Method and apparatus for multicast and broadcast services

Abstract

The present disclosure relates to methods and apparatus for multicast and broadcast services. A method for handing over a user equipment (UE) from a first NodeB to a second NodeB, performed by the first NodeB, comprises: transmitting at least one first data packet to the UE; and receiving an alignment indication from a core network.

Description

Technical Field

[0001] Embodiments of the present disclosure relate generally to wireless communication technologies, and more particularly to methods and apparatus for multicast and broadcast services (MBS). Background Art

[0002] In New Radio (NR) Rel-17, the MBS initiative focuses on small-area mixed-mode multicast (also referred to as Objective A in TR 23.757). The goal is to enable universal MBS services within the 5G System (5GS) and identify use cases that can benefit from this feature. These use cases include, but are not limited to: public safety and mission-critical applications, vehicle-to-everything (V2X) applications, transparent Internet Protocol version 4 (IPv4) / Internet Protocol version 6 (IPv6) multicast delivery, Internet Protocol television (IPTV), wireless software delivery, group communications, and Internet of Things (IoT) applications. In these use cases, service continuity and reliability are highly demanding. Summary of the Invention

[0003] Some embodiments of the present disclosure at least provide technical solutions for multicast and broadcast services.

[0004] Some embodiments of the present disclosure provide a method for handing over a user equipment (UE) from a first NodeB to a second NodeB, performed by the first NodeB. The method may include: transmitting at least one first data packet; and receiving an alignment indication from a core network.

[0005] Some other embodiments of the present disclosure provide a method for handing over a user equipment (UE) from a first NodeB to a second NodeB, performed by the second NodeB. The method may include: receiving a handover message from the first NodeB; and transmitting a plurality of data packets to the UE based on an alignment indication.

[0006] Some other embodiments of the present disclosure provide a method for handover from a first NodeB to a second NodeB, performed by a network entity. The method may include: transmitting a plurality of data packets of a traffic flow via a GTP-U tunnel shared with the first NodeB; transmitting the plurality of data packets of the traffic flow via a GTP-U tunnel shared with the second NodeB; receiving a path switch indication message from the second NodeB indicating the handover from the first NodeB to the second NodeB; and sending an alignment indication transmission to the first NodeB.

[0007] Some other embodiments of the present disclosure provide a method for handing over a user equipment (UE) from a first NodeB to a second NodeB, performed by the UE, wherein the method may include: receiving at least one first data packet from the second NodeB via a unicast bearer; and receiving at least one second data packet from the second NodeB; wherein the at least one first data packet is forwarded from the first NodeB.

[0008] Some other embodiments of the present disclosure provide a method performed by an anchor NodeB. The method may include: receiving a data packet from a core network; and assigning a sequence number to the data packet.

[0009] Some other embodiments of the present disclosure provide a method performed by a NodeB. The method may include: receiving an anchor indication message indicating an anchor NodeB; and receiving a sequence number of a data packet of a multicast or broadcast service from the anchor NodeB.

[0010] Some embodiments of the present disclosure also provide an apparatus comprising: at least one non-transitory computer-readable medium having computer-executable instructions stored therein; at least one receiver; at least one transmitter; and at least one processor coupled to the at least one non-transitory computer-readable medium, the at least one receiver, and the at least one transmitter. The computer-executable instructions are programmed to implement any of the methods described above with the at least one receiver, the at least one transmitter, and the at least one processor.

[0011] Embodiments of the present disclosure provide technical solutions for multicast and broadcast services. Therefore, embodiments of the present disclosure can provide lossless data transmission during handover between gNodeBs (gNBs). BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to illustrate the manner in which the advantages and features of the present application can be obtained, the description of the present application is presented by reference to specific embodiments of the present application shown in the accompanying drawings. These drawings depict only example embodiments of the present application and therefore should not be considered limiting of its scope.

[0013] Figure 1 is a schematic diagram illustrating an exemplary wireless communication system according to some embodiments of the present disclosure;

[0014] Figure 2 is a flow chart illustrating a method for MBS with a handover procedure according to some embodiments of the present disclosure;

[0015] Figure 3 A flowchart illustrating a method for MBS with smooth handover according to some embodiments of the present disclosure is shown;

[0016] Figure 4 shows a flowchart illustrating a method for MBS with count value alignment according to some embodiments of the present disclosure;

[0017] Figure 5 shows a flowchart illustrating a method for MBS with count value alignment according to some embodiments of the present disclosure;

[0018] Figure 6 shows a flowchart illustrating a method for MBS with count value alignment according to some embodiments of the present disclosure;

[0019] Figure 7 is a flowchart illustrating a method for MBS according to some embodiments of the present disclosure;

[0020] Figure 8 is a flowchart illustrating a method for MBS according to some embodiments of the present disclosure;

[0021] Figure 9 is a flowchart illustrating a method for MBS according to some embodiments of the present disclosure;

[0022] Figure 10 is a flowchart illustrating a method for MBS according to some embodiments of the present disclosure;

[0023] Figure 11 is a flowchart illustrating a method for MBS according to some embodiments of the present disclosure;

[0024] Figure 12 is a flowchart illustrating a method for MBS according to some embodiments of the present disclosure;

[0025] Figure 13 A simplified block diagram illustrating a device for MBS according to some embodiments of the present disclosure;

[0026] Figure 14 A simplified block diagram illustrating an apparatus for MBS according to some embodiments of the present disclosure; and

[0027] Figure 15 A simplified block diagram illustrating a device for MBS according to some embodiments of the present disclosure is shown. DETAILED DESCRIPTION

[0028] The detailed description of the accompanying drawings is intended as a description of the presently preferred embodiments of the present disclosure and is not intended to represent the only form in which the present disclosure can be practiced. It should be understood that the same or equivalent functions can be accomplished by different embodiments that are intended to be encompassed within the spirit and scope of the present disclosure.

[0029] Reference will now be made in detail to certain embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings. To facilitate understanding, the embodiments are provided in the context of specific network architectures and new service scenarios (e.g., 3GPP 5G, New Radio (NR), 3GPP LTE Release 8, etc.). Those skilled in the art will appreciate that as network architectures and new service scenarios evolve, the embodiments of the present disclosure will also be applicable to similar technical problems.

[0030] Figure 1 is a schematic diagram illustrating an exemplary wireless communication system 10 according to an embodiment of the present disclosure.

[0031] like Figure 1 As shown in FIG, the wireless communication system 10 may include at least one core network, at least one base station, and at least one UE. The wireless communication system 10 is compatible with any type of network capable of sending and receiving wireless communication signals. For example, the wireless communication system 10 is compatible with a wireless communication network, a cellular telephone network, a time division multiple access (TDMA)-based network, a code division multiple access (CDMA)-based network, an orthogonal frequency division multiple access (OFDMA)-based network, an LTE network, a 3GPP-based network, a 3GPP 5G NR network, a satellite communication network, a high altitude platform network, and / or other communication networks.

[0032] A base station may be referred to as a base unit, base, access point, access terminal, macro cell, Node-B, enhanced Node B (eNB), gNB, home Node-B, relay node, device, remote unit, or any other term used in the art. Base stations may be distributed across a geographic area. Generally speaking, a base station is part of a radio access network that may include one or more controllers communicatively coupled to one or more corresponding base stations.

[0033] The base stations are typically communicatively coupled to one or more packet core networks (PCNs), which can be coupled to other networks, such as packet data networks (PDNs) (e.g., the Internet) and public switched telephone networks, among other networks. These and other elements of the radio access network and core network are not shown, but are generally well known to those of ordinary skill in the art. For example, one or more base stations can be communicatively coupled to a mobility management entity (MME), a serving gateway (SGW), and / or a packet data network gateway (PGW). For example, one or more base stations can be communicatively coupled to an access and mobility management function (AMF), a user plane function (UPF), and / or a session management function (SMF) in the 5G core network.

[0034] The embodiments of the present disclosure may be provided in a network architecture that adopts various service scenarios, such as, but not limited to, 3GPP 3G, Long Term Evolution (LTE), LTE-Advanced (LTE-A), 3GPP 4G, 3GPP 5G NR (New Radio), 3GPP LTE Release 12 and above, etc. It is contemplated that as 3GPP and related communication technologies develop, the terms used in this application may change, which should not affect the principles of this application.

[0035] Specifically, for illustrative purposes, the wireless communication system 10 includes one core network 101, two gNBs 102, 103, and four UEs 104 to 107. Figure 1 A specific number of core networks, gNBs, and UEs are depicted in FIG, but it is contemplated that any number of core networks, gNBs, and UEs may be included in the wireless communication system 10.

[0036] The core network in communication system 10 may be a 5G core network interconnecting a wide area network (e.g., an Internet Protocol (IP) service network) and radio access network nodes (e.g., eLTE enhanced Node B (eNB) radio access network nodes, 5G gNB radio access network nodes, and gNBs 102 and 103). The core network may be one or more devices or services between the wide area network and the radio access network nodes.

