detection of the new cell identifier, MBS session identifier (e.g., TMGI) and / or MBS indication. If no MBS indication is detected for a non-MBS acceptable cell, the UE may wish to skip camping on a candidate NG-RAN node and continue searching for a cell with an MBS acceptable as the new NG-RAN node.When a deactivated MBS-acceptable cell is detected, the UE may manually reselect to camp on the cell. The operation of reselecting a deactivated MBS-acceptable cell has been described in detail in the sixth to eighth embodiments above, and therefore will not be repeated here. Typically, the UE may give priority to selecting a suitable / MBS-acceptable cell rather than a non-MBS-acceptable cell. An MBS-acceptable cell may provide continuous MBS, which is triggered by an MBS-enabled UE.

[0132] Figure 2b The MBS-enabled UE(s) according to the tenth embodiment of the present application manually reselects a new NG-RAN node, which is a RAN function split node. The gNB-CU / gNB-DU F1AP identifier and parameters associated during NR MBS configuration / data / paging transmission can be used. MBS cell reselection is performed according to the embodiments described above, wherein the RRC message proposed in this embodiment is encapsulated in the F1AP message (e.g., UE context modification, DL / UL RRC message transmission, etc.), which will not be repeated here.

[0133] The commercial benefits of some embodiments are as follows. 1. Solve problems in the prior art. 2. Better resource utilization efficiency. 3. Low latency. 4. Service continuity. 5. Provide excellent communication performance. Some embodiments of the present application are used by 5G-NR chipset suppliers, V2X communication system development suppliers, automobile manufacturers including cars, trains, trucks, buses, bicycles, motorcycles, helmets, etc., drones (unmanned aerial vehicles), smartphone manufacturers, communication equipment for public safety purposes, AR / VR equipment manufacturers (for example, games, conferences / seminars, educational purposes). Some embodiments of the present application are a combination of "techniques / processes" that can be adopted in 3GPP specifications to develop terminal products. Some embodiments of the present application can be adopted in communications in 5G NR unlicensed frequency bands. Some embodiments of the present application propose technical solutions.

[0134] The embodiment of the present application also provides a user equipment, which includes a memory and a processor coupled to the memory, wherein the processor is configured to call and run program instructions stored in the memory to execute the above-mentioned cell reselection method for MBS service continuity. The details of the method are as mentioned above and will not be repeated here.

[0135] The embodiment of the present application also provides a network node (e.g., a base station), which includes a memory and a processor coupled to the memory, wherein the processor is configured to call and run program instructions stored in the memory to execute the above-mentioned method for providing MBS service continuity. The details of the method are described above and will not be repeated here.

[0136] The embodiment of the present application further provides a computer read-only storage medium for storing a computer program. The computer read-only storage medium enables a computer to execute the corresponding program implemented by the UE / BS in each method of the embodiment of the present application, which will not be described here for the sake of brevity.

[0137] The embodiment of the present application further provides a computer program product, including computer program instructions. The computer program product enables a computer to execute the corresponding program implemented by the UE / BS in each method of the embodiment of the present application, which will not be described in detail here for the sake of brevity.

[0138] The embodiment of the present application further provides a computer program. The computer program enables a computer to execute the corresponding program implemented by the UE / BS in each method of the embodiment of the present application, which will not be described in detail here for the sake of brevity.

[0139] Although not shown in detail, any device or apparatus forming part of the network may include at least a processor, a storage unit and a communication interface, wherein the processor unit, the storage unit and the communication interface are configured to perform the method of any aspect of the present invention. Further options and selections are described below.

[0140] The signal processing functions of the embodiments of the present invention, especially the gNB and UE, can be implemented using a computing system or architecture known to those skilled in the relevant art. Computing systems such as desktop, laptop or notebook computers, handheld computing devices (PDAs, cellular phones, palmtops, etc.), mainframes, servers, clients, or any other type of dedicated or general-purpose computing device that may be desired or appropriate for a given application or environment can be used. The computing system may include one or more processors, which may be implemented using a general or dedicated processing engine (e.g., a microprocessor, microcontroller, or other control module).

