CN115668994A

CN115668994A - Transmission method and device of MBS (multicast broadcast multicast service) and communication equipment

Info

Publication number: CN115668994A
Application number: CN202080101102.6A
Authority: CN
Inventors: 王淑坤
Original assignee: Guangdong Oppo Mobile Telecommunications Corp Ltd
Current assignee: Guangdong Oppo Mobile Telecommunications Corp Ltd
Priority date: 2020-07-30
Filing date: 2020-07-30
Publication date: 2023-01-31
Also published as: CN116546443A; WO2022021235A1

Abstract

The embodiment of the application provides a transmission method, a device and communication equipment of MBS service, wherein the method comprises the following steps: the target base station receives the MBS service data forwarded by the original base station, and the target base station sends the MBS service data forwarded by the original base station to the terminal equipment in a unicast mode; and the target base station sends first indication information to the terminal equipment, wherein the first indication information is used for indicating the terminal equipment to reset a receiving window, and the reset receiving window is used for receiving the MBS service data sent by the target base station by the terminal equipment in a multicast mode.

Description

Transmission method and device of MBS (multicast broadcast multicast service) and communication equipment

Technical Field

The embodiment of the present application relates to the field of mobile communication technologies, and in particular, to a method and an apparatus for transmitting a Multimedia multicast Service (MBS) Service, and a communication device.

Background

After entering a Radio Resource Control (RRC) connection state, a terminal device can receive a Multimedia multicast Service (MBS) Service.

Different cells may have time differences for MBS service transmission, that is, MBS services transmitted by different cells are not synchronous, for example, MBS service transmitted by cell 1 is earlier or later than MBS service transmitted by cell 2, that is, how to ensure MBS service continuity in the handover process is a definite problem.

Disclosure of Invention

The embodiment of the application provides a transmission method and device of MBS service and communication equipment.

The transmission method for the MBS service provided in the embodiment of the present application includes:

the target base station receives the MBS service data forwarded by the original base station, and the target base station sends the MBS service data forwarded by the original base station to the terminal equipment in a unicast mode;

and the target base station sends first indication information to the terminal equipment, wherein the first indication information is used for indicating the terminal equipment to reset a receiving window, and the reset receiving window is used for receiving the MBS service data sent by the target base station by the terminal equipment in a multicast mode.

an original base station sends first auxiliary information to a target base station, wherein the first auxiliary information is used for the target base station to determine whether the original base station needs to forward MBS service data to the target base station;

the source base station receives third indication information sent by the target base station, wherein the third indication information is used for indicating the source base station to forward MBS service data to the target base station;

the source base station transmits MBS service data to the target base station and sends a switching command to the terminal equipment, wherein the switching command is used for triggering the terminal equipment to be switched from the original base station to the target base station and receiving the MBS service data sent by the target base station in a unicast mode and the MBS service data sent by the target base station in a multicast mode.

The transmission method of the MBS service provided by the embodiment of the application comprises the following steps:

the terminal equipment receives a switching command sent by an original base station and switches from the source base station to a target base station;

the terminal equipment sends sixth indication information to the target base station, wherein the sixth indication information is used for indicating a second PDCP SN list, and the second PDCP SN list refers to a missing PDCP SN list between the original base station and the target base station;

and the terminal equipment receives MBS service data sent by the target base station in a unicast mode and MBS service data sent in a multicast mode.

The transmission device for MBS service provided in the embodiment of the present application is applied to a target base station, and the device includes:

a receiving unit, configured to receive MBS service data forwarded by an original base station;

a sending unit, configured to send, according to a unicast manner, MBS service data forwarded by the original base station to a terminal device; and sending first indication information to the terminal equipment, wherein the first indication information is used for indicating the terminal equipment to reset a receiving window, and the reset receiving window is used for receiving MBS service data sent by the target base station by the terminal equipment according to a multicast mode.

The transmission device of the MBS service provided in the embodiment of the present application is applied to an original base station, and the device includes:

a sending unit, configured to send first auxiliary information to a target base station, where the first auxiliary information is used by the target base station to determine whether the original base station needs to forward MBS service data to the target base station;

a receiving unit, configured to receive third indication information sent by the target base station, where the third indication information is used to indicate the source base station to forward MBS service data to the target base station;

the sending unit is further configured to forward MBS service data to the target base station, and send a handover command to a terminal device, where the handover command is used to trigger the terminal device to handover from the original base station to the target base station, and receive the MBS service data sent by the target base station in a unicast manner and the MBS service data sent by the target base station in a multicast manner.

The transmission device of the MBS service provided in the embodiment of the present application is applied to a terminal device, and the device includes:

a receiving unit, configured to receive a handover command sent by an original base station, and handover the original base station to a target base station from the source base station;

a sending unit, configured to send sixth indication information to the target base station, where the sixth indication information is used to indicate a second PDCP SN list, and the second PDCP SN list refers to a missing PDCP SN list between the original base station and the target base station;

the receiving unit is further configured to receive MBS service data sent by the target base station in a unicast manner and MBS service data sent in a multicast manner.

The communication device provided by the embodiment of the application comprises a processor and a memory. The memory is used for storing computer programs, and the processor is used for calling and running the computer programs stored in the memory to execute the transmission method of the MBS service.

The chip provided by the embodiment of the application is used for realizing the transmission method of the MBS service.

Specifically, the chip includes: and the processor is used for calling and running the computer program from the memory so that the equipment provided with the chip executes the transmission method of the MBS service.

The computer-readable storage medium provided in the embodiments of the present application is used for storing a computer program, where the computer program enables a computer to execute the MBS service transmission method described above.

The computer program product provided by the embodiment of the present application includes computer program instructions, where the computer program instructions enable a computer to execute the MBS service transmission method.

The computer program provided in the embodiment of the present application, when running on a computer, enables the computer to execute the transmission method of the MBS service.

The technical scheme of the embodiment of the application provides a transmission method of the MBS service, which ensures the continuity of the MBS service data in the switching process, avoids the loss of the MBS service data and improves the transmission reliability of the MBS service data in the mobility process.

Drawings

The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the application and together with the description serve to explain the application and not to limit the application. In the drawings:

fig. 1 is a schematic diagram of a communication system architecture provided by an embodiment of the present application;

fig. 2 is a schematic diagram illustrating MBS service transmission in a multicast mode and a unicast mode according to an embodiment of the present application;

fig. 3 is a schematic diagram of cell handover provided in an embodiment of the present application;

fig. 4 is a first flowchart illustrating a transmission method of an MBS service according to an embodiment of the present application;

FIG. 5-1 is a diagram of a receive window before reset, as provided by an embodiment of the present application;

5-2 is a schematic diagram of a reset receiving window provided by an embodiment of the present application;

fig. 6 is a flowchart illustrating a second method for transmitting MBS services according to an embodiment of the present application;

fig. 7 is a third flowchart illustrating a transmission method of an MBS service according to an embodiment of the present application;

FIG. 8 is a diagram of a network architecture provided by an embodiment of the present application;

fig. 9 is a fourth flowchart illustrating a transmission method of an MBS service according to an embodiment of the present application;

fig. 10 is a fifth flowchart illustrating a transmission method of an MBS service according to an embodiment of the present application;

fig. 11 is a sixth flowchart illustrating a MBS service transmission method according to an embodiment of the present application;

fig. 12 is a first schematic structural diagram of a transmission apparatus for MBS service provided in an embodiment of the present application;

fig. 13 is a schematic structural diagram of a transmission apparatus for MBS service according to an embodiment of the present application;

fig. 14 is a schematic structural diagram of a transmission apparatus for MBS service provided in the embodiment of the present application;

fig. 15 is a schematic structural diagram of a communication device according to an embodiment of the present application;

FIG. 16 is a schematic structural diagram of a chip of an embodiment of the present application;

fig. 17 is a schematic block diagram of a communication system according to an embodiment of the present application.

Detailed Description

Technical solutions in the embodiments of the present application will be described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

The technical scheme of the embodiment of the application can be applied to various communication systems, for example: a Long Term Evolution (LTE) system, an LTE Frequency Division Duplex (FDD) system, an LTE Time Division Duplex (TDD) system, a 5G communication system, a future communication system, or the like.

Illustratively, a communication system 100 applied in the embodiment of the present application is shown in fig. 1. The communication system 100 may include a network device 110, and the network device 110 may be a device that communicates with a terminal 120 (or referred to as a communication terminal, a terminal). Network device 110 may provide communication coverage for a particular geographic area and may communicate with terminals located within the coverage area. Optionally, the Network device 110 may be an evolved Node B (eNB or eNodeB) in an LTE system, or a wireless controller in a Cloud Radio Access Network (CRAN), or the Network device may be a mobile switching center, a relay station, an Access point, a vehicle-mounted device, a wearable device, a hub, a switch, a bridge, a router, a Network-side device in a 5G Network, or a Network device in a future communication system, and the like.

The communication system 100 further comprises at least one terminal 120 located within the coverage area of the network device 110. As used herein, "terminal" includes, but is not limited to, a connection via a wireline, such as via a Public Switched Telephone Network (PSTN), a Digital Subscriber Line (DSL), a Digital cable, a direct cable connection; and/or another data connection/network; and/or via a Wireless interface, e.g., for a cellular Network, a Wireless Local Area Network (WLAN), a digital television Network such as a DVB-H Network, a satellite Network, an AM-FM broadcast transmitter; and/or means of another terminal arranged to receive/transmit communication signals; and/or Internet of Things (IoT) devices. A terminal that is arranged to communicate over a wireless interface may be referred to as a "wireless communication terminal", "wireless terminal", or "mobile terminal". Examples of mobile terminals include, but are not limited to, satellite or cellular telephones; personal Communications Systems (PCS) terminals that may combine cellular radiotelephones with data processing, facsimile, and data Communications capabilities; PDAs that may include radiotelephones, pagers, internet/intranet access, web browsers, notepads, calendars, and/or Global Positioning System (GPS) receivers; and conventional laptop and/or palmtop receivers or other electronic devices that include a radiotelephone transceiver. A terminal can refer to an access terminal, user Equipment (UE), subscriber unit, subscriber station, mobile station, remote terminal, mobile device, user terminal, wireless communication device, user agent, or User Equipment. An access terminal may be a cellular telephone, a cordless telephone, a Session Initiation Protocol (SIP) phone, a Wireless Local Loop (WLL) station, a Personal Digital Assistant (PDA), a handheld device having Wireless communication capabilities, a computing device or other processing device connected to a Wireless modem, a vehicle mounted device, a wearable device, a terminal in a 5G network, or a terminal in a future evolved PLMN, etc.

Optionally, the terminals 120 may perform direct-to-Device (D2D) communication therebetween.

Alternatively, the 5G communication system or the 5G network may also be referred to as a New Radio (NR) system or an NR network.

Fig. 1 exemplarily shows one network device and two terminals, and optionally, the communication system 100 may include a plurality of network devices and may include other numbers of terminals within the coverage of each network device, which is not limited in this embodiment of the present application.

Optionally, the communication system 100 may further include other network entities such as a network controller, a mobility management entity, and the like, which is not limited in this embodiment.

It should be understood that a device having a communication function in a network/system in the embodiments of the present application may be referred to as a communication device. Taking the communication system 100 shown in fig. 1 as an example, the communication device may include a network device 110 and a terminal 120 having a communication function, and the network device 110 and the terminal 120 may be the specific devices described above and are not described again here; the communication device may also include other devices in the communication system 100, such as other network entities, for example, a network controller, a mobility management entity, and the like, which is not limited in this embodiment.

