Management of Notifications Regarding Multicast and Broadcast Services

Abstract

A central unit (CU) and a distributed unit (DU) of a distributed base station (BS) in a radio access network (RAN) may implement a method for managing paging of a multicast and broadcast service (MBS). The method includes receiving an identifier of an MBS session and an identifier of a user equipment (UE) from a core network (CN), sending one or more messages including the identifier of the MBS session and the identifier of the UE to the DU, sending one or more parameters for paging associated with the MBS session to the DU, and sending one or more MBS data packets to be broadcast to the UE according to the one or more parameters.

Description

Technical Field

[0001] The present disclosure relates to wireless communication, and more particularly, to paging a UE for one or more multicast and / or broadcast services (MBS).

Background Art

[0002] The description of the background art provided herein is for the purpose of schematically presenting the context of the present disclosure. The research of the inventors, as currently named, is not, to the extent described in this background art section, necessarily considered prior art at the time of filing in the same way as aspects of this specification that may not be considered prior art in some cases. It is not admitted, explicitly or implicitly, as prior art to the present disclosure.

[0003] In a telecommunication system, the packet data convergence protocol (PDCP) sublayer of the radio protocol stack provides services such as transfer, encryption, and integrity protection of user plane data. For example, the PDCP layer defined for evolved universal terrestrial radio access (EUTRA) radio interface (see 3GPP (registered trademark, the same below) specification TS 36.323) and new radio (NR) (see 3GPP specification TS 38.323) provides sequencing of protocol data units (PDUs) in the uplink direction (from a user device, also known as a user equipment (UE), to a base station) and in the downlink direction (from the base station to the UE). Further, the PDCP sublayer provides a service for signaling radio bearers (SRBs) to the radio resource control (RRC) sublayer. The PDCP sublayer also provides a service for data radio bearers (DRBs) to protocol layers such as the service data adaptation protocol (SDAP) sublayer or the Internet protocol (IP) layer, Ethernet protocol layer, and Internet control message protocol (ICMP) layer. Generally, the UE and the base station can use SRBs to exchange RRC messages and non-access stratum (NAS) messages, and can use DRBs to transport data on the user plane.

[0004] A UE communicating with a base station operating according to 5G, 6G, or future generation requirements may support a 100 MHz bandwidth within frequency range 1 (FR1) and a 400 MHz bandwidth within frequency range 2 (FR2). Due to the relatively wide bandwidth of a typical carrier, such a base station can provide multicast and / or broadcast services (MBS) to UEs used in many content delivery applications such as transparent IPv4 / IPv6 multicast delivery, IPTV, software delivery via wireless, group communication, IoT applications, V2X applications, and emergency messages related to public safety.

[0005] To provide a multicast and / or broadcast service (MBS), a base station can configure one or more UEs using a common frequency resource (CFR) and a PDCCH configuration that constitutes a group common physical downlink control channel (PDCCH). The base station can assign a group common radio network temporary identifier (RNTI) to a UE to receive a physical downlink shared channel (PDSCH) transmission including an MBS data packet. Then, the base station can send downlink control information (DCI) to the UE to schedule a PDSCH transmission including an MBS data packet.

Prior Art Documents

Non-Patent Documents

[0006]

Non-Patent Document 1

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Non-Patent Document 3

Non-Patent Document 4

Non-Patent Document 5

Summary of the Invention

Means for Solving the Problems

[0007] A network node provides and manages MBS for one or more UEs that are in an inactive state or an idle state. To start an MBS session with one or more UEs, a distributed unit (DU) of a radio access network (RAN) having a distributed architecture transmits an identifier of the MBS session through one or more paging messages to cause the UE to start MBS communication. Then, the DU broadcasts MBS data packets to the UE according to a resource configuration.

[0008] Furthermore, the Central Unit (CU) of the distributed RAN enables communication between the DU and the MBS network, and provides the DU with an identifier of the MBS session and parameters for paging or a resource configuration for the MBS session. In some cases, the CU may also provide the DU with one or more paging configurations for use when paging the UE and / or communicating with the UE.

[0009] One exemplary embodiment of these techniques is a method for managing paging of MBS in a distributed architecture implemented in the CU. The method includes receiving, by processing hardware, from the CN, an identifier of an MBS session and an identifier of a UE; transmitting, by processing hardware, to the DU, one or more messages including the identifier of the MBS session and the identifier of the UE; transmitting, by processing hardware, to the DU, one or more parameters for paging associated with the MBS session; and transmitting, by processing hardware, to the DU, one or more MBS data packets to be broadcast to the UE according to the one or more parameters.

[0010] Another exemplary embodiment of these techniques is a method for managing paging of MBS in a distributed architecture implemented in the DU. The method includes receiving, by processing hardware, from the CU, an identifier of an MBS session and an identifier of a UE; transmitting, by processing hardware, to the UE corresponding to the identifier of the UE, one or more paging messages including the identifier of the MBS session when one or more radio connections between the UE and the DU are inactive; and subsequently transmitting, by processing hardware, to the UE, one or more MBS data packets to be broadcast according to one or more MBS resource configurations. BRIEF DESCRIPTION OF THE DRAWINGS

[0011]

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DETAILED DESCRIPTION OF THE INVENTION

[0012] Generally, the techniques of the present disclosure enable a UE to receive MBS information via radio resources allocated by a base station of a RAN. For this purpose, the base station can configure different radio resources in one or more overlapping cells to multicast or broadcast MBS data (and related control information) and / or unicast non-MBS data (and related control information) to one or more UEs on the downlink (DL). Note that "transmit" by the base station may equivalently refer to "multicast", "broadcast", and / or "unicast". The base station can also unicast MBS data (and related control information) to a UE on a dedicated DRB for the UE. One or more UEs can transmit non-MBS data to the base station on the uplink (UL).

[0013] Accordingly, the base station of the present disclosure can configure one or more radio bearers for transmitting MBS information (i.e., MBS data packets and / or control information) to a UE. The radio bearer for carrying MBS information to the UE can be a unicast DRB (i.e., a dedicated DRB for the UE) or a multicast DRB (i.e., a DRB that can be shared by multiple UEs, also referred to as an MBS radio bearer or MRB). For example, the base station can transmit unicast configuration parameters or multicast configuration parameters to the UE to configure the UE to receive MBS information via a unicast DRB or a multicast DRB, respectively. As used in the present disclosure, the term DRB may refer to a unicast DRB or a multicast DRB unless otherwise specified.

[0014] FIG. 1A illustrates an exemplary wireless communication system 100 that can implement the MBS operation technique of the present disclosure. The wireless communication system 100 includes user equipments (UEs) 102A and 102B, and base stations 104, 106A, 106B of a radio access network (RAN) (e.g., RAN 105) connected to a core network (CN) 110. For ease of reading, UE 102 is used herein to represent UE 102A, UE 102B, or both UE 102A and UE 102B, unless otherwise specified. The base stations 104, 106A, 106B can be any suitable one or more types of base stations, such as evolved Node B (eNB), next-generation eNB (ng-eNB), 5G Node B (gNB), or 6G base stations. As a more specific example, the base station 104 can be an eNB or a gNB, and the base stations 106A and 106B can be gNBs.

[0015] Base station 104 supports cell 124, base station 106A supports cell 126A, and base station 106B supports cell 126B. Cell 124 partially overlaps with both cells 126A and 126B. As a result, UE 102 can be within range to communicate with base station 104 while also being within range to communicate with base station 106A or 106B simultaneously (or within range to detect or measure signals from both base stations 106A and 106B). The overlap can enable UE 102 to perform handovers between cells (e.g., from cell 124 to cell 126A or 126B) or between base stations (e.g., from base station 104 to base station 106A or base station 106B) before UE 102 experiences a radio link failure. Further, the overlap enables UE 102 to operate in dual connectivity (DC) with RAN 105. For example, UE 102 can communicate in DC with base station 104 (operating as a master node (MN)) and base station 106A (operating as a secondary node (SN)), and when the handover to base station 106B is complete, it can communicate with base station 106B (operating as an MN). As another example, UE 102 can communicate in DC with base station 104 (operating as an MN) and base station 106A (operating as an SN), and when the SN change is complete, it can communicate with base station 104 (operating as an MN) and base station 106B (operating as an SN).

[0016] More specifically, when UE 102 is in DC with base station 104 and base station 106A, base station 104 operates as a master eNB (MeNB), a master ng-eNB (Mng-eNB), or a master gNB (MgNB), and base station 106A operates as a secondary gNB (SgNB) or a secondary ng-eNB (Sng-eNB).

[0017] In non-MBS (i.e., unicast) operation, UE 102 can use radio bearers (e.g., DRBs or SRBs) that terminate at the MN (e.g., base station 104) or SN (e.g., base station 106) at different times. For example, after a handover to base station 106B or an SN change, UE 102 can use radio bearers (e.g., DRBs or SRBs) that terminate at base station 106B at different times. UE 102 can apply one or more security keys when communicating on a radio bearer in the uplink (UL) direction (i.e., from UE 102 to the base station) and / or the downlink (DL) direction (i.e., from the base station to UE 102). In non-MBS operation, UE 102 transmits data to the base station via a radio bearer on the uplink BWP of the cell (i.e., within the uplink BWP) and / or receives data from the base station via a radio bearer on the DL BWP of the cell. The UL BWP can be the initial UL BWP or a dedicated UL BWP, and the DL BWP can be the initial DL BWP or a dedicated DL BWP. UE 102 can receive paging, system information, public warning messages, or random access responses on the DL BWP. In such non-MBS operation, UE 102 can be in a connected state. Alternatively, if UE 102 supports small data transmission in the idle or non-active state, UE 102 can be in the idle or non-active state.

[0018] In the MBS operation, the UE 102 can use radio bearers (e.g., DRB or MRB) that terminate at the MN (e.g., base station 104) or the SN (e.g., base station 106A) at different times. For example, after a handover to base station 106B or an SN change, the UE 102 can use radio bearers (e.g., DRB or MRB) that terminate at base station 106B, which can be the MN or the SN at different times. The base station can utilize radio bearers to transmit application-level messages, such as security keys, to the UE 102. In some implementations, the base station (e.g., the MN or the SN) can transmit MBS data to the UE 102 (e.g., via a DRB or an MRB) over dedicated radio resources (i.e., radio resources dedicated to the UE 102). In such implementations, the base station can apply one or more security keys to protect the integrity of and / or encrypt the MBS data and transmit the encrypted and / or integrity-protected MBS data to the UE 102 over the dedicated radio resources. Correspondingly, when receiving MBS data on a radio bearer in the downlink direction (from the base station to the UE 102), the UE 102 can apply one or more security keys to decrypt the MBS data and / or inspect the integrity of the MBS data. In other implementations, the base station (e.g., the MN or the SN) can transmit MBS data from the base station to the UE 102 (e.g., via a DRB or an MRB) over common radio resources (i.e., radio resources common to the UE 102 and other UEs, such as a common frequency resource (CFR)) or via the DL BWP of the cell. The DL BWP can be an initial DL BWP, a dedicated DL BWP, or an MBS DL BWP (i.e., a DL BWP specific to MBS rather than unicast). In such implementations, the base station can refrain from applying security keys to the MBS data and can transmit the MBS data on the radio bearer. Correspondingly, the UE 102 can omit applying security keys to the MBS data received on the radio bearer.UE102 can apply the application-level security key received from the CN110 or the MBS server to the MBS data received on the radio bearer.

