WO2022194272A1

WO2022194272A1 - User equipment and method for mbs service management

Info

Publication number: WO2022194272A1
Application number: PCT/CN2022/081630
Authority: WO
Inventors: Yunglan TSENG; Hengli CHIN; Hungchen CHEN
Original assignee: FG Innovation Company Limited
Priority date: 2021-03-18
Filing date: 2022-03-18
Publication date: 2022-09-22

Abstract

A user equipment (UE) and a method for Multicast Broadcast Service (MBS) service management are provided. The method includes receiving a first radio bearer configuration from a first cell; configuring a first Multicast Radio Bearer (MRB) and an associated first MBS session for a first MBS according to the first radio bearer configuration, the first MBS session having a first MBS session identifier (ID); receiving a full configuration indicator associated with a second radio bearer configuration from the first cell, the second radio bearer configuration including at least one of an MRB configuration or a Data Radio Bearer (DRB) configuration; performing a full configuration procedure according to the full configuration indicator; and determining whether to maintain or release the first MBS session ID and the associated first MBS session based on a service type of the first MBS and the second radio bearer configuration.

Description

USER EQUIPMENT AND METHOD FOR MBS SERVICE MANAGEMENT

FIELD

The present disclosure is related to wireless communication, and more particularly, to a user equipment (UE) and a method for Multicast Broadcast Service (MBS) service management in cellular wireless communication networks.

BACKGROUND

The acronyms in the present application are defined as follows and unless otherwise specified, the acronyms have the following meanings:

Abbreviation Full name

3GPP 3 ^rd Generation Partnership Project

5G 5 ^th Generation

5GC 5G Core

ACK Acknowledgement

AS Access Stratum

BS Base Station

BWP Bandwidth Part

CA Carrier Aggregation

CAG Closed Access Group

CN Core Network

CSI-RS Channel State Information Reference Signal

CU Central Unit

DAPS Dual Active Protocol Stack

DC Dual Connectivity

DCI Downlink Control Information

DL Downlink

DRB Data Radio Bearer

DU Distributed Unit

E-UTRA (N) Evolved Universal Terrestrial Radio Access (Network)

EN-DC E-UTRA NR Dual Connectivity

EPC Evolved Packet Core

EPS Evolved Packet System

FR Frequency Range

HARQ Hybrid Automatic Repeat reQuest

IAB Integrated Access and Backhaul

ID Identifier/Identity

IE Information Element

LAN Local Area Network

LTE Long Term Evolution

MAC Medium Access Control

MAC CE MAC Control Element

MBS Multicast Broadcast Service

MC Multi-Connectivity

MCG Master Cell Group

MIB Master Information Block

MN Master Node

MR Multi RAT

MRB Multicast Radio Bearer

MSG Message

MT Mobile Termination

NAS Non-Access Stratum

NE-DC NR -E-UTRA Dual Connectivity

NPN Non-Public Network

NR New Radio

NR-U NR Unlicensed

NW Network

PCell Primary Cell

PCI Physical Cell Identity

PDCCH Physical Downlink Control Channel

PDCP Packet Data Convergence Protocol

PDSCH Physical Downlink Shared Channel

PDU Packet Data Unit

PHY Physical (layer)

PLMN Public Land Mobile Network

PNI-NPN Public Network Integrated Non-Public Network

PRACH Physical Random Access Channel

PSCell Primary SCG Cell /Primary Secondary Cell

PUCCH Physical Uplink Control Channel

PUSCH Physical Uplink Shared Channel

QoS Quality of Service

RA Random Access

RAN Radio Access Network

RAR Random Access Response

RAT Radio Access Technology

RF Radio Frequency

RLC Radio Link Control

RNTI Radio Network Temporary Identifier

RRC Radio Resource Control

RS Reference Signal

RSRP Reference Signal Received Power

RSRQ Reference Signal Received Quality

SCell Secondary Cell

SCG Secondary Cell Group

SDAP Service Data Adaptation Protocol

SI System Information

SIB System Information Block

SL Sidelink

SN Secondary Node

SNPN Stand-alond Non-Public Network

SRB Signaling Radio Bearer

SSB Synchronization Signal Block

TMGI Temporary Mobile Group Identity

TS Technical Specification

UE User Equipment

UL Uplink

UMTS Universal Mobile Telecommunications System

USIM UMTS Subscriber Identity Module

V2X Vehicle-to-Everything

With the tremendous growth in the number of connected devices and the rapid increase in user/network traffic volume, various efforts have been made to improve different aspects of wireless communication for the next-generation wireless communication system, such as the fifth-generation (5G) New Radio (NR) , by improving data rate, latency, reliability, and mobility. The 5G NR system is designed to provide flexibility and configurability to optimize the network services and types, accommodating various use cases, such as enhanced Mobile Broadband (eMBB) , massive Machine-Type Communication (mMTC) , and Ultra-Reliable and Low-Latency Communication (URLLC) . However, as the demand for radio access continues to increase, there exists a need for further improvements in the art.

SUMMARY

The present disclosure is related to a method performed by a UE in cellular wireless communication network for MBS service management.

In a first aspect of the present application, a method for MBS service management performed by a UE is provided. The method includes receiving a first radio bearer configuration from a first cell; configuring a first Multicast Radio Bearer (MRB) and an associated first MBS session for a first MBS according to the first radio bearer configuration, the first MBS session having a first MBS session identifier (ID) ; receiving a full configuration indicator associated with a second radio bearer configuration from the first cell, the second radio bearer configuration including at least one of an MRB configuration or a Data Radio Bearer (DRB) configuration; performing a full configuration procedure according to the full configuration indicator; and determining whether to maintain or release the first MBS session ID and the associated first MBS session based on a service type of the first MBS and the second radio bearer configuration.

In an implementation of the first aspect, the first MBS session and the associated first MBS session ID are maintained by the UE in a case that the first MBS session ID is associated with the at least one of the MRB configuration or the DRB configuration in the second radio bearer configuration.

In another implementation of the first aspect, the first MBS session and the associated first MBS session ID is released by the UE in a case that the first MBS session ID is not associated with any one of the at least one of the MRB configuration or the DRB configuration in the second radio bearer configuration.

In another implementation of the first aspect, the first MBS session is maintained by the UE (e.g., during the full configuration procedure) in a case that the service type of the first MBS is a broadcast service and the first MRB is a broadcast MRB.

In another implementation of the first aspect, the full configuration indicator is transmitted via a handover instruction, which is generated by a second cell and is transmitted to the first cell via a backhaul connection between the first cell and the second cell; and the full configuration procedure is performed after the UE receives the handover instruction to handover to the second cell.

In another implementation of the first aspect, each of the first cell and the second cell is one of an E-UTRA cell and an NR cell.

In another implementation of the first aspect, the full configuration indicator is transmitted via a conditional handover instruction, which is generated by a third cell and is transmitted to the first cell via a backhaul connection between the first cell and the third cell; and the full configuration procedure is performed after the UE determines to handover to the third cell based on the conditional handover instruction.

In another implementation of the first aspect, each of the first cell and the third cell is one of an E-UTRA cell and an NR cell.

In another implementation of the first aspect, the first MBS session is released by the UE (e.g., during the full configuration procedure) in a case that the service type of the first MBS is a multicast service and the first MRB is a multicast MRB.

In another implementation of the first aspect, the full configuration indicator is received by the UE via one of a Signaling Radio Bearer 1 (SRB1) and a Signaling Radio Bearer 3 (SRB3) while the UE is configured with multi-connectivity (MC) functionality to communicate with one or more serving base stations simultaneously; the SRB1 is constructed between the UE and a primary cell; and the SRB3 is constructed between the UE and a primary secondary cell.

In a second aspect, a UE for MBS service management is provided. The UE includes one or more processors and at least one memory coupled to at least one of the one or more processors, where the at least one memory stores a computer-executable program that, when executed by the at least one of the one or more processors, causes the UE to receive a first radio bearer configuration from a first cell; configuring a first MRB and an associated first MBS session for a first MBS according to the first radio bearer configuration, the first MBS session having a first MBS session ID; receiving a full configuration indicator associated with a second radio bearer configuration from the first cell, the second radio bearer configuration including at least one of an MRB configuration or a DRB configuration; performing a full configuration procedure according to the full configuration indicator; and determining whether to maintain or release the first MBS session ID and the associated first MBS session based on a service type of the first MBS and the second radio bearer configuration.

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects of the present disclosure are best understood from the following detailed description when read with the accompanying drawings. Various features are not drawn to scale. Dimensions of various features may be arbitrarily increased or reduced for clarity of discussion.

FIG. 1 illustrates an MBS traffic delivery architecture according to an implementation of the present disclosure.

FIG. 2 illustrates a process of full configuration according to an implementation of the present disclosure.

FIG. 3 illustrates a process of MBSInterestIndication transmission according to an implementation of the present disclosure.

FIG. 4 illustrates a method performed by a UE for MBS service management according to an implementation of the present disclosure. FIG.

FIG. 5 is a block diagram illustrating a node for wireless communication according to an implementation of the present disclosure.

DESCRIPTION

The following description contains specific information related to implementations of the present disclosure. The drawings and their accompanying detailed description are merely directed to implementations. However, the present disclosure is not limited to these implementations. Other variations and implementations of the present disclosure will be obvious to those skilled in the art.

Unless noted otherwise, like or corresponding elements among the drawings may be indicated by like or corresponding reference numerals. Moreover, the drawings and illustrations in the present disclosure are generally not to scale and are not intended to correspond to actual relative dimensions.

For the purpose of consistency and ease of understanding, like features may be identified (although, in some examples, not illustrated) by the same numerals in the drawings. However, the features in different implementations may be differed in other respects and shall not be narrowly confined to what is illustrated in the drawings.

The phrases “in one implementation, ” or “in some implementations, ” may each refer to one or more of the same or different implementations. The term “coupled” is defined as connected whether directly or indirectly through intervening components and is not necessarily limited to physical connections. The term “comprising” means “including, but not necessarily limited to” and specifically indicates open-ended inclusion or membership in the so-described combination, group, series or equivalent. The expression “at least one of A, B and C” or “at least one of the following: A, B and C” means “only A, or only B, or only C, or any combination of A, B and C. ”

The terms “system” and “network” may be used interchangeably. The term “and/or” is only an association relationship for describing associated objects and represents that three relationships may exist such that A and/or B may indicate that A exists alone, A and B exist at the same time, or B exists alone. The character “/” generally represents that the associated objects are in an “or” relationship.

For the purposes of explanation and non-limitation, specific details such as functional entities, techniques, protocols, and standards are set forth for providing an understanding of the disclosed technology. In other examples, detailed description of well-known methods, technologies, systems, and architectures are omitted so as not to obscure the description with unnecessary details.

Persons skilled in the art will immediately recognize that any network function (s) or algorithm (s) disclosed may be implemented by hardware, software or a combination of software and hardware. Disclosed functions may correspond to modules which may be software, hardware, firmware, or any combination thereof.

