Method and apparatus for multicast and broadcast services

Abstract

Embodiments of the present application relate to a method and apparatus for multicast and broadcast services (MBS). According to embodiments of the present application, an exemplary method includes receiving conditional handover (CHO) configuration information, wherein the CHO configuration information indicates a set of execution conditions for a set of candidate cells, each execution condition being associated with a candidate cell; and performing a CHO procedure to a target cell in the set of candidate cells in response to at least one of the set of execution conditions being satisfied, wherein the target cell is determined based on the set of execution conditions and MBS information associated with CHO.

Description

Technical Field

[0001] The embodiments of this application generally relate to wireless communication technology, and more particularly to methods and apparatus for multicast and broadcast services (MBS). Background Technology

[0002] In New Radio (NR) Release 17, the MBS program focuses on small-area hybrid mode multicast (also known as Objective A in TR 23.757). Objective A concerns enabling universal MBS services on 5G systems (5GS) and identified use cases that can benefit from this feature. These use cases include, but are not limited to: public safety and mission-critical applications, vehicle-to-everything (V2X) applications, transparent Internet Protocol version 4 (IPv4) / Internet Protocol version 6 (IPv6) multicast delivery, Internet Protocol Television (IPTV), wireless software delivery, group communications, and Internet of Things (IoT) applications. In these use cases, the requirements for service continuity and reliability have changed. To support these requirements, one objective introduced in RP-201038 is to specify support for dynamic changes in broadcast / multicast service delivery between multicast (e.g., point-to-multipoint (PTM) mode) and unicast (e.g., point-to-point (PTP) mode) for service continuity for a given User Equipment (UE).

[0003] At the same time, at the RAN2#111 meeting, it was agreed that handover with variants would be supported. However, RAN2#111 only assumes that handover (with variants) is the baseline for version 17 NR multicast mobility in connected mode, and which variants are used for MBS needs to be further defined.

[0004] Therefore, given the switching that includes variations (e.g., conditional switching (CHO)), improved technical solutions for MBS should be carefully considered. Summary of the Invention

[0005] One objective of this application is to provide a method and apparatus for MBS, and more particularly a method and apparatus for MBS supporting CHO.

[0006] According to some embodiments of this application, an exemplary method may include: receiving CHO configuration information, wherein the CHO configuration information indicates a set of execution conditions for a set of candidate cells, each execution condition being associated with a candidate cell; and performing a CHO process to a target cell in the set of candidate cells in response to satisfying at least one of the set of execution conditions, wherein the target cell is determined based on the set of execution conditions and MBS information associated with the CHO.

[0007] In some embodiments of this application, the MBS information associated with the CHO is a list of cells for MBS, comprising at least one of the following: a list of cells supporting MBS; a list of cells with ongoing MBS sessions; a list of cells with MBS Service / Session Area Identifiers (SAIs); and a list of cells that also provide ongoing MBS sessions in the current cell. An exemplary method may further include receiving the MBS information associated with the CHO via a message received for MBS configuration. In another exemplary method, the set of candidate cells is determined based on the MBS information associated with the CHO, and the target cell is determined from the set of candidate cells based on the set of execution conditions.

[0008] In some other embodiments of this application, the MBS information associated with the CHO is information about at least one of the MBS session and MBS bearer associated with each candidate cell, indicating at least one of the following: whether an ongoing MBS session is admitted to a candidate cell; whether an ongoing MBS bearer is admitted to a candidate cell; whether the ongoing MBS session remains in the candidate cell; and whether the ongoing MBS bearer remains in the candidate cell. An exemplary method may further include receiving the MBS information associated with the CHO via a message received for the CHO configuration information. In another exemplary method, the set of candidate cells is determined based on the MBS information associated with the CHO, and the target cell is determined from the set of candidate cells based on the set of execution conditions.

[0009] In some other embodiments of this application, the MBS information associated with the CHO is a System Information Block (SIB) or Multicast Control Channel (MCCH) received from a different cell.

[0010] According to some embodiments of this application, an exemplary method may include: determining MBS information associated with a CHO; and transmitting CHO configuration information, wherein the CHO configuration information indicates a set of execution conditions for the set of candidate cells, each execution condition being associated with a candidate cell.

[0011] In some embodiments of this application, the MBS information associated with the CHO is a list of cells for MBS, comprising at least one of the following: a list of cells supporting MBS; a list of cells with ongoing MBS sessions; a list of cells with MBS SAI; and a list of cells that also provide ongoing MBS sessions in the current cell. An exemplary method may further include transmitting the MBS information associated with the CHO via a message for MBS configuration. Another exemplary method may include determining the set of candidate cells based on the MBS information associated with the CHO.

[0012] In some other embodiments of this application, the MBS information associated with the CHO is information about at least one of the MBS sessions and MBS bearers associated with each candidate cell, indicating at least one of the following: whether an ongoing MBS session is admitted to a candidate cell; whether an ongoing MBS bearer is admitted to a candidate cell; whether the ongoing MBS session remains in the candidate cell; and whether the ongoing MBS bearer remains in the candidate cell. An exemplary method may further include transmitting the MBS information associated with the CHO via a message for transmitting the CHO configuration information. Another exemplary method may include determining the set of candidate cells based on the MBS information associated with the CHO.

[0013] In some other embodiments of this application, an exemplary method may include receiving the MBS information associated with CHO from a base station of the set of candidate cells or from Operation, Management and Maintenance (OAM).

[0014] Additionally, embodiments of this application also provide an apparatus for performing methods according to embodiments of this application, such as the methods described above. An exemplary apparatus may include: at least one non-transitory computer-readable medium storing computer-executable instructions thereon; at least one receiving circuitry system; at least one transmitting circuitry system; and at least one processor coupled to the at least one non-transitory computer-readable medium, the at least one receiving circuitry system, and the at least one transmitting circuitry system. The computer-executable instructions cause the at least one processor to use the at least one receiving circuitry system and the at least one transmitting circuitry system to implement any method according to embodiments of this application.

[0015] The embodiments of this application can solve the technical problem of supporting CHO in MBS to reduce MBS service interruptions attributable to handover, and are beneficial to the deployment and implementation of NR. Attached Figure Description

[0016] To illustrate the advantages and features of this disclosure, the description of the disclosure is presented with reference to specific embodiments illustrated in the accompanying drawings. These drawings depict only exemplary embodiments of the disclosure and should therefore not be construed as limiting its scope.