[0019] The base station 104 includes processing hardware 130, and the processing hardware 130 can include one or more general-purpose processors (e.g., a central processing unit (CPU)), and a computer-readable memory storing machine-readable instructions executable on the one or more general-purpose processors, and / or a dedicated processing unit. The processing hardware 130 in the exemplary implementation of FIG. 1A includes a base station MBS controller 132 configured to manage or control the transmission of MBS information received from the CN110 or the edge server. For example, the base station MBS controller 132 can be configured to support radio resource control (RRC) configurations, procedures, and messaging associated with MBS procedures, and / or to support the necessary operations (e.g., MBS activation notification), as discussed below. The processing hardware 130 can include a base station non-MBS controller 134 configured to manage or control one or more RRC configurations and / or RRC procedures when the base station 104 operates as an MN or an SN during non-MBS operations.

[0020] The base station 106A includes processing hardware 140, which can include one or more general-purpose processors (e.g., CPUs), and a computer-readable memory storing machine-readable instructions executable on the general-purpose processor, and / or dedicated processing units. The processing hardware 140 in the exemplary implementation of FIG. 1A includes a base station MBS controller 142 configured to manage or control the transmission of MBS information received from CN110 or the edge server. For example, the base station MBS controller 142 can be configured to support RRC configurations, procedures, and messaging associated with the MBS procedure and / or support the necessary operations (e.g., MBS activation notification) as discussed below. The processing hardware 140 can include a base station non-MBS controller 144 configured to manage or control one or more RRC configurations and / or RRC procedures when the base station 106A operates as an MN or SN during non-MBS operation. Although not shown in FIG. 1A, the base station 106B can include processing hardware similar to the processing hardware 130 of the base station 104 or the processing hardware 140 of the base station 106A.

[0021] UE 102 includes processing hardware 150, which can include one or more general-purpose processors (e.g., CPU), a computer-readable memory storing machine-readable instructions executable on the general-purpose processor, and / or a dedicated processing unit. The processing hardware 150 in the exemplary implementation of FIG. 1A includes a UE MBS controller 152 configured to manage or control the reception of MBS information. For example, the UE MBS controller 152 can be configured to support the RRC configurations, procedures, and messaging associated with MBS procedures and / or to support the necessary operations (e.g., MBS activation notification) as discussed below. The processing hardware 150 can include a UE non-MBS controller 154 configured to manage or control one or more RRC configurations and / or RRC procedures according to any of the implementations discussed below when the UE 102 communicates with the MN and / or SN during non-MBS operations.

[0022] CN 110 can be an evolved packet core (EPC) 111 or a 5th generation core (5GC) 160, both of which are illustrated in FIG. 1A. The base station 104 can be an eNB supporting an S1 interface for communicating with the EPC 111, an ng-eNB supporting an NG interface for communicating with the 5GC 160, or a gNB supporting an NR radio interface and an NG interface for communicating with the 5GC 160. The base station 106A can be an EUTRA-NR DC (EN-DC) gNB (en-gNB) having an S1 interface to the EPC 111, an en-gNB not connected to the EPC 111, a gNB supporting an NR radio interface and an NG interface to the 5GC 160, or an ng-eNB supporting an EUTRA radio interface and an NG interface to the 5GC 160. The base stations 104, 106A, and 106B can support an X2 or Xn interface to directly exchange messages with each other during the scenarios discussed below.

[0023] Among the components, EPC111 can include a Serving Gateway (SGW) 112, a Mobility Management Entity (MME) 114, and a Packet Data Network Gateway (PGW) 116. The SGW112 is generally configured to transfer user plane packets related to, for example, audio calls, video calls, Internet traffic, etc. The MME114 is configured to manage authentication, registration, paging, and other related functions. The PGW116 provides connectivity from the UE to one or more external packet data networks, such as the Internet network and / or the Internet Protocol (IP) Multimedia Subsystem (IMS) network. 5GC160 includes a User Plane Function (UPF) 162, an Access and Mobility Management (AMF) 164, and / or a Session Management Function (SMF) 166. The UPF162 is generally configured to transfer user plane packets related to, for example, audio calls, video calls, Internet traffic, etc. The AMF164 is configured to manage authentication, registration, paging, and other related functions. The SMF166 is configured to manage PDU sessions. The UPF162, AMF164, and / or SMF166 can be configured to support MBS. For example, the SMF166 can be configured to manage or control MBS transport, configure the UPF162 and / or RAN105 for MBS flows, and / or manage or configure an MBS session or PDU session for MBS for the UE102. The UPF162 is configured to transfer MBS data packets for audio, video, Internet traffic, etc. to the RAN105. The UPF162 and / or SMF166 can be configured for both unicast services and MBS, or for MBS only.

[0024] Generally, the wireless communication network 100 can include any suitable number of base stations that support NR cells and / or EUTRA cells. More specifically, the EPC 111 or 5GC 160 can be connected to any suitable number of base stations that support NR cells and / or EUTRA cells. The following examples specifically refer to certain CN types (EPC, 5GC) and RAT types (5G NR and EUTRA), but generally, the techniques of the present disclosure can be applied to other suitable radio access and / or core network technologies, such as, for example, 6th generation (6G) wireless access and / or 6G core network or 5G NR-6G DC.

[0025] In different configurations or scenarios of the wireless communication system 100, the base station 104 can operate as a MeNB, Mng-eNB, or MgNB, the base station 106B can operate as a MeNB, Mng-eNB, MgNB, SgNB, or Sng-eNB, and the base station 106A can operate as an SgNB or Sng-eNB. The UE 102 can communicate with the base station 104 and the base station 106A or 106B via the same radio access technology (RAT), such as EUTRA or NR, or via different RATs.

[0026] When the base station 104 is a MeNB and the base station 106A is an SgNB, the UE 102 can be in EN-DC with the MeNB 104 and the SgNB 106A. When the base station 104 is a Mng-eNB and the base station 106A is an SgNB, the UE 102 can be in next-generation (NG) EUTRA-NR DC (NGEN-DC) with the Mng-eNB 104 and the SgNB 106A. When the base station 104 is a MgNB and the base station 106A is an SgNB, the UE 102 can be in NR-NR DC (NR-DC) with the MgNB 104 and the SgNB 106A. When the base station 104 is a MgNB and the base station 106A is an Sng-eNB, the UE 102 can be in NR-EUTRA DC (NE-DC) with the MgNB 104 and the Sng-eNB 106A.

[0027] Continuing to refer to FIG. 1A, CN110 communicatively connects UE102 to MBS network 170 via RAN105. MBS network 170 can provide multicast and / or broadcast services (MBS) for the UE to UE102, and MBS can be useful in many content delivery applications such as transparent IPv4 / IPv6 multicast delivery, IPTV, software delivery via wireless, group communication, IoT applications, V2X applications, and emergency messages related to public safety. For this purpose, entities operating in MBS network 170 (e.g., a server or a group of servers) support packet exchange with the UE. The packets can carry signaling (such as session initiation protocol (SIP) messages, IP messages, or other suitable messages), as well as data (or "media") such as text messages, audio, and / or video.

[0028] FIG. 1B illustrates an exemplary distributed implementation of any one or more of base stations 104, 106A, and / or 106B. In this implementation, base station 104, 106A, or 106B includes a central unit (CU) 172 and one or more distributed units (DUs) 174. CU172 includes processing hardware such as one or more general-purpose processors (e.g., CPUs), a computer-readable memory storing machine-readable instructions executable on the general-purpose processor, and / or a dedicated processing unit. For example, CU172 can include the processing hardware 130 or 140 of FIG. 1A.

[0029] Each of DU174 can also include processing hardware including one or more general-purpose processors (e.g., CPU), and a computer-readable memory storing machine-readable instructions executable on the one or more general-purpose processors, and / or a dedicated processing unit. For example, the processing hardware can include a media access control (MAC) controller configured to manage or control one or more MAC operations or procedures (e.g., random access procedures), and a radio link control (RLC) controller configured to manage or control one or more RLC operations or procedures when the base station (e.g., base station 106A) operates as an MN or SN. The processing hardware can also include a physical layer controller configured to manage or control one or more physical layer operations or procedures.

[0030] In some implementations, CU172 can include a logical node CU-CP172A that hosts the control plane portion of the packet data convergence protocol (PDCP) protocol of CU172 and / or the radio resource control (RRC) protocol of CU172. CU172 can also include a logical node CU-UP172B that hosts the user plane portion of the PDCP protocol and / or the service data adaptation protocol (SDAP) protocol of CU172. As described herein, CU-CP172A can transmit non-MBS control information and MBS control information, and CU-UP172B can transmit non-MBS data packets and MBS data packets.

[0031] CU-CP172A can be connected to a plurality of CU-UP172B through the E1 interface. CU-CP172A selects an appropriate CU-UP172B for the requested service for UE102. In some implementations, a single CU-UP172B can be connected to a plurality of CU-CP172A through the E1 interface. CU-CP172A can be connected to one or more DUs174 through the F1-C interface. CU-UP172B can be connected to one or more DUs174 through the F1-U interface under the control of the same CU-CP172A. In some implementations, one DU174 can be connected to a plurality of CU-UP172B under the control of the same CU-CP172A. In such an implementation, the connectivity between CU-UP172B and DU174 is established by CU-CP172A using the bearer context management function.

[0032] Figure 2 shows an exemplary protocol stack 200 in a simplified manner, and UE102 can communicate with an eNB / ng-eNB or gNB (e.g., one or more of base stations 104, 106A, and / or 106B) according to the protocol stack 200.

[0033] In the exemplary stack 200, the EUTRA physical layer (PHY) 202A provides a transport channel to the EUTRA MAC sublayer 204A, and the EUTRA MAC sublayer 204A provides a logical channel to the EUTRA RLC sublayer 206A. The EUTRA RLC sublayer 206A provides an RLC channel to the EUTRA PDCP sublayer 208 and, optionally, to the NR PDCP sublayer 210. Similarly, the NR PHY 202B provides a transport channel to the NR MAC sublayer 204B, and the NR MAC sublayer 204B provides a logical channel to the NR RLC sublayer 206B. The NR RLC sublayer 206B provides an RLC channel to the NR PDCP sublayer 210. The UE 102 supports both the EUTRA and NR stacks, as shown in FIG. 2, in some implementations, to support handover between the EUTRA and NR base stations and / or to support DC over the EUTRA and NR interfaces. Further, as shown in FIG. 2, the UE 102 can support the layering of the NR PDCP sublayer 210 on the EUTRA RLC sublayer 206A and the SDAP sublayer 212 on the NR PDCP sublayer 210.

[0034] The EUTRA PDCP sublayer 208 and the NR PDCP sublayer 210 receive packets, sometimes referred to as service data units (SDUs), (e.g., from an Internet Protocol (IP) layer hierarchically layered directly or indirectly on top of the PDCP sublayer 208 or 210), and output packets, sometimes referred to as protocol data units (PDUs), (e.g., to the RLC sublayer 206A or 206B). Except where the differences between SDUs and PDUs are relevant, for brevity, this disclosure refers to both SDUs and PDUs as "packets". Packets can be MBS packets or non-MBS packets. For example, MBS packets include MBS data packets containing application content for MBS services (e.g., IPv4 / IPv6 multicast delivery, IPTV, software delivery over wireless, group communication, IoT applications, V2X applications, and / or emergency messages related to public safety). In another example, MBS packets include application control information for MBS services.

[0035] On the control plane, the EUTRA PDCP sublayer 208 and the NR PDCP sublayer 210 can provide SRBs, e.g., to exchange RRC messages or non-access stratum (NAS) messages. On the user plane, the EUTRA PDCP sublayer 208 and the NR PDCP sublayer 210 can provide DRBs to support data exchange. Data exchanged on the NR PDCP sublayer 210 can be SDAP PDUs, Internet Protocol (IP) packets, or Ethernet packets.

