WO2020103807A1 - 一种通信方法及装置 - Google Patents

一种通信方法及装置

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Publication number
WO2020103807A1
WO2020103807A1 PCT/CN2019/119293 CN2019119293W WO2020103807A1 WO 2020103807 A1 WO2020103807 A1 WO 2020103807A1 CN 2019119293 W CN2019119293 W CN 2019119293W WO 2020103807 A1 WO2020103807 A1 WO 2020103807A1
Authority
WO
WIPO (PCT)
Prior art keywords
access network
network device
data packet
terminal
target access
Prior art date
Application number
PCT/CN2019/119293
Other languages
English (en)
French (fr)
Inventor
吴义壮
张万强
Original Assignee
华为技术有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 华为技术有限公司 filed Critical 华为技术有限公司
Priority to EP19887363.0A priority Critical patent/EP3869862A4/en
Priority to AU2019382639A priority patent/AU2019382639B9/en
Publication of WO2020103807A1 publication Critical patent/WO2020103807A1/zh
Priority to US17/323,572 priority patent/US20210274407A1/en

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/0005—Control or signalling for completing the hand-off
    • H04W36/0055—Transmission or use of information for re-establishing the radio link
    • H04W36/0066—Transmission or use of information for re-establishing the radio link of control information between different types of networks in order to establish a new radio link in the target network
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/08—Reselecting an access point
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/0005—Control or signalling for completing the hand-off
    • H04W36/0011—Control or signalling for completing the hand-off for data sessions of end-to-end connection
    • H04W36/0016—Hand-off preparation specially adapted for end-to-end data sessions
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/0005—Control or signalling for completing the hand-off
    • H04W36/0011—Control or signalling for completing the hand-off for data sessions of end-to-end connection
    • H04W36/0022—Control or signalling for completing the hand-off for data sessions of end-to-end connection for transferring data sessions between adjacent core network technologies
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/02—Buffering or recovering information during reselection ; Modification of the traffic flow during hand-off
    • H04W36/026—Multicasting of data during hand-off
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/08—Reselecting an access point
    • H04W36/087—Reselecting an access point between radio units of access points
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/16—Performing reselection for specific purposes
    • H04W36/18—Performing reselection for specific purposes for allowing seamless reselection, e.g. soft reselection
    • H04W36/185—Performing reselection for specific purposes for allowing seamless reselection, e.g. soft reselection using make before break
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/24—Reselection being triggered by specific parameters
    • H04W36/30—Reselection being triggered by specific parameters by measured or perceived connection quality data
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/24—Reselection being triggered by specific parameters
    • H04W36/30—Reselection being triggered by specific parameters by measured or perceived connection quality data
    • H04W36/304—Reselection being triggered by specific parameters by measured or perceived connection quality data due to measured or perceived resources with higher communication quality

Definitions

  • the embodiments of the present application relate to the field of communication technologies, and in particular, to a communication method and device.
  • the source base station may switch the terminal to the target base station, so that the target base station provides services for the terminal.
  • the source base station Before the terminal successfully switches from the source base station to the target base station, the source base station still sends downlink data packets to the terminal.
  • the signal quality of the air interface may be poor, and the reliability of the downlink data packet received before the terminal is successfully handed over to the target base station cannot be guaranteed.
  • the source base station starts sending the terminal's downlink data packet to the target base station after sending the handover command to the terminal, which may cause the target base station to not receive the The downlink data packet of the terminal of the source base station prevents it from sending the downlink data packet to the terminal immediately, which in turn causes a problem of large handover delay.
  • the 5G system needs to provide a service that supports high reliability and low latency communications (Ultra Reliable and Low Latency Communications, URLLC).
  • URLLC Ultra Reliable and Low Latency Communications
  • the handover process also needs to ensure high reliability and low latency. Therefore, the handover process in the prior art cannot meet the high reliability and low latency requirements of the URLLC service.
  • Embodiments of the present application provide a communication method and device, which are used to improve the reliability and reduce the delay of downlink data received by a terminal during switching of an access network device.
  • an embodiment of the present application provides a communication method, including: a source access network device sends a first data packet sent to a terminal to a target access network device.
  • a source access network device determines that the target access network device receives the first data packet, the source access network device sends a first message to the terminal instructing the terminal to switch to the target access network device.
  • Embodiments of the present application provide a communication method. Since the terminal switches to the target access network device (that is, before the source access network device sends the first message to the terminal), the source access network device still needs to send the first data The packet is sent to the terminal. If the signal quality of the air interface is poor during the handover process, the terminal may not receive the first data packet. Therefore, the source access network device sends the first data packet to the target access network device, so that when the source access network device determines that the target access network device receives the first data packet, it sends an instruction to the terminal to switch the terminal to the target The first message of the access network device. On the one hand, the first data packet can be provided at the target access network device.
  • sending the first message to the terminal may enable the target to connect to the target access network device after the terminal successfully switches from the source access network device to the target access network device.
  • the network access device sends the first data packet to the terminal again. This can ensure that the terminal cannot obtain the first data packet from the source access network device during the handover process, and can also obtain the first data packet from the target access network device, thereby ensuring the reliability of data transmission.
  • the delay can be further reduced.
  • the method provided in this embodiment of the present application further includes: the source access network device receives first information from the target access network device indicating that the terminal is allowed to switch to the target access network device, the source The access network device sends the first data packet to the target access network device. That is, the source access network device receives the first information that allows handover, and the source access network device sends the first data packet to the target access network device.
  • the method provided in this embodiment of the present application further includes: the source access network device determines the target according to the first information
  • the access network device allows the terminal to switch to the target access network device.
  • the source access network device determines that the target access network device agrees to the handover, it starts to send the first data packet, which can avoid waste of air interface resources caused by blindly sending the first data packet because the target access network device does not agree to the handover.
  • the first data packet includes a copy data packet
  • the method provided in this embodiment of the present application further includes: the source access network device obtains the copy data packet; or, when it is satisfied that the terminal switches the access network device At the condition, the source access network device obtains the copy data packet.
  • the source access network device obtaining the copy data packet includes: the source access network device copying the data packet that meets the preset condition in the data packet of the terminal to obtain the copy data packet.
  • the data packet satisfying the preset condition includes at least one of the following cases: a data packet using a preset quality of service QoS flow, a data packet on a preset packet data unit PDU session, and a packet loss rate less than or equal to a preset gate Data packets with limit values, or data packets on preset radio bearers.
  • the data packet to be copied can be selected according to the preset condition, so as to ensure the reliability of the data packet satisfying the preset condition first.
  • the source access network device obtaining the duplicate data packet includes: the source access network device replicates the terminal's data packet to obtain the duplicate data packet.
  • the method provided in this embodiment of the present application further includes: the source access network device determines that the condition for switching the access network device for the terminal is met, and the source access network device performs the above-mentioned copying step.
  • the method provided by the embodiment of the present application further includes: the source access network device sends the serial number SN status information to the target access network device, and the SN status information is used by the target access network device to send to the terminal data pack. It is convenient for the target access network device to set the SN of the data packet by sending the SN status information.
  • the source access network device determining that the target access network device receives the first data packet includes: the source access network device receives the second message sent by the target access network device, and the second message is used To indicate that the target access network device receives the first data packet; or, the source access network device determines that the target access network device receives the first data packet according to the delay information.
  • the method provided in this embodiment of the present application further includes: the source access network device determines delay information according to the QoS information of the first data packet; or, the source access network device obtains from the session management function Delay information.
  • an embodiment of the present application provides a communication method, including: the target access network device sending first information indicating that the terminal is allowed to switch to the target access network device to the source access network device; the target access network device Receive the first data packet from the terminal of the source access network device; when the terminal successfully switches from the source access network device to the target access network device, the target access network device sends the first data packet to the terminal.
  • the method provided in the embodiment of the present application further includes: the target access network device sending a second message indicating to the source access network device that the target access network device received the first data packet.
  • the method provided by the embodiment of the present application further includes: the target access network device receives the serial number SN status information from the source access network device, and the SN status information is used by the target access network device to the terminal Send a data packet; the target access network device processes the data packet that does not carry the SN from the source access network device according to the SN status information and obtains a second data packet; the data packet that does not carry the SN is the first data packet Data packet of the terminal or the data packet of the terminal in the source access network device; the target access network device sends a second data packet to the terminal.
  • the SN of the second data packet is determined according to the SN status information.
  • an embodiment of the present application provides a communication device, which can implement the communication method described in the first aspect or any possible implementation manner of the first aspect, and therefore can also implement the first aspect or The beneficial effects in any possible implementation manner of the first aspect.
  • the communication apparatus may be a source access network device, or may be an apparatus in the source access network device that can support the first aspect or any possible implementation manner of the first aspect.
  • a chip used in a source access network device may implement the above method through software, hardware, or through hardware to execute corresponding software.
  • the communication device includes a sending unit and a processing unit.
  • the sending unit is configured to send the first data packet of the terminal to the target access network device.
  • the sending unit is further configured to send a first message for instructing the terminal to switch to the target access network device when the processing unit determines that the target access network device receives the first data packet.
  • the communication apparatus further includes: a receiving unit, configured to receive first information from the target access network device indicating that the terminal is allowed to switch to the target access network device; and a sending unit, also used to Send the first data packet of the terminal to the target access network device.
  • the first data packet includes a duplicate data packet
  • the processing unit is further used to obtain the duplicate data packet; or, the processing unit is also used when the condition for switching the access network device for the terminal is satisfied At that time, get a copy packet.
  • the processing unit is further specifically used to copy the data packets that satisfy the preset condition among the data packets of the terminal to obtain the copied data packet.
  • the data packet satisfying the preset condition includes at least one of the following cases: a data packet using a preset quality of service QoS flow, a data packet on a preset packet data unit PDU session, and a packet loss rate less than or equal to a preset gate Data packets with limit values, or data packets on preset radio bearers.
  • the processing unit is further specifically used to copy the data packet of the terminal to obtain the copied data packet.
  • the processing unit is further configured to determine that the condition for switching the access network device for the terminal is satisfied, and perform the above-mentioned copying step.
  • the sending unit is further configured to send the serial number SN status information to the target access network device, and the SN status information is used to send the data packet to the terminal by the target access network device.
  • the receiving unit is configured to receive a second message sent by the target access network device to indicate that the target access network device receives the first data packet, and the receiving unit is specifically configured to Message, it is determined that the target access network device receives the first data packet.
  • the processing unit is configured to determine that the target access network device receives the first data packet according to the delay information. This is convenient for the source access network device to determine that the target access network device receives the first data packet through multiple channels.
  • the processing unit is further configured to determine the delay information according to the QoS information of the first data packet; or, the processing unit is further configured to obtain the delay information from the network element of the session management function.
  • a communication apparatus provided in an embodiment of the present application may be a source access network device or a chip applied in the source access network device.
  • the communication apparatus includes: a communication interface and one or Multiple processors.
  • the source access network device communicates with other devices through a communication interface.
  • the source access network device performs the communication method as described in the first aspect above.
  • the communication interface is used to support the communication device to perform the steps described in any possible implementation manner of the first aspect to the first aspect for receiving / transmitting messages / data on the side of the communication device.
  • the processor is configured to support the communication device to perform the steps of message / data processing on the side of the communication device described in any possible implementation manner of the first aspect to the first aspect.
  • the communication interface and the processor of the communication device are coupled to each other.
  • the communication device may further include a memory for storing computer program code, and the computer program code includes instructions.
  • the processor, communication interface and memory are coupled to each other.
  • an embodiment of the present application provides a communication device, which can implement the second aspect or a communication method described in any possible implementation manner of the second aspect, and therefore can also implement the second aspect or The beneficial effects in any possible implementation manner of the second aspect.
  • the communication device may be a target access network device, or may be a device that can support the target access network device to implement the second aspect or any possible implementation manner of the second aspect.
  • a chip used in a target access network device may implement the above method through software, hardware, or through hardware to execute corresponding software.
  • a communication apparatus includes: a sending unit, configured to send, to a source access network device, first information indicating that a terminal is allowed to switch to a target access network device.
  • the receiving unit is configured to receive the first data packet from the terminal of the source access network device.
  • the sending unit is configured to send the first data packet to the terminal when the terminal successfully switches from the source access network device to the target access network device.
  • the sending unit is further configured to send a second message indicating to the source access network device that the target access network device received the first data packet.
  • the receiving unit is further configured to receive serial number SN status information from the source access network device, and the SN status information is used by the target access network device to send a data packet to the terminal.
  • the sending unit is further configured to process the data packet from the source access network device that does not carry the SN according to the SN status information and obtain a second data packet; the data packet that does not carry the SN is the data packet or source in the first data packet.
  • the data packet of the terminal in the access network device and the sending unit are also used to send the second data packet to the terminal.
  • a communication device provided in an embodiment of the present application may be a target access network device or a chip applied in the target access network device.
  • the communication device includes: a communication interface and one or Multiple processors.
  • the target access network device communicates with other devices through a communication interface.
  • the target access network device executes the communication method described in the second aspect above.
  • the communication interface is used to support the communication device to perform the steps of receiving / transmitting messages / data on the side of the communication device described in any possible implementation manner of the second aspect to the second aspect.