[0017] Figure 1 This is a schematic diagram illustrating an exemplary wireless communication system according to some embodiments of this application;

[0018] Figure 2 A flowchart illustrating the exemplary legacy CHO process;

[0019] Figure 3 This is a flowchart illustrating an exemplary method for MBS according to some embodiments of this application;

[0020] Figure 4 This is a flowchart illustrating an exemplary method for MBS according to some other embodiments of this application;

[0021] Figure 5 This is a flowchart illustrating an exemplary CHO process for multicast mobility in a connected mode according to some embodiments of this application;

[0022] Figure 6 This is a flowchart illustrating an exemplary CHO process for multicast mobility in a connected mode according to some other embodiments of this application;

[0023] Figure 7 This is a flowchart illustrating an exemplary CHO process for multicast mobility in a connected mode according to some and other embodiments of this application;

[0024] Figure 8 This is a flowchart illustrating an exemplary CHO process for multicast mobility in a connected mode according to some and other embodiments of this application;

[0025] Figure 9 This is a flowchart illustrating an exemplary CHO process for multicast mobility in a connected mode according to some and other embodiments of this application; and

[0026] Figure 10 A block diagram illustrating an exemplary device according to some embodiments of this application. Detailed Implementation

[0027] The detailed description of the accompanying drawings is intended to illustrate preferred embodiments of the present application and is not intended to represent the only form in which the present application may be practiced. It should be understood that the same or equivalent functionality may be achieved through different embodiments intended to be covered within the spirit and scope of the present application.

[0028] Reference will now be made to some embodiments of this application, examples of which are illustrated in the accompanying drawings. To facilitate understanding, embodiments are provided in specific network architectures and new service scenarios, such as 3GPP 5G and 3GPP Long Term Evolution (LTE). It has been considered that all embodiments in this application are applicable to similar technical problems as network architectures and new service scenarios evolve; furthermore, the terminology used in this application may be changed without affecting the principles of this application.

[0029] Figure 1 A schematic diagram illustrating an exemplary wireless communication system 100 according to some embodiments of this application.

[0030] like Figure 1 As shown, the wireless communication system 100 includes a BS 101 and a UE 103. Although for simplicity... Figure 1 Only one BS is described herein, but it is considered that in some other embodiments of this application, the wireless communication system 100 may include more BSs. Similarly, although for simplicity, in Figure 1 Only one UE is described in this application, but in some other embodiments of this application, the wireless communication system 100 may include more UEs.

[0031] BS 101 may also be referred to as an access point, access terminal, base station, macro cell, node B, enhanced node B (eNB), gNB, home node B, relay node, or device, or described using other terms used in the field. BS 101 is typically part of a radio access network, which may include a controller communicatively coupled to BS 101.

[0032] UE 103 may include computing devices such as desktop computers, laptop computers, personal digital assistants (PDAs), tablet computers, smart TVs (e.g., TVs connected to the Internet), set-top boxes, game consoles, security systems (including security cameras), in-vehicle computers, network devices (e.g., routers, switches, and modems), etc. According to embodiments of this application, UE 103 may include portable wireless communication devices, smartphones, cellular phones, flip phones, devices with subscriber identity modules, personal computers, selective call receivers, or any other devices capable of transmitting and receiving communication signals on a wireless network. In some embodiments, UE 103 may include wearable devices such as smartwatches, fitness bands, optical head-mounted displays, etc. Furthermore, UE 103 may be referred to as a subscriber unit, mobile station, mobile base station, user, terminal, mobile terminal, wireless terminal, fixed terminal, subscriber station, user terminal, or device, or described using other terms used in the art.

[0033] The wireless communication system 100 is compatible with any type of network capable of transmitting and receiving wireless communication signals. For example, the wireless communication system 100 is compatible with wireless communication networks, cellular telephone networks, time division multiple access (TDMA) based networks, code division multiple access (CDMA) based networks, orthogonal frequency division multiple access (OFDMA) based networks, LTE networks, 3GPP based networks, 3GPP 5G networks, satellite communication networks, high-altitude platform networks, and / or other communication networks.

[0034] In NR Release 17, MBS was introduced to focus on small area hybrid mode multicast. According to RAN2#111, in connected mode, NR Release 17 multicast mobility will support handover variants. CHO is a handover variant introduced in Release 16. Unlike traditional handover, CHO is defined as a handover performed by the UE when one or more handover execution conditions are met.

[0035] For example, Figure 2 A flowchart illustrating a model legacy CHO process. For example... Figure 2 The diagram depicts a basic CHO scenario where the Access and Mobility Management Function (AMF) and User Plane Function (UPF) remain unchanged.

[0036] refer to Figure 2 In step 200, the AMF may provide the UE context of the UE (e.g., UE 103) to the BS (e.g., BS 101). The BS receiving the UE context is referred to as the UE's source BS. The UE context may contain information about the UE's roaming and access restrictions.

[0037] In step 201, the source BS may transmit measurement configuration information to the UE. The UE will perform measurements based on the measurement configuration information, such as a reference signal received power (RSRP) measurement, and report the measurement results to the source BS.

[0038] In step 202, the source BS may decide to use CHO for the UE based on the measurement results reported by the UE.

[0039] In step 203, the source BS may send a CHO request message to one or more candidate BSs. For example, one or more candidate BSs may include the target BS and other potential target BSs.

[0040] In step 204, the target BS and other potential target BSs may perform admission control after receiving a CHO request message from the source BS to determine whether to allow the UE's CHO.

[0041] In step 205, based on the admission control results, at least one of the target BS and other potential target BSs may transmit a CHO response message to the source BS. The CHO response message may contain the CHO configuration of one or more candidate cells.

[0042] In step 206, the source BS may transmit a Radio Resource Control (RRC) reconfiguration message to the UE. The RRC reconfiguration message may contain CHO configuration information indicating a set of cells and a set of execution conditions, with each cell associated with a CHO configuration and execution conditions. The set of cells may include one or more candidate cells provided by at least one of the target BS and other potential target BSs.

[0043] The CHO configuration associated with a cell may contain parameters for the UE to perform a handover to the cell. For example, the CHO configuration associated with a cell may contain parameters for the UE to access the cell and / or perform data transmission with the cell.

[0044] The execution conditions may include one or two trigger conditions. For example, if the execution conditions include one trigger condition, the trigger condition may be an A3 event or an A5 event as specified in 3GPP standard document TS38.331. If the execution conditions include two trigger conditions, the two trigger conditions may be an A3 event and an A5 event as specified in 3GPP standard document TS38.331. Additionally, the execution conditions of a single cell may be evaluated using only a single Reference Signal (RS) type, and up to two different execution quantities may be configured simultaneously to evaluate the execution conditions of a single cell. For example, the two different execution quantities may be RSRP and Reference Signal Received Quality (RSRQ), or RSRP and Signal-to-Interference-plus-Noise Ratio (SINR) or similar. In some embodiments of this application, more than one execution condition may be satisfied, i.e., more than one cell is suitable for UE handover. In this case, the UE may select the cell for performing a CHO based on the execution quantity.

[0045] After receiving the RRC reconfiguration message, in step 207, the UE may send an RRC reconfiguration complete message to the source BS.

[0046] In step 208, the UE may maintain its connection with the source BS and begin evaluating a set of execution conditions for a group of cells. Before any execution conditions are met, the UE may execute an HO procedure upon receiving a handover (HO) command without CHO configuration, regardless of any previously received CHO configuration information. Otherwise, if at least one execution condition for at least one candidate cell is met, in step 209, the UE may disconnect from the source BS and execute (or apply) a CHO procedure to a cell selected from at least one cell. The selected cell may be referred to as the target cell.