[0037] UEs 104, 105, 106, and 107 may include computing devices such as desktop computers, laptop computers, personal digital assistants (PDAs), tablet computers, smart TVs (e.g., TVs connected to the Internet), set-top boxes, game consoles, security systems (including security cameras), vehicle-mounted computers, network devices (e.g., routers, switches, and modems), or the like. According to embodiments of the present disclosure, UEs 104 to 107 may include portable wireless communication devices, smartphones, cellular phones, flip phones, devices with subscriber identity modules, personal computers, selective call receivers, or any other device capable of sending and receiving communication signals over a wireless network. In some embodiments, UEs 104 to 107 may include wearable devices such as smart watches, fitness bands, optical head-mounted displays, or the like. UEs 104 to 107 may also be referred to as subscriber units, mobile devices, mobile stations, users, terminals, mobile terminals, wireless terminals, fixed terminals, subscriber stations, user terminals, or devices, or may be described using other terms used in the art.

[0038] gNB 102 may receive packets 111, 112, and 113 (i.e., packets #1, #2, and #3) from core network 101 via shared bearer 121. Shared bearer 121 may be a GPRS Tunneling Protocol User Plane (GTP-U) tunnel (GPRS stands for General Packet Radio Service). gNB 102 may transmit the same MBS data (e.g., packets 111, 112, and 113) to UE 104 and UE 106 under the coverage of gNB 102. For example, the MBS data may be transmitted to UE 104 and UE 106 via point-to-multipoint (PTM) mode. The MBS data may be transmitted to UE 104 and UE 106 via a single-cell point-to-multipoint multicast radio bearer (SC-PTM MRB) 123.

[0039] gNB 103 may receive packets 111, 112, and 113 (i.e., packets #1, #2, and #3) from core network 101 via shared bearer 122. Shared bearer 122 may be a GTP-U tunnel. gNB 103 may transmit the same MBS data (e.g., packets 111, 112, and 113) to UE 105 and UE 107 under the coverage of gNB 103. For example, the MBS data may be transmitted to UE 105 and UE 107 via PTM mode. The MBS data may be transmitted to UE 105 and UE 107 via SC-PTM MRB 124. Handover of UE 104 to 107 occurs when UE 104 and / or UE 106 can move from the coverage of gNB 102 to the coverage of gNB 103 and UE 105 and / or UE 107 can move from the coverage of gNB 103 to the coverage of gNB 102.

[0040] MBS can be applied to public safety and mission-critical applications, V2X applications, transparent IPv4 / IPv6 multicast delivery, IPTV, wireless software delivery, group communications, and IoT applications. In these use cases, service continuity and reliability are highly demanding. For example, for software downloads, packets should not be missed during handovers.

[0041] Figure 2 is a flow chart illustrating a method for MBS with a handover procedure according to some embodiments of the present disclosure.

[0042] In LTE or NR, service continuity is supported between the source and target gNBs (or eNBs) for handovers. To support lossless data transmission, after a handover, the source gNB forwards all downlink Packet Data Convergence Protocol (PDCP) Service Data Units (SDUs) with their sequence numbers (SNs) that have not been confirmed by the UE as ready for handover to the target gNB. Additionally, the source gNB may forward recent data without PDCP SNs to the target gNB. The PDCP SN of the forwarded SDU is carried in the "PDCP PDU Number" field of the GTP-U extension header (PDU stands for Protocol Data Unit). If a PDCP SN is available in the forwarded GTP-U packet, the target gNB should use the PDCP SN. Because in-sequence delivery during handover is based on consecutive PDCP SNs, PDCP SN allocations should be aligned between the source and target gNBs.

[0043] Given the above, 5G MBS needs to support mobile service continuity between gNBs, which means lossless handover. Because in-sequence delivery during handover is based on continuous PDCP SNs (or PDCP counts), PDCP SNs (or PDCP counts) must be aligned between the source and target gNBs. However, 5G MBS needs to support PTM mode. In PTM mode, 5G MBS services are multicast within one or more cells. The source and target gNBs can assign independent SNs (or counts) to the same packet from the core network. Misalignment of SNs (or counts) between gNBs can lead to packet loss during handover from the source gNB to the target gNB.

[0044] exist Figure 2 In the exemplary method shown in FIG, the core network 101 may transmit MBS data (i.e., packet 111 or packet #1) to the source gNB 102 and the target gNB 103. Figure 2 In operation 641, the core network 101 transmits packet 111 (or packet #1) to the source gNB 102 via the shared bearer 121. Figure 2 In operation 643, core network 101 transmits the same packet 111 (or packet #1) to target gNB 103 via shared bearer 122. Shared bearers 121 and 122 may be GTP-U tunnels.

[0045] After receiving MBS data from the core network, the source gNB 102 assigns an SN (or PDCP SN) to the received MBS data. Figure 2In operation 642, source gNB 102 assigns an SN, e.g., 6, to received packet 111 (or packet #1). Source gNB 102 may transmit the packet with the assigned SN (e.g., a PDCP PDU with the assigned PDCP SN) to a UE (e.g., UE 104) under the coverage of source gNB 102. Figure 2 In operation 645, the source gNB 102 transmits packet 631 (including packet #1 and SN=6) to the UE 104 via the SC-PTM MRB 123.

[0046] After receiving the MBS data from the core network, the target gNB 103 assigns an SN (or PDCP SN) to the received MBS data. Figure 2 In operation 644, the target gNB 103 assigns an SN, e.g., 5, to the received packet 111 (or packet #1). The target gNB 103 may transmit the packet with the assigned SN (e.g., a PDCP PDU with the assigned PDCP SN) to a UE (e.g., UE 105) under the coverage of the target gNB 103. Figure 2 In operation 646, the target gNB 103 transmits packet 632 (including packet #1 and SN=5) to UE 105 via SC-PTM MRB124.

[0047] In different gNBs, the same packet (e.g., packet 111 or packet #1) may be assigned different SNs. Figure 2 In the figure, packet 111 (or packet #1) is assigned SN=6 by gNB 102, and packet 111 (or packet #1) is assigned SN=5 by gNB 103.

[0048] Handover of UE 104 occurs when UE 104 moves from the coverage of source gNB 102 to the coverage of target gNB 103. Figure 2 In operation 647, the handover procedure of UE 104 from source gNB 102 to target gNB 103 is triggered.

[0049] The MBS session of UE 105 under the target gNB 103 can still be activated, and the corresponding MBS data can be transmitted from the core network 101 to the target gNB 103. Figure 2 In operation 648, the core network 101 transmits packets 112 and 113 (or packets #2 and #3) to the target gNB 103. After receiving the MBS data from the core network, the target gNB 103 assigns an SN (or PDCP SN) to the received MBS data. Figure 2, operation 644 is performed again after receiving packets 112 and 113 (or packets #2 and #3), and the target gNB 103 assigns SNs to packets 112 and 113 (or packets #2 and #3).

[0050] After or during the handover procedure, the source gNB 102 informs the target gNB 103 of all PDCP SDUs with their SNs that have not been confirmed by the UE as available for handover. For example, the source gNB 102 may report to the target gNB 103 the SN of the next packet to be sent or received. Figure 2 In operation 649, source gNB 102 reports that the next packet to be sent (or to be received via shared bearer 122) is SN=7.

[0051] The target gNB 103 may transmit packets with the assigned SN (e.g., PDCP PDUs with the assigned PDCP SN) to the UE 105. Figure 2 In operation 650, target gNB 103 transmits packet 633 (including packet #2 and SN=6) to UE 105 via SC-PTM MRB 124. Figure 2 In operation 651, the target gNB 103 transmits packet 634 (including packet #2 and SN=6) to the UE 105 via the SC-PTM MRB 124.

[0052] The target gNB 103 may transmit the first packet to the newly entered UE based on the UE's report. Figure 2 In operation 652, based on the report from UE 104, target gNB 103 transmits packet 634′ (containing packet #3 and SN=7; which is the same as packet 634) because UE 104 reports that the next packet to be sent (or received) is SN=7. UE 104 does not receive packet 112 (or packet #2) from either the source gNB or the target gNB. Due to the SN misalignment between the source gNB and the target gNB, UE 104 loses packet 112 (or packet #2).

[0053] Figure 3 is a flow chart illustrating a method for MBS with smooth switching according to some embodiments of the present disclosure.

[0054] exist Figure 3In the exemplary method shown in FIG, an end marker indication (e.g., included in packet 191 or 191′) and a dedicated bearer for service continuity are introduced. The end marker indication may indicate the end of a data packet to be transmitted from a source gNB to a target gNB. In some embodiments, the end marker indication may be unique to a UE. During or after a handover procedure for UE 104, target gNB 103 may receive forwarded data and the end marker indication from source gNB 102. The target gNB may transmit the forwarded data to UE 104 via a dedicated bearer. The UE receives the forwarded packet via the dedicated bearer and the packet via the new SC-PTM MRB. With the end marker indication and dedicated bearer, lossless and seamless handover can be supported.