It should be understood that the terms "system" and "network" are often used interchangeably herein. The term "and/or" herein is merely an association describing an associated object, meaning that three relationships may exist, e.g., a and/or B, may mean: a exists alone, A and B exist simultaneously, and B exists alone. In addition, the character "/" herein generally indicates that the former and latter related objects are in an "or" relationship.

In order to facilitate understanding of the technical solutions of the embodiments of the present application, the technical solutions related to the embodiments of the present application are described below.

With the pursuit of speed, delay, high-speed mobility, energy efficiency and the diversity and complexity of the services in future life, the third generation partnership project (3) ^rd Generation Partnership Project,3 GPP) international standards organization began to develop 5G. The main application scenarios of 5G are: enhanced Mobile Ultra wide band (eMBB), low-Latency high-reliability communication (URLLC), and massive Machine-Type communication (mMTC).

On the one hand, the eMBB still targets users to obtain multimedia content, services and data, and its demand is growing very rapidly. On the other hand, because the eMBB may be deployed in different scenarios, such as indoor, urban, rural, etc., and the difference between the capabilities and the requirements is relatively large, it cannot be said that it must be analyzed in detail in conjunction with a specific deployment scenario. Typical applications of URLLC include: industrial automation, electric power automation, remote medical operation (surgery), traffic safety, and the like. Typical characteristics of mtc include: high connection density, small data volume, insensitive time delay service, low cost and long service life of the module, etc.

When NR is deployed early, complete NR coverage is difficult to obtain, so typical network coverage is wide area LTE coverage and islanding coverage mode of NR. Moreover, a large amount of LTE is deployed below 6GHz, and the spectrum below 6GHz available for 5G is rare. NR must therefore be studied for spectrum applications above 6GHz, with limited high band coverage and fast signal fading. Meanwhile, in order to protect the early LTE investment of a mobile operator, a light interworking (TIGHT) working mode between LTE and NR is provided.

RRC state

5G defines a new Radio Resource Control (RRC) state, that is, an RRC INACTIVE (RRC _ INACTIVE) state, for the purpose of reducing air interface signaling, quickly recovering Radio connection, and quickly recovering data service. This state is distinguished from the RRC IDLE (RRC IDLE) state and the RRC ACTIVE (RRC ACTIVE) state. Wherein,

1) RRC _ IDLE state (IDLE state for short): the mobility is cell selection and reselection based on terminal equipment, paging is initiated by a Core Network (CN), and a paging area is configured by the CN. The base station side has no terminal equipment context and has no RRC connection.

2) RRC _ CONNECTED state (CONNECTED state for short): the RRC connection exists, and the base station side and the terminal device side have a terminal device context. The network side knows that the location of the terminal device is at a particular cell level. Mobility is network side controlled mobility. Unicast data may be transmitted between the terminal device and the base station.

3) RRC _ INACTIVE state (INACTIVE state for short): mobility is based on cell selection reselection of terminal equipment, connection between CN-NR exists, context of the terminal equipment exists on a certain base station, paging is triggered by RAN, a paging area based on the RAN is managed by the RAN, and the network side knows that the position of the terminal equipment is based on the paging area level of the RAN.

MBMS

MBMS is a technology for transmitting data from one data source to a plurality of terminal equipments by sharing network resources, which enables to provide multimedia services while efficiently utilizing network resources to realize broadcasting and multicasting of the multimedia services at a higher rate (e.g. 256 kbps).

Because the MBMS spectrum efficiency is low, it is not enough to effectively carry and support the operation of the mobile tv type service. Therefore, in LTE, 3GPP explicitly proposes to enhance the support capability for downlink high-speed MBMS services, and determines the design requirements for the physical layer and air interface.

The 3GPP R9 introduces evolved MBMS (eMBMS) into LTE. eMBMS proposes a Single Frequency Network (SFN) concept, that is, a Multimedia Broadcast multicast service Single Frequency Network (MBSFN), where MBSFN employs a uniform Frequency to simultaneously transmit service data in all cells, but needs to ensure synchronization between the cells. The method can greatly improve the distribution of the overall signal-to-noise ratio of the cell, and the frequency spectrum efficiency can be correspondingly and greatly improved. eMBMS implements broadcast and multicast of services based on IP multicast protocol.

In LTE or LTE-Advanced (LTE-a), MBMS has only a broadcast bearer mode and no multicast bearer mode. In addition, the reception of the MBMS service is applicable to terminal devices in an idle state or a connected state.

A Single Cell Point To multipoint (SC-PTM) concept is introduced into a 3GPP R13, and the SC-PTM is based on an MBMS network architecture.

MBMS introduces new logical channels including a Single Cell-Multicast Control Channel (SC-MCCH) and a Single Cell-Multicast Transport Channel (SC-MTCH). The SC-MCCH and SC-MTCH are mapped to a Downlink-Shared Channel (DL-SCH), and the DL-SCH is further mapped to a Physical Downlink Shared Channel (PDSCH), wherein the SC-MCCH and SC-MTCH belong to a logical Channel, the DL-SCH belongs to a transport Channel, and the PDSCH belongs to a Physical Channel. The SC-MCCH and SC-MTCH do not support Hybrid Automatic Repeat reQuest (HARQ) operation.

MBMS introduces a new System Information Block (SIB) type, SIB20. Specifically, configuration information of the SC-MCCH is transmitted through the SIB20, and one cell has only one SC-MCCH. The configuration information of the SC-MCCH comprises: the modification period of the SC-MCCH, the repetition period of the SC-MCCH, and the scheduling of the wireless frame and the subframe of the SC-MCCH. Further, 1) the boundary of the modification period of the SC-MCCH satisfies SFN mod m =0, where SFN represents the system frame number of the boundary, and m is the modification period of the SC-MCCH configured in SIB20 (i.e., SC-MCCH-modification period). 2) And scheduling the radio frame of the SC-MCCH to meet the following requirements: SFN mod MCCH-RepetitionPeriod = MCCH-Offset, where SFN represents a system frame number of a radio frame, MCCH-RepetitionPeriod represents a repetition period of an SC-MCCH, and MCCH-Offset represents an Offset of the SC-MCCH. 3) And the sub-frame for scheduling the SC-MCCH is indicated by SC-MCCH-Subframe.

The SC-MCCH is scheduled through a Physical Downlink Control Channel (PDCCH). On one hand, a new Radio Network Temporary Identity (RNTI), that is, a Single Cell RNTI (SC-RNTI) is introduced to identify a PDCCH (such as SC-MCCH PDCCH) for scheduling an SC-MCCH, and optionally, the SC-RNTI is fixedly valued as FFFC. On the other hand, a new RNTI, namely a Single Cell Notification RNTI (SC-N-RNTI) is introduced to identify a PDCCH (e.g., notification PDCCH) for indicating a change Notification of the SC-MCCH, and optionally, the SC-N-RNTI is fixedly valued as FFFB; further, the change notification may be indicated by one bit of 8 bits (bits) of the DCI 1C. In LTE, the configuration information of SC-PTM is based on SC-MCCH configured by SIB20, and then SC-MCCH configures SC-MTCH which is used for transmitting service data.

Specifically, the SC-MCCH transmits only one message (i.e., SCPTMConfiguration) for configuring configuration information of the SC-PTM. The configuration information of SC-PTM includes: temporary Mobile Group Identity (TMGI), session Identity (session id), group RNTI (G-RNTI), discontinuous Reception (DRX) configuration information, SC-PTM service information of the neighbor cell, and the like. It should be noted that SC-PTM in R13 does not support Robust Header Compression (ROHC) function.

The downlink discontinuous reception of SC-PTMs is controlled by the following parameters: ondurationTimerSCPTM, drx-InactivetTimeSCPTM, SC-MTCH-SchedulingCycle, and SC-MTCH-SchedulingOffset.

When [ (SFN x 10) + subframe number ] module (SC-MTCH-scheduling cycle) = SC-MTCH-scheduling offset is satisfied, a timer onDurationTimerSCPTM is started;

when receiving downlink PDCCH dispatching, starting a timer drx-InactivetyTimerSCPTM;

the downlink SC-PTM service is received only when the timer onDurationTimerSCPTM or drx-inactivityttimerscptm is running.

SC-PTM service continuity adopts SIB 15-based MBMS service continuity concept, namely SIB15+ MBMSIntestrIndication mode. The service continuity of the terminal device in the idle state is based on the concept of frequency priority.

In the technical solution of the embodiment of the present application, a new SIB (referred to as a first SIB) is defined, where the first SIB includes configuration information of a first MCCH, where the first MCCH is a control channel of an MBMS service, in other words, the first SIB is used to configure configuration information of a control channel of an NR MBMS, and optionally, the control channel of the NR MBMS may also be referred to as an NR MCCH (i.e., the first MCCH).

Further, the first MCCH is used to carry a first signaling, and in this embodiment of the present application, the name of the first signaling is not limited, for example, the first signaling is signaling a, the first signaling includes configuration information of at least one first MTCH, where the first MTCH is a traffic channel (also referred to as a data channel or a transport channel) of an MBMS service, and the first MTCH is used to transmit MBMS service data (e.g., service data of NR MBMS). In other words, the first MCCH is used to configure configuration information of a traffic channel of the NR MBMS, which may also be called NR MTCH (i.e., the first MTCH) optionally.

Specifically, the first signaling is used to configure a service channel of the NR MBMS, service information corresponding to the service channel, and scheduling information corresponding to the service channel. Further, optionally, the service information corresponding to the service channel, for example, the identification information for identifying the service, such as the TMGI, the session id, and the like. The scheduling information corresponding to the traffic channel, for example, the RNTI used when the MBMS service data corresponding to the traffic channel is scheduled, for example, G-RNTI, DRX configuration information, and the like.

It should be noted that the transmission of the first MCCH and the first MTCH is scheduled based on the PDCCH. Wherein, the RNTI used by the PDCCH for scheduling the first MCCH uses a network-wide unique identifier, which is a fixed value. The RNTI used by the PDCCH for scheduling the first MTCH is configured through the first MCCH.

It should be noted that, in the embodiment of the present application, naming of the first SIB, the first MCCH, and the first MTCH is not limited. For convenience of description, the first SIB may also be abbreviated as SIB, the first MCCH may also be abbreviated as MCCH, the first MTCH may also be abbreviated as MTCH, and a PDCCH for scheduling MCCH (i.e., MCCH PDCCH) and a notification PDCCH are configured through SIB, wherein PDSCH for transmitting MCCH (i.e., MCCH PDSCH) is scheduled through DCI carried by MCCH PDCCH. Further, M PDCCHs for scheduling MTCHs (i.e., MTCH 1 PDCCH, MTCH 2 PDCCH, …, MTCH M PDCCH) are configured through the MCCH, wherein DCI carried by the MTCH n PDCCH schedules a PDSCH for transmitting MTCH n (i.e., MTCH n PDSCH), n being an integer of 1 or more and M or less. The MCCH and MTCH are mapped to DL-SCH, which belongs to a logical channel, and further mapped to PDSCH, which belongs to a physical channel.

It should be noted that the MBMS service in the above scheme includes, but is not limited to, a multicast service and a multicast service. In the embodiment of the present application, MBS service is taken as an example for explanation, and the description of "MBS service" may also be replaced by "multicast service" or "MBMS service".

In the NR MBS service, besides that the same cell needs to send the MBS service in multicast transmission, it may also transmit the MBS service in unicast for a specific user, for example, when the channel of the user is poor, the MBS service needs to be transmitted in unicast for the user. In a cell, there may also be several users receiving a certain MBS service at the same time, but the base station sends the MBS service to each user in a unicast manner, for example, the efficiency of service transmission can be effectively improved by sending the MBS service to each user in a unicast manner when there are fewer users receiving the MBS service in the cell.

