METHOD FOR CHANGING MODE, TERMINAL AND DEVICE ON THE NETWORK SIDE.

Abstract

This application describes a mode-switching method, a terminal, and a network-side device; the method can be applied to a network-side target device and includes: reserving a multicast air interface resource in case multicast QoS quality of service information is received from a multicast MB NF transmit network function, where the multicast air interface resource is used for a terminal to receive multicast service data in a switched target mode, and the multicast QoS information corresponds to the multicast service data; and forwarding the multicast air interface resource to a source network-side device or to the MB NF.

Description

METHOD FOR CHANGING MODE, TERMINAL AND DEVICE ON THE NETWORK SIDE CROSS REFERENCE TO RELATED APPLICATIONS This application claims priority from Chinese Patent Application No. 202010519756.2, filed in China on June 9, 2020, which is incorporated herein by reference in its entirety. TECHNICAL FIELD This application falls within the field of communication technologies and relates specifically to a mode-switching method, a terminal, and a network-side device. BACKGROUND OF THE INVENTION A terminal can establish a Protocol Data Unit (PDU) session to a Data Network (DN) element through a User Plane Function (UPF) network element, and the PDU session provides PDU connectivity service between the terminal and the DN network element. For a terminal using a point-to-point PDU session mode to receive multicast traffic and switch to a target network-side device that supports point-to-multipoint multicast, the terminal must first use a PDU session switch procedure to transfer the PDU session to the target network-side device. If the terminal wants to use the most efficient multicast data transmission mode, either the terminal or the target network-side device must initiate a mode switch to change to point-to-multipoint multicast transmission mode. It can be learned from the description above that the terminal first needs to switch the PDU session to the target network-side device using the PDU session switch procedure, and then the terminal or target network-side device initiates the mode switch to change to point-to-multipoint multicast transmission mode. This mode switch exhibits relatively low switching efficiency. RAQC ίΠ / ΖΖηΖ / Ε / ΥΙΛΙ BRIEF DESCRIPTION OF THE INVENTION The purpose of the modalities in this application is to provide a mode-switching method, a terminal, and a network-side device to solve a low-efficiency mode-switching problem. To resolve the above technical problem, this request is implemented as follows: According to a first aspect, a mode-switching method is provided, applied to a target device on the network side, and the method includes: reserving a multicast air interface resource in the case of receiving multicast QoS quality of service information from an MB NF multicast broadcast network function, where the multicast air interface resource is used for a terminal to receive multicast service data in a switched target mode, and the multicast QoS information corresponds to the multicast service data; and sending the multicast air interface resource to a source network-side device or to the MB NF. According to a second aspect, a mode-switching method is provided, applied to an MB NF, and the method includes: sending multicast QoS information to a target network-side device, where the multicast QoS information is used for the target network-side device to reserve a multicast air interface resource, the multicast air interface resource is used for a terminal to receive multicast service data in a switched target mode, and the multicast QoS information corresponds to the multicast service data. According to a third aspect, a mode-switching method is provided, applied to a device on the source network side, and the method includes: receiving a multicast air interface resource, where the multicast air interface resource is reserved by a device on the target network side in the case of receiving multicast QoS information from an MB NF, the multicast air interface resource is used for a terminal to receive multicast service data in a switched target mode, and the multicast QoS information corresponds to the multicast service data. According to a fourth aspect, a mode-switching method is provided, applied to a terminal, and the method includes: receiving a multicast air interface resource, where the multicast air interface resource is reserved by a device on the target network side in case multicast QoS information is received from an MB NF, the multicast air interface resource is used for the terminal to receive multicast service data in a switched target mode, and the multicast QoS information corresponds to the data of RAQC ίΠ / ΖΖηΖ / Ε / ΥΙΛΙ multicast service. According to a fifth aspect, a mode-changing apparatus is provided, and the apparatus includes: a resource reservation module, configured to reserve a multicast air interface resource in the event that multicast QoS quality of service information is received from an MB NF multicast broadcast network function, where the multicast air interface resource is used for a terminal to receive multicast service data in a changed target mode, and the multicast QoS information corresponds to the multicast service data; and a sending module, configured to send the multicast air interface resource to a device on the source network side or to the MB NF. According to a sixth aspect, a mode-changing apparatus is provided, and the apparatus includes: a sending module, configured to send multicast QoS information to a target network-side device, where the multicast QoS information is used for the target network-side device to reserve a multicast air interface resource, the multicast air interface resource is used for a terminal to receive multicast service data in a changed target mode, and the multicast QoS information corresponds to the multicast service data. According to a seventh aspect, a mode-changing apparatus is provided, and the apparatus includes: a receiver module, configured to receive a multicast air interface resource, where the multicast air interface resource is reserved by a device on the target network side in a case where multicast QoS information is received from an MB NF, the multicast air interface resource is used for a terminal to receive multicast service data in a changed target mode, and the multicast QoS information corresponds to the multicast service data. According to an eighth aspect, a mode-changing apparatus is provided, and the apparatus includes: a receiver module, configured to receive a multicast air interface resource, where the multicast air interface resource is reserved by a device on the target network side in a case where multicast QoS information is received from an MB NF, the multicast air interface resource is used for the apparatus to receive multicast service data in a changed target mode, and the multicast QoS information corresponds to the multicast service data. According to a ninth aspect, a terminal is provided when the terminal includes a processor, a memory, and a program or instructions stored in memory and capable of being executed by the processor, and when the program or instructions are executed by the processor, the method is implemented according to the fourth aspect. According to a tenth aspect, a network-side device is provided, RAQC ίΠ / ZZΖηZ / E / YΙΛΙ where the network-side device includes a processor, a memory, and a program or instructions stored in memory and capable of being executed by the processor, and when the program or instructions are executed by the processor, the method is implemented according to the first aspect, the second aspect, or the third aspect. According to an eleventh aspect, a readable storage medium is provided, where the readable storage medium stores a program or instructions. When the program or instructions are executed by a processor, the method is implemented according to the first aspect, the second aspect, the third aspect, or the fourth aspect. According to a twelfth aspect, a chip is provided, where the chip includes a processor and a communications interface, the communications interface is coupled to the processor and the processor is configured to execute a program or instructions to implement the method according to the first aspect, the second aspect, the third aspect, or the fourth aspect. In the modes of this request, in the case of receiving multicast QoS information from the MB NF, the target network-side device reserves the multicast air interface resource and sends the multicast air interface resource to the source network-side device or the MB NF, so that the terminal can switch from a PDU session mode to the target mode and receive multicast service data using the multicast air interface resource, thereby improving the efficiency of the mode change. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a block diagram of a wireless communications system according to one modality of this application; Figure 2 is a schematic flowchart of a mode-changing method according to a modality of this request; Figure 3 is a schematic flowchart of a mode-changing method according to a modality of this request; Figure 4 is a schematic flowchart of a mode-changing method according to a modality of this request; Figure 5 is a schematic flowchart of a mode-changing method according to a modality of this request; Figure 6 is a schematic flowchart of a mode-changing method according to a modality of this request; Figure 7 is a schematic flowchart of a mode-changing method RAQC ίΠ / ZZΖηZ / E / YΙΛΙ in accordance with a modality of this application; Figure 8 is a schematic structural diagram of a mode-changing apparatus according to one modality of this application; Figure 9 is a schematic structural diagram of a mode-changing apparatus according to one modality of this application; Figure 10 is a schematic structural diagram of a mode-changing apparatus according to one modality of this application; Figure 11 is a schematic structural diagram of a mode-changing apparatus according to one modality of this application; Figure 12 is a schematic structural diagram of a communications device pursuant to a modality of this application; Figure 13 is a schematic structural diagram of a terminal according to one modality of this request; and Figure 14 is a schematic structural diagram of a network-side device according to one modality of this request. DETAILED DESCRIPTION OF THE INVENTION The following clearly and completely describes the technical solutions in the forms covered by this application, with reference to the accompanying drawings. It appears that the forms described are only some, rather than all, of the forms covered by this application. All other forms obtained by a person skilled in the art, based on the forms covered by this application without creative effort, will fall within the scope of protection of this application. In the specification and claims of this application, terms such as "first" and "second" are intended to distinguish between similar objects, but do not necessarily indicate a specific order or sequence. It should be understood that the data used in this manner are interchangeable under appropriate circumstances so that the modalities of this application may be implemented in orders other than the order illustrated or described herein, and "first" and "second" are generally used to distinguish objects of the same type without limiting the number of objects; for example, a first object may be one or several. Furthermore, "and / or" in this specification and claims indicates at least one of the connected objects, and the symbol 7 generally indicates that the associated objects are in a relationship of "or." It should be noted that the techniques described in the modalities of this application are not limited to a Long Term Evolution (LTE) or Advanced LTE system (LTE) RAQC in / 77P7 / E / YILI Advanced, LTE-A), and can also be applied to various wireless communication systems, for example, Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Orthogonal Frequency Division Multiple Access (OFDMA), Single-Carrier Frequency-Division Multiple Access (SC-FDMA), and other systems. The terms system and network in the modalities of this application are normally used interchangeably. The techniques described herein can be used in the aforementioned radio systems and technologies, and can also be used in other radio systems and technologies.However, in the following descriptions, a New Radio (NR) system is described for illustrative purposes, and the terms NR are used in most of the following descriptions, although these technologies may also apply to other applications besides the NR system application, e.g., the sixth generation (6thGeneration, 6G) communications system. Figure 1 is a block diagram of a wireless communications system to which the modalities of this application apply. The wireless communications system includes a terminal 11 and a network-side device 12. Terminal 11 may also be referred to as a terminal device or user terminal (User Equipment, UE), and Terminal 11 may be a terminal-side device such as a mobile phone, tablet, laptop, personal digital assistant (PDA), handheld computer, netbook, ultra-mobile personal computer (UMPC), mobile internet device (MID), wearable device, vehicle-on-vehicle (VUE), or pedestrian terminal (PUE). The wearable device includes a wristband, headphones, glasses, or similar items.It should be noted that a specific type of terminal 11 is not limited in the modalities of this application. The network-side device 12 may be a base station or a core network. The base station may be called a NodeB, evolved NodeB, access point, base transceiver station (BTS), radio base station, radio transceiver, basic service set (BSS), extended service set (ESS), home NodeB, home evolved NodeB, WLAN access point, Wi-Fi node, transmitting-receiving point (TRP), or another term appropriate in the art. As long as the same technical effect is achieved, the base station is not limited to a specific technical term.It should be noted that in the modalities of this application, the base station in the NR system is used simply as an example, and no specific type of base station is limited. The following describes in detail a mode-switching method, a terminal, and RAQC ίΠ / ZZΖηZ / E / YΙΛΙ a network-side device provided in the modalities of this application by using specific modalities and application scenarios thereof with reference to the attached drawings. As shown in Figure 2, one version of this application provides a 200 mode change method, and the method can be executed by a device on the target network side. In other words, the method can be executed using software or hardware installed on the target network-side device, and the 200 method includes the following steps. S202: Reserve a multicast air interface resource in case multicast Quality of Service (QoS) information is received from a Multicast Broadcast Network Function (MB NF). The multicast air interface resource is used for a terminal to receive multicast service data in a switched target mode. Multicast QoS information corresponds to the multicast service data. In other words, multicast QoS information is QoS information derived from the multicast service data. Prior to S202, the MB NF could send multicast QoS information to the target device on the network side. Multicast QoS information generally differs from the QoS information of a PDU session. For example, the multicast QoS information sent by the MB NF to the target device on the network side could also carry indication information, which was used to indicate that the multicast QoS information applied to a multicast service. It should be noted that the MB NF mentioned in the modalities of this specification is generally a core network function capable of providing multicast service data; therefore, MB NF may be replaced with other technical terms, e.g., a core network device or a multicast transmission server. In this mode, within a cell provided by a device on the source network side, the terminal can receive a multicast service in a point-to-point PDU session mode. The PDU session mode is based on