Method and apparatus for supporting reception of multicast service in inactive state

Abstract

The present disclosure relates to a method for supporting multicast reception of a user equipment (UE) in an RRCINACTIVE state. The method includes receiving, by a distributed unit (DU), indication information from a central unit (CU), and providing, by the DU, configuration information to the CU. The present disclosure also relates to a method for supporting multicast reception of a user equipment (UE) in an RRCINACTIVE state. The method includes receiving, by the UE, a configuration regarding multicast reception in the RRCINACTIVE state, and receiving, by the UE, multicast in the RRCINACTIVE state.

Description

[0001] This document relates generally to wireless communications, particularly fifth generation (5G) wireless communications, and more particularly to methods and apparatus for supporting reception of multicast services in an inactive state.

[0002] Multicast and Broadcast Service (MBS), which is considered one of the most prominent use cases of 5G New Radio (NR), provides reliable, low-latency and resource-efficient transmission for multiple terminals that need to receive the same content. Its main usage scenarios are mostly concentrated in congested areas such as concerts, stadiums and racecourses. On the one hand, there may be situations where the video needs to be synchronized to the terminal, and on the other hand, there may be situations where multiple perspectives are required. In addition, a large number of users in the same cell watch virtual reality (VR) live broadcasts at the same time, and push epidemic and disaster situations in specific areas through applications (APP) or TV.

[0003] An outstanding task is how to deal with the cell congestion problem. Considering that the number of UEs connected to a cell and the amount of services carried by a cell are limited, cell congestion may lead to the denial or reduction of transmission of other services or UEs.

[0004] In 5G NR, UE has three RRC states, namely RRC_CONNECTED, RRC_IDLE and RRC_INACTIVE. RRC_INACTIVE is a new state defined by 5G NR. When the UE enters the RRC_INACTIVE state, it will retain part of the context of the access network.

[0005] In the RRC_INACTIVE state, if there is data to be sent, it is necessary to transition to the RRC_CONNECTED state through the connection recovery process. The introduction of the RRC_INACTIVE state can not only save energy, but also maintain the delay of the control plane in control, that is, the UE can quickly enter the RRC_CONNECTED state, and the CP delay is lower compared to RRC_IDLE.

[0006] In the case of cell congestion or need for energy saving, one of the solutions to have or continue MBS multicast reception may be to transition the state to RRC_INACTIVE for some UEs to which MBS multicast has been applied. Such (multiple) UEs may transition from the RRC_CONNECTED state to the RRC_INACTIVE state to receive or continue receiving the multicast session.

[0007] In Rel-17 NR MBS, the PTM configuration delivery method is specified as follows:

[0008] For multicast, dedicated signaling is used for multicast only in Rel-17;

[0009] For broadcast, only SC-PTM-like signaling is used (for broadcast reception in other SCells, dedicated signaling for delivering SIBx is used).

[0010] In Rel-18, the requirement for multicast reception in RRC_INACTIVE was confirmed.

[0011] According to the present disclosure, a solution is proposed on how to enable a UE to receive or continue to receive an MBS service in an RRC_INACTIVE state.

[0012] This document relates to methods, systems, and devices for supporting reception of multicast services in an inactive state.

[0013] The present disclosure relates to a method for supporting multicast reception of a user equipment UE in an RRC_INACTIVE state, the method comprising: receiving indication information from a central unit CU by a distributed unit DU, and providing configuration information to the CU by the DU.

[0014] Various embodiments may preferably achieve the following features:

[0015] Preferably, the indication information from the CU to the DU is carried in the multicast context establishment request and / or the multicast context modification request.

[0016] Preferably, the indication information from the CU to the DU is carried in the broadcast context establishment request and / or the broadcast context modification request.

[0017] Preferably, the configuration information from the DU to the CU is carried in a multicast context establishment response and / or a multicast context modification response.

[0018] Preferably, the configuration information from the DU to the CU is carried in a broadcast context establishment response and / or a broadcast context modification response.

[0019] Preferably, the indication information from the CU to the DU indicates that (multiple) multicast services are transmitted for RRC_INACTIVE UEs, and / or the DU maintains point-to-multipoint PTM transmission available for (multiple) multicast services regardless of whether there are UEs in RRC_CONNECTED state.

[0020] Preferably, the indication information from the CU to the DU indicates that the DU configures a second set of PTM configurations for (multiple) multicast services to be provided via the multicast and broadcast service MBS control channel MCCH, and / or the DU configures and provides a second set of PTM configurations for (multiple) multicast services to be provided via the MCCH.

[0021] Preferably, the indication information from the CU to the DU indicates that the resources of the two sets of PTM configurations for the same multicast service are the same, and / or the DU configures and provides the PTM configuration through the MCCH based on the current PTM configuration, and the current PTM configuration is provided through dedicated signaling for (multiple) the same multicast services; and / or the CU indicates that the resources of the two sets of PTM configurations for the same multicast are the same, and provides a mapping relationship between the radio bearer RB index in the MCCH and the RB identification ID in the dedicated signaling for the same multicast through dedicated signaling.

[0022] Preferably, the configuration information from DU to CU indicates that the resources of the two sets of PTM configurations for the same multicast service are the same, and / or CU indicates that the resources of the two sets of PTM configurations for the same multicast are the same, and a mapping relationship between the RB index in the MCCH and the RB ID in the dedicated signaling for the same multicast is provided through dedicated signaling.

[0023] Preferably, the indication information from the CU to the DU indicates the multicast reception area setting for (multiple) multicast services sent for the RRC_INACTIVE UE, in particular, a notification area RNA area based on the radio access network (RAN) can be set as a multicast reception area, and / or the DU provides PTM configuration for (multiple) multicast services to all cells in the multicast reception area.

[0024] Preferably, the information of the multicast reception area includes at least one of the following:

[0025] Cell id list,

[0026] Cell frequency list,

[0027] multicast service id, or

[0028] Check whether the PTM configurations are the same.

[0029] Preferably, the indication information from the CU to the DU indicates a request for cell information related to multicast reception for the RRC_INACTIVE UE, and / or the DU provides the CU with cell information related to multicast reception.

[0030] Preferably, the indication information from the CU to the DU carries the collected cell information related to multicast reception to the DU.

[0031] Preferably, the cell information includes at least one of the following:

[0032] Cell ID,

[0033] Cell frequency,

[0034] The multicast service ID sent in this cell,

[0035] The PTM configuration for multicast sent in this cell,

[0036] Whether to support sending multicast to UE in RRC_INACTIVE state,

[0037] Whether the PTM configuration for multicast is delivered via MCCH, or

[0038] Whether the cell is congested.

[0039] The present disclosure also relates to a network node for supporting multicast reception of a user equipment UE in an RRC_INACTIVE state, the network node comprising a processor, the processor being configured to:

[0040] receiving an indication message from a central unit CU, and

[0041] Provide configuration information to CU.

[0042] Various embodiments may preferably achieve the following features:

[0043] Preferably, the network node is a distributed unit DU.

[0044] Preferably, the indication information from the CU to the network node is carried in a multicast context establishment request and / or a multicast context modification request.

[0045] Preferably, the indication information from the CU to the network node is carried in a broadcast context establishment request and / or a broadcast context modification request.

[0046] Preferably, the configuration information from the network node to the CU is carried in a multicast context establishment response and / or a multicast context modification response.

[0047] Preferably, the configuration information from the network node to the CU is carried in a broadcast context establishment response and / or a broadcast context modification response.

[0048] Preferably, the indication information from the CU to the network node indicates that (multiple) multicast services are sent for RRC_INACTIVE UEs, and / or the processor of the network node is configured to maintain point-to-multipoint PTM transmission available for (multiple) multicast services regardless of whether there are UEs in RRC_CONNECTED state.

[0049] Preferably, the indication information from the CU to the network node indicates that the processor of the network node is configured to: configure a second set of PTM configurations for (multiple) multicast services to be provided via the multicast and broadcast service MBS control channel MCCH, and / or the processor of the network node is configured to: configure and provide a second set of PTM configurations for (multiple) multicast services to be provided via the MCCH.

[0050] Preferably, the indication information from the CU to the network node indicates that the resources of the two sets of PTM configurations for the same multicast service are the same, and / or the processor of the network node is configured to: configure and provide the PTM configuration through the MCCH based on the current PTM configuration, and the current PTM configuration is provided through dedicated signaling for (multiple) the same multicast services; and / or the CU is configured to: indicate that the resources of the two sets of PTM configurations for the same multicast are the same, and provide a mapping relationship between the RB index in the MCCH and the RB ID in the dedicated signaling for the same multicast through dedicated signaling.

[0051] Preferably, the configuration information from the network node to the CU indicates that the resources of the two sets of PTM configurations for the same multicast service are the same, and / or the CU is configured to: indicate that the resources of the two sets of PTM configurations for the same multicast are the same, and provide a mapping relationship between the radio bearer RB index in the MCCH and the RB ID in the dedicated signaling for the same multicast through dedicated signaling.

[0052] Preferably, the indication information from the CU to the network node indicates the multicast reception area setting for (multiple) multicast services sent for RRC_INACTIVE UE, in particular, the RAN-based notification area RNA area can be set as the multicast reception area, and / or the processor of the network node is configured to: provide PTM configuration for (multiple) multicast services to all cells in the multicast reception area.