[0036] In a scenario where UE102 operates in EN-DC with base station 104 operating as a MeNB and base station 106A operating as an SgNB, the wireless communication system 100 can provide UE102 with an MN-terminated bearer using the EUTRA PDCP sublayer 208 or an MN-terminated bearer using the NR PDCP sublayer 210. The wireless communication system 100 in various scenarios can also provide UE102 with an SN-terminated bearer using only the NR PDCP sublayer 210. The MN-terminated bearer can be an MCG bearer, a split bearer, or an MN-terminated SCG bearer. The SN-terminated bearer can be an SCG bearer, a split bearer, or an SN-terminated MCG bearer. The MN-terminated bearer can be an SRB (e.g., SRB1 or SRB2) or a DRB. The SN-terminated bearer can be an SRB or a DRB.

[0037] In some implementations, a base station (e.g., base station 104, 106A, or 106B) broadcasts MBS data packets via one or more MBS radio bearers (MRBs), and then UE 102 receives the MBS data packets via the MRBs. The base station can include the configuration of the MRBs in the multicast configuration parameters (sometimes also referred to as MBS configuration parameters) described below. In some implementations, the base station broadcasts MBS data packets via the RLC sublayer 206, MAC sublayer 204, and PHY sublayer 202, and correspondingly, UE 102 uses the PHY sublayer 202, MAC sublayer 204, and RLC sublayer 206 to receive the MBS data packets. In such implementations, the base station and UE 102 may not need to use the PDCP sublayer 208 and SDAP sublayer 212 to communicate the MBS data packets. In other implementations, the base station transmits MBS data packets via the PDCP sublayer 208, RLC sublayer 206, MAC sublayer 204, and PHY sublayer 202, and correspondingly, UE 102 uses the PHY sublayer 202, MAC sublayer 204, RLC sublayer 206, and PDCP sublayer 208 to receive the MBS data packets. In such implementations, the base station and UE 102 may not need to use the SDAP sublayer 212 to communicate the MBS data packets. In yet other implementations, the base station transmits MBS data packets via the SDAP sublayer 212, PDCP sublayer 208, RLC sublayer 206, MAC sublayer 204, and PHY sublayer 202, and correspondingly, UE 102 uses the PHY sublayer 202, MAC sublayer 204, RLC sublayer 206, PDCP sublayer 208, and SDAP sublayer 212 to receive the MBS data packets.

[0038] For simplicity of the following description, unless explicitly stated otherwise, UE 102 represents UE 102A and UE 102B.

[0039] Figures 3A - 4C are messaging diagrams of exemplary scenarios in which one or more UEs, RANs, CNs, and MBS networks implement the techniques of the present disclosure for managing MBS transmission and reception. Generally, events in the similar Figures 3A - 4C are labeled with similar reference numbers, and where differences are discussed below as necessary. Except for the differences shown in the figures and discussed below, any of the alternative implementations discussed for a particular event (e.g., for messaging and processing) may apply to the events labeled with similar reference numbers in other figures.

[0040] Referring next to scenario 300A shown in Figure 3A, UE 102 (e.g., UE 102A and / or UE 102B) first operates in an idle state (e.g., RRC_IDLE state) or an inactive state (e.g., RRC_INACTIVE state) with RAN 105 (302A). UE 102 operating in the idle or inactive state camps on cell 124 of base station 104, which includes DU 174 and CU 172. MBS network 170 sends a MBS session start message (or what is called a MBS session start request message) to CN 110 (e.g., AMF 164) to request activation of an MBS session (304). MBS network 170 includes a MBS session ID for identifying the MBS session in the MBS session start message. In some implementations, the MBS session ID is assigned by CN 110. In other implementations, the MBS session ID is assigned by MBS network 170. In some implementations, the MBS session ID can be or include a Temporary Mobile Group Identification (TMGI). In other implementations, the MBS session ID may be associated with the TMGI.

[0041] In response to the MBS session start message, CN110 can notify the UE of the activation of the MBS session. To notify the UE of the MBS session activation, CN110 generates a CN-BS inter-message including the MBS session ID and sends the CN-BS inter-message to RAN105 (306). In some implementations, the CN-BS inter-message can be an existing or new Next Generation Application Protocol (NGAP) message defined in 3GPP specification 38.413. For example, the existing NGAP message can be an NGAP paging message. In other implementations, the CN-BS inter-message can be a 6G Application Protocol (6GAP) paging message.

[0042] Upon receiving a CN-BS message (306), CU 172 extracts the MBS session ID from the CN-BS message, generates a CU-DU message including the MBS session ID, and transmits the CU-DU message to DU 174 (308). Upon receiving the CU-DU message (308), DU 174 generates one or more paging messages including the MBS session ID (310). Then, DU 174 transmits the paging message on one or more radio resources (i.e., via broadcast) on, for example, cell 124 (312). Event 312 can define an MBS session paging procedure. DU 174 can transmit the paging message on a paging control channel (PCCH). In some implementations, DU 174 can generate a DCI and a CRC of the DCI from the DCI to transmit a specific paging message among the paging messages. The DCI for transmitting the paging message may be the same or different. DU 174 scrambles the CRC with a paging radio network temporary identifier (P-RNTI). DU 174 can include a downlink allocation indicating the radio resources for transmitting the paging message in the DCI. DU 174 can transmit the DCI and the scrambled CRC on the PDCCH to UE 102 and then transmit the paging message on the indicated radio resources. When UE 102 (i.e., UE 102A and UE 102B) receives the DCI and the scrambled CRC on the PDCCH, UE 102 verifies the scrambled CRC using the P-RNTI. If UE 102 verifies that the scrambled CRC is valid, UE 102 receives or attempts to receive the paging message on the radio resources according to the DCI (312). After receiving (312) or in response to receiving the paging message, UE 102 that is in the idle state or non-active state activates (e.g., starts) receiving the MBS session identified by the MBS session ID (314).

[0043] In some implementations, DU174 transmits DCI and scrambled CRC in PDCCH monitoring occasions within paging occasions that UE102A and UE102B can receive. In some scenarios and implementations, other UEs receive DCI and scrambled CRC in paging occasions. In some implementations, the paging occasion is within a group paging DRX cycle (or what is called an MBS (paging) DRX cycle). DU174 can transmit a group paging DRX cycle configuration (referred to as an MBS paging DRX cycle configuration) that constitutes the group paging DRX cycle, for example, on cell 124 (e.g., via broadcast). In some implementations, DU174 broadcasts system information including the group paging DRX cycle configuration on the BCCH. Alternatively, DU174 can broadcast a message including the group paging DRX cycle configuration on the MCCH. Thus, UE102A and UE102B can receive the group paging DRX cycle configuration from the system information or message on the MCCH. DU174 can receive the group paging DRX cycle configuration from CU172 or an operation, administration, and maintenance (OAM) node. In other implementations, UE102A, UE102B, and CU172 receive the group paging DRX cycle configuration from CN110. For example, UE102A and UE102B can perform NAS procedures with CN110 to receive the group paging DRX cycle configuration. For example, the NAS procedure is a registration procedure. In another example, the NAS procedure is an MBS session participation procedure, an MBS session activation procedure, or an MBS-related procedure. CN110 can send the group paging DRX cycle configuration in a (306) CN-BS message sent by CN110. Then, CU172 can include the group paging DRX cycle in a (308) CU-DU message sent by CU172.

[0044] In other implementations, the paging occasion is within the first paging DRX cycle of UE102A and the second paging DRX cycle of UE102B. In some such cases, the first and second paging DRX cycles are partially or fully overlapping. When other UEs receive DCI and scrambled CRC on the paging occasion, the paging occasion is within the third paging DRX cycle of the other UEs. In such cases, the first, second, and third paging DRX cycles are partially or fully overlapping. In some implementations, UE102A, UE102B, and other UEs can derive or determine the first paging DRX cycle, the second paging DRX cycle, and the third paging DRX cycle, respectively, according to Section 7.1 of 3GPP specification 38.304. In some implementations, CU172 receives the first, second, and / or third paging DRX cycle configurations from CN110, for example, in a CN-BS message or in another CN-BS message. CU172 can determine the paging occasion from the paging DRX cycle configuration and indicate the paging occasion in a CU-DU message. In other implementations, DU174 receives the first, second, and / or third paging DRX cycle configurations from CU172, for example, in a CU-DU message or in another CU-DU message.

[0045] In some implementations, DU174 transmits DCI and scrambled CRC in a plurality of PDCCH occasions (or what is referred to as PDCCH monitoring occasions) regardless of the paging DRX cycle. In some implementations, DU174 transmits system information (e.g., via broadcast) to UE102A, UE102B, and / or other UEs for configuring a plurality of PDCCH occasions. For example, the system information can include search space configuration (e.g., pagingSearchSpace) and / or PDCCH monitoring configuration (e.g., firstPDCCH-MonitoringOccasionOfPO and nrofPDCCH-MonitoringOccasionPerSSB-InPO). Each of UE102A, UE102B, and / or other UEs monitors a specific portion of the plurality of PDCCH occasions according to the plurality of PDCCH occasions. For example, UE102A can monitor a first portion of the plurality of PDCCH occasions according to a first paging DRX cycle configuration, UE102B can monitor a second portion of the plurality of PDCCH occasions according to a second paging DRX cycle configuration, and / or other UEs can monitor a third portion of the plurality of PDCCH occasions according to a third paging DRX cycle configuration. Events 304, 306, and 308 collectively define the MBS session activation notification procedure 390.

[0046] After receiving the MBS session start message (304), the CN 110 sends (316) an MBS resource set-up request message (e.g., an MBS session resource set-up request message) to the CU 172. This message includes an MBS session ID for requesting the CU 172 to allocate resources on the air interface (e.g., Uu) between the CU 172 and the CN 110 and resources on the network interface (e.g., NG-U) for the MBS session identified by the MBS session ID. In some implementations, the CN 110 includes a QoS profile indicating QoS parameters associated with the MBS session in the MBS resource set-up request message. In some implementations, the CN 110 sends an MBS resource set-up request message in response to receiving the MBS session start message. In one implementation, the CN 110 sends an MBS resource set-up request message after sending (306) a CN-BS message. In another implementation, the CN 110 sends an MBS resource set-up request message before sending (306) a CN-BS message. In response to the MBS resource set-up request message, the CU 172 can send (322) an MBS resource set-up response message (e.g., an MBS session resource set-up response message) to the CN 110.

[0047] In response to or after receiving the MBS session resource setup message, the CU 172 may send (318) an MBS context setup request message to the DU 174 to request that the DU 174 allocate radio resources for transmitting (e.g., broadcasting or multicasting) the data of the MBS session. In response, the DU 174 allocates radio resources for transmitting (e.g., broadcasting or multicasting) the data of the MBS session and sends (320) an MBS context setup response to the CU 172 to confirm that the DU 174 has allocated radio resources for transmitting (e.g., broadcasting or multicasting) the data of the MBS session. The radio resources include time resources (e.g., time slots or OFDM symbols) and / or frequency resources (e.g., resource blocks) for one or more control channels and / or one or more data channels. In some implementations, the DU 174 broadcasts an MBS resource configuration for indicating or configuring the radio resources, e.g., on cell 124. The DU 174 may transmit one or more PDSCH transmissions including MBS data packets according to the MBS resource configuration. For example, the MBS resource configuration includes a PDCCH configuration, a search space configuration, and / or a control resource set (CORESET) configuration. The RAN 105 may send downlink control information (DCI) each having a cyclic redundancy check (CRC) scrambled by an RNTI (e.g., a group RNTI (G-RNTI) or an MBS RNTI) on the PDCCH to schedule a PDSCH transmission including an MBS data packet according to the PDCCH configuration, the search space configuration, and / or the CORESET configuration. In another example, the MBS resource configuration may include a modulation and coding scheme (MCS), a number of repetitions, and / or a hybrid automatic repeat request (HARQ) transmission scheme for broadcasting the data of the MBS session.DU174 can transmit PDSCH transmissions including MBS data packets according to configured MCS, repetition, and / or HARQ transmission schemes. In some implementations, DU174 broadcasts system information including MBS resource configuration on a broadcast control channel (BCCH), e.g., on cell 124. In other implementations, DU174 broadcasts the MBS resource configuration on a multicast control channel (MCCH), e.g., on cell 124. In some implementations, DU174 broadcasts the MBS resource configuration periodically. In further implementations, DU174 broadcasts the MBS resource configuration before or after transmitting (312) a paging message.