individual channels, and generally, each terminal corresponds to one channel, resulting in relatively low transmission efficiency for the multicast service data. After switching to a cell provided by the device on the target network side, the terminal can switch to target mode, which may be a point-to-multipoint multicast service transmission mode.For example, when the target network-side device sends a piece of multicast service data, multiple terminals can receive the multicast service data, which can improve the transmission efficiency of the multicast service data compared to PDU session mode. Based on the above description, the mode change mentioned in the... RAQC ίη / 77Ω7 / Β / YΙΛΙ modalities of this request may mean that the terminal switches from the PDU session mode of the device on the source network side to the target mode of the device on the target network side, and the target mode is the transmission mode of the point-to-multipoint multicast service. In this mode, for example, prior to S202, the device on the source network side of the terminal could send a handover request message to the device on the target network side. This handover request message could carry identification information for a Protocol Data Unit (PDU) session, such as a PDU session ID. After receiving the handover request message, the device on the target network side could then send a session update message to the MB NF. This session update message would also carry the PDU session identification information, such as the PDU session ID, enabling the MB NF to send multicast QoS information to the device on the target network side. In this mode, in another example, prior to S202, the device on the source network side of the terminal could send a handover notification message to the MB NF, and the handover notification message could carry the PDU session identification information, for example, the PDU session ID. In this way, the MB NF could send multicast QoS information to the target device on the network side after receiving the handover notification message. S204: Send the multicast air interface resource to the source network side device or MB NF. In this mode, if the target network-side device sends the multicast air interface resource to the source network-side device, the source network-side device can further forward the multicast air interface resource to the terminal. Similarly, if the target network-side device sends the multicast air interface resource to the MB NF, the MB NF can further forward the multicast air interface resource to the terminal via the source network-side device. This allows the terminal to transfer to the target network-side device using the multicast air interface resource and receive multicast service data in a switched target mode. In one example, the device on the target network side can send a handover command to the device on the source network side, where the handover command carries the multicast air interface resource; and the device on the source network side can also send a handover command to the terminal, also carrying the multicast air interface resource. In this way, the terminal can then access the device on the target network side using the multicast air interface resource and send the device a handover completion message, such as a Handover Acknowledgement message. RAQC ίΠ / ΖΖηΖ / Ε / ΥΙΛΙ In another example, the target network-side device can send the multicast air interface resource to the MB NF, and the MB NF sends a handover command (for example, a Handover Command message) to the source network-side device, where the handover command carries the multicast air interface resource. The source network-side device can also send a handover command to the terminal, which carries the multicast air interface resource. In this way, the terminal can then access the target network-side device based on the multicast air interface resource and send the target network-side device a handover completion message, for example, a Handover Acknowledgement message. According to the mode-switching method provided in this application, upon receiving multicast QoS information from the MB NF, the target network-side device reserves the multicast air interface resource and sends the multicast air interface resource to the source network-side device or the MB NF, so that the terminal can switch from a PDU session mode to the target mode and receive multicast service data using the multicast air interface resource, thereby improving the efficiency of the mode-switching process. Regarding the improved efficiency of mode switching, in a related technique, the terminal first needs to perform the PDU session switch and then switch the PDU session to the target mode. The air interface resource required for the PDU session switch differs from the air interface resource required for the target mode. Therefore, the device on the target network side not only needs to reserve the air interface resource required for the PDU session but also the air interface resource required for the target mode. Furthermore, it needs to exchange signaling with the device on the source network side, the terminal, and similar entities to notify the air interface resources, resulting in relatively low switching efficiency.In this mode of this request, there is no need to reserve the air interface resource required for the PDU session change, and a signaling exchange procedure required to notify air interface resources is omitted, thus improving the efficiency of the mode change. Optionally, prior to S202 of mode 200, the method also includes: receiving the PDU session identification information from the source network-side device; and sending the PDU session identification information to the MB NF. The PDU session mentioned in this example can also be called the PDU session to be switched because the terminal is about to switch from PDU session mode to target mode. After receiving the PDU session identification information, the MB NF can know that the terminal needs to perform a mode switch; that is, multicast QoS information can be sent to the target device. RAQC ίη / ΖΖΩΖ / Ε / ΥΙΛΙ network side. In this mode, after sending the PDU session identification information to the MB NF, the target network-side device can also receive at least one of the following from the MB NF: a QoS parameter corresponding to the PDU session, and multicast information. Multicast information, for example, includes at least a Temporary Mobile Group Identifier (TMGI) and an MB NF identifier. Optionally, prior to S202 of mode 200, the method also includes: receiving, from the source network-side device, at least one of the following: a mode change indication and the target mode. In one example, the mode change indication includes a specific QoS flow identifier. In this mode, the source network-side device can send at least a mode change indication and the target mode to the target network-side device to indicate that the terminal needs to perform a mode change. This allows the target network-side device to send a session update message to the MB NF. After receiving the session update message, the MB NF can determine that the terminal needs to perform a mode change; that is, multicast QoS information can be sent to the target network-side device. Optionally, prior to S202 of mode 200, the method also includes: receiving, from the MB NF, at least one of the following: a mode change indication, the target mode, a QoS parameter corresponding to the PDU session, and multicast information. In the various examples above, if the target network device receives the QoS parameter corresponding to the PDU session, it can also reserve an air interface resource for that PDU session. This allows the terminal to receive multicast service data not only in target mode but also in PDU session mode. This approach is applicable to scenarios where the terminal needs to receive multiple types of multicast service data, fulfilling the transmission requirements for these diverse services and improving transmission efficiency. Optionally, mode 200 also includes the following step: sending to the MB NF at least one of the following: an air interface resource for a PDU session and a multicast downlink tunnel resource to receive multicast service data. In this mode, if the air interface resource for the PDU session is sent to the MB NF, the MB NF can also send the air interface resource for the PDU session to the terminal via the source network-side device, so that the terminal subsequently receives the multicast service data from the target network-side device. RAQC ίΠ / ΖΖηΖ / Ε / ΥΙΛΙ in PDU session mode. In this mode, if the multicast downlink tunnel resource is sent to the MB NF, the target network-side device can also receive multicast service data using the multicast downlink tunnel resource and send the multicast service data to the terminal using the multicast air interface resource, so that the terminal can receive multicast service data in target mode using the multicast air interface resource. The mode-switching method provided by the modalities of this application is described in detail below with reference to two specific modalities in Figure 3 and Figure 4. In the modality shown in Figure 3 and Figure 4, the source network-side device, which is a source gNB, and the target network-side device, which is a target gNB, are used as examples for the description. Mode 1 As shown in Figure 3, option 1 includes the following steps: S302: The source gNB sends a handover request message, for example, a Handover Request message, to the target gNB, where the handover request message carries identification information of a PDU session, for example, a PDU session ID. Optionally, the handover request message can also carry a mode change indication, which can be used to indicate that a terminal needs to perform a mode change; and the handover request message can also indicate a target mode. Optionally, the source gNB can use a specific QoS flow identifier to identify that the terminal needs to perform a mode change. S304: The target gNB sends a session update message to an MB NF in accordance with the mode change indication. For example, when the MB NF is a Session Management Function (SMF), the target gNB sends the session update message to the SMF through an Access and Mobility Management Function (AMF); or when the MB NF is an AMF, the target gNB sends the session update message directly to the AMF. The session update message can carry identifying information for a PDU session to be changed, such as a PDU session ID. S306: The MB NF sends a session update response message to the target gNB. In this mode, based on the PDU session ID, the MB NF compares information such as a TMGI, a corresponding QoS parameter, or a packet filtering rule. RAQC ίη / ZZΖΠZ / E / YΙΛΙ from a multicast server that a user receives through the PDU session; and based on the QoS information corresponding to the PDU session and the packet filtering rule, adjusts the QoS information of the PDU session, for example, drops a flow. The session update response message carries multicast QoS information obtained through the adjustment, for example, a QoS parameter corresponding to the multicast service, and may also carry a QoS parameter (which may have been adjusted) corresponding to the PDU session; or the session update response message may also carry multicast information, for example, a TMGI and / or an MB NF identifier. S308: The target gNB reserves a multicast air interface resource based on multicast QoS information. Optionally, the target gNB can also reserve an air interface resource for the PDU session based on the PDU session's QoS parameter. S310: The target gNB returns a handover command, for example, a handover reply message, to the source gNB, carrying an air interface resource. The air interface resource includes the multicast air interface resource and may also include the air interface resource for the PDU session. S312: The originating gNB forwards the air interface resource to the UE terminal using a handover command. S314: The UE accesses the target gNB based on the multicast air interface resource and sends, to the target gNB, a handover completion message, for example, a handover acknowledgment message. S316: The target gNB sends a session update message to the MB NF, which can carry the received multicast information and can also carry multicast downlink tunnel resource information. S318: The MB NF returns a session update response message to the target gNB. In this case, the MB NF (for example, a UPF) can send multicast service data to the target gNB using the multicast downlink tunnel resource, and the target gNB can send multicast service data to the UE using the multicast air interface resource. Mode 2 As shown in Figure 4, this modality includes the following steps: S402: A source gNB sends a handover notification message to an MB NF. For example, when the MB NF is an SMF, the source gNB sends the handover notification message. RAQC ίΠ / ZZΖηZ / E / YΙΛΙ to the SMF through an AMF; or when the MB NF is an AMF, the originating gNB directly sends the handover notification message to the AMF, where the handover notification message (for example, a Handover Required Message) may carry identification information of a PDU session to be changed, for example, a PDU session ID. S404: The MB NF sends a transfer request message to a target gNB, for example, a Transfer Request message. Based on the PDU session ID, the MB NF compares information such as a TMGI, a corresponding QoS parameter, or a packet filtering rule from a multicast service that a user receives through the PDU session; and based on the QoS information corresponding to the PDU session and the packet filtering rule, it adjusts the QoS information of the PDU session, for example, by removing a flow. The handover request message may carry a mode change indication, which can indicate a mode change or a target mode. Specifically, a mode change indication can also be indicated using a multicast QoS parameter. The handover request message also carries QoS information obtained through configuration, such as multicast QoS information for the multicast service, and may also carry a QoS parameter (which may have been configured) for the PDU session. The handover request message may also carry multicast information, such as a TMGI and / or an MB NF identifier. S406: The target gNB reserves a multicast air interface resource and may also reserve an air interface resource for the PDU session based on the PDU session QoS parameter. In this step, the target gNB can reserve the multicast air interface resource based on the mode change indication and multicast QoS information, or it can reserve the multicast air interface resource based only on the multicast QoS information. S408: The target gNB returns to the MB NF a handover response message, for example, a Handover Response message, which carries an air interface resource (which includes the multicast air interface resource, or may also include the air interface resource for the PDU session if a flow is present in the PDU session) to be sent to the source gNB; and the target gNB may further reserve a multicast downlink tunnel resource for multicast service data that is used to send the multicast service data to the target gNB by the MB NF. S410: The MB NF sends a handover command, for example, a Handover Command message, to the originating gNB, which carries an air interface resource. The interface resource RAQC ίη / 77Π7 / E / YΙΛΙ aerial includes the multicast aerial interface resource and may also include the aerial interface resource for the PDU session. S412: The originating gNB forwards the air interface resource to a UE terminal. S414: The UE accesses the target gNB based on the multicast air interface resource and sends, to the target gNB, a handover completion message, for example, a handover acknowledgment message. S416: The target gNB sends, to the MB NF, a session update message which may carry the received multicast information, where the multicast downlink tunnel resource information is sent in this S416 step if it has not already been sent in step S408. S418: The MB NF returns a session update response message to the target gNB. In this case, the MB NF (for example, a UPF) can send multicast service data to the target gNB using the multicast downlink tunnel resource, and the target gNB can send multicast service data to the UE using the multicast air interface resource. The above describes in detail the mode-switching method in this application mode with reference to Figures 2 through 4. The mode-switching method in several other application modes is described in detail below with reference to Figures 5 through 7. It can be understood that the descriptions on the MB NF side, the device side of the source network, and the terminal side are the same as the method description shown in Figures 2 through 4 on the device side of the target network. To avoid repetition, related descriptions are appropriately omitted. Figure 5 is a schematic implementation flowchart of a mode-switching method according to this application modality, and the method is applicable to the MB NF side. As shown in Figure 5, the 500 method includes the following steps: S502: Send multicast QoS information to a target network-side device, where the multicast QoS information is used for the target network-side device to reserve a multicast air interface resource. The multicast air interface resource is used for a terminal to receive multicast service data in a switched target mode, and the multicast QoS information corresponds to the multicast service data. In this mode of this request, if the multicast QoS information is received from the MB NF, the target network-side device reserves the multicast air interface resource and sends the multicast air interface resource to a device on the other side. RAQC ίΠ / ZZΖηZ / E / YΙΛΙ the source network or to the MB NF, so that the terminal can switch from a PDU session mode to the target mode and receive multicast service data using the multicast air interface resource, thereby improving the efficiency of the mode change. Optionally, in one mode, the method also includes: receiving the multicast air interface resource. Optionally, in one mode, the method also includes: receiving PDU session identification information from the target network-side device, where the PDU session identification information is sent by the source network-side device to the target network-side device. Optionally, in one mode, the method also includes: sending to the target device on the network side at least one of the following: a QoS parameter corresponding to the PDU session; and multicast information. Optionally, in one mode, the method also includes: sending at least one of the following to the target device on the network side: an indication of a mode change; the objective mode; a QoS parameter corresponding to the PDU session; and multicast information. Optionally, in one mode, the method also includes: receiving, from the target network-side device, at least one of the following: an air interface resource for a PDU session and a multicast downlink tunnel resource for sending the multicast service data. Optionally, in one mode, the method also includes: sending multicast service data using the multicast downlink tunnel resource. Figure 6 is a schematic implementation flowchart of a mode-switching method according to this application, and the method is applicable to the device side of the source network. As shown in Figure 6, Method 600 includes the following steps: S602: Receive a multicast air interface resource, wherein the multicast air interface resource is reserved by a device on the target network side in the event that multicast QoS information is received from an MB NF. The multicast air interface resource is used for a terminal to receive multicast service data in a switched target mode, and the multicast QoS information corresponds to the multicast service data. In this mode of this request, a device on the originating network side receives RAQC ίΠ / ZZΖηZ / E / YΙΛΙ the multicast air interface resource, where the multicast air interface resource is reserved by the target network side device in the case that multicast QoS information is received from the MB NF, and the source network side device can further send the multicast air interface resource to the terminal, so that the terminal can switch from a PDU session mode to the target mode and receive multicast service data using the multicast air interface resource, thereby improving mode change efficiency. Optionally, in one mode, the method also includes sending PDU session identification information to the target device on the network side. Figure 7 is a schematic implementation flowchart of a mode-switching method according to this mode of this application, and the method is applicable on the terminal side. As shown in Figure 7, Method 700 includes the following steps: S702: Receive a multicast air interface resource, wherein the multicast air interface resource is reserved by a device on the target network side in the event that multicast QoS information is received from an MB NF. The multicast air interface resource is used for the terminal to receive multicast service data in a switched target mode, and the multicast QoS information corresponds to the multicast service data. In this mode of this request, the terminal receives the multicast air interface resource, where the multicast air interface resource is reserved by the device on the target network side in case the multicast QoS information is received from the MB NF, so that the terminal can switch from a PDU session mode to the target mode and receive the multicast service data using the multicast air interface resource, thus improving the efficiency of the mode change. It should be noted that, for the mode-switching method provided by the modalities of this application, the execution body can be a mode-switching device or a control module for executing the mode-switching method on the mode-switching device. In the modalities of this application, the mode-switching device provided is described using the mode-switching method being executed by the mode-switching device as an example. Figure 8 is a schematic structural diagram of a mode-changing device according to one modality of this application. The device corresponds to the target network-side device described in the preceding modalities. As shown in Figure 8, the 800 device includes: an 802 resource reservation module, configured to reserve a multicast air interface resource in the event that multicast QoS information is received from RAQC ίη / 77Π7 / E / YΙΛΙ an MB NF, wherein the multicast air interface resource is used for a terminal to receive multicast service data in a changed target mode, and the multicast QoS information corresponds to the multicast service data; and an 804 send module, configured to send the multicast air interface resource to a device on the source network side or to the MB NF. In this mode of this request, if the multicast QoS information is received from the MB NF, the target network-side device reserves the multicast air interface resource and sends the multicast air interface resource to the source network-side device or the MB NF, so that the terminal can switch from a PDU session mode to the target mode and receive data from the multicast server using the multicast air interface resource, thus improving the efficiency of the mode change. Optionally, in one mode, the 800 appliance also includes a receive module, configured to receive identification information from a protocol data unit PDU session from the source network-side device; and the 804 send module can be configured to send the PDU session identification information to the MB NF. Optionally, in one configuration, the 800 device also includes a receiving module, configured to receive, from the device on the source network side, at least one of the following: an indication of mode change; and the target mode. Optionally, in one mode, the mode change indication includes a specific QoS flow identifier. Optionally, in one configuration, the 800 device also includes a receiving module, configured to receive, from the MB NF, at least one of the following: a QoS parameter corresponding to the PDU session; and multicast information. Optionally, in one configuration, the 800 device also includes a receiving module, configured to receive, from the MB NF, at least one of the following: an indication of a mode change; the objective mode; a QoS parameter corresponding to the PDU session; and multicast information. Optionally, in one mode, if the QoS parameter corresponding to the PDU session is received, the 802 resource reservation module can be configured to reserve an air interface resource for the PDU session. RAQC ίΠ / ΖΖηΖ / Ε / ΥΙΛΙ a mode change indication; the objective mode; a QoS parameter corresponding to the PDU session; and multicast information. Optionally, in one mode, the 900 device also includes a receiving module, configured to receive, from the target device on the network side, at least one of the following: an air interface resource for a PDU session and a multicast downlink tunnel resource for sending multicast service data. Optionally, in one mode, the 902 sending module can be configured to send multicast service data using the multicast downlink tunnel resource. Figure 10 is a schematic structural diagram of a mode-changing device according to one modality of this application. The device corresponds to the source-side network device described in the preceding modalities. As shown in Figure 10, device 1000 includes: A 1002 receiving module, configured to receive a multicast air interface resource, wherein the multicast air interface resource is reserved by a device on the target network side in the event that multicast QoS information is received from an MB NF, the multicast air interface resource is used for a terminal to receive multicast service data in a switched target mode, and the multicast QoS information corresponds to the multicast service data. In this mode of this request, the mode-switching device receives the multicast air interface resource, where the multicast air interface resource is reserved by the target network-side device in case multicast QoS information is received from the MB NF, and the mode-switching device can further send the multicast air interface resource to the terminal, so that the terminal can switch from a PDU session mode to the target mode and receive multicast service data using the multicast air interface resource, thereby improving the efficiency of the mode-switching process. Optionally, in one mode, the 1000 appliance includes a sending module, configured to send PDU session identification information to the target device on the network side. Figure 11 is a schematic structural diagram of a mode-changing device according to one modality of this application. The device corresponds to the terminal described in the preceding modalities. As shown in Figure 11, device 1100 includes: a 1102 receiving module, configured to receive an air interface resource RAQC ίΠ / ZZΖηZ / E / YΙΛΙ of multicast, where the multicast air interface resource is reserved by a device on the target network side in case multicast QoS information is received from an MB NF, the multicast air interface resource is used for the device to receive multicast service data in a changed target mode, and the multicast QoS information corresponds to the multicast service data. In this mode of this request, the mode-switching device receives the multicast air interface resource, where the multicast air interface resource is reserved by the target network-side device in case multicast QoS information is received from the MB NF, so that the mode-switching device, for example, the terminal, can switch from a PDU session mode to the target mode and receive the multicast service data using the multicast air interface resource, thus improving the efficiency of the mode-switching process. The mode-switching device in this modality of this application may be a device, or it may be a component, an integrated circuit, or a chip in a terminal. The device may be a mobile terminal or a non-mobile terminal. For example, a mobile terminal may include, but is not limited to, the terminal types listed above, and a non-mobile terminal may be a server, network-attached storage (NAS), a personal computer (PC), a television (TV), an ATM, a self-service machine, or similar, which is not specifically limited in this modality of this application. The mode-switching device in this modality of this application may be a device with an operating system. The operating system may be an Android operating system, an iOS operating system, or other possible operating systems, and is not specifically limited in the modalities of this application. The mode-changing device provided in this application is capable of implementing the processes implemented in the method's modalities shown in Figures 2 through 7, with the same technical effects achieved. To avoid repetition, the details are not described again here. Optionally, as shown in Figure 12, one embodiment of this application further provides a communications device 1200, which includes a processor 1201, a memory 1202, and a program or instructions stored in memory 1202 and capable of execution by the processor 1201. For example, when the communications device 1200 is a terminal and the program or instructions are executed by the processor 1201, the procedures of the previous embodiment of the mode-switching method are implemented, achieving the same technical effects. When the communications device 1200 is a network-side device and the program or instructions are executed by the processor RAQC ίΠ / ΖΖηΖ / Ε / ΥΙΛΙ 1201, the procedures of the previous mode-switching method are implemented, achieving the same technical effects. To avoid repetition, the details are not described again here. Figure 13 is a schematic diagram of a terminal hardware structure for implementing the modalities of this application. The 1300 terminal includes, among other components, such as a radio frequency unit 1301, a network module 1302, an audio output unit 1303, an input unit 1304, a sensor 1305, a display unit 1306, a user input unit 1307, an interface unit 1308, a memory 1309, and a processor 1310. Those knowledgeable in the field may understand that the 1300 terminal can also include a power source (e.g., a battery) that supplies power to the components, and the power source can be logically connected to the 1310 processor through a power management system. In this way, functions such as charge management, discharge management, and power consumption management are implemented using the power management system. The terminal structure shown in Figure 13 does not constitute a limitation. The terminal may include more or fewer components than those shown in Figure 13, or a combination of some components, or the components may be arranged differently. These details are not described again here. It may be understood that in this embodiment of this application, the input unit 1304 may include a graphics processing unit (GPU) 13041 and a microphone 13042. The graphics processing unit 13041 processes image data from a still image or video obtained by an image capture device (such as a camera) in either video capture mode or image capture mode. The display unit 1306 may include a display panel 13061, and the display panel 13061 may be configured as a liquid crystal display, an organic light-emitting diode, or similar. The user input unit 1307 may include a touch panel 13071 and other input devices 13072. The touch panel 13071 is also known as a touchscreen. The touch panel 13071 may include two parts: a touch-sensing device and a touch controller.Other 13072 input devices may include, but are not limited to, a physical keyboard, a function key (such as a volume control key or a power button), a trackball, a mouse, a joystick, and the like. Details are not described here. In this application mode, radio frequency unit 1301 receives downlink data from a network-side device and then sends the downlink data to processor 1310 for processing; it also sends uplink data to the network-side device. Radio frequency unit 1301 typically includes, but is not limited to, the following components: RAQC ίΠ / ZZΖηZ / E / YΙΛΙ limits itself to an antenna, at least one amplifier, one transceiver, one coupler, one low-noise amplifier, one duplexer and the like. The 1309 memory module can be configured to store software programs or instructions and various data. It typically includes a program or instruction storage area and a data storage area. The program or instruction storage area can store an operating system, an application program, or instructions required by at least one function (such as a sound playback or image playback function). Additionally, the 1309 memory module may include high-speed random-access memory and non-volatile memory.Non-volatile memory can be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or flash memory, for example, at least a disk storage device, a flash memory device, or another volatile solid-state storage device. The 1310 processor may include one or more processing units. Optionally, an application processor and a modem processor may be integrated into the 1310 processor. The application processor primarily processes an operating system, user interfaces, application programs or instructions, and the like. The modem processor primarily processes radio communication, for example, by being a baseband processor. It can be understood that the modem processor may alternatively not be integrated into the 1310 processor. The 1301 radio frequency unit is configured to receive a multicast air interface resource, where the multicast air interface resource is reserved by a device on the target network side in case multicast QoS information is received from an MB NF. The multicast air interface resource is used for the terminal to receive multicast service data in a switched target mode, and the multicast QoS information corresponds to the multicast service data. In this mode of this request, the terminal receives the multicast air interface resource, where the multicast air interface resource is reserved by the device on the target network side in case the multicast QoS information is received from the MB NF, so that the terminal can switch from a PDU session mode to the target mode and receive the multicast service data using the multicast air interface resource, thus improving the efficiency of the mode change. RAQC ίΠ / ΖΖηΖ / Ε / ΥΙΛΙ Specifically, one modality of this application further provides a network-side device. As shown in Figure 14, the network-side device 1400 includes an antenna 141, a radio frequency apparatus 142, and a baseband apparatus 143. The antenna 141 is connected to the radio frequency apparatus 142. In an uplink direction, the radio frequency apparatus 142 receives information using the antenna 141 and sends the received information to the baseband apparatus 143 for processing. In a downlink direction, the baseband apparatus 143 processes the information to be sent and sends the information to the radio frequency apparatus 142; and the radio frequency apparatus 142 processes the received information and then sends the information using the antenna 141. The radio frequency apparatus 142 may be located in the baseband apparatus 143. The method carried out by the network-side device in the above modalities may be implemented in the baseband apparatus 143, and the baseband apparatus 143 includes a processor 144 and a memory 145. The baseband apparatus 143 may include, for example, at least one baseband processing unit, where a plurality of chips are arranged in the baseband processing unit. As shown in Figure 14, one of the chips is, for example, the processor 144, and is connected to memory 145, to invoke a program in memory 145 to perform the network-side device operation shown in the mode of the preceding method. The baseband apparatus 143 may further include a network interface 146, configured to exchange information with the radio frequency apparatus 142, where the interface is, for example, a common public radio interface (CPRI for short). Specifically, the network-side device in this embodiment of the present invention further includes: an instruction or program stored in memory 145 and capable of execution by the processor 144. The processor 144 invokes the instruction or program in memory 145 to execute the method implemented by the modules shown in Figures 2 through 6, achieving the same technical effects. To avoid repetition, the details are not repeated here. One embodiment of this application further provides a readable storage medium, where the readable storage medium stores a program or instructions. When the program or instructions are executed by a processor, the procedures of the preceding embodiments of the mode-switching method can be implemented, achieving the same technical effects. To avoid repetition, the details are not described again here. The processor is a processor in the terminal described in the previous modes. The readable storage medium includes a computer-readable storage medium, for example, a computer's read-only memory (ROM), a memory RAQC ίη / 77Π7 / Ε / ΥΙΛΙ of random access (Random Access Memory, RAM), a magnetic disk or an optical disk. One embodiment of this application also provides a chip, wherein the chip includes a processor and a communications interface. The communications interface is coupled to the processor, and the processor is configured to execute a program or instructions to implement the procedures of the previous embodiments of the mode-switching method, achieving the same technical effects. To avoid repetition, the details are not described again here. It should be understood that the chip mentioned in the modalities of this application may also be called a system-level chip, system chip, system-on-a-chip, or similar. It should be noted that the terms "include," "comprise," or any of their variants are intended to cover a non-exclusive inclusion, such that a procedure, method, article, or apparatus that includes a list of elements not only includes those elements but also includes other elements not expressly listed, or includes elements inherent in the procedure, method, article, or apparatus. In the absence of further restrictions, an element preceded by "includes a..." does not preclude the existence of other identical elements in the procedure, method, article, or apparatus that includes the element. Additionally, it may be observed that the scope of the method and apparatus in the modalities of this application is not limited to performing the functions in a shown or described order, but may also include performing the functions in a substantially simultaneous manner or in a reverse order, depending on the functions involved.For example, the methods described can be performed in a different order, and steps can be added, omitted, or combined. Furthermore, features described with reference to some examples can be combined in other examples. According to the preceding description of the implementations, a person skilled in the art can clearly understand that the methods in the above modalities can be implemented using software in combination with a necessary common hardware platform, and certainly can be implemented alternatively using hardware. However, in most cases, the former implementation is preferred. Based on this understanding, the technical solutions of the present invention, essentially, or the part that contributes to the prior art, can be implemented in the form of a software product.The software product is stored on a storage medium (such as ROM / RAM, a magnetic disk, or an optical disk), and includes several instructions to instruct a terminal (which may be a mobile phone, a computer, a server, an air conditioner, a network device, or similar) to perform the methods described in the modalities of this description. The above described the modalities of this application with reference to the attached drawings. However, this application is not limited to the specific modalities described above. RAQC ίΠ / ΖΖηΖ / Ε / ΥΙΛΙ The specific methods described above are merely illustrative and not restrictive. As mentioned in this application, those skilled in the art may develop many other methods without departing from the principles of this application and the scope of protection of the claims, and all such methods fall within the scope of protection of this application.

Claims

1. A mode-switching method, applied to a target device on the network side, wherein the method comprises: reserving a multicast air interface resource in case multicast QoS quality of service information is received from a multicast MB NF transmission network function, wherein the multicast air interface resource is used for a terminal to receive multicast service data in a switched target mode, and the multicast QoS information corresponds to the multicast service data; and sending the multicast air interface resource to a source network-side device or to the MB NF.

2. The method according to claim 1, further characterized in that, prior to reserving a multicast air interface resource, the method further comprises: receiving protocol data unit PDU session identification information from the source network-side device; and sending the PDU session identification information to the MB NF.

3. The method according to claim 1, further characterized in that, prior to reserving a multicast air interface resource, the method further comprises: receiving, from the device on the source network side, at least one of the following: a mode change indication; and the target mode.

4. The method according to claim 3, further characterized in that the mode change indication comprises a specific QoS flow identifier.

5. The method according to claim 2, further characterized in that the method further comprises: receiving, from the MB NF, at least one of the following: a QoS parameter corresponding to the PDU session; and multicast information.

6. The method according to claim 1, further characterized in that, prior to reserving a multicast air interface resource, the method further comprises: receiving, from the MB NF, at least one of the following: a mode change indication; the target mode; a QoS parameter corresponding to the PDU session; and multicast information. 7 - The method according to claim 5 or 6, further characterized in that in the event that the QoS parameter corresponding to the PDU session is received, the method further comprises: reserving an air interface resource for the PDU session.

8. The method according to claim 1, further characterized in that the method further comprises: sending to the MB NF at least one of the following: an air interface resource for a PDU session; and a multicast downlink tunnel resource for RAQC ίΠ / ZZΖηZ / E / YΙΛΙ to receive the multicast service data.

9. The method according to claim 8, further characterized in that the method further comprises: receiving the multicast service data using the multicast downlink tunnel resource; and sending the multicast service data to the terminal using the multicast air interface resource.

10. A mode-switching method, applied to an MB NF, wherein the method comprises: sending multicast QoS information to a target network-side device, wherein the multicast QoS information is used for the target network-side device to reserve a multicast air interface resource, the multicast air interface resource is used for a terminal to receive multicast service data in a switched target mode, and the multicast QoS information corresponds to the multicast service data.

11. The method according to claim 10, further characterized in that the method additionally comprises: receiving the multicast air interface resource.

12. The method according to claim 10, further characterized in that the method further comprises: receiving PDU session identification information from the target network-side device, wherein the PDU session identification information is sent by a source network-side device to the target network-side device.

13. The method according to claim 12, further characterized in that the method further comprises: sending to the target device on the network side at least one of the following: a QoS parameter corresponding to the PDU session; and multicast information.

14. The method according to claim 10, further characterized in that the method further comprises: sending to the target device on the network side at least one of the following: a mode change indication; the target mode; a QoS parameter corresponding to the PDU session; and multicast information.

15. The method according to claim 10, further characterized in that the method further comprises: receiving, from the target device on the network side, at least one of the following: an air interface resource for a PDU session; and a multicast downlink tunnel resource for sending the multicast service data. 16.- The method according to claim 15, further characterized in that the method further comprises: sending the multicast service data using the multicast downlink tunnel resource.

17. A mode-switching method applied to a device on the source network side, wherein the method comprises: receiving a multicast air interface resource, wherein the multicast air interface resource is reserved by a device on the target network side in the event that multicast QoS information is received from an MB NF, the multicast air interface resource is used for a terminal to receive multicast service data in a switched target mode, and the multicast QoS information corresponds to the multicast service data.

18. The method according to claim 17, further characterized in that the method additionally comprises: sending PDU session identification information to the target device on the network side.

19. A mode-switching method applied to a terminal, wherein the method comprises: receiving a multicast air interface resource, wherein the multicast air interface resource is reserved by a device on the target network side in case multicast QoS information is received from an MB NF, the multicast air interface resource is used for the terminal to receive multicast service data in a switched target mode, and the multicast QoS information corresponds to the multicast service data.

20. A mode-switching apparatus, wherein the apparatus comprises: a resource reservation module, configured to reserve a multicast air interface resource in the event that multicast QoS information is received from an MB NF, wherein the multicast air interface resource is used for a terminal to receive multicast service data in a switched target mode, and the multicast QoS information corresponds to the multicast service data; and a forwarding module, configured to forward the multicast air interface resource to a device on the source network side or to the MB NF.

21. A mode-changing apparatus, wherein the apparatus comprises: a sending module, configured to send multicast QoS information to a target network-side device, wherein the multicast QoS information is used for the target network-side device to reserve a multicast air interface resource, the multicast air interface resource is used for a terminal to receive multicast service data in a switched target mode, and the multicast QoS information corresponds to the multicast service data. 22 - A mode-changing apparatus, wherein the apparatus comprises: a receiving module, configured to receive a multicast air interface resource, wherein the multicast air interface resource is reserved by a device on the target network side in the event that multicast QoS information is received from an MB NF, the multicast air interface resource is used for a terminal to receive multicast service data in a changed target mode, and the multicast QoS information corresponds to the multicast service data.

23. A mode-changing apparatus, wherein the apparatus comprises: a receiving module, configured to receive a multicast air interface resource, wherein the RAQC ίη / 77Π7 / E / YΙΛΙ multicast air interface resource is reserved by a device on the target network side in the event that multicast QoS information is received from an MB NF, the multicast air interface resource is used for the apparatus to receive multicast service data in a changed target mode, and the multicast QoS information corresponds to the multicast service data. 24.- A terminal, comprising a processor, a memory and a program or instructions stored in the memory and capable of being executed by the processor, wherein when the program or instructions are executed by the processor, the mode-changing method of claim 19 is implemented.

25. A network-side device comprising a processor, a memory, and a program or instructions stored in the memory and capable of execution by the processor, wherein when the program or instructions are executed by the processor, the mode-changing method of any of claims 1 to 18 is implemented.

26. A readable storage medium, wherein the readable storage medium stores a program or instructions, and when the program or instructions are executed by a processor, the mode-changing method of any of claims 1 to 18, or the mode-changing method as implemented in claim 19, is implemented. 27 - A computer program product, wherein the program product is stored on a non-volatile storage medium, and the program product is executed by at least one processor to implement the mode-switching method of any of claims 1 to 18 or the mode-switching method according to claim 19.

28. An electronic device, wherein the electronic device is configured to execute the mode-changing method of any of claims 1 to 18 or the mode-changing method of claim 19.

29. A chip, wherein the chip comprises a processor and a communications interface, the communications interface is coupled to the processor and the processor is configured to execute a program or instructions to implement the mode-switching method of any of claims 1 to 18 or the mode-switching method of claim 19.

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