[0053] Preferably, the information of the multicast reception area includes at least one of the following:

[0054] Cell id list,

[0055] Cell frequency list,

[0056] multicast service id, or

[0057] Check whether the PTM configurations are the same.

[0058] Preferably, the indication information from the CU to the network node indicates a request for cell information related to multicast reception for RRC_INACTIVE UE, and / or the processor of the network node is configured to provide the CU with cell information related to multicast reception.

[0059] Preferably, the indication information from the CU to the network node carries the collected cell information related to multicast reception to the network node.

[0060] Preferably, the cell information includes at least one of the following:

[0061] Cell ID,

[0062] Cell frequency,

[0063] The multicast service ID sent in this cell,

[0064] The PTM configuration for multicast sent in this cell,

[0065] Whether to support sending multicast to UE in RRC_INACTIVE state,

[0066] Whether the PTM configuration for multicast is delivered via MCCH, or

[0067] Whether the cell is congested.

[0068] The present disclosure also relates to a method for supporting multicast reception of a user equipment UE in an RRC_INACTIVE state, the method comprising:

[0069] receiving, by the UE, configuration for multicast reception in the RRC_INACTIVE state, and

[0070] Multicast is received by the UE in RRC_INACTIVE state.

[0071] Various embodiments may preferably achieve the following features:

[0072] Preferably, the configuration is carried in a Radio Resource Control RRC reconfiguration and / or RRC release and / or a Multicast and Broadcast Service MBS Control Channel MCCH.

[0073] Preferably, the configuration includes indication information indicating that the point-to-multipoint PTM configuration is provided through a multicast and broadcast service MBS control channel MCCH for multicast sent in an RRC_INACTIVE state.

[0074] Preferably, the configuration indicates that the resources of the two PTM configurations used for the same multicast are the same, and carries a mapping relationship between the RB index in the MCCH and the RB ID in the dedicated signaling used for the same multicast, and / or the UE modifies the MRB ID according to the mapping relationship, and / or the UE receives the multicast using the modified MRB.

[0075] Preferably, the configuration carries a list of neighboring cell information about multicast reception in the RRC_INACTIVE state.

[0076] Preferably, the neighboring cell information includes at least one of the following:

[0077] Cell ID,

[0078] The cell frequencies that are providing MBS multicast services, especially the cell-defined SSB CD-SSB,

[0079] Whether to support sending multicast to UE in RRC_INACTIVE state,

[0080] Whether to deliver PTM configuration for multicast via MCCH,

[0081] Whether the PTM configuration for the same multicast is the same as the current cell, or

[0082] Whether the cell is congested.

[0083] Preferably, the UE applies a normal cell reselection rule with at least one of the following modifications:

[0084] - UEs that are receiving or interested in receiving these MBS service(s) while camping on a frequency providing these MBS service(s) are allowed to give the highest priority to this frequency,

[0085] - the UE considers the frequency providing the same PTM configuration with respect to the multicast service(s) the UE is receiving as the highest priority,

[0086] - the UE considers the uncongested frequency as the highest priority, or

[0087] - When the MBS multicast service(s) of interest to the UE are no longer available, in particular after a session ends, or when the UE is no longer interested in receiving the multicast service(s), the UE no longer prioritizes the frequencies providing these multicast service(s).

[0088] Preferably, the neighbor cell information shows that the PTM configurations in the last serving cell and the reselected cell are the same, and / or the UE receives multicast using the PTM configuration acquired from the last serving cell after cell reselection.

[0089] Preferably, the neighbor cell information shows that the PTM configuration in the reselected cell is delivered via MCCH, and / or the UE monitors MCCH after cell reselection to obtain the PTM configuration and its update.

[0090] Preferably, the neighbor cell information shows no congestion and / or MBS service transmission is not supported in RRC_INAVTIVE, and / or PTM configuration is not delivered by MCCH in the reselected cell, and / or the UE triggers the RRC recovery procedure after cell reselection.

[0091] Preferably, when there is no information about the reselected cell, the method further comprises:

[0092] - The UE monitors the MCCH to obtain the PTM configuration, and if the PTM configuration cannot be obtained, the UE triggers the RRC recovery procedure, or

[0093] - The UE triggers the RRC recovery procedure to obtain the PTM configuration.

[0094] Preferably, the multicast for the UE in the RRC_INACTIVE state further includes at least one of the following:

[0095] -resumeCause is used for requesting multicast configuration update. The resumeCause is carried in the RRC resume request.

[0096] -resumeCause is used for multicast service request. The resumeCause is carried in the RRC resume request.

[0097] - A new access class is added for multicast configuration update / multicast service request requests, the new access class has a higher priority and the associated barring factors are specifically configured to always allow access,

[0098] - always skip the barring check process and access directly, especially by reusing access categories, or

[0099] -Skip the Unified Access Control (UAC) process and access directly.

[0100] The present disclosure also relates to a user equipment UE supporting multicast reception in an RRC_INACTIVE state, the UE comprising a processor, the processor being configured to:

[0101] receiving configuration regarding multicast reception in the RRC_INACTIVE state, and

[0102] Receiving multicast in RRC_INACTIVE state.

[0103] Preferably, the configuration is carried in a radio resource control RRC reconfiguration and / or RRC release and / or an MBS control channel MCCH.

[0104] Preferably, the configuration includes indication information, wherein the indication information indicates that the point-to-multipoint PTM configuration is provided through the MBS control channel MCCH for multicast sent in the RRC_INACTIVE state.

[0105] Preferably, the configuration indicates that the resources of the two PTM configurations for the same multicast are the same, and carries a mapping relationship between the radio bearer RB index in the MCCH and the RB ID in the dedicated signaling for the same multicast, and / or the UE's processor is configured to modify the MRB ID according to the mapping relationship, and / or the UE's processor is configured to receive the multicast using the modified MRB.

[0106] Preferably, the configuration carries a list of neighboring cell information about multicast reception in the RRC_INACTIVE state.

[0107] Preferably, the neighboring cell information includes at least one of the following:

[0108] Cell ID,

[0109] The cell frequencies that provide MBS multicast services, especially the cell-defined SSB CD-SSB,

[0110] Whether to support sending multicast to UE in RRC_INACTIVE state,

[0111] Whether to deliver PTM configuration for multicast via MCCH,

[0112] Whether the PTM configuration for the same multicast is the same as the current cell, or

[0113] Whether the cell is congested.

[0114] Preferably, the processor of the UE is configured to apply the normal cell reselection rule with at least one of the following modifications:

[0115] - a processor of a UE that is receiving or interested in receiving these MBS service(s) while camping on a frequency providing these MBS service(s) is configured to be allowed to give the frequency the highest priority,

[0116] - the processor of the UE is configured to: consider the frequency providing the same PTM configuration with respect to the multicast service(s) being received by the UE as the highest priority,

[0117] - the processor of the UE is configured to consider the uncongested frequency as the highest priority, or

[0118] -When the MBS multicast service(s) of interest to the UE are no longer available, in particular after a session ends, or when the UE is no longer interested in receiving the multicast service(s), the UE's processor is configured to de-prioritize the frequencies providing these multicast service(s).

[0119] Preferably, the neighbor cell information shows that the PTM configurations in the last serving cell and the reselected cell are the same, and / or wherein the processor of the UE is configured to receive the multicast using the PTM configuration acquired from the last serving cell after cell reselection.

[0120] Preferably, the neighbor cell information shows that the PTM configuration in the reselected cell is delivered via MCCH, and / or the processor of the UE is configured to: monitor the MCCH after cell reselection to obtain the PTM configuration and its update.

[0121] Preferably, the neighbor cell information shows no congestion and / or MBS service transmission is not supported in RRC_INACTIVE state and / or PTM configuration is not delivered over MCCH in the reselected cell, and / or the UE's processor is configured to trigger an RRC recovery procedure after cell reselection.

[0122] Preferably, when there is no information about the reselected cell, the processor of the UE is configured to:

[0123] - monitor the MCCH to obtain the PTM configuration and trigger the RRC recovery procedure if the PTM configuration cannot be obtained, or

[0124] - Trigger the RRC recovery procedure to obtain the PTM configuration.

[0125] Preferably, the multicast for the UE in the RRC_INACTIVE state further includes at least one of the following:

[0126] -resumeCause is used for requesting multicast configuration update. The resumeCause is carried in the RRC resume request.

[0127] -resumeCause is used for multicast service request. The resumeCause is carried in the RRC resume request.

[0128] - A new access class is added for multicast configuration update / multicast service request requests, the new access class has a higher priority and the associated barring factors are specifically configured to always allow access,

[0129] - always skip the barring check process and access directly, especially by reusing access categories, or

[0130] -Skip the Unified Access Control (UAC) process and access directly.

[0131] The present disclosure relates to a computer program product, which includes a computer-readable program medium code stored thereon, and when the code is executed by a processor, the processor implements the wireless communication method described in any one of the aforementioned methods.

[0132] The exemplary embodiments disclosed herein are intended to provide features that will become apparent by reference to the following description when taken in conjunction with the accompanying drawings. According to various embodiments, exemplary systems, methods, devices, and computer program products are disclosed herein. However, it should be understood that these embodiments are presented by way of example and not limitation, and it will be apparent to those of ordinary skill in the art who read this disclosure that various modifications may be made to the disclosed embodiments while remaining within the scope of this disclosure.

[0133] Therefore, the present disclosure is not limited to the exemplary embodiments and applications described and illustrated herein. In addition, the specific order and / or hierarchy of steps in the methods disclosed herein are merely exemplary methods. Based on design preferences, the specific order or hierarchy of steps of the disclosed methods or processes can be rearranged while remaining within the scope of the present disclosure. Therefore, it will be understood by those of ordinary skill in the art that the methods and techniques disclosed herein present various steps or actions in a sample order, and unless otherwise expressly stated, the present disclosure is not limited to the specific order or hierarchy presented.

[0134] The above and other aspects and implementations thereof are described in more detail in the drawings, the description and the claims.

[0135] Figure 1 An example of a schematic diagram of a wireless terminal according to an embodiment of the present disclosure is shown.

[0136] Figure 2 An example of a schematic diagram of a wireless network node according to an embodiment of the present disclosure is shown.

[0137] Figure 3 and Figure 4 A flow chart of a method according to some embodiments of the present disclosure is shown.

[0138] In one embodiment, the network node may refer to a distributed unit DU. DU may also be referred to as a gNB-DU. The network node may also refer to a central unit CU. CU may also be referred to as a gNB-CU.

[0139] UE stands for User Equipment and may also be referred to as an example of a node.

[0140] F1, Uu and Xn refer to the corresponding interfaces.

[0141] TMGI stands for Temporary Mobility Group Entity.

[0142] MCCH stands for MBS (Multicast and Broadcast Service) Control Channel.

[0143] MRB stands for MBS Radio Bearer.

[0144] The RRC_INACTIVE state may refer to an inactive state of the UE. The RRC_CONNECTED state may refer to a connected state of the UE. RRC stands for Radio Resource Control.

[0145] Aspect 1: F1 signaling

[0146] Support multicast reception for RRC_INACTIVE UEs

[0147] In the conventional configuration method, due to the state transition of (multiple) UEs that are receiving (multiple) multicast services, the gNB-DU (gNB = next generation nodeB, i.e., base station; gNB distributed unit) may stop PTM transmission (point-to-multipoint transmission) or switch to PTP transmission (point-to-point transmission) for certain (multiple) multicast services.

[0148] To avoid the gNB-DU from performing the same operation for the multicast service(s) to be received by the UE in RRC_INACTIVE, indication information is carried in the F1 signaling from the CU to the DU to indicate that PTM transmission of the multicast service is retained regardless of the state of the UE(s).

[0149] In one embodiment:

[0150] The indication information is carried in the multicast context establishment request to indicate which multicast service(s) are to be continued to be received by the (multiple) UEs in RRC_INACTIVE. When the DU receives the indication information, the DU shall maintain PTM transmission available for the marked (multiple) multicast service(s), regardless of the state of the (multiple) UEs.

[0151] Support for PTM configuration delivered by MCCH (MBS Control Channel) for RRC_INACTIVE UEs

[0152] To support modification and update of PTM configurations for RRC_INACTIVE UEs, a second set of PTM configurations may be delivered over the MCCH for the multicast service(s).

[0153] To support MCCH to deliver PTM configuration for (multiple) multicast services, indication information is carried in the F1 signaling from CU to DU to indicate that the PTM configuration is delivered via MCCH, which is configured for multicast reception of (multiple) RRC_INACTIVE UEs.

[0154] In one embodiment:

[0155] The indication information is carried in the multicast context establishment request to indicate the PTM configurations for multicast services sent for UEs in RRC_INACTIVE to be delivered via MCCH. When the DU receives the indication information, the DU shall generate a second set of PTM configurations for such multicast service(s) to be delivered via MCCH.

[0156] In one embodiment:

[0157] The indication information is carried in the multicast and broadcast context establishment request to indicate the PTM configurations for multicast services sent for UEs in RRC_INACTIVE delivered over MCCH. When the DU receives the indication information, the DU shall generate a set of PTM configurations for such multicast service(s) delivered over MCCH.

[0158] In one embodiment:

[0159] The CU instructs the DU to configure the PTM configuration of the multicast service(s) by triggering the broadcast MBS session establishment procedure.

[0160] Configuration delivered via MCCH and dedicated signaling uses the same radio resources for the same multicast

[0161] The configuration delivered through MCCH and dedicated signaling uses the same radio resources for the same multicast, ie the same TMGI (Temporary Mobile Group Entity).

[0162] For the same service, the relationship between the configuration delivered by MCCH and the configuration delivered by dedicated signaling is: the resources are the same, and there is a mapping relationship between the RB index (MCCH) and the RB ID (dedicated signaling).

[0163] Here, RB stands for Radio Bearer.

[0164] When the UE receives two sets of PTM configurations from dedicated signaling and MCCH of the same TMGI (Temporary Mobile Group Entity) consecutively, the configuration release and re-establishment procedures will be performed according to the conventional method.

[0165] In order to ensure the continuity of multicast reception and reduce data interruption caused by configuration switching, one solution is to configure the same resources for two sets of PTM configurations for the same TMGI.

[0166] In one embodiment:

[0167] The resources of the two groups of PTM configurations for the same multicast service are the same as the default resources.

[0168] After the CU instructs the DU to configure the second set of PTM configurations for the multicast service(s), the DU shall configure the PTM configurations based on the configurations delivered by dedicated signaling and provide them to the UE(s) through the MCCH.

[0169] In one embodiment:

[0170] To support that the configurations delivered via MCCH and dedicated signaling are related to the same TMGI, indication information is carried in the F1 signaling from the CU to the DU to indicate that the resources of the two groups of PTM configurations for the same TMGI are the same.

[0171] When the DU receives the indication information, the DU will generate a set of PTM configurations delivered through the MCCH based on the corresponding PTM configurations delivered by dedicated signaling.

[0172] For resource configuration, the DU allocates the same resources for the configuration announced by the MCCH and the configuration announced by the corresponding dedicated signaling.

[0173] The indication information is carried in the multicast context establishment request / multicast context modification request / broadcast context establishment request / broadcast context modification request. Note that in the present disclosure, " / " may mean "and / or".

[0174] For the method of delivering the mapping relationship between RB index and RB ID, the CU provides the mapping relationship between two sets of PTM configurations for the same multicast service through dedicated signaling.

[0175] In one embodiment:

[0176] The resources of two sets of PTM configurations for the same multicast service may be configured to be the same by the DU.

[0177] Indication information is sent from the DU to the CU to indicate that the resources of two sets of PTM configurations for the same multicast service are the same.

[0178] The CU provides the relationship between two sets of PTM configurations for the same multicast service through dedicated signaling.

[0179] The indication information is carried in the multicast context establishment response / multicast context modification response / broadcast context establishment response / broadcast context modification response.

[0180] Support multicast reception area for RRC_INACTIVE UEs

[0181] In order to reduce the frequency of UE state transition, the concept of multicast reception area is proposed.

[0182] The definition of the multicast reception area is described below.

[0183] A multicast reception zone can be defined for one service or for all services in the zone.

[0184] In one embodiment (by service):

[0185] The area can be per service, that is, all cells in the area are sending the multicast service. When the UE moves in the area, it does not need to return to the RRC_CONNECTED state to request the multicast service. For the multicast service, the PTM configuration of the cells in the area can be the same or different.

[0186] In one embodiment (all services):

[0187] The area may also contain all multicast services sent by cells in the area that are inactive, i.e., each cell in the area sends all services that have been sent for RRC_INACTIVE UEs in the area. When the UE moves in the area, it does not need to return to the RRC_CONNECTED state to request multicast services. For the same multicast service, the PTM configurations of the cells in the area may be the same or different.

[0188] The range of the multicast reception area is described below.

[0189] There is a need to discuss which cells are included in the multicast reception area. There are several options for this:

[0190] -Cells in the same DU (within DU)

[0191] -Cells in different DUs but in the same CU (between DUs but within CU)

[0192] -Cells in different gNBs (inter-gNB)

[0193] In one embodiment (inside DU)

[0194] The scope of the area may be specified by the gNB-CU or gNB-DU. For example, it may be specified based on factors such as geographical location, UE distribution, and service distribution.

[0195] In one embodiment:

[0196] The scope of the multicast reception area is specified by the gNB-CU.

[0197] Indication information is sent from the CU to the DU to indicate which cells are included in the area of ​​the multicast service. For example, a RAN-based notification area (RNA area) can be set as a multicast reception area.

[0198] The indication information is carried in the multicast context establishment request / multicast context modification request / broadcast context establishment request / broadcast context modification request.

[0199] The DU will provide the PTM configuration for this service to all cells in the area.

[0200] There are two options for the delivery method of the multicast reception zone settings:

[0201] Option 1: DU provides the setting of multicast reception area through MCCH.

[0202] Option 2: The CU provides the setting of the multicast reception area through dedicated signaling.

[0203] In one example: the scope of the multicast reception area is specified by the gNB-DU.

[0204] There are two options for the delivery method of the multicast reception zone settings:

[0205] Option 1: DU provides the setting of multicast reception area through MCCH.

[0206] Option 2: The CU provides the setting of the multicast reception area through dedicated signaling.

[0207] For option 2, the indication information from the DU to the CU indicates the multicast reception area setting of (multiple) multicast services. For example, the RNA area can be set as the multicast reception area.

[0208] The indication information is carried in the multicast context establishment response / multicast context modification response / broadcast context establishment response / broadcast context modification response.

[0209] In one embodiment:

[0210] The information of the multicast receiving area includes:

[0211] Cell ID List

[0212] Cell frequency list

[0213] multicast service id, or

[0214] Are the PTM configurations the same?

[0215] Support neighboring cell information for RRC_INACTIVE UE

[0216] For a UE in RRC_INACTIVE state that is receiving multicast, a key issue is how to support mobility. Some information about neighboring cells can be provided to the UE to better perform cell reselection.

[0217] Neighboring cell information format

[0218] In one embodiment (by service)

[0219] A cell list is associated with each multicast received in RRC_INACTIVE state. The cells in the list are currently sending the multicast.

[0220] In another embodiment (by cell)

[0221] For each neighboring cell, there is a multicast list received in the cell. The multicast services in the list are received in the cell.

[0222] Context of Neighbor Cell Information Option

[0223] -Cell ID

[0224] - The frequency of the cell that is providing the MBS multicast service (e.g., cell-defined SSB, CD-SSB)

[0225] - Whether to support sending multicast to UE in RRC_INACTIVE state

[0226] -Whether to deliver multicast PTM configuration via MCCH

[0227] -Whether the PTM configuration of the same multicast is the same as that of the current cell

[0228] - Is the cell congested?

[0229] Different neighboring cell information has different effects on the cell reselection process and behavior in the reselected cell.

[0230] Multicast neighboring cell range

[0231] For the generation of neighbor cell information, which cells need to be included is a key question. There are several options for this.

[0232] -Cells in the same DU (within DU)

[0233] -Cells in different DUs but in the same CU (between DUs but within CU)

[0234] -Cells in different gNBs (inter-gNB)

[0235] In one embodiment (inside DU)

[0236] There are two options for the delivery method of neighbor cell information:

[0237] Option 1: DU provides neighboring cell information via MCCH.

[0238] Option 2: The CU provides neighbor cell information through dedicated signaling.

[0239] For option 2, the indication information from DU to CU carries cell information related to multicast reception. The cell information is carried in the multicast context setup response / multicast context modification response / broadcast context setup response / broadcast context modification response. The CU provides the collected cell information to (multiple) UEs through dedicated signaling.

[0240] In one embodiment (between DUs but within CUs)

[0241] The indication information from the CU to the DU indicates a request for cell information related to multicast reception of the RRC_INACTIVE UE.

[0242] The indication information is carried in the multicast context establishment request / multicast context modification request / broadcast context establishment request / broadcast context modification request.

[0243] The DU sends cell information related to multicast reception to the CU.

[0244] The cell information is carried in the multicast context establishment response / multicast context modification response / broadcast context establishment response / broadcast context modification response.

[0245] There are two options for the delivery method of neighbor cell information:

[0246] Option 1: DU provides neighboring cell information via MCCH.

[0247] Option 2: The CU provides neighbor cell information through dedicated signaling.

[0248] For option 1, the CU sends the collected cell information related to multicast reception to the DU.

[0249] The collected cell information is carried in a multicast context establishment request / multicast context modification request / multicast distribution establishment response / broadcast context establishment request / broadcast context modification request.

[0250] In one embodiment:

[0251] The cell information includes:

[0252] -Cell ID

[0253] -Cell frequency

[0254] - Multicast service ID sent in this cell

[0255] - PTM configuration for multicast sent in this cell

[0256] - Whether to support sending multicast to UE in RRC_INACTIVE state

[0257] -Whether to deliver multicast PTM configuration via MCCH

[0258] - Is the cell congested?

[0259] Aspect 2: Uu interface

[0260] Support multicast reception for RRC_INACTIVE UEs

[0261] To support multicast reception for UEs in RRC_INACTIVE, indication information is received from the gNB indicating that (multiple) multicast services are sent in RRC_INACTIVE.

[0262] In one embodiment:

[0263] The indication information is carried in the RRC reconfiguration / RRC release.

[0264] After receiving the indication information, the UE will receive (multiple) corresponding multicast services in the RRC_INACTIVE state.

[0265] Support PTM configuration for MCCH delivery for RRC_INACTIVE UE

[0266] To support modification and update of PTM configuration for RRC_INACTIVE UEs, a second set of PTM configurations may be delivered via MCCH for (multiple) multicast services. An indication is received from the gNB indicating that the PTM configurations are delivered by MCCH, which is configured for multicast reception in RRC_INACTIVE.

[0267] In one embodiment:

[0268] The indication information is carried in the RRC reconfiguration / RRC release.

[0269] After receiving the indication information, the UE will obtain the PTM configuration through the MCCH.

[0270] Configuration delivered via MCCH and dedicated signaling uses the same radio resources for the same multicast

[0271] The configuration delivered through MCCH and dedicated signaling uses the same radio resources for the same multicast, ie the same TMGI (Temporary Mobile Group Entity).

[0272] When the UE receives two sets of PTM configurations from dedicated signaling and MCCH of the same TMGI consecutively, the configuration release and re-establishment procedures will be performed according to the conventional method.

[0273] In order to ensure the continuity of multicast reception and reduce data interruption caused by configuration switching, one solution is to configure the same resources for two sets of PTM configurations for the same TMGI. The relationship between the two sets of PTM configurations is delivered by the gNB.

[0274] The multicast RBs provided by the MCCH are assigned indexes, and the corresponding mapping relationship with the RB IDs of the dedicated signaling is indicated / carried in the configuration information. The resources in the two groups of PTM configurations of the same TMGI are the same.

[0275] In one embodiment:

[0276] Indication information is carried in the RRC reconfiguration, which indicates that the resources of the two groups of PTM configurations of the same multicast sent in RRC_INACTIVE are the same, and provides a mapping relationship between the RB index in the MCCH sent in RRC_INACTIVE and the RB ID in the dedicated signaling for the same multicast.

[0277] After receiving the indication information, the UE only needs to modify the MRB (MBS Radio Bearer) ID configured by the MCCH according to the mapping relationship, and continue to receive multicast using the PTM configuration. The UE will start monitoring the MCCH to obtain updates of the PTM configuration.

[0278] In one embodiment:

[0279] Indication information is carried in the RRC release, which indicates that the resources of the two groups of PTM configurations of the same multicast sent in RRC_INACTIVE are the same, and provides a mapping relationship between the RB index in the MCCH sent in RRC_INACTIVE and the RB ID in the dedicated signaling for the same multicast.

[0280] After receiving the indication information, the UE will not suspend the corresponding PTM configuration, but will only modify the MRB ID configured by the MCCH according to the mapping relationship, and continue to receive multicast using the PTM configuration. The UE will also start monitoring the MCCH to obtain updates to the PTM configuration.

[0281] Support neighboring cell information for RRC_INACTIVE UE

[0282] For a UE in RRC_INACTIVE state that is receiving multicast, a key issue is how to support mobility. Some information about neighboring cells can be provided to the UE to better perform cell reselection.

[0283] The format of the neighbor cell information is described below.

[0284] In one embodiment (by service)

[0285] A cell list is associated with each multicast received in RRC_INACTIVE state. The cells in the list are currently sending the multicast.

[0286] In another embodiment (by cell)

[0287] For each neighboring cell, there is a multicast list received in the cell. The multicast services in the list are received in the cell.

[0288] The context of the Neighbor Cell Information option includes:

[0289] -Cell ID

[0290] -Cell frequency that is providing MBS multicast service (e.g. CD-SSB)

[0291] - Whether to support sending multicast to UE in RRC_INACTIVE state

[0292] -Whether to deliver multicast PTM configuration via MCCH

[0293] -Whether the PTM configuration of the same multicast is the same as that of the current cell

[0294] - Is the cell congested?

[0295] Different neighboring cell information has different effects on the cell reselection process and behavior in the reselected cell.

[0296] The following describes the method of delivering the neighbor cell information.

[0297] In one embodiment:

[0298] The RRC reconfiguration message carries neighboring cell information and its updates.

[0299] The UE obtains it to assist in cell reselection.

[0300] In one embodiment:

[0301] The RRC release message carries the neighboring cell information.

[0302] The UE obtains it to assist in cell reselection.

[0303] In one embodiment:

[0304] There are two options for MCCH to carry neighbor cell information:

[0305] Option 1: Neighbor cell information is always delivered by MCCH without any indication.

[0306] Option 2: There is an indication delivered by dedicated signaling, which instructs the UE to obtain neighbor cell information through MCCH.

[0307] For option 2, the indication information is carried in the RRC reconfiguration / RRC release.

[0308] The UE receives neighbor cell information and its update from the MCCH according to the indication information.

[0309] The cell information process is described below.

[0310] In order to ensure the continuity of multicast reception in RRC_INACTIVE as much as possible, the UE performs cell reselection based on the neighboring cell information.

[0311] In one embodiment:

[0312] According to the neighbor cell information list, for cell reselection, a UE that is receiving or interested in receiving the MBS service(s) while camping on a frequency providing the MBS service(s) is allowed to give the frequency the highest priority.

[0313] In one embodiment:

[0314] Based on the neighbor cell information list, for cell reselection, when the MBS multicast service(s) of interest to the UE are no longer available (after the session ends), or when the UE is no longer interested in receiving the multicast service(s), the UE no longer prioritizes the frequencies providing these multicast services(s).

[0315] In one embodiment:

[0316] According to the neighbor cell information list, for cell reselection, the UE may consider the frequency providing the same PTM configuration with respect to the multicast service(s) that the UE is receiving as the highest priority.

[0317] In one embodiment:

[0318] According to the neighbor cell information list, for cell reselection, the UE may consider the non-congested frequency as the highest priority.

[0319] The following describes the UE behavior in the reselected cell.

[0320] Different neighbor cell information will have different effects on the UE behavior in the reselected cell.

[0321] In one embodiment (same PTM configuration):

[0322] If the neighbor cell information shows that the PTM configuration of the MBS service(s) being received or interested in being received in the reselected cell is the same as the last serving cell, the UE will continue to receive the MBS service(s) using the PTM configuration acquired from the last serving cell.

[0323] If the neighbor cell information also shows that the PTM configuration is obtained from the MCCH in the reselected cell, the UE will start monitoring the MCCH to obtain updates of the PTM configuration.

[0324] Otherwise, if the neighbor cell information shows that the PTM configuration is not obtained from the MCCH in the reselected cell, when the UE cannot receive (multiple) MBS services or the reception quality is not good enough, it will trigger the RRC recovery procedure to update the PTM configuration.

[0325] In one embodiment (PTM configuration is different and delivered by MCCH):

[0326] If the neighbor cell information shows that the PTM configuration of the (multiple) MBS service being received or interested in being received in the reselected cell is different from that of the last serving cell, but can be obtained from the MCCH, the UE will first start monitoring the MCCH to obtain the PTM configuration after completing the cell reselection process. And then receive the (multiple) MBS service using the obtained PTM configuration.

[0327] In one embodiment (non-congested / unsupported MBS service transmission in RRC_INACTIVE / PTM configuration is not delivered by MCCH)

[0328] If the neighbor cell information shows that the reselected cell is not congested / does not support (multiple) MBS service transmission / does not deliver PTM configuration through MCCH in RRC_INACTIVE, the UE shall first trigger the RRC recovery procedure after completing the cell reselection procedure.

[0329] If the reselected cell is not congested, it is reasonable for the UE to resume the RRC connection in order to ensure the QoS of the MBS service. However, if the neighbor cell information also shows that the reselected cell delivers PTM configuration via MCCH for (multiple) MBS services that the UE is receiving or interested in receiving, it is up to the UE to decide whether to resume the RRC connection for (multiple) MBS service reception or remain in RRC_INACTIVE to obtain PTM configuration via MCCH.

[0330] If the reselected cell does not support (multiple) MBS service transmission in RRC_INACTIVE, the UE can only resume the RRC connection for (multiple) MBS service reception.

[0331] If the reselected cell does not deliver the PTM configuration via MCCH, the UE can only trigger the RRC recovery procedure to receive with the PTM configuration. However, the PTM configuration is obtained from dedicated signaling on the network. If the network is congested, it can deliver the PTM configuration via the RRC release message. If the network is not congested, the UE will be allowed to resume the RRC connection and obtain the PTM configuration from the RRC reconfiguration message.

[0332] In one embodiment (other)

[0333] The UE behavior in the reselected cell is associated with the delivery method of the PTM configuration. If the network always delivers the PTM configuration via dedicated signaling, the UE will always trigger the RRC recovery procedure after cell reselection. If the network always delivers the PTM configuration via MCCH, the UE will always start monitoring the MCCH after cell reselection.

[0334] However, if the delivery method of the PTM configuration is configurable, the UE will try to infer from the neighbor cell information whether the reselected cell delivers the PTM configuration via dedicated signaling or MCCH. If the delivery method can be inferred, the UE will perform the corresponding procedure.

[0335] However, if the delivery method cannot be inferred from the neighbor cell information, it will be up to the UE to first decide whether to monitor the MCCH or trigger the RRC recovery procedure after completing cell reselection.

[0336] There are two possibilities for UE behavior:

[0337] - Option 1: When the UE is unaware of the delivery method of the PTM configuration, the UE always triggers the RRC recovery procedure first after cell reselection.

[0338] - Option 2: When the UE is unaware of the delivery method of the PTM configuration, the UE always monitors the MCCH first after cell reselection.

[0339] For option 1, it may cause unnecessary RRC connection recovery, and congestion of the reselected cell may become severe, such as when the PTM configuration is delivered by MCCH in the reselected cell.

[0340] For option 2, it may result in a longer interruption time of the reception of MBS service(s), such as when the PTM configuration is delivered by dedicated signaling in the reselected cell.

[0341] Unified Access Control (UAC)

[0342] When the UE receives a multicast service in the RRC_INACTIVE state, it may trigger the RRC connection recovery procedure due to reasons such as configuration request, service request, etc.

[0343] In order to ensure the continuity of multicast data reception as much as possible, it is necessary to make some enhancements to the RRC connection recovery process, UAC process, etc.

[0344] An embodiment of RRC recovery is described below.

[0345] In one embodiment:

[0346] If the UE is receiving multicast services in RRC_INACTIVE, but due to some reasons (such as poor reception quality), the RRC recovery procedure is triggered to request a configuration update.

[0347] To ensure that the request can be quickly identified and responded to, the request for multicast configuration update uses resumeCause, which is carried in the RRC resume request.

[0348] Depending on the resumeCause, the gNB may respond to the request by issuing an RRC release carrying the PTM configuration regarding the multicast service(s) sent in RRC_INACTIVE.

[0349] In one embodiment:

[0350] If the reason why the UE triggers the RRC recovery process is to request a multicast service, the resumeCause is used for requesting the multicast service request, and the resumeCause is carried in the RRC recovery request.

[0351] Depending on resumeCause, the gNB may respond to the request first.

[0352] An embodiment of access control is described below.

[0353] In order to improve the continuity of multicast reception as much as possible in RRC_INACTIVE, it should be ensured that such requests are responded to quickly. Giving higher priority to the access control of such requests is a possible enhancement.

[0354] In one embodiment:

[0355] A new access category with higher priority is added, and the associated barring factor can be configured to always allow access.

[0356] In one embodiment:

[0357] Reuse access category '2', always skip the bar check procedure and access directly. In other words, always skip the bar check procedure and access directly, especially by reusing access category. There is always a bar check procedure before access, that is, the access may be delayed due to the indication of the gNB on the normal request. In some cases, AC2 can skip the bar check and access directly.

[0358] In one embodiment:

[0359] Access category '8' is reused and access is performed using the traditional mode.

[0360] In one embodiment:

[0361] Skip the UAC process and log in directly.

[0362] Figure 1A schematic diagram of a wireless terminal 10 according to an embodiment of the present disclosure is provided. The wireless terminal 10 may be a user equipment (UE), a mobile phone, a laptop, a tablet computer, an e-book, or a portable computer system, and is not limited thereto. The wireless terminal 10 may include a processor 100 such as a microprocessor or an application specific integrated circuit (ASIC), a storage unit 110, and a communication unit 120. The storage unit 110 may be any data storage device that stores program code 112 accessed and executed by the processor 100. Embodiments of the storage unit 110 include, but are not limited to, a subscriber identity module (SIM), a read-only memory (ROM), a flash memory, a random access memory (RAM), a hard disk, and an optical data storage device. The communication unit 120 may be a transceiver, and is used to send and receive signals (e.g., messages or packets) according to the processing results of the processor 100. In one embodiment, the communication unit 120 communicates with the user via a communication device 120. Figure 1 At least one antenna 122 is shown for transmitting and receiving signals.

[0363] In one embodiment, the storage unit 110 and the program code 112 may be omitted, and the processor 100 may include the storage unit with the stored program code.

[0364] Processor 100 may implement any of the steps in the exemplary embodiments on wireless terminal 10 , for example, by executing program code 112 .

[0365] The communication unit 120 may be a transceiver. Alternatively or additionally, the communication unit 120 may combine a transmitting unit and a receiving unit configured to respectively transmit and receive signals to and from a wireless network node (eg, a base station).

[0366] Figure 2A schematic diagram of a radio network node 20 according to an embodiment of the present disclosure is provided. The radio network node 20 may be a satellite, a base station (BS), a network entity, a mobility management entity (MME), a serving gateway (S-GW), a packet data network (PDN) gateway (P-GW), a radio access network (RAN) node, a next generation RAN (NG-RAN) node, a gNB, an eNB, a gNB central unit (gNB-CU), a gNB distributed unit (gNB-DU), a data network, a core network, or a radio network controller (RNC), and is not limited thereto. In addition, the radio network node 20 may include (execute) at least one network function, such as an access and mobility management function (AMF), a session management function (SMF), a user location function (UPF), a policy control function (PCF), an application function (AF), etc. The radio network node 20 may include a processor 200 such as a microprocessor or an ASIC, a storage unit 210, and a communication unit 220. The storage unit 210 may be any data storage device that stores a program code 212 accessed and executed by the processor 200. Examples of the storage unit 210 include, but are not limited to, a SIM, a ROM, a flash memory, a RAM, a hard disk, and an optical data storage device. The communication unit 220 may be a transceiver and is used to send and receive signals (e.g., messages or packets) according to the processing results of the processor 200. In one example, the communication unit 220 communicates with the processor 200 via Figure 2 At least one antenna 222 is shown for transmitting and receiving signals.

[0367] In one embodiment, storage unit 210 and program code 212 may be omitted. Processor 200 may include a storage unit with stored program code.

[0368] The processor 200 may implement any of the steps described in the example embodiments on the radio network node 20 , for example, via executing the program code 212 .

[0369] The communication unit 220 may be a transceiver. Alternatively or additionally, the communication unit 220 may combine a transmitting unit and a receiving unit configured to transmit and receive signals to and from a wireless terminal (eg, a user equipment or another wireless network node), respectively.

[0370] Figure 3 A flow chart of a method according to an embodiment of the present disclosure is shown. Specifically, Figure 3 A method for supporting multicast reception of a user equipment UE in RRC_INACTIVE state is shown. The method may be performed by a network node, in particular a distributed unit DU, which may include a processor.

[0371] The method comprises receiving 301 indication information by a distributed unit DU from a central unit CU, and providing 302 configuration information by the DU to the CU.

[0372] In one embodiment, the indication information from the CU to the DU is carried in the multicast context establishment request and / or the multicast context modification request.

[0373] In one embodiment, the indication information from the CU to the DU is carried in the broadcast context establishment request and / or the broadcast context modification request.

[0374] In one embodiment, the configuration information from the DU to the CU is carried in a multicast context establishment response and / or a multicast context modification response.

[0375] In one embodiment, the configuration information from the DU to the CU is carried in a broadcast context setup response and / or a broadcast context modification response.

[0376] In one embodiment, the indication information from the CU to the DU indicates that (multiple) multicast services are sent for RRC_INACTIVE UEs and / or the DU maintains point-to-multipoint PTM transmission available for (multiple) multicast services regardless of whether there is a UE in the RRC_CONNECTED state.

[0377] In one embodiment, the indication information from the CU to the DU indicates that: the DU is configured with a second set of PTM configurations for (multiple) multicast services to be provided by the multicast and broadcast service MBS control channel MCCH, and / or the DU is configured and provides a second set of PTM configurations for (multiple) multicast services to be provided by the MCCH.

[0378] In one embodiment, the indication information from the CU to the DU indicates that the resources of two sets of PTM configurations for the same multicast service are the same, and / or the DU configures and provides the PTM configuration through the MCCH based on the current PTM configuration provided by the dedicated signaling of (multiple) the same multicast services; and / or the CU indicates that the resources of two sets of PTM configurations for the same multicast are the same, and provides a mapping relationship between the radio bearer RB index in the MCCH and the RB ID in the dedicated signaling for the same multicast through dedicated signaling.

[0379] In one embodiment, the configuration information from the DU to the CU indicates that the resources of the two groups of PTM configurations for the same multicast service are the same, and / or the CU indicates that the resources of the two groups of PTM configurations for the same multicast are the same, and a mapping relationship between the RB index in the MCCH and the RB ID in the dedicated signaling for the same multicast is provided through dedicated signaling.

[0380] In one embodiment, the indication information from the CU to the DU indicates the multicast reception area setting for (multiple) multicast services sent for the RRC_INACTIVE UE, in particular, the RAN-based notification area RNA area can be set as the multicast reception area, and / or the DU provides the PTM configuration of (multiple) multicast services to all cells in the multicast reception area.

[0381] In one embodiment, the information of the multicast reception area includes at least one of the following:

[0382] Cell id list,

[0383] Cell frequency list,

[0384] multicast service id, or

[0385] Check whether the PTM configurations are the same.

[0386] In one embodiment, the indication information from the CU to the DU indicates a request for cell information related to multicast reception of the RRC_INACTIVE UE, and / or the DU provides the CU with cell information related to multicast reception.

[0387] In one embodiment, the indication information from the CU to the DU carries the collected cell information related to the multicast reception to the DU.

[0388] In one embodiment, the cell information includes at least one of the following:

[0389] Cell ID,

[0390] Cell frequency,

[0391] The multicast service ID sent in this cell,

[0392] The PTM configuration for multicast sent in this cell,

[0393] Whether to support sending multicast to UE in RRC_INACTIVE state,

[0394] Whether to deliver multicast PTM configuration via MCCH, or

[0395] Whether the cell is congested.

[0396] Figure 4 A flow chart of a method according to an embodiment of the present disclosure is shown. Specifically, Figure 4 A method for supporting multicast reception of a user equipment UE in an RRC_INACTIVE state is shown. The method may be performed by a user equipment UE which may include a processor.

[0397] The method comprises receiving 401, by the UE, configuration regarding multicast reception in the RRC_INACTIVE state, and receiving 402, by the UE, the multicast in the RRC_INACTIVE state.

[0398] In one embodiment, the configuration is carried in a Radio Resource Control RRC reconfiguration and / or RRC release and / or a Multicast and Broadcast Service MBS Control Channel MCCH.

[0399] In one embodiment, the configuration includes indication information indicating that the point-to-multipoint PTM configuration is provided through a multicast and broadcast service MBS control channel MCCH for multicast sent in an RRC_INACTIVE state.

[0400] In one embodiment, the configuration indicates that the resources of two PTM configurations for the same multicast are the same, and carries a mapping relationship between the RB index in the MCCH and the RB ID in the dedicated signaling for the same multicast, and / or the UE modifies the MRB ID according to the mapping relationship, and / or the UE receives the multicast using the modified MRB.

[0401] In one embodiment, the configuration carries a neighbor cell information list for multicast reception in RRC_INACTIVE state.

[0402] In one embodiment, the neighboring cell information includes at least one of the following:

[0403] Cell ID,

[0404] The cell frequencies that are providing MBS multicast services, especially cell-defined SSB, CD-SSB,

[0405] Whether to support sending multicast to UE in RRC_INACTIVE state,

[0406] Whether to deliver multicast PTM configuration via MCCH,

[0407] Is the PTM configuration of the same multicast the same as the current cell, or

[0408] Whether the cell is congested.

[0409] In one embodiment, the UE applies normal cell reselection rules with at least one of the following modifications:

[0410] - UEs that are receiving or interested in receiving these MBS service(s) while camping on a frequency providing these MBS service(s) are allowed to give the highest priority to this frequency,

[0411] - the UE considers the frequency providing the same PTM configuration with respect to the multicast service(s) the UE is receiving as the highest priority,

[0412] - the UE considers the uncongested frequency as the highest priority, or

[0413] - When the MBS multicast service(s) of interest to the UE are no longer available, in particular after a session ends, or when the UE is no longer interested in receiving the multicast service(s), the UE no longer prioritizes the frequencies providing these multicast service(s).

[0414] In one embodiment, the neighbor cell information shows that the PTM configuration in the last serving cell and the reselected cell is the same, and / or the UE receives the multicast using the PTM configuration acquired from the last serving cell after cell reselection.

[0415] In one embodiment, the neighbor cell information shows that the PTM configuration in the reselected cell is delivered by MCCH, and / or the UE monitors MCCH after cell reselection to obtain the PTM configuration and its update.

[0416] In one embodiment, the neighbor cell information shows no congestion and / or MBS service transmission is not supported in RRC_INAVTIVE, and / or PTM configuration is not delivered by MCCH in the reselected cell, and / or the UE triggers the RRC recovery procedure after cell reselection.

[0417] In one embodiment, when there is no information about the reselected cell, the method further includes:

[0418] - The UE monitors the MCCH for PTM configuration, and if PTM cannot be acquired, the UE triggers the RRC recovery procedure, or

[0419] - The UE triggers the RRC recovery procedure to obtain the PTM configuration.

[0420] In one embodiment, the multicast of the UE in the RRC_INACTIVE state further includes at least one of the following:

[0421] -resumeCause is used for multicast configuration update request, which is carried in the RRC resume request,

[0422] -resumeCause is used for multicast service request, which is carried in the RRC resume request,

[0423] - Add a new access category for multicast configuration update / multicast service request requests, the new access category has a higher priority and the related barring factors are specifically configured to always allow access,

[0424] - always skip the bar check process and access directly, especially by reusing access categories, or

[0425] -Skip the Unified Access Control (UAC) process and access directly.

[0426] Although various embodiments of the present disclosure have been described above, it should be understood that they are presented by way of example only, and not by way of limitation. Similarly, various figures may depict exemplary architectures or configurations, which are provided to enable those of ordinary skill in the art to understand the exemplary features and functions of the present disclosure. However, these persons will understand that the present disclosure is not limited to the example architectures or configurations shown, but may be implemented using various alternative architectures and configurations. In addition, as will be appreciated by those of ordinary skill in the art, one or more features of an embodiment may be combined with one or more features of another embodiment described herein. Therefore, the breadth and scope of the present disclosure should not be limited by any of the above-described exemplary embodiments.

[0427] It should also be understood that any reference to an element using the names "first", "second", etc. herein generally does not limit the number or order of these elements. Instead, these names can be used as a convenient means of distinguishing two or more elements or element instances in this article. Therefore, the reference to the first element and the second element does not mean that only two elements can be used or that the first element must be in some way before the second element.

[0428] In addition, those skilled in the art will understand that information and signals may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, and symbols such as may be referenced in the above description may be represented by voltage, current, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

[0429] Those skilled in the art will further understand that any of the various illustrative logical blocks, units, processors, components, circuits, methods, and functions described in conjunction with the various aspects disclosed herein may be implemented by electronic hardware (e.g., digital implementation, analog implementation, or a combination of the two), firmware, various forms of programs or design codes including instructions (for convenience, may be referred to herein as "software" or "software units"), or any combination of these technologies.

[0430] In order to clearly illustrate this interchangeability of hardware, firmware and software, the functions of various illustrative components, blocks, units, circuits and steps have been generally described above. Whether such functions are implemented as hardware, firmware or software, or a combination of these technologies depends on the specific application and the design constraints imposed on the entire system. Those skilled in the art can implement the described functions in various ways for each specific application, but such implementation decisions do not lead to deviations from the scope of this disclosure. According to various embodiments, processors, devices, components, circuits, structures, machines, units, etc. can be configured to perform one or more functions of the functions described herein. The terms "configured to" or "configured for" used herein with respect to a specified operation or function refer to a processor, device, component, circuit, structure, machine, unit, etc. that is physically constructed, programmed and / or arranged to perform a specified operation or function.

[0431] In addition, it will be understood by those skilled in the art that the various illustrative logic blocks, units, devices, components and circuits described herein may be implemented or performed within an integrated circuit (IC), which may include a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, or any combination thereof. The logic blocks, units and circuits may also include antennas and / or transceivers to communicate with various components within a network or within a device. The general-purpose processor may be a microprocessor, but in an alternative, the processor may be any conventional processor, controller or state machine. The processor may also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors combined with a DSP core, or any other suitable configuration for performing the functions described herein. If implemented in software, the functions may be stored as one or more instructions or codes on a computer-readable medium. Therefore, the steps of the method or algorithm disclosed herein may be implemented as software stored on a computer-readable medium.

[0432] Computer-readable media include both computer storage media and communication media, and communication media include any media that can transfer a computer program or code from one place to another. Storage media can be any available media that a computer can access. As an example and not limitation, such computer-readable media can include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, disk storage or other magnetic storage devices, or any other media that can be used to store desired program codes in the form of instructions or data structures and can be accessed by a computer.

[0433] In this document, the term "unit" as used herein refers to software, firmware, hardware, and any combination of these elements for performing the relevant functions described herein. In addition, for the purpose of discussion, various units are described as discrete units; however, as is clear to one of ordinary skill in the art, two or more units may be combined to form a single unit that performs the associated functions according to embodiments of the present disclosure.

[0434] In addition, memory or other storage devices and communication components can be used in embodiments of the present disclosure. It should be understood that, for the sake of clarity, the above description has described embodiments of the present disclosure with reference to different functional units and processors. However, it is clear that any appropriate functional distribution between different functional units, processing logic elements or domains can be used without departing from the present disclosure. For example, the functions shown as being performed by a separate processing logic element or controller can be performed by the same processing logic element or controller. Therefore, reference to a specific functional unit is only a reference to an appropriate means for providing the function, rather than an indication of a strict logical or physical structure or organization.

[0435] Various modifications to the implementations described in this disclosure will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other implementations without departing from the scope of the claims. Therefore, the present disclosure is not intended to be limited to the implementations shown herein, but should be consistent with the widest scope consistent with the novel features and principles disclosed herein, as described in the following claims.

Claims

1. A method for supporting multicast reception of a user equipment UE in an RRC_INACTIVE state, comprising: The distributed unit DU receives the indication information from the central unit CU, and The DU provides configuration information to the CU.

2. The method according to claim 1, The indication information from the CU to the DU is carried in a multicast context establishment request and / or a multicast context modification request. 3 . The method according to claim 1 , wherein the indication information from the CU to the DU is carried in a broadcast context establishment request and / or a broadcast context modification request.

4. The method according to any one of the preceding claims, The configuration information from the DU to the CU is carried in a multicast context establishment response and / or a multicast context modification response.

5. The method according to any one of claims 1 to 3, wherein the configuration information from the DU to the CU is carried in a broadcast context establishment response and / or a broadcast context modification response.

6. The method according to any one of the preceding claims, wherein the indication information from the CU to the DU indicates that (multiple) multicast services are sent for the RRC_INACTIVE UE, and / or The DU maintains point-to-multipoint PTM transmission available for (multiple) multicast services regardless of whether there is a UE in the RRC_CONNECTED state.

7. The method according to claim 6, wherein the indication information from the CU to the DU indicates that the DU is configured with a second set of PTM configurations for the multicast service(s) to be provided via a multicast and broadcast service MBS control channel MCCH, and / or The DU configures and provides the second set of PTM configurations for the multicast service(s) to be provided via the MCCH.

8. The method according to claim 7, wherein the indication information from the CU to the DU indicates that two groups of PTM configurations for the same multicast service have the same resources, and / or wherein the DU configures and provides the PTM configuration through the MCCH based on a current PTM configuration, wherein the current PTM configuration is provided by dedicated signaling for the same multicast service(s); and / or The CU indicates that the resources of two groups of PTM configurations for the same multicast are the same, and the CU provides a mapping relationship between a radio bearer RB index in the MCCH and an RB ID in the dedicated signaling for the same multicast through dedicated signaling.

9. The method according to claim 7, wherein the configuration information from the DU to the CU indicates that the resources of the two groups of PTM configurations for the same multicast service are the same, and / or The CU indicates that the resources of two groups of PTM configurations used for the same multicast are the same, and the CU provides a mapping relationship between an RB index in the MCCH and an RB ID in a dedicated signaling used for the same multicast through dedicated signaling.

10. The method according to any one of the preceding claims, The indication information from the CU to the DU indicates that: regarding the multicast reception area setting of the (multiple) multicast services sent for the RRC_INACTIVE UE, in particular, a notification area RNA area based on a radio access network RAN ​​can be set as a multicast reception area, and / or The DU provides the PTM configuration for the multicast service(s) to all cells in the multicast reception area.

11. The method according to claim 10, wherein the information of the multicast reception area comprises at least one of the following: Cell id list, Cell frequency list, multicast service id, or Whether the PTM configurations are the same.

12. The method according to any one of the preceding claims, wherein the indication information from the CU to the DU indicates a request for cell information related to multicast reception for the RRC_INACTIVE UE, and / or The DU provides the CU with cell information related to multicast reception.

13. The method according to claim 12, The indication information from the CU to the DU carries the collected cell information related to multicast reception to the DU.

14. The method according to claim 13, The cell information includes at least one of the following: Cell ID, Cell frequency, The multicast service ID sent in this cell, The PTM configuration for multicast sent in this cell, whether to support sending multicast to the UE in the RRC_INACTIVE state, Whether the PTM configuration for multicast is delivered via MCCH, or Whether the cell is congested.

15. A network node supporting multicast reception of a user equipment (UE) in an RRC_INACTIVE state, the network node comprising a processor, the processor being configured to: receiving an indication message from a central unit CU, and Configuration information is provided to the CU.

16. The network node according to claim 15, The indication information from the CU to the network node is carried in a multicast context establishment request and / or a multicast context modification request.

17. The network node according to claim 15, wherein the indication information from the CU to the network node is carried in a broadcast context establishment request and / or a broadcast context modification request.

18. The network node according to any one of claims 15 to 17, The configuration information from the network node to the CU is carried in a multicast context establishment response and / or a multicast context modification response.

19. The network node according to any one of claims 15 to 17, The configuration information from the network node to the CU is carried in a broadcast context establishment response or a broadcast context modification response.

20. The network node according to any one of claims 15 to 19, wherein the indication information from the CU to the network node indicates that (multiple) multicast services are sent for the RRC_INACTIVE UE, and / or The processor of the network node is configured to maintain point-to-multipoint PTM transmission available for (multiple) multicast services regardless of whether there is a UE in RRC_CONNECTED state.

21. The network node according to claim 20, wherein the indication information from the CU to the network node indicates that the processor of the network node is configured to configure a second set of PTM configurations for the (multiple) multicast services to be provided via a multicast and broadcast service MBS control channel MCCH, and / or The processor of the network node is configured to configure and provide the second set of PTM configurations for the multicast service(s) to be provided over the MCCH.

22. The network node according to claim 21, wherein the indication information from the CU to the network node indicates that the resources of two groups of PTM configurations for the same multicast service are the same, and / or wherein the processor of the network node is configured to: configure and provide a PTM configuration via the MCCH based on a current PTM configuration, the current PTM configuration being provided via dedicated signaling for the same multicast service(s); and / or The CU is configured to indicate that the resources of two groups of PTM configurations for the same multicast are the same, and a mapping relationship between an RB index in the MCCH and an RB ID in a dedicated signaling for the same multicast is provided through dedicated signaling.

23. The network node according to claim 21 or 22, The configuration information from the network node to the CU indicates that the resources of the two groups of PTM configurations for the same multicast service are the same, and / or The CU is configured to indicate that the resources of two groups of PTM configurations for the same multicast are the same, and a mapping relationship between a radio bearer RB index in the MCCH and an RB ID in dedicated signaling for the same multicast is provided through dedicated signaling.

24. The network node according to any one of claims 15 to 23, The indication information from the CU to the network node indicates that: regarding the multicast reception area setting of the (multiple) multicast services sent for the RRC_INACTIVE UE, in particular, the RAN-based notification area RNA area can be set as a multicast reception area, and / or The processor of the network node is configured to provide the PTM configuration for the multicast service(s) to all cells in the multicast reception area.

25. The network node according to claim 24, wherein the information of the multicast reception area comprises at least one of the following: Cell id list, Cell frequency list, multicast service id, or Whether the PTM configurations are the same.

26. The network node according to any one of claims 15 to 25, wherein the indication information from the CU to the network node indicates a request for cell information related to multicast reception for the RRC_INACTIVE UE, and / or The processor of the network node is configured to provide cell information related to multicast reception to the CU.

27. The network node according to claim 26, The indication information from the CU to the network node carries the collected cell information related to multicast reception to the network node.

28. The network node according to claim 27, The cell information includes at least one of the following: Cell ID, Cell frequency, The multicast service ID sent in this cell, The PTM configuration for multicast sent in this cell, whether to support sending multicast to the UE in the RRC_INACTIVE state, Whether the PTM configuration for multicast is delivered via MCCH, or Whether the cell is congested.

29. A method for supporting multicast reception of a user equipment UE in an RRC_INACTIVE state, the method comprising: receiving, by the UE, configuration for multicast reception in said RRC_INACTIVE state, and Multicast is received by the UE in the RRC_INACTIVE state.

30. The method according to claim 29, The configuration is carried in a radio resource control RRC reconfiguration, and / or an RRC release, and / or a multicast and broadcast service MBS control channel MCCH.

31. The method according to claim 29 or 30, The configuration includes indication information, and the indication information indicates that: the point-to-multipoint PTM configuration is provided through a multicast and broadcast service MBS control channel MCCH for multicast sent in the RRC_INACTIVE state.

32. The method according to claim 31, wherein the configuration indicates that the resources of the two PTM configurations for the same multicast are the same, and carries a mapping relationship between an RB index in the MCCH and an RB ID in a dedicated signaling for the same multicast, and / or The UE modifies the MRB ID according to the mapping relationship, and / or The UE utilizes the modified MRB to receive the multicast.

33. The method according to any one of claims 29 to 32, The configuration carries a list of neighboring cell information related to the multicast reception in the RRC_INACTIVE state.

34. The method according to claim 33, The neighboring cell information includes at least one of the following: Cell ID, The cell frequencies that are providing MBS multicast services, especially the cell-defined SSB CD-SSB, Whether to support sending multicast to UE in the RRC_INACTIVE state, whether to deliver the PTM configuration for multicast via MCCH, Whether the PTM configuration for the same multicast is the same as the current cell, or Whether the cell is congested.

35. The method according to claim 33 or 44, The UE applies a normal cell reselection rule with at least one of the following modifications: - while camping on a frequency providing MBS service(s), the UE which is receiving or interested in receiving these MBS service(s) is allowed to give the highest priority to this frequency, - the UE considers as highest priority the frequency that provides the same PTM configuration with respect to the multicast service(s) that the UE is receiving, - the UE considers uncongested frequencies as the highest priority, or - When the MBS multicast service(s) of interest to the UE are no longer available, in particular after a session ends, or when the UE is no longer interested in receiving the multicast service(s), the UE no longer prioritizes the frequencies providing these multicast service(s).

36. The method according to any one of claims 33 to 35, wherein the neighboring cell information shows that the PTM configuration in the last serving cell and the reselected cell is the same, and / or The UE receives multicast using the PTM configuration acquired from the last serving cell after cell reselection.

37. The method according to any one of claims 33 to 36, wherein the neighboring cell information shows that the PTM configuration in the reselected cell is delivered via MCCH, and / or The UE monitors the MCCH after cell reselection to obtain the PTM configuration and its update.

38. The method according to any one of claims 33 to 37, wherein the neighboring cell information shows no congestion, and / or MBS service transmission is not supported in RRC_INAVTIVE, and / or PTM configuration is not delivered via MCCH in the reselected cell, and / or The UE triggers an RRC recovery process after cell reselection.

39. The method according to any one of claims 29 to 38, wherein when there is no information about the reselected cell, the method further comprises: - the UE monitors the MCCH to obtain the PTM configuration, and if the PTM configuration cannot be obtained, the UE triggers the RRC recovery procedure, or - The UE triggers the RRC recovery procedure to obtain the PTM configuration.

40. The method according to any one of claims 29 to 39, The multicast for UE in RRC_INACTIVE state also includes at least one of the following: -resumeCause is used for requesting multicast configuration update, and the resumeCause is carried in the RRC resume request, -resumeCause is used for multicast service request, and the resumeCause is carried in the RRC resume request, - A new access class is added for multicast configuration update / multicast service request requests, the new access class has a higher priority and the related barring factors are specifically configured to always allow access, - always skip the barring check process and access directly, especially by reusing access categories, or -Skip the Unified Access Control (UAC) process and access directly.

41. A user equipment UE supports multicast reception in an RRC_INACTIVE state, the UE comprising a processor, the processor being configured to: receiving a configuration for multicast reception in said RRC_INACTIVE state, and Multicast is received in the RRC_INACTIVE state.

42. The UE according to claim 41, The configuration is carried in a radio resource control RRC reconfiguration, and / or an RRC release, and / or an MBS control channel MCCH.

43. The UE according to claim 41 or 42, The configuration includes indication information, and the indication information indicates that: the point-to-multipoint PTM configuration is provided through the MBS control channel MCCH for multicast sent in the RRC_INACTIVE state.

44. The UE according to any one of claims 41 to 43, wherein the configuration indicates that the resources of the two PTM configurations for the same multicast are the same, and carries a mapping relationship between a radio bearer RB index in the MCCH and an RB ID in a dedicated signaling for the same multicast, and / or The processor of the UE is configured to: modify the MRBID according to the mapping relationship, and / or The processor of the UE is configured to receive a multicast using a modified MRB.

45. The UE according to any one of claims 41 to 44, The configuration carries a list of neighboring cell information related to the multicast reception in the RRC_INACTIVE state.

46. ​​The UE according to claim 45, The neighboring cell information includes at least one of the following: Cell ID, The cell frequencies that are providing MBS multicast services, especially the cell-defined SSB CD-SSB, Whether to support sending multicast to UE in the RRC_INACTIVE state, whether to deliver the PTM configuration for multicast via MCCH, Whether the PTM configuration for the same multicast is the same as the current cell, or Whether the cell is congested.

47. The UE according to any one of claims 41 to 46, The processor of the UE is configured to apply a normal cell reselection rule with at least one of the following modifications: - while camping on a frequency providing MBS service(s), the processor of the UE receiving or interested in receiving these MBS service(s) is configured to be allowed to give the frequency the highest priority, - the processor of the UE is configured to consider as highest priority a frequency providing the same PTM configuration with respect to the multicast service(s) being received by the UE, - the processor of the UE is configured to consider uncongested frequencies as the highest priority, or -When the MBS multicast service(s) of interest to the UE are no longer available, in particular after a session ends, or when the UE is no longer interested in receiving the multicast service(s), the processor of the UE is configured to no longer prioritize the frequencies providing these multicast service(s).

48. The UE according to any one of claims 45 to 47, wherein the neighbor cell information shows that the PTM configuration in the last serving cell and the reselected cell is the same, and / or The processor of the UE is configured to receive multicast using the PTM configuration acquired from the last serving cell after cell reselection.

49. The UE according to any one of claims 45 to 48, wherein the neighbor cell information shows that the PTM configuration in the reselected cell is delivered via MCCH, and / or The processor of the UE is configured to: monitor the MCCH after cell reselection to obtain PTM configuration and update thereof.

50. The UE according to any one of claims 45 to 49, wherein the neighboring cell information shows no congestion, and / or MBS service transmission is not supported in the RRC_INACTIVE state, and / or PTM configuration is not delivered via MCCH in the reselected cell, and / or The processor of the UE is configured to trigger an RRC recovery process after cell reselection.

51. The UE according to any one of claims 41 to 50, wherein when there is no information about the reselected cell, the processor of the UE is configured to: - monitor the MCCH to obtain the PTM configuration, and if the PTM configuration cannot be obtained, trigger the RRC recovery procedure, or - Trigger the RRC recovery procedure to obtain the PTM configuration.

52. The UE according to any one of claims 41 to 51, The multicast for the UE in the RRC_INACTIVE state further includes at least one of the following: -resumeCause is used for requesting multicast configuration update, and the resumeCause is carried in the RRC resume request, -resumeCause is used for multicast service request, and the resumeCause is carried in the RRC resume request, - A new access class is added for multicast configuration update / multicast service request requests, the new access class has a higher priority and the related barring factors are specifically configured to always allow access, - always skip the barring check process and access directly, especially by reusing access categories, or -Skip the Unified Access Control (UAC) process and access directly.

53. A computer program product comprising computer readable program medium code stored thereon, which, when executed by a processor, causes the processor to implement the wireless communication method according to any one of claims 1 to 14 or 29 to 40.

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