[0048] In some implementations, CU172 sends an MBS resource set-up response message after receiving an MBS context set-up response message. In other implementations, CU172 sends an MBS resource set-up response message before receiving an MBS context set-up response message.

[0049] CN110 can send (324) an MBS session start confirmation response message to the MBS network 170 in response to an MBS session start message. In some implementations, CN110 sends an MBS session start confirmation response message after receiving an MBS resource set-up response message. In other implementations, CN110 sends an MBS session confirmation response message to the MBS network regardless of whether it has received an MBS resource set-up response message. Events 316, 318, 320, 322 collectively define the MBS resource set-up procedure 392.

[0050] After transmitting the MBS session start message or after receiving the MBS session start confirmation response message, the MBS network 170 transmits (326) MBS data (e.g., one or more MBS data packets) of the MBS session to the CN 110, and the CN 110 transmits the MBS data to the CU 172 (328). Then, the CU 172 sends the MBS data to the DU 174 (330), and the DU 174 broadcasts the MBS data (332) using the MBS resource configuration, e.g., on cell 124, as described above.

[0051] After receiving (312) the paging message or in response to receiving it, the UE 102 in the idle state or inactive state activates (e.g., starts) (314) the reception of the MBS session identified by the MBS session ID. The UE 102 receives the MBS data (332) according to the MBS resource configuration. For example, the UE 102 receives (332) one or more PDSCH transmissions including the MBS data on the radio resources configured by the MBS configuration, decodes the PDSCH transmissions according to the MCS, and obtains the MBS data. In another example, the UE 102 receives (332) the DCI that schedules the PDSCH transmission including the MBS data according to the MBS resource configuration, decodes the PDSCH transmission according to the DCI, and obtains the MBS data. Events 326, 328, 330, and 332 collectively define the MBS data transmission procedure 394.

[0052] Figures 3B and 3C are exemplary message sequences similar to the message sequence of Figure 3A, but the UE 102 transitions from the inactive state and the idle state to the connected state, respectively.

[0053] Referring initially to FIG. 3B, in scenario 300B, UE 102 first operates in the idle state (302B). The idle UE 102 receives an MBS activation notification message (i.e., an MCCH message or a paging message) in the MBS session activation notification procedure 390. In some implementations, the MBS session ID of FIG. 3B identifies a multicast session, and the MBS session ID of FIG. 3A identifies a broadcast session.

[0054] In response to activation 314, UE 102 performs RRC connection establishment procedures with CU 172 via DU 174 (336). In response to the RRC connection establishment procedures, UE 102 transitions to a connected state (e.g., RRC_CONNECTED state) (338). To perform the RRC connection establishment procedures (336), UE 102 performs random access procedures with DU 174 (334) to synchronize with DU 174 in uplink transmission, such as when UE 102 is not synchronized with DU 174 in uplink (i.e., UE 102 does not have a valid timing advance command or value with DU 174). The random access procedures can be two-step or four-step random access procedures. To perform the RRC connection establishment procedures (336), UE 102 sends an RRC request message (e.g., RRCSetupRequest message or RRCConnectionRequest message) to CU 172 via DU 174. In some implementations where UE 102 performs two-step random access procedures (334), UE 102 sends the RRC request message in message A of the two-step random access procedures. In further implementations where UE 102 performs four-step random access procedures (334), UE 102 sends the RRC request message in message 3 of the four-step random access procedures. In some implementations where UE 102 is synchronized with DU 174 in uplink and has a configured grant configuration for the idle state, UE 102 skips or omits the random access procedures. In some such cases, UE 102 sends the RRC request message to DU 174 using the configured grant configured by the configured grant configuration. In response to the RRC request message, CU 172 can send an RRC response message (e.g., RRCSetup message or RRCConnectionSetup message) to UE 102 via DU 174.In response, UE 102 transitions to the connected state (338) and transmits an RRC completion message (e.g., an RRC Setup Complete message or an RRC Connection Setup Complete message) to CU 172 via DU 174. In some implementations, UE 102 configures a first SRB (e.g., SRB1) for communicating with CU 172 via (DU 174) in response to the RRC response message. In such implementations, UE 102 transmits the RRC completion message to CU 172 via the first SRB and DU 174. In some implementations, after transitioning to the connected state (338), UE 102 sends a service request message to CN 110 via DU 174 and CU 172. In further implementations, UE 102 includes the service request message in the RRC completion message. CU 172 extracts the service request message from the RRC completion message and sends a first BS-CN inter-message (e.g., an Initial UE Message message) including the service request message to CN 110.

[0055] After performing the RRC connection establishment procedure with UE102 (336) or after transitioning UE102 to the connected state (338), CU172 can perform a security activation procedure (e.g., RRC security mode procedure) with UE102 via DU174 to activate security (e.g., integrity protection / integrity check and / or encryption / decryption) for communication with UE102 (340). In some implementations, RAN105 sends a security activation command message (e.g., SecurityModeCommand message) to UE102, for example, via SRB and DU174, to perform the security activation procedure (430). In response, UE102 activates security (e.g., integrity protection and / or encryption) for communication with CU172 and sends a security activation complete message (e.g., SecurityModeComplete) to CU172, for example, via SRB and DU174. After activating security, CU172 can perform an RRC reconfiguration (not shown in Figure 4A) with UE102 via DU174 to configure a second SRB (e.g., SRB2) and / or a DRB for exchanging RRC messages and / or NAS messages with UE102.

[0056] After transitioning to the connected state (338) or after performing the security activation procedure (340), UE 102 can perform an MBS session participation procedure (also referred to as an MBS session activation procedure or an MBS session establishment procedure) with CN 110 via RAN 105 to indicate that UE 102 requests to participate in the MBS session. In some implementations, if UE 102 does not have an MBS context for receiving the MBS session, UE 102 decides to do so. In some cases where UE 102 has an MBS context for receiving the MBS session before receiving a message containing the MBS session ID in the MBS session activation notification procedure 390, UE 102 may skip, omit, or refrain from performing the MBS session participation procedure. To perform the MBS session participation procedure, UE 102 can send an MBS session participation request message (also referred to as an MBS session activation request message or an MBS session establishment request message) to CN 110 via DU 174 and CU 172. In response, CN 110 can send an MBS session participation acceptance message (also referred to as an MBS session activation acceptance message or an MBS session establishment acceptance message) to UE 102 via CU 172 and DU 174. In some implementations, UE 102 performs the MBS session participation procedure after activating security (340). Thus, the MBS session participation procedure is protected by security. Upon receiving an MBS session participation request message from UE 102, CU 172 sends a second BS-CN message (e.g., an uplink NAS transport message) containing the MBS session participation request message to CN 110. In other implementations, UE 102 performs the MBS session participation procedure after transitioning to the connected state (337) and before activating security. In further implementations, UE 102 includes the MBS session participation request message in the RRC completion message.CU172 extracts the MBS session participation request from the RRC completion message and sends a first BS-CN message including the MBS session participation request message to CN110. In some such implementations, UE102 determines not to send a service request message.

[0057] Alternatively, UE102 can perform the MBS session participation procedure with the MBS network 170 via CN110, CU172, and DU174 instead of CN110. In some such cases, CN110 sends the MBS session participation request message to the MBS network 170 and receives the MBS session participation acceptance message from the MBS network 170, respectively.

[0058] In some implementations, the MBS context includes the MBS session ID. In further implementations, the MBS context includes the QoS profile of the MBS session, the IP address for the MBS session, and / or one or more MRB configurations that make up one or more MRBs.

[0059] In some implementations, in response to or after receiving the first BS-CN message or the second BS-CN message, CN110 initiates the MBS resource set-up procedure (392). In response to or after receiving the MBS resource set-up request message, CU172 can perform the RRC re-configuration procedure (342) with UE102 to configure radio resources for UE102 to receive the MBS data of the MBS session (394). To perform the RRC re-configuration procedure (342), CU172 sends an RRC re-configuration message to UE102 via DU174. CU172 can include configuration parameters for UE102 to receive the MBS data of the MBS session (394) in the RRC re-configuration message. In some implementations, CU172 sets the configuration parameters according to the QoS profile. UE102 receives the MBS data in the MBS data transmission procedure 394 according to the configuration parameters. In some implementations, the configuration parameters include physical layer configuration parameters, MAC configuration parameters, RLC configuration parameters, PDCP configuration parameters, SDAP configuration parameters, and / or MRB configuration parameters. The MRB configuration parameters can configure one or more MRBs related to the MBS session. CU172 can obtain some of the configuration parameters (for example, physical layer configuration parameters, MAC configuration parameters, and / or RLC configuration parameters) from DU174 in the DU-CU message received from DU174. For example, in some implementations, the DU-CU message is an MBS context set-up response or a UE context set-up response message.

[0060] In response to the RRC reconfiguration message, UE 102 can send an RRC reconfiguration complete message to CU 172 via DU 174. In some implementations, CU 172 sends an MBS resource set setup response message to CN 110 before or after receiving the RRC reconfiguration complete message. In other implementations, CN 110 performs an MBS resource set setup procedure with RAN 105 before receiving a first BS-CN message or a second BS-CN message (392). In yet other implementations, CN 110 performs an MBS resource set setup procedure with CU 172 regardless of whether it receives a first BS-CN message or performs an MBS session participation procedure (392).

[0061] After receiving an MBS session start confirmation response message (324), MBS network 170 can perform an MBS data transmission procedure (394) to send MBS data to UE 102. If CU 172 receives MBS data from CN 110 during MBS data transmission procedure 394, CU 172 can multicast the MBS data to UE 102 via DU 174. After performing the RRC reconfiguration procedure, UE 102 uses configuration parameters for receiving MBS data from DU 174. In some implementations, CU 172 sends MBS data to UE 102 via one or more MRBs, and UE 102 receives MBS data via one or more MRBs. Events 334, 336, 338, 340, and 342 collectively define a state transition procedure 396.

[0062] Referring to FIG. 3C, scenario 300C is the same as scenario 300B, except that UE 102 initially operates in an inactive state (e.g., RRC_INACTIVE) (302C) and, in response to receiving an MBS activation notification message, UE 102 performs an RRC resume procedure with CU 172 via DU 174 instead of an RRC connection establishment procedure. In some scenarios and implementations, before UE 102 begins to operate in the inactive state (403), UE 102 was in a connected state with RAN 105. The connected UE 102 communicates data with RAN 105 via, for example, one or more radio bearers (RBs). In some implementations, the connected UE 102 communicates control plane (CP) data via one or more signaling RBs (SRBs). In some implementations, the connected UE 102 communicates user plane (UP) data via one or more data RBs (DRBs). After a certain period of data inactivity for UE 102, RAN 105 can determine that neither RAN 105 nor UE 102 has transmitted any data in the downlink or uplink direction, respectively, for a certain period of time. In response to that determination, RAN 105 can send an RRC release message (e.g., an RRCRelease message or an RRCConnectionRelease message) to UE 102 and instruct UE 102 to transition to the inactive state. UE 102 transitions to the inactive state upon receiving the RRC release message. RAN 105 can assign an I-RNTI or a resume ID to UE 102 and include the assigned value in the RRC release message. In some embodiments, after UE 102 transitions to the inactive state, UE 102 may perform one or more RAN notification area (RNA) updates with RAN 105 without a state transition.