A software implementation may include computer executable instructions stored on a computer readable medium such as memory or other type of storage devices. One or more microprocessors or general-purpose computers with communication processing capability may be programmed with corresponding executable instructions and perform the disclosed network function (s) or algorithm (s) .

The microprocessors or general-purpose computers may include Applications Specific Integrated Circuitry (ASIC) , programmable logic arrays, and/or using one or more Digital Signal Processor (DSPs) . Although some of the disclosed implementations are oriented to software installed and executing on computer hardware, alternative implementations implemented as firmware or as hardware or combination of hardware and software are well within the scope of the present disclosure. The computer readable medium includes but is not limited to Random Access Memory (RAM) , Read Only Memory (ROM) , Erasable Programmable Read-Only Memory (EPROM) , Electrically Erasable Programmable Read-Only Memory (EEPROM) , flash memory, Compact Disc Read-Only Memory (CD-ROM) , magnetic cassettes, magnetic tape, magnetic disk storage, or any other equivalent medium capable of storing computer-readable instructions.

A radio communication network architecture such as a Long Term Evolution (LTE) system, an LTE-Advanced (LTE-A) system, an LTE-Advanced Pro system, or a 5G NR Radio Access Network (RAN) typically includes at least one BS, at least one UE, and one or more optional network elements that provide connection within a network. The UE communicates with the network such as a Core Network (CN) , an Evolved Packet Core (EPC) network, an Evolved Universal Terrestrial RAN (E-UTRA) , a 5G Core (5GC) , or an internet via a RAN established by one or more BSs.

A UE may include but is not limited to a mobile station, a mobile terminal or device, or a user communication radio terminal. The UE may be portable radio equipment that includes but is not limited to a mobile phone, a tablet, a wearable device, a sensor, a vehicle, or a Personal Digital Assistant (PDA) with wireless communication capability. The UE is configured to receive and transmit signals over an air interface to one or more cells in a RAN.

A BS may be configured to provide communication services according to at least a Radio Access Technology (RAT) such as Worldwide Interoperability for Microwave Access (WiMAX) , Global System for Mobile communications (GSM) that is often referred to as 2G, GSM Enhanced Data rates for GSM Evolution (EDGE) RAN (GERAN) , General Packet Radio Service (GPRS) , Universal Mobile Telecommunication System (UMTS) that is often referred to as 3G based on basic wideband-code division multiple access (W-CDMA) , high-speed packet access (HSPA) , LTE, LTE-A, evolved LTE (eLTE) that is LTE connected to 5GC, NR (often referred to as 5G) , and/or LTE-A Pro. However, the scope of the present disclosure is not limited to these protocols.

A BS may include but is not limited to a node B (NB) in the UMTS, an evolved node B (eNB) in LTE or LTE-A, a radio network controller (RNC) in UMTS, a BS controller (BSC) in the GSM/GERAN, a ng-eNB in an E-UTRA BS in connection with 5GC, a next generation Node B (gNB) in the 5G-RAN, or any other apparatus capable of controlling radio communication and managing radio resources within a cell. The BS may serve one or more UEs via one or more radio interface.

The BS is operable to provide radio coverage to a specific geographical area using a plurality of cells forming the RAN. The BS supports the operations of the cells. Each cell is operable to provide services to at least one UE within its radio coverage.

Each cell (often referred to as a serving cell) provides services to serve one or more UEs within its radio coverage such that each cell schedules the downlink (DL) and optionally uplink (UL) resources to at least one UE within its radio coverage for DL and optionally UL packet transmissions. The BS can communicate with one or more UEs in the radio communication system via the plurality of cells.

A cell may allocate sidelink (SL) resources for supporting Proximity Service (ProSe) (e.g., (ProSe) direct communication services and (ProSe) direct discovery services) or V2X services (e.g., E-UTRA V2X sidelink communication services) or sidelink service (e.g., NR sidelink communication services) . Each cell may have overlapped coverage areas with other cells.

As discussed previously, the frame structure for NR supports flexible configurations for accommodating various next generation (e.g., 5G) communication requirements such as Enhanced Mobile Broadband (eMBB) , Massive Machine Type Communication (mMTC) , and Ultra-Reliable and Low-Latency Communication (URLLC) , while fulfilling high reliability, high data rate and low latency requirements. The Orthogonal Frequency-Division Multiplexing (OFDM) technology in the 3rd Generation Partnership Project (3GPP) may serve as a baseline for an NR waveform. The scalable OFDM numerology such as adaptive sub-carrier spacing, channel bandwidth, and Cyclic Prefix (CP) may also be used.

Two coding schemes are considered for NR, specifically Low-Density Parity-Check (LDPC) code and Polar Code. The coding scheme adaption may be configured based on channel conditions and/or service applications.

At least DL transmission data, a guard period, and UL transmission data should be included in a transmission time interval (TTI) of a single NR frame. The respective portions of the DL transmission data, the guard period, and the UL transmission data should also be configurable based on, for example, the network dynamics of NR. Sidelink resources may also be provided in an NR frame to support ProSe services, V2X services (e.g., E-UTRA V2X sidelink communication services) or sidelink services (e.g., NR sidelink communication services) . In contrast, sidelink resources may also be provided in an E-UTRA frame to support ProSe services, V2X services (e.g., E-UTRA V2X sidelink communication services) or sidelink services (e.g., NR sidelink communication services) .

Examples of some selected terms are provided as follows.

Network (NW) , Radio Access Network (RAN) , cell, camped cell, serving cell, base station, gNB, eNB and ng-eNB may be used interchangeably in the present disclosure. In some implementations, some of these terms may refer to the same network entity.

Serving Cell: For a UE in RRC_CONNECTED not configured with CA/DC there is only one serving cell comprising of the primary cell. For a UE in RRC_CONNECTED configured with CA/DC the term ‘serving cells’ is used to denote the set of cells comprising of the Special Cell (s) and all secondary cells.

Special Cell: For Dual Connectivity operation the term Special Cell refers to the PCell of the MCG or the PSCell of the SCG, otherwise the term Special Cell refers to the PCell.

The disclosed implementations may be applied to any RAT. The RAT may be (but not limited to) NR, NR-U, LTE, E-UTRA connected to 5GC, LTE connected to 5GC, E-UTRA connected to EPC, and LTE connected to EPC. The disclosed implementations may be applied to UEs in public networks, or in private network (e.g., NPN such as SNPN and PNI-NPN) .

The disclosed implementations may be used for licensed frequency and/or unlicensed frequency.

System information (SI) may refer to MIB, SIB1, and other SI. Minimum SI may include MIB and SIB1. Other SI may refer to SIB3, SIB4, SIB5, and other SIB (s) (e.g., SNPN-specific SIB, PNI-NPN-specific SIB) .

Dedicated signaling may refer to (but not limited to) RRC message (s) . For example, RRC (Connection) Setup Request message, RRC (Connection) Setup message, RRC (Connection) Setup Complete message, RRC (Connection) Reconfiguration message, RRC Connection Reconfiguration message including the mobility control information, RRC Connection Reconfiguration message without the mobility control information inside, RRC Reconfiguration message including the configuration with sync, RRC Reconfiguration message without the configuration with sync inside, RRC (Connection) Reconfiguration complete message, RRC (Connection) Resume Request message, RRC (Connection) Resume message, RRC (Connection) Resume Complete message, RRC (Connection) Reestablishment Request message, RRC (Connection) Reestablishment message, RRC (Connection) Reestablishment Complete message, RRC (Connection) Reject message, RRC (Connection) Release message, RRC System Information Request message, UE Assistance Information message, UE Capability Enquiry message, and UE Capability Information message. RRC message may be one type of dedicated signaling. The UE may receive the RRC message from the network via unicast/broadcast/groupcast.

The RRC_CONNECTED UE, RRC_INACTIVE UE, and RRC_IDLE UE may apply the disclosed implementations.

An RRC_CONNECTED UE may be configured with an active BWP with common search space configured to monitor system information or paging.

The disclosed implementations may be applied to the PCell and the UE. In some implementations, the disclosed implementations may be applied to the PSCell and the UE. The disclosed short message and/or paging DCI may be transmitted by the PSCell (or secondary node) to the UE. The UE may monitor the PDCCH monitoring occasions for paging configured by the PSCell (or secondary node) .

Allowed CAG list: a per-PLMN list of CAG Identifiers the UE is allowed to access.

CAG cell: A cell broadcasting at least one CAG Identifier.

CAG Member Cell: for a UE, a cell broadcasting the identity of the selected PLMN, registered PLMN or equivalent PLMN, and for that PLMN, a CAG identifier belonging to the Allowed CAG list of the UE for that PLMN.

CAG Identifier: CAG Identifier identifies a CAG within a PLMN.

Network Identifier: Network Identifier identifies an SNPN in combination with a PLMN ID.

Non-Public Network: A network deployed for non-public use.

NPN-only Cell: A cell that is only available for normal service for NPNs’ subscriber. An NPN-capable UE determines that a cell is NPN-only Cell by detecting that the cellReservedForOtherUse IE is set to true while the npn-IdentityInfoList IE is present in CellAccessRelatedInfo IE.

PNI-NPN identity: an identifier of a PNI-NPN comprising of a PLMN ID and a CAG -ID combination.

Registered SNPN: This is the SNPN on which certain Location Registration outcomes have occurred.

Selected SNPN: This is the SNPN that has been selected by the NAS (e.g., the NAS of the UE, the NAS of the CN) , either manually or automatically.

SNPN Access Mode: mode of operation in which the UE only selects SNPNs.

SNPN identity: an identifier of an SNPN comprising of a PLMN ID and an NID combination.

SNPN-only cell: a cell that is only available for normal service for SNPN subscribers.

An NPN-capable UE may correspond to a UE supporting CAG (or NPN) .

Child node: IAB-node-DU’s next hop neighbour node; the child node is also an IAB-node.

Parent node: IAB-node-MT’s next hop neighbour node; the parent node can be IAB-node or IAB-donor-DU.

Downstream: Direction toward child node or UE in IAB-topology.

Upstream: Direction toward parent node in IAB-topology.

IAB-donor: gNB that provides network access to UEs via a network of backhaul and access links.

IAB-DU: gNB-DU functionality supported by the IAB-node to terminate the NR access interface to UEs and next-hop IAB-nodes, and to terminate the F1 protocol to the gNB-CU functionality, as defined in 3GPP TS 38.401, on the IAB-donor.

IAB-MT: IAB-node function that terminates the Uu interface to the parent node using the procedures and behaviours specified for UEs unless stated otherwise. IAB-MT function used in 38series of 3GPP Specifications corresponds to IAB-UE function defined in 3GPP TS 23.501.

IAB-node: RAN node that supports NR access links to UEs and NR backhaul links to parent nodes and child nodes. The IAB-node may or may not support backhauling via LTE.

Multi-hop backhauling: Using a chain of NR (and/or LTE) backhaul links between an IAB-node and an IAB-donor-gNB.