[0047] The CHO procedure for the selected cell may include applying the corresponding CHO configuration to the selected cell. When executing the CHO procedure, for example, from the time the UE begins synchronization with the selected cell, the UE no longer monitors the source BS. The UE can complete the CHO procedure by sending an RRC reconfiguration complete message to the target cell.

[0048] In step 210, the UE, source BS, target BS, and core network (e.g., AMF and / or UPF) can perform data forwarding and path switching.

[0049] Clearly, the current execution conditions of a CHO do not include any conditions associated with MBS. For a UE currently receiving MBS service (or MBS bearer), when it decides to execute the CHO procedure, there may not be any supported or transmitted MBS service (or MBS bearer) in the target cell at all. In some scenarios, there may be some supported or transmitted MBS sessions (or MBS bearers) in the target cell, but all or part of these MBS sessions (or MBS bearers) are not the MBS sessions (or MBS bearers) that were in progress on the UE before the CHO. Therefore, when the UE performs a handover to the target cell, MBS reception will be interrupted, which fails to meet the basic broadcast / multicast functional requirements of the UE in the RRC_CONNECTED state, i.e., basic mobility with service continuity. In some other scenarios, the UE may not be receiving MBS service but is interested in MBS service and expects to hand over to the target cell providing MBS.

[0050] To address the aforementioned technical problems, embodiments of this application propose an improved technical solution for MBS. For those skilled in the art, handover can also mean switching from one frequency to another. Although the following embodiments only describe handover between different cells, the term "cell" can be replaced with "frequency." Therefore, in defining the reasonable scope of protection of this application, the term "cell" in this application should encompass both existing cells and existing frequencies.

[0051] Figure 3 This is a flowchart illustrating an exemplary method for MBS according to some embodiments of this application, the method being performed on a remote side (e.g., by UE 103 or the like).

[0052] like Figure 3As shown, in step 301, CHO configuration information can be received on a remote side (e.g., by UE 103). According to some embodiments of this application, CHO configuration information is received via an RRC reconfiguration message from a source BS, for example, serving UE 103. The CHO configuration information indicates a set of execution conditions for a set of candidate cells, each execution condition associated with a candidate cell. The set of candidate cells includes one or more potential target cells for CHO.

[0053] Upon receiving CHO configuration information, the UE can maintain its connection with the source BS and begin evaluating a set of execution conditions for a set of candidate cells. Before any execution conditions are met, the UE can execute the HO procedure upon receiving a HO command without CHO configuration, regardless of any previously received CHO configuration information. Otherwise, in step 303, the UE can execute a CHO procedure for a target cell in the set of candidate cells in response to the satisfaction of at least one of the set of execution conditions. The target cell is determined (or selected) based on the set of execution conditions and the MBS information associated with the CHO.

[0054] In some embodiments of this application, the MBS information associated with the CHO is a list of cells for MBS, comprising at least one of the following: a list of cells supporting MBS; a list of cells with ongoing MBS sessions; a list of cells with MBS SAI; and a list of cells that also provide ongoing MBS sessions in the current cell. An exemplary method may further include receiving the MBS information associated with the CHO from a source BS via a message for MBS configuration, for example, RRC signaling indicating a dedicated MBS configuration for the UE. In some other embodiments of this application, the list of cells for MBS may be received from the source BS via another message. When determining a target cell from a set of candidate cells, the UE will also consider the MBS information associated with the CHO, in addition to a set of execution conditions, for example, prioritizing the cells in the cell list for MBS. In another exemplary method, firstly, for example in the source BS, a set of candidate cells indicated in the CHO configuration information is determined based on the MBS information associated with the CHO. When determining a target cell from a set of candidate cells, the UE only needs to treat the set of execution conditions as prior art.

[0055] In some other embodiments of this application, the MBS information associated with the CHO is information about at least one of the MBS sessions and MBS bearers associated with each candidate cell, indicating at least one of the following: whether an ongoing MBS session is admitted to a candidate cell; whether an ongoing MBS bearer is admitted to a candidate cell; whether the ongoing MBS session remains in the candidate cell; and whether the ongoing MBS bearer remains in the candidate cell. An exemplary method may further include receiving the MBS information associated with the CHO from a source BS via a message for CHO configuration information, such as an RRCReconfiguration message. In some other embodiments of this application, the list of MBS cells may be received from the source BS via another message. When a target cell is determined from a set of candidate cells, in addition to a set of execution conditions, the UE will also consider the MBS information associated with the CHO, for example, prioritizing cells for admitting ongoing MBS sessions or admitting ongoing MBS bearers. In another exemplary method, firstly, for example in the source BS, a set of candidate cells indicated in the CHO configuration information is determined based on the MBS information associated with the CHO. When determining the target cell from a set of candidate cells, the UE only needs to treat a set of execution conditions as legacy technology.

[0056] In some other embodiments of this application, the MBS information associated with the CHO is SIB or MCCH received from different cells. The received SIB or MCCH indicates that the associated cell is transmitting MBS service. The cell receiving the SIB or MCCH may be the same as or different from the candidate cells indicated in the CHO configuration information. When determining the target cell from a set of candidate cells, the UE will consider the MBS information associated with the CHO, in addition to a set of execution conditions, for example, prioritizing the cells from which it receives the SIB or MCCH.

[0057] A similar process can be performed on the network side. For example, Figure 4 This is a flowchart illustrating an exemplary method for an MBS according to some other embodiments of this application, which can be performed on the network side, for example by a source BS. Considering the consistency between the network side and the UE side, the exemplary process will be briefly described on the network side.

[0058] like Figure 4As shown, in step 401, MBS information associated with the CHO is determined in the source BS. In some embodiments of this application, the MBS information associated with the CHO is a list of cells for MBS, which includes at least one of the following: a list of cells supporting MBS; a list of cells with ongoing MBS sessions; a list of cells with MBS SAI; and a list of cells that also provide ongoing MBS sessions provided in the current cell. In some other embodiments of this application, the MBS information associated with the CHO is information about at least one of the MBS sessions and MBS bearers associated with each candidate cell, indicating at least one of the following: whether the ongoing MBS session is admitted to the candidate cell; whether the ongoing MBS bearer is admitted to the candidate cell; whether the ongoing MBS session remains in the candidate cell; and whether the ongoing MBS bearer remains in the candidate cell.