[0055] exist Figure 3 In the present embodiment, UE 104 may receive 5G MBS services from source gNB 102 in PTM mode via an MRB (e.g., an SC-PTM MRB). A shared bearer (e.g., a shared GTP-U tunnel) may be used between core network 101 (e.g., a user plane function (UPF) in the 5G core network) and source gNB 102. Shared bearer 121 may transport data packets for 5G MBS services for PTM mode and / or PTP mode and / or use of MRBs and / or unicast data radio bearers (DRBs). Target gNB 103 may also have an MRB for data transmission of the same MBS service in PTM mode. For example, the MRB of source gNB 102 may be SC-PTM MRB 123, and the MRB of target gNB 103 may be SC-PTM MRB 124.

[0056] exist Figure 3 In the exemplary method shown in FIG, the core network 101 may transmit MBS data (i.e., packet 111 or packet #1) to the source gNB 102 and the target gNB 103. Figure 3 In operation 141, the core network 101 transmits packet 111 (or packet #1) to the source gNB 102 via the shared bearer 121. Figure 3 In operation 143, core network 101 transmits the same packet 111 (or packet #1) to target gNB 103 via shared bearer 122. Shared bearers 121 and 122 may be GTP-U tunnels. Shared bearers may also be referred to as common bearers or common GTP-U tunnels.

[0057] After receiving MBS data from the core network, the source gNB 102 assigns an SN (or PDCP SN or PDCP count value) to the received MBS data. Figure 3In operation 142, source gNB 102 assigns an SN, e.g., 6, to received packet 111 (or packet #1). Source gNB 102 may transmit the packet with the assigned SN (e.g., a PDCP PDU with the assigned PDCP SN) to a UE (e.g., UE 104) under the coverage of source gNB 102. Figure 3 In operation 145, source gNB 102 transmits packet 131 (including packet #1 and SN=6) via SC-PTMMRB 123.

[0058] After receiving the MBS data from the core network, the target gNB 103 assigns an SN (or PDCP SN) to the received MBS data. Figure 3 In operation 144, the target gNB 103 assigns an SN, e.g., 5, to the received packet 111 (or packet #1). The target gNB 103 may transmit the packet with the assigned SN (e.g., a PDCP PDU with the assigned PDCP SN) to a UE (e.g., UE 105) under the coverage of the target gNB 103. Figure 3 In operation 146, the target gNB 103 transmits packet 132 (including packet #1 and SN=5) via SC-PTM MRB124.

[0059] In different gNBs, the same packet (e.g., packet 111 or packet #1) may be assigned different SNs. Figure 3 In the figure, packet 111 (or packet #1) is assigned SN=6 by gNB 102, and packet 111 (or packet #1) is assigned SN=5 by gNB 103.

[0060] A handover occurs when UE 104 moves from the coverage of source gNB 102 to the coverage of target gNB 103. Figure 3 In operation 147, the handover procedure of UE 104 from source gNB 102 to target gNB 103 is triggered.

[0061] During the handover procedure, source gNB 102 (e.g., source NG-RAN) may transmit a handover request to target gNB 103 (e.g., target NG-RAN). NG-Radio Access Node (RAN) is a new RAN defined by 3GPP in conjunction with 5G.

[0062] During the handover procedure, the UE index of the UE 104 being handed over may be assigned by either the source gNB 102 or the target gNB 103. The UE index may be a cell radio network temporary identifier (C-RNTI), a UE ID associated with the Xn interface, or another suitable ID. If the UE index is assigned by the source gNB 102, the source gNB 102 forwards the UE index to the target gNB 103 in the Handover Request message. If the UE index is assigned by the target gNB 103, the target gNB 103 forwards the UE index to the source gNB 102 in the Handover Request Confirm message. The UE index may be used to set and identify a UE-specific end marker indication. In some embodiments, the end marker indication may be unique to the UE. The source gNB 102 may also transmit a "Required Data Forwarding" indication to the target gNB 103. In some embodiments, the "Required Data Forwarding" indication may be unique to the 5G MBS session or unique to the 5G MBS bearer.

[0063] Source gNB 102 may also transmit information about ongoing 5G MBS sessions, radio bearers, and modes to the target gNB. Target gNB 103 may decide to use PTM mode. Based on the "data forwarding required" indication, target gNB 103 may configure dedicated DRBs to transmit forwarded data packets to a UE (e.g., UE 104). Dedicated DRBs may be used to transmit forwarded data packets received from source gNB 102.

[0064] After a handover procedure from source gNB 102 to target gNB 103, target gNB 103 may transmit a path switch indication for the 5G MBS session to core network 102 (e.g., an access and mobility management function (AMF) in the 5G core network). A UE index may be transmitted with or included in the path switch indication. The AMF forwards the path switch indication to the UPF. The path switch indication may indicate that a UE (e.g., UE 104) should be handed over to the target gNB and will receive data for this 5G MBS session in target gNB 103.

[0065] exist Figure 3 In operation 148, target gNB 103 transmits a path switch indication and a UE index (of UE 104) to core network 101. In some embodiments, operation 148 may include an acknowledgment message from core network 101 to target gNB 103.

[0066] After receiving the path switch indication and the UE index, the core network 101 (e.g., UPF) may immediately transmit one or more "end marker indications with UE index" packets on a shared bearer (e.g., a GTP-U tunnel) to the source gNB 102. For example, the core network (e.g., UPF) may transmit one or more "end marker indications with UE index" packets before a specific data packet or between two specific data packets. In some embodiments, the end marker indication and UE index may be indicated in the GTP-U header of the 5G MBS session. In some embodiments, the end marker indication and UE index may be provided by a GTP-U packet.

[0067] exist Figure 3 In operation 149, the core network 101 transmits packets 112, 113, and 114 (or packets #2, #3, and #4) and a packet 191 including an end marker indicator and a UE index via the shared bearer 121. The packet 191 including the end marker indicator and the UE index may be transmitted before the packet 114 (or packet #4) or between the packets 113 and 114 (or packets #3 and #4).

[0068] After receiving the "End Marker Indication with UE Index" packet, if forwarding functionality is activated for the bearer receiving the "End Marker Indication with UE Index" packet, source gNB 102 may forward or transmit the end marker indication and / or some packets to target gNB 103 via a shared data forwarding tunnel. In some embodiments, after receiving the "End Marker Indication with UE Index" packet, source gNB 102 may identify the UE (e.g., UE 104) by the UE index and forward or transmit the end marker indication and / or some packets to the target gNB via one or more UE-specific GTP-U tunnels. A dedicated UE-specific GTP-U tunnel may be established between source gNB 102 and target gNB 103 for data packet forwarding. For example, source gNB 102 may transmit packets 112 and 113 (or packets #2 and #3) and one or more end marker indications to target gNB 103. In some embodiments, source gNB 102 may transmit packets 112 and 113 (or packets #2 and #3) with assigned PDCP SNs or count values ​​and one or more end marker indications to target gNB 103.

[0069] exist Figure 3In operation 150, source gNB 102 transmits packets 112 and 113 (or packets #2 and #3) and packet 191′ (including an end marker indication) to target gNB 103. Packets 112 and 113 (or packets #2 and #3) may include an SN assigned by source gNB 103. In some embodiments, source gNB 102 may transmit data packets to target gNB 103, followed by data packets that were not successfully transmitted to UE 104. In some embodiments, source gNB 102 may transmit data packets received before the end marker indication and not yet acknowledged by UE 104 to target gNB 103. In some cases, a dedicated UE-specific GTP-U tunnel may be established between the source gNB and the target gNB for data forwarding. In some cases, a shared GTP-U tunnel may be established between the source gNB and the target gNB for data forwarding.

[0070] The MBS session of UE 105 under the target gNB 103 can still be activated, and the corresponding MBS data can be transmitted from the core network 101 to the target gNB 103. Figure 3 In operation 151, the core network 101 transmits packet 112 (or packet #2) to the target gNB 103. After receiving the MBS data from the core network, the target gNB 103 assigns an SN (or PDCP SN) for the received MBS data ( Figure 3 not shown).

[0071] The target gNB 103 may transmit packets with the assigned SN (e.g., PDCP PDUs with the assigned PDCP SN) to the UE 105. Figure 3 In operation 152, the target gNB 103 transmits packet 133 (including packet #2 and SN=6) via SC-PTM MRB 124.

[0072] Upon detecting the "end marker indication," target gNB 103 may discard the packet containing the end marker indication and transmit data packets prior to the end marker indication via a dedicated DRB or dedicated unicast bearer associated with SC-PTM MRB 123 or the PTP mode of SC-PTM MRB. Target gNB 103 may continue to use the PDCP SN or count value assigned by source gNB 102. In some embodiments, if no PDCP-SN is assigned for packets from source gNB 102, target gNB 103 may use the PDCP SN value contained in the DL Count Value IE (referring to the Downlink Count Value Information Element) for the first downlink packet. The DL Count Value IE may be sent by the source gNB.