[0063] In response to activation 314, UE 102 can perform (337) the RRC resume procedure with RAN 105. In response to the RRC resume procedure, UE 102 transitions (428) to the connected state (e.g., the RRC_CONNECTED state). In some implementations, to perform (337) the RRC resume procedure, UE 102 performs (334) a random access procedure with DU 174 to synchronize with DU 174 in uplink transmission, such as when UE 102 is not uplink synchronized with DU 174 (i.e., UE 102 does not have a valid timing advance command or value with RAN 105). The random access procedure can be a two-step or four-step random access procedure. To perform (337) the RRC resume procedure, UE 102 transmits a RRC request message (e.g., RRCResumeRequest message or RRCConnectionResumeRequest message) to CU 172 via DU 174. In some cases where UE 102 performs (334) a two-step random access procedure, UE 102 transmits the RRC request message in message A of the two-step random access procedure. In further cases where UE 102 performs (334) a four-step random access procedure, UE 102 transmits the RRC request message in message 3 of the four-step random access procedure. In further cases where UE 102 is uplink synchronized with DU 174 and has a configured grant configuration for the idle state, UE 102 skips or omits the random access procedure. In some such cases, UE 102 transmits the RRC request message using the configured grant configured by the configured grant configuration. In response to the RRC request message, CU 172 can transmit a RRC response message (e.g., RRCResume message or RRCConnectionResume message) to UE 102 via DU 174. In response, UE 102 transitions to the connected state (338) and transmits a RRC completion message (e.g., RRCResumeComplete message or RRCConnectionResumeComplete message) to RAN 105.In some implementations, a UE 102 operating in an inactive state (302C) suspends a first SRB (e.g., SRB1), a second SRB, and / or one or more DRBs. In such implementations, the UE 102 resumes the first SRB to receive an RRC response message in response to or after transmitting an RRC request message, and transmits an RRC completion message via the first SRB to the CU 172 via the DU 174. The UE 102 resumes the second SRB in response to the RRC response message. In some implementations, the UE 102 resumes one or more DRBs in response to the RRC response message, such as when the CU 172 does not indicate release of one or more DRBs in the RRC response message. In some implementations, unlike FIG. 3B, the UE 102 does not send a service request message to the CN 110 via the DU 174 and the CU 172 after transitioning to the connected state (338).

[0064] In some implementations, a UE 102 operating in an inactive state (302C) has an MBS context for an MBS session as described with respect to FIG. 3B. The UE 102 in the inactive state suspends one or more MRBs in the MBS context. In some such implementations, the UE 102 resumes one or more MRBs in response to the RRC response message, such as when the CU 172 does not indicate release of one or more MRBs in the RRC response message.

[0065] In some implementation forms, the UE 102 in the MBS data transmission procedure 394 receives MBS data for the MBS session (i.e., the first MBS session) via one or more MRBs (one, some, or all of them) that the UE 102 resumed in response to the RRC resume procedure. In such implementation forms, the UE 102 refrains from implementing the MBS session participation procedure for the active reception of the MBS session. In other implementation forms, the UE 102 implements the MBS session participation procedure, such as when the UE 102 does not have an MBS context for the MBS session. In some scenarios and implementation forms, the UE 102 has an MBS context for the second MBS session and resumes one or more MRBs for the second MBS session in response to the RRC resume procedure or the RRC response message. In such a case, the UE 102 does not receive the MBS data of the first MBS session via one or more MRBs of the MBS context for the second MBS session. Therefore, similar to event 342, the UE 102 implements the MBS session participation procedure to cause the RAN 105 to implement the RRC reconfiguration procedure in order to configure the radio resources for the UE 102 to receive the MBS data of the first MBS session. The UE 102 receives the MBS data in the MBS data transmission procedure 394 according to the configuration parameters. In some implementation forms, the configuration parameters include physical layer configuration parameters, MAC configuration parameters, RLC configuration parameters, PDCP configuration parameters, SDAP configuration parameters, and / or MRB configuration parameters. Events 334, 337, and 338 collectively define the state transition procedure 397.

[0066] Figures 4A to 4C are exemplary message sequences that are similar to the message sequences of Figures 3A to 3C, but where the DU 174 pages the UE 102A and the UE 102B in separate paging messages.

[0067] In FIG. 4A, in response to or after receiving an MBS session start message including an MBS session ID by CN110 (404), CN110 sends a first CN-BS message to CU172 (406) and sends a second CN-BS message (456) to page UE102A and UE102B, respectively. More specifically, CN110 includes the MBS session ID and the UE ID of UE102A (e.g., 5G-S-TMSI) in the first CN-BS message to page UE102A about the MBS session ID, and CN110 includes the MBS session ID and the UE ID of UE102B (e.g., 5G-S-TMSI) in the second CN-BS message to page UE102B about the MBS session ID.

[0068] In response to or after receiving the first CN-BS message, CU172 can send a first CU-DU message including the MBS session ID and the UE ID of UE102A to DU174 (408). In response to or after receiving the second CN-BS message, CU172 can send a second CU-DU message including the MBS session ID and the UE ID of UE102B to DU174 (458).

[0069] In response to or after receiving the first CU-DU message, DU174 generates (410) one or more paging messages including the MBS session ID for UE102A and transmits (412) the paging message in the first paging occasion, similar to event 312. In response to or after receiving the second CU-DU message, DU174 generates (460) one or more paging messages including the MBS session ID for UE102B and transmits (462) the paging message in the second paging occasion, similar to event 312. In some implementations, DU174 determines or derives the first paging occasion based on the UE ID of UE102A, the first paging DRX cycle configuration, the search space configuration (e.g., pagingSearchSpace), and / or the PDCCH monitoring configuration (e.g., firstPDCCH-MonitoringOccasionOfPO and nrofPDCCH-MonitoringOccasionPerSSB-InPO). Similarly, DU174 can determine or derive the second paging occasion based on the UE ID of UE102B, the second paging DRX cycle configuration, the search space configuration, and / or the PDCCH monitoring configuration. In some implementations, CU172 includes the first and second paging DRX cycle configurations in the first and second CU-DU messages, respectively.

[0070] In some implementations, the first and second paging DRX cycle configurations are the same (i.e., have the same content). In other implementations, the first and second paging DRX cycle configurations are different. In some implementations, CN110 includes the first paging DRX cycle configuration and the second paging DRX cycle configuration in the first and second CN-BS messages, respectively. In other implementations, CU172 or DU174 determines the first and second paging DRX cycle configurations, respectively, and transmits the first and second paging DRX cycle configurations to UE102A and UE102B. In some cases where the first and second paging DRX cycle configurations are the same paging DRX cycle configuration, DU174 broadcasts the paging DRX cycle configuration in the system information.

[0071] In response to or after receiving the paging message (412), UE102A in some implementations receives MBS data (432) without transitioning to the connected state, as described with respect to FIG. 3A. Similarly, in response to or after receiving the paging message (452), UE102B in some implementations receives MBS data (432) without transitioning to the connected state, as described with respect to FIG. 3A. In other implementations, in response to or after receiving the paging message (412), UE102A performs a state transition procedure similar to event 396 or 397 (496). After transitioning to the connected state, the connected UE102A receives MBS data (432). Similarly, in response to or after receiving the paging message (462), UE102B in some implementations performs a state transition procedure similar to event 396 or 397 (497). After transitioning to the connected state, the connected UE102B receives MBS data (432). Events 408, 410, 412, 458, 460, and 462 collectively define the RAN MBS session activation procedure 484.

[0072] Referring to Figure 4B, scenario 400B is the same as scenario 400A, except that CN110 sends a single CN-BS message to CU172 (407) and causes CU172 to perform the RAN MBS session activation procedure (484). In some implementations, instead of sending the first and second CN-BS messages (406, 456), CU172 performs a procedure with DU174 to page UE102A and 102B (484). CN110 can include the MBS session ID, the UE ID of UE102A, and the UE ID of UE102B in the CN-BS message. In some implementations, CN110 includes the first and second paging DRX cycle configurations in the CN-BS message. In some cases where the first and second paging DRX cycle configurations are the same, CN110 includes a single paging DRX cycle configuration (i.e., the first paging DRX cycle configuration) in the CN-BS message.

[0073] Referring to Figure 4C, scenario 400C is the same as scenario 400B, except that CU172 sends a single CU-DU message to DU174 (409) instead of sending the first and second CU-DU messages (408, 458) and causes DU174 to page UE102A and 102B. CU172 can include the MBS session ID, the UE ID of UE102A, and the UE ID of UE102B in the CU-DU message. In some implementations, CU172 includes the first and second paging DRX cycle configurations in the CU-DU message. In some cases where the first and second paging DRX cycle configurations are the same, CU172 includes a single paging DRX cycle configuration (i.e., the first paging DRX cycle configuration) in the CU-DU message.

[0074] Figures 5 to 9, Figure 13A, Figure 13B, and Figure 16 are flowcharts illustrating exemplary methods that a CU (e.g., CU 172) can implement to page a UE for MBS. Figures 10A to 12, and Figure 15 are flowcharts illustrating exemplary methods that a DU (e.g., DU 174) can implement to page a UE for MBS. Figures 14A and 14B are flowcharts illustrating exemplary methods that a base station can implement to page a UE for MBS.

[0075] Figure 5 is a flowchart of an exemplary method 500 for paging a UE for MBS. At block 502, CU 172 receives a message, such as a CN-BS message including one or more MBS session IDs, from CN 110 (e.g., events 306, 390, 406, 407). At block 504, in response to receiving the message at block 502, CU 172 generates at least one message, such as a CU-DU message including one or more session IDs (e.g., events 308, 390, 408, 458, 484, 409). In some implementations, at block 506, CU 172 includes one or more paging DRX cycle configurations in at least one message (e.g., events 308, 390, 408, 458, 484, 409). At block 508, CU 172 transmits at least one message to one or more DUs 174 to notify one or more UEs 102 to activate MBS reception (e.g., events 308, 390, 408, 458, 484, 409).

[0076] FIG. 6 is a flowchart of an exemplary method 600 for paging a UE for an MBS. At block 602, the CU 172 determines to page one or more UEs 102. At block 604, the CU 172 determines whether to page for the MBS or to page for a unicast service. If the CU 172 pages for the MBS, the flow proceeds to blocks 606, 608, and 610. At block 606, the CU 172 generates a first message, such as a CU-DU message including the MBS session ID of the MBS (e.g., events 308, 390, 408, 458, 484, 409). In some implementations, at block 608, the CU 172 includes a first paging DRX cycle configuration in the first message (e.g., events 308, 390, 408, 458, 484, 409). At block 610, the CU 172 sends the first message to at least one first DU 174 (e.g., events 308, 390, 408, 458, 484, 409). If the CU 172 pages for a unicast service (e.g., a messaging application, an email application, a streaming application, etc.), the flow proceeds to blocks 612, 614, and 616. At block 612, the CU 172 generates a second message, such as a CU-DU message including the UE ID of the UE 102. In some implementations, at block 614, the CU 172 includes a second paging DRX cycle configuration in the second message. At block 616, the CU 172 sends the second message to at least one second DU 174.

[0077] In some implementations, the first and second messages are F1AP paging messages. In other implementations, the first and second messages are, respectively, a new F1AP message (e.g., specific to the MBS) and an F1AP paging message.

[0078] In some implementations, CU172 refrains from including UE radio capabilities for paging in the first message. In other implementations, CU172 includes common UE radio capabilities for paging in the first message. The common UE radio capabilities for paging include one or more capabilities common to multiple UEs. In some implementations, CU172 includes, additionally or alternatively, UE radio capabilities for paging UE102 to be paged in a second message.

[0079] In some implementations, at least one first DU and at least one second DU can include the same DU and / or different DUs. In some implementations, the first paging DRX cycle configuration is an MBS (paging) DRX configuration or a group paging DRX cycle configuration. In further implementations, the second paging DRX cycle configuration is a UE-specific DRX cycle configuration or a DRX cycle configuration for unicast paging.

[0080] Figure 7 is a flowchart of an exemplary method 700 for paging a UE for an MBS. At block 702, CN 110 determines to send a message such as a CU-DU message. At block 704, CU 172 determines whether to send a message for the MBS session. If CU 172 sends a message for the MBS session, the flow proceeds to blocks 706, 708, and 714. If CU 172 sends a message for a service other than the MBS session (for example, if CU 172 sends a message for a unicast service such as a voice call or an Internet service (for example, a messaging application, an email application, a streaming application, etc.)), the flow proceeds to blocks 710, 712, and 714. At block 706, CN 110 includes the MBS session ID of the MBS session in the message (for example, events 308, 390, 408, 458, 484, 409). In some implementations, at block 708, CU 172 includes a first paging DRX cycle configuration in the CN-BS message (for example, events 308, 390, 408, 458, 484, 409). At block 710, CU 172 includes the ID of UE 102 (for example, 5G-S-TMSI) in the CU-DU message. In some implementations, at block 712, CU 172 includes a second paging DRX cycle configuration (for example, a non-MBS DRX configuration) in the CN-BS message. At block 714, CU 172 sends the CU-DU message to one or more DUs 174 (for example, events 308, 390, 408, 458, 484, 409).

[0081] In some implementation forms, the CU-DU message is an F1AP paging message. In further implementation forms, when CU172 decides to send a message about the MBS session, CU172 refrains from including the UE radio capabilities for paging in the message. In other implementation forms, when CU172 decides to send a message about the MBS session, CU172 includes the common UE radio capabilities for paging in the message. The common UE radio capabilities for paging include one or more capabilities common to multiple UEs.

[0082] Figure 8 is a flowchart of an exemplary method 800 for paging a UE for MBS. In block 802, CU172 receives a first message, such as a CN-BS message requesting an MBS activation notification, from CN110 (e.g., events 306, 390, 406, 407). In block 804, CU172 generates a second message, such as a CU-DU message for paging the activation notification, in response to the first message received from CN110. In block 806, CU172 determines whether the first message includes a paging DRX cycle configuration. If the first message includes a paging DRX cycle configuration, the flow proceeds to blocks 808 and 812. If the first message does not include a paging DRX cycle configuration, the flow proceeds to blocks 810 and 812. In block 808, CU172 includes the UE ID of UE102 (e.g., 5G-S-TMSI) and / or the first paging DRX cycle configuration in the second message. In block 810, CU172 includes the second paging DRX cycle configuration in the second message. In block 812, CU172 sends the second message to one or more DUs 174 (e.g., events 308, 390, 408, 458, 484, 409).

[0083] In some implementations, the first message includes one or more MBS session IDs, and CU172 includes one or more MBS session IDs in the second message. In further implementations, CU172 refrains from including UE radio capabilities for paging in the second message. In other implementations, CU172 includes common UE radio capabilities for paging in the second message. The common UE radio capabilities for paging include one or more capabilities common to a plurality of UEs.

[0084] In some implementations, the first message is an NGAP paging message. In further implementations, the first paging DRX cycle configuration is an MBS (paging) DRX configuration or a group paging DRX cycle configuration. In other implementations, the first paging DRX cycle configuration is a UE-specific DRX cycle configuration or a DRX cycle configuration for unicast paging. In some implementations, the second paging DRX cycle configuration is a RAN-specific paging DRX cycle configuration. In other implementations, the second paging DRX cycle configuration is an MBS (paging) DRX configuration or a group paging DRX cycle configuration received from an OAM node. In still other implementations, the second paging DRX cycle configuration is pre-configured in CU172.

[0085] FIG. 9 is a flowchart of an exemplary method 900 for paging a UE for MBS. At block 902, CU 172 receives a first message, such as a CN-BS message including a UE ID, from CN 110 (e.g., events 306, 390, 406, 407). At block 904, in response to receiving the first message, CU 172 determines to send a second message, such as a CU-DU message (e.g., events 308, 390, 408, 458, 484, 409). At block 906, in response to the determination, CU 172 includes the UE ID of UE 102 in the second message (e.g., events 308, 390, 408, 458, 484, 409). In some implementations, at block 908, CU 172 includes a paging DRX cycle configuration in the second message (e.g., events 308, 390, 408, 458, 484, 409). At block 910, CU 172 determines whether to page UE 102 for MBS. If CU 172 pages UE 102 for MBS, the flow proceeds to block 912. If CU 172 pages UE 102 for a service other than MBS (e.g., the unicast service described above), the flow proceeds to block 914. At block 912, CU 172 includes an MBS session ID in the second message (e.g., events 308, 390, 408, 458, 484, 409). At block 914, CU 172 sends the second message to one or more DUs 174 (e.g., events 308, 390, 408, 458, 484, 409).

[0086] Blocks in FIGS. 10A-10B that are the same are labeled with the same reference numerals.

[0087] FIG. 10A is a flowchart of an exemplary method 1000A for paging a UE for an MBS. At block 1002, the DU 174 receives a first message, such as a CU-DU message including one or more MBS session IDs, from the CU 172 (e.g., events 308, 390, 408, 458, 484, 409). In some implementations, the first message includes one or more identifiers of one or more UEs 102. At block 1004, in response to receiving the first message, the DU 174 generates a paging message including one or more session IDs (e.g., events 310, 410, 460, 484). At block 1006, the DU 174 generates a DCI and a CRC of the DCI, scrambles the CRC with a P-RNTI, and transmits the paging message (e.g., events 312, 412, 462). At block 1008, the DU 174 transmits the DCI and the scrambled CRC on the PDCCH to one or more UEs 102 at a first time instance (e.g., events 312, 412, 462). At block 1010, the DU 174 transmits the paging message to one or more UEs 102 at a second time instance later than the first time instance (e.g., events 312, 412, 462).

[0088] In some implementations, the first time instance and the second time instance can be in the same slot or different slots. For example, the first time instance includes at least one first symbol (e.g., an OFDM symbol), and the second time instance includes at least one second symbol (e.g., an OFDM symbol). The at least one first symbol and the at least one second symbol can be in the same slot or different slots.

[0089] In some implementations where the first message includes at least one DRX cycle configuration, DU174 sends DCI on PDCCH and the scrambled CRC in one or more DRX cycles configured in the DRX cycle configuration.

[0090] In some implementations where the first message includes one or more capabilities including UE radio capabilities for paging, DU174 sends DCI on PDCCH and the scrambled CRC according to the UE radio capabilities for paging.

[0091] Figure 10B is a flowchart of an exemplary method 1000B for paging a UE for MBS. In block 1002, DU174 receives a first message, such as a CU-DU message including one or more MBS session IDs, from CU172 (e.g., events 308, 390, 408, 458, 484, 409). In block 1004, in response to receiving the first message, DU174 generates a paging message including one or more session IDs for paging (e.g., events 310, 410, 460). In block 1007, DU174 generates DCI 1, ..., N (N>=1) and CRC 1, ..., N of DCI 1, ..., N, scrambles CRC 1, ..., N with P-RNTI, and transmits the paging message (e.g., events 312, 412, 462). In block 1009, DU174 transmits DCI 1, ..., N on PDCCH 1, ..., N, the scrambled CRC 1, ..., N, and the paging message to one or more UEs on cells 1, ..., N, respectively (e.g., events 312, 412, 462).

[0092] Blocks in FIGS. 11A - 11B that are the same are labeled with the same reference numerals.

[0093] FIG. 11A is a flowchart of an exemplary method 1100A for paging a UE for an MBS. At block 1102, DU 174 receives a message from CU 172, such as a CU-DU message for paging (e.g., event 308, 390, 408, 458, 484, 409). At block 1104, DU 174 determines whether the message requests paging for the MBS or requests paging for a unicast service (e.g., as described above). If the message requests paging for the MBS, the flow proceeds to blocks 1004, 1006, 1008, and 1010 of FIG. 10A. If the message requests paging for a unicast service, the flow proceeds to block 1108 and blocks 1006, 1008, and 1010 of FIG. 10A. At block 1108, in response to receiving the message, DU 174 generates a paging message that includes the UE ID of UE 102 (e.g., 5G-S-TMSI).

[0094] In some implementations, the message can be an F1AP paging message. In some implementations, at block 1110, if the message requests paging for a unicast service, DU 174 transmits the DCI, scrambled CRC, and / or paging message in one or more paging occasions in one or more paging DRX cycles of UE 102. DU 174 can refrain from transmitting the DCI, scrambled CRC, and / or paging message in the paging DRX cycles of other UEs 102 in order to conserve the power of the other UEs 102.

[0095] In other implementation forms, DU174 transmits a paging message in a paging occasion in the MBS paging DRX cycle when, for example, a message requests paging for MBS in block 1110. In yet other implementation forms, DU174 transmits a paging message over multiple paging DRX cycles of UE102 when, for example, a message requests paging for MBS in block 1110. In some implementation forms, DU174 identifies or determines that UE102 is a UE interested in receiving MBS.

[0096] Figure 11B is a flowchart of an exemplary method 1100B for paging a UE for MBS. In block 1102, DU174 receives a message, such as a CU-DU message for paging, from CU172 (e.g., events 308, 390, 408, 458, 484, 409). In block 1104, DU174 determines whether the CU-DU message requests paging for MBS or requests paging for a unicast service (e.g., as described above). If the CU-DU message requests paging for MBS, the flow proceeds to block 1107. If the CU-DU message requests paging for a unicast service, the flow proceeds to block 1109. In block 1107, DU174 transmits a first paging message in a first paging DRX cycle in response to receiving the CU-DU message (e.g., events 312, 412, 462). In block 1109, DU174 transmits a second paging message in a second paging DRX cycle in response to receiving the CU-DU message.

[0097] The first and second paging DRX cycles can be similar to the examples and implementation forms described with respect to FIG. 8. Thus, the specific implementation forms for FIG. 8, when relevant, also apply to FIGS. 11A and 11B.

[0098] Figure 12 is a flowchart of an exemplary method 1200 for paging a UE for MBS. In block 1202, DU 174 receives a first message, such as a CU-DU message requesting an MBS activation notification, from CU 172 (e.g., events 308, 390, 408, 458, 484, 409). In block 1204, DU 174 generates a paging message including one or more MBS session IDs in response to the first message (e.g., events 312, 412, 462). In block 1206, DU 174 determines whether the first message includes a paging DRX cycle. If the first message includes a paging DRX cycle, the flow proceeds to block 1208. If the first message does not include a paging DRX cycle, the flow proceeds to block 1210. In block 1208, DU 174 transmits the paging message in the first paging DRX cycle. In block 1210, DU 174 transmits the paging message in the second paging DRX cycle.

[0099] The first and second paging DRX cycles can be the same as the examples and implementations described with respect to FIG. 8. Accordingly, the specific implementations with respect to FIG. 8 are also applicable to FIG. 12, where relevant.