[0059] According to some embodiments of this application, MBS information associated with a CHO can be received from a BS of a set of candidate cells or OAM. For example, the source BS can receive MBS information from a neighboring BS providing at least one cell via an Xn message, indicating at least one of the following: for example, whether the cell supports MBS, whether the cell has an ongoing MBS session, whether the cell has MBSSAI; and whether the cell also provides an ongoing MBS session provided in the current cell. In another embodiment of this application, the source BS can receive MBS service (and / or bearer) configuration information from a neighboring BS providing at least one cell via an Xn message, indicating at least one of the following: for example, whether an ongoing MBS session is admitted to the cell; whether an ongoing MBS bearer is admitted to the cell; whether an ongoing MBS session remains in the cell; and whether an ongoing MBS bearer remains in the cell. Cells can be selected as candidate cells for a CHO. Based on the received MBS service (and / or bearer) configuration information associated with each cell, the source BS can determine the MBS information associated with the CHO.

[0060] In step 403, CHO configuration information may be transmitted to the UE. The CHO configuration information indicates a set of execution conditions for a group of candidate cells, each execution condition being associated with a candidate cell. The group of candidate cells contains one or more potential target cells for CHO.

[0061] In some embodiments of this application, the source BS may also transmit MBS information associated with the CHO to the UE, enabling the UE to use the MBS information associated with the CHO to determine the target cell. For example, the source BS may transmit a list of cells for MBS to the UE via a message for MBS configuration. In another instance, the source BS may transmit information to the UE via a message for CHO configuration information regarding at least one of the MBS session and MBS bearer associated with each candidate cell.

[0062] In some other embodiments of this application, the source BS may use MBS information associated with the CHO to select (determine) a set of candidate cells for the UE. The MBS information may not be transmitted to the UE to save overhead. When determining the target cell from a set of candidate cells, the UE only needs to treat a set of execution conditions as legacy technology.

[0063] Based on the above basic solution, further details will be described in various embodiments below. In addition to the embodiments below, those skilled in the art should understand that various embodiments of this application can be made for MBS based on the existing CHO process and the basic solution of this application, and under the teachings and suggestions of this application. Furthermore, although the following embodiments are described sequentially, this does not mean that these steps must be performed in the order described herein.

[0064] Figure 5 This is a flowchart illustrating an exemplary CHO process for multicast mobility in a connected mode according to some embodiments of this application. Although the method is described at the system level via a UE on the remote side (or UE side) and multiple BSs on the network side (or BS side), those skilled in the art will understand that the method implemented on the remote side and the method implemented on the network side can be implemented separately and combined by other devices with similar functionality.

[0065] refer to Figure 5 Assume the source BS is the BS providing services to the UE. In step 501, the source BS may receive MBS information from one or more neighboring BSs providing one or more neighboring cells. A set of candidate cells for CHO, including the target cell (which will be determined during the CHO process) and other potential target cells, will be determined or selected from the one or more neighboring cells. For simplicity, in Figure 5This document only shows the target BS of the target cell and one potential target BS of at least one potential target cell. Those skilled in the art will understand that there may be more potential target BSs or no other potential target BSs. In some embodiments of this application, the source BS may receive MBS information from a neighboring BS associated with a neighboring cell via an Xn message, indicating at least one of the following: for example, whether the neighboring cell supports MBS, whether the neighboring cell has an ongoing MBS session, whether the neighboring cell has an MBS SAI; and whether the neighboring cell also provides an ongoing MBS session available in the current cell.

[0066] In step 503, based on the received MBS information, the source BS can determine the MBS information associated with the CHO. In some embodiments of this application, the source BS can obtain (or receive) the MBS information of each neighboring cell from the OAM. In some embodiments of this application, the received or obtained MBS information can be directly used as the MBS information associated with the CHO. In some other embodiments of this application, the source BS can derive the MBS information associated with the CHO from the received or obtained MBS information. The exemplary MBS information associated with the CHO is a list of cells for MBS, which includes at least one of the following: a list of cells supporting MBS; a list of cells with ongoing MBS sessions; a list of cells with MBS SAI; and a list of cells that also provide ongoing MBS sessions provided in the current cell.

[0067] In step 505, the source BS may, for example, transmit a list of cells for MBS to the UE via a message for MBS configuration. In some embodiments of this application, the list of cells for MBS may even be included in the MBS configuration. In some other embodiments of this application, the source BS may determine the list of cells for MBS and transmit it to the UE after making a CHO decision.

[0068] In step 507, the source BS may decide to use CHO for the UE, that is, make a CHO decision based on the measurement results reported by the UE.

[0069] Therefore, in step 509, the source BS may send CHO request messages, such as handover request messages, to one or more adjacent BSs.

[0070] In step 511, one or more neighboring BSs may perform admission control after receiving a CHO request message from the source BS to determine whether to allow the UE's CHO.

[0071] In step 513, based on the admission control result, at least one of one or more neighboring BSs may transmit a CHO response message to the source BS, such as a handover request confirmation message or a handover request failure message. Each CHO response message for admission CHO may contain the CHO configuration of the corresponding cell. The source BS may determine a set of candidate cells for CHO for the UE based on the received CHO response messages, for example, including only the cells associated with the handover request confirmation message.

[0072] In step 515, the source BS may transmit CHO configuration information to the UE. In some embodiments of this application, the CHO configuration information may be transmitted via an RRCReconfiguration message. The CHO configuration information indicates a set of execution conditions for a group of candidate cells, each execution condition being associated with a candidate cell. A set of execution conditions may include one or two trigger conditions. For example, similar to the prior art, where the execution conditions include a trigger condition, the trigger condition may be an A3 event or an A5 event as specified in 3GPP standard document TS38.331.

[0073] According to some embodiments of this application, in step 517, in response to receiving CHO configuration information, the UE may transmit a feedback message to the source BS, such as an RRCReconfigurationComplete message.

[0074] In step 519, the UE may maintain its connection with the source BS and begin evaluating a set of execution conditions for a group of candidate cells. Before any execution conditions are met, the UE may execute the HO procedure upon receiving an HO command without CHO configuration, regardless of any previously received CHO configuration information. Otherwise, if at least one execution condition for at least one candidate cell is met, in step 521, the UE may disconnect from the source BS and execute a CHO procedure for a candidate cell determined (or selected) from at least one candidate cell. The determined candidate cell is the target cell.

[0075] According to some embodiments of this application, during the target cell determination period, when more than one execution condition is met, the UE will prioritize candidate cells in the cell list for MBS. For example, both cell 1 and cell 2 (not shown) meet their respective execution conditions indicated in the CHO configuration information, wherein, according to the cell list for MBS, cell 1 supports MBS or supports an ongoing MBS session, while cell 2 does not. Therefore, the UE will select cell 1 as the target cell. In some other embodiments of this application, when more than one candidate cell in the cell list for MBS meets its respective execution condition, the UE may prioritize candidate cells that support an ongoing MBS session. For example, both cell 1 and cell 2 may support MBS, but only cell 1 supports an ongoing MBS session. The UE will select cell 1 as the target cell. In some other embodiments of this application, when more than one candidate cell in the cell list for MBS meets its respective execution condition, the UE may randomly select the target cell. Those skilled in the art will understand that various selection mechanisms exist when more than one candidate cell in the cell list for MBS meets its corresponding execution conditions. The illustrated embodiments should not be used to limit the scope of this application.