  • the processor is used to support the communication device to perform the steps of performing message / data processing on the side of the communication device described in any possible implementation manner of the second aspect to the second aspect.
  • the communication interface and the processor of the communication device are coupled to each other.
  • the communication device may further include a memory for storing computer program code, and the computer program code includes instructions.
  • the processor, communication interface and memory are coupled to each other.
  • an embodiment of the present application provides a computer-readable storage medium that stores instructions, and when the instructions run on a computer, the computer is allowed to execute the first aspect or various possibilities of the first aspect A communication method described in the implementation.
  • the present application provides a computer-readable storage medium having instructions stored therein, which when executed on a computer, causes the computer to perform the second aspect or various possible implementations of the second aspect A communication method described in the way.
  • the present application provides a computer program product that includes instructions, which when executed on a computer, causes the computer to perform a communication method described in the first aspect or various possible implementation manners of the first aspect.
  • the present application provides a computer program product including instructions, which when executed on a computer, causes the computer to perform a communication method described in the second aspect or various possible implementation manners of the second aspect.
  • an embodiment of the present application provides a chip, the chip includes a processor and a communication interface, and the communication interface is coupled to the processor.
  • the processor is used to run a computer program or instructions to implement the first aspect or various aspects of the first aspect.
  • the communication interface is used to communicate with other modules than the chip.
  • an embodiment of the present application provides a chip including a processor and a communication interface.
  • the communication interface is coupled to the processor.
  • the processor is used to run a computer program or instruction to implement the second aspect or various aspects of the second aspect.
  • the communication interface is used to communicate with other modules than the chip.
  • an embodiment of the present application provides a communication system.
  • the method includes: the third aspect and the source access network device described in various possible implementation manners of the third aspect, and the fourth aspect and the fourth aspect.
  • Various possible implementations describe the target access network equipment.
  • FIGS. 1 to 4 are schematic diagrams of a communication system provided by embodiments of the present application.
  • 5 is a schematic diagram of a 5G communication system provided by an embodiment of this application.
  • FIG. 6 is a schematic diagram of another 5G communication system provided by an embodiment of the present application.
  • FIG. 7 is a schematic structural diagram of a base station according to an embodiment of this application.
  • FIG. 8 is a schematic structural diagram of another base station according to an embodiment of the present application.
  • FIG. 9 is a schematic diagram of another communication system provided by an embodiment of the present application.
  • FIG. 10 is a schematic structural diagram of an access network device according to an embodiment of this application.
  • FIG. 11 is a schematic flowchart 1 of a communication method according to an embodiment of the present application.
  • FIG. 12 is a schematic diagram of a data packet transmission provided by an embodiment of the present application.
  • FIG. 13 is a second schematic flowchart of a communication method according to an embodiment of the present application.
  • FIG. 14 is a third schematic flowchart of a communication method according to an embodiment of the present application.
  • 15 is a fourth schematic flowchart of a communication method according to an embodiment of the present application.
  • 16 is a schematic flowchart of a specific embodiment provided by an embodiment of the present application.
  • FIG. 17 is a schematic flowchart of another specific embodiment provided by an embodiment of the present application.
  • 18-21 are schematic structural diagrams of a communication device provided by an embodiment of the present application.
  • 22 is a schematic structural diagram of a chip provided by an embodiment of the present application.
  • GSM global system for mobile communication
  • E-UTRA evolved universal wireless terrestrial access
  • UMTS universal mobile communication system
  • LTE long term evolution
  • 5G 5th-generation
  • NR new radio
  • At least one refers to one or more, and “multiple” refers to two or more.
  • “And / or” describes the relationship of the related objects, indicating that there can be three relationships, for example, A and / or B, which can mean: A exists alone, A and B exist at the same time, B exists alone, where A, B can be singular or plural.
  • the character “/” generally indicates that the related object is a "or” relationship.
  • “At least one of the following” or a similar expression refers to any combination of these items, including any combination of a single item or a plurality of items.
  • At least one item (a) in a, b, or c can represent: a, b, c, ab, ac, bc, or abc, where a, b, c can be a single or multiple .
  • a or B may indicate that A exists alone, A and B exist simultaneously, and B exists alone, where A and B may be singular or plural.
  • the words “first” and “second” are used to distinguish the same or similar items that have substantially the same functions and functions. Those skilled in the art may understand that the words “first” and “second” do not limit the number and execution order, and the words “first” and “second” do not necessarily mean different.
  • the evolved base station evolved Node (Base) Station (eNB) in the LTE system (which can be called LTE eNB) communicates with the 4G core network (for example, Evolved Packet Core (EPC)) through the S1 interface Connection, between different LTE eNBs through X2 interface.
  • LTE eNB1 and LTE eNB2 are connected through an X2 interface.
  • Figure 1 shows the network architecture of the LTE system, where the X2 interface supports direct transmission of data and signaling between two LTE eNBs.
  • the X2 interface is also divided into two interfaces, for example, an X2-C interface and an X2-U interface.
  • the X2-C interface is used for the control plane
  • the X2-U interface is used for the user plane.
  • the X2-C interface is used to transmit LTE signaling between eNBs.
  • the X2-U interface is used to transmit data between LTE and eNB.
  • the terminal performs data transmission or signaling transmission with the EPC through the LTE eNB to which they respectively access.
  • 4G networks have gradually evolved to 5G networks.
  • the LTE system can evolve into an eLTE system.
  • the EPC network and the Next-Generation Core (NG-Core) network coexist.
  • the eNB in the eLTE system is called eLTE eNB, and the terminal with access to the NG-Core network function is called the next-generation terminal (for example, terminal 1 and terminal 2 in the figure).
  • the eLTE eNB can access the EPC network and the NG-Core network.
  • the terminal 1 wirelessly connected to the eLTE eNB can access the EPC network or the NG-Core network through the eLTE eNB. As shown in FIG.
  • the eLTE eNB is connected to the EPC network through the S1 interface, and can also be connected to the NG-Core network through other corresponding interfaces (denoted by NG in FIG. 2).
  • the terminal 1 connected to the eLTE eNB can access the EPC network through the eLTE eNB, and can also access the NG-Core network through the eLTE eNB.
  • Terminals connected to eLTE eNB can access the EPC network through LTE eNB.
  • NRgNB is used to indicate a base station that is only connected to the NG-Core network.
  • LTE and eNB are connected through the X2 interface, and eLTE and NR are connected through the Xn interface.
  • the core network equipment of the 4G network can communicate with the core network equipment of the 5G network (English: interworking).
  • the composition structure of each device in the communication system of the 5G network in a scenario where the core network device of the 4G network and the core network device of the 5G network communicate with each other.
  • Core network devices have user plane functions and control plane functions.
  • user plane network elements are used to indicate devices that can implement the user plane functions of the core network devices
  • control plane network elements are used to indicate devices that can implement the control plane functions of the core network devices.
  • the user plane network element and the control plane network element can be integrated in the same device or can be set independently. In the embodiments of the present application, the user plane network element and the control plane network element are independently set as an example for description.
  • the home subscriber server (HSS) of the 4G network is integrated with the unified data management (UDM) network element of the 5G network in the same device, and the public data network gateway (Public) of the 4G network (Network) Gateway, PGW) control plane PGW-C network element and 5G network session management function (Session Management Function, SMF) network element integrated in the same device, 4G network PGW-U network element and 5G network user plane function (User plane (Function, UPF) network elements are integrated on the same device.
  • the Mobility Management Entity (MME) in FIG. 3 is the control plane network element of the 4G network, and the MME and LTE eNB are connected through the S1-MME interface.
  • the core access and mobility management function (Core Access and Mobility Management Function, AMF) network element is the control plane network element in the 5G network.
  • the AMF network element is connected to the NR gNB / eLTE eNB through the N2 interface, and the terminal 3 through the N1 interface connection.
  • the MME and the AMF network element may be connected through an Nx interface, or the Nx interface may not exist. Therefore, the dotted line in FIG. 3 indicates the Nx interface.
  • the AMF network element and the PCF network element are connected through the N15 interface
  • the PGW-C network element and the SMF network element are connected to the PCF network element through the N7 interface.
  • a serving gateway (Serving Gateway, SGW) is a device in charge of routing and forwarding processing of data packets in a 4G network.
  • Fig. 3 also shows related interfaces such as S5-U, S5-C, S11, S1-U, S6a, N1, N2, N3, N4, N7, N8, N10, N11, N15, etc. Describe these interfaces in detail.
  • each Next Generation Node B (gNB) in the NR system which is called NRgNB in the embodiment of this application, is connected to the NG-Core network through the N2 interface.
  • NR and gNB are connected through the Xn interface, for example, gNB1 and gNB2 are connected through the Xn interface.
  • Each NRgNB is connected to at least one terminal in the NR system.
  • Figure 4 shows the network architecture of the NR system. In practical applications, the connection between the above-mentioned multiple devices is a wireless connection. In order to conveniently and intuitively indicate the connection relationship between the various devices, solid lines are used in FIG. 4.
  • the network element or entity corresponding to gNB may be RAN, and the network element included in the NG-Core network may be SMF network element or UPF network.
  • the element and policy control network element can be (Policy Control Function, PCF), application function (Application Function, AF) network element, authentication server function (Authentication Server Function (AUSF) network element, UDM network element, network capability opening function ( Network Exposure Function (NEF) network element, network warehouse storage function (Network Repository Function, NRF) network element and data network (Data Network, DN), security anchor function (Security Anchor Function, SEAF) network element or network slice selection function (Network, Slice, Selection, Function, NSSF) network element, etc.
  • Policy Control Function PCF
  • application function Application Function
  • AUSF Authentication Server Function
  • UDM network element
  • network capability opening function Network Exposure Function (NEF) network element
  • NRF Network Repository Function
  • SEAF Security Anchor Function
  • SEAF Security Anchor Function
  • the terminal communicates with the AMF network element through the N1 interface (N1 for short).
  • the AMF network element communicates with the SMF network element through the N11 interface (N11 for short).
  • the SMF network element communicates with one or more UPF network elements through the N4 interface (N4 for short). Any two UPF network elements in one or more UPF network elements communicate through the N9 interface (N9 for short).
  • the UPF network element communicates with the Data Network (DN) through the N6 interface (N6 for short).
  • the terminal accesses the network through an access network device (for example, a RAN device).
  • the access network device communicates with the AMF network element through an N2 interface (N2 for short).
  • the SMF network element communicates with the PCF network element through the N7 interface (N7 for short), and the PCF network element communicates with the AF network element through the N5 interface.
  • the access network device communicates with the UPF network element through the N3 interface (N3 for short). Any two or more AMF network elements communicate through the N14 interface (N14 for short).
  • the SMF network element communicates with the UDM network element through the N10 interface (N10 for short).
  • the AMF network element communicates with the AUSF network element through the N12 interface (N12 for short).
  • the AUSF network element communicates with the UDM network element through the N13 interface (N13 for short).
  • the AMF network element communicates with the UDM network element through the N8 interface (N8 for short).
  • the access network device, AF network element, AMF network element, SMF network element, AUSF network element, UDM network element, UPF network element, and PCF network element in FIG. 5 are only a name, and the name is for the device itself. No limitation. In 5G networks and other networks in the future, the network elements corresponding to the access network equipment, AF network element, AMF network element, SMF network element, AUSF network element, UDM network element, UPF network element and PCF network element may also be Other names are not specifically limited in this embodiment of the present application.
  • the UDM network element may also be replaced with HSS or a user subscription database (User Subscription Database, USD) or database entity, etc., which will be uniformly described here, and will not be described in detail later.
  • FIG. 6 shows a 5G network with a non-roaming architecture based on a service interface.
  • the 5G network may also use a reference point-based non-roaming architecture as shown in FIG. 6.
  • the AMF network element belongs to the core network element and is mainly responsible for the signaling processing part, such as: access control, mobility management, attachment and detachment, and gateway selection.
  • the AMF network element provides services for the session in the terminal, it will provide the control plane storage resources for the session to store the session ID, the SMF network element ID associated with the session ID, and so on.
  • Radio Access Network ((Radio) Access Network ((R) AN) equipment including RAN equipment and AN equipment.
  • the RAN equipment is mainly a 3rd Generation Partnership Project (3GPP) network wireless network equipment
  • the AN may be a non-3GPP access network equipment.
  • 3GPP 3rd Generation Partnership Project
  • the access network device may include various forms of base stations, such as macro base stations, micro base stations (also called small stations), relay stations, and access points.
  • base stations such as macro base stations, micro base stations (also called small stations), relay stations, and access points.
  • the names of devices with base station functions may be different.
  • 5G 5th generation
  • LTE Long Term Evolution
  • eNB evolved Node B
  • eNodeB Node B
  • 3G 3rd generation
  • AN equipment Allow non-3GPP technology to interconnect and interoperate between the terminal and the 3GPP core network.
  • non-3GPP technologies include, for example, Wireless Fidelity (Wi-Fi), Worldwide Interoperability for Microwave Access (WiMAX), and Code Division Multiple Access (CDMA) networks.