[0141] The computing system may also include a main memory, such as a random access memory (RAM) or other dynamic memory, for storing instructions and information to be executed by the processor. Such a main memory may also be used to store temporary variables and other intermediate information to be executed by the processor during the execution of the instructions. The computing system may similarly include a read-only memory (ROM) or other static storage device for storing static information and instructions for the processor.

[0142] The computing system may also include an information storage system, which may include, for example, a media drive and a removable storage interface. The media drive may include a drive or other mechanism to support fixed or removable storage media, such as a hard drive, a floppy disk drive, a tape drive, an optical disk drive, a compact disk (CD) or a digital video drive (DVD), a read or write drive (R or RW), or other removable or fixed media drive. The storage medium may include, for example, a hard disk, a floppy disk, a magnetic disk, an optical disk, a CD or DVD, or other fixed or removable media that is read or written by a media drive. The storage medium may include a computer read-only storage medium having specific computer software or data stored therein.

[0143] In alternative embodiments, the information storage system may include other similar components for allowing computer programs or other instructions or data to be loaded into the computing system. Such components may include, for example, removable storage units and interfaces, such as program cartridges and cartridge interfaces, removable memory (e.g., flash memory or other removable memory modules) and memory slots, and other removable storage units and interfaces that allow software and data to be transferred from the removable storage unit to the computing system.

[0144] The computing system may also include a communication interface. Such a communication interface may be used to allow software and data to be transferred between the computing system and external devices. Examples of communication interfaces may include a modem, a network interface (such as an Ethernet or other NIC card), a communication port (such as, for example, a Universal Serial Bus (USB) port), a PCMCIA slot and card, and the like. The software and data transferred via the communication interface are in the form of signals, which may be electrical, electromagnetic, and optical signals or other signals that can be received by the communication interface medium.

[0145] In this document, the terms "computer program product", "computer-readable medium", etc. may be generally used to refer to tangible media, such as memory, storage devices, or storage units. These and other forms of computer-readable media may store one or more instructions for use by a processor comprising a computer system to cause the processor to perform specified operations. Such instructions, generally referred to as "computer program code" (which may be grouped in the form of a computer program or grouped in other groupings), when executed enable a computing system to perform the functions of embodiments of the present invention. Note that the code may directly cause a processor to perform specified operations, be compiled to do so, and / or be combined with other software, hardware, and / or firmware elements (e.g., libraries for performing standard functions) to do so.

[0146] The non-transitory computer readable medium may include at least one of the group consisting of a hard disk, a CD-ROM, an optical storage device, a magnetic storage device, a read-only memory, a programmable read-only memory, an erasable programmable read-only memory, an electrically erasable programmable read-only memory, and a flash memory. In an embodiment where the element is implemented using software, the software may be stored in a computer readable medium and loaded into a computing system, for example, using a removable storage drive. The control module (in this example, software instructions or executable computer program code) causes the processor to perform the functions of the present invention as described herein when executed by a processor in a computer system.

[0147] In addition, the concepts of the present invention can be applied to any circuit for performing signal processing functions within a network element. It is further foreseeable that, for example, semiconductor manufacturers can utilize the concepts of the present invention when designing stand-alone devices such as microcontrollers of application specific integrated circuits (ASICs) or digital signal processors (DSPs) and / or any other subsystem elements.

[0148] It will be appreciated that, for purposes of clarity, the above description has been described with reference to a single processing logic for embodiments of the present invention. However, the concepts of the present invention may equally be implemented by a plurality of different functional units and processors to provide signal processing functionality. Therefore, references to specific functional units are only considered references to appropriate means for providing the described functionality, rather than indicating a strict logical or physical structure or organization.