[0076] Figure 6 This is a flowchart illustrating an exemplary CHO process for multicast mobility in a connected mode according to some other embodiments of this application. Although the method is described at the system level via a UE on the remote side (or UE side) and multiple BSs on the network side (or BS side), those skilled in the art will understand that the method implemented on the remote side and the method implemented on the network side can be implemented separately and combined by other devices with similar functionality.

[0077] refer to Figure 6 Assume the source BS is the BS that provides services to the UE. Based on the measurement results reported by the UE (e.g., RSRP report), the source BS can decide to use CHO for the UE, that is, make the CHO decision in step 601.

[0078] Therefore, in step 603, the source BS may transmit a CHO request message, such as a handover request message, to one or more neighboring BSs providing one or more neighboring cells. A set of candidate cells for CHO, including the target cell (which will be determined during the CHO process) and other potential target cells, will be determined or selected from the one or more neighboring cells. For simplicity, in Figure 6 This document only shows the target BS of the target cell and one potential target BS of at least one potential target cell. Those skilled in the art should understand that there may be more potential target BSs or no other potential target BSs.

[0079] According to some embodiments of this application, a source BS may transmit MBS context to one or more neighboring BSs to obtain information about at least one of the MBS sessions and MBS bearers associated with each corresponding cell. The MBS context may be transmitted together with a CHO request message or via another Xn message.

[0080] In step 605, one or more neighboring BSs may perform admission control after receiving a CHO request message from the source BS to determine whether to allow the UE's CHO.

[0081] In step 607, based on the admission control result, at least one of one or more neighboring BSs may send a CHO response message to the source BS, such as a handover request confirmation message or a handover request failure confirmation message. Each CHO response message of the admission CHO may contain the CHO configuration of the corresponding cell.

[0082] In step 609, the source BS may determine a set of candidate cells for the UE to use for CHO based on the received CHO response message, for example, including only cells associated with the handover request confirmation message.

[0083] When the source BS also transmits the MBS context along with the CHO request message, the CHO response message for admitting the CHO may also include information about at least one of the MBS session and MBS bearer associated with the corresponding cell. In some other embodiments of this application, information about at least one of the MBS session and MBS bearer associated with the corresponding cell may also be transmitted to the source BS via another Xn message. Based on the received information, the source BS may also determine information about at least one of the MBS session and MBS bearer associated with each candidate cell, namely, the MBS information associated with the CHO, which may indicate at least one of the following: whether the ongoing MBS session has been admitted to the candidate cell; whether the ongoing MBS bearer has been admitted to the candidate cell; whether the ongoing MBS session remains in the candidate cell; and whether the ongoing MBS bearer remains in the candidate cell.

[0084] In some embodiments of this application, the source BS can obtain information from the network's OAM regarding at least one of the MBS sessions and MBS bearers associated with each candidate cell. In this case, it is not necessary to transmit MBS context to one or more neighboring BSs.

[0085] In step 611, the source BS may transmit CHO configuration information to the UE. In some embodiments of this application, the CHO configuration information may be transmitted via an RRCReconfiguration message. The CHO configuration information indicates a set of execution conditions for a group of candidate cells, each execution condition being associated with a candidate cell. A set of execution conditions may include one or two trigger conditions. For example, similar to the prior art, where the execution conditions include a trigger condition, the trigger condition may be an A3 event or an A5 event as specified in 3GPP standard document TS38.331.

[0086] According to some embodiments of this application, the source BS may also transmit MBS information associated with the CHO via messages used for CHO configuration information. In some embodiments of this application, the MBS information associated with the CHO may even be included in the CHO configuration information. In some other embodiments of this application, the MBS information associated with the CHO may be transmitted to the UE via another means, for example, via another RRC signaling or downlink control information (DCI) or MAC control element (MAC CE).

[0087] According to some embodiments of this application, in step 613, in response to receiving CHO configuration information, the UE may transmit a feedback message to the source BS, such as an RRCReconfigurationComplete message.

[0088] In step 615, the UE may maintain its connection with the source BS and begin evaluating a set of execution conditions for a group of candidate cells. Before any execution conditions are met, the UE may execute the HO procedure upon receiving an HO command without CHO configuration, regardless of any previously received CHO configuration information. Otherwise, if at least one execution condition for at least one candidate cell is met, in step 617, the UE may disconnect from the source BS and execute a CHO procedure for a candidate cell determined (or selected) from at least one candidate cell. The determined candidate cell is the target cell.

[0089] According to some embodiments of this application, during target cell determination, when more than one execution condition is met, the UE will prioritize candidate cells for admission to an ongoing MBS session or MBS bearer. For example, both cell 1 and cell 2 (not shown) meet their respective execution conditions indicated in the CHO configuration information, wherein cell 1 admits the ongoing MBS session or MBS bearer, while cell 2 does not. Therefore, the UE will select cell 1 as the target cell. In some other embodiments of this application, when more than one candidate cell meets its respective execution conditions and admits the ongoing MBS session or MBS bearer, the UE may randomly select the target cell. Those skilled in the art will understand that various selection mechanisms exist when more than one candidate cell meets its respective execution conditions and admits (or maintains) the ongoing MBS session or MBS bearer, etc. The described embodiments should not be used to limit the scope of this application.

[0090] Figure 7 This is a flowchart illustrating an exemplary CHO process for multicast mobility in a connected mode according to some and other embodiments of this application. Although the method is described at the system level via a UE on the remote side (or UE side) and multiple BSs on the network side (or BS side), those skilled in the art will understand that the method implemented on the remote side and the method implemented on the network side can be implemented separately and combined by other devices with similar functionality.

[0091] refer to Figure 7 Assume the source BS is the BS that provides services to the UE. Based on the measurement results reported by the UE (e.g., RSRP report), the source BS can decide to use CHO for the UE, that is, make the CHO decision in step 701.

[0092] Therefore, in step 703, the source BS may transmit a CHO request message, such as a handover request message, to one or more neighboring BSs providing one or more neighboring cells. A set of candidate cells for CHO, including the target cell (which will be determined during the CHO process) and other potential target cells, will be determined or selected from the one or more neighboring cells. For simplicity, in Figure 7 This document only shows the target BS of the target cell and one potential target BS of at least one potential target cell. Those skilled in the art should understand that there may be more potential target BSs or no other potential target BSs.

[0093] In step 705, one or more neighboring BSs may perform admission control after receiving a CHO request message from the source BS to determine whether to allow the UE's CHO.

[0094] In step 707, based on the admission control result, at least one of one or more neighboring BSs may send a CHO response message to the source BS, such as a handover request confirmation message or a handover request failure confirmation message. Each CHO response message of the admission CHO may contain the CHO configuration of the corresponding cell.

[0095] In step 709, the source BS may determine a set of candidate cells for the UE to use for CHO based on the received CHO response message, for example, including only cells associated with the handover request confirmation message.