  • Wi-Fi Wireless Fidelity
  • WiMAX Worldwide Interoperability for Microwave Access
  • CDMA Code Division Multiple Access
  • SMF network element responsible for user plane network element selection, user plane network element redirection, internet protocol (IP) address allocation, bearer establishment, modification and release, and QoS control.
  • IP internet protocol
  • UPF network element responsible for forwarding and receiving user data in the terminal.
  • User data can be received from the data network and transmitted to the terminal through the access network device.
  • the UPF network element can also receive user data from the terminal through the access network device and forward it to the data network.
  • the transmission resources and scheduling functions in the UPF network element serving the terminal are managed and controlled by the SMF network element.
  • PCF network element mainly supports the provision of a unified policy framework to control network behavior, provides policy rules to the network functions of the control layer, and is responsible for obtaining user contract information related to policy decisions.
  • AUSF network element mainly provides authentication and authentication functions.
  • NEF network element mainly supports the secure interaction between 3GPP networks and third-party applications. NEF network elements can safely open network capabilities and events to third parties to strengthen or improve application service quality. 3GPP networks can also be securely obtained from third parties Related data is used to enhance the intelligent decision of the network; at the same time, the NEF network element supports the restoration of structured data from the unified database or the storage of structured data in the unified database.
  • Unified database Mainly responsible for storing structured data.
  • the stored content includes contract data and policy data, externally exposed structured data and application-related data.
  • AF network element mainly supports interaction with the 3GPP core network to provide services. For example, it affects data routing decisions, policy control functions, or provides third-party services to the network side.
  • the terminal in the embodiment of the present application may be a device that provides voice and / or data connectivity to a user, a handheld device with a wireless connection function, or other processing devices connected to a wireless modem.
  • the wireless terminal can communicate with one or more core networks via the RAN.
  • the wireless terminal may be a user equipment (UE), a handheld terminal, a notebook computer, a subscriber unit, a cellular phone, a smart phone, a wireless data card, and a personal digital assistant (personal digital) assistant (PDA) computer, tablet computer, wireless modem (modem), handheld device (handheld), laptop (laptop computer), cordless phone (cordless phone) or wireless local loop (wireless local loop (WLL) station 2.
  • a certain air interface technology for example, 3GPP access technology or non-3GPP access technology is used for communication between the terminal and the access network device.
  • the future access network can be implemented using a cloud radio access network (C-RAN) architecture
  • C-RAN cloud radio access network
  • one possible way is to divide the protocol stack architecture and functions of the traditional base station into two parts, one part is called centralized Unit (CU), another part is called distributed unit (DU), and the actual deployment method of CU and DU is more flexible, for example, the CU parts of multiple base stations are integrated together to form a large-scale function entity.
  • FIG. 7 it is a schematic diagram of a network architecture provided by an embodiment of the present application.
  • the network architecture includes core network (CN) equipment and access network (RAN as an example) equipment.
  • the RAN equipment includes a baseband device and a radio frequency device.
  • the baseband device can be implemented by one node or multiple nodes.
  • the radio frequency device can be implemented independently from the baseband device, can also be integrated into the baseband device, or can be partly remote. Integrated in the baseband device.
  • a RAN device eNB
  • eNB includes a baseband device and a radio frequency device, where the radio frequency device can be remotely arranged relative to the baseband device (such as a radio remote unit (RRU) relative to the baseband processing unit ( building, base, unit (BBU)), the RAN equipment is implemented by a node, which is used to implement radio resource control (RRC), packet data convergence layer protocol (packet data, protocol, PDCP), radio link control (radio link control, RLC), media access control (medium access control, MAC) and other protocol layer functions.
  • RRC radio resource control
  • packet data convergence layer protocol packet data convergence layer protocol
  • PDCP radio link control
  • RLC radio link control
  • media access control medium access control
  • MAC media access control
  • the baseband device may include a CU and a DU, and multiple DUs may be centrally controlled by one CU.
  • CU and DU can be divided according to the protocol layer of the wireless network. For example, the functions of the protocol layer above the packet data aggregation layer are set at the CU, and the protocol layers below PDCP, such as the functions of the RLC layer and MAC layer Set in DU.
  • This division of the protocol layer is only an example, and it can also be divided at other protocol layers, for example, at the RLC layer, the functions of the RLC layer and above are set in the CU, and the functions of the protocol layers below the RLC layer are set in the DU; Or, in a certain protocol layer, for example, some functions of the RLC layer and the functions of the protocol layer above the RLC layer are set in the CU, and the remaining functions of the RLC layer and the functions of the protocol layer below the RLC layer are set in the DU. In addition, it can also be divided in other ways, for example, according to the delay, and the function that the processing time needs to meet the delay requirement is set in the DU, and the function that does not need to meet the delay requirement is set in the CU.
  • the radio frequency device can be remotely located, not placed in the DU, or integrated in the DU, or partially remotely and partially integrated in the DU, without any limitation here.
  • control plane (CP) and user plane (UP) of the CU can also be separated and implemented into different entities for control.
  • the data generated by the CU can be sent to the terminal through the DU, or the data generated by the terminal can be sent to the CU through the DU.
  • the DU can directly encapsulate the data through the protocol layer and pass it to the terminal or CU without parsing the data.
  • the data of the RRC or PDCP layer will eventually be processed as the data of the physical layer (PHY) and sent to the terminal, or it will be converted from the received data of the PHY layer.
  • the RRC or PDCP layer data can also be considered to be sent by the DU.
  • the CU is divided into access network devices in the RAN.
  • the CU may also be divided into access network devices in the CN, which is not limited herein.
  • the apparatus in the following embodiments of the present application may be located in a terminal or an access network device according to the functions it implements.
  • the access network device may be a CU node, or a DU node, or a RAN device including functions of the CU node and the DU node.
  • the access network device can be divided into CU or DU. As shown in FIG. 7, if an access network device covers one or more cells, it can refer to that the CU of the access network device covers one or more cells, or that the DU of the access network device covers one or more cells. .
  • the interface between the 5G core network (5G Core, 5GC) and each access network device is an NG interface, where the NG interface includes a control plane interface and a data plane interface.
  • the control plane interface is an N2 interface
  • the data plane interface is N3 interface.
  • FIG. 9 takes the access network device as a gNB as an example.
  • Switching from gNB1 to gNB2 may refer to switching from the CU of gNB1 to the CU of gNB2, or the CU from gNB1 to gNB2. Or switch from DU of gNB1 to DU of gNB2, or switch from DU of gNB1 to DU of gNB2.
  • a base station can generally cover one or more cells. Each cell has a certain coverage area, which is relatively fixed. If the terminal leaves the serving cell and enters another cell while moving, if the other cell and the serving cell are managed by different base stations (for example, the serving cell belongs to the source base station and the other cell belongs to the target base station). The terminal needs to be switched from the source base station to the target base station under the control of the existing mobility management technology.
  • the existing fifth-generation mobile communication technology handover process defines a handover process based on the Xn interface and a handover process based on N2.
  • the Xn interface is an interface between two access network devices, that is, the switching process of the Xn interface can be understood as that the source radio access network (Source Radio Access Network, S-RAN) device is determined as the terminal switching access network device
  • S-RAN source radio access network
  • T-RAN target Radio Access Network
  • the S-RAN device initiates a handover procedure to the terminal to switch the terminal to the T-RAN device.
  • N2 is the interface between the access network device and the AMF network element, that is, the switching process of N2 can be understood as: when the S-RAN device determines that the terminal switches the access network device, the S-RAN device moves to the S-AMF network Yuan sends a switch request. After the T-AMF network element is selected by the S-AMF network element, the T-AMF network element sends the handover request to the T-RAN device.
  • the handover request confirmation is sent to the -RAN device through the S-AMF network element, and the S-RAN device determines that the T-RAN device agrees to switch the terminal to T-RAN In the case of a device, the S-RAN device initiates a handover procedure to the terminal to switch the terminal to the T-RAN device.
  • the S-RAN device needs to send a downlink data packet to the terminal before determining to perform the handover process (ie, send the handover command to the terminal).
  • the S-RAN device may need to send the terminal's data packet to the terminal during the handover process, in the current handover process, the S-RAN device continues to send the terminal's data packet until the handover command is sent to the terminal when determining the handover.
  • the communication quality of the air interface may become poor. If the S-RAN device still sends data packets to the terminal during this process, there is a possibility that the terminal cannot receive the data packet sent by the S-RAN device because of poor communication quality, so the reliability of the data packet is reduced. And the S-RAN device sends the data packet to the T-RAN device after sending the handover command to the terminal, which results in a certain delay.
  • the embodiments of the present application provide a communication method, in which the source access network device copies the terminal data packet (for example, the source data packet) before sending the handover command to the terminal to obtain the copied data packet.
  • the source access network device then sends the copied data packet to the target access network device selected for the terminal.
  • the source access network device must continue to send the source data packet to the terminal.
  • the source access network device Before the terminal successfully switches from the source access network device to the target access network device, the source access network device still needs to send the source data packet to the terminal, and after the terminal successfully switches from the source access network device to the target access network device,
  • the target access network device may send the copied data packet obtained based on the source data packet to the terminal.
  • the terminal can also obtain the copied data packet from the target access network device, thereby ensuring the reliability of data transmission.
  • the data packet sent to the target access network device is before the handover command is sent to the terminal, this is compared with the prior art in which the data packet of the terminal is sent to the target access network device after the handover command is sent to the terminal. Can further reduce the delay.
  • FIG. 10 is a schematic diagram of the composition of an access network device provided by an embodiment of the present application.
  • the source access network device and the target access network device may refer to the structure of the access network device shown in FIG. 10.
  • the access network device may include at least one processor 41 and memory 42.
  • the processor 41 is a control center of the access network device, and may be a processor or a collective name of multiple processing elements.
  • the processor 41 is a CPU, and may also be a specific integrated circuit (Application Specific Integrated Circuit, ASIC), or one or more integrated circuits configured to implement the embodiments of the present application, for example, one or more micro-processing (Digital Signal Processor, DSP), or, one or more field programmable gate array (Field Programmable Gate Array, FPGA).
  • ASIC Application Specific Integrated Circuit
  • DSP Digital Signal Processor
  • FPGA Field Programmable Gate Array
  • the processor 41 can execute various functions of the access network device by running or executing the software program stored in the memory 42 and calling the data stored in the memory 42, for example, for performing the method embodiments of the present application Action of the source access network device or target access network device.
  • the processor 41 may include one or more CPUs, such as CPU 0 and CPU 1 shown in FIG. 10.
  • the access network device may include multiple processors, such as the processor 41 and the processor 45 shown in FIG. 10.
  • processors can be a single-core processor (single-CPU) or a multi-core processor (multi-CPU).
  • the processor here may refer to one or more devices, circuits, and / or processing cores for processing data (eg, computer program instructions).
  • the memory 42 may be a read-only memory (Read-Only Memory, ROM) or other types of static storage devices that can store static information and instructions, a random access memory (Random Access, Memory, RAM), or other types of information and instructions that can be stored
  • the dynamic storage device can also be electrically erasable programmable read-only memory (Electrically Erasable Programmable Read-Only Memory, EEPROM), read-only disc (Compact Disc Read-Only Memory, CD-ROM) or other disc storage, disc storage (Including compact discs, laser discs, optical discs, digital versatile discs, Blu-ray discs, etc.), magnetic disk storage media or other magnetic storage devices, or can be used to carry or store desired program code in the form of instructions or data structures and can be used by a computer Access to any other media, but not limited to this.
  • the access network device further includes: a bus 44.
  • the memory 42 may exist independently, and is connected to the processor 41 through the bus 44.
  • the memory 42 may also be integrated with the processor 41.
  • the memory 42 is used to store a software program that executes the solution of the present application.
  • the access network device further includes: a transceiver 43.
  • the transceiver 43 is used to communicate with other devices or communication networks. For example, it is used to communicate with terminals, core network equipment (for example, AMF network elements, SMF network elements, UPF network elements, etc.), Ethernet, RAN, wireless local area network (Wireless Local Area Areas, WLAN) and other communication networks.
  • the transceiver 43 may include all or part of the baseband processor, and may optionally include an RF processor.
  • the RF processor is used to send and receive RF signals
  • the baseband processor is used to process the baseband signal converted from the RF signal or the baseband signal to be converted into the RF signal.
  • the bus 44 may be an industry standard architecture (Industry Standard Architecture, ISA) bus, an external device interconnection (Peripheral Component Interconnect, PCI) bus, or an extended industry standard architecture (Extended Industry Standard, Architecture, EISA) bus, or the like.
  • ISA Industry Standard Architecture
  • PCI Peripheral Component Interconnect
  • EISA Extended Industry Standard Architecture
  • the bus can be divided into address bus, data bus, control bus and so on. For ease of representation, only a thick line is used in FIG. 10, but it does not mean that there is only one bus or one type of bus.
  • the device structure shown in FIG. 10 does not constitute a limitation on the access network device, and may include more or less components than shown, or combine some components, or arrange different components.
  • the access network device in the embodiment of the present application may be a RAN device or an AN device.
  • the execution subject of a communication method in the embodiments of the present application may be a source (or target) access network device, or a chip applied to the source (or target) access network device.