Referring to fig. 2, for a Packet Data Unit (PDU) session of a certain MBS service, a Shared GTP tunnel (Shared GTP tunnel) may be used between a 5G Core network (5G Core network,5 gc) and a gNB to transmit the MBS service, that is, the MBS service in both unicast and multicast modes shares the GTP tunnel. The gNB issues the MBS service to a multicast group (multicast group) in a multicast (multicast) manner, and issues the MBS service to a certain UE in a unicast (unicast) manner (fig. 2 takes UE3 as an example). Wherein, the multicast group includes one or more UEs (fig. 2 takes the example that the multicast group includes UE1 and UE 2).

In view of the mobility of the terminal device, a scenario may arise in which the terminal device is handed over from one cell to another. As shown in fig. 3, UE1 receives MBS service sent by gNB1 in multicast mode in the first cell, and after UE1 switches from cell 1 to cell 2, receives MBS service sent by gNB2 in multicast mode in the second cell. Different base stations (such as the gNB1 and the gNB 2) may have time differences for the transmission of the MBS service, that is, the MBS services transmitted by different base stations are not synchronous, for example, the MBS service transmitted by the gNB1 is earlier or later than the MBS service transmitted by the gNB2, that is, the same MBS service is earlier or later at the transmission time of different gnbs, so how to ensure the continuity of the MBS service in the handover process is a problem that needs to be clear. Therefore, the following technical scheme of the embodiment of the application is provided.

Fig. 4 is a first flowchart illustrating a transmission method of an MBS service provided in an embodiment of the present application, where as shown in fig. 4, the transmission method of the MBS service includes the following steps:

step 401: the target base station receives the MBS service data forwarded by the original base station, and the target base station sends the MBS service data forwarded by the original base station to the terminal equipment in a unicast mode.

In the embodiment of the present application, in consideration of a mobility scenario of a terminal device, the terminal device may be handed over from one base station (i.e., an original base station) to another base station (i.e., a target base station). For example: the original base station is original gNB (Source gNB), and the Target base station is Target gNB (Target gNB).

In the embodiment of the application, the MBS service data of the original base station side is sent to the original base station by a core network through a first tunnel, and the MBS service data of the target base station side is sent to the target base station by the core network through a second tunnel. That is, the original base station receives MBS service data sent by the core network through the first tunnel, and issues the MBS service data in a unicast and/or multicast manner. And the target base station receives the MBS service data sent by the core network through the second tunnel and issues the MBS service data in a unicast and/or multicast mode. The MBS service data of the original base station side and the MBS service data of the target base station side are asynchronous.

In the embodiment of the present application, before the switching, the terminal device may receive MBS service data sent by an original base station in a multicast mode or a unicast mode.

In this embodiment of the present application, before the target base station receives MBS service data forwarded by an original base station, the method further includes:

the target base station receives a HANDOVER REQUEST (HANDOVER REQUEST) message sent by the original base station, wherein the HANDOVER REQUEST message carries relevant information of a first MBS service, and the first MBS service refers to an MBS service received by the terminal equipment at the original base station;

the target base station sends a HANDOVER REQUEST acknowledgement (HANDOVER ACKNOWLEDGE) message to the original base station, wherein the HANDOVER REQUEST acknowledgement message carries a first tunnel identifier, and the first tunnel identifier is used for the original base station to forward MBS service data to the target base station.

In the foregoing solution, optionally, the related information of the first MBS service includes at least one of the following: service identification, session identification, physical channel configuration information and logical channel configuration information.

Here, the service identifier may be, for example, MBS TMGI of MBS service.

Here, the session identifier refers to an MBS session identifier (MBS session id) of the MBS service.

Here, the physical channel configuration information refers to configuration information of an MBS physical channel of the MBS service.

Here, the logical channel configuration information refers to configuration information of MBS logical channel configuration of the MBS service.

In the above scheme, the first tunnel identifier is allocated to the original base station by the target base station side, and is used for the original base station to forward MBS service data to the target base station. Optionally, the first tunnel identification is a GTP tunnel identification (GTP TEID).

In the embodiment of the application, the original base station forwards MBS service data to the target base station based on the first tunnel identifier, and sends a handover Command (HO-Command) to the terminal device. Here, it should be noted that the step of the original base station forwarding the MBS service data to the target base station and the step of sending the handover command to the terminal device do not limit the execution order.

In the embodiment of the present application, the receiving, by the target base station, MBS service data forwarded by the original base station may be:

i) The target base station receives a Packet Data Convergence Protocol (PDCP) Service Data Unit (SDU) and a Serial Number (SN) forwarded by an original base station, wherein the PDCP SDU carries MBS Service Data; or,

ii) the target base station receives a PDCP Protocol Data Unit (PDU) forwarded by the original base station, wherein the PDCP PDU carries SN and MBS service Data; or,

iii) The target base station receives an IP data packet and an SN forwarded by an original base station, wherein the IP data packet carries MBS service data; or,

iv) the target base station receives Service Data Adaptation Protocol (SDAP) SDU and SN forwarded by the original base station, wherein the SDAP SDU carries MBS Service Data.

v) the target base station receives the IP data packet forwarded by the original base station, wherein the IP data packet carries MBS service data.

In the embodiment of the application, for a scenario that MBS service data forwarded by an original base station to a target base station is an IP data packet, the target base station transmits the MBS service data forwarded by the original base station to a terminal device in a unicast manner, and at this time, the target base station performs the following processing on the MBS service data transmitted to the terminal device:

1) And the target base station adds PDCP SN to the MBS service data forwarded from the original base station, and the PDCP SN is determined based on the PDCP SN of the MBS service data transmitted in a multicast mode. Optionally, the added PDCP SN is determined based on the PDCP SN of the first MBS service data transmitted to the terminal device in a multicast manner and the total number of the forwarded MBS service data. For example: if the target base station expects the terminal device to receive n PDCP SNs of the first MBS data in the multicast mode and m forwarded MBS data waiting for unicast mode transmission, the PDCP SNs of the MBS data transmitted in the unicast mode are sequentially n-m, n-m +1 … … n-1, and the target base station will sequentially add these PDCP SNs to the MBS data corresponding to the unicast mode. At this time, the receiving window of the terminal device is not reset in the switching process. Or,

2) And the target base station adds PDCP SN to the MBS service data forwarded from the original base station, and the PDCP SN is set from an initial value. Here, the time when the target base station sends the first indication information to the terminal device is located after a first time and before a second time, the first time refers to a time when the terminal device finishes receiving MBS service data in a unicast mode, and the second time refers to a time when the terminal device starts receiving MBS service data in a multicast mode. Specifically, after the MBS service data transmission in the unicast mode and before the terminal device receives the MBS service data in the multicast mode, the target base station issues the indication information to tell the terminal device to reset the receive window, and optionally, may also tell the terminal device about the size of the initial value of the variable of the receive window.

In the embodiment of the application, after receiving the MBS service data forwarded by the original base station, the target base station may determine whether to trigger the original base station to stop forwarding the MBS service data in one of the following manners.

The first method is as follows: the target base station judges whether the MBS service data forwarded by the original base station is transmitted on an air interface of the target base station side; and if the MBS service data forwarded by the original base station is not transmitted on the air interface of the target base station side, the target base station sends second indication information to the original base station, wherein the second indication information is used for indicating the original base station to stop forwarding the MBS service data continuously.

The second method comprises the following steps: the target base station judges whether MBS service data forwarded by the original base station exists in a memory of the target base station; if the memory of the target base station has the MBS service data forwarded by the original base station, the target base station sends second indication information to the original base station, and the second indication information is used for indicating the original base station to stop forwarding the MBS service data continuously.

Step 402: and the target base station sends first indication information to the terminal equipment, wherein the first indication information is used for indicating the terminal equipment to reset a receiving window, and the reset receiving window is used for receiving the MBS service data sent by the target base station by the terminal equipment in a multicast mode.

In the embodiment of the application, after receiving the handover command sent by the original base station, the terminal device switches from the original base station to the target base station, that is, initiates a random access process to the target base station. The terminal equipment sends a handover Complete (HO Complete) message to a target base station, and the target base station sends MBS service data forwarded by the original base station to the terminal equipment in a unicast mode after receiving the handover Complete message sent by the terminal equipment. And then, the target base station sends first indication information to the terminal equipment, wherein the first indication information is used for indicating the terminal equipment to reset a receiving window, and further, the first indication information is also used for indicating the terminal equipment to update the value of at least one variable of the reset receiving window to a default value.

Optionally, the first indication information is further used to indicate that the terminal device delivers all PDCP SDUs in the receive window before the reset to a higher layer.

It should be noted that the receiving window before resetting is used for the terminal device to receive the MBS service data of the original base station side, where the MBS service data of the original base station side includes MBS service data sent by the original base station and/or MBS service data forwarded by the target base station from the original base station. And the reset receiving window is used for receiving the MBS service data sent by the target base station by the terminal equipment according to a multicast mode.

Referring to fig. 5-1, the receiving window before the terminal device receives the first indication information is the receiving window before resetting. Referring to fig. 5-2, the receiving window after the terminal device receives the first indication information is the reset receiving window. Wherein the at least one variable of the receive window comprises at least one of:

RX _ DELIV for indicating a COUNT value associated with the first MBS service data not yet delivered to the upper layer in the reception window, the COUNT value being determined based on the SN.

RX _ REORD, the variable indicating a COUNT value corresponding to MBS service data starting a t-Reordering timer in a reception window, the COUNT value being determined based on the SN.

RX _ Next, which is used to indicate a COUNT value corresponding to the Next MBS service data expected to be received, and the COUNT value is determined based on the SN.

In this embodiment of the application, the first indication information indicates that the terminal device updates a value of the at least one variable of the reset receiving window to a default value, and the following implementation manner may be adopted:

mode a) the default value is a set initial value, for example 0. And the first indication information indicates the terminal equipment to update the value of at least one variable of the reset receiving window to an initial value.

Mode b) the default value is indicated by the first indication information display. And the first indication information indicates the terminal equipment to update the value of at least one variable of the reset receiving window to a given default value.

In this embodiment of the application, the first indication information is carried in a Media Access Control Element (MAC CE), or in a PDCCH, or in an RRC signaling.

In the embodiment of the application, after the terminal device receives the first indication information and resets the receiving window, the terminal device receives the MBS service data sent by the target base station in the multicast mode based on the reset receiving window, and thus, the terminal device can receive the MBS service data of the target base station from the target base station.

In the embodiment of the present application, the receiving window in the above scheme refers to a receiving window of a PDCP layer.

Fig. 6 is a flowchart illustrating a second method for transmitting MBS services provided in an embodiment of the present application, where a UE corresponds to a terminal device in the embodiment of the present application, and as shown in fig. 6, the method for transmitting MBS services includes the following steps:

and the UE is in an RRC (radio resource control) connected state at the original base station and receives MBS service data transmitted by the original base station on an air interface in a unicast mode or a multicast mode. Wherein, the GTP tunnel from the core network (e.g., UPF) to the original base station for transmitting MBS service data may be a shared GTP tunnel (i.e., shared GTP tunnel 1) or a UE-specific GTP tunnel (i.e., unicast GTP tunnel). The shared GTP tunnel means that MBS service data of an MBS service is transmitted from the UPF to the base station, and the MBS service data is transmitted on the air interface in a unicast mode and a multicast mode at the base station respectively.

Step 601: the original base station makes decision switching and sends a switching request message to the target base station, wherein the switching request message carries the related information of the MBS service which is being received by the UE in the original cell.

Here, optionally, the original base station may make a decision for handover based on the measurement result reported by the UE.

Here, optionally, the related information of the MBS service being received by the UE in the original cell includes at least one of the following: MBS TMGI, MBS session id, configuration information of MBS physical channel and configuration information of MBS logical channel.