[0096] In step 711, the source BS may transmit CHO configuration information to the UE. In some embodiments of this application, the CHO configuration information may be transmitted via an RRCReconfiguration message. The CHO configuration information indicates a set of execution conditions for a group of candidate cells, each execution condition being associated with a candidate cell. A set of execution conditions may include one or two trigger conditions. For example, similar to the prior art, where the execution conditions include a trigger condition, the trigger condition may be an A3 event or an A5 event as specified in 3GPP standard document TS38.331.

[0097] According to some embodiments of this application, in step 713, in response to receiving CHO configuration information, the UE may transmit a feedback message to the source BS, such as an RRCReconfigurationComplete message.

[0098] Additionally, although the service is provided by the source BS, in step 714, the UE can also obtain MBS information from neighboring cells, which may be the same as or different from the candidate cell. The MBS information received from the neighboring cells may be an SIB or MCCH associated with the corresponding cell, which can provide the common MBS configuration of the corresponding neighboring cells.

[0099] In step 715, the UE may maintain its connection with the source BS and begin evaluating a set of execution conditions for a group of candidate cells. Before any execution conditions are met, the UE may execute the HO procedure upon receiving an HO command without CHO configuration, regardless of any previously received CHO configuration information. Otherwise, if at least one execution condition for at least one candidate cell is met, in step 717, the UE may disconnect from the source BS and execute a CHO procedure for a candidate cell determined (or selected) from at least one candidate cell. The determined candidate cell is the target cell.

[0100] According to some embodiments of this application, during the target cell determination period, the UE will also consider MBS information received from neighboring cells. When more than one execution condition is met, the UE will prioritize candidate cells from which it also receives MBS information. For example, both cell 1 and cell 2 (not shown) meet their respective execution conditions indicated in the CHO configuration information, and the UE also receives SIB or MCCH from cell 1 but not from cell 2. Therefore, the UE will select cell 1 as the target cell. In some other embodiments of this application, when more than one candidate cell meets its respective execution condition and its MBS information is received, the UE may randomly select the target cell. Those skilled in the art will understand that various selection mechanisms exist when more than one candidate cell meets its respective execution condition and its MBS information is received. The illustrated embodiments should not be used to limit the scope of this application.

[0101] exist Figures 5 to 7 In the embodiments described above, during target cell determination, the UE also considers MBS information received from neighboring cells, thus increasing the likelihood of MBS service and reducing MBS service interruptions. In some other embodiments, when determining candidate cells for CHO indicated to the UE by the source BS, MBS information associated with the CHO has already been considered. The UE may select the target cell solely based on execution conditions, i.e., in a manner similar to the legacy technology.

[0102] Figure 8 This is a flowchart illustrating an exemplary CHO process for multicast mobility in a connected mode according to some and other embodiments of this application. Although the method is described at the system level via a UE on the remote side (or UE side) and multiple BSs on the network side (or BS side), those skilled in the art will understand that the method implemented on the remote side and the method implemented on the network side can be implemented separately and combined by other devices with similar functionality.

[0103] refer to Figure 8 Assume the source BS is the BS providing services to the UE. In step 801, the source BS may receive MBS information from one or more neighboring BSs providing one or more neighboring cells. A set of CHO candidate cells, including the target cell (which will be determined during the CHO process) and other potential target cells, will be determined or selected from the one or more neighboring cells. For simplicity, in Figure 8This document only shows the target BS of the target cell and one potential target BS of at least one potential target cell. Those skilled in the art will understand that there may be more potential target BSs or no other potential target BSs. In some embodiments of this application, the source BS may receive MBS information from a neighboring BS associated with a neighboring cell via an Xn message, indicating at least one of the following: for example, whether the neighboring cell supports MBS, whether the neighboring cell has an ongoing MBS session, whether the neighboring cell has an MBS SAI; and whether the neighboring cell also provides an ongoing MBS session available in the current cell.

[0104] In step 803, based on the received MBS information from each neighboring BS, the source BS can determine the MBS information associated with the CHO. In some embodiments of this application, the source BS can obtain (or receive) the MBS information of each neighboring cell from the OAM. In some embodiments of this application, the received or obtained MBS information can be directly used as the MBS information associated with the CHO. In some other embodiments of this application, the source BS can derive the MBS information associated with the CHO from the received or obtained MBS information. The exemplary MBS information associated with the CHO is a list of cells for MBS, which includes at least one of the following: a list of cells supporting MBS; a list of cells with ongoing MBS sessions; a list of cells with MBS SAI; and a list of cells that also provide ongoing MBS sessions provided in the current cell.

[0105] In step 805, the source BS may decide to use CHO for the UE, that is, make a CHO decision based on the measurement results reported by the UE.

[0106] Therefore, in step 807, the source BS may send CHO request messages, such as handover request messages, to one or more neighboring BSs. In some other embodiments of this application, the source BS may send CHO request messages only to neighboring BSs of cells in the MBS's cell list.

[0107] In step 809, one or more neighboring BSs may perform admission control after receiving a CHO request message from the source BS to determine whether to allow the UE's CHO.

[0108] In step 811, based on the admission control result, at least one of one or more neighboring BSs may send a CHO response message to the source BS, such as a handover request confirmation message or a handover request failure confirmation message. Each CHO response message of the admission CHO may contain the CHO configuration of the corresponding cell.

[0109] In step 813, the source BS can determine a set of candidate cells for the CHO for the UE based on the received CHO response message and the MBS information associated with the CHO. For example, candidate cells are cells that transmit handover request confirmation messages and are included in the cell list of the MBS. If the source BS only transmits CHO request messages to neighboring BSs of cells in the cell list used for the MBS, in step 813, the source BS only needs to consider whether it has received a handover request confirmation message.

[0110] In step 815, the source BS may transmit CHO configuration information to the UE. In some embodiments of this application, the CHO configuration information may be transmitted via an RRCReconfiguration message. The CHO configuration information indicates a set of execution conditions for a group of candidate cells, each execution condition being associated with a candidate cell. A set of execution conditions may include one or two trigger conditions. For example, similar to the prior art, where the execution conditions include a trigger condition, the trigger condition may be an A3 event or an A5 event as specified in 3GPP standard document TS38.331.

[0111] According to some embodiments of this application, in response to receiving CHO configuration information, in step 817, the UE may transmit a feedback message to the source BS, such as an RRCReconfigurationComplete message.

[0112] In step 819, the UE may maintain its connection with the source BS and begin evaluating a set of execution conditions for a group of candidate cells. Before any execution conditions are met, the UE may execute the HO procedure upon receiving an HO command without CHO configuration, regardless of any previously received CHO configuration information. Otherwise, if at least one execution condition for at least one candidate cell is met, in step 821, the UE may detach from the source BS and execute a CHO procedure for a candidate cell determined (or selected) from at least one candidate cell. The determined candidate cell is the target cell. Since the candidate cell is selected based on MBS information associated with the CHO, the UE can only select the target cell from the candidate cells based on execution conditions in a manner similar to legacy technology, which also increases the likelihood of MBS service and reduces MBS interruptions for the UE.

[0113] Figure 9 This is a flowchart illustrating an exemplary method for an MBS according to some other embodiments of this application. Although the method is described at the system level via a UE on the remote side (or UE side) and multiple BSs on the network side (or BS side), those skilled in the art will understand that the method implemented on the remote side and the method implemented on the network side can be implemented separately and combined by other devices with similar functions.

[0114] refer to Figure 9 Assume the source BS is the BS that provides services to the UE. Based on the measurement results reported by the UE (e.g., RSRP report), the source BS can decide to use CHO for the UE, that is, make the CHO decision in step 901.

[0115] Therefore, in step 903, the source BS may transmit a CHO request message, such as a handover request message, to one or more neighboring BSs providing one or more neighboring cells. A set of candidate cells for CHO, including the target cell (which will be determined during the CHO process) and other potential target cells, will be determined or selected from the one or more neighboring cells. For simplicity, in Figure 9 This document only shows the target BS of the target cell and one potential target BS of at least one potential target cell. Those skilled in the art should understand that there may be more potential target BSs or no other potential target BSs.

[0116] According to some embodiments of this application, a source BS may transmit MBS context to one or more neighboring BSs to obtain information about at least one of the MBS sessions and MBS bearers associated with each corresponding cell. The MBS context may be transmitted together with a CHO request message or via another Xn message.

[0117] In step 905, one or more neighboring BSs may perform admission control after receiving a CHO request message from the source BS to determine whether to allow the UE's CHO.

[0118] In step 907, based on the admission control result, at least one of one or more neighboring BSs may send a CHO response message to the source BS, such as a handover request confirmation message or a handover request failure confirmation message. Each CHO response message of the admission CHO may contain the CHO configuration of the corresponding cell.

[0119] When the source BS also transmits the MBS context along with the CHO request message, the CHO response message for admitting the CHO may also include information about at least one of the MBS session and MBS bearer associated with the corresponding cell. In some other embodiments of this application, information about at least one of the MBS session and MBS bearer associated with the corresponding cell may also be transmitted to the source BS via another Xn message. Based on the received information, the source BS may also determine information about at least one of the MBS session and MBS bearer associated with each candidate cell, i.e., MBS information associated with the CHO. The MBS information associated with the CHO may indicate at least one of the following: whether the ongoing MBS session has been admitted to the candidate cell; whether the ongoing MBS bearer has been admitted to the candidate cell; whether the ongoing MBS session remains in the candidate cell; and whether the ongoing MBS bearer remains in the candidate cell.

[0120] In some embodiments of this application, the source BS can obtain information from the network's OAM regarding at least one of the MBS sessions and MBS bearers associated with each candidate cell. In this case, it is not necessary to transmit MBS context to one or more neighboring BSs.

[0121] In step 909, the source BS may determine a set of candidate cells for the UE to use for the CHO based on the received CHO response message and the MBS information associated with the CHO. For example, the candidate cells are cells that transmit handover request confirmation messages and admit ongoing MBS sessions or MBS bearers.

[0122] In step 911, the source BS may transmit CHO configuration information to the UE. In some embodiments of this application, the CHO configuration information may be transmitted via an RRCReconfiguration message. The CHO configuration information indicates a set of execution conditions for a group of candidate cells, each execution condition being associated with a candidate cell. A set of execution conditions may include one or two trigger conditions. For example, similar to the prior art, where the execution conditions include a trigger condition, the trigger condition may be an A3 event or an A5 event as specified in 3GPP standard document TS38.331.

[0123] According to some embodiments of this application, in response to receiving CHO configuration information, in step 913, the UE may transmit a feedback message to the source BS, such as an RRCReconfigurationComplete message.

[0124] In step 915, the UE may maintain its connection with the source BS and begin evaluating a set of execution conditions for a group of candidate cells. Before any execution conditions are met, the UE may execute the HO procedure upon receiving an HO command without CHO configuration, regardless of any previously received CHO configuration information. Otherwise, if at least one execution condition for at least one candidate cell is met, in step 917, the UE may detach from the source BS and execute a CHO procedure for a candidate cell determined (or selected) from at least one candidate cell. The determined candidate cell is the target cell. Since the candidate cell is selected based on MBS information associated with the CHO, the UE can only select the target cell from the candidate cells based on the execution conditions, which also increases the likelihood of MBS service and reduces MBS interruptions for the UE.

[0125] Embodiments of this application also propose a device for MBS. For example, Figure 10 A block diagram illustrating a device 1000 for MBS according to some embodiments of this application.

[0126] like Figure 10As shown, device 1000 may include at least one non-transitory computer-readable medium 1001, at least one receiving circuitry system 1002, at least one transmitting circuitry system 1004, and at least one processor 1006 coupled to the non-transitory computer-readable medium 1001, the receiving circuitry system 1002, and the transmitting circuitry system 1004. Device 1000 may be configured to perform... Figures 4 to 9 The network-side device (e.g., BS) of any of the methods described in the above, or configured to perform Figures 3 to 9 The remote unit (e.g., UE) of the method described in any of the above.

[0127] Although elements such as at least one processor 1006, transmitting circuitry system 1004, and receiving circuitry system 1002 are described in the singular in this figure, plural forms may be considered unless explicitly stated otherwise. In some embodiments of this application, receiving circuitry system 1002 and transmitting circuitry system 1004 may be combined into a single device, such as a transceiver. In some embodiments of this application, device 1000 may further include input devices, memory, and / or other components.

[0128] For example, in some embodiments of this application, the non-transitory computer-readable medium 1001 may store computer-executable instructions thereon to cause a processor to implement the methods concerning the UE as described above. For example, when executed, the computer-executable instructions cause the processor 1006 to interact with the receiving circuit system 1002 and the transmitting circuit system 1004 to perform... Figures 3 to 9 The steps concerning the UE described in any of them.

[0129] For example, in some embodiments of this application, the non-transitory computer-readable medium 1001 may store computer-executable instructions thereon to cause a processor to implement the methods regarding the BS as described above. For example, when executed, the computer-executable instructions cause the processor 1006 to interact with the receiving circuit system 1002 and the transmitting circuit system 1004 to perform... Figures 4 to 9 The steps concerning BS described in any of them.

[0130] The methods according to embodiments of this application can also be implemented on a programmable processor. However, the controller, flowchart, and modules can also be implemented on general-purpose or special-purpose computers, programmable microprocessors or microcontrollers and peripheral integrated circuit elements, integrated circuits, hardware electronics or logic circuits (e.g., discrete component circuits), programmable logic devices, etc. Generally, any device on which a finite state machine capable of implementing the flowcharts shown in the figures resides can be used to implement the processor functions of this application. For example, embodiments of this application provide an apparatus for an MBS that includes a processor and a memory. Computer-programmable instructions for implementing the method are stored in the memory, and the processor is configured to execute the computer-programmable instructions to implement the method. The method may be the method described above or other methods according to embodiments of this application.