  • This embodiment of the present application does not limit this.
  • the following uses an example in which the main body of execution of a communication method is a source access network device and a target access network device.
  • an embodiment of the present application provides a communication method.
  • the method includes:
  • the source access network device sends the first data packet of the terminal to the target access network device.
  • the source access network device is an access network device that the terminal accesses before switching
  • the target access network device is an access network device that the source access network device selects for the terminal to provide services for the terminal after switching.
  • the first data packet may include a downlink data packet of the terminal processed by the source access network device during the handover process of the terminal.
  • the downlink data packet of the terminal may be a data packet received by the source access network device from the core network during the terminal handover process and sent to the terminal, or may be the source access network device to be sent to the terminal handover process
  • the data packet of the terminal may also be a data packet sent by the source access network device to the terminal during the handover of the terminal, or the source access network device may copy the data packet that needs to be sent to the terminal during the handover
  • the data packets obtained are not restricted.
  • the first data packet may include one or more (two or more) downlink data packets of the terminal.
  • the first data packet is a data packet to be sent to the terminal.
  • the source access network device may send the multiple data packets to be sent to the terminal to the target access network device in batches.
  • the first data packet may be It is the first batch of data packets sent by the source access network device to the target access network device, where the first data packet may be re-used by two or more of the multiple data packets to be sent to the terminal.
  • the encapsulated data packet ; it can also be any one of multiple data packets to be sent to the terminal.
  • the data packets to be sent to the terminal include: data packet 1 to data packet 15.
  • the first data packet may be data packet 1 to data packet 5.
  • the source access network device may be LTE eNB1 in the system shown in FIG. 1, and the target access network device may be LTE eNB2 in the system shown in FIG. 1.
  • the source access network device may be the LTE eNB in the system shown in FIG. 2 and the target access network device may be the eLTE eNB in the system shown in FIG. 2.
  • the source access network device may send the first data packet to the target access network device through the X2 interface.
  • the source access network device may be an eLTE eNB in the system shown in FIG. 2, and the target access network device may be an NR gNB in the system shown in FIG. 2.
  • the source access network device may be gNB1 in the system shown in FIG. 4, and the target access network device may be gNB2 in the system shown in FIG.
  • the source access network device may send the first data packet to the target access network device through the Xn interface.
  • Example 3 If there is no Xn / X2 interface between the source access network device and the target access network device, the source access network device may directly transmit the first data packet to the target access network device. For example, a tunnel is established between the source access network device and the target access network device. The source access network device transmits the first data packet to the target access network device through a tunnel established with the target access network device. Alternatively, the source access network device sends the first data packet to the source UPF network element corresponding to the source access network device, the source UPF network element is sent to the target UPF network element, and the target UPF network element is then forwarded to the target access network device. If the source UPF network element and the target UPF are the same UPF, the source UPF network element may directly send the first data packet to the target access network device.
  • a tunnel is established between the source access network device and the target access network device.
  • the source access network device transmits the first data packet to the target access network device through a tunnel established with the target access network device.
  • the source access network device may also be a CU or DU in gNB1 as shown in FIG. 9, and the target access network device may also be a CU or DU in gNB2 as shown in FIG. 9.
  • This embodiment of the present application does not limit this.
  • the downlink data packet of the terminal in the embodiment of the present application may be obtained from the core network corresponding to the source access network device.
  • the specific acquisition process please refer to the description in the prior art, which will not be repeated here.
  • the downstream data packet of the terminal includes: the downstream data packet of the terminal (abbreviated as: cached data packet) buffered in the buffer of the source access network device (for example, data packet 2 and data packet 3).
  • the source access network device receives the new data packet of the terminal (abbreviation: new data packet) from the UPF network element, and the duplicate data packet of the terminal (see the foregoing description).
  • the copied data packet may be a data packet obtained by copying the data packet 1.
  • the cached data packet may generally refer to a layer 2 data packet, which has encapsulated a PDCP header.
  • the new data packet is a data packet without encapsulating the PDCP header, for example, it may be an IP packet.
  • the copied data packet mainly refers to a data packet that has been sent to the terminal through the source access device, or a data packet that is ready to be sent to the terminal.
  • the source access network device After the source access network device sends a data packet to the terminal, the source access network device will not have the data packet except for the duplicate data packet of the data packet.
  • the target access network device receives the first data packet from the terminal of the source access network device.
  • the interface on which the target access network device receives the first data packet of the terminal may be combined with the network in which the source access network device and the target access network device are located, and details are not described herein again. For example, if the source access network device sends the first data packet to the target access network device on the Xn interface, the target access network device may receive the first data packet on the Xn interface.
  • the source access network device determines that the target access network device receives the first data packet, the source access network device sends the first message to the terminal.
  • the first message is used to instruct the terminal to switch to the target access network device.
  • S103 can be replaced by the following process: the source access network device determines that the target access network device receives the first data packet, and the source access network device sends the first message to the terminal.
  • S103 may be replaced by: when the source access network device receives the second message from the target access network device, the source access network device sends the first message to the terminal. Or, the source access network device determines that the target access network device receives the first data packet according to the delay information. Or, after the source access network device receives the second message from the target access network device, the source access network device sends the first message to the terminal.
  • the first message may be a handover command, and the first message carries at least identification information of the target access network device.
  • the identification information of the target access network device is used to identify the target access network device.
  • the method provided in this embodiment of the present application further includes:
  • the terminal receives the first message from the source access network device, and switches to the target access network device according to the first message.
  • the terminal can switch from the source access network device to the target access network device after receiving the first message from the source access network device.
  • the first message may carry the target cell identifier, and the terminal accesses the target cell, so as to switch to the target access network device.
  • the target cell is a cell in the target access network device.
  • the target cell identifier may be sent from the target access network device to the source access network device.
  • the first message may be a switching command.
  • the target access network device sends the first data packet to the terminal.
  • S105 may be replaced in the following manner: the target access network device determines that the terminal successfully switches from the source access network device to the target access network device, and the target access network device sends the first data packet to the terminal.
  • S105 may further include: the terminal receiving the first data packet from the target access network device.
  • the first data packet sent to the terminal in step 105 may be sent to the terminal multiple times.
  • the multiple The data packet is repackaged into at least two downlink data packets and sent to the terminal.
  • the multiple data packets can be split into the multiple downlink data packets and sent to the terminal; or they can be sent to the terminal at one time without restriction.
  • the source access network device before the source access network device sends the first message to the terminal, the source access network device needs to send the data packet that needs to be sent to the terminal during the handover process to the terminal. In this way, the terminal can obtain the data packet sent to the terminal during the handover from the source access network device before switching to the target access network device. After the terminal switches to the target access network device, the terminal can switch from the target access network device Get the data packet sent to the terminal. On the one hand, if the terminal does not receive a certain data packet from the source access network device correctly (for example, the data packet is not parsed correctly or the data packet is not successfully received due to poor air interface quality, etc.), the terminal can also A copy of the same data packet received at the target access network device.
  • the terminal may discard duplicate data packets according to the SN of the data packet, that is, reserve one data packet with the same SN, or if the terminal determines that a certain SN already exists, it may discard the newly received data packet of the SN.
  • the source access network device since the terminal switches to the target access network device (that is, before the source access network device sends the first message to the terminal), the source access network device still needs to send the first data packet Send to the terminal. If the signal quality of the air interface is poor during the handover process, the terminal may not receive the first data packet. Therefore, the source access network device sends the first data packet to the target access network device, so that when the source access network device determines that the target access network device receives the first data packet, it sends an instruction to the terminal to switch the terminal to the target The first message of the access network device. On the one hand, the first data packet can be provided at the target access network device.
  • sending the first message to the terminal may enable the target to connect to the target access network device after the terminal successfully switches from the source access network device to the target access network device.
  • the network access device sends the first data packet to the terminal. This can ensure that the terminal cannot obtain the first data packet from the source access network device during the handover process, and can also obtain the first data packet from the target access network device, ensuring the reliability of data transmission.
  • the data packet sent to the target access network device is before the handover command is sent to the terminal, this is compared with the prior art in which the data packet of the terminal is sent to the target access network device after the handover command is sent to the terminal. Can further reduce the delay.
  • the first data packet includes a duplicate data packet.
  • the foregoing method may further include: the source access network device obtains the duplicate data packet; or, When the condition for switching the access network device for the terminal is satisfied, the source access network device obtains a copy data packet.
  • the source access network device may obtain the copied data packet by using the following manner 1 or manner 2:
  • Method 1 The source access network device copies the data packet that meets the preset condition among the data packets of the terminal to obtain the copied data packet. That is, when the source access network device determines that the data packet meets the preset condition during the handover process, the source access network device copies the data packet that meets the preset condition to obtain the copied data packet.
  • the data packets of the terminal in the embodiments of the present application may refer to the downlink data packets of the terminal in step S101, and will not be described in detail.
  • the source access network device in the embodiment of the present application has preset conditions.
  • the preset condition may be pre-configured in the source access network device.
  • the preset condition may be configured by the core network device to the source access network device. This embodiment of the present application does not limit this.
  • the data packets satisfying the preset conditions include at least one of the following situations: data packets using a preset QoS flow, preset data packets on a packet data unit (PDU) session, and a packet loss rate Data packets less than or equal to the preset threshold, or data packets on the preset radio bearer.
  • PDU packet data unit
  • the data packet satisfying the preset condition further includes: a data packet using a preset service type, and a data packet whose reliability requirement is greater than or equal to a second preset threshold.
  • the second preset threshold here is used to distinguish from the preset threshold.
  • the packet loss rate is less than or equal to the preset threshold value can also be described as "the packet loss rate requirement is less than or equal to the preset threshold value”.
  • the source access network device can enable the replication function for a specific data packet to meet the QoS requirements of the service corresponding to the data packet.
  • the QoS guarantee capability of the corresponding service or data packet can be guaranteed. For example, it is possible to improve the QoS guarantee capability for the data transmission of the service of the specified terminal.
  • the preset radio bearer may also be at least one radio bearer among one or more radio bearers (RBs) possessed by the terminal.
  • the RB may be a signaling radio bearer (signalling radio bearers, SRB) or a data radio bearer (data radio bearers, DRB).
  • the source access network device copies all the data packets carried on the preset radio bearer.
  • the source access network device may determine whether the data packet is a data packet carried on a preset wireless bearer according to the identifier of the terminal carried in the data packet and the identifier of the wireless bearer of the terminal.
  • the source access network device can also be based on the tunnel endpoint identifier (TEID) of the GTP tunnel carried in the data packet (or based on the general packet radio service tunnel protocol (general packet service radio tunnel service protocol, GTP) carried in the data packet.
  • TEID tunnel endpoint identifier
  • GTP general packet radio tunnel service protocol
  • the TEID of the tunnel and the identifier of the source access network device determine whether the data packet is a data packet carried on a preset wireless bearer, or the source access network device can also be determined by the terminal ID and the TEID of the GTP tunnel Whether the data packet is a data packet carried on a preset wireless bearer.
  • the preset wireless bearer may be a wireless bearer corresponding to a service with high reliability requirements, or the preset wireless bearer may be some preset wireless bearers.
  • the preset radio bearer may be DRB1.
  • the source access network device determines that a data packet 1 is transmitted using DRB1, the source access network device copies the data packet 1.
  • PDU session a combination of a set of QoS flow flows established on the terminal within a 5G network. These QoS flows have the same IP address and Data Network Name (DNN). On the terminal and network side, an PDU session is identified by IP address and DNN.
  • DNN Data Network Name
  • Each PDU session has a unique identifier.
  • the unique identifier of the PDU session can be one of the following: PDU session identifier, APN, user plane core network device identification, user plane core network device address (for example, IP address), The IP address assigned by the user plane core network device to the terminal.
  • the preset packet data unit PDU session may also be one or more PDU sessions.
  • the source access network device copies all the data packets carried on the preset packet data unit PDU session.
  • the source access network device may determine whether the data packet is a preset group according to the TEID of the GTP tunnel carried in the data packet (or according to the TEID of the GTP tunnel carried in the data packet and the identifier of the source access network device such as an IP address) The data packet on the PDU session of the data unit.
  • the source access network device may also determine whether the data packet is a data packet on a preset packet data unit PDU session according to the terminal identifier carried in the data packet and the TEID of the GTP tunnel.
  • the TEID may be included in the GTP layer protocol header of the data packet.
  • a terminal may have multiple PDU sessions. For example, PDU session 1, PDU session 2, and PDU session 3. If the preset packet data unit PDU session is PDU session 1 and PDU session 2, the source access network device replicates all the data packets carried on PDU session 1 and PDU session 2.
  • QoS flow refers to a data flow with the same QoS requirements within a PDU session. It can be multiple IP flows with the same QoS requirements.
  • the quality of service flow identification (QoS, Flow, Identity, QFI) can be parsed in the header information of the GTP layer to obtain it, or the QFI of the QoS flow can be at the service data adaptation (Service Data Adaptation, SDAP) layer It is parsed to get it.
  • the SDAP layer represents a service adaptation layer.