[0149] Aspects of the present invention may be implemented in any suitable form, including hardware, software, firmware or any combination of these. The present invention may optionally be implemented at least in part as computer software running on one or more data processors and / or digital signal processors or configurable module components such as FPGA devices.

[0150] Therefore, the elements and components of the embodiments of the present invention can be physically, functionally and logically implemented in any appropriate manner. In fact, the function can be implemented in a single unit, in multiple units, or as a part of other functional units. Although the present invention has been described in conjunction with some embodiments, it is not intended to be limited to the specific form set forth herein. On the contrary, the scope of the present invention is limited only by the appended claims. In addition, although certain features have been described in conjunction with specific embodiments, it will be appreciated by those skilled in the art that different features of the described embodiments can be combined according to the present invention. In the claims, the term "comprising" does not exclude the presence of other elements or steps.

[0151] Furthermore, although listed individually, a plurality of means, elements or method steps may be implemented, for example, by a single unit or processor. Furthermore, although individual features may be included in different claims, these may also be advantageously combined, and the inclusion in different claims does not imply that a combination of features is not feasible and / or advantageous. Furthermore, the inclusion of a feature in one category of claims does not imply limitation to that category, but rather indicates that the feature is equally applicable to other claim categories where appropriate.

[0152] Furthermore, the order of features in the claims does not imply any specific order in which the features must be performed and in particular the order of individual steps in a method claim does not imply that the steps must be performed in this order. On the contrary, the steps may be performed in any suitable order. Furthermore, singular references do not exclude plural references. Thus, references to "a", "first", "second" etc. do not exclude plural references.

[0153] While the present application has been described in connection with what is considered to be the most practical and preferred embodiments, it is to be understood that the application is not limited to the disclosed embodiments, but is intended to cover various arrangements that may be made without departing from the scope of the broadest interpretation of the appended claims.

Claims

1. A cell reselection method for multicast and / or broadcast service MBS service continuity, performed by an energy-saving user equipment UE in a network, the method comprising: In the power saving state, based on the MBS configuration, staying on the first cell to receive MBS data; receiving signaling from at least one of the first cell and at least one neighboring cell so that the energy-saving UE prioritizes a plurality of cells for cell reselection, wherein the MBS indication included in the signaling is configured to identify whether an MBS session of an associated cell is activated; as well as A second cell is selected from the at least one neighboring cell based on the MBS indication, and camps on the second cell from the first cell for the MBS data reception.

2. The method according to claim 1, wherein if the MBS indication is set to a value, the MBS session of the associated cell is deactivated, and if the MBS indication is set to another value different from the one value, the MBS session of the associated cell is activated to perform MBS in the power saving state. 3 . The method according to claim 2 , wherein a neighboring cell having an activated MBS session is preferentially selected as the second cell. 4 . The method of claim 1 , wherein the UE selects the second cell further based on detection of at least one of a new cell identifier and an MBS Temporary Mobile Group Identity (TMGI). 5 . The method according to claim 1 , wherein the MBS indication is further configured to identify at least one of a point-to-multipoint (PTM) transmission mode and a point-to-point (PTP) transmission mode supported by the associated cell to transmit MBS data.

6. The method according to claim 5, wherein if the MBS indication is set to a first value, the PTM transmission mode is supported, if the MBS indication is set to a second value, the PTP transmission mode is supported, and if the MBS indication is set to a third value, both the PTM transmission mode and the PTP transmission mode are supported.

7. The method according to claim 5, wherein a neighboring cell that supports the same transmission mode as the transmission mode previously used by the UE is preferentially selected as the second cell.

8. The method according to claim 7, further comprising: An indication is received to indicate whether a transmission mode used by the first cell to transmit MBS data is the same as that of the at least one neighboring cell.

9. The method according to claim 1, wherein a neighboring cell having the same PTM configuration as the first cell is preferentially selected as the second cell.

10. The method of claim 9, wherein during cell reselection, a neighboring cell having an activated MBS session and having the same PTM configuration as the first cell is first selected as the second cell.