[0073] exist Figure 3In operation 153 of the embodiment, after receiving the end marker indication, target gNB 103 transmits packets 112 and 113 (or packets #2 and #3) to UE 104 via a dedicated DRB or dedicated bearer 126 associated with SC-PTM MRB 123 or the PTP mode of SC-PTM MRB. Packets 112 and 113 (or packets #2 and #3) may include the SN assigned by the source gNB. In some embodiments, target gNB 103 may transmit data packets received from the source gNB before the end marker indication to UE 104.

[0074] After receiving the data packet from the target gNB 103, the dedicated bearer 126 may be released. For the target gNB 103, once the data packet received before the end marker indication (i.e., packet 191′) has been transmitted by the UE 104 or acknowledged by the UE 104, the target gNB 103 may release the dedicated bearer 126. For the UE 104, the UE may release the dedicated bearer 126 when a timer expires or when the UE receives a command from the core network 101. In some embodiments, the target gNB 103 may transmit the end marker indication to the UE 104 via the dedicated bearer 126. In this case, the target gNB 103 may release the dedicated bearer 126 when the end marker indication has been transmitted by the UE 104 or acknowledged by the UE 104; upon receiving the end marker indication, the UE 104 may release the dedicated bearer 126.

[0075] The MBS session of UE 105 under target gNB 103 can still be activated, and the corresponding MBS data can be transmitted from core network 101 to target gNB 103. Figure 3 In operation 154, the core network 101 transmits packets 113 and 114 (or packets #3 and #4) to the target gNB 103. After receiving the MBS data from the core network, the target gNB 103 may assign an SN (or PDCP SN) for the received MBS data ( Figure 3 not shown).

[0076] The target gNB 103 may transmit packets with the assigned SN (e.g., PDCP PDUs with the assigned PDCP SN) to the UE 105. Figure 3 In operation 155, target gNB 103 transmits packets 134 and 135 to UE 105 via SC-PTM MRB 124. Packet 134 includes packet #3 and SN=7; packet 135 includes packet #4 and SN=8.

[0077] Since UE 104 joins the MBS session under target gNB 103, target gNB 103 may transmit packets with the assigned SN (e.g., PDCP PDUs with the assigned PDCP SN) to UE 104. Figure 3 In operation 156, target gNB 103 transmits packets 134′ and 135′ via SC-PTM MRB 124. Packet 134′ includes packet #3 and SN=7; packet 135′ includes packet #4 and SN=8. Packets 134′ and 135′ may be the same as packets 134 and 135, respectively. Figure 3 As shown in FIG, UE 104 may receive data packets #2 and #3 (as described in operation 152) from target gNB 103 via dedicated bearer 126 (e.g., dedicated DRB) and data packets #3 and #4 (as described in operation 156) from target gNB 103 via SC-PTM MRB 124.

[0078] exist Figure 3 In FIG, when the handover procedure of UE 104 from source gNB 102 to target gNB 103 is triggered, UE 104 may also receive packets from target gNB 103 via SC-PTM MRB 124, such as Figure 2 . However, UE 104 further receives packets preceding the end marker indication via a dedicated bearer (e.g., a dedicated DRB), which are forwarded from source gNB 102 to target gNB 103. The packets preceding the end marker indication may include one or more packets that UE 104 did not receive from SC-PTM MRBs 123 and 124. Thus, when utilizing the end marker indication and dedicated bearers, no packets are lost during handover.

[0079] Figure 4 is a flow chart illustrating a method for MBS with count value alignment according to some embodiments of the present disclosure.

[0080] exist Figure 4 In the exemplary method shown in FIG, the PDCP count values ​​between different gNBs are aligned with the “first packet indication” transmitted from the core network.

[0081] Data packets for 5G MBS services in PTM mode may be transported via an MRB (e.g., SC-PTMMRB 123) in source gNB 102. A shared bearer 121 (e.g., a shared GTP-U tunnel) may be used between core network 101 (e.g., a UPF of core network 101) and source gNB 102. Shared bearer 121 may transport data packets for 5G MBS services for use with MRBs and / or unicast data radio bearers (DRBs).

[0082] exist Figure 4 In the exemplary method shown in FIG, the core network 101 may transmit MBS data (i.e., packet 111 or packet #1) to the source gNB 102 via a shared bearer 121 (e.g., a shared GTP-U tunnel). Figure 4 In operation 241, the core network 101 transmits packet 111 (or packet #1) to the source gNB 102 via the shared bearer 121.

[0083] After receiving the MBS data packets from the core network, the source gNB 102 assigns consecutive SNs (or PDCP SNs, PDCP count values) to the received MBS data packets. Figure 4 In operation 242, the source gNB 102 assigns an SN to the received packet 111 (or packet #1).

[0084] Source gNB 102 may transmit packets with assigned SNs (e.g., PDCP PDUs with assigned PDCP SNs) to UEs (e.g., UE 104) under the coverage of source gNB 102. Figure 4 In operation 243, source gNB 102 transmits packet 231 (including packet #1 and SN=6) via SC-PTMMRB 123.

[0085] Consider the case where UE 104 moves from the coverage of source gNB 102 to the coverage of target gNB. In the case where UE 104 moves from the coverage of source gNB 102 to the coverage of target gNB, a handover of UE 104 occurs. Figure 4 In operation 244 of the method, a handover procedure is triggered for UE 104 from source gNB 102 to target gNB 103. In some embodiments, in operation 244, the target gNB may start the same MBS as the MBS activated by UE 104 and source gNB 102.

[0086] The target gNB 103 may be triggered to establish a 5G MBS session between the target gNB 103 and the core network 101. For example, the target gNB 103 may transmit a path switch indication or a join multicast service indication to the core network. The core network 101 may be aware that gNB2 starts transmitting packets for the 5G MBS session. For example, the core network 101 may be aware that gNB2 starts transmitting packets for a 5G MBS session that is already activated between the UE 104 and the source gNB 102. The path switch indication may be carried by an NG interface message. The path switch indication may include a 5G MBS session ID or a temporary mobile group identity (TMGI). The join multicast service indication may be provided in the (Internet Protocol) IP layer. In Figure 4In operation 245, the target gNB 103 transmits a path switching indication or a join multicast session indication to the core network.

[0087] After receiving a path switch indication or a join multicast session indication, core network 101 may transmit a "first packet indication" to source gNB 102, indicating the first data packet to be transmitted by the target gNB to the UE in the handover. Core network 101 (e.g., UPF) may transmit a "first packet indication for target gNB 103" to source gNB 102. The first packet indication may be carried in a GTP-U header. The first packet indication may indicate which of the current packet, next packet, or previous packet is the first packet sent from core network 101 to target gNB 103. The first packet indication may include information about target gNB 103, such as the gNB 103 ID.

[0088] exist Figure 4 In operation 246 of FIG. 24, core network 101 transmits packet 291 including a "first packet indication." The first packet indication may be followed by subsequent data packets for an MBS session between UE 104 and source gNB 102. For example, packet 291 may be followed by packets 112 and 113 (or packets #2 and #3). After receiving packets 112 and 113 (or packets #2 and #3) from the core network, source gNB 102 may assign an SN (or PDCP SN) to packets 112 and 113 (or packets #2 and #3). Figure 4 not shown).

[0089] Source gNB 102 may transmit the corresponding PDCP count value to target gNB 103. Source gNB 102 may transmit the PDCP count value for the packet indicated in the "first packet indication" (e.g., the current packet, the next packet, or the previous packet). Source gNB 102 may transmit the PDCP count value to target gNB 103 based on information from target gNB 103 (which may be in the first packet indication). The PDCP count value may be in the First PDCP Count Value IE in the SN Status Transfer message or in a New Non-UE Associated message from source gNB 102 to target gNB 103.

[0090] exist Figure 4 In operation 247, source gNB 102 transmits an indication to target gNB 103. The indication transmitted by source gNB 102 may indicate a PDCP count value (or SN) for the next packet. For example, the indication from source gNB 102 to target gNB 103 indicates that the first packet received by target gNB 103 (i.e., packet #2 or packet 112) has an SN of 7.

[0091] exist Figure 4In operation 248, source gNB 102 may still transmit packet 236 (including packet #2 and SN=7) to UE 104 via SC-PTM MRB 123. Source gNB 102 may transmit an indication as described in operation 247 and transmit packet 236 (including packet #2 and SN=7) to UE 104 (as described in operation 248). In some embodiments, source gNB 102 may not transmit packet 236 to UE 104.

[0092] Since the MBS session under the target gNB 103 may be activated due to operation 244, the corresponding MBS data may be transmitted from the core network 101 to the target gNB 103. In some embodiments, the first data packet transmitted from the core network 101 to the target gNB 103 may be the data packet transmitted to the source gNB 102 after the "first packet indication". Figure 4 In operation 249, core network 101 transmits packets 112 and 113 (or packets #2 and #3) to target gNB 103. Packet 112 (or packet #2) is the first data packet transmitted from core network 101 to target gNB 103 and is identical to packet 112 (or packet #2) transmitted to source gNB 102 after the "first packet indication."

[0093] After receiving packets 112 and 113 (or packets #2 and #3) from the core network, target gNB 103 assigns an SN (or PDCP SN) to packets 112 and 113 (or packets #2 and #3). Target gNB 103 may assign the PDCP count value (or SN) indicated by source gNB 102 to the first packet received from core network 101. Target gNB 103 may continuously assign PDCP count values ​​(or SN) to subsequent packets. Target gNB 103 may assign the PDCP count value indicated in the first count value IE to the first packet received from core network 101 and assign consecutive PDCP count values ​​to subsequently received packets. Figure 4 In operation 250, the target gNB assigns SN=7 to the first received packet (i.e., packet #2 or packet 112). The PDCP count values ​​between source gNB 102 and target gNB 103 may be aligned. For subsequently received packets, target gNB 103 may assign consecutive PDCP count values ​​(or SNs). For example, the target gNB assigns SN=8 to the second received packet (i.e., packet #3 or packet 113).

[0094] Since UE 104 joins the MBS session under target gNB 103, target gNB 103 may transmit packets with the assigned SN (e.g., PDCP PDUs with the assigned PDCP SN) to UE 104. Figure 4In operation 251, target gNB 103 transmits packets 236′ and 237 via SC-PTM MRB 124. Packet 236′ includes packet #2 and SN=7; packet 237 includes packet #3 and SN=8. Packet 236′ may be identical to packet 236. UE 104 may receive all packets and not lose any packets during the handover.

[0095] In some embodiments, gNB 102 and gNB 103 may be the source gNB and target gNB, respectively, during handover. In some other embodiments, gNB 102 may be the anchor gNB for PDCP count allocation, and gNB 103 may be the serving gNB for the anchor gNB.

[0096] Figure 5 is a flow chart illustrating a method for MBS with count value alignment according to some embodiments of the present disclosure.

[0097] exist Figure 5 In the exemplary method presented in [1], an anchor PDCP concept is introduced to maintain alignment of PDCP SNs or count values ​​between gNBs. The PDCP SN or count value assignment functionality for a specific 5G MBS data transmission is provided only in a single gNB. The gNB with the PDCP SN or count value assignment functionality is defined as the anchor gNB. The anchor gNB can be selected in a specific area. Other gNBs used for the same 5G MBS data transmission in the specific area can connect to the anchor gNB. The gNB connected to the anchor gNB used for the same 5G MBS data transmission in the specific area is defined as the serving gNB.

[0098] like Figure 5 As shown in FIG, anchor gNB 102 may have a 5G MBS session connection with core network 101. Data for the 5G MBS session may be processed in the PDCP layer of anchor gNB 102. The anchor gNB (or primary gNB) may distribute associated PDCP PDUs to neighboring gNBs (or secondary gNBs, serving gNBs, or slave gNBs) via the Xn interface.

[0099] exist Figure 5In the exemplary method shown in

[15] , serving gNB 103 may obtain information about anchor gNB 102 from anchor gNB 102, from core network 101, or through operations and maintenance (OAM) configuration distributed throughout the network or system. Different anchor gNBs may be assigned for different 5G MBS services. For example, different anchor gNBs may be selected for different MBS sessions identified by TMGI. Upon determining the anchor gNB for a particular 5G MBS service, the anchor gNB may transmit the anchor gNB information to neighboring gNBs via an Xn Setup or Xn Configuration Update procedure over the Xn interface. Alternatively, the anchor gNB may transmit the anchor gNB information to the core network, and the core network may forward the anchor gNB information to the neighboring gNBs via an NG Setup or NG Configuration Update message over the NG interface.

[0100] In operation 341, the anchor gNB 102 transmits an anchor gNB indication to the serving gNB 103. The anchor gNB indication may include information of the anchor gNB 102. The anchor gNB indication may be transmitted from the anchor gNB 102 to the serving gNB 103 via an Xn interface.

[0101] Alternatively, anchor gNB 102 may transmit information about anchor gNB 102 to core network 101, and core network 101 may then notify serving gNB 103 of the anchor gNB information. In operation 342, core network 101 transmits an anchor gNB indication to serving gNB 103. The anchor gNB indication may include information about anchor gNB 102. The anchor gNB indication may be transmitted from core network 101 to serving gNB 103 via the NG interface. In view of the foregoing, either step 341 or step 342 may be performed alternatively.

[0102] The core network 101 may transmit the MBS data (i.e., packet 111 or packet #1) to the anchor gNB 102 via a shared bearer 121 (e.g., a shared GTP-U tunnel). Figure 5 In operation 343, core network 101 transmits packets 111 and 112 (or packets #1 and #2) to anchor gNB 102 via shared bearer 121.

[0103] After receiving MBS data packets from the core network, the anchor gNB 102 assigns consecutive SNs (or PDCP SNs, PDCP count values) to the received MBS data packets. Figure 5 In operation 344, anchor gNB 102 assigns consecutive SNs to received packets 111 and 112 (or packets #1 and #2).

[0104] Anchor gNB 102 may transmit packets with assigned SNs (e.g., PDCP PDUs with assigned PDCP SNs) to UEs (e.g., UE 104) under the coverage of anchor gNB 102. Figure 5 In operation 345, anchor gNB 102 transmits packet 2331 (including packet #1 and SN=6) via SC-PTM MRB 123.

[0105] Consider the case where UE 104 moves from the coverage of anchor gNB 102 to the coverage of serving gNB 103. In the case where UE 104 moves from the coverage of anchor gNB 102 to the coverage of serving gNB 103, a handover of UE 104 occurs. Figure 5 In operation 346 of the process, a handover procedure is triggered for UE 104 from anchor gNB 102 to serving gNB 103. In some embodiments, in operation 346, the serving gNB may start the same MBS service as the MBS activated by UE 104 and anchor gNB 102.

[0106] When the serving gNB 103 wishes to establish an MRB for 5G MBS service, the serving gNB 103 may transmit the required 5G MBS add message to the anchor gNB. Figure 5 In operation 347, the serving gNB 103 transmits the required 5G MBS add message to the anchor gNB 102. The message includes the 5G MBS session ID (e.g., TMGI).

[0107] In response to the required 5G MBS add message from the serving gNB 103, the anchor gNB 102 may transmit a 5G MBS add request message to the serving gNB 103. Figure 5 In operation 348, anchor gNB 102 transmits a 5G MBS Add Request message to serving gNB 103. The 5G MBS Add Request message from anchor gNB 102 may include PDCP-related configurations (PDCP-Config) for one or more associated 5G MRBs. The PDCP-related configurations may be carried in a radio resource control (RRC) container, such as the RadioBearerConfig IE. A list of MRBs may be included because a 5G MBS session may include multiple MRBs.

[0108] In response to the 5G MBS Add Request message from the anchor gNB 102, the serving gNB 103 may transmit a 5G MBS Add Confirm message to the anchor gNB 102. Figure 5 In operation 349, the serving gNB 103 transmits a 5G MBS add confirm message to the anchor gNB 102.

[0109] GTP-U tunnel (TNL) information (e.g., Internet Protocol (IP) address and tunnel endpoint identifier (TEID)) may be allocated by serving gNB 103 for one or more associated MRBs. Serving gNB 103 may also transmit the GTP-U TNL information to anchor gNB 102 via a 5G MBS Add Confirm message. A GTP-U tunnel may be established between anchor gNB 102 and serving gNB 103 using the GTP-U TNL information.

[0110] The anchor gNB 102 may transmit subsequent PDCP PDUs of the 5G MBS to the serving gNB 103 via the GTP-U tunnel, wherein the transmitted PDCP PDUs have been assigned an SN or a count value by the anchor gNB 102. Figure 5 In operation 350, anchor gNB 102 transmits packet 332 (including packet #2 and SN=7) to serving gNB 103. In some embodiments, anchor gNB 102 may transmit a PDCP SDU to serving gNB 103 via the GTP-U tunnel, wherein the PDCP SDU may not include an SN or a count value assigned by anchor gNB 102, but the SN or count value may be allocated by anchor gNB 102 and transmitted in a GTP-U header.

[0111] Serving gNB 103 may transmit an RRC MRB configuration message to UE 104 to establish an MRB between serving gNB 103 and UE 104. The RRC MRB configuration message may include the PDCP-configuration (PDCP-related configuration) from anchor gNB 102 and lower configurations generated by serving gNB 103 (e.g., cell group configuration including RLC, MAC, and PHY configurations). Figure 5 In operation 351, the serving gNB 103 transmits an SC-PTM MRB RRC configuration message to the UE 104 to establish an SC-PTM MRB between the serving gNB 103 and the UE 104.