  • the SDAP layer has at least one of the following capabilities: adding routing information that can be recognized by the access network device to the data packet, performing routing based on the routing information, and adding a data packet that can be The identification information related to the QoS requirements recognized by the access network device, the QoS mapping performed on the multi-segment link including the wireless backhaul node for the data packet, adding the packet type indication information to the data packet, and providing the flow control capability to the The node sends flow control feedback information.
  • the preset QoS flow may also be one or more QoS flows.
  • the source access network device copies all the data packets in the preset QoS flow.
  • the source access network device may determine whether the data packet is a preset QoS flow according to the QFI in the data packet.
  • QFI may be included in the GTP layer protocol header of the data packet.
  • the terminal determines that the data packet is a data packet of the preset QoS flow.
  • the source access network device may be determined according to the reliability requirements of the service, and the reliability of the service may include the delay, packet loss rate, and jitter of the service.
  • the source access network device can copy the data packets of services with high reliability requirements.
  • the service corresponding to the preset PDU session in case (2) is a service with high reliability requirements
  • the service corresponding to the preset QoS flow in case (3) is a service with high reliability requirements.
  • the data packet usually carries information indicating the packet loss rate.
  • the source access network device determines the information indicating the packet loss rate in the received data packet, indicating that the packet loss rate of the data packet is less than or equal to the preset threshold, then the source access network device copies the data packet .
  • the data packet is a data packet of a preset service type
  • the service of the preset service type may be a service with high reliability requirements, for example, may be an ultra-reliable low latency communication (URLLC) service.
  • the data packet may be a data packet of URLLC service.
  • the data packet may carry information indicating the service type of the data packet. If the service type indicated by the data packet is the URLLC service, the source access network device copies the data packet.
  • the data packet is a data packet whose reliability requirement is greater than or equal to the second preset threshold
  • the reliability of a data packet can be understood as the reliability of the service to which the data packet belongs.
  • the second preset threshold value may be preset or determined by the source access network device according to a preset rule.
  • the data packet satisfying the preset condition may also include the above-mentioned various situations (that is, when the data packet satisfies the conditions shown in the above-mentioned various situations, the data packet meets the preset condition), for example: the data packet satisfies (1) ( 4)
  • the data packet satisfies (1) ( 4)
  • the conditions of any one or more of the cases in (2) and (3) are also satisfied.
  • Method 2 The source access network device copies the data packet of the terminal to obtain a copy data packet.
  • the above method 2 is an implementation method with the terminal as the granularity.
  • the source access network device copies the data packets of the terminal.
  • the source access network device may identify the data packet of the terminal according to the identifier of the terminal carried in the data packet, and copy the identified data packet.
  • the core network device may instruct the source access network device to copy all data packets of the terminal during the handover process. Specifically, the core network device may instruct the source access network device to copy data packets of a specific type of terminal during the handover process.
  • the above mainly describes the granularity of the data packet copied by the source access network device.
  • the source access network device can select the granularity of the copied data packet according to need.
  • the source access network device may determine the granularity of the copied data packet according to the QoS requirements of the service or according to the default radio bearer information of the session or according to the instructions of the core network. For example, if the core network instructs to copy data packets at the terminal granularity, the source access network device copies all data packets of the terminal to obtain copied data packets. For example, if the QoS flow of the service meets specific QoS requirements, the source access network device determines the QoS flow as the preset QoS flow. Then all the data packets on the preset QoS flow are copied to obtain copied data packets.
  • the source access network device when it determines the data packet that satisfies the preset condition, it can copy the data packet that satisfies the preset condition in a unified manner.
  • the data packets satisfying the preset condition include: data packet 1, data packet 2, then the source access network device copies data packet 1, and copy data packet 2.
  • the source access network device may copy each data packet that meets the preset condition when it determines that a data packet that satisfies the preset condition is sent. For example, when the source access network device sends data packet 1, data packet 1 is copied. When the source access network device sends the data packet 2, the data packet 2 is copied.
  • the copied data packet may be cached in the source access network device before being sent to the target access network device.
  • the data packet of the terminal may include a duplicate data packet that duplicates the data packet received from the core network.
  • the duplicate data packet does not include the sequence number (SN); it may also include the source access network.
  • the data packet sent by the device to the terminal is a copy data packet for copying. At this time, the copy data packet includes the SN.
  • the source access network device may determine the target in the following manner The access network device receives the first data packet.
  • the above method may further include:
  • the target access network device sends a second message to the source access network device, where the second message is used to indicate that the target access network device receives the first data packet.
  • the source access network device may receive the second message from the target access network device, and then execute the source access network device in step S103 to send the first message to the terminal.
  • the second message may be a data reception determination instruction (for example, User Data received indication).
  • the source access network device determining that the target access network device receives the first data packet may be specifically implemented in the following manner: the source access network device may determine the target access network device according to the second message The first data packet is received.
  • step S103 may be replaced by: when the source access network device receives the second message from the target access network device, the source access network device sends the first message to the terminal.
  • the source access network device determines that the target access network device receives the data packet, and can also be implemented in the following manner 3:
  • step S103 may be replaced by: when the source access network device determines that the target access network device receives the first data packet according to the delay information, the source access network device sends the first message to the terminal.
  • the source access network device may start a timer when sending the first data packet to the target access network device, and if the timer times out, it is determined that the target access network device receives the first data packet.
  • the embodiment of the present application does not limit the manner of acquiring delay information.
  • the delay information may be pre-configured for the terminal, or the source access network device may determine the delay information according to the QoS information of the first data packet, or the source access network device during the session management process Obtain delay information from the session management functional unit.
  • the source access network device may determine the transmission delay of the core network according to the 5G QoS identification (5QI) information in the QoS parameters, thereby determining the delay information.
  • 5QI 5G QoS identification
  • the session management process may refer to a PDU session establishment process or a PDU session update (also called PDU session modification) process.
  • the source access network device may send the terminal's data packet to the target access network device, that is, the source access network, when it is determined to switch the terminal to the target access network device
  • the device may send the data packet of the terminal to the target access network device during the process of sending the handover request message to the target access network device. In this case, if the target access network device allows the terminal to be switched to the target access network device, the delay can be reduced.
  • the source access network device when the source access network device determines that the target access network device allows the terminal to be switched to the target access network device, the source access network device sends the terminal's data packet to the target access device Network access equipment. In this way, it is convenient to send a data packet to the target access network device to the terminal only when the target access network device allows handover. Avoid wasting resources when the target access network device refuses to switch.
  • the above method may further include:
  • the target access network device sends first information to the source access network device, where the first information is used to indicate that the terminal is allowed to switch to the target access network device.
  • the first information may be carried in a handover request confirmation message, or the first information is a handover request confirmation message.
  • the source access network device receives the first information from the target access network device.
  • the source access network device after the source access network device sends a handover request message to the target access network device, the source access network device receives first information from the target access network device to indicate that handover is allowed, the source access The network device sends the first data packet to the target access network device.
  • S101 may also be replaced by the following steps: the source access network device determines that the target access network device allows the terminal to switch to the target access network device according to the first information , The source access network device sends the first data packet to the target access network device.
  • the source access network device obtains the measurement report and radio resource management information.
  • the source access network device determines that the condition for switching the access network device for the terminal is met according to the measurement report and the radio resource management information, then the source access network device enables the packet copy function, that is, the source access network device activates the source access network device
  • the data copy function can also be understood as the source access network device performing the above steps of copying the data packet.
  • the measurement report may be reported by the terminal to the source access network device.
  • the source access network device determines that the signal quality or level of the source access network device is lower than a preset threshold according to the measurement report, and determines that the condition for switching the access network device for the terminal is satisfied.
  • the source access network device may send a handover request message to the target access network device, where the handover request message is used to request the terminal to be handed over to the target access network device. If the target access network device allows the terminal to be handed over to the target access network device, the target access network device sends a message to the source access network device indicating that the handover is agreed (ie, the first information above), so that the source access network device It can be determined that the target access network device allows the terminal to be switched to the target access network device.
  • the handover request message may include a cell-radio network temporary identification (C-RNTI) of the source access network device, a target cell identification, a physical layer identification of the source cell, and key parameters.
  • C-RNTI cell-radio network temporary identification
  • the handover request message may include a cell-radio network temporary identification (C-RNTI) of the source access network device, a target cell identification, a physical layer identification of the source cell, and key parameters.
  • C-RNTI cell-radio network temporary identification
  • the source access network device may send a handover request message to the target access network device through the Xn interface or X2 interface.
  • the target access network device may also send a message indicating that the handover is approved to the source access network device through the X2 interface or the Xn interface.
  • the source access network device and the target access network device may exchange a handover request message and a message indicating that the handover is approved through the X2 interface.
  • the source access network device and the target access network device may exchange a handover request message and a message indicating that the handover is approved through the Xn interface.
  • the source access network device may send a handover request message to the mobile management network element 1 corresponding to the source access network device, and then The handover request message is sent to the mobile management network element 2 corresponding to the target access network device through the mobile management network element 1. Then, the mobile management network element 2 sends the handover request message to the target access network device. When the target access network device agrees to the handover, the target access network device sends the message indicating the approval of the handover to the source access network device through the mobile management network element 2 and the mobile management network element 1.
  • the mobility management network element eg, AMF network element or MME
  • mobility management network element 2 may be the same mobility management network element.
  • LTE eNB1 sends the handover request message to EPC
  • EPC sends the handover request message to LTE eNB2 through the S1 interface.
  • LTE eNB2 sends a message indicating the consent to handover to the EPC through the S1 interface
  • the EPC sends a message indicating the consent to handover to the LTE eNB1 through the S1 interface.
  • gNB1 taking the source access network device as gNB1 and the target access network device as gNB2 as an example, if there is no Xn interface between gNB1 and gNB2, gNB1 will switch the request message It is sent to NG-Core through the N2 interface, and then NG-Core sends the handover request message to gNB2 through the N2 interface. Conversely, when gNB2 agrees to the handover, gNB2 sends the message indicating the consent to handover to NG-Core through the N2 interface, and NG-Core sends the message indicating the consent to handover to gNB1 through the N2 interface.
  • the source access network device and the target access network device belong to different networks and there is no interface between the source access network device and the target access network device
  • the source access network device is the eNB
  • the target access For example, if the network device is gNB, the eNB sends the handover request message to the EPC through the S1 interface, and then the EPC sends the handover request message to the NG-Core through the interface with the NG-Core, and then the NG-Core is sent to gNB.
  • gNB2 when gNB2 agrees to the handover, gNB2 sends the message indicating the consent to handover to the NG-Core through the N2 interface, and NG-Core sends the message indicating the consent to handover to the EPC through the interface.
  • the EPC sends a message indicating that the handover is approved to the LTE eNB1 through the S1 interface.
  • the interface for the source access network device to send the data packet to the target access network device may refer to the interface for the source access network device to send the handover request message to the target access network device.
  • the source access network device may also send the serial number SN status to the target access network device during the process of sending the terminal's data packet to the target access network device information.
  • the above method may further include:
  • the source access network device sends the serial number SN status information to the target access network device.
  • the SN status information is used by the target access network device to send data packets to the terminal.
  • the SN status information may specifically include: downlink PDCPSN sending status.
  • the downlink PDCP SN sending status is used to indicate the next new PDCP SN number that the target access network device needs to allocate.
  • the SN status information may be sent to the target access network device during the process that the source access network device requests the target access network device for handover.
  • the SN status information can be carried in the handover request message.
  • the target access network device after receiving the first data packet, the target access network device can set the SN of the data packet according to the SN status information.
  • the source access network device sends the SN status information to the target access network device, which may be caused by the following situations.
  • the SN status information is used to indicate the SN of the data packet sent by the source access network device to the terminal.
  • the other case is used to instruct the target access network device to send the SN that the terminal should carry.
  • the target access network device receives SN status information from the source access network device.
  • the above method may further include S111:
  • the target access network device processes the data packet that does not carry the SN received from the source access network device according to the SN status information, obtains a second data packet, and sends the second data packet to the terminal.
  • the SN of the second data packet can be determined according to the SN status information.
  • the data packet that does not carry the SN may be a data packet in the first data packet, such as an IP packet, or an Ethernet packet, or other types of data packets.
  • the first data packet includes: data packet 1, data packet 2, and data packet 3, where the source access network device has set the SN for data packet 1 and data packet 2, that is, data packet 1 and data packet 2 carry the SN. Whereas the data packet 3 does not carry the SN, when the target access network device receives the data packet 3, it can determine the SN of the data packet 3 according to the SN status information.
  • the data packet not carrying the SN may also be a data packet other than the first data packet among the data packets of the terminal.
  • the data packet of the terminal includes a first data packet and a second data packet, where the first data packet carries the SN and the second data packet does not carry the SN, and the SN of the second data packet is determined according to the SN status information.
  • S111 may further include: the terminal receiving the second data packet sent by the target access network device.
  • FIG. 16 shows another communication method provided by an embodiment of the present application.
  • the source access network device is the S-RAN device and the target access network device is the T-RAN device.
  • the Xn interface between the S-RAN device and the T-RAN device is used as an example for description, as follows.
  • Step 201 The S-RAN device obtains the terminal context from the AMF network element.