11. The method according to claim 9, further comprising: An indication is received to indicate whether the PTM configuration used by the UE to receive MBS data from the first cell is the same as that of the at least one neighboring cell. 12 . The method according to claim 1 , wherein the UE receives MBS data from the second cell without performing a state transition.

13. The method according to claim 1, wherein the MBS configuration includes neighboring cell information that can be directly used by the UE for cell reselection.

14. The method according to claim 13, wherein all suitable cells provided in the stored neighboring cell information are cells capable of providing MBS control and data channels to continue MBS data transmission via at least one of PTM and PTP transmission modes.

15. The method of claim 1, wherein when the UE camps on the second cell, the UE directly applies the stored MBS configuration for the first cell for the MBS data reception.

16. The method according to claim 1, wherein a cell that can accept MBS is selected as the second cell where the UE resides, and the cell that can accept MBS is a cell that provides MBS control and data channels to continue MBS data transmission through at least one of PTM and PTP transmission modes.

17. The method according to claim 16, further comprising: The UE sends at least one of an MBS preamble and an MBS system information SI request to request to join the ongoing MBS session and establish an associated MBS packet data unit PDU session.

18. The method according to claim 16, further comprising: The UE sends an MBS data request via a random access (RA) procedure or an MBS tracking area update to request to join the ongoing MBS session.

19. The method of claim 1, wherein if an MBS indication indicating a cell associated with a deactivated MBS session is detected, the method further comprises: The UE sends at least one of an MBS preamble and an MBS system information SI request to activate the MBS session and establish an associated MBS packet data unit PDU session.

20. The method of claim 1, wherein if an MBS indication indicating a cell associated with a deactivated MBS session is detected, the method further comprises: The UE sends an MBS data request via a random access (RA) procedure or an MBS tracking area update to request activation of the MBS session.

21. The method according to claim 1, wherein if only a non-MBS acceptable cell is detected, the UE camps on the non-MBS acceptable cell, the non-MBS acceptable cell being a cell providing MBS data in a unicast manner when the UE is in a non-power saving state.

22. The method according to claim 21, further comprising: The UE receives downlink control information DCI carrying scheduling information of the MBS data.

23. The method of claim 1, wherein during transmission of the MBS configuration, MBS data, or paging, at least one of an association identifier and a parameter of a Radio Access Network (RAN) function split node providing a cell is used.

24. A method for providing multicast and / or broadcast service MBS service continuity, the method being performed by a network node in a network, the method comprising: Signaling is sent to an energy-saving user equipment UE so that the UE prioritizes multiple cells for cell reselection, wherein the MBS indication included in the signaling is configured to identify whether the MBS session of the associated cell is activated, so that the UE decides whether to change from the serving cell to the associated cell for MBS data reception.

25. The method of claim 24, wherein if the MBS indication is set to a value, the MBS session of the associated cell is deactivated, and if the MBS indication is set to another value different from the one value, the MBS session of the associated cell is activated to enable the UE in the power saving state to perform MBS.

26. The method of claim 25, wherein if the MBS indication indicates that the associated cell has an activated MBS session, the associated cell is preferentially selected by the UE for cell reselection.

27. The method according to claim 24, wherein the MBS indication is further configured to identify at least one of a point-to-multipoint (PTM) transmission mode and a point-to-point (PTP) transmission mode supported by the associated cell to transmit MBS data.

28. The method according to claim 27, wherein if the MBS indication is set to a first value, the PTM transmission mode is supported, if the MBS indication is set to a second value, the PTP transmission mode is supported, and if the MBS indication is set to a third value, both the PTM transmission mode and the PTP transmission mode are supported.

29. The method according to claim 27, wherein if the MBS indication indicates that the transmission mode supported by the associated cell is the same as the transmission mode used by the UE, the UE preferentially selects the associated cell for cell reselection.