NR backhaul link: NR link used for backhauling between an IAB-node and an IAB-donor-gNB, and between IAB-nodes in case of a multi-hop backhauling.

LTE backhaul link: LTE link used for backhauling between an IAB-node and an IAB-donor-gNB, and between IAB-nodes in case of a multi-hop backhauling.

Multi-Radio Dual Connectivity (MR-DC) : Dual Connectivity between E-UTRA and NR nodes, or between two NR nodes. MR-DC may include E-UTRA-NR Dual Connectivity (EN-DC) , NR-E-UTRA Dual Connectivity (NE-DC) , NG-RAN E-UTRA-NR Dual Connectivity (NGEN-DC) , and NR-NR Dual Connectivity (NR-DC) .

Master Cell Group: in MR-DC, a group of serving cells associated with the Master Node, comprising of the SpCell (PCell) and optionally one or more SCells.

Master node: in MR-DC, the radio access node that provides the control plane connection to the core network. It may be a Master eNB (in EN-DC) , a Master ng-eNB (in NGEN-DC) or a Master gNB (in NR-DC and NE-DC) .

Secondary Cell Group: in MR-DC, a group of serving cells associated with the Secondary Node, comprising of the SpCell (PSCell) and optionally one or more SCells.

Secondary node: in MR-DC, the radio access node, with no control plane connection to the core network, providing additional resources to the UE. It may be an en-gNB (in EN-DC) , a Secondary ng-eNB (in NE-DC) or a Secondary gNB (in NR-DC and NGEN-DC) .

MeNB: Master eNB, an eNB as a master node associated with an MCG (Master Cell Group) in MR-DC scenarios.

SgNB: Secondary gNB, a gNB as a secondary node associated with an SCG (Secondary Cell Group) in MR-DC scenarios.

A first indication may be associated with NR, LTE connected to EPC, and/or LTE connected to 5GC. A second indication may be associated with NR, LTE connected to EPC, and/or LTE connected to 5GC. The first indication and the second indication may be associated with the same RAT (e.g., NR, LTE connected to EPC, LTE connected to 5GC) or different RATs. The UE supporting one RAT (e.g., IAB functionality via NR and/or NPN functionality via NR, if the one RAT is NR) may apply the first indication associated with NR and/or the second indication associated with NR. The UE supporting the one RAT may apply (or ignore) the first indication not associated with NR and/or the second indication not associated with NR.

In some implementations, if the UE considers itself barred by a cell or if the UE bars a cell, the UE may bar the cell for a period of time (e.g., 300s) . The UE may not consider the cell as a candidate cell for cell (re) selectin for a period of time (e.g., 300s) .

In some implementations, if the UE changes from the SNPN access mode to the PLMN access mode, (the NAS entity of) the UE may release (or delete or discard) the (stored or maintained) list of SNPN ID (s) if any.

In some implementations, if the UE changes from the PLMN access mode to the SNPN access mode, (the NAS entity of) the UE may release (or delete or discard) the (stored or maintained) list of PLMN ID (s) if any.

Downlink Control Information (DCI) : DCI may refer to a PDCCH resource with Cyclic Redundancy Check (CRC) scrambled by an Radio Network Temporary Identifier (RNTI) . The RNTI may relate to IAB. Implementations regarding DCI may be applied for a physical signal.

Medium Access Control (MAC) Control Element (CE) : A MAC CE is a bit string that is byte aligned (e.g., multiple of 8 bits) in length.

In some implementations, if the UE with IAB functionality determines itself to be an IAB node or operate as an IAB node, and/or if the UE performs the design for IAB, and/or if the UE operates the IAB functions, the UE may transmit an indication to inform the network via dedicated signaling.

DAPS bearer: a bearer whose radio protocols are located in both the source gNB and the target gNB during DAPS handover to use both source gNB and target gNB resources.

MBS Traffic Delivery

FIG. 1 illustrates an MBS traffic delivery architecture 100 according to an implementation of the present disclosure. MBS traffic may be delivered from a single data source (e.g., one or more Application Service Providers) to one or more UEs. Multiple delivery methods may be used to delivered MBS traffic in the 5G system (5GS) . MBS traffic delivery methods may be referred to 3GPP TS 23.757.

5GC individual MBS delivery method: 5G CN 120 receives a single copy of MBS data packets and then delivers separate copies of those MBS data packets to individual UEs (e.g., UE 106 and UE 108) via per-UE packet data unit (PDU) sessions (or PDU session/pdu-sessions) . Therefore, for each such UE, one PDU session is required to be associated with a multicast session or Multi-media Broadcast/Multicast Service (MBMS) session.

5GC shared MBS traffic delivery method: 5G CN 120 receives a single copy of MBS data packets and delivers a single copy of those MBS packets to 5G RAN 110. Then, the 5G RAN 110 may deliver the packets to one or multiple UEs (e.g., UE 102 and UE 104) . For example, UE 102 may receive a radio bearer configuration from 5G RAN 110, and UE 102 may configure an MRB and an associated MBS session (shared transport 130 in FIG. 1) according to the radio bearer configuration. The MBS session may have an MBS session ID, such as TMGI #1.

A same received single copy of MBS data packets by the 5G CN 120 may be delivered via both 5GC individual MBS traffic delivery method for some UEs (e.g., UE 106 and UE 108) and/or 5GC shared MBS traffic delivery method for other UEs (e.g., UE 102 and UE 104) . In addition, from the viewpoint of 5G RAN 110 (in the case of the shared delivery) , two delivery methods are available for the transmission of MBS packet flows over radio, including Point-to-Point (PTP) delivery method and Point-to-Multipoint (PTM) delivery method.

PTP delivery method: a RAN node or a base station (e.g., NR gNB) delivers separate copies of MBS data packet over radio to individual UE.

PTM delivery method: a RAN node or a base station (e.g., NR gNB) delivers a single copy of MBS data packets over radio to a set of UEs.

A RAN node may use a combination of PTP/PTM to deliver an MBS packet to UEs. In addition, the PTP/PTM delivery method may be applicable to 5GC individual MBS delivery method and/or 5GC shared MBS traffic delivery method. To the 5G RAN, PTP/PTM delivery (with 5GC shared delivery method) and 5GC individual delivery method may be used at the same time for a MBS session/MBMS session/PDU session.

From an AS layer’s point of view, how the 5G RAN supports MBS service and MBS sessions (MBMS sessions) /PDU sessions may influence UE implementations while a full configuration procedure is applied to support MBS. For example, the UE may be configured with Multicast Radio Bearer (s) (MRB (s) ) to be associated with the MBS session (or MBMS session) directly (e.g., the shared transport approach) . In addition, each MRB may be configured with a) PTM-only delivery methods, b) PTP-only delivery methods, c) both PTM &PTP delivery methods. In some implementations, the UE may be configured with one or more PDU session (s) to be associated with one or more target MBS (s) in the upper layers (e.g., SDAP layer or NAS layer) . In addition, in the AS layers, the UE may be configured with MRB (s) and/or DRB (s) to be associated with the active/configured PDU session.

Full Configuration

Full configuration on Uu interface for DRB/SRB/sidelink configuration may be referred to 3GPP TS 36.331/TS 38.331. However, to support Multi-cast and/or Broadcast services in 3GPP protocols (e.g., NR Protocols or E-UTRA protocols) , the full configuration procedure should cover the configurations for MBS. Implementations of the full configuration are disclosed in the present disclosure while the MBS session/PDU session and related associated radio bearer configuration are taken into consideration.

MBSInterestIndication

Implementations regarding an IE MBSInterestIndication are also provided in the present disclosure. A UE may deliver MBSInterestIndication to a serving cell to support Multi-cast/Broadcast services between the serving RAN and the concerned UE.

In some implementations, the serving cell may instruct the UE to re-setup/reset/release/reconfigure the MBS-related configuration (e.g., MBS bearer configuration or radio configurations to support one or more MBSs) by delivering one (or more) MBS full configuration indicator (s) in one or more downlink UE-specific control signaling (e.g., RRC signaling. )

FIG. 2 illustrates a process 200 of full configuration according to an implementation of the present disclosure. Serving cell 204 transmits RRCReconfiguration message 206 with (MBS) full configuration option to UE 202. After UE 202 performs a full configuration procedure according to the full configuration indicator in the RRCReconfiguration message 206, UE 202 transmits RRCReconfigurationComplete message 208 to serving cell 204.

(MBS) Full Configuration Indicator

In some implementations, one explicit MBS full configuration indicator may be delivered by the serving cell to the UE. Moreover, the MBS full configuration indicator may be configured independently with the ‘full configuration indicator’ in the DL RRC signaling.

In this condition (while the MBS full configuration indicator is provided independently with the ‘full configuration indicator’ ) , the UE may only trigger/apply the ‘MBS full configuration’ after receiving the ‘MBS full configuration indicator’ in the DL control signaling. In contrast, the UE may not trigger the ‘MBS full configuration’ if the UE only receives ‘full configuration indicator’ in the DL control signaling.

In some implementations, the existing ‘full configuration indicator’ may also be treated as the MBS full configuration indicator. The UE may apply/trigger the ‘MBS full configuration’ and the existing full configuration implementations (described in 3GPP TS 36.331/TS 38.331) if the UE receives the ‘full configuration indicator’ in the DL control signaling. In some implementations, the MBS full configuration may be part of (or a subset of) the full configuration.

In some implementations, one ‘full configuration indicator’ and/or another ‘MBS full configuration indicator’ may be present in the DL RRC signaling. If ‘full configuration indicator’ is present (or set to true) , the UE may apply/trigger both the existing full configuration implementations (described in 3GPP TS 36.331/TS 38.331) and the ‘MBS full configuration’ . If ‘full configuration indicator’ is not present (or set to false) and if ‘MBS full configuration indicator’ is present (or set to true) , the UE may only apply/trigger the ‘MBS full configuration’ and may not apply/trigger the existing full configuration implementations (in 3GPP TS 36.331/TS 38.331) . In some implementations, if ‘full configuration indicator’ is present (or set to true) in the DL RRC signaling, ‘MBS full configuration indicator’ may not be present in the same DL RRC signaling.

In some implementations, the MBS full configuration indicator may be associated with one (or a subset) of the active Multicast/Broadcast services. In some implementations, the mapping configuration between the MBS full configuration indicator (s) and the target MBS (s) may be pre-configured/pre-specified in the 3GPP specification (e.g., one bitmap may be configured as the MBS full configuration indicator and one bit in the bitmap may be associated one target MBS) . In some implementations, the sequence of the bitmap may be associated with the sequence of supported MBS list (e.g., in an ascending order or in a descending order) , which may be transmitted by the serving cell (or serving RAN) via broadcast system information or UE specific dedicated control signaling. In some implementations, the sequence of the bitmap may be associated with the sequence of the UE’s interested MBS list (e.g., in an ascending order or in a descending order) , which may be transmitted to the serving cell (or serving RAN) via UE specific dedicated control signaling (e.g., a MBSInterestIndication message) . In some implementations, the serving RAN may instruct a UE to perform full configuration to one (or more) target MBS (s) by transmitting the ‘MBS service ID’ (e.g., the service identifier that is pre-defined in technical specification or in NAS layer, pre-installed in USIM, or pre-configured in broadcasting system information) to the concerned UE directly (e.g., via one or more UE-specific DL RRC Signaling) .