Step 602: and the target base station replies a switching confirmation message which carries a GTP tunnel identifier which is distributed by the target base station and used for the original base station to forward the MBS service data to the target base station.

Step 603.1: and the original base station forwards the MBS service data to the target base station on the GTP tunnel indicated by the GTP tunnel identifier.

Here, the MBS service data forwarded on the GTP tunnel may be: PDCP SDU + SN, or PDCP PDU, or IP packet + SN, or SDAP SDU + SN, or IP packet. The PDCP SDU carries MBS service data, the PDCP PDU carries MBS service data and SN, the IP data packet carries MBS service data, and the SDAP SDU carries MBS service data.

In the embodiment of the application, for a scenario that MBS service data forwarded by an original base station to a target base station is an IP data packet, the target base station transmits the MBS service data forwarded by the original base station to a UE in a unicast manner, and at this time, the target base station performs the following processing on the MBS service data transmitted to the UE:

1) And the target base station adds PDCP SN to the MBS service data forwarded from the original base station, and the PDCP SN is determined based on the PDCP SN of the MBS service data transmitted in a multicast mode. For example: if the target base station expects that the UE receives n PDCP SNs of the first MBS service data in the multicast mode and m forwarded MBS service data waiting for being transmitted in the unicast mode, the PDCP SNs of the MBS service data transmitted in the unicast mode are n-m and n-m +1 … … n-1 in sequence, and the target base station can add the PDCP SNs to the MBS service data corresponding to the unicast mode in sequence. At this time, the reception window of the UE is not reset during the handover process. Or,

2) And the target base station adds PDCP SN to the MBS service data forwarded from the original base station, and the PDCP SN is set from an initial value. After the unicast MBS service data is transmitted and before the UE receives the multicast MBS service data, the target base station sends indication information to tell the UE to reset the receiving window, optionally, the target base station can also tell the UE about the size of the initial value of the variable of the receiving window.

Step 603.2: and the original base station sends a switching command to the UE.

Here, the handover command is an RRC reconfiguration (RRCReconfiguration) message in the NR system.

It should be noted that step 603.1 and step 603.2 do not limit the order.

Step 604: the target base station caches the MBS service data forwarded by the original base station and judges whether the forwarded MBS service data is transmitted on an air interface of the target base station or whether the MBS service data exists in a memory of the target base station; if the forwarded MBS service data is not transmitted on the empty port of the target base station or the MBS service data exists in the memory of the target base station, the target base station determines that the original base station stops forwarding the MBS service data.

Step 605: the target base station sends an indication message to the original base station, and the indication message is used for indicating the original base station to stop forwarding the MBS service data.

Step 606: and the UE initiates a random access process to the target base station after receiving the switching command and sends a switching completion message to the target base station.

Here, in the NR system, the handover complete message is an RRC reconfiguration complete (rrcreeconfigurationcomplete) message.

In the switching process of the UE, the receiving window and the variables thereof of the PDCP layer are kept the same as before the switching, and the receiving window and/or the variables of the receiving window are not reset until the UE receives new MBS service data at the target base station side. That is, the receive window and the variables of the receive window are not reset or changed during the handover.

Step 607: the target base station sends the MBS service data forwarded by the original base station to the UE according to a unicast mode, and the UE receives the MBS service data sent by the target base station according to the unicast mode.

Step 608: if the target base station sends the MBS service data which is transmitted by the original base station, the target base station sends an indication message to the UE, the indication message is used for indicating the UE to submit all PDCP SDUs in the receiving window to a high layer, and the values of the receiving window and the variable of the receiving window are reset.

Here, optionally, the value of the variable of the receiving window is given in the indication information or is a default value.

Here, optionally, the indication information may be carried in a MAC CE, or in a PDCCH, or in RRC signaling. If carried in a MAC CE, the protocol defines the logical channel ID (i.e., LCID) of that MAC CE to identify that MAC CE.

After receiving the indication information, the UE submits all PDCP SDUs in the receiving window to a high layer and resets the values of variables of the receiving window and the receiving window.

Step 609: and after receiving the indication information, the UE starts to receive the MBS service data sent by the target base station in a multicast mode.

In the technical scheme of the embodiment of the application, in the mobility process, the target base station judges the stop condition of the MBS service data forwarding, so that the forwarding and stopping of the MBS service data are triggered. The target base station controls the UE to reset the receiving window to realize the continuity and reliability of service reception.

Fig. 7 is a third flowchart illustrating a MBS service transmission method provided in an embodiment of the present application, where as shown in fig. 7, the MBS service transmission method includes the following steps:

step 701: an original base station sends first auxiliary information to a target base station, wherein the first auxiliary information is used for the target base station to determine whether the original base station needs to forward MBS service data to the target base station.

In the embodiment of the present application, in consideration of a mobility scenario of a terminal device, the terminal device may be handed over from one base station (i.e., an original base station) to another base station (i.e., a target base station). For example: the original base station is an original gNB (Source gNB), and the Target base station is a Target gNB (Target gNB).

In the embodiment of the application, the MBS service data of the original base station side is sent to the original base station by a core network through a first tunnel, and the MBS service data of the target base station side is sent to the target base station by the original base station through a second tunnel. That is, the original base station receives MBS service data sent by the core network through the first tunnel, and issues the MBS service data in a unicast and/or multicast manner. And the target base station receives the MBS service data from the core network forwarded by the original base station through the second tunnel, and issues the MBS service data in a unicast and/or multicast mode. The MBS service data of the original base station side and the MBS service data of the target base station side are asynchronous.

In this embodiment, the original base station and the target base station may adopt one of the following network architectures:

1) The DU and CU integration architecture includes an original base station and a target base station, and specifically, the original base station and the target base station have independent total protocol stacks, where the total protocol stacks include a first protocol stack and a second protocol stack, where the first protocol stack refers to a protocol stack corresponding to the DU and the second protocol stack refers to a protocol stack corresponding to the CU.

Here, the protocol stack corresponding to the DU includes an RLC layer, an MAC layer, and a PHY layer. The protocol stack corresponding to the CU comprises an SDAP layer and a PDCP layer.

Referring to fig. 8, the original base station has a set of total protocol stacks: SDAP layer, PDCP layer, RLC layer, MAC layer, PHY layer. The target base station also has a set of total protocol stacks: the SDAP layer, the PDCP layer, the RLC layer, the MAC layer, and the PHY layer (the SDAP layer and the PDCP layer on the target base station side are not illustrated in FIG. 8). The total protocol stack of the original base station and the target base station of the target base station are independent. After receiving the MBS service data sent by the core network, the original base station copies a copy of RLC layer sent to the target base station through the PDCP layer, and the original MBS service data is sent to the RLC layer of the original base station.

2) The Distribution Unit (DU) and the Collection Unit (CU) are separated by a framework, and specifically, the original base station and the target base station have independent first protocol stacks and a shared second protocol stack, where the first protocol stack refers to a protocol stack corresponding to the distribution unit DU and the second protocol stack refers to a protocol stack corresponding to the collection unit CU.

Here, the protocol stack corresponding to the DU includes an RLC layer, an MAC layer, and a PHY layer. The protocol stack corresponding to the CU comprises an SDAP layer and a PDCP layer. Compared with a DU and CU integration architecture, an original base station is equivalent to an original DU, a target base station is equivalent to a target DU, and the original DU and the target DU are connected with the same CU. Signaling between two base stations is equivalent to signaling between two DUs, and further, signaling between two DUs can be directly transmitted between two DUs or indirectly transmitted through a CU forwarding manner. The following embodiments mostly use the integrated DU and CU architecture as the network background, but the separate DU and CU architectures are also applicable to the technical solution of the embodiments of the present application.

In the embodiment of the application, the original base station sends a handover request message to a target base station, the handover request message carries relevant information of a first MBS service and the first auxiliary information, and the first MBS service refers to an MBS service received by the terminal device at the original base station.

Here, the service identifier may be, for example, MBS TMGI of MBS service.

In the above solution, the first auxiliary information is used to determine a first PDCP SN, where the first PDCP SN is a PDCP SN of the last MBS service data sent by the original base station to the terminal device or a PDCP SN of the next MBS service data to be sent.

In the embodiment of the application, after receiving the first auxiliary information forwarded by the original base station, the target base station may determine whether the original base station needs to forward MBS service data in one of the following manners.

The first method is as follows: the first PDCP SN and the PDCP SN of the MBS service data existing in the memory of the target base station are used for the target base station to determine whether the original base station is needed to transmit the MBS service data to the target base station.

The second method comprises the following steps: the first PDCP SN and the PDCP SN of the MBS service data which is sent by the target base station are used for the target base station to determine whether the original base station is needed to forward the MBS service data to the target base station.

Specifically, the target base station may determine whether MBS service data corresponding to the first PDCP SN has been sent at the target base station side according to the first PDCP SN and the PDCP SN of MBS service data existing in a memory of the target base station or the PDCP SN of MBS service data being sent by the target base station, and if not, determine that the original base station is not required to forward the MBS service data to the target base station; if the MBS data is sent, the original base station is determined to be needed to transmit the MBS service data to the target base station. Here, whether MBS service data corresponding to the first PDCP SN has been transmitted on the target base station side may be determined based on the following manner: and if the first PDCP SN is less than or equal to the PDCP SN of the MBS service data existing in the memory of the target base station or the PDCP SN of the MBS service data being sent by the target base station, determining that the MBS service data corresponding to the first PDCP SN is already sent by the target base station side. And if the first PDCP SN is larger than or equal to the PDCP SN of the MBS service data existing in the memory of the target base station or the PDCP SN of the MBS service data being sent by the target base station, determining that the MBS service data corresponding to the first PDCP SN is not sent at the side of the target base station.

Further, in an optional manner, the first PDCP SN and the PDCP SN of the MBS service data being sent by the target base station are used by the target base station to determine a first PDCP SN list of the MBS service data forwarded to the target base station by the original base station.

For example: and forming a first PDCP SN list by the PDCP SNs between the PDCP SNs of the MBS service data which is sent by the target base station and the first PDCP SNs.

Step 702: and the source base station receives third indication information sent by the target base station, wherein the third indication information is used for indicating the source base station to forward MBS service data to the target base station.

In the embodiment of the application, the original base station receives a switching request confirmation message sent by the target base station; and when the original base station is required to forward the MBS service data to the target base station, the switching request confirmation message carries a first tunnel identifier, and the first tunnel identifier is used for the original base station to forward the MBS service data to the target base station.

It should be noted that, the first tunnel identifier may also implicitly instruct the source base station to forward MBS service data to the target base station. I.e. the first tunnel identification may be interpreted as third indication information. Or, the handover request acknowledgement message carries an explicit third indication information, where the third indication information is used to indicate the source base station to forward MBS service data to the target base station.

Further, optionally, the handover request acknowledgement message further carries fourth indication information, where the fourth indication information is used to indicate a first PDCP SN list or a first quantity, where the first quantity and the first PDCP SN are used to determine the first PDCP SN list, and the first PDCP SN list refers to a PDCP SN list of MBS service data forwarded by the original base station to the target base station.

Here, the first PDCP SN of the first PDCP SN list is the first PDCP SN, and the last PDCP SN of the first PDCP SN list is the second PDCP SN. Wherein the second PDCP SN = the first PDCP SN + the first number.

Step 703: the source base station transmits MBS service data to the target base station and sends a switching command to the terminal equipment, wherein the switching command is used for triggering the terminal equipment to be switched from the original base station to the target base station and receiving the MBS service data sent by the target base station in a unicast mode and the MBS service data sent by the target base station in a multicast mode.

In this embodiment, the source base station forwards MBS service data to the target base station on the tunnel indicated by the first tunnel identifier, where a PDCP SN list of the MBS service data forwarded to the target base station by the original base station is the first PDCP SN list. In addition, the source base station sends a handover command to the terminal device. Here, it should be noted that the step of forwarding the MBS service data to the target base station and the step of sending the handover command to the terminal device by the original base station do not limit the execution sequence.

In the embodiment of the present application, the receiving, by the target base station, MBS service data forwarded by the original base station may be: and the target base station receives the PDCP PDU forwarded by the original base station, wherein the PDCP PDU carries SN and MBS service data.

In this embodiment of the present application, optionally, the handover command carries fifth indication information, where the fifth indication information is used to indicate the terminal device to simultaneously receive MBS service data sent by the target base station in a unicast manner and MBS service data sent by the target base station in a multicast manner.

In the embodiment of the application, after receiving the handover command sent by the original base station, the terminal device switches from the original base station to the target base station, that is, initiates a random access process to the target base station. The terminal device sends a switching completion message to a target base station, and the target base station sends the MBS service data forwarded by the original base station to the terminal device according to a unicast mode after receiving the switching completion message sent by the terminal device, wherein the MBS service data sent by the target base station according to the unicast mode refers to the MBS service data forwarded by the source base station. And the terminal equipment receives the MBS service data sent by the target base station in a unicast mode and the MBS service data sent by the target base station in a multicast mode based on the fifth indication information in the switching command.

It should be noted that, in the handover process, the receiving window and its variables of the PDCP layer are kept the same as those before the handover, and the receiving window and/or its variables are not reset until the terminal receives new MBS service data at the target base station. That is, the receive window and the variables of the receive window are not reset or changed during the handover.

Fig. 9 is a fourth flowchart illustrating a transmission method of an MBS service provided in an embodiment of the present application, where a UE corresponds to a terminal device in the embodiment of the present application, and as shown in fig. 9, the transmission method of the MBS service includes the following steps:

and the UE is in an RRC connection state at the original base station and receives MBS service data sent by the original base station on an air interface in a unicast mode or a multicast mode. Wherein, the GTP tunnel from the core network (e.g., UPF) to the original base station for transmitting MBS service data may be a shared GTP tunnel (i.e., shared GTP tunnel 1) or a UE-specific GTP tunnel (i.e., unicast GTP tunnel). The shared GTP tunnel means that MBS service data of an MBS service is transmitted from the UPF to the base station, and the MBS service data is transmitted on the air interface in a unicast mode and a multicast mode at the base station respectively. Based on the network architecture shown in fig. 8, the original base station forwards MBS service data (i.e., PDCP PDUs) from the core network to the target base station through the GTP tunnel.

Step 901: and the original base station makes a decision on switching and sends a switching request message to the target base station, wherein the switching request message carries the related information of the MBS service which is being received by the UE in the original cell and the first PDCP SN.

Here, the first PDCP SN is a PDCP SN of the last MBS service data received by the UE at the original base station or a PDCP SN of the MBS service data to be received next.

Step 902: and the target base station judges whether the original base station needs to forward the MBS service data or not according to the first PDCP SN.

Specifically, the target base station determines that the MBS service data corresponding to the first PDCP SN is not sent in the target base station according to the first PDCP SN, and the original base station is not required to forward the MBS service data, otherwise, the original base station is required to forward the MBS service data.

And if the target base station judges that the original base station is required to forward the MBS service data, the target base station distributes a GTP tunnel identifier for the original base station to forward the MBS service data to the target base station. Further, the target base station further determines which PDCP SNs (i.e., the first PDCP SN list) need to be forwarded according to the PDCP SNs of the MBS service data in the current memory or the PDCP SNs of the MBS service data currently being sent, or determines how many PDCP SNs (i.e., the first numerical value) after the first PDCP SN are forwarded, corresponding to the MBS service data.

Step 903: and the target base station replies a switching confirmation message which carries a GTP tunnel identifier which is distributed by the target base station and used for the original base station to forward the MBS service data to the target base station.

Further, optionally, the reply handover confirmation message further carries an indication information, where the indication information is used to indicate the PDCP SNs of the MBS service data that needs to be forwarded, for example, N PDCP SNs starting from the first PDCP SN, where N is a positive integer. For example, indicating a PDCP SN list.

Step 904.1: and the original base station forwards the MBS service data to the target base station on the GTP tunnel indicated by the GTP tunnel identifier.

Here, the MBS service data forwarded on the GTP tunnel may be: the PDCP PDU. Wherein, the PDCP PDU carries MBS service data and SN.

Step 904.2: and the original base station sends a switching command to the UE.

Here, the handover command is an RRC reconfiguration (rrcconfiguration) message in the NR system.

It should be noted that, the sequence of step 904.1 and step 9034.2 is not limited.

Further, the switching command carries an indication message, where the indication message is used to indicate the UE to receive the MBS service in unicast and multicast modes at the target base station simultaneously.

Step 905: and the UE initiates a random access process to the target base station after receiving the switching command and sends a switching completion message to the target base station.

Step 906: and the target base station sends the MBS service data forwarded by the original base station to the UE according to a unicast mode.

Step 907: and the target base station sends the MBS service data to the UE according to the multicast mode.

It should be noted that, the step 906 and the step 907 may be executed simultaneously, and the UE receives the MBS service data in the unicast mode and the MBS service data in the multicast mode simultaneously according to the indication information in the handover command.

In the technical scheme of the embodiment of the application, in the mobility process, the target base station judges whether the original base station is triggered to forward the MBS service data and which MBS service data are forwarded based on the assistance of the original base station. Whether the UE receives the MBS service data in the multicast mode and the MBS service data in the unicast mode at the same time is controlled by the network side (namely the original base station) to realize the continuity and reliability of service reception.

Fig. 10 is a flowchart illustrating a fifth method for transmitting MBS services provided in an embodiment of the present application, where as shown in fig. 10, the method for transmitting MBS services includes the following steps:

step 1001: and the terminal equipment receives a switching command sent by the original base station and switches from the source base station to the target base station.

In the embodiment of the present application, before the switching, the terminal device may receive MBS service data sent by an original base station in a multicast manner or a unicast manner.

In the embodiment of the application, before a terminal device receives a handover command sent by an original base station, the original base station sends a handover request message to a target base station, and the handover request message carries relevant information of a first MBS service. And the original base station receives a switching request confirmation message sent by the target base station. And then, the terminal equipment receives the switching command sent by the original base station.

Here, the service identifier may be, for example, MBS TMGI of MBS service.

In the foregoing scheme, optionally, the handover command carries seventh indication information, where the seventh indication information is used to indicate whether the terminal device reports the second PDCP SN list to the target base station, where the second PDCP SN list refers to a missing PDCP SN list between the original base station and the target base station (that is, the missing PDCP SN list is used to determine an SN gap).

Step 1002: and the terminal equipment sends sixth indication information to the target base station, wherein the sixth indication information is used for indicating a second PDCP SN list, and the second PDCP SN list refers to a missing PDCP SN list between the original base station and the target base station.

In the embodiment of the application, after receiving the handover command sent by the original base station, the terminal device switches from the original base station to the target base station, that is, initiates a random access process to the target base station. And the terminal equipment sends a switching completion message to the target base station, wherein the switching completion message carries the sixth indication information, and the sixth indication information is used for indicating a missing PDCP SN list between the original base station and the target base station.

Step 1003: and the terminal equipment receives MBS service data sent by the target base station in a unicast mode and MBS service data sent in a multicast mode.

In the embodiment of the application, after receiving the switching completion message sent by the terminal device, the target base station sends MBS service data to the terminal device in a unicast manner, and simultaneously sends MBS service data to the terminal device in a multicast manner. And the MBS service data sent by the target base station in a unicast mode is determined based on the second PDCP SN list.

It should be noted that, during the handover process, the receiving window and its variables of the PDCP layer are kept the same as before the handover, and the receiving window and/or the variables of the receiving window are not reset until the terminal receives new MBS service data at the target base station. That is, the receive window and the variables of the receive window are not reset or changed during the handover.

In the embodiment of the present application, the receiving window in the above scheme refers to a receiving window of the PDCP layer.

Fig. 11 is a sixth flowchart illustrating a method for transmitting MBS services provided in an embodiment of the present application, where a UE corresponds to a terminal device in the embodiment of the present application, and as shown in fig. 11, the method for transmitting MBS services includes the following steps:

Step 1101: the original base station makes decision switching and sends a switching request message to the target base station, wherein the switching request message carries the related information of the MBS service which is being received by the UE in the original cell.

Step 1102: the target base station replies to the handover confirm message.

Step 1103: and the original base station sends a switching command to the UE.

Further, the handover command carries an indication information, where the indication information is used to indicate whether the UE can report the gap of the PDCP PDU between the original base station and the target base station to the target base station, that is, the missing PDCP SN list between the original base station and the target base station.

Step 1104: and the UE initiates a random access process to the target base station after receiving the switching command and sends a switching completion message to the target base station.

Further, the handover completion message carries an indication information, and the indication information is used for indicating a missing PDCP SN list between the original base station and the target base station.

Step 1105: and the target base station sends the MBS service data corresponding to the missing PDCP SN list to the UE according to a unicast mode.

Step 1106: and the target base station sends the MBS service data to the UE according to the multicast mode.

It should be noted that, step 1105 and step 1106 may be executed simultaneously, and the UE receives the MBS service data in unicast mode and the MBS service data in multicast mode simultaneously.

In the technical scheme of the embodiment of the application, in the mobility process, the UE is controlled to report the missing PDCP SN list based on the network side (namely the original base station), and the target base station is triggered to send the missing MBS service data, so that the continuity and reliability of service receiving are realized.

Fig. 12 is a schematic structural diagram of a transmission apparatus for MBS service provided in an embodiment of the present application, which is applied to a target base station, and the apparatus includes:

a receiving unit 1201, configured to receive MBS service data forwarded by an original base station;

a sending unit 1202, configured to send, according to a unicast manner, MBS service data forwarded by the original base station to a terminal device; and sending first indication information to the terminal equipment, wherein the first indication information is used for indicating the terminal equipment to reset a receiving window, and the reset receiving window is used for receiving MBS service data sent by the target base station by the terminal equipment according to a multicast mode.

In an optional manner, the receiving unit 1201 is further configured to receive a handover request message sent by the original base station, where the handover request message carries related information of a first MBS service, and the first MBS service refers to an MBS service received by the terminal device at the original base station;

the sending unit 1202 is further configured to send a handover request acknowledgement message to the original base station, where the handover request acknowledgement message carries a first tunnel identifier, and the first tunnel identifier is used for the original base station to forward MBS service data to the target base station.

In an optional manner, the related information of the first MBS service includes at least one of: service identification, session identification, physical channel configuration information and logical channel configuration information.

In an optional manner, the receiving unit 1201 is configured to receive a PDCP SDU and an SN forwarded by an original base station, where the PDCP SDU carries MBS service data; or, receiving a PDCP PDU forwarded by an original base station, wherein the PDCP PDU carries SN and MBS service data; or, receiving an IP data packet and SN forwarded by an original base station, wherein the IP data packet carries MBS service data; or receiving SDAP SDU and SN forwarded by the original base station, wherein the SDAP SDU carries MBS service data; or receiving an IP data packet forwarded by the original base station, wherein the IP data packet carries MBS service data.

In an optional manner, in a case that the receiving unit 1201 receives an IP packet forwarded by an original base station, the apparatus further includes:

a processing unit (not shown in the figure), configured to add a PDCP SN to the forwarded MBS service data, where the added PDCP SN is determined based on PDCP SNs of MBS service data transmitted in a multicast manner.

In an optional manner, the added PDCP SN is determined based on the PDCP SN of the first MBS service data transmitted to the terminal device in a multicast manner and the total number of the forwarded MBS service data.

In an optional manner, when the receiving unit 1201 receives an IP packet forwarded by an original base station, the apparatus further includes:

and the processing unit is used for adding PDCP SN to the forwarded MBS service data, and the added PDCP SN is set from an initial value.

In an optional manner, the time when the sending unit 1202 sends the first indication information to the terminal device is located after a first time and before a second time, where the first time refers to a time when the terminal device finishes receiving MBS service data in a unicast manner, and the second time refers to a time when the terminal device starts receiving MBS service data in a multicast manner.

In an optional manner, the apparatus further comprises:

the processing unit is used for judging whether the MBS service data forwarded by the original base station is transmitted on an air interface of the target base station side;

the sending unit 1202 is further configured to send, to the original base station, second indication information if the MBS service data forwarded by the original base station is not transmitted on the air interface of the target base station side yet, where the second indication information is used to indicate the original base station to stop forwarding the MBS service data continuously.

In an optional manner, the apparatus further comprises:

the processing unit is used for judging whether MBS service data forwarded by the original base station exists in the memory of the target base station;

the sending unit 1202 is further configured to send second indication information to the original base station if the MBS service data forwarded by the original base station exists in the memory of the target base station, where the second indication information is used to indicate the original base station to stop forwarding the MBS service data continuously.

In an optional manner, the receiving unit 1201 is further configured to receive a handover complete message sent by the terminal device.

In an optional manner, the first indication information is further used to indicate that the terminal device submits all PDCP SDUs in a receiving window before resetting to a higher layer, where the receiving window before resetting is used for the terminal device to receive MBS service data of the original base station side, where the MBS service data of the original base station side includes MBS service data sent by the original base station and/or MBS service data sent by the target base station and forwarded by the original base station.

In an optional manner, the first indication information is further used to indicate the terminal device to update a value of at least one variable of the reset receiving window to a default value.

In an optional manner, the first indication information is carried in a MAC CE, or in a PDCCH, or in RRC signaling.

In an optional manner, the MBS service data at the original base station side is sent to the original base station by a core network through a first tunnel, and the MBS service data at the target base station side is sent to the target base station by the core network through a second tunnel.

Those skilled in the art should understand that the related description of the transmission apparatus of the MBS service in the embodiment of the present application may be understood by referring to the related description of the transmission method of the MBS service in the embodiment of the present application.

Fig. 13 is a schematic structural diagram of a transmission apparatus of an MBS service provided in an embodiment of the present application, which is applied to an original base station, and the apparatus includes:

a sending unit 1301, configured to send first auxiliary information to a target base station, where the first auxiliary information is used by the target base station to determine whether the original base station needs to forward MBS service data to the target base station;

a receiving unit 1302, configured to receive third indication information sent by the target base station, where the third indication information is used to indicate the source base station to forward MBS service data to the target base station;

the sending unit 1301 is further configured to forward MBS service data to the target base station, and send a switching command to a terminal device, where the switching command is used to trigger the terminal device to switch from the original base station to the target base station, and receive the MBS service data sent by the target base station in a unicast manner and the MBS service data sent by the target base station in a multicast manner.

In an optional manner, the sending unit 1301 is configured to send a handover request message to a target base station, where the handover request message carries related information of a first MBS service and the first auxiliary information, and the first MBS service refers to an MBS service received by the terminal device at the original base station.

In an optional manner, the first auxiliary information is used to determine a first PDCP SN, where the first PDCP SN is a PDCP SN of a last MBS service data sent by the original base station to the terminal device or a PDCP SN of a MBS service data to be sent next.

In an optional manner, the first PDCP SN and the PDCP SN of the MBS service data stored in the memory of the target base station are used by the target base station to determine whether the original base station is required to forward the MBS service data to the target base station; or,

the first PDCP SN and the PDCP SN of the MBS service data which is sent by the target base station are used for the target base station to determine whether the original base station is needed to forward the MBS service data to the target base station.

In an optional manner, the first PDCP SN and the PDCP SN of the MBS service data being sent by the target base station are used by the target base station to determine a first PDCP SN list of the MBS service data forwarded to the target base station by the original base station.

In an optional manner, the receiving unit 1302 is further configured to receive a handover request acknowledgement message sent by the target base station; and the switching request confirmation message carries a first tunnel identifier under the condition that the original base station is required to forward MBS service data to the target base station, wherein the first tunnel identifier is used for forwarding the MBS service data from the original base station to the target base station.

In an optional manner, the handover request acknowledgement message further carries fourth indication information, where the fourth indication information is used to indicate a first PDCP SN list or a first quantity, where the first quantity and the first PDCP SN are used to determine the first PDCP SN list, and the first PDCP SN list refers to a PDCP SN list of MBS service data forwarded by the original base station to the target base station.

In an optional manner, the handover command carries fifth indication information, where the fifth indication information is used to indicate the terminal device to simultaneously receive MBS service data sent by the target base station in a unicast manner and MBS service data sent by the target base station in a multicast manner.

In an optional manner, the MBS service data sent by the target base station in a unicast manner refers to MBS service data forwarded by the source base station.

In an optional manner, the MBS service data at the original base station side is sent to the original base station by a core network through a first tunnel, and the MBS service data at the target base station side is sent to the target base station by the original base station through a second tunnel.

In an optional manner, the original base station and the target base station have independent first protocol stacks and a shared second protocol stack, where the first protocol stack refers to a protocol stack corresponding to the DU, and the second protocol stack refers to a protocol stack corresponding to the CU; or,

the original base station and the target base station are provided with independent total protocol stacks, wherein the total protocol stacks comprise the first protocol stack and the second protocol stack.

Fig. 14 is a schematic structural diagram of a third transmission apparatus for MBS service provided in an embodiment of the present application, where the third transmission apparatus is applied to a terminal device, and the apparatus includes:

a receiving unit 1401, configured to receive a handover command sent by an original base station, and handover the original base station to a target base station;

a sending unit 1402, configured to send sixth indication information to the target base station, where the sixth indication information is used to indicate a second PDCP SN list, and the second PDCP SN list refers to a missing PDCP SN list between the original base station and the target base station;

the receiving unit 1401 is further configured to receive MBS service data sent by the target base station in a unicast manner and MBS service data sent in a multicast manner.

In an optional manner, the handover command carries seventh indication information, where the seventh indication information is used to indicate whether the terminal device reports the second PDCP SN list to the target base station.

In an optional manner, the sending unit 1402 is configured to send a handover complete message to the target base station, where the handover complete message carries the sixth indication information.

In an optional manner, MBS service data sent by the target base station in a unicast manner is determined based on the second PDCP SN list.

Fig. 15 is a schematic structural diagram of a communication device 1500 provided in an embodiment of the present application. The communication device may be a terminal device or a network device, and the communication device 1500 shown in fig. 15 includes a processor 1510, and the processor 1510 may call and execute a computer program from a memory to implement the method in the embodiment of the present application.

Optionally, as shown in fig. 15, the communication device 1500 may also include a memory 1520. From the memory 1520, the processor 1510 can call and execute a computer program to implement the method in the embodiment of the present application.

The memory 1520 may be a separate device from the processor 1510 or may be integrated into the processor 1510.

Optionally, as shown in fig. 15, the communication device 1500 may further include a transceiver 1530, and the processor 1510 may control the transceiver 1530 to communicate with other devices, and specifically, may transmit information or data to other devices or receive information or data transmitted by other devices.

The transceiver 1530 may include a transmitter and a receiver, among others. The transceiver 1530 may further include one or more antennas.

Optionally, the communication device 1500 may specifically be a network device in this embodiment, and the communication device 1500 may implement a corresponding process implemented by the network device in each method in this embodiment, which is not described herein again for brevity.

Optionally, the communication device 1500 may specifically be a mobile terminal/terminal device according to this embodiment, and the communication device 1500 may implement a corresponding process implemented by the mobile terminal/terminal device in each method according to this embodiment, which is not described herein again for brevity.

Fig. 16 is a schematic structural diagram of a chip of an embodiment of the present application. The chip 1600 shown in fig. 16 includes a processor 1610, and the processor 1610 can call and execute a computer program from a memory to implement the method in the embodiment of the present application.

Optionally, as shown in fig. 16, the chip 1600 may further include a memory 1620. From the memory 1620, the processor 1610 can call and run a computer program to implement the method in the embodiment of the present application.

The memory 1620 may be a separate device from the processor 1610, or may be integrated into the processor 1610.

Optionally, the chip 1600 may also include an input interface 1630. The processor 1610 can control the input interface 1630 to communicate with other devices or chips, and in particular, can obtain information or data transmitted by other devices or chips.

Optionally, the chip 1600 may also include an output interface 1640. The processor 1610 may control the output interface 1640 to communicate with other devices or chips, and in particular may output information or data to other devices or chips.

Optionally, the chip may be applied to the network device in the embodiment of the present application, and the chip may implement the corresponding process implemented by the network device in each method in the embodiment of the present application, and for brevity, details are not described here again.

Optionally, the chip may be applied to the mobile terminal/terminal device in the embodiment of the present application, and the chip may implement the corresponding process implemented by the mobile terminal/terminal device in each method in the embodiment of the present application, and for brevity, no further description is given here.

It should be understood that the chips mentioned in the embodiments of the present application may also be referred to as a system-on-chip, a system-on-chip or a system-on-chip, etc.

Fig. 17 is a schematic block diagram of a communication system 1700 according to an embodiment of the present application. As shown in fig. 17, the communication system 1700 includes a terminal device 1710 and a network device 1720.

The terminal device 1710 may be configured to implement corresponding functions implemented by the terminal device in the foregoing method, and the network device 1720 may be configured to implement corresponding functions implemented by the network device in the foregoing method, which is not described herein again for brevity.

It should be understood that the processor of the embodiments of the present application may be an integrated circuit chip having signal processing capabilities. In implementation, the steps of the above method embodiments may be performed by integrated logic circuits of hardware in a processor or instructions in the form of software. The Processor may be a general purpose Processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), an off-the-shelf Programmable Gate Array (FPGA) or other Programmable logic device, discrete Gate or transistor logic device, or discrete hardware components. The various methods, steps, and logic blocks disclosed in the embodiments of the present application may be implemented or performed. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like. The steps of the method disclosed in connection with the embodiments of the present application may be directly implemented by a hardware decoding processor, or implemented by a combination of hardware and software modules in the decoding processor. The software modules may be located in ram, flash, rom, prom, or eprom, registers, etc. as is well known in the art. The storage medium is located in a memory, and a processor reads information in the memory and completes the steps of the method in combination with hardware of the processor.

It will be appreciated that the memory in the embodiments of the subject application can be either volatile memory or nonvolatile memory, or can include both volatile and nonvolatile memory. The non-volatile Memory may be a Read-Only Memory (ROM), a Programmable ROM (PROM), an Erasable PROM (EPROM), an Electrically Erasable PROM (EEPROM), or a flash Memory. Volatile Memory can be Random Access Memory (RAM), which acts as external cache Memory. By way of example, but not limitation, many forms of RAM are available, such as Static random access memory (Static RAM, SRAM), dynamic Random Access Memory (DRAM), synchronous Dynamic random access memory (Synchronous DRAM, SDRAM), double Data Rate Synchronous Dynamic random access memory (DDR SDRAM), enhanced Synchronous SDRAM (ESDRAM), synchronous link SDRAM (SLDRAM), and Direct Rambus RAM (DR RAM). It should be noted that the memory of the systems and methods described herein is intended to comprise, without being limited to, these and any other suitable types of memory.

It should be understood that the above memories are exemplary but not limiting illustrations, for example, the memories in the embodiments of the present application may also be Static Random Access Memory (SRAM), dynamic random access memory (dynamic RAM, DRAM), synchronous Dynamic Random Access Memory (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (enhanced SDRAM, ESDRAM), synchronous Link DRAM (SLDRAM), direct Rambus RAM (DR RAM), and the like. That is, the memory in the embodiments of the present application is intended to comprise, without being limited to, these and any other suitable types of memory.

The embodiment of the application also provides a computer readable storage medium for storing the computer program.

Optionally, the computer-readable storage medium may be applied to the network device in the embodiment of the present application, and the computer program enables the computer to execute the corresponding process implemented by the network device in each method in the embodiment of the present application, which is not described herein again for brevity.

Optionally, the computer-readable storage medium may be applied to the mobile terminal/terminal device in the embodiment of the present application, and the computer program enables the computer to execute the corresponding process implemented by the mobile terminal/terminal device in each method in the embodiment of the present application, which is not described herein again for brevity.

Embodiments of the present application also provide a computer program product comprising computer program instructions.

Optionally, the computer program product may be applied to the network device in the embodiment of the present application, and the computer program instructions enable the computer to execute corresponding processes implemented by the network device in the methods in the embodiment of the present application, which are not described herein again for brevity.

Optionally, the computer program product may be applied to the mobile terminal/terminal device in the embodiment of the present application, and the computer program instructions enable the computer to execute the corresponding processes implemented by the mobile terminal/terminal device in the methods in the embodiment of the present application, which are not described herein again for brevity.

The embodiment of the application also provides a computer program.

Optionally, the computer program may be applied to the network device in the embodiment of the present application, and when the computer program runs on a computer, the computer is enabled to execute a corresponding process implemented by the network device in each method in the embodiment of the present application, and for brevity, details are not described here again.

Optionally, the computer program may be applied to the mobile terminal/terminal device in the embodiment of the present application, and when the computer program runs on a computer, the computer is enabled to execute the corresponding process implemented by the mobile terminal/terminal device in each method in the embodiment of the present application, which is not described herein again for brevity.

Those of ordinary skill in the art will appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application.

It is clear to those skilled in the art that, for convenience and brevity of description, the specific working processes of the above-described systems, apparatuses and units may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again.

In the several embodiments provided in the present application, it should be understood that the disclosed system, apparatus and method may be implemented in other ways. For example, the above-described apparatus embodiments are merely illustrative, and for example, the division of the units is only one logical division, and other divisions may be realized in practice, for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or units, and may be in an electrical, mechanical or other form.

The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.

In addition, functional units in the embodiments of the present application may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit.

The functions, if implemented in the form of software functional units and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present application or portions thereof that substantially contribute to the prior art may be embodied in the form of a software product stored in a storage medium and including instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present application. And the aforementioned storage medium includes: various media capable of storing program codes, such as a usb disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk, or an optical disk.

The above description is only for the specific embodiments of the present application, but the scope of the present application is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present application, and shall be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

A transmission method of multimedia multicast service (MBS) service comprises the following steps:

the target base station receives the MBS service data forwarded by the original base station, and the target base station sends the MBS service data forwarded by the original base station to the terminal equipment in a unicast mode;

and the target base station sends first indication information to the terminal equipment, wherein the first indication information is used for indicating the terminal equipment to reset a receiving window, and the reset receiving window is used for receiving the MBS service data sent by the target base station by the terminal equipment in a multicast mode.
The method of claim 1, wherein before the target base station receives the MBS service data forwarded by the original base station, the method further comprises:

the target base station receives a switching request message sent by the original base station, wherein the switching request message carries relevant information of a first MBS service, and the first MBS service refers to an MBS service received by the terminal equipment at the original base station;

and the target base station sends a switching request confirmation message to the original base station, wherein the switching request confirmation message carries a first tunnel identifier, and the first tunnel identifier is used for forwarding MBS service data to the target base station by the original base station.
The method of claim 2, wherein the information related to the first MBS service includes at least one of: service identification, session identification, physical channel configuration information and logical channel configuration information.
The method according to any one of claims 1 to 3, wherein the receiving, by the target base station, the MBS service data forwarded by the original base station comprises:

the target base station receives a packet data convergence protocol PDCP service data unit SDU and a sequence number SN forwarded by an original base station, wherein the PDCP SDU carries MBS service data; or,

the target base station receives a PDCP protocol data unit PDU forwarded by an original base station, wherein the PDCP PDU carries SN and MBS service data; or,

the target base station receives an IP data packet and an SN forwarded by an original base station, wherein the IP data packet carries MBS service data; or,

the target base station receives service data adaptation protocols SDAP SDU and SN forwarded by an original base station, wherein the SDAP SDU carries MBS service data; or,

and the target base station receives an IP data packet forwarded by the original base station, wherein the IP data packet carries MBS service data.
The method of claim 4, wherein, in case that the target base station receives the IP data packet forwarded by the original base station, the method further comprises:

and the target base station adds PDCP SN to the forwarded MBS service data, and the added PDCP SN is determined based on the PDCP SN of the MBS service data transmitted in a multicast mode.
The method of claim 5, wherein the adding the PDCP SN based on the PDCP SN of the MBS service data transmitted in the multicast mode comprises:

the added PDCP SN is determined based on the PDCP SN of the first MBS service data transmitted to the terminal equipment in a multicast mode and the total number of the forwarded MBS service data.
The method of claim 4, wherein, in case that the target base station receives the IP data packet forwarded by the original base station, the method further comprises:

and the target base station adds PDCP SN to the forwarded MBS service data, and the added PDCP SN is set from an initial value.
The method of claim 7, wherein a time when the target base station sends the first indication information to the terminal device is located after a first time and before a second time, the first time refers to a time when the terminal device finishes receiving MBS service data in a unicast manner, and the second time refers to a time when the terminal device starts receiving MBS service data in a multicast manner.
The method of any one of claims 1 to 8, wherein after the target base station receives the MBS service data forwarded by the original base station, the method further comprises:

the target base station judges whether the MBS service data forwarded by the original base station is transmitted on an air interface of the target base station side;

and if the MBS service data forwarded by the original base station is not transmitted on the air interface of the target base station side, the target base station sends second indication information to the original base station, wherein the second indication information is used for indicating the original base station to stop forwarding the MBS service data continuously.
The method of any one of claims 1 to 8, wherein after the target base station receives the MBS service data forwarded by the original base station, the method further comprises:

the target base station judges whether MBS service data forwarded by the original base station exists in a memory of the target base station;

if the memory of the target base station has the MBS service data forwarded by the original base station, the target base station sends second indication information to the original base station, and the second indication information is used for indicating the original base station to stop forwarding the MBS service data continuously.
The method according to any one of claims 1 to 10, wherein the target base station sends the MBS service data forwarded by the original base station to the terminal device in a unicast manner, including:

and after receiving the switching completion message sent by the terminal equipment, the target base station sends the MBS service data forwarded by the original base station to the terminal equipment in a unicast mode.
The method according to any one of claims 1 to 11, wherein the first indication information is further used to indicate that the terminal device delivers all PDCP SDUs in a receiving window before resetting to a higher layer, where the receiving window before resetting is used for the terminal device to receive MBS service data on the original base station side, where the MBS service data on the original base station side includes MBS service data sent by the original base station and/or MBS service data sent by the target base station and forwarded from the original base station.
The method according to any one of claims 1 to 12, wherein the first indication information is further used to instruct the terminal device to update a value of at least one variable of the reset receive window to a default value.
The method according to any of claims 1 to 13, wherein the first indication information is carried in a medium access control element, MAC CE, or in a physical downlink control channel, PDCCH, or in radio resource control, RRC, signaling.
The method as claimed in any one of claims 1 to 14, wherein the MBS service data on the original base station side is sent to the original base station by a core network through a first tunnel, and the MBS service data on the target base station side is sent to the target base station by a core network through a second tunnel.
A transmission method of MBS service, the method comprises:

an original base station sends first auxiliary information to a target base station, wherein the first auxiliary information is used for the target base station to determine whether the original base station needs to forward MBS service data to the target base station;

the source base station receives third indication information sent by the target base station, wherein the third indication information is used for indicating the source base station to forward MBS service data to the target base station;

the source base station transmits MBS service data to the target base station and sends a switching command to the terminal equipment, wherein the switching command is used for triggering the terminal equipment to be switched from the original base station to the target base station and receiving the MBS service data sent by the target base station in a unicast mode and the MBS service data sent by the target base station in a multicast mode.
The method of claim 16, wherein the original base station transmitting first assistance information to a target base station comprises:

the original base station sends a switching request message to a target base station, wherein the switching request message carries relevant information of a first MBS service and the first auxiliary information, and the first MBS service refers to the MBS service received by the terminal equipment at the original base station.
The method of claim 17, wherein the information related to the first MBS service includes at least one of: service identification, session identification, physical channel configuration information and logical channel configuration information.
The method according to any of claims 16 to 18, wherein the first assistance information is used to determine a first PDCP SN, which is a PDCP SN of a last MBS service data transmitted by the original base station to the terminal device or a PDCP SN of a MBS service data to be transmitted next.
The method of claim 19, wherein,

the first PDCP SN and the PDCP SN of the MBS service data existing in the memory of the target base station are used for the target base station to determine whether the original base station is needed to forward the MBS service data to the target base station; or,

the first PDCP SN and the PDCP SN of the MBS service data which is sent by the target base station are used for the target base station to determine whether the original base station is needed to forward the MBS service data to the target base station.
The method as claimed in claim 20, wherein the first PDCP SN and the PDCP SN of the MBS service data being transmitted by the target base station are used for the first PDCP SN list for the target base station to determine the MBS service data forwarded by the original base station to the target base station.
The method of claim 21, wherein the method further comprises:

the original base station receives a switching request confirmation message sent by the target base station; and when the original base station is required to forward the MBS service data to the target base station, the switching request confirmation message carries a first tunnel identifier, and the first tunnel identifier is used for the original base station to forward the MBS service data to the target base station.
The method of claim 22, wherein the handover request acknowledgement message further carries fourth indication information, the fourth indication information is used to indicate a first PDCP SN list or a first number, the first number and the first PDCP SN are used to determine the first PDCP SN list, and the first PDCP SN list refers to a PDCP SN list of MBS service data forwarded by the original base station to the target base station.
The method according to any one of claims 16 to 23, wherein the handover command carries fifth indication information, and the fifth indication information is used to indicate the terminal device to simultaneously receive MBS service data sent by the target base station in a unicast manner and MBS service data sent by the target base station in a multicast manner.
The method of any one of claims 16 to 24, wherein the MBS service data transmitted by the target base station in a unicast manner refers to MBS service data forwarded from the source base station.
The method of any one of claims 16 to 25, wherein MBS service data on the original base station side is sent to the original base station by a core network through a first tunnel, and MBS service data on the target base station side is sent to the target base station by the original base station through a second tunnel.
The method of any one of claims 16 to 26,

the original base station and the target base station are provided with independent first protocol stacks and shared second protocol stacks, wherein the first protocol stacks refer to protocol stacks corresponding to the distribution unit DU, and the second protocol stacks refer to protocol stacks corresponding to the concentration unit CU; or,

the original base station and the target base station are provided with independent total protocol stacks, wherein the total protocol stacks comprise the first protocol stack and the second protocol stack.
A transmission method of MBS service, the method comprises:

the terminal equipment receives a switching command sent by an original base station and switches from the source base station to a target base station;

the terminal equipment sends sixth indication information to the target base station, wherein the sixth indication information is used for indicating a second PDCP SN list, and the second PDCP SN list refers to a missing PDCP SN list between the original base station and the target base station;

and the terminal equipment receives MBS service data sent by the target base station in a unicast mode and MBS service data sent in a multicast mode.
The method of claim 28, wherein the handover command carries seventh indication information, and the seventh indication information is used to indicate whether the terminal device reports the second PDCP SN list to the target base station.
The method according to claim 28 or 29, wherein the terminal device sends sixth indication information to the target base station, comprising:

and the terminal equipment sends a switching completion message to the target base station, wherein the switching completion message carries the sixth indication information.
The method of any one of claims 28 to 30, wherein MBS service data transmitted by the target base station in a unicast manner is determined based on the second PDCP SN list.
The method of any one of claims 28 to 31, wherein MBS service data on the original base station side is sent to the original base station by a core network through a first tunnel, and MBS service data on the target base station side is sent to the target base station by the original base station through a second tunnel.
The method of any one of claims 28 to 32,

the original base station and the target base station are provided with independent first protocol stacks and shared second protocol stacks, wherein the first protocol stack refers to a protocol stack corresponding to the DU, and the second protocol stack refers to a protocol stack corresponding to the CU; or,

the original base station and the target base station are provided with independent total protocol stacks, wherein the total protocol stacks comprise the first protocol stack and the second protocol stack.
A transmission device of MBS service is applied to a target base station, the device comprises:

a receiving unit, configured to receive MBS service data forwarded by an original base station;

a sending unit, configured to send, according to a unicast manner, MBS service data forwarded by the original base station to a terminal device; and sending first indication information to the terminal equipment, wherein the first indication information is used for indicating the terminal equipment to reset a receiving window, and the reset receiving window is used for receiving MBS service data sent by the target base station by the terminal equipment in a multicast mode.
The apparatus of claim 34, wherein,

the receiving unit is further configured to receive a handover request message sent by the original base station, where the handover request message carries related information of a first MBS service, and the first MBS service refers to an MBS service received by the terminal device at the original base station;

the sending unit is further configured to send a handover request acknowledgement message to the original base station, where the handover request acknowledgement message carries a first tunnel identifier, and the first tunnel identifier is used for the original base station to forward MBS service data to the target base station.
The apparatus of claim 35, wherein the information related to the first MBS service comprises at least one of: service identification, session identification, physical channel configuration information and logical channel configuration information.
The apparatus according to any one of claims 34 to 36, wherein the receiving unit is configured to receive PDCP SDUs and SNs forwarded by an original base station, where the PDCP SDUs carry MBS service data; or, receiving a PDCP PDU forwarded by an original base station, wherein the PDCP PDU carries SN and MBS service data; or receiving an IP data packet and an SN forwarded by an original base station, wherein the IP data packet carries MBS service data; or receiving SDAP SDU and SN forwarded by the original base station, wherein the SDAP SDU carries MBS service data; or receiving an IP data packet forwarded by the original base station, wherein the IP data packet carries MBS service data.
The apparatus as claimed in claim 37, wherein, in the case that the receiving unit receives the IP packet forwarded by the original base station, the apparatus further comprises:

and the processing unit is used for adding PDCP SN to the forwarded MBS service data, and the added PDCP SN is determined based on the PDCP SN of the MBS service data transmitted in a multicast mode.
The apparatus of claim 38, wherein the added PDCP SN is determined based on a PDCP SN of a first MBS service data multicast to the terminal device and a total number of the forwarded MBS service data.
The apparatus as claimed in claim 37, wherein, in the case that the receiving unit receives the IP packet forwarded by the original base station, the apparatus further comprises:

and the processing unit is used for adding PDCP SN to the forwarded MBS service data, and the added PDCP SN is set from an initial value.
The apparatus of claim 40, wherein a time when the sending unit sends the first indication information to the terminal device is located after a first time when the terminal device finishes receiving MBS service data in unicast mode and before a second time when the terminal device starts receiving MBS service data in multicast mode.
The apparatus of any one of claims 34 to 41, wherein the apparatus further comprises:

a processing unit, configured to determine whether MBS service data forwarded by the original base station has been transmitted over an air interface of the target base station;

the sending unit is further configured to send second indication information to the original base station if the MBS service data forwarded by the original base station is not transmitted on the air interface of the target base station side, where the second indication information is used to indicate the original base station to stop forwarding the MBS service data continuously.
The apparatus of any one of claims 34 to 41, wherein the apparatus further comprises:

the processing unit is used for judging whether MBS service data forwarded by the original base station exists in the memory of the target base station;

the sending unit is further configured to send second indication information to the original base station if the MBS service data forwarded by the original base station exists in the memory of the target base station, where the second indication information is used to indicate the original base station to stop forwarding the MBS service data continuously.
The apparatus according to any one of claims 34 to 43, wherein the receiving unit is further configured to receive a handover complete message sent by the terminal device.
The apparatus according to any one of claims 34 to 44, wherein the first indication information is further configured to instruct the terminal device to deliver all PDCP SDUs in a receiving window before resetting to a higher layer, where the receiving window before resetting is used for the terminal device to receive MBS service data on the original base station side, where the MBS service data on the original base station side includes MBS service data sent by the original base station and/or MBS service data forwarded from the original base station and sent by the target base station.
The apparatus of any one of claims 34 to 45, wherein the first indication information is further configured to instruct the terminal device to update a value of at least one variable of the reset receive window to a default value.
The apparatus of any one of claims 34 to 46, wherein the first indication information is carried in a MAC CE, or in a PDCCH, or in RRC signaling.
The apparatus of any one of claims 34 to 47, wherein the MBS service data on the original base station side is sent to the original base station by a core network through a first tunnel, and the MBS service data on the target base station side is sent to the target base station by a core network through a second tunnel.
A transmission device of MBS service is applied to an original base station, the device comprises:

a sending unit, configured to send first auxiliary information to a target base station, where the first auxiliary information is used by the target base station to determine whether the original base station needs to forward MBS service data to the target base station;

a receiving unit, configured to receive third indication information sent by the target base station, where the third indication information is used to indicate the source base station to forward MBS service data to the target base station;

the sending unit is further configured to forward MBS service data to the target base station, and send a handover command to a terminal device, where the handover command is used to trigger the terminal device to handover from the original base station to the target base station, and receive the MBS service data sent by the target base station in a unicast manner and the MBS service data sent by the target base station in a multicast manner.
The apparatus of claim 49, wherein the sending unit is configured to send a handover request message to a target base station, where the handover request message carries related information of a first MBS service and the first auxiliary information, and the first MBS service refers to an MBS service received by the terminal device at the original base station.
The apparatus of claim 50, wherein the information related to the first MBS service comprises at least one of: service identification, session identification, physical channel configuration information and logical channel configuration information.
The apparatus according to any of claims 49-51, wherein the first assistance information is used to determine a first PDCP SN, which is a PDCP SN of the last MBS service data transmitted by the original base station to the terminal device or a PDCP SN of the next MBS service data to be transmitted.
The apparatus of claim 52, wherein,

the first PDCP SN and the PDCP SN of the MBS service data existing in the memory of the target base station are used for the target base station to determine whether the original base station is needed to forward the MBS service data to the target base station; or,

the first PDCP SN and the PDCP SN of the MBS service data which is sent by the target base station are used for the target base station to determine whether the original base station is needed to forward the MBS service data to the target base station.
The apparatus of claim 53, wherein the first PDCP SN and the PDCP SN of the MBS service data being transmitted by the target base station are used for the first PDCP SN list of the MBS service data determined by the target base station to be forwarded by the original base station to the target base station.
The apparatus of claim 54, wherein the receiving unit is further configured to receive a handover request acknowledge message sent by the target base station; and the switching request confirmation message carries a first tunnel identifier under the condition that the original base station is required to forward MBS service data to the target base station, wherein the first tunnel identifier is used for forwarding the MBS service data from the original base station to the target base station.
The apparatus of claim 55, wherein the handover request acknowledgement message further carries fourth indication information, the fourth indication information is used to indicate a first PDCP SN list or a first quantity, the first quantity and the first PDCP SN are used to determine the first PDCP SN list, and the first PDCP SN list refers to a PDCP SN list of MBS service data forwarded by the original base station to the target base station.
The apparatus of any of claims 49 to 56, wherein the handover command carries fifth indication information, and the fifth indication information is used to indicate the terminal device to simultaneously receive MBS service data sent by the target base station in a unicast manner and MBS service data sent by the target base station in a multicast manner.
The apparatus of any one of claims 49 to 57, wherein the MBS service data transmitted by the target base station in a unicast manner refers to MBS service data forwarded from the source base station.
The apparatus of any one of claims 49 to 58, wherein the MBS service data on the original base station side is sent to the original base station by a core network through a first tunnel, and the MBS service data on the target base station side is sent to the target base station by the original base station through a second tunnel.
The apparatus of any one of claims 49-59,

the original base station and the target base station are provided with independent first protocol stacks and shared second protocol stacks, wherein the first protocol stack refers to a protocol stack corresponding to the DU, and the second protocol stack refers to a protocol stack corresponding to the CU; or,

the original base station and the target base station are provided with independent total protocol stacks, wherein the total protocol stacks comprise the first protocol stack and the second protocol stack.
A transmission device of MBS service is applied to terminal equipment, the device comprises:

a receiving unit, configured to receive a handover command sent by an original base station, and handover the original base station to a target base station;

a sending unit, configured to send sixth indication information to the target base station, where the sixth indication information is used to indicate a second PDCP SN list, and the second PDCP SN list refers to a missing PDCP SN list between the original base station and the target base station;

the receiving unit is further configured to receive MBS service data sent by the target base station in a unicast manner and MBS service data sent in a multicast manner.
The apparatus of claim 61, wherein the handover command carries seventh indication information, and the seventh indication information is used to indicate whether the terminal device reports the second PDCP SN list to the target base station.
The apparatus of claim 61 or 62, wherein the sending unit is configured to send a handover complete message to the target base station, and the handover complete message carries the sixth indication information.
The apparatus of any one of claims 61 to 63, wherein MBS traffic data transmitted by the target base station in a unicast manner is determined based on the second PDCP SN list.
The apparatus of any one of claims 61 to 64, wherein the MBS service data of the original base station side is sent to the original base station by a core network through a first tunnel, and the MBS service data of the target base station side is sent to the target base station by the original base station through a second tunnel.
The apparatus of any one of claims 61-65,

the original base station and the target base station are provided with independent first protocol stacks and shared second protocol stacks, wherein the first protocol stack refers to a protocol stack corresponding to the DU, and the second protocol stack refers to a protocol stack corresponding to the CU; or,

the original base station and the target base station are provided with independent total protocol stacks, wherein the total protocol stacks comprise the first protocol stack and the second protocol stack.
A communication device, comprising: a processor and a memory for storing a computer program, the processor being configured to invoke and execute the computer program stored in the memory, to perform the method of any of claims 1 to 15, or the method of any of claims 16 to 27, or the method of any of claims 28 to 33.
A chip, comprising: a processor for calling and running a computer program from a memory so that a device on which the chip is installed performs the method of any of claims 1 to 15, or the method of any of claims 16 to 27, or the method of any of claims 28 to 33.
A computer readable storage medium storing a computer program for causing a computer to perform the method of any of claims 1 to 15, or the method of any of claims 16 to 27, or the method of any of claims 28 to 33.
A computer program product comprising computer program instructions to cause a computer to perform the method of any of claims 1 to 15, or the method of any of claims 16 to 27, or the method of any of claims 28 to 33.
A computer program for causing a computer to perform the method of any one of claims 1 to 15, or the method of any one of claims 16 to 27, or the method of any one of claims 28 to 33.