30. The method of claim 29, further comprising: An indication is sent to indicate that the serving cell uses the same transmission mode as the associated cell to transmit MBS data.

31. The method of claim 24, wherein if the associated cell has the same PTM configuration as the serving cell, the UE preferentially selects the associated cell for cell reselection.

32. The method of claim 24, wherein if the associated cell has the same activated MBS session and PTM configuration as the serving cell, the UE preferentially selects the associated cell for cell reselection.

33. The method of claim 31 further comprising: An indication is sent to indicate whether the PTM configuration used by the UE to receive MBS data from the serving cell is the same as that of the associated cell.

34. The method of claim 24, wherein the network node shares the same PTM configuration with other network nodes in the network.

35. The method of claim 24, further comprising: The MBS data is received from the core network through a shared MBS transmission or a separate MBS transmission.

36. The method of claim 24, further comprising: Neighboring cell information that can be directly applied by the UE for cell reselection is sent to the UE.

37. The method according to claim 36, wherein the neighboring cell information includes suitable cells, and all suitable cells are cells that can provide MBS control and data channels to continue MBS data transmission via at least one of PTM and PTP transmission modes.

38. The method of claim 24, wherein the sent signaling indicates that the MBS indication exists, which indicates that the associated cell is a cell that can accept MBS, and the cell that can accept MBS is a cell that provides MBS control and data channels to continue MBS data transmission through at least one of PTM and PTP transmission methods.

39. The method of claim 38, further comprising: At least one of an MBS preamble and an MBS system information (SI) request is received by the network node from the UE, requesting to join the ongoing MBS session and establish an associated MBS packet data unit (PDU) session.

40. The method of claim 38, further comprising: An MBS data request sent via a random access (RA) procedure or an MBS tracking area update is received by the network node, requesting to join the ongoing MBS session.

41. The method of claim 24, wherein if the MBS indication indicates the associated cell having a deactivated MBS session, the method further comprises: At least one of an MBS preamble and an MBS system information (SI) request is received by the network node from the UE, requesting to activate the MBS session and establish an associated MBS packet data unit (PDU) session.

42. The method of claim 24, wherein if the MBS indication indicates the associated cell having a deactivated MBS session, the method further comprises: An MBS data request sent via a random access (RA) procedure or an MBS tracking area update is received by the network node from the UE, requesting activation of the MBS session.

43. The method according to claim 24, wherein the sent signaling does not indicate the MBS indication, which indicates that the associated cell is a non-MBS acceptable cell, and the non-MBS acceptable cell is a cell that provides MBS data in a unicast manner when the UE is in a non-power saving state.

44. The method of claim 43, further comprising: The network node sends downlink control information DCI carrying scheduling information of the MBS data to the UE.

45. The method of claim 24, wherein during transmission of the MBS configuration, MBS data, or paging, at least one of an association identifier and a parameter of a split node is used using a Radio Access Network RAN ​​function.

46. ​​A user equipment (UE), comprising a memory and a processor coupled to the memory, wherein the processor is configured to call and run program instructions stored in the memory to perform the method according to any one of claims 1 to 23.

47. A network node, comprising a memory and a processor coupled to the memory, the processor being configured to call and run program instructions stored in the memory to perform the method according to any one of claims 24 to 45.

48. A non-transitory machine-readable storage medium having instructions stored thereon, which, when executed by a computer, cause the computer to perform the method according to any one of claims 1 to 45.

49. A chip, comprising: The processor is configured to call and run a computer program stored in the memory, so that a device equipped with the chip executes the method according to any one of claims 1 to 45.

50. A computer-readable storage medium having a computer program stored thereon, wherein the computer program causes a computer to execute the method according to any one of claims 1 to 45.

51. A computer program product comprising a computer program, wherein the computer program causes a computer to perform the method according to any one of claims 1 to 45.

52. A computer program, wherein the computer program causes a computer to perform the method according to any one of claims 1 to 45.

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