In some implementations, if a UE (that connects to 5GC) performs (intra-system/inter-system) inter-RAT handover from a source cell to a target cell and the UE receives a RRCConnectionReconfiguration message that does not include “full configuration indicator” from the target cell, the UE may re-use the source SDAP and PDCP configurations for all RBs (e.g., SRB and/or DRB) except MBS radio bearer (s) /MRB (s) , from the source cell. In some implementations, if a UE (that connects to 5GC) performs (intra-system/inter-system) inter-RAT handover from a source cell to a target cell and the UE receives a RRCConnectionReconfiguration message that does not include “full configuration indicator” from the target cell, the UE may re-use the source SDAP and PDCP configurations for MRB (s) . In some implementations, the source cell may be an NR cell and the target cell may be an E-UTRA cell (or vice versa) . The disclosed mechanism may also be applicable to a conditional handover/conditional re-configuration procedure. In some implementations, the disclosed mechanism is also applicable to Dual Active Protocol Stack (DAPS) handover procedure.

Signaling Design

RRCReconfiguration message: In some implementations, the serving cell may transmit the ‘MBS full configuration indicator’ in the RRCReconfiguration message with reconfigurationwithsync IE (e.g., for the intra-RAT/inter-RAT/inter-system handover procedure or PSCell change event) . In some implementations, the serving cell may transmit the ‘MBS full configuration indicator’ in (LTE/NR) RRCReconfiguration message without attaching the reconfigurationwithsync (or mobilitycontrolinfo) IE.

Conditional Reconfiguration/conditional handover: In some implementations, the serving cell may transmit the ‘MBS full configuration indicator’ in RRCReconfiguration message with the IE ConditionalReconfiguration (e.g., for a conditional handover procedure) . The MBS full configuration indicator may be associated with all or a subset of the candidates (or candidate cells) in the conditional handover event. The UE may trigger MBS full configuration if the UE selects to handover to a candidate cell that is also associated with the given MBS full configuration indicator. Otherwise, the UE may not trigger MBS full configuration if the UE selects to handover to a candidate cell that is not associated with the given MBS full configuration indicator. In some implementations, each (MBS) full configuration indicator may only be associated with one candidate cell in the conditional reconfiguration IE. The UE may receive one bitmap of (MBS) full configuration IE and each bit in the bitmap may represent one (MBS) full configuration indicator to be associated with one (and only one) candidate cell in the conditional handover (or conditional reconfiguration) event. In some implementations, a first value of a bit in the bitmap may be used to indicate that a UE should trigger an MBS full configuration in the cell associated with the bit, and a second value of the bit may be used to indicate that an MBS full configuration should not be triggered for the cell associated with the bit. The sequence of the bitmap may be associated with the sequence of target cell identity list (e.g., in an ascending order or in a descending order) , which may be transmitted by the serving cell (or serving RAN) via one UE specific dedicated control signaling) .

RRCResume message: In some implementations, the serving cell may transmit the ‘MBS full configuration indicator’ in RRCResume message to the UE (e.g., as the response after the UE transmits a RRCResumeRequest message to the serving cell) .

RRCSetup message: In some implementations, the serving cell may transmit the Z ‘MBS full configuration indicator’ in RRCSetup message to the UE (e.g., as the response after the UE transmits a RRCResumeRequest, RRCReestablishmentRequest, or RRCSetupRequest message to the serving cell) .

In some implementations, the serving cell may transmit the ‘ (MBS) full configuration indicator’ in RRCRelease message to the UE (e.g., as the response after the UE transmits a RRCResumeRequest or RRCSetupRequest message to the serving cell) . In addition, the serving cell may transmit a RRCRelease message with suspend configuration (e.g., to instruct the UE to move to (LTE/NR) RRC Inactive state) & (MBS) full configuration indicator to the UE. The UE may implement (MBS) full configuration after moving to (LTE/NR) RRC Inactive state. In addition, new MBS radio configuration may be configured with the (MBS) full configuration indicator. Then, the UE may continue the MBS packet reception based on the new MBS radio configuration after the (MBS) full configuration is implemented.

In some implementations, the serving cell may transmit the ‘MBS full configuration indicator’ through broadcasting DL control signal (e.g., system information, such as MIB, system information block type1 (SIB1) or other SI) to one or more UEs.

Implicit approach: In some implementations, the UE may implement MBS full configuration directly without reception of the MBS full configuration indicator. For example, the UE may implement MBS full configuration directly after the UE moving from NR/E-UTRA RRC Connected state to (NR/E-UTRA) RRC Inactive state or (NR/E-UTRA) RRC Idle state. In some implementations, the UE may implement MBS full configuration directly after the inter-RAT handover procedure (e.g., from NR (source) cell to E-UTRA (target) cell or from E-UTRA (source) cell to NR (target) cell) . In some implementations, the UE may implement MBS full configuration directly after UE changes to a new serving cell (e.g., UE mobility event in idle mode, such as cell (re) selection procedure while the UE is staying in RRC inactive state or RRC idle state) .

In some implementations, the disclosed (MBS) full configuration may be associated with a specific MBS type. For example, in some implementations, the (MBS) full configuration may be (pre-defined/pre-installed) to be associated with ‘Broadcast Service’ . Therefore, the UE may trigger/initiate the (MBS) full configuration (e.g., the UE may flush the pending (HARQ) buffers associated with all of the running broadcast services) to all of the running Broadcast Services associated with the UE while the UE is triggered to implement full configuration procedure. In contrast, the UE may apply (conventional) full configurations to all of the running Multi-cast services associated with the UE while the UE is triggered to implement full configuration procedure (by the UE’s serving RAN) . In other words, the UE also does not expect that MBS full configuration would be applied to multicast services.

In some implementations, the (MBS) full configuration may be (pre-defined/pre-installed) to be associated with ‘Multi-cast Service’ . Therefore, the UE may trigger/initiate the (MBS) full configuration (e.g., the UE may flush the pending (HARQ) buffers associated with all of the running multicast services) to all of the running Multicast Services associated with the UE while the UE is triggered to implement full configuration procedure. In contrast, the UE may apply (conventional) full configurations to all of the running Broadcast-cast services associated with the UE while the UE is triggered to implement full configuration procedure (by the UE’s serving RAN) . In other words, the UE also does not expect that MBS full configuration would be applied to broadcast services.

System information change: In some implementations, one UE may trigger MBS full configuration procedure when the broadcasting system information (e.g., the MBS-SIB, which provides default MBS radio configurations for the UE to implement MBS reception regardless of the RRC states of the UE) changes. For example, when the system information modification procedure is triggered (e.g., via a short message reception during a paging message monitoring procedure) or the UE notices the value tag of the MBS-SIB changes, the UE may trigger the MBS full configuration procedure to update the MBS radio configurations associated with (at least) one active MBS. In some implementations, the UE may also trigger the MBS full configuration procedure when the MBS-SIB is associated with one {areascope= ’true’ } IE, which indicates that the received MBS-SIB is valid across two or more cells in the serving RAN, and the stored systeminformationareaID associated with the MBS-SIB differs with the systeminformationareaID of the serving cell.

In addition to the handover procedure, the disclosed mechanism may also be applicable to MCG add/change/release procedure, special cell change procedure.

Implicit Approach

In some implementations, the UE may implement (MBS) full configuration procedure implicitly (i.e., the MBS full configuration procedure, configured for a subset or all of the active MBSs at the UE side, may be triggered when the UE does not receive the MBS full configuration indicator to the target MBS (s) of the MBS full configuration procedure) when (at least) one of the following triggering events is fulfilled:

- After receiving Core Network paging message (e.g., while the UE is staying in RRC Inactive state/RRC Idle state) .

- After receiving RAN paging message (e.g., while the UE is staying in RRC Inactive state/RRC Idle state) .

- When the UE triggers RRC re-establishment procedure.

- When the UE triggers RRC resume procedure.

- When the UE triggers RRC establishment procedure.

- When the UE performs Stand-alone Non-Public Network (SNPN) selection procedure or Public land mobile network (PLMN) selection procedure based on upper layer request (e.g., SNPN selection request or PLMN selection request from the NAS layer at the UE side, which may be generated due to SNPN access mode changes) .

- When the serving cell become non-suitable to the UE (e.g., the serving cell could not fulfill S-criteria or the cell is considered as barred by the UE) . In some implementations, the MBS full configuration may be implemented when the UE camps on an ‘acceptable cell’ . In some implementations, the MBS full configuration procedure may be implemented when the UE moves out of the ‘Camped Normally’ state (e.g., the UE moves from the ‘Camped Normally state’ to the ‘Any Cell Selection state’ or ‘Camped on Any Cell state’ ) .

In some implementations, the UE may release/clear the MBS radio configurations associated with one or more MBSs while the MBS session (s) or the PDU session (s) is released (e.g., while the upper layers, such as NAS layer, MBS layer, or service layer informs the AS layer of the UE side that one MBS session (s) /PDU sessions is released) .

Inter-RAT scenario

In some implementations, the UE may receive (MBS) full configuration indicator through dedicated control signaling (e.g., when the UE is instructed to change its serving cell to an E-UTRA cell during a handover or conditional handover procedure) . In an inter-RAT handover procedure,

- the source cell (e.g., the cell configured by a source E-UTRA eNB) may transmit (MBS) full configuration indicator to the UE in the RRCReconfiguration message (with mobilityFromEUTRACommand IE) .

- in addition, in some implementations, the (MBS) full configuration and/or the associated new MBS radio configurations may be generated by the target cell (e.g., the cell configured by a target NR gNB) while the source E-UTRA eNB transmit a handover request message (for the concerned UE) to the target NR gNB through the inter-node signaling delivery (e.g., through the X2 interface or Xn interface) . The handover request message may be transmitted via a backhaul connection between the source E-UTRA eNB and the target NR gNB. Then, the target NR gNB may deliver the (MBS) full configuration indicator and/or new MBS radio configurations to the source E-UTRA eNB. The source eNB (or the source cell) may deliver the received (MBS) full configuration indicator and/or the new MBS radio configurations to the concerned UE.

- in some implementations, the source E-UTRA eNB may also transmit the “MBMS interest indication” (e.g., the MBMS interest indication of E-UTRA protocols, which the UE has transmitted to the source E-UTRA eNB before the concerned inter-RAT handover event) of the concerned UE to the target NR gNB (e.g., through the inter-node control message delivery between the source eNB and the target gNB) through backhaul connection, such as X2 interface or Xn interface.

RAT change event may include: when the UE changes its serving cell from an NR cell to an E-UTRA cell; when the UE changes its serving cell from an E-UTRA cell to an NR cell; when the UE moves from NR RRC Inactive/Idle state to E-UTRA idle state or when the UE moves from E-UTRA RRC Inactive/Idle state to NR idle state.