[0131] Alternative embodiments preferably implement the methods of the embodiments of this application in a non-transitory computer-readable storage medium storing computer-programmable instructions. The instructions are preferably executed by a computer-executable component preferably integrated with a network security system. The non-transitory computer-readable storage medium can be stored on any suitable computer-readable medium, such as RAM, ROM, flash memory, EEPROM, optical storage devices (CD or DVD), hard disk drives, floppy disk drives, or any suitable device. The computer-executable component is preferably a processor, but the instructions may alternatively or additionally be executed by any suitable dedicated hardware device. For example, embodiments of this application provide a non-transitory computer-readable storage medium in which computer-programmable instructions are stored. The computer-programmable instructions are configured to implement the methods described above or other methods according to the embodiments of this application.

[0132] Furthermore, in this disclosure, relational terms such as "first," "second," etc., may be used only to distinguish one entity or action from another, and do not necessarily require or imply any actual such relationship or order between such entities or actions. The term "includes / including," or any other variations thereof, is intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements may include not only said elements but also other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further constraints, an element beginning with "a / an" or similar does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes said element. Furthermore, the term "another" is defined as at least a second or more.

[0133] While this disclosure has described specific embodiments therein, many alternatives, modifications, and variations will be apparent to those skilled in the art. For example, various components of the embodiments may be interchanged, added, or substituted in other embodiments. Furthermore, not all elements in each figure are essential for the operation of the disclosed embodiments. For example, those skilled in the art to which the disclosed embodiments pertain will be able to make and use the teachings of this disclosure by simply employing the elements of the independent claims. Therefore, the embodiments of this disclosure as described herein are intended to be illustrative and not restrictive. Various changes may be made without departing from the spirit and scope of this disclosure.

Claims

1. A user equipment (UE) comprising: Memory; as well as A processor coupled to the memory, the processor being configured such that the UE: Conditional handover (CHO) configuration information is received from the base station (BS), wherein the CHO configuration information indicates a set of execution conditions for a group of candidate cells, and each execution condition is associated with a candidate cell; Receive multicast and broadcast service MBS information associated with CHO from the BS; and A CHO process is performed to a target cell in the set of candidate cells in response to the satisfaction of at least one of the set of execution conditions, wherein the target cell is determined based on the set of execution conditions and the MBS information associated with the CHO.

2. The UE of claim 1, wherein the MBS information associated with the CHO is a cell list for MBS, the cell list comprising at least one of the following: List of cells that support MBS; A list of cells with ongoing MBS sessions; A list of cells with MBS Service / Session Area Identifier (SAI); or It provides a list of cells that are currently providing ongoing MBS sessions.

3. The UE of claim 2, wherein the processor is configured such that the UE: The MBS information associated with the CHO is received via a message for MBS configuration.

4. The UE of claim 1, wherein the MBS information associated with the CHO includes information about at least one of the MBS sessions or MBS bearers associated with each candidate cell, and includes at least one of the following: Is the ongoing MBS session being admitted by the candidate cell? Whether the ongoing MBS bearer has been admitted by the candidate cell; Whether the ongoing MBS session remains in the candidate cell; or Whether the ongoing MBS bearer remains in the candidate cell.

5. The UE of claim 4, wherein the processor is configured such that the UE: The MBS information associated with the CHO is received via a message for the CHO configuration information.

6. The UE of claim 4, wherein the processor is configured such that the UE determines the set of candidate cells based on the MBS information associated with the CHO, and determines the target cell from the set of candidate cells based on the set of execution conditions.

7. The UE of claim 1, wherein the MBS information associated with the CHO includes one or more of System Information Blocks (SIBs) or Multicast Control Channels (MCCHs) received from different cells.

8. A base station (BS), comprising: Memory; as well as A processor coupled to the memory, the processor being configured such that the BS: Determine the multicast and broadcast service MBS information associated with the conditional switching CHO; Transmit CHO configuration information to the User Equipment (UE), wherein the CHO configuration information indicates a set of execution conditions for a group of candidate cells, each execution condition being associated with a candidate cell; and The MBS information associated with the CHO is transmitted to the UE.

9. The BS of claim 8, wherein the MBS information associated with the CHO includes a cell list for MBS, the cell list containing at least one of the following: List of cells that support MBS; A list of cells with ongoing MBS sessions; A list of cells with MBS service / session area identifiers; or It provides a list of cells that are currently providing ongoing MBS sessions.

10. The BS of claim 9, wherein the processor is configured such that the BS: The MBS information associated with the CHO is transmitted via a message used for MBS configuration.

11. The BS of claim 8, wherein the MBS information associated with the CHO includes information about at least one of the MBS sessions or MBS bearers associated with each candidate cell, and includes at least one of the following: Is the ongoing MBS session being admitted by the candidate cell? Whether the ongoing MBS bearer has been admitted by the candidate cell; Whether the ongoing MBS session remains in the candidate cell; and Whether the ongoing MBS bearer remains in the candidate cell.

12. The BS of claim 11, wherein the processor is configured such that the BS: The MBS information associated with the CHO is transmitted via a message used to transmit the CHO configuration information.

13. The BS of claim 11, wherein the processor is configured such that the BS: The set of candidate cells is determined based on the MBS information associated with the CHO.

14. The BS of claim 11, wherein the processor is configured such that the BS: Receive the MBS information associated with CHO from the Operation, Management and Maintenance (OAM) team.

15. A method performed by a user equipment (UE), comprising: Conditional handover (CHO) configuration information is received from the base station (BS), wherein the CHO configuration information indicates a set of execution conditions for a group of candidate cells, and each execution condition is associated with a candidate cell; Receive multicast and broadcast service MBS information associated with CHO from the BS; and A CHO process is performed to a target cell in the set of candidate cells in response to the satisfaction of at least one of the set of execution conditions, wherein the target cell is determined based on the set of execution conditions and the MBS information associated with the CHO.

16. The method of claim 15, wherein the MBS information associated with the CHO is a cell list for MBS, the cell list comprising one or more of the following: List of cells that support MBS; A list of cells with ongoing MBS sessions; A list of cells with MBS Service / Session Area Identifier (SAI); or It provides a list of cells that are currently providing ongoing MBS sessions.

17. The method of claim 16, further comprising: The MBS information associated with the CHO is received via a message for MBS configuration.

18. The method of claim 16, wherein the MBS information associated with the CHO includes information about at least one of the MBS sessions or MBS bearers associated with each candidate cell, and includes one or more of the following: Is the ongoing MBS session being admitted by the candidate cell? Whether the ongoing MBS bearer has been admitted by the candidate cell; Whether the ongoing MBS session remains in the candidate cell; or Whether the ongoing MBS bearer remains in the candidate cell.

19. The method of claim 18, further comprising: The MBS information associated with the CHO is received via a message for the CHO configuration information.

20. The method of claim 18, further comprising determining the set of candidate cells based on the MBS information associated with the CHO, and determining the target cell from the set of candidate cells based on the set of execution conditions.

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