  • the S-RAN device obtains mobility control information (Mobility Control Information) from the AMF network element.
  • Mobility Control Information Mobility Control Information
  • the mobile control information may include terminal context.
  • the terminal context may include roaming access restriction information.
  • the access restriction information may be provided during connection establishment or tracking area (Tracking Area, TA) update, and the access restriction information may include available frequency band information.
  • TA Tracking Area
  • the terminal may establish a connection with the core network through the S-RAN device, and data may be transmitted between the terminal and the core network through the established connection. For example, the terminal sends the uplink data packet to the core network through the S-RAN device, or the terminal receives the downlink data packet sent by the core network through the S-RAN device.
  • Step 202 The S-RAN device configures measurement configuration parameters for the terminal.
  • the S-RAN device may be 5G gNB, NR, or other RAN devices, which is not limited in this embodiment of the present application.
  • Step 203 The terminal sends a measurement report (Measurement Reports) to the S-RAN device according to the measurement configuration parameter.
  • the measurement report is used to indicate the signal quality measured by the terminal, and may include measurement reports of one or more RAN devices.
  • the S-RAN device is the RAN device to which the serving cell of the terminal belongs.
  • the terminal periodically measures the signal quality of the terminal's serving cell and the signal quality of the terminal's neighboring cells.
  • the terminal may periodically send a measurement report to the S-RAN device.
  • the measurement report includes: the signal quality of the RAN device to which the serving cell belongs and the signal quality of the RAN to which the terminal's neighboring cell belongs.
  • the event report may also be triggered to send a measurement report to the S-RAN device, or after the TA to which the terminal belongs changes, the measurement report may be sent to the S-RAN device.
  • the S-RAN device determines whether to switch the RAN device for the terminal according to the measurement report reported by the terminal.
  • the first network in the embodiment of the present application is an EPC network or an NG-Core network.
  • the signal quality may include reference signal received power (Reference Signal Receiving Power, RSRP).
  • the signal quality may include reference signal reception quality (Reference Signal Receiving Quality, RSRQ).
  • the signal quality may include RSRP and RSRQ.
  • any parameters that can be used to reflect the signal quality of the RAN device to which the terminal receives the serving cell and the signal quality of the RAN to which the terminal's neighbor cell belongs can be used as the signal quality of the RAN device to which the terminal receives the serving cell and the neighbor of the terminal
  • the signal quality of the RAN to which the cell belongs is not limited in this embodiment of the present application.
  • the terminal when the terminal determines that the signal quality of the serving cell is less than or equal to the first preset threshold, or the signal quality of the neighboring cell is greater than or equal to the second preset threshold, the terminal sends a measurement report to the S-RAN device.
  • the terminal sends the acquired signal quality of the serving cell or the signal quality of the neighboring cell as a measurement report to the S-RAN device at a preset period according to a preset period.
  • the terminal may receive a measurement indication sent by the S-RAN device, where the measurement indication is used to instruct the terminal to measure the signal quality of the serving cell or the signal quality of the neighboring cell.
  • the terminal can measure the signal quality of the serving cell or the signal quality of the neighboring cell according to the measurement configuration parameter.
  • the measurement indication may also be used to instruct the terminal to periodically send a measurement report to the S-RAN device according to a preset period, and the signal quality in the serving cell is less than or equal to the first preset threshold, or the neighboring cell ’s When the signal quality is greater than or equal to the second preset threshold, the terminal sends a measurement report to the S-RAN device.
  • the first preset threshold, the second preset threshold, and the preset period are not limited, and can be set according to requirements.
  • Step 204 The S-RAN device determines to perform handover (Handover Decision) based on the measurement report and Radio Resource Management (RRM) information, and activates (or enables) the data packet replication function.
  • RRM Radio Resource Management
  • the data packet copy function may refer to the S-RAN device copying the data packet that the S-RAN device needs to send to the terminal during the handover process.
  • the activation of the data packet copy function is an optional action and may not be executed.
  • the S-RAN device may determine that the RAN device needs to be switched for the terminal, but the terminal does not access the T-RAN device at this time.
  • the S-RAN device needs to send the data packet sent to the terminal to the terminal.
  • the period before the S-RAN device determines that it needs to switch the RAN device for the terminal to the time that the S-RAN device sends the handover command to the terminal is defined as the handover process, and the S-RAN device needs to send the data packet to the terminal during the handover process as the first One packet.
  • the S-RAN device may copy the first data packet to obtain the copied data packet. It should be understood that the first data packet and the duplicate data packet are the same data packet.
  • the S-RAN device determines to initiate a handover, it needs to send data packet 1 and data packet 2 to the terminal, then the S-RAN device can copy data packet 1 to obtain data packet 1 ', and copy data packet 2 to obtain data Pack 2 '. Then send data packet 1 and data packet 2 to the terminal.
  • the RRM information includes information about the RAN to which one or more neighboring cells belong.
  • the S-RAN device determines that the signal quality of the serving cell does not meet the needs according to the measurement report, it determines a RAN device as the radio resource management information.
  • the S-RAN device may select, according to the signal quality of one or more neighboring cells, a RAN device to which the neighboring cell whose signal quality is greater than or equal to the second preset threshold belongs as the T-RAN device for terminal switching.
  • Step 205 The S-RAN device sends a handover request message (Handover Request message) to the T-RAN device.
  • the handover request message can be used to request the terminal to be handed over to the T-RAN device.
  • the handover request message includes but is not limited to the following information: handover reason, used to indicate the cause of this handover, for example, the wireless network layer reason (handover triggered by signal reason, resource-based optimization, etc.).
  • the target cell ID is used to uniquely indicate the target cell ID. List of handover restrictions, including serving PLMN, equivalent PLMN, prohibited service area, etc.
  • the temporary identifier corresponding to the terminal is used by the CN device to search for the saved terminal context (UE context).
  • the network slice identifier corresponding to one or more or all network slices selected by the terminal respectively.
  • the wireless bearer information to be established corresponding to one or more or all network slices selected by the terminal such as a wireless bearer identifier, a QoS parameter of a wireless bearer level, a tunnel termination point, and user plane security information corresponding to the wireless bearer.
  • One or more or all network slices selected by the terminal correspond to session information to be established, such as session identifier, session-level QoS parameters, tunnel termination point, and user plane security information corresponding to the session.
  • the one or more or all network slices selected by the terminal correspond to the flow information to be established, such as flow identification, flow-level QoS parameters, tunnel termination point, and user plane security information corresponding to the flow.
  • Wireless bearer information such as wireless bearer identification, QoS parameters of wireless bearer level, tunnel end point, and user plane security information corresponding to the wireless bearer.
  • Other session information that needs to be established such as session identification, session-level QoS parameters, tunnel endpoints, and user plane security information corresponding to the session.
  • Other flow information that needs to be established such as flow identification, flow-level QoS parameters, tunnel end point, and user plane security information corresponding to the flow.
  • the context information of the terminal device for example, the network slice identifier corresponding to one or more or all network slices subscribed by the terminal device.
  • the UE context includes a Mobility Management Context (MM) Context and a Bearer Context (Bearer Context), and network slicing indication information, where the MM Context includes a temporary identifier GUTI, Non-Access Stratum , NAS) key, security algorithm and other information, Bearer Context includes bearer identification, QoS and other information.
  • MM Context Mobility Management Context
  • Bearer Context Bearer Context
  • network slicing indication information where the MM Context includes a temporary identifier GUTI, Non-Access Stratum , NAS) key, security algorithm and other information
  • Bearer Context includes bearer identification, QoS and other information.
  • the Handover Request message includes downlink SN status (DL SN Status) information.
  • DL SN Status downlink SN status
  • the S-RAN device sends a handover request (Handover Required) message to the T-RAN device through an interface (such as the Xn interface) with the T-RAN device.
  • a handover request such as the Xn interface
  • Step 206 The T-RAN device performs admission control (Admission Control).
  • the T-RAN device indicates to the admission control that the T-RAN device has prepared resources and is ready for handover.
  • the T-RAN device performs admission control on the terminal according to its own support capabilities, resource conditions, and remapping policy information for the network slice flow / session / radio bearer that the terminal communicates with the S-RAN device. .
  • the T-RAN device determines that the terminal can support the flow / session / radio bearer of the network slice communicated by the S-RAN device, resource conditions, and remapping policy information, the T-RAN device performs admission Control (Admission), otherwise the T-RAN device sends an instruction message to the S-RAN device to refuse to switch the terminal to the T-RAN device. For example, if the T-RAN device determines that the radio resource requirements required by the terminal can be met, the T-RAN device performs admission control on the terminal.
  • Admission Control Admission Control
  • the T-RAN device does not support at least one stream / session / radio bearer of the at least one network slice communicated by the terminal in the S-RAN device but has the capability of the relevant network slice support, then the T-RAN device The device may request the CN to remap at least one stream / session / radio bearer of at least one network slice communicated by the terminal on the S-RAN device to a network slice supported by the T-RAN device.
  • the T-RAN device determines that the T-RAN device does not support at least one network slice that the terminal communicates with the S-RAN device through the network slicing indication information carried in the handover request message received in step 205.
  • the received radio bearer context and the current resource usage status, etc. determine that the QoS requirements of the terminal's current communication flow / session / radio bearer can be met, and the T-RAN device considers that the terminal's flow / session / radio bearer is required. Support for network slicing.
  • the T-RAN device cannot clearly determine whether the terminal supports network slices communicated by the S-RAN device, then the T-RAN device may request from the CN that the terminal is not supported by the T-RAN device In the case of at least one network slice communicated by the S-RAN device, at least one stream / session / radio bearer of the at least one network slice communicated by the terminal in the S-RAN device is remapped to the one supported by the T-RAN device Network slice. For example, the T-RAN device cannot determine whether it can support at least one network slice communicated by the terminal in the S-RAN device through the network slice indication information carried in the handover request message received in step 205, but through the wireless received in step 205. If the bearer context and the current resource usage status determine that the terminal can meet the QoS requirements of the current communication flow / session / radio bearer, the T-RAN device considers that it has the relevant network slice support capability.
  • the T-RAN device does not support at least one stream / session / radio bearer of at least one network slice communicated by the terminal in the S-RAN device, but the T-RAN device
  • the network slice remapping policy information can remap the stream / session / radio bearer to the network slice supported by the T-RAN device, and then the T-RAN device can request the CN for the terminal to communicate with the S-RAN device.
  • At least one stream / session / radio bearer of at least one network slice is remapped to the supported network slice selected by the T-RAN device.
  • Step 207 The T-RAN device sends a handover request confirmation message (Handover Request Acknowledge message) to the S-RAN device.
  • the handover request confirmation message may be used to instruct the T-RAN device to allow the terminal to be handed over to the T-RAN device.
  • the handover request confirmation message may be the first information in the foregoing embodiment.
  • the T-RAN device may perform step 207 when performing admission control.
  • Step 208 Upon receiving the handover request confirmation message sent by the T-RAN device, the S-RAN device starts to send user plane data to the T-RAN device.
  • the user plane data includes at least a copy data packet, so that the T-RAN device can receive the user plane data from the terminal of the S-RAN device.
  • the user plane data in step 208 may be the first data packet in the foregoing embodiment.
  • the user plane data sent by the S-RAN device to the T-RAN device in 208 also includes data packets buffered in the buffer of the S-RAN device and needs to be sent to the terminal, or newly received data that needs to be sent to the terminal package.
  • the data packet buffered in the buffer of the S-RAN device needs to be sent to the terminal is data packet 21, and the data packet newly received from the air interface that needs to be sent to the terminal is data packet 22, and needs to be sent to the terminal during the handover process
  • the data packet is data packet 1 and data packet 2
  • the user plane data that the S-RAN device can send to the T-RAN device in step 208 includes: data packet 21, data packet 22, data packet 1 ', and data packet 2' .
  • the S-RAN device when the S-RAN device receives the handover request confirmation message, the S-RAN device not only sends user plane data to the terminal, but also sends user plane data to the T-RAN device.
  • the T-RAN device when the T-RAN device receives the user plane data of the terminal, the T-RAN device sends a data reception determination instruction to the S-RAN device, so that the S-RAN device receives data from the T-RAN device.
  • the data reception determination instruction of the RAN device thereby determining that the T-RAN device has received user plane data.
  • Step 209 When the S-RAN device determines that the T-RAN device receives user plane data, the S-RAN device sends a handover command to the terminal.
  • the handover command is used to instruct the terminal to switch to the T-RAN device.
  • the handover command may carry the identification of the target cell or the identification of the T-RAN device to which the target cell belongs.
  • the switching command may be the first message in the foregoing embodiment.
  • Step 210 The terminal accesses the T-RAN device according to the handover command.
  • step 210 For the specific implementation of step 210, reference may be made to the description in the prior art, and details are not described herein again.
  • Step 211 The T-RAN device sends user plane data to the terminal.
  • the user plane data may include duplicate data packets.
  • the user plane data in step 211 may refer to the first data packet in the foregoing embodiment, and details are not described herein again.
  • the data packet sent by the T-RAN device to the terminal in step 211 includes the duplicated data packet, and the processed buffered data packet that needs to be sent to the terminal in the buffer of the S-RAN device, and the processed new received from the air interface The data packet that needs to be sent to the terminal.