[0100] In some implementations, the first message is an F1AP paging message. In further implementations, to send a paging message, DU174 generates a DCI and a CRC of the DCI, and scrambles the CRC with a P-RNTI. DU174 transmits, in block 1208, the DCI, the scrambled CRC, and / or the paging message in the on-duration (e.g., a paging occasion) of a first DRX cycle (e.g., a paging DRX cycle or a unicast paging DRX cycle) for one or more paging occasions. In other implementations, DU174 refrains from transmitting, in block 1208, the DCI, the scrambled CRC, and / or the paging message in the paging DRX cycle of other UEs in order to save the power of other UEs.

[0101] In other implementations, DU174 transmits, in block 1210, the DCI, the scrambled CRC, and / or the paging message in the on-duration of a second DRX cycle (e.g., an MBS DRX cycle or an MBS paging DRX cycle). In yet other implementations, DU174 transmits the paging message over multiple DRX cycles of UE102 in block 1210. In some implementations, DU174 identifies or determines that UE102 is a UE interested in receiving MBS.

[0102] Figure 13 is a flowchart of an exemplary method 1300 for paging a UE for MBS. At block 1302, the CU 172 receives a first message, such as a CN-BS message including UE paging identification information, from the CN 110 (e.g., events 306, 390, 406, 407). At block 1304, the CU 172 determines to send a second message to the DU 174 in response to the first message (e.g., events 308, 390, 408, 458, 484, 409). At block 1306, the CU 172 determines whether the UE paging identification information is a CN ID or an MBS session ID. If the UE paging identification information is a CN ID (e.g., 5G-S-TMSI), the flow proceeds to blocks 1308 and 1312. If the UE paging identification information is an MBS session ID, the flow proceeds to blocks 1310 and 1312. At block 1308, the CU 172 includes the CN ID in the second message (e.g., events 308, 390, 408, 458, 484, 409). At block 1310, the CU 172 includes the MBS session ID in the second message (e.g., events 308, 390, 408, 458, 484, 409). At block 1312, the CU 172 sends the second message to one or more DUs 174.

[0103] In some implementations, the first message is an NGAP paging message or an interface message for 6G (e.g., a 6G Application Protocol (6GAP) message). In further implementations, the second message is an F1AP paging message indicating to one or more DUs 174 to page one or more UEs 102. For example, the second message can be a paging message defined in 3GPP specification 38.473.

[0104] In some implementations, CU172 determines that the UE paging identification information is the MBS session ID when the first message includes an indication indicating that the UE paging identification information is the MBS session ID. When the first message does not include that indication, CU172 can determine that the UE paging identification information is the CN ID.

[0105] In some implementations, CU172 includes the MBS session ID or the CN ID in the UE paging identification information IE of the second message. In some such cases, CU172 includes an indication indicating that the UE paging identification information is the MBS session ID in the second message, such as when CU172 determines that the UE paging identification information is the MBS session ID. CU172 can exclude an indication indicating that the UE paging identification information is the CN ID in the second message, such as when CU172 determines that the UE paging identification information is the CN ID.

[0106] Blocks that are the same in FIGS. 14A - 14B are labeled with the same reference numerals.

[0107] FIG. 14A is a flowchart of an exemplary method 1400A for paging a UE for an MBS. At block 1402, a RAN (e.g., RAN 105) receives a first message from the CN 110, such as a CN-BS message including a UE ID, a paging DRX cycle configuration, and an MBS session ID (e.g., events 406, 407). At block 1404, RAN 105 determines a paging occasion according to the UE ID and the paging DRX cycle configuration. At block 1406, RAN 105 generates a paging message including the UE ID and the MBS session ID (e.g., events 410, 460). At block 1408, RAN 105 generates DCI for transmitting the paging message. At block 1410, RAN 105 transmits the DCI on the PDCCH on one or more cells at the paging occasion (e.g., events 412, 462). At block 1412, RAN 105 transmits the paging message on one or more cells (e.g., events 412, 462).

[0108] In some implementations, RAN 105 refrains from including the UE ID in the paging message. Alternatively, RAN 105 includes the UE ID in the paging message.

[0109] Figure 14B is a flowchart of an exemplary method 1400B for paging a UE for an MBS. At block 1402, the RAN 105 receives a first message from the CN 110, such as a CN-BS message including a UE ID, a paging DRX cycle configuration, and an MBS session ID. At block 1405, the RAN 105 determines a paging occasion according to the MBS session ID and the paging DRX cycle configuration. At block 1406, the RAN 105 generates a paging message including the UE ID and the MBS session ID. At block 1408, the RAN 105 generates DCI for transmitting the paging message. At block 1410, the RAN 105 transmits the DCI on the PDCCH on one or more cells at the paging occasion. At block 1412, the RAN transmits the paging message on one or more cells.

[0110] FIG. 15 is a flowchart of an exemplary method 1500 for managing paging for multicast and broadcast services implemented at a DU. At block 1502, the DU 174 receives, from the CU 172, an identifier of an MBS session and an identifier of the UE 102 (e.g., events 308, 408, 409, and 458 and blocks 1002, 1102, and 1202 of FIGS. 3A-4C and 10A-12). At block 1504, when one or more radio connections between the UE 102 and the DU 174 are inactive, the DU 174 transmits to the UE 102 corresponding to the identifier, one or more paging messages including the identifier of the MBS session (e.g., events 312, 412, and 462 and blocks 1004 / 1010, 1106 / 1107 / 1108 / 1109 / 1110, and 1204 / 1208 / 1210 of FIGS. 3A-4C and 10-12). At block 1506, following the transmission, the DU 174 broadcasts to the UE 102 one or more MBS data packets according to one or more MBS resource configurations (e.g., events 332, 431, and 432 of FIGS. 3A-4C).

[0111] FIG. 16 is a flow diagram of an exemplary method 1600 for managing paging for multicast and broadcast services implemented at a CU. At block 1602, the CU 172 receives from the CN 110 an identifier of an MBS session and an identifier of the UE 102 (e.g., events 306, 406, and 456 and blocks 502, 802, 902, and 1302 of FIGS. 3A-5, 8, 9, and 13). At block 1604, the CU 172 transmits to the DU 174 one or more messages including the identifier of the MBS session and the identifier of the UE 102 (e.g., events 308, 408, 409, and 458 and blocks 504 / 508, 606 / 610, 612 / 616, 706 / 710 / 714, 808 / 812, 906 / 912 / 914, and 1310 / 1312 of FIGS. 3A-9 and 13). At block 1606, the CU 172 transmits to the DU 174 one or more parameters for paging associated with the MBS session (e.g., events 318, 408, 409, and 458 and blocks 506 / 508, 608 / 610, 614 / 616, 708 / 712 / 714, 810 / 812, 908 / 914, 1308 / 1312). At block 1608, the CU 172 transmits to the DU 174 one or more MBS data packets to be broadcast to the UE 102 according to one or more parameters (e.g., events 330 / 430 of FIGS. 3A-4C).

[0112] The following list of examples reflects various embodiments explicitly contemplated by the present disclosure.

[0113] Example 1. A method for managing paging for multicast and broadcast services (MBS), the method being implemented in a central unit (CU) of a distributed base station, the method comprising, in the CU, receiving from a core network (CN) an identifier of an MBS session and an identifier of a user equipment (UE); transmitting to a distributed unit (DU) of the distributed base station: (i) the identifier of the MBS session, (ii) the identifier of the UE, and (iii) one or more parameters for paging associated with the MBS session; and transmitting to the DU one or more MBS data packets to be broadcast to the UE according to the one or more parameters.

[0114] Example 2. The method of Example 1, further comprising receiving from the CN a message comprising at least an identifier of an MBS session and one or more parameters for paging; generating one or more MBS resource configurations based on the at least one or more parameters for paging; and transmitting the one or more MBS resource configurations to the DU.

[0115] Example 3. The method of Example 1, further comprising transmitting to each of a plurality of UEs a respective message comprising an identifier of an MBS session and an identifier of the respective UE of the plurality of UEs.

[0116] Example 4. The method of Example 1, further comprising transmitting to a plurality of UEs a shared message comprising an identifier of an MBS session and a list of identifiers of the respective UEs of the plurality of UEs.

[0117] Example 5. The method of Example 3 or 4, further comprising receiving from the CN a plurality of CN messages, each of the plurality of CN messages comprising an identifier of an MBS session and an identifier of the respective UE of the plurality of UEs.

[0118] The method of Example 3 or 4, further comprising receiving, from CN, a shared CN message including an identifier of an MBS session and a list of identifiers of each of a plurality of UEs.

[0119] The method of any one of Examples 1 to 6, wherein the step of transmitting an identifier of an MBS session is in response to a decision by the DU to page the UE for the MBS session.

[0120] The method of any one of Examples 1 to 7, wherein one or more parameters include at least one of a paging cycle configuration of an MBS session or a paging cycle configuration of one or more UEs.

[0121] The method of Example 8, further comprising determining a paging period according to at least one of a paging cycle configuration and an identifier of the UE or an identifier of the MBS session, generating a paging message including the identifier of the MBS session and the identifier of the UE, and transmitting information about the paging period and the paging message to the DU.

[0122] A method for managing paging for multicast and broadcast services (MBS), the method being implemented in a distributed unit (DU) of a distributed base station, and receiving, from a central unit (CU) of the distributed base station, an identifier of an MBS session and an identifier of a user equipment (UE), transmitting to the UE a paging message including the identifier of the MBS session, and, following the transmitting step, broadcasting to the UE one or more MBS data packets according to one or more MBS resource configurations.

[0123] The method of Example 10, wherein the step of transmitting the paging message is according to at least one of a paging cycle configuration of the MBS session or a paging cycle configuration of the UE.

[0124] Example 12. The method of Example 10, further comprising the step of transmitting, for each of a plurality of UEs, a respective paging message including an identifier of an MBS session.

[0125] Example 13. The method of Example 12, wherein the step of transmitting a paging message includes transmitting a first subset of paging messages according to a paging cycle of an MBS session and transmitting a second subset of paging messages according to a respective paging cycle of corresponding UEs among the plurality of UEs.

[0126] Example 14. The method according to any one of Examples 10 to 13, wherein the identifier of the MBS session includes temporary mobile group identifier information (TMGI).

[0127] Example 15. An apparatus comprising processing hardware and configured to implement the method according to any one of Examples 1 to 14.

[0128] Example 16. The method of Example 10, further comprising the step of broadcasting one or more MBS resource configurations to a UE using an identifier of an MBS session, wherein the step of broadcasting one or more MBS data packets follows the step of broadcasting one or more MBS resource configurations.

[0129] Example 17. The method of Example 11, wherein the step of receiving an identifier of an MBS session and an identifier of a UE includes receiving a message from a CU, the message including an identifier of a first UE and an identifier of a second UE.

[0130] Example 18. The method of Example 11, wherein the step of receiving an identifier of an MBS session and an identifier of a UE includes receiving a first message from a CU including an identifier of a first UE and receiving a second message from a CU including an identifier of a second UE.

[0131] Example 19. The method of Example 10, wherein the UE is the first UE among a plurality of UEs, and the step of transmitting one or more paging messages includes transmitting a first paging message among the one or more paging messages to the first UE according to the paging cycle of the first UE, and transmitting a second paging message among the one or more paging messages to the second UE according to the paging cycle of the second UE.

[0132] Example 20. The method of Example 10, further comprising generating a downlink control information set and a cyclic error checking algorithm, generating a secured error checking algorithm by applying a security protocol to the cyclic error checking algorithm, and transmitting the downlink control information and the secured error checking algorithm to the UE.

[0133] Example 21. The method of Example 20, wherein the DU transmits the downlink control information and the secured error checking algorithm to the UE during a first paging period, and transmits a paging message to the UE during a second paging period.