The disclosed mechanism may also be supported for intra-system/inter-system handover procedure, conditional re-configuration procedure, and DAPS procedure.

MBS Full Configuration

RRC state

In some implementations, UE may apply all (or part) of the disclosed the MBS full configuration only while the UE is staying in the RRC Connected state.

In some implementations, the UE may apply all (or part) of the disclosed MBS full configuration procedure while the UE moves from the RRC Connected state to the RRC Inactive/Idle state. For example, the UE may release the (stored) dedicated MBS radio configuration and then apply the (new) MBS radio configuration that the UE receives from system information of the serving cell while the UE moves from RRC Connected state to RRC Inactive state or RRC Idle state.

In some implementations, the UE may be configured with dedicated MBS radio configurations for UE to access MBS (s) while the UE is staying in the RRC Inactive state (e.g., the dedicated MBS radio configurations may be provided in the RRCRelease with suspendconfig IE. ) . In addition, in this condition, the UE may release the stored dedicated MBS radio configurations when the UE moves to the RRC idle state in some implementations; and the UE may not release the stored dedicated MBS radio configurations when the UE moves to the RRC idle state in some other implementations.

In some implementations, the UE may also apply all (or part) of the disclosed MBS full configuration while the UE is staying in RRC Inactive state or RRC Idle state.

Dedicated MBS Radio Configurations

In some implementations, the UE may release/clear all current dedicated MBS radio configurations. The dedicated MBS radio configuration may include (but not be limited to) the following components:

- Measurement configurations specific for MBS, e.g., CSI-RS measurement configuration on the target frequency carrier, BWP or frequency resources on which the MBS packets are delivered, or the radio configurations associated with the MBS (s) associated with the UE.

- MR-SCG (e.g., NR SCG or E-UTRA SCG) configuration configured for MBS packet reception (if there is any at the UE side) .

- Physical radio resource configurations (e.g., BWP configuration or ranges of physical resource blocks in time domain/frequency domain configured to transmit one or more MBS packets for the MBS (s) associated with the UE) .

- Layer-2 MBS radio configurations, such as MRB/DRB configuration to be associated with one or more PDU session (s) and/or one or more MBS session (s) and/or one or more MBMS session (s) , which are configured to support one or more Multi-cast and/or Broadcast service (s) at the UE side.

The Layer-2 MBS radio configuration may include any combinations of the configurations in the following sublayer:

- SDAP associated with the concerned radio bearer (s) (e.g., DRBs or MRBs) ,

- PDCP configuration associated with the concerned radio bearer (s) (e.g., DRBs or MRBs) ,

- RLC configuration associated with the concerned radio bearer (s) (e.g., DRBs or MRBs) ,

- logical channel (or transport channel) configuration, physical resource configuration associated with the concerned radio bearer (s) (e.g., DRBs or MRBs) .

In some implementations, the UE may release/clear all current dedicated MBS radio configurations except (one or any combinations of) the following components:

- one or more MBS-specific RNTI (s) (e.g., G-RNTI) associated with one or more Multi-cast/Broadcast service. The MBS-specific RNTI may be pre-defined by the technical specification, pre-installed in USIM) , or pre-configured by the serving cell via broadcasting system information or via dedicated UE-specific control signaling (e.g., DL-RRC signaling) .

- the AS security configurations associated with the master key specific for MBS.

Default Setting

In some implementations, default MBS radio configuration/common MBS radio configuration (such as default MRB or default DRB configuration for MBS) may also be transmitted in the (same) broadcasting system information (e.g., the common MBS radio configurations) . In some implementations, after receiving the (MBS) full configuration indicator (e.g., in broadcasting system information or in UE-specific DL RRC signaling) , the UE may release the (stored) dedicated MBS radio configuration and then re-setup the MBS radio configuration for all or a subset of MBS (s) based on the default MRB/DRB configurations received in the system information. In some implementations, the default MBS radio configuration/common MBS radio configuration may be associated with a broadcast service. In some implementations, the default MRB may be a broadcast MRB.

In some implementations, one UE may be configured with one default MBS radio configuration (associated with one or more Multicast Services (s) ) through UE-specific dedicated control signaling. For example, the UE may be configured with one default MBS radio configuration associated with one Multicast service ID in the DL RRC signaling (e.g., RRCReconfiguration message or RRC Release message) . Then, the UE may start to re-configure and apply its own MBS radio configurations of the Multicast service by using the default MBS radio configuration when the UE moves to RRC Inactive state or RRC Idle state.

In some implementations, the UE may apply default L1 parameter values in corresponding physical layer specifications to support the target MBS packet reception.

In some implementations, the UE may apply default L1 parameter values in corresponding physical layer specifications except for parameters for which values are provided in system information. The system information may be SIB1 or other SI specific for MBS radio configuration.

SpCell Change Event

In some implementations, if the spCellConfig in the masterCellGroup includes the reconfigurationWithSync (i.e., SpCell change) , the UE may release/clear all current common radio configurations in the full configuration procedure.

In some implementations, the UE may release/clear all (or part of) current common MBS radio configurations in the MBS full configuration procedure (or full configuration procedure while the MBS full configuration procedure is part of the full configuration procedure at the UE side) . In some implementations, the common MBS radio configuration may only cover MBS Bearer configurations. In some implementations, the common MBS radio configuration may cover MRB configurations and/or DRB configurations. The UE may obtain all of the current common MBS radio configurations through broadcasting system information of the current serving cell (e.g., the source cell in the handover procedure) . The current common MBS radio configurations may also include the physical radio resource configurations and AS sub-layers (e.g., SDAP/PDCP/RLC/MAC) configurations to support one or more MBS services.

In some implementations, the UE may not release/clear all (or part of) current common MBS radio configurations in the MBS full configuration procedure (or full configuration procedure) . Instead, the UE may keep the current common MBS radio configurations during the SpCell change event.

PDU Session Management

In some implementations, the serving cell may configure new DRB configuration and/or new MRB configuration for the concerned UE to support one or more MBS (s) , which may be conveyed by a PDU session configured by the upper layers. Therefore, during the (MBS) full configuration, the UE may determine to release the user plane resources for the concerned PDU session if there are no associated new radio bearer configurations (e.g., neither MRB nor DRB) being provided for the concerned PDU session.

The serving cell may configure new DRB configuration and/or MRB configuration for the UE via broadcasting system information and/or UE-specific DL control signaling (e.g., DL RRC signaling, such as RRCSetup message, RRCrerestablishment message, RRCResume message, RRCReconfiguration message, RRCRelease message) .

In some implementations, the UE may check the drbToAddModList &mrbToAddModList in the DL control signaling (which may also include the ‘MBS full configuration indicator’ and/or ‘full configuration indicator’ ) . For each PDU session that is part of the current UE configuration but not added with same PDU session in the drbToAddModList and mrbToAddModList, the UE may indicate the release of the user plane resources for the PDU session to upper layers. Note that mrbToAddModList may be included in RadioBearerConfig IE. mrbToAddModList may be used to add and/or modify one or multiple MRBs to a UE.

In some implementations, the UE may check the drbToAddModList and/or mrbToAddModList in the DL control signaling (which may also include the ‘MBS full configuration indicator’ and/or ‘full configuration indicator’ ) . In a case that the full reconfiguration procedure is triggered by reconfiguration with sync (or handover) , for each PDU session that is part of the current UE configuration but not added with same PDU session in the drbToAddModList and mrbToAddModList, the UE may indicate the release of the user plane resources for the PDU session to upper layers, after successful reconfiguration with sync (or successfully handover procedure) . In other cases, for each PDU session that is part of the current UE configuration but not added with same PDU session in the drbToAddModList and mrbToAddModList, the UE may indicate the release of the user plane resources for the PDU session (e.g., one MBS session, one Multicast session, one Broadcast session, one Unicast session) to upper layers immediately.

In some implementations, for one PDU session configured to support one (or more) specific MBS, only DRBs may be configured to support the concerned PDU session. In this condition, for each PDU session that is part of the current UE configuration but not added with same PDU session in the drbToAddModList, the UE may indicate the release of the user plane resources for the PDU session to upper layers.

In some implementations, for one PDU session configured to support one (or more) specific MBS, only MRBs may be configured to support the concerned PDU session. In this condition, for each PDU session that is part of the current UE configuration but not added with same PDU session in the mrbToAddModList, the UE may indicate the release of the user plane resources for the PDU session to upper layers.

In contrast, for PDU session that is not configured for MBS (e.g., for unicast service) , the UE may just check the drbToAddModList. For each PDU session that is part of the current UE configuration but not added with same PDU session in the drbToAddModList in the DL control signaling (which may also include the ‘MBS full configuration indicator’ and/or ‘full configuration indicator’ ) , the UE may indicate the release of the user plane resources for the PDU session to upper layers.

In some implementations, the MBS full configuration may be configured as one independent procedure. The UE may be configured with the mrbToAddModList in the received instructions that triggers the UE to implement MBS full configuration (e.g., MBS full configuration transmitted via a DL RRCReconfiguration message or RRCRelease message) . In addition, drbToAddModList may not be configured in the MBS full configuration instruction if one MBS session could not be mapped to be associated with one (or more) DRB (s) to support (at least) one target MBS (e.g., technical specification does not support DRB to be configured with one MBS PDU session) .

In contrast, in some implementations, one UE may be configured with one mrbToAddModList and/or drbToAddModList in the received instructions that triggers the UE to implement MBS full configuration (e.g., MBS full configuration message transmitted via a DL RRCReconfiguration message or RRCRelease message) . In some implementations, the mrbToAddModList may not be configured in one (conventional) full configuration instruction message if conventional full configuration instruction does not cover the disclosed MBS full configuration mechanism.

In some implementations, the AS layer in the UE side (e.g., the RRC entity in the UE side) may identify the PDU session for multicast service, broadcast service, and/or unicast service based on the AS layer configuration (e.g., the DRB/MRB configuration, the service identity associated with PDU session identity, the SDAP layer configuration) . In some implementations, the serving cell may deliver the association between service type (e.g., multi-cast service, broadcast service, unicast service) and the PDU session identity via one DL UE-specific control signaling and/or broadcasting system information or signaling from the upper layers.

If the disclosed (MBS) full configuration procedure is triggered due to reconfiguration with sync procedure, the UE may indicate the release of the user plane resources for the PDU session to upper layers after successful reconfiguration with sync. Otherwise (e.g., the disclosed (MBS) full configuration procedure is not triggered due to reconfiguration with sync procedure) , the UE may indicate the release of the user plane resources for the PDU session to upper layers immediately.

In some implementations, the UE may also check whether common MBS radio configurations, such as the MBS radio configurations delivered by the broadcasting system information (e.g., one MBS-SIB, which may be transmitted by the serving cell via MIB, SIB1, or ‘other SIB’ ) of serving cell, which may also include common MRB configuration or common DRB configuration to support one or more target MBS (s) , may be applied to the existing PDU session. For example,

- for each PDU session that is part of the current UE configuration but not added with same PDU session in neither (new) dedicated MBS radio configuration nor (new) common MBS radio configurations, the UE may indicate the release of the user plane resources for the PDU session to upper layers.

- in contrast, the UE may not indicate the release of the user plane resource for the PDU session to upper layers if (part of) the PDU session could be re-configured (or be re-associated) with either (new) common MBS radio configurations or (new) dedicated MBS radio configurations during the (MBS) full configuration procedure.

- in some implementations, the common MBS radio configuration may be cell-specific, RAN Notification Area-specific, tracking area-specific, or system information area-specific.

- every time when one new (MBS) PDU session is generated (e.g., generated by the upper layers, such as service layer or NAS layer) at the UE side for one or more target MBS (s) , the AS layer may firstly check the MBS-SIB configuration transmitted by the serving cell. Then, the AS layer may provide the AS layer configurations for the new MBS PDU session based on the common MBS radio configuration transmitted via the MBS-SIB.

- the UE may deliver UE requirements for MBS radio configurations to the serving cell if the common MBS radio configurations could not fulfill the QoS or Quality-of-Experience (QoE) requirements of the new (MBS) PDU session or the common MBS radio configuration for the concerned MBS service/PDU session is absent (e.g., MBS-SIB is broadcasted by the serving cell but the common MBS radio configuration for the concerned MBS is absent) . In some implementations, the serving cell may also transmit another indicator (e.g., MBS-Support_RRCConnectedstate indicator=true) in the MBS-SIB to inform the UE whether UE needs to build an active RRC connection with the serving cell to obtain the MBS radio configuration for the concerned MBS. In addition, the UE may be triggered to start an RRC establishment procedure, RRC resume procedure with the serving cell (to obtain the MBS radio configuration of the concerned MBS (s) ) to build or resume the RRC connection between the UE and the serving RAN if one (MBS) PDU session is generated and the “MBS- Support_Connectedstate indicator=true” (associated with the concerned MBS (s) ) is transmitted via the MBS-SIB. In some implementations, the UE may start an RRC establishment procedure, RRC resume procedure with the serving cell (to obtain the MBS radio configuration of the concerned MBS (s) ) to build or resume the RRC connection between the UE and the serving RAN if MBS-SIB is transmitted but the common MBS radio configuration associated with (at) least one concerned MBS is absent.

In some implementations, the User Plane Function (UPF) may deliver the PDU session information for DL data packets (e.g., via DL PDU session information message) , where the PDU session information may include whether the PDU session is associated with multicast service, broadcast service, or unicast service, to the UE. In some implementations, one or more bits (or field) in a DL PDU session information message may be used to indicate whether the PDU session is associated with multicast service, broadcast service, or unicast service. For example, there may be one bit (or field) in the DL PDU session information message to be used to indicate whether the PDU session is associated with multicast service, broadcast service, or unicast service. In another example, there may be one bit (or field) in a DL PDU session information message to be used to indicate whether the PDU session is associated with multicast service. In another example, there may be one bit (or field) in a DL PDU session information message to be used to indicate whether the PDU session is associated with broadcast service. In another example, there may be one bit (or field) in a DL PDU session information message may be used to indicate whether the PDU session is associated with unicast service.

MBS Session Management

In some implementations, the serving cell may configure new DRB configuration and/or new MRB configuration for the concerned UE to support a MBS, which is conveyed by a MBS session/MBMS session configured by the upper layers. One MBS session/MBMS session may be configured to support one or more Multicast/Broadcast service.

For example, during the (MBS) full configuration, the UE may determine to release the user plane resources for the concerned MBS session if there is no associated new radio bearer configurations (e.g., neither MRB nor DRB) being provided for the concerned MBS session. For example, the UE may check the drbToAddModList &mrbToAddModList in the DL control signaling (which may also include the ‘MBS full configuration indicator’ and/or ‘full configuration indicator’ ) . For each MBS session that is part of the current UE configuration but not added with same MBS session in the drbToAddModList or mrbToAddModList, the UE may indicate the release of the user plane resources for the MBS session to upper layers.

In some implementations, for one MBS session configured to support one (or more) specific MBS, only DRBs may be configured to support the concerned MBS session. In this condition, for each MBS session that is part of the current UE configuration but not added with same MBS session in the drbToAddModList, the UE may indicate the release of the user plane resources for the MBS session to upper layers.

In some implementations, the UE may identify to the upper layer that the new DRB/MRB configuration (configured in the drbToAddModList/mrbToAddModList respectively) is connected with by checking the drbToAddModList and/or the mrbToAddModList respectively. For example, in some implementations, one eps-beareridentity (e.g., the eps-beareridentity associated with one mbs session or an upper layer session configured to support one or more MBS (s) ) may be configured to be associated with one new DRB/MRB (e.g., while the upper layer supports EPS protocols and/or does not support SDAP configuration) . In some implementations, one SDAP-configuration may be configured to be associated with one new DRB/MRB (e.g., while the upper layer supports 5GC protocols and/or supports SDAP layer configuration) . In addition, in the SDAP-configuration, one ‘pdu-session identifier’ or one ‘mbs-session identifier’ may be configured for the new DRB/MRB. Therefore, by checking the information elements contained in the drbToAddModList/mrbToAddModList, the UE may identify whether there is any active DRB/MRB configured to be associated with one PDU session/MBS session after the (MBS) full configuration procedure. In some implementations, a PDU session ID within an ID range may indicate that the PDU session identified by the PDU session ID is an MBS PDU session. In some implementations, a PDU session ID not within an ID range may indicate that the PDU session identified by the PDU session ID is an MBS PDU session. It should be noted that the ID range may be pre-configured or pre-specified.

In some implementations, for one MBS session configured to support one (or more) specific MBS, only MRBs may be configured to support the concerned MBS session. In this condition, for each MBS session that is part of the current UE configuration but not added with same MBS session in the mrbToAddModList, the UE may indicate the release of the user plane resources for the MBS session to upper layers.

If the disclosed (MBS) full configuration procedure is triggered due to reconfiguration with sync procedure, the UE may indicate the release of the user plane resources for the MBS session to upper layers after successful reconfiguration with sync. Otherwise (e.g., the disclosed (MBS) full configuration procedure is not triggered due to reconfiguration with sync procedure. For example, cell (re) selection while the UE is staying in RRC Inactive state/RRC Idle state) , the UE may indicate the release of the user plane resources for the MBS-Session to upper layers immediately.

In some implementations, the UE may also check whether common MBS radio configurations may be applied to the existing MBS session/MBMS session. For example, for each MBS session that is part of the current UE configuration but not added with same MBS session in neither dedicated MBS radio configuration nor common MBS radio configurations, the UE may indicate the release of the user plane resources for the MBS session to upper layers.

In contrast, the UE may not indicate the release of the user plane resource for the MBS session to upper layers if (part of) the MBS session may be re-configured (or be re-associated) to either (new) common MBS radio configurations or (new) dedicated MBS radio configurations during the MBS full configuration procedure.

In some implementations, the UE may determine whether to indicate the release of the user plane resource for the concerned MBS session to the upper layers by checking both the common MBS configurations and the dedicated MBS configuration and the related implementations. The UE may determine to indicate the release of the user plane resource for the concerned MBS session to the upper layers if (and only if) the UE could not find associated MBS radio bearer (e.g., DRB/MRB) configurations for the concerned MBS session neither from the dedicated MBS radio configurations nor from the common MBS radio configurations.

Common MBS Radio Configuration v. s. Dedicated MBS Radio Configuration

In some implementations, the UE may only release the dedicated MBS radio configurations (e.g., the MBS radio configurations that the UE obtains from the UE-specific DL control signaling) during the (MBS) full configuration procedure.

In some implementations, the UE may not release the common MBS radio configurations (e.g., the MBS radio configurations that the UE obtains from the broadcasting system information or group-PDCCH control signaling) during the MBS full configuration procedure.

In some implementations, the UE may release both of the dedicated MBS radio configurations and common MBS radio configurations during the MBS full configuration procedure.

In some implementations, the serving cell may deliver one explicit indicator to indicate that which MBS radio configuration (e.g., common MBS radio configurations or dedicated MBS radio configurations) to be released/clear during the MBS full configuration procedure.

In some implementations, the UE may implement the disclosed mechanism to all of the active MBS session during the MBS full configuration procedure.

In some implementations, different UE implementations may be applied by the UE respectively to different MBS session.

In some implementations, the UE may obtain (common/default) MBS radio configurations from its serving cell (e.g., by reading the broadcasting system information from the serving cell) . The UE may access the interested MBS (s) by implementing the (common) MBS radio configurations.

Idle Mode UE Behavior

In some implementations, the UE may only be allowed to access the (common) MBS radio configurations from a ‘suitable cell’ . In other words, the validity of the concerned (common) MBS radio configurations also includes the requirements that the cell should be a ‘suitable cell’ to the UE. The UE may not be allowed to access the (common) MBS radio configurations while the UE is staying in the ‘Any cell selection state’ (e.g., while the UE is staying in RRC Idle state or RRC Inactive state) or ‘Camped on any cell state’ (e.g., while the UE is staying in RRC Idle state) .

In this condition, the UE may implement all (or part) of the disclosed MBS full configuration procedure while the UE moves to ‘Any cell selection state’ or ‘Camped on any cell state. ’

For example, the UE may release all the MRB (s) /DRB (s) which are configured to support one or more concerned MBS (s) based on the (common) MBS radio configurations while the UE moves to ‘Any cell selection state’ or ‘Camped on any cell state.

MBSInterestIndication

FIG. 3 illustrates a process 300 of MBSInterestIndication transmission according to an implementation of the present disclosure. Serving cell 304 transmits MBS-SIB 306 to UE 302, where MBS-SIB 306 indicates MBS radio configuration. Serving cell 304 may be the primary cell of the master cell group (MCG) of UE 302. In some implementations, the MBS radio configuration may be transmitted from serving cell 304 to UE 302 via UE-specific dedicated control signaling (e.g., RRCReconfiguration message) . After receiving the MBS radio configuration, UE 302 may transmit MBSInterestIndication to serving cell 304 to enhance the MBS operation.

Triggering event

In some implementations, the UE may be triggered to transmit the MBSInterestIndication to the serving cell if (at least) one MBS session or the PDU session associated with one or more active MBS is released (e.g., the upper layers may inform the AS layer to release the MBS radio configurations associated with the target MBS session/PDU session) .

However, the UE may not transmit the MBSInterestIndication to the serving cell while the MBS session/PDU session (associated with one or more MBS (s) ) is released based on the instructions from the serving RAN or serving Core Network (e.g., due to (MBS) full configuration procedure (e.g., no new DRB/MRB to be mapped to the concerned MBS session/PDU session) or due to serving CN type change, such as the change from 5GC to EPC (or vice versa) .

When the UE changes its interest/preference to an active MBS, MBS radio configurations of the active MBS may be provided by the serving RAN. In some implementations, with the indication transmission to the serving cell (via MBSInterestIndication message) that UE changes its interest/preference to (at least) one target MBS, the UE may release the MBS radio configurations associated with the target MBS (e.g., MRB configuration associated with the MBS) directly. In some implementations, the UE may release the MBS radio configurations associated with the target MBS (in which the UE has no interest) after the UE receives an ACK message for the MBSInterestIndication message from the serving cell (e.g., while the released MBS radio configurations are configured by the serving cell via a DL UE-specific control signaling, such as RRCReconfiguration message and/or RRCRelease message) .

UE Capability

In some implementations, a UE may report to its serving RAN about whether the UE supports all or any subsets of the disclosed (MBS) full configuration procedure via a UE capability enquiry procedure as described in the 3GPP specifications. In some implementations, a UE may report to its serving RAN about whether the UE supports all or any subsets of the disclosed (MBS) full configuration procedure via a UE assistance information reporting procedure as described in the 3GPP specifications.

Signaling Design

In some implementations, the BS (or the serving cell) may transmit one indicator to enable/disable (or require/instruct) the UE to move to RRC Connected state for MBSInterestIndication message transmission.

In some implementations, the BS (or the serving cell) may transmit one indicator, which may be associated with one target MBS, to enable/disable (or require/instruct) the UE to move to RRC Connected state for MBSInterestIndication message transmission (e.g., requesting (a subset of) MBS radio configurations for one target MBS) for the target MBS. In other words, more than one indicator may be broadcast by the serving cell (e.g., in the MBS-SIB) to further indicate that whether one UE is required to move to RRC Connected state to request (a subset of) MBS radio configurations for the MBS associated with the indicator.

The disclosed MBSInterestIndication message may include (any combination of) the following information elements:

- MBS Interest Indication associated with (at least) one target MBS. In some implementations, the UE may transmit the MBS ID directly as the MBS Interest Indication. In some implementations, the UE may transmit one MBS Interest Indication bitmap, where each bit is associated with one target MBS supported by the serving cell. In some implementations, the sequence of the MBS (s) in the bitmap may be implicitly determined according to the sequence of supported MBS list, which may be broadcast by the serving cell in the MBS-SIB. In some implementations, the UE may inform the serving cell that the UE has no interest to one (or more) MBS (s) by transmitting the MBS Interest Indication to the serving cell. For example, the UE may set the MBS Interest Indication associated with the concerned MBS= ‘false’ or ‘0’ in the MBSInterestIndication message when the MBS session or PDU session of one (or more) MBS (s) is released/finished/terminated/stopped by the upper layers of the UE side.

- MBS Frequency List: List of MBS frequencies which the UE is receiving or has interest to receive one or more target MBS (s) (e.g., the target MBS (s) indicated by the MBS Interest Indication) through the assistance of serving cell.

- MBS-priority: This field indicates whether the UE prioritizes MBS reception over unicast reception. In some implementations, this field is present (e.g., by value ‘true’ ) if the UE prioritizes reception of all listed MBS frequencies over reception of any of the unicast bearers (e.g., SRB/DRB) . Otherwise (e.g., this ‘MBS-priority’ is absent or the value of ‘MBS-priority’ = ’false’ ) , UE may not prioritize MBS reception over unicast reception.

In some implementations, to the MRB (e.g., for the MBS indicated by the UE in the MBSInterestIndication message) , the UE may prioritize both the packets transmitted through the PTM leg and the PTP leg above unicast reception if the MBS-priority= ‘true’ (e.g., no matter whether only one leg, either PTM &PTP leg, is active or both of the legs are active to the MRB) . In some implementations, the UE may only prioritize the PTM leg in the MRB and so the packet reception in the PTP leg may not be prioritized (e.g., so the PTP leg of MRB may be considered as part of unicast reception at the UE side) . In some implementations, the UE may only prioritize the PTP leg in the MRB and so the PTM leg may not be prioritized in comparison with unicast reception.

In some implementations, the serving cell may (re) configure one (or more) DRB (s) to support one MBS session. Under this condition, in some implementations, the DRB (associated with one MBS session or one PDU session for one or more MBS (s) ) may be de-prioritized (e.g., the DRB is considered as part of unicast reception) and so the packet reception of other MRB (s) may have higher priorities than this concerned DRB while the ‘MBS-priority’ = ‘true’ . In some implementations, the DRB (associated with one MBS session or one PDU session for one or more MBS (s) ) may not be de-prioritized in comparison with other active MRB (s) at the UE side while the ‘MBS-priority’ =true (e.g., the DRB associated with the MBS session may still be considered as part of MBS service rather than unicast reception) .

- MBS-InterestBandwidthRange: This field indicates that the UE receives MBS frequency bandwidth configuration in the downlink direction, which may include locations and range of the physical resource blocks or subcarriers in the physical radio resource dimension.

- MBS-RadioConfiguration: This field indicates the radio parameters that the UE prefers, such as the subcarrier spacing in the associated interested frequency list, Interest BWP ID (based on the BWP configuration configured by the serving cell in the corresponding MBS frequency carrier (s) ) , preferred cyclic prefix length associated with these corresponding MBS frequency carrier (s) , etc.

Signaling approach

Dual Connectivity: While the UE is configured with dual connectivity, the UE may transmit the MBSInterestIndication to the serving cell (e.g., Primary Cell) or the master node (e.g., MeNb or MgNb) through the assistance of Primary Secondary cell. For example, the UE may be allowed to transmit the MBSInterestIndication message to the PSCell (or secondary Node, such as SeNb, SgNb) in the airlink through SRB3. Then, the PSCell (or the secondary node in the DC scenario) may help to transmit the MBSInterestIndication to the PCell (e.g., through the backhaul connection between the master node and the secondary node, such as X2 interface or Xn interface) .

Inter-node signaling: In some implementations, the serving cell (or serving RAN) of the UE may store the information in the ‘MBSInterestIndication’ as part of UE context after the serving RAN receives the MBSInterestIndication message from the UE. In addition, the information elements in the MBSInterestIndication message may be delivered by base stations through the backhaul connection as part of inter-node signaling exchange.

Context fetch procedure: In some implementations, the information elements in the ‘MBSInterestIndication’ message may be stored as part of the ‘UE Inactive context’ while the UE moves to (LTE/NR) RRC Inactivate state. So, while the UE moves to RRC Inactive state (e.g., after receiving the RRCRelease message with suspend configuration IE) , both of the UE and the serving cell (which may also be called as ‘anchor cell’ to the concerned UE) may store any combination of the IEs in the ‘MBSInterestIndication’ message. In addition, while the UE is staying in the RRC Inactive state, the UE may start RRC Resume procedure with another target cell (which may be located in a base station different with that of the anchor cell) while the UE wants to move back to RRC Connected state or while the UE wants to perform a RAN Notification Area Update procedure. In these conditions, the target cell may deliver one ‘Context Fetch Request’ message to the anchor cell based on the information that the concerned UE transmits to the target cell during the RRC Resume procedure (e.g., based on the (Inactive) UE ID or cell identity of the anchor cell which the UE has transmitted to the target cell via one UL UE-specific control signaling (e.g., RRCResumeRequest message) during the random access procedure (e.g., MSGA in a 2-step RA procedure or MSG3 in a 4-step RA procedure) triggered as part of the RRC Resume procedure) . Then, after receiving the Context Fetch Request message from the target cell, the anchor cell may transmit (any combinations of) the IEs in (at least) part of the UE (Inactive) Context to the target cell (e.g., as part of inter-node signaling between the anchor cell and the target cell through X2/Xn backhaul interface) .

RRC Resume procedure triggering: In some implementations, the UE staying in RRC Inactive state may be triggered to transmit the disclosed ‘MBSInterestIndication’ message to the serving cell (or camped cell) while the UE changes its preference or interest to one (or more) target MBS (s) .

(Conditional) handover procedure: (part of) the context fetch procedure may also be applied to handover procedure (and/or conditional handover procedure) . Firstly, the serving cell of the UE (which may be called ‘source cell’ in the (conditional) handover procedure) may transmit ‘Handover Request’ message to one or more candidate cells via backhaul connections (wherein the candidate cells may be decided based on the measurement reports that the UE has transmitted to the source cell) . Then, one or more of the candidate cells may reply ‘Handover command’ message to the source cell to enable/allow the UE to handover to the corresponding candidate cell. After receiving the ‘Handover command’ message from the one or more candidate cells, the source cell may transmit (any combination of) the stored MBSInterestIndication as part of UE context to these candidate cell that replies ‘Handover command’ message to the source cell for the concerned UE. In some implementations, the source cell may transmit (any combination of) the stored MBSInterestIndication as part of UE context to the candidate cells in the ‘Handover Request’ messages.

The UE may transmit ‘MBSInterestIndication’ to the target cell after handover procedure success for update. In some conditions, the UE may be triggered to deliver one updated MBSInterestIndication message to the target cell.

In some implementations, the UE may trigger the disclosed ‘MBSInterestIndication’ message delivery procedure while (at least one of) the following requirements is fulfilled:

- The target cell delivers the MBS-SIB to the UE. The MBS-SIB may be transmitted to the UE by the DL dedicated control signaling, such as RRC (Connection) Reconfiguration message with reconfigurationwithsync (or mobilitycontrolinfo, which are generated by the source cell) . The MBS-SIB may also be broadcast by the target cell by system information delivery procedure; and/or

- The UE changes its interest for one or more MBS service (for a short time span) before or during the handover procedure is initiated/triggered (e.g., being initiated/triggered by the source cell for a handover procedure or by the UE itself for a conditional reconfiguration or conditional handover procedure) . For example, the UE initiated transmission of a MBSInterestIndication message indicating a change of preferred MBS radio configurations related parameters relevant in target Cell (e.g., target PCell) during the last 1 second preceding reception of the RRCReconfiguration message including reconfigurationWithSync in spCellConfig of a Master Cell Group (MCG) ;

- in some implementations, the UE may transmit the updated MBSInterestIndication message to the target cell during the RA procedure of (conditional) handover procedure (e.g., via the RRCReconfigurationComplete message generated by the UE for the target cell. The RRCReconfigurationComplete message may be transmitted by the UE in in a (contention-free/contention-based) 2-step RA procedure or in a (contention-free/contention-based) 4-step RA procedure) . In some implementations, the UE may transmit the updated MBSInterestIndication message to the target cell after the RA procedure (e.g., after the UE transmits the RRCReconfigurationComplete message to the target cell or along with the RRCReconfigurationComplete message to the target cell) .

Small Data transmission: In some implementations, the UE may be configured with (Type1/Type2) uplink configured grant (UL-CG) configuration and/or Random Access resource configurations for the UE to implement small data transmission procedure while the UE is staying in (NR/LTE) RRC Inactive state. In this scenario, the UE may transmit the ‘MBSInterestIndication’ message to the serving cell by using the configured UL configuration and/or RA resource configured for small data transmission (SDT) procedures. In some implementations, the UL-CG configuration and/or RA configuration may be configured on Normal UL (NUL) carrier and/or Supplementary UL carrier and so the UE may transmit the ‘MBSInterestindication’ on the corresponding NUL and/or SUL carrier after the UE has selected one target UL carrier (among the NUL and SUL) for the Small Data Transmission procedure. In addition, the UE may also be able to transmit the ‘MBSInterestIndication’ message on the subsequent (data) transmissions during a SDT procedure.

The disclosed mechanism may also be applicable to Dual Active Protocol Stack (DAPS) configuration.

FIG. 4 illustrates a method 400 performed by a UE for MBS service management according to an implementation of the present disclosure. In action 402, the UE receives a first radio bearer configuration from a first cell. In action 404, the UE configures a first MRB and an associated first MBS session for a first MBS according to the first radio bearer configuration, the first MBS session having a first MBS session ID. The first MBS session ID may be TMGI #1. In action 406, the UE receives a full configuration indicator associated with a second radio bearer configuration from the first cell, the second radio bearer configuration including at least one of an MRB configuration or a DRB configuration. For example, if the second radio bearer configuration is associated with a cell that does not support MBS, the second radio bearer configuration may include only the DRB configuration but not the MRB configuration. In action 408, the UE performs a full configuration procedure according to the full configuaration indicator. In action 410, the UE determines whether to maintain or release the first MBS session ID and the associated first MBS session based on a service type of the first MBS and the second radio bearer configuration.

In some implementations, the UE may determine to maintain the first MBS session and the associated first MBS session ID in a case that the first MBS session ID is associated with the at least one of the MRB configuration or the DRB configuration in the second radio bearer configuration. Under this condition, the first MBS session ID (e.g., TMGI #1) may be kept during the full configuration procedure. Further, the first MBS session ID may be mapped to one of the DRB configuration in the second radio bearer configuration during the full configuration procedure.

In some implementations, the UE may determine to release the first MBS session and the associated first MBS session ID in a case that the first MBS session ID is not associated with any one of the at least one of the MRB configuration or the DRB configuration in the second radio bearer configuration.

In some implementations, the UE may determine to maintain the first MBS session (e.g., during the full configuration procedure) in a case that the service type of the first MBS is a broadcast service and the first MRB is a broadcast MRB. In some implementaiotns, the broadcast MRB may belong to the default MBS radio configuration or the common MBS radio configuration.

In some implementations, the UE may determine to release the first MBS session (e.g., during the full configuration procedure) in a case that the service type of the first MBS is a multicast service and the first MRB is a multicast MRB.

The full configuration indicator in step 406 may be received via a handover instruction or a conditional handover instruction. The UE may perform the full configuration procedure when switching from a source cell to a target cell according to the handover instruction or the conditional handover instruction.

In some implementations, the full configuration indicator may be transmitted via a handover instruction, which is generated by a second cell and is transmitted to the first cell via a backhaul connection between the first cell and the second cell. The full configuration procedure may be performed after the UE receives the handover instruction to handover to the second cell. The backhaul connection may be inter-node signaling such as X2 interface or Xn interface.

Each of the first cell and the second cell is one of an E-UTRA cell and an NR cell. In some implementations, the handover may be an inter-RAT handover. For example, the first cell may be an E-UTRA cell and the second cell may be an NR cell. Alternatively, the first cell may be an NR cell and the second cell may be an E-UTRA cell.

In some implementations, the full configuration indicator may be transmitted via a conditional handover instruction, which is generated by a third cell and is transmitted to the first cell via a backhaul connection between the first cell and the third cell. The full configuration procedure may be performed after the UE determines to handover to the third cell based on the conditional handover instruction. The backhaul connection may be inter-node signaling such as X2 interface or Xn interface.

Each of the first cell and the third cell is one of an E-UTRA cell and an NR cell. In some implementations, the handover may be an inter-RAT handover. For example, the first cell may be an E-UTRA cell and the second cell may be an NR cell. Alternatively, the first cell may be an NR cell and the second cell may be an E-UTRA cell.

In some implementations, the UE may be configured with multi-connectivity (MC) functionality to communicate with one or more serving base stations simultaneously. When the UE is configured with MC functionality, the full configuration indicator may be received by the UE via one of a Signaling Radio Bearer 1 (SRB1) and a Signaling Radio Bearer 3 (SRB3) , where the SRB1 is constructed between the UE and a primary cell, and the SRB3 is constructed between the UE and a primary secondary cell.

FIG. 5 is a block diagram illustrating a node 500 for wireless communication according to an implementation of the present disclosure. As illustrated in Fig. 5, a node 500 may include a transceiver 520, a processor 528, a memory 534, one or more presentation components 538, and at least one antenna 536. The node 500 may also include a Radio Frequency (RF) spectrum band module, a BS communications module, a network communications module, and a system communications management module, Input /Output (I/O) ports, I/O components, and a power supply (not illustrated in Fig. 5) .

Each of the components may directly or indirectly communicate with each other over one or more buses 540. The node 500 may be a UE or a BS that performs various functions disclosed with reference to FIGS. 1 through 4.

The transceiver 520 has a transmitter 522 (e.g., transmitting/transmission circuitry) and a receiver 524 (e.g., receiving/reception circuitry) and may be configured to transmit and/or receive time and/or frequency resource partitioning information. The transceiver 520 may be configured to transmit in different types of subframes and slots including but not limited to usable, non-usable and flexibly usable subframes and slot formats. The transceiver 520 may be configured to receive data and control channels.

The node 500 may include a variety of computer-readable media. Computer-readable media may be any available media that may be accessed by the node 500 and include both volatile and non-volatile media, removable and non-removable media.

The computer-readable media may include computer storage media and communication media. Computer storage media include both volatile and non-volatile, removable and non-removable media implemented in any method or technology for storage of information such as computer-readable instructions, data structures, program modules or data.

Computer storage media include RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, Digital Versatile Disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices. Computer storage media do not include a propagated data signal. Communication media typically embody computer-readable instructions, data structures, program modules or other data in a modulated data signal such as a carrier wave or other transport mechanism and include any information delivery media.

The term “modulated data signal” means a signal that has one or more of its characteristics set or changed in such a manner as to encode information in the signal. Communication media include wired media such as a wired network or direct-wired connection, and wireless media such as acoustic, RF, infrared and other wireless media. Combinations of any of the previously listed components should also be included within the scope of computer-readable media.

The memory 534 may include computer-storage media in the form of volatile and/or non-volatile memory. The memory 534 may be removable, non-removable, or a combination thereof. Example memory includes solid-state memory, hard drives, optical-disc drives, etc. As illustrated in Fig. 5, the memory 534 may store computer-readable, computer-executable instructions 532 (e.g., software codes) that are configured to cause the processor 528 to perform various disclosed functions, for example, with reference to FIGS. 1 through 4. Alternatively, the instructions 532 may not be directly executable by the processor 528 but be configured to cause the node 500 (e.g., when compiled and executed) to perform various disclosed functions.

The processor 528 (e.g., having processing circuitry) may include an intelligent hardware device, e.g., a Central Processing Unit (CPU) , a microcontroller, an ASIC, etc. The processor 528 may include memory. The processor 528 may process data 530 and the instructions 532 received from the memory 534, and information transmitted and received via the transceiver 520, the base band communications module, and/or the network communications module. The processor 528 may also process information to be sent to the transceiver 520 for transmission via the antenna 536 to the network communications module for transmission to a core network.

One or more presentation components 538 present data indications to a person or another device. Examples of presentation components 538 include a display device, a speaker, a printing component, and a vibrating component, etc.

In view of the present disclosure, it is obvious that various techniques may be used for implementing the concepts in the present disclosure without departing from the scope of those concepts. Moreover, while the concepts have been disclosed with specific reference to certain implementations, a person of ordinary skill in the art will recognize that changes may be made in form and detail without departing from the scope of those concepts. As such, the disclosed implementations are to be considered in all respects as illustrative and not restrictive. It should also be understood that the present disclosure is not limited to the particular implementations disclosed and many rearrangements, modifications, and substitutions are possible without departing from the scope of the present disclosure.

Claims

A method performed by a user equipment (UE) for Multicast Broadcast Service (MBS) service management, the method comprising:

receiving a first radio bearer configuration from a first cell;

configuring a first Multicast Radio Bearer (MRB) and an associated first MBS session for a first MBS according to the first radio bearer configuration, the first MBS session having a first MBS session identifier (ID) ;

receiving a full configuration indicator associated with a second radio bearer configuration from the first cell, the second radio bearer configuration including at least one of an MRB configuration or a Data Radio Bearer (DRB) configuration;

performing a full configuration procedure according to the full configuration indicator; and

determining whether to maintain or release the first MBS session ID and the associated first MBS session based on a service type of the first MBS and the second radio bearer configuration.
The method of claim 1, wherein the first MBS session and the associated first MBS session ID are maintained by the UE in a case that the first MBS session ID is associated with the at least one of the MRB configuration or the DRB configuration in the second radio bearer configuration.
The method of claim 1, wherein the first MBS session and the associated first MBS session ID is released by the UE in a case that the first MBS session ID is not associated with any one of the at least one of the MRB configuration or the DRB configuration in the second radio bearer configuration.
The method of claim 1, wherein the first MBS session is maintained by the UE in a case that the service type of the first MBS is a broadcast service and the first MRB is a broadcast MRB.
The method of claim 1, wherein:

the full configuration indicator is transmitted via a handover instruction, which is generated by a second cell and is transmitted to the first cell via a backhaul connection between the first cell and the second cell; and

the full configuration procedure is performed after the UE receives the handover instruction to handover to the second cell.
The method of claim 5, wherein:

each of the first cell and the second cell is one of an Evolved Universal Terrestrial Radio Access (E-UTRA) cell and a New Radio (NR) cell.
The method of claim 1, wherein:

the full configuration indicator is transmitted via a conditional handover instruction, which is generated by a third cell and is transmitted to the first cell via a backhaul connection between the first cell and the third cell; and

the full configuration procedure is performed after the UE determines to handover to the third cell based on the conditional handover instruction.
The method of claim 7, wherein:

each of the first cell and the third cell is one of an Evolved Universal Terrestrial Radio Access (E-UTRA) cell and a New Radio (NR) cell.
The method of claim 1, wherein the first MBS session is released by the UE in a case that the service type of the first MBS is a multicast service and the first MRB is a multicast MRB.
The method of claim 1, wherein:

the full configuration indicator is received by the UE via one of a Signaling Radio Bearer 1 (SRB1) and a Signaling Radio Bearer 3 (SRB3) while the UE is configured with multi-connectivity (MC) functionality to communicate with one or more serving base stations simultaneously;

the SRB1 is constructed between the UE and a primary cell; and

the SRB3 is constructed between the UE and a primary secondary cell.
A user equipment (UE) for Multicast Broadcast Service (MBS) service management, the UE comprising:

one or more processors; and

at least one memory coupled to at least one of the one or more processors, wherein the at least one memory stores a computer-executable program that, when executed by the at least one of the one or more processors, causes the UE to perform the method of any of claims 1 to 10.