  • the T-RAN device can send user plane data to the terminal.
  • the terminal can also be sent through the T-RAN device To the UPF network element. Since the network side does not know that the terminal switches to the T-RAN device at this time, in order to enable the downlink data packets sent by the network side to be sent to the terminal through the T-RAN device of the terminal access network, the method provided in the embodiments of the present application may also It includes the following steps:
  • Step 212 The T-RAN device sends a path switch request (path switch Request) to the AMF network element.
  • Step 213 Perform a path switching process between the AMF network element and the core network.
  • the UPF network element can determine to send the downlink data packet of the terminal to the T-RAN device.
  • Step 214 The AMF network element sends a path switching request confirmation message to the T-RAN device.
  • the AMF network element can confirm that the RAN device serving the terminal is a T-RAN device, that is, the AMF network element can subsequently communicate with the terminal through the T-RAN device.
  • Step 215 After receiving the path switching request confirmation message, the T-RAN device sends a terminal context release (UE context release) message to the S-RAN device.
  • UE context release terminal context release
  • the S-RAN device releases the terminal's context.
  • the S-RAN device before switching the terminal to the T-RAN device, the S-RAN device sends the user plane data of the terminal to the T-RAN device, and then the S-RAN device still sends the terminal to the terminal during the handover process. Send the user plane data of the terminal.
  • the T-RAN device After the terminal successfully switches from the S-RAN device to the T-RAN device, the T-RAN device sends the user plane data of the terminal to the terminal. That is, during the handover process, the terminal can obtain two identical pieces of user plane data from the S-RAN device and the T-RAN device, respectively, thereby ensuring the reliability of data packet transmission during the handover process.
  • the S-RAN device sends the user plane data of the terminal to the T-RAN device to reduce the transmission delay of the handover.
  • Figure 16 takes the T-RAN device and the S-RAN device belonging to the same AMF network element as an example.
  • the S-RAN device and the T-RAN device may belong to different AMF network elements.
  • Figure 16 includes: handover preparation phase (Handover Preparation) (eg, steps 201-step 207), handover execution phase (Handover Execution) (eg, steps 208-step 211), and handover completion phase (Handover Completion) ( For example, steps 212-step 215).
  • handover preparation phase Handover Preparation
  • handover execution phase Handover Execution
  • handover completion phase Handover Completion
  • FIG. 17 shows a communication method provided by an embodiment of the present application.
  • the source access network device is an S-RAN device
  • the target access network device is a T-RAN device. It is assumed that the S-RAN device and the T-RAN device do not have an Xn interface.
  • the S-AMF initiates a handover process (which may be called N2 handover process) as an example.
  • the handover process of N2 mainly includes handover preparation phase and handover execution phase.
  • the N2-based handover process includes scenarios where the AMF network elements of the S-RAN device and the T-RAN device are the same, and the AMF network elements of the S-RAN device and the T-RAN device are different.
  • FIG. 1 The following FIG.
  • the S-RAN device corresponds to the S-AMF network element
  • the T-RAN device corresponds to the T-AMF network element
  • Step 301 The S-RAN device determines to initiate the N2 handover process, and copies the data packet of the terminal during the handover process.
  • the terminal establishes a connection (eg, a PDU session) with the source user plane (S-UPF) network element through the S-RAN device.
  • the terminal may send uplink (UL) user plane data to the S-UPF network element through the S-RAN device.
  • the S-UPF network element may send downlink (Downlink, DL) user plane data to the terminal through the S-RAN device.
  • step 301 For the process of the S-RAN device copying the data packet that the S-RAN device needs to send to the terminal during the handover process in step 301, reference may be made to step 204 above, which will not be repeated here.
  • Step 302 The S-RAN device sends a handover request message to the S-AMF network element.
  • the handover request message may include an identifier of the T-RAN device, a source to target container (target to source transparent), a session management (SM) N2 information list, a PDU session identifier, and an internal system handover indication.
  • a source to target container target to source transparent
  • SM session management
  • the SM N2 information list includes an indication of whether the direct forwarding path is available.
  • the system internal switching instruction is used to indicate that the switching is a 5G internal switching.
  • the direct forwarding path may refer to a path between the S-RAN device and the T-RAN device, that is, a network element that passes between the S-RAN device and the T-RAN device.
  • the source-to-target container includes RAN information used by the T-RAN.
  • the information carried in the source-to-target container is not perceptible by the core network, that is, transparent to core network nodes.
  • target to source refers to a container sent by the S-RAN device to the T-RAN device.
  • the specific content in the container is not identified and processed in the middle network element, and can be directly transmitted to the T-RAN device.
  • T-RAN device can parse the content after receiving the source to the target container.
  • the source-to-target container includes SN status information
  • the T-RAN device may set the SN of the data packet according to the SN status information.
  • the S-AMF network element is an AMF network element connected to the S-RAN device.
  • Step 303 If the S-AMF network element cannot serve the terminal, the S-AMF network element selects a T-AMF network element for the terminal.
  • the S-AMF network element selects the AMF network element connected to the T-RAN device as the T-AMF network element according to the identifier of the T-RAN device.
  • the identification of the T-RAN device is used to identify the T-RAN device.
  • the S-AMF network element determines that the T-RAN device is not managed by the S-AMF network element according to the identifier of the T-RAN device, the S-AMF network element determines that it cannot serve the terminal.
  • Step 304 The S-AMF network element sends a request to establish a terminal context connection (Namf_Communication_CreatUEContextRequest) message to the T-AMF network element.
  • the Namf_Communication_CreatUEContextRequest message includes N2 information and terminal context information.
  • the N2 information includes the identification of the T-RAN device, including the source-to-target container of the SN state, SM N2 information list, PDU session identification, one or more of the service area restrictions.
  • a PDU session corresponds to an SM N2 information list, and the SM N2 information list is sent to the SMF network element.
  • the terminal context includes a permanent identity (subscriber permanent identifier, SUPI), an allowed network slice selection auxiliary information (NSSAI) corresponding to the access type, a PDU session identifier, and the corresponding SMF network of the terminal Meta information and single network slice selection auxiliary information (Single network selection selection assistant (S-NSSAI)), PCF network element identification and data network name (data network name, DNN).
  • SUPI subscriber permanent identifier
  • NSSAI allowed network slice selection auxiliary information
  • S-NSSAI single network slice selection auxiliary information
  • PCF network element identification and data network name data network name, DNN
  • Step 305 The T-AMF network element sends a request to update the PDU session context (Nsmf_PDUSession_UpdateSMContext) Request message to the SMF network element.
  • the Nsmf_PDUSession_UpdateSMContext Request message may include a list of SM2 N2 information.
  • the PDU session context includes the IP address, access point name (APN), SMF network element and UPF network element address used in the PDU session, and context information of each QoS flow.
  • the T-AMF network element may further include determining the SMF network element in step S305 according to the SMF information carried in the terminal context.
  • Step 306 Based on the identifier of the T-RAN device, the SMF network element determines whether to allow N2 handover.
  • N2 handover is not allowed. For example, some services can only be accessed in specific areas, such as the campus network, and cannot be accessed after leaving the campus.
  • the SMF network element can detect whether the UPF network element can provide services for the terminal. For example, if the SMF network element determines that the terminal moves out of the service area of the S-UPF network element, the SMF network element selects a T-UPF network element for the terminal. If the SMF network element selects a T-UPF network element, step 307 is performed.
  • Step 307 The SMF network element sends an N4 session establishment request (Session establishment request) to the T-UPF network element, so that the T-UPF network element can receive the N4 session establishment request.
  • N4 session establishment request Session establishment request
  • the N4 session establishment request may be used to establish a user plane connection, and the N4 session establishment request may carry user plane tunnel information.
  • the T-UPF network element may also send an N4 session establishment response to the SMF network element.
  • Step 308 The SMF network element sends a PDU session context update response (Nsmf_PDUSession_UpdateSMContext Response) message to the T-AMF network element.
  • Nsmf_PDUSession_UpdateSMContext Response PDU session context update response
  • the Nsmf_PDUSession_UpdateSMContext Response message includes the N3IP address and uplink (UL) CN tunnel ID and QoS parameters. If the SMF network element does not accept PDU session switching, the Nsmf_PDUSession_UpdateSMContext Response message includes a reason value for not accepting.
  • Step 309 The T-AMF network element receives the Nsmf_PDUSession_UpdateSMContext Response message from the SMF network element.
  • step 310 is performed.
  • the T-AMF network element when the T-AMF network element receives the Nsmf_PDUSession_UpdateSMContext Response message sent by the SMF network element, if the Nsmf_PDUSession_UpdateSMContext Response message indicates that the PDU session switching is accepted, the T-AMF network element determines to perform the N2 switching process. Or the T-AMF network element determines that the maximum waiting time expires, and the T-AMF network element determines to execute the N2 handover procedure.
  • Step 310 The T-AMF network element sends a handover request message to the T-RAN device.
  • the handover request message may include at least one of N2 MM information, N2 Session Management (SM) information list, source to target container, service area limitation, or unacceptable PDU session list, where source to target The container includes SN status information.
  • N2 MM information N2 Session Management (SM) information list
  • source to target container SM
  • service area limitation service area limitation
  • unacceptable PDU session list where source to target The container includes SN status information.
  • N2 MM information contains security context and so on.
  • the list of unacceptable PDU sessions carries the identifier of the PDU session in which the handover fails.
  • Step 311 The T-RAN device sends a handover request confirmation message to the T-AMF network element.
  • the handover request confirmation message may include at least one of the target-to-source container, the N2 SM response list, the failed PDU session list, or the T-RAN SM3 N3 transmission information list.
  • the target-to-source container carries QoS flow information of the successful handover.
  • the handover request confirmation message in step 311 is the first information in the foregoing embodiment.
  • the target-to-source container refers to a container sent by the T-RAN device to the S-RAN device.
  • the specific content in the container is not identified and processed in the middle network element, and can be directly transmitted to the S-RAN device
  • the RAN device can parse the content after receiving the target-to-source container.
  • the target-to-source container may include a security context, QoS information, and target cell identification.
  • Step 312 The T-AMF network element sends an Nsmf_PDUSession_UpdateSMContext Request message to the SMF network element. In this way, the SMF network element receives the Nsmf_PDUSession_UpdateSMContext Request message from the T-AMF network element.
  • the Nsmf_PDUSession_UpdateSMContext Request message includes the PDU session ID, N2 SM response, and T-RAN SM3 N3 forwarding information list.
  • the T-AMF network element For each N2 SM response, the T-AMF network element sends an N2 SM response to the SMF network element; if there is no T-UPF network element, the SMF network element stores N3 tunnel information.
  • the N3 tunnel information includes a tunnel identifier and a tunnel address.
  • the SMF network element selects the T-UPF network element when performing step 306, the SMF network element performs step 313.
  • Step 313 The SMF network element sends an N4 session modification request (N4 session modify request) to the T-UPF network element.
  • the N4 session modification request includes a T-RAN SM3 N3 forwarding information list, and an instruction to optionally allocate a DL forwarding tunnel.
  • the T-RAN SM3 N3 forwarding information list includes the N3 address and the N3 tunnel ID.
  • Step 314 The N4 session modify response (N4 session modify response) message sent by the UPF network element to the SMF network element.
  • the N4 session modification response message may include a list of SM N3 forwarding information.
  • Step 315 The SMF network element sends an N4 session modification request to the S-UPF network element.
  • the N4 session modification request may include a T-RAN SM3 N3 forwarding information list or a T-UPF SMN3 forwarding information list, and an indirect forwarding DL forwarding tunnel indication.
  • Step 316 The S-UPF network element sends an N4 session modification response to the SMF network element.
  • the N4 session modification response includes the S-UPF SM3 N3 forwarding information list.
  • Step 317 The SMF network element sends the Nsmf_PDUSession_UpdateSMContext Response including the N2 SM information list to the T-AMF network element.
  • Step 318 The T-AMF network element sends Namf_Communication_CreateUEContext Response to the S-AMF network element.
  • the response may include at least one of N2 information, PDU session establishment failure list, or N2 SM information list.
  • Step 319 The S-AMF network element sends a handover command to the S-RAN device.
  • the handover command includes the container from the target to the source, and / or N2 SM information.
  • the handover command may also include a list of failed PDU sessions.
  • Step 320 When the S-RAN device receives the handover request confirmation message sent by the T-RAN device, the S-RAN device starts sending the terminal's data packet to the T-RAN device.
  • the data packet of the terminal may include a copy data packet.
  • the handover request confirmation message may be the first information in the foregoing embodiment.
  • the T-RAN device may also send a data reception determination indication (for example, the second message in the foregoing embodiment) to the S-RAN device.
  • a data reception determination indication for example, the second message in the foregoing embodiment
  • Step 321 When the S-RAN device determines that the T-RAN device receives the data packet of the terminal, the S-RAN device sends a handover command (Handover Command) to the terminal.
  • a handover command Handover Command
  • the switching command may include the container of the terminal.
  • the switching command in step 321 is the first message in the foregoing embodiment.
  • the container of the terminal includes the identity of the target cell.