[0134] Example 22. The method of Example 20 or 21, wherein the UE is the first UE among a plurality of UEs, the downlink control information is a plurality of downlink control information sets, the cyclic error checking algorithm is a plurality of cyclic error checking algorithms equal in number to the plurality of downlink control information sets, and the step of transmitting a paging message to the first UE is via a plurality of cells equal in number to the plurality of downlink control information sets.

[0135] Example 23. The method of Example 10 further includes receiving, from the CU, a paging message, and determining whether to generate a first paging message for the UE including an identifier of an MBS session or to generate a second paging message for the UE including an identifier of the UE based on whether the paging message requests an MBS or requests a unicast service.

[0136] Example 24. The method of Example 10 further includes receiving, from the CU, a paging message, and determining whether to transmit a first paging message according to the paging cycle configuration of the MBS session or to transmit a second paging message according to the paging cycle configuration of the UE based on whether the paging message requests an MBS or requests a unicast service.

[0137] Example 25. The method of Example 10 further includes receiving, from the CU, a message requesting activation of an MBS session, and determining whether to transmit a paging message to the DU according to a first paging cycle configuration or to transmit it according to a second paging cycle configuration based on whether the message requesting activation includes a first paging cycle configuration.

[0138] Example 26. The method of Example 1 further includes determining that the first DU pages for a service, and determining whether to transmit a first message including an MBS session identifier to the first DU or to transmit a second message including a UE identifier of the UE to a second DU based on whether the service is an MBS service or a unicast service.

[0139] Example 27. The method of Example 26 further includes including an MBS paging cycle configuration in the first message in the first message.

[0140] The method of Example 26, further comprising the step of including in the second message the UE paging cycle configuration of the UE in the second message.

[0141] Example 29. The method of Example 1, further comprising the steps of receiving a first message from the CN that includes a request to activate an MBS session, generating a second message to be sent to the DU to activate the MBS session, and determining whether to include the identifier of the UE in the second message based on whether the first message includes a paging cycle configuration.

[0142] Example 30. The method of Example 29, further comprising the step of determining whether to include the first paging cycle configuration or the second paging cycle configuration in the second message based on whether the paging cycle configuration is the first paging cycle configuration and whether the first message includes the first paging cycle configuration.

[0143] Example 31. The method of Example 1, further comprising the steps of receiving a message from the CN that includes UE paging identification information, and determining whether to send a message that includes the identifier of the CN or a message that includes the identifier of the MBS session based on whether the UE paging identification information is the identifier of the CN or the identifier of the MBS session.

[0144] Example 32. The method of Example 31, wherein the UE paging identification information is the identifier of the CN when the message that includes the UE paging identification information includes an indication that the UE paging identification information is the identifier of the MBS session, and the UE paging identification information is the identifier of the MBS session when the message that includes the UE paging identification information does not include an indication that the UE paging identification information is the identifier of the MBS session.

[0145] Example 33. An apparatus comprising processing hardware and configured to implement the method according to any one of Examples 16 to 32.

[0146] The following additional considerations apply to the above discussion.

[0147] In some implementations, the UE can receive MBS data in a broadcast session without performing the session participation procedure for receiving MBS. That is, the UE does not need to perform the session participation procedure for the broadcast session. In other implementations, the UE can receive MBS data in a broadcast session according to configuration parameters broadcast by the RAN, that is, without performing the RRC reconfiguration procedure for receiving the configuration parameters for receiving MBS data.

[0148] In some implementations, the UE must perform the session participation procedure to receive MBS data in a multicast session. In other implementations, the UE can receive MBS data in a multicast session only according to the configuration parameters received in the RRC reconfiguration message.

[0149] In some implementations, "MBS" can be replaced by "MBS session" and vice versa. In some implementations, "message" is used and can be replaced by "information element (IE)". In some implementations, "IE" is used and can be replaced by "field". In some implementations, the singular form "configuration" can be replaced by the plural form "configurations" or configuration parameters. In some implementations, the singular form "MBS session ID" can be replaced by the plural form "MBS session IDs", and the singular form "MBS session" can be replaced by the plural form "MBS sessions".

[0150] A user device (e.g., UE102) on which the techniques of the present disclosure can be implemented can be any suitable device capable of wireless communication, such as a smartphone, a tablet computer, a laptop computer, a mobile game console, a point-of-sale (POS) terminal, a health monitoring device, a drone, a camera, a media streaming dongle or another personal media device, a wearable device such as a smartwatch, a wireless hotspot, a femtocell, or a broadband router. Further, in some cases, the user device may be embedded in an electronic system such as a vehicle or a head unit of an advanced driver assistance system (ADAS). Still further, the user device can operate as an Internet of Things (IoT) device or a mobile Internet device (MID). Depending on the type, the user device can include one or more general-purpose processors, computer-readable memory, a user interface, one or more network interfaces, one or more sensors, and the like.

[0151] Certain embodiments are described in this disclosure as including a logic circuit or several components or modules. A module may be a software module (e.g., code stored on a non-transitory machine-readable medium) or a hardware module. A hardware module is a tangible unit capable of performing a particular operation and may be configured or arranged in a particular way. A hardware module can include a dedicated circuit or logic circuit that is permanently configured (e.g., as a dedicated processor such as a field programmable gate array (FPGA) or an application specific integrated circuit (ASIC)) to perform a particular operation. A hardware module may also include a programmable logic circuit or circuit that is temporarily configured by software (e.g., included within a general-purpose processor or other programmable processor) to perform a particular operation. The decision to implement a hardware module in a dedicated permanently configured circuit or in a temporarily configured (e.g., configured by software) circuit can be caused by cost and time considerations.

[0152] When implemented in software, the techniques can be provided as part of an operating system, a library used by multiple applications, a particular software application, etc. The software can be executed by one or more general-purpose processors or one or more dedicated processors.

Description of Reference Numerals

[0153] 100 Wireless communication system 102 UE 102A UE 102B UE 104 Base station, MeNB, Mng-eNB, MgNB 106 Base station 106A Base station, SgNB, Sng-eNB 106B Base station 105 RAN 110 Core Network (CN), CN 111 Evolved Packet Core (EPC), EPC 112 Serving Gateway (SGW), SGW 114 Mobility Management Entity (MME), MME 116 Packet Data Network Gateway (PGW), PGW 124 Cell 126A Cell 126B Cell 130 Processing Hardware 132 Base Station MBS Controller 134 Base Station Non-MBS Controller 136 RRC Controller 138 Paging Controller 140 Processing Hardware 142 Base Station MBS Controller 144 Base Station Non-MBS Controller 146 RRC Controller 148 Paging Controller 150 Processing Hardware 152 UE MBS Controller 154 UE Non-MBS Controller 156 RRC Controller 158 UE Paging Controller 160 5th Generation Core (5GC), 5GC 162 User Plane Function (UPF), UPF 164 Access and Mobility Management (AMF), AMF 166 Session Management Function (SMF), SMF 170 MBS Network 172 Central Unit (CU), CU 172A Logical Node CU-CP, CU-CP 172B Logical Node CU-UP, CU-UP 174 Distributed Unit (DU), DU 200 Protocol Stack, Stack 202A Physical Layer (PHY) 202B NR PHY 204A EUTRA MAC Sub - layer 204B NR MAC Sub - layer 206A EUTRA RLC Sub - layer, RLC Sub - layer 206B NR RLC Sub - layer, RLC Sub - layer 208 EUTRA PDCP Sub - layer, PDCP Sub - layer 210 NR PDCP Sub - layer, PDCP Sub - layer 212 SDAP Sub - layer 300A Scenario 300B Scenario 300C Scenario 390 MBS Session Activation Notification Procedure 392 MBS Resource Set - up Procedure 394 MBS Data Transmission Procedure 396 State Transition Procedure 397 State Transition Procedure 400A Scenario 400B Scenario 400C Scenario 484 RAN MBS Session Activation Procedure 500 Method 600 Method 700 Method 800 Method 900 Method 1000A Method 1000B Method 1100A Method 1100B Method 1200 Method 1300 Method 1400A Method 1400B Method 1500 Method 1600 Method

Claims

1. A method for managing paging for multicast and broadcast services (MBS), the method being implemented in a central unit (CU) of a distributed base station, in the CU, receiving, from a core network (CN), an identifier of an MBS session and an identifier of a user equipment (UE), wherein the MBS session is identifiable based on the identifier of the MBS session, transmitting to a distributed unit (DU) of the distributed base station: (i) the identifier of the MBS session, (ii) the identifier of the UE, and (iii) one or more parameters for paging associated with the MBS session, including a paging cycle configuration of the MBS session, the paging cycle configuration of the MBS session having one or more parameters including a paging occasion on which a paging message is to be broadcast, during the MBS session, transmitting to the DU one or more MBS data packets in the paging message to be broadcast to the UE according to the one or more parameters comprising the method.

2. receiving, from the CN, a message including at least the identifier of the MBS session and the one or more parameters for paging, generating one or more MBS resource configurations based on at least the one or more parameters for paging, transmitting the one or more MBS resource configurations to the DU further comprising the method according to Claim 1.

3. transmitting, to each of a plurality of UEs, a respective message including the identifier of the MBS session and the respective identifier of the UE among the plurality of UEs further comprising the method according to Claim 1.

4. transmitting, to a plurality of UEs, a shared message including the identifier of the MBS session and a list of the respective identifiers of the plurality of UEs further comprising the method according to Claim 1.

5. Receiving, from the CN, a plurality of CN messages, each of the plurality of CN messages including the identifier of the MBS session and the identifier of each of the UEs among the plurality of UEs The method according to claim 3, further comprising: **Claim 6** Receiving, from the CN, a plurality of CN messages, each of the plurality of CN messages including the identifier of the MBS session and the identifier of each of the UEs among the plurality of UEs The method according to claim 4, further comprising: **Claim 7** Receiving, from the CN, a shared CN message including the identifier of the MBS session and a list of the identifiers of each of the plurality of UEs The method according to claim 3, further comprising: **Claim 8** Receiving, from the CN, a shared CN message including the identifier of the MBS session and a list of the identifiers of each of the plurality of UEs The method according to claim 4, further comprising: **Claim 9** The method according to claim 1, wherein the step of transmitting the identifier of the MBS session is in response to a determination by the DU to page the UE about the MBS session **Claim 10** Determining a paging period according to at least one of the paging cycle configuration and the identifier of the UE or the identifier of the MBS session; Generating a paging message including the identifier of the MBS session and the identifier of the UE; and Transmitting information about the paging period and the paging message to the DU The method according to claim 1, further comprising: **Claim 11** A method for managing paging for a multicast and broadcast service (MBS), the method being implemented in a distributed unit (DU) of a distributed base station Receiving, from a central unit (CU) of the distributed base station, an identifier of the MBS session, an identifier of a user equipment (UE), and one or more parameters for paging associated with the MBS session, the one or more parameters including a paging cycle configuration of the MBS session, the paging cycle configuration of the MBS session having a paging occasion in which a paging message is to be broadcast; Transmitting, to the UE, a paging message including the identifier of the MBS session in the paging occasion; After the transmitting step, broadcasting, to the UE, one or more MBS data packets according to one or more MBS resource configurations during the MBS session identifiable based on the identifier of the MBS session; A method comprising.

12. The method according to claim 11, further comprising transmitting, for each of a plurality of UEs, a respective paging message including the identifier of the MBS session. The method according to claim 11, further comprising.

13. The step of transmitting the paging message comprises: Transmitting a first subset of the paging messages according to a paging cycle of the MBS session; Transmitting a second subset of the paging messages according to a respective paging cycle of corresponding UEs among the plurality of UEs. The method according to claim 12, comprising.

14. The method according to claim 11, wherein the identifier of the MBS session includes temporary mobile group identification information (TMGI).

15. An apparatus comprising processing hardware and configured to implement the method according to any one of claims 1 to 14.

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