[0112] After the MRB is established between the serving gNB 103 and the UE 104, the serving gNB 103 may transmit packets received from the anchor gNB 102 to the UE 104. Figure 5In operation 352, serving gNB 103 transmits packet 332 (including SN=7 and packet #2) to UE 104 via SC-PTM MRB 124. Packet 332 transmitted from serving gNB 103 to UE 104 is received from anchor gNB 102 in operation 350. UE 104 can receive all packets and no packets are lost during the handover. SC-PTMMRB 124 is established by the message and configuration transmitted in operation 351.

[0113] If the situation is that UE 104 moves further from the coverage of serving gNB 103 to the coverage of new gNB, then the new gNB performs steps 347 to 350 with anchor gNB 102 in order to assign the same PDCP SN as anchor gNB 102.

[0114] Figure 6 A flow chart illustrating a method for MBS with count value alignment according to some embodiments of the present disclosure is presented.

[0115] exist Figure 6 In the exemplary method shown in FIG, PDCP SNs between different gNBs are aligned based on information from the core network 101. For example, the gNBs may assign the same PDCP SN or count value to packets based on some sequence number of the packets (e.g., GTP-U SN, SYNC information, or other SN assigned by the core network).

[0116] exist Figure 6 In

[15] , the core network 101 may transmit MBS data (i.e., packets 111 and 112 or packets #1 and #2) to the anchor gNB 102 and the serving gNB 103. Figure 6 In operation 441, core network 101 transmits packets 111 and 112 (or packets #1 and #2) to anchor gNB 102 via shared bearer 121. Figure 6 In operation 442, core network 101 transmits the same packets 111 and 112 (or packets #1 and #2) to serving gNB 103 via shared bearer 122. Shared bearers 121 and 122 may be GTP-U tunnels.

[0117] After receiving MBS data from the core network, the anchor gNB 102 assigns an SN (or PDCP SN, PDCP count value) to the received MBS data. Figure 6 In operation 443, anchor gNB 102 assigns SNs to received packets 111 and 112 (or packets #1 and #2).

[0118] The anchor gNB may transmit the assigned PDCP SN (or PDCP count value) and the SN mapping rule indication to the neighboring gNB (or serving gNB). The neighboring gNB may use the same PDCP SN (or PDCP count value) for packets with the same SN assigned by the core network 101. Figure 6 In operation 444, the anchor gNB 102 transmits an SN mapping rule indication to the serving gNB 103. The SN mapping rule indication may include one or more PDCP SNs assigned by the anchor gNB (e.g., SN=6 and / or SN=7) and a mapping rule between the PDCP SNs and the SNs assigned by the core network 101. For example, the mapping rule may include "for packet #1, SN=6" and / or "for packet #2, SN=7," where "#1" and "#2" are assigned by the core network 101.

[0119] In LTE, synchronized radio interface transmissions from cells controlled by different eNBs require SYNC protocol support between the Broadcast Multicast Service Center (BM-SC) and the eNB. As part of the SYNC protocol procedure, the BM-SC includes a timestamp within the SYNC PDU packet, which informs the eNB when the MBMS data is sent over the air interface. The SYNC PDU header information includes a timestamp, a packet number, and an elapsed octet counter. If the SYNC protocol is used in 5G MBS, the anchor gNB may allocate a PDCP count value (or PDCP SN) associated with one or more SYNC header information and send a mapping between the PDCP count value (or PDCP SN) and the SYNC header information to the neighboring gNB (or serving gNB). The neighboring gNB (or serving gNB) may use the same PDCP count value (or PDCP SN) for packets with the same SYNC header information.

[0120] The GTP-U header may also include a two-byte sequence number. The anchor gNB may assign a PDCP count value (or PDCP SN) based on the SN in the GTP-U header (e.g., the GTP-U SN) and communicate the mapping rules between the PDCP count value (or PDCP SN) and the GTP-U SN to the neighboring gNB (or serving gNB). The neighboring gNB (or serving gNB) may use the same PDCP count value (or PDCP SN) for packets with the same GTP-U SN.

[0121] For example, the gNB may assign the same PDCP SN or counter value to packets based on their sequence numbers. A new SN for the NG interface may be added to the packets from the CN. The CN adds the SN for each packet. The NG interface SN may be included in a "RAN container" in the GTP-U extension header. For example, the gNB assigns the same PDCP SN or counter value as the NG interface SN.

[0122] After assigning the PDCP SN, anchor gNB 102 may transmit packets with the assigned SN (e.g., PDCP PDUs with the assigned PDCP SN) to UEs (e.g., UE 104) under the coverage of anchor gNB 102. Figure 6 In operation 445 , anchor gNB 102 transmits packet 431 (including packet #1 and SN=6) and packet 432 (including packet #2 and SN=6) to UE 104 via SC-PTM MRB 123 .

[0123] After receiving the MBS data and SN mapping rule indication from the core network, the serving gNB 103 assigns a PDCP SN (or PDCP count value) to the received MBS data. Figure 6 In operation 446 of the target gNB 103, the serving gNB 103 assigns a SN to the received packets 111 and 112 (or packets #1 and #2). The serving gNB 103 may transmit the packet with the assigned SN (e.g., a PDCP PDU with the assigned PDCP SN) to a UE (e.g., UE 105) under the coverage of the target gNB 103. Figure 6 In operation 447, serving gNB 103 transmits packet 431′ (including packet #1 and SN=6) and packet 432′ (including packet #2 and SN=7) to UE 105 via SC-PTM MRB 124. Packets 431′ and 432′ may be identical to packets 431 and 432, respectively.

[0124] Consider the case where UE 104 moves from the coverage of source gNB 102 to the coverage of target gNB. In the case where UE 104 moves from the coverage of source gNB 102 to the coverage of target gNB, a handover of UE 104 occurs. Figure 6 In operation 448, a handover procedure is triggered for UE 104 from anchor gNB 102 to serving gNB 103. The MBS session of UE 105 under serving gNB 103 can still be activated, and the corresponding MBS data can be transmitted from core network 101 to serving gNB 103. Figure 6In operation 449, the core network 101 transmits packets 113 and 114 (or packets #3 and #4) to the target gNB 103. After receiving the MBS data from the core network, the target gNB 103 assigns a PDCP SN (or a PDCP count value) to the received MBS data. Figure 6 In the example, the operation of assigning PDCP SN (or PDCP count value) to packets 113 and 114 (or packets #3 and #4) is as follows: Figure 6 After receiving packets 113 and 114 (or packets #3 and #4), serving gNB 103 may assign a PDCP SN (or PDCP count value) to packets 113 and 114 (or packets #3 and #4) based on the mapping rule indicated in the SN mapping rule indication transmitted in operation 444.

[0125] After the handover procedure, the UE entering the new gNB may report the status of the received packets to the new gNB. For example, the UE may report the PDCP SN of the next packet to be sent or received to the new gNB. Figure 6 In operation 450, UE 104 reports the status of the received packet to serving gNB 103. For example, UE 104 reports that the next packet to be sent (or to be received) is SN=8.

[0126] The target gNB 103 may transmit packets with the assigned SN (e.g., PDCP PDUs with the assigned PDCP SN) to the UE 105. Figure 6 In operation 451, serving gNB 103 transmits packet 433 (including packet #3 and SN=8) and packet 434 (including packet #4 and SN=9) to UE 105 via SC-PTM MRB 124. Figure 6 In operation 452, serving gNB 103 transmits packet 433 (including packet #3 and SN=8) and packet 434 (including packet #4 and SN=9) to UE 104 via SC-PTM MRB 124. Since the PDCP SNs (or PDCP count values) between anchor gNB 102 and serving gNB 103 are aligned, no packets are lost during the handover of UE 104.

[0127] Figure 7 1 is a flow chart illustrating a method for MBS according to some embodiments of the present disclosure. The method may be a method for handing over a user equipment (UE) from a first NB to a second NB and performed by the first NB (e.g., source gNB 102).

[0128] exist Figure 7In the exemplary method shown in FIG, in step 702, a first NB may transmit at least one first data packet. In step 704, the first NB may receive an alignment indication from a core network. According to some embodiments, the alignment indication is used to align PDCP SNs or PDCP count values ​​assigned by different NodeBs for the same data packet.

[0129] In some embodiments, the alignment indication may be an end marker indication indicating the end of the data packet to be transmitted to the second NodeB. The alignment indication may include an end marker indication in a General Packet Radio Service Tunneling Protocol-User Plane Packet (GTP-U) header. The source gNB may receive the UE index of the UE along with the alignment indication from the core network via a shared GTP-U tunnel. The shared GTP-U tunnel is used for data transmission for both multicast and unicast bearers of the 5G Multicast and Broadcast Service (MBS).

[0130] In the above embodiment with end marker indication, the method may further include: transmitting the end marker to the second NodeB via a UE-specific GTP-U tunnel, wherein the UE-specific GTP-U tunnel is based on the UE index; or transmitting the UE index with the end marker to the second NodeB via a shared GTP-U tunnel.

[0131] In the above embodiment with the end marker indication, the method may further include: transmitting at least one second data packet to the second NodeB, followed by the first data packet, wherein the at least one second data packet is determined based on the alignment indication. In some cases, a dedicated UE-specific GTP-U tunnel may be established between the source gNB and the target gNB for data forwarding. In some other cases, a shared GTP-U tunnel may be established between the source gNB and the target gNB for data forwarding.

[0132] In the above embodiment with the end marker indication, the method may further include: assigning a UE index to the UE; and sending the UE index to the second NodeB in the handover request message. The UE index of the UE may be received from the second NodeB in the handover request acknowledgement message. The at least one second data packet includes a Packet Data Convergence Protocol (PDCP) service data unit (SDU).

[0133] In some embodiments, the alignment indication may be an indication of at least one second data packet to be first transmitted by the second NodeB to the UE under handover. Figure 7 The method further includes transmitting a sequence number of the second data packet to the second NodeB. The sequence number includes a PDCP SN or a PDCP count value.

[0134] Figure 81 is a flow chart illustrating a method for MBS according to some embodiments of the present disclosure. The method may be performed by a second NB (e.g., gNB 103) for handover of a user equipment (UE) from a first NB to a second NB.

[0135] exist Figure 8 In the exemplary method shown in FIG, in step 802, the second NB may receive a handover message. In step 804, the second NB may transmit a plurality of data packets to the UE based on the alignment indication.

[0136] According to some embodiments, the alignment indication comprises an end marker indicated by a General Packet Radio Service Tunneling Protocol-User Plane (GTP-U) packet. In this case, Figure 8 The method may further include receiving an alignment indication via a UE-specific GTP-U tunnel, wherein the UE-specific GTP-U tunnel is based on a UE index. Alternatively, Figure 8 The method may further include receiving an alignment indication with a UE index via a shared GTP-U tunnel. The shared GTP-U tunnel may be used for data transmission of both a multicast bearer and a unicast bearer of a 5G Multicast and Broadcast Service (MBS). The plurality of data packets include a Packet Data Convergence Protocol (PDCP) service data unit (SDU).

[0137] According to some embodiments, the alignment indication indicates the end of the data packet to be received from the first NodeB. In this case, Figure 8 The method may further include: transmitting a path switch indication message and a UE index of the UE to the core network in response to the handover message. The UE index may be allocated by the second NodeB in response to the handover message. Alternatively, the UE index may be received from the first NodeB. In this case, Figure 8 The method may further comprise receiving at least one first data packet and an alignment indication from the first NodeB, wherein the at least one first data packet is determined based on the alignment indication. In this case, Figure 8 The method may further include: transmitting at least one first data packet to the UE via a unicast bearer; and transmitting at least one second data packet to the UE via a multicast radio bearer (MRB).

[0138] According to some embodiments, the alignment indication indicates a first data packet among the plurality of data packets to be transmitted first by the second NodeB to the UE. In this case, Figure 8 The method may further include: receiving a first sequence number of a first data packet assigned by the first NodeB from the first NodeB; and assigning a second sequence number of the first data packet that is the same as the first sequence number before transmitting the first data packet to the UE. The first sequence number and the second sequence number include a PDCP SN or a PDCP count value. In this case, Figure 8The method may further include: transmitting a path switch indication message to a core network in response to the switching message.

[0139] Figure 9 is a flow chart illustrating a method for MBS according to some embodiments of the present disclosure. The method may be performed by a network entity (eg, core network 101) for handover from a first NB to a second NB.

[0140] exist Figure 9 In the exemplary method illustrated in FIG, in step 902, a network entity may transmit a plurality of data packets via a GTP-U tunnel shared with a first NB. In step 904, the network entity may transmit a plurality of data packets via a GTP-U tunnel shared with a second NB. In step 906, the network entity may receive a path switch indication message from the second NB indicating a handover from the first NB to the second NB. In step 908, the network entity may transmit an alignment indication to the first NB.

[0141] According to some embodiments, an alignment indication indicates the end of a data packet to be transmitted from a first NodeB to a second NodeB. The alignment indication may include an end marker indicated by a General Packet Radio Service Tunneling Protocol-User Plane (GTP-U) packet. A UE index of the UE to be handed over is transmitted along with the alignment indication. The UE index may be transmitted along with the alignment indication via a shared GTP-U tunnel. The shared GTP-U tunnel is used for data transmission for both multicast bearers and unicast bearers of 5G Multicast and Broadcast Service (MBS).

[0142] According to some embodiments, the alignment indication indicates a first data packet to be first transmitted by the second NodeB to the UE. The alignment indication includes a sequence number of the first data packet. The sequence number includes a PDCP SN or a PDCP count value.

[0143] Figure 10 1 is a flow chart illustrating a method for MBS according to some embodiments of the present disclosure. The method may be a method for handing over a user equipment (UE) from a first NB to a second NB and performed by a UE (eg, UE 104), wherein at least one first data packet is forwarded from a first NodeB.

[0144] exist Figure 10 In the exemplary method shown in , in step 1002, the UE may receive at least one first data packet from the second NB via a unicast bearer. In step 1004, the UE may receive at least one second data packet from the second NB.

[0145] Figure 11 1 is a flow chart illustrating a method for MBS according to some embodiments of the present disclosure. The method may be performed by an anchor NB (e.g., gNB 102).

[0146] exist Figure 11 In the exemplary method shown in FIG, in step 1102, the anchor NB may receive a data packet from the core network. In step 1104, the anchor NB may assign a sequence number to the data packet.

[0147] The sequence number may include a PDCP SN or a PDCP count value. Figure 11 The method may further include transmitting an anchor indication message to the first NodeB. Figure 11 The method may further include: receiving a message requesting a multicast and broadcast service (MBS) from the first NodeB; and / or transmitting a request message including a Packet Data Convergence Protocol (PDCP) configuration to the first NodeB. The sequence number of the data packet may be transmitted to the first NodeB via a PDCP protocol data unit (PDU) or a PDCP service data unit (SDU) along with an SN indication. The sequence number of the data packet may be determined based on a GTP-U number or synchronization information in a synchronization protocol. Transmitting the sequence number of the data packet to the first NodeB may include transmitting a method for generating the sequence number to the first NodeB.

[0148] Figure 12 1 is a flowchart illustrating a method for MBS according to some embodiments of the present disclosure. The method may be performed by a NB (e.g., gNB 103).

[0149] exist Figure 12 In the exemplary method shown in FIG. 1 , in step 1202, the NB may receive an anchor indication message indicating an anchor NB. In step 1204, the anchor NB may receive a sequence number of a data packet of a multicast or broadcast service from the anchor NB.

[0150] The sequence number may include a PDCP SN or a PDCP count value. The anchor indication message is received from the core network or the anchor NodeB. Figure 12 The method may further include: transmitting a message requesting a multicast and broadcast service (MBS) to an anchor NodeB; and / or receiving a request message including a Packet Data Convergence Protocol (PDCP) configuration from the anchor NodeB. The sequence number of the data packet is transmitted to the first NodeB via a PDCP protocol data unit (PDU) or a PDCP service data unit (SDU) along with an SN indication. The sequence number of the data packet is determined based on a GTP-U number or synchronization information. Receiving the sequence number of the data packet for the multicast or broadcast service from the anchor NodeB may include receiving a sequence number generation method.

[0151] Figure 13A simplified block diagram of a device 1300 according to some embodiments of the present disclosure is shown. The device 1300 may be the gNB 102 or gNB 103 of the present disclosure.

[0152] refer to Figure 13 , the device 1300 may include at least one non-transitory computer-readable medium 1302, at least one receiving circuit system 1304, at least one transmitting circuit system 1306, and at least one processor 1308. In some embodiments of the present disclosure, the at least one receiving circuit system 1304 and the at least one transmitting circuit system 1306 can be integrated into at least one transceiver. The at least one non-transitory computer-readable medium 1302 may have computer-executable instructions stored therein. The at least one processor 1308 may be coupled to the at least one non-transitory computer-readable medium 1302, the at least one receiving circuit system 1304, and the at least one transmitting circuit system 1306. The computer-executable instructions may be programmed to implement a method using the at least one receiving circuit system 1304, the at least one transmitting circuit system 1306, and the at least one processor 1308. The method may be a method according to an embodiment of the present disclosure, for example Figures 2 to 8 , 11 and 12.

[0153] Figure 14 A simplified block diagram of a device 1400 according to some embodiments of the present disclosure is shown. The device 1400 may be the core network 101 of the present disclosure.

[0154] refer to Figure 14 , the device 1400 may include at least one non-transitory computer-readable medium 1402, at least one receiving circuit system 1404, at least one transmitting circuit system 1406, and at least one processor 1408. In some embodiments of the present disclosure, the at least one receiving circuit system 1404 and the at least one transmitting circuit system 1406 can be integrated into at least one transceiver. The at least one non-transitory computer-readable medium 1402 may have computer-executable instructions stored therein. The at least one processor 1408 may be coupled to the at least one non-transitory computer-readable medium 1402, the at least one receiving circuit system 1404, and the at least one transmitting circuit system 1406. The computer-executable instructions may be programmed to implement a method using the at least one receiving circuit system 1404, the at least one transmitting circuit system 1406, and the at least one processor 1408. The method may be a method according to an embodiment of the present disclosure, for example Figures 2 to 6 and one of the methods shown in 9.

[0155] Figure 15 1. A simplified block diagram of a device 1500 according to some embodiments of the present disclosure is shown. The device 1500 may be the UE 104 or the UE 105 of the present disclosure.

[0156] refer to Figure 15 , the device 1500 may include at least one non-transitory computer-readable medium 1502, at least one receiving circuit system 1504, at least one transmitting circuit system 1506, and at least one processor 1508. In some embodiments of the present disclosure, the at least one receiving circuit system 1504 and the at least one transmitting circuit system 1506 can be integrated into at least one transceiver. The at least one non-transitory computer-readable medium 1502 may have computer-executable instructions stored therein. The at least one processor 1508 may be coupled to the at least one non-transitory computer-readable medium 1502, the at least one receiving circuit system 1504, and the at least one transmitting circuit system 1506. The computer-executable instructions may be programmed to implement a method using the at least one receiving circuit system 1504, the at least one transmitting circuit system 1506, and the at least one processor 1508. The method may be a method according to an embodiment of the present disclosure, for example Figures 2 to 6 and one of the methods shown in 10.

[0157] The methods according to the embodiments of the present disclosure may also be implemented on a programmed processor. However, the controller, flow chart and module may also be implemented on a general or special-purpose computer, a programmed microprocessor or microcontroller and peripheral integrated circuit elements, an integrated circuit, a hardware electronic or logic circuit (such as a discrete element circuit), a programmable logic device or the like. In general, any device on which resides a finite state machine capable of implementing the flow chart shown in the figure can be used to implement the processor functions of the present application. For example, an embodiment of the present disclosure provides an apparatus for speech emotion recognition, which includes a processor and a memory. Computer programmable instructions for implementing the method for speech emotion recognition are stored in the memory, and the processor is configured to execute computer programmable instructions for implementing the method for speech emotion recognition. The method may be the method described above or other methods according to the embodiments of the present disclosure.

[0158] An alternative embodiment preferably implements the method according to an embodiment of the present disclosure in a non-transitory computer-readable storage medium storing computer programmable instructions. The instructions are preferably executed by a computer-executable component that is preferably integrated with a network security system. The non-transitory computer-readable storage medium may be stored on any suitable computer-readable medium, such as RAM, ROM, flash memory, EEPROM, optical storage device (CD or DVD), hard drive, floppy disk drive or any suitable device. The computer-executable component is preferably a processor, but the instructions may alternatively or additionally be executed by any suitable dedicated hardware device. For example, an embodiment of the present disclosure provides a non-transitory computer-readable storage medium having computer programmable instructions stored therein. The computer programmable instructions are configured to implement the method of speech emotion recognition described above or other methods according to embodiments of the present disclosure.

[0159] Although the present application has been described with reference to specific embodiments of the present application, it is apparent that many alternatives, modifications, and variations may be apparent to those skilled in the art. For example, the various components of the embodiments may be interchangeable, added, or substituted in other embodiments. Moreover, all elements of each figure are not necessary for the operation of the disclosed embodiments. For example, a person skilled in the art of the disclosed embodiments will be able to make and use the teachings of the present application by adopting only the elements of the independent claims. Therefore, the embodiments of the present application set forth herein are intended to be illustrative and not restrictive. Various changes may be made without departing from the spirit and scope of the present application.

Claims

1. A method performed by an anchor NodeB, the method comprising: receiving data packets from a core network; and Assigning a sequence number to the data packet, wherein the sequence number comprises a PDCP SN or a PDCP count value, and wherein the sequence number of the data packet is determined based on a GTP-U number or synchronization information in a synchronization protocol or a new SN assigned by the core network.

2. The method according to claim 1, further comprising: The sequence number of the data packet is transmitted to a first NodeB.

3. The method according to claim 1, further comprising: Transmitting an anchor indication message to the first NodeB; receiving a message requesting a multicast and broadcast service (MBS) from the first NodeB; and A request message including a Packet Data Convergence Protocol (PDCP) configuration is transmitted to the first NodeB.

4. A device for switching, comprising: at least one non-transitory computer-readable medium having computer-executable instructions stored therein; at least one receiver; at least one transmitter; and at least one processor coupled to the at least one non-transitory computer-readable medium, the at least one receiver, and the at least one transmitter; wherein the computer-executable instructions are executed by the at least one processor, causing the apparatus to: transmitting at least one first data packet to a user equipment UE; and receiving an alignment indication from a core network to support handover of the user equipment from the device to a second network device, wherein the alignment indication indicates a second data packet to be first transmitted by the second network node to the UE, and the processor causing the device to transmit a sequence number of the second data packet to the second network device, wherein the sequence number of the second data packet is determined based on a GTP-U number or synchronization information in a synchronization protocol or a new SN assigned by the core network.

5. The device of claim 4, wherein the alignment indication indicates an end of a data packet to be transmitted to the second network device.

6. The apparatus of claim 4, wherein the alignment indication comprises an end marker indicated by a General Packet Radio Service Tunneling Protocol-User Plane (GTP-U) packet.

7. The apparatus of claim 5, wherein a UE index of the UE is received from the core network along with the alignment indication, and wherein the UE index is received from the second network apparatus in a handover request confirm message.

8. The apparatus of claim 5 , wherein the UE index of the UE is received from the core network together with the alignment indication via a shared GTP-U tunnel, wherein the shared GTP-U tunnel is used for data transmission of both a multicast bearer and a unicast bearer of a 5G Multicast and Broadcast Service (MBS).

9. The apparatus of claim 8, wherein the processor causes the apparatus to: An end marker is transmitted to the second network node via a UE-specific GTP-U tunnel, wherein the UE-specific GTP-U tunnel is based on the UE index.

10. The apparatus of claim 5, wherein a UE index of the UE is received from the core network together with the alignment indication, and the processor causes the apparatus to: assigning the UE index to the UE, and The UE index is sent to the second network node in a handover request message.

11. A device for switching, comprising: at least one non-transitory computer-readable medium having computer-executable instructions stored therein; at least one receiver; at least one transmitter; and at least one processor coupled to the at least one non-transitory computer-readable medium, the at least one receiver, and the at least one transmitter; wherein the computer-executable instructions are executed by the at least one processor, causing the apparatus to: receiving a handover message from a second device, the second device attempting to handover a user equipment UE to the device, the device and the second device being nodes in a communication network; and transmitting a plurality of data packets to the UE based on an alignment indication, wherein the alignment indication indicates a first data packet among the plurality of data packets to be transmitted first by a second network node to the UE; and wherein the processor causes the apparatus to: A first sequence number of the first data packet assigned by a first network node is received from a first network node, wherein the first sequence number of the first data packet is determined based on a GTP-U number or synchronization information in a synchronization protocol or a new SN assigned by a core network.

12. The apparatus of claim 11 , wherein the alignment indication comprises an end marker indicated by a General Packet Radio Service Tunneling Protocol-User Plane (GTP-U) packet, wherein the processor causes the apparatus to receive the alignment indication via a UE-specific GTP-U tunnel, wherein the UE-specific GTP-U tunnel is based on a UE index.

13. The apparatus of claim 11 , wherein the processor causes the apparatus to: receiving the alignment indication with a UE index via a shared GTP-U tunnel; The shared GTP-U tunnel is used for data transmission of both multicast bearer and unicast bearer of 5G Multicast and Broadcast Service (MBS).

14. The apparatus of claim 11 , wherein the alignment indication indicates an end of a data packet to be received from the first network node, and the processor causes the apparatus to transmit a path switch indication message and a UE index of the UE to the core network in response to the handover message, wherein the UE index is one of: (i) assigned by the second network node in response to the handover message, or (ii) received from the first network node.

15. The apparatus of claim 14, wherein the processor causes the apparatus to: receiving at least one first data packet and the alignment indication from the first network node; wherein the at least one first data packet is determined based on the alignment indication; transmitting the at least one first data packet to the UE via a unicast bearer; and At least one second data packet is transmitted to the UE via a multicast radio bearer (MRB).

16. The apparatus of claim 11, wherein the processor causes the apparatus to: The first data packet is assigned a second sequence number that is the same as the first sequence number before transmitting the first data packet to the UE.

17. The apparatus of claim 11, further comprising: In response to the switching message, a path switching indication message is transmitted to the core network.

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