  • Step 322 The terminal synchronizes to the target cell according to the handover command.
  • Step 323 The T-RAN device sends a handover confirmation message to the terminal.
  • the handover confirmation message can be used to indicate that the handover is successful.
  • the T-RAN device may send the data packet of the terminal obtained from the S-RAN device to the terminal.
  • Step 324 The T-RAN device sends a handover notification to the T-AMF network element.
  • the handover notification can be used to indicate a successful handover.
  • Step 325 The T-AMF network element sends an N2 communication information notification (Namf_Communication_N2InfoNotify) to the S-AMF network element.
  • Namf_Communication_N2InfoNotify N2 communication information notification
  • Step 326 The S-AMF network element sends Namf_Communication_N2InfoNotify to the T-AMF network element.
  • Step 327 The S-AMF network element sends a (Nsmf_PDUSession_ReleaseSMContext) request to release the PDU session context to the SMF network element.
  • the Nsmf_PDUSession_ReleaseSMContext request may include SUPI and PDU session identifiers.
  • Step 328 The T-AMF network element sends an Nsmf_PDUSession_UpdateSMContext request to the SMF network element.
  • the Nsmf_PDUSession_UpdateSMContext request may include a handover completion indication.
  • the method provided in this embodiment of the present application may further include:
  • Step 329 The SMF network element sends an N4 session modification request to the T-UPF network element.
  • Step 330 The T-UPF network element sends an N4 session modification response to the SMF network element.
  • the method provided in this embodiment of the present application may further include:
  • Step 331 The SMF network element sends an N4 session modification request to the S-UPF network element.
  • Step 332 The S-UPF network element sends an N4 session modification response to the SMF network element.
  • Step 333 The SMF network element sends an N4 session modification request to UPF (PSA).
  • PSA UPF
  • Step 334 The S-UPF network element sends an N4 session modification response to the SMF.
  • the downlink user plane data sent by the network to the terminal is sent to the T-UPF network element through UPF (PSA), and then sent to the T-RAN device by the T-UPF network element, and then sent to the terminal by the T-RAN device.
  • PSA UPF
  • the SMF network element sends an Nsmf_PDUSession_UpdateSMContext response containing the PDU session identifier to the T-AMF network element.
  • the terminal initiates a mobile registration update process.
  • the SMF network element sends an N4 session connection release request to the S-UPF network element.
  • the S-UPF network element sends an N4 session release response to the SMF network element.
  • the AMF network element sends a terminal context release command to the S-RAN device.
  • the S-RAN device sends the terminal context release completion to the AMF network element.
  • each network element such as a communication device
  • each network element includes a hardware structure and / or a software module corresponding to each function.
  • the present application can be implemented in the form of hardware or a combination of hardware and computer software. Whether a function is executed by hardware or computer software driven hardware depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.
  • the embodiments of the present application may divide the functional units of the communication device according to the above method examples.
  • each functional unit may be divided corresponding to each function, or two or more functions may be integrated into one processing unit.
  • the above integrated unit may be implemented in the form of hardware or software functional unit. It should be noted that the division of the units in the embodiments of the present application is schematic, and is only a division of logical functions. In actual implementation, there may be another division manner.
  • FIG. 18 shows a schematic structural diagram of a communication apparatus provided by an embodiment of the present application.
  • the communication apparatus may be the source access network device in the embodiment of the present application, or may be applied to the source access network device.
  • the communication device may be used to perform the actions of the source access network device or the S-RAN device in the foregoing method embodiments.
  • the communication device includes a sending unit 101 and a processing unit 102.
  • the sending unit 101 is used to support the communication device to execute S101 and S103 in the foregoing embodiment.
  • the processing unit 102 is configured to support the communication device to perform the step of determining that the source access network device receives the first data packet in the foregoing embodiment.
  • the sending unit 101 is also used to support the communication device to execute S109 in the foregoing embodiment.
  • the communication device may further include: a receiving unit 103, configured to support the communication device to execute S108 in the foregoing embodiment.
  • the receiving unit 103 and the sending unit 101 in this application may be the communication interface or communication interface of the source access network device, or the communication interface or communication interface of the chip applied in the source access network device
  • the processing unit 102 may be integrated on the processor of the source access network device or applied to the processor of the chip in the source access network device.
  • FIG. 19 shows a schematic diagram of a possible logical structure of the communication device involved in the foregoing embodiment.
  • the communication apparatus may be a source access network device or a chip applied in the source access network device, and may be used to perform the actions of the source access network device or the S-RAN device in the foregoing method embodiments.
  • the communication device includes a processing module 112 and a communication module 113.
  • the processing module 112 is used to control and manage the operation of the communication device.
  • the processing module 112 is used to perform a message or data processing step on the side of the communication device, for example, to support the communication device to perform the determination in S103 in the above embodiment
  • the communication module 113 is used to support the communication device to execute S101, S103, and S108 in the above embodiment.
  • the communication module 113 is also used to support the communication device to execute S109 in the foregoing embodiment. And / or other processes performed by the communication device for the techniques described herein.
  • the communication device may further include a storage module 111 for storing program codes and data of the communication device.
  • the processing module 112 may be a processor or a controller, for example, it may be a central processor unit, a general-purpose processor, a digital signal processor, an application specific integrated circuit, a field programmable gate array or other programmable logic devices, transistor logic devices, Hardware components or any combination thereof. It can implement or execute various exemplary logical blocks, modules, and circuits described in conjunction with the disclosure of the present application.
  • the processor may also be a combination of computing functions, for example, including one or more microprocessor combinations, a combination of a digital signal processor and a microprocessor, and so on.
  • the communication module 113 may be a transceiver, a transceiver circuit, a communication interface, or the like.
  • the storage module 111 may be a memory.
  • the processing module 112 is the processor 41 or the processor 45
  • the communication module 113 is the communication interface or the transceiver 43
  • the storage module 111 is the memory 42
  • the communication device involved in the present application may be the communication device shown in FIG.
  • the processor 41 and / or processor 45 supports the source access network device to perform the source access determination in S103 in the foregoing embodiment The step of the network device receiving the first data packet.
  • the transceiver 43 is used to support the source access network device to execute S101, S103, and S108 in the foregoing embodiment.
  • the transceiver 43 is also used to support the source access network device to execute S109 in the foregoing embodiment.
  • FIG. 20 shows a schematic structural diagram of another communication apparatus provided by an embodiment of the present application.
  • the communication apparatus may be a target access network device in the embodiment of the present application, or may be applied to a target access network.
  • the communication apparatus may be used to perform the actions of the target access network device or the T-RAN device in the foregoing method embodiments.
  • the communication device includes a sending unit 201 and a receiving unit 202.
  • the sending unit 201 is used to support the communication device to execute S105 in the above embodiment.
  • the receiving unit 202 is used to support the communication device to execute S102 in the foregoing embodiment.
  • the sending unit 201 is also used to support the communication device to execute S105, S106, S107, and S111 in the foregoing embodiment.
  • the receiving unit 202 is also used to support the communication device to execute S110 in the foregoing embodiment.
  • FIG. 21 shows a possible structural schematic diagram of the communication device involved in the above embodiment.
  • the communication device may be a target access network device or be applied to the target access network device In the chip.
  • the communication device includes: a processing module 212 and a communication module 213.
  • the processing module 212 is used to control and manage the operation of the communication device.
  • the processing module 212 is used to support the communication device to perform the operation of performing message or data processing on the communication device side in the foregoing embodiment.
  • the communication module 213 is used to support the communication device to perform the operations of receiving and sending messages or data on the side of the communication device in the foregoing embodiment, for example, S102 and S105 in the foregoing embodiment.
  • the communication module 213 is also used to support the communication device to execute the steps in the foregoing embodiments: S106, S107, S110, and S111. And / or other processes performed by the communication device for the techniques described herein.
  • the communication device may further include a storage module 211 for storing program codes and data of the communication device.
  • the processing module 212 may be a processor or a controller, for example, it may be a central processor unit, a general-purpose processor, a digital signal processor, an application specific integrated circuit, a field programmable gate array or other programmable logic devices, transistor logic devices, Hardware components or any combination thereof. It can implement or execute various exemplary logical blocks, modules, and circuits described in conjunction with the disclosure of the present application.
  • the processor may also be a combination of computing functions, for example, including one or more microprocessor combinations, a combination of a digital signal processor and a microprocessor, and so on.
  • the communication module 213 may be a transceiver, a transceiver circuit, a communication interface, or the like.
  • the storage module 211 may be a memory.
  • the processing module 212 is the processor 41 or the processor 45
  • the communication module 213 is the communication interface or the transceiver 43
  • the storage module 211 is the memory 42
  • the communication device involved in the present application may be the device shown in FIG.
  • the processor 41 or the processor 45 is used to support the target access network device to perform the message on the target access network device side in the foregoing embodiment Or data processing operations.
  • the transceiver 43 is used to support the communication device to perform the operations of receiving and sending messages or data on the side of the communication device in the foregoing embodiments, for example, S102 and S105 in the foregoing embodiments.
  • the transceiver 43 is also used to support the communication device to execute S106, S107, S110, and S111 in the foregoing embodiment.
  • the division of the units in the communication device is only a division of logical functions, and in actual implementation, it may be fully or partially integrated into a physical entity or may be physically separated.
  • the units in the device can be implemented in the form of software calling through processing elements; they can also be implemented in the form of hardware; some units can also be implemented in software through processing elements, and some units can be implemented in hardware.
  • each unit can be a separate processing element, or it can be integrated in a chip of the device.
  • it can also be stored in the memory in the form of a program, which is called and executed by a processing element of the device.
  • All or part of these units can be integrated together or can be implemented independently.
  • the processing element described here may be an integrated circuit with signal processing capabilities.
  • each step of the above method or each unit above may be implemented by an integrated logic circuit of hardware in a processor element or in the form of software invoking through a processing element.
  • the unit in any of the above devices may be one or more integrated circuits configured to implement the above method, for example: one or more specific integrated circuits (Application Specific Integrated Circuit, ASIC), or, one or Multiple microprocessors (digital processor, DSP), or one or more field programmable gate arrays (Field Programmable Gate Array, FPGA), etc.
  • ASIC Application Specific Integrated Circuit
  • DSP digital processor
  • FPGA Field Programmable Gate Array
  • the unit in the device can be implemented in the form of a processing element scheduling program
  • the processing element may be a general-purpose processor, such as a central processing unit (CPU) or other processor that can call a program.
  • CPU central processing unit
  • these units can be integrated together and implemented in the form of a system-on-a-chip (SOC).
  • the above receiving unit is a communication interface or communication interface of the device, which is used to receive signals from other devices.
  • the receiving unit is a communication interface or communication interface that the chip uses to receive signals from other chips or devices.
  • the above sending unit is a communication interface of the device, which is used to send signals to other devices.
  • the sending unit is a communication interface or communication interface used by the chip to send signals to other chips or devices.
  • the 22 is a schematic structural diagram of a chip 150 provided by an embodiment of the present application.
  • the chip 150 includes at least one processor 1510 and a communication interface 1530.
  • the chip 150 further includes a memory 1540.
  • the memory 1540 may include a read-only memory and a random access memory, and provide operation instructions and data to the processor 1510.
  • a part of the memory 1540 may further include non-volatile random access memory (non-volatile random access memory, NVRAM).
  • the memory 1540 stores the following elements, executable modules or data structures, or their subsets, or their extensions:
  • the corresponding operation is performed by calling the operation instruction stored in the memory 1540 (the operation instruction may be stored in the operating system).
  • a possible implementation manner is as follows: the chip used by the source access network device and the target access network device has a similar structure, and different devices may use different chips to achieve their respective functions.
  • the processor 1510 controls the operations of the source access network device and the target access network device.
  • the processor 1510 may also be called a CPU (central processing unit).
  • the memory 1540 may include a read-only memory and a random access memory, and provide instructions and data to the processor 1510.
  • a portion of the memory 1540 may also include non-volatile random access memory (NVRAM).
  • NVRAM non-volatile random access memory
  • the memory 1540, the communication interface 1530, and the memory 1540 are coupled together through a bus system 1520.
  • the bus system 1520 may also include a power bus, a control bus, and a status signal bus. However, for clarity, various buses are marked as the bus system 1520 in FIG. 22.
  • the method disclosed in the above embodiments of the present application may be applied to the processor 1510, or implemented by the processor 1510.
  • the processor 1510 may be an integrated circuit chip with signal processing capabilities. In the implementation process, each step of the above method may be completed by an integrated logic circuit of hardware in the processor 1510 or an instruction in the form of software.
  • the aforementioned processor 1510 may be a general-purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or Other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components.
  • DSP digital signal processor
  • ASIC application specific integrated circuit
  • FPGA field-programmable gate array
  • the methods, steps, and logical block diagrams disclosed in the embodiments of the present application may be implemented or executed.
  • the 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 conjunction with the embodiments of the present application may be directly embodied and executed by a hardware decoding processor, or may be executed and completed by a combination of hardware and software modules in the decoding processor.
  • the software module may be located in a mature storage medium in the art, such as random access memory, flash memory, read-only memory, programmable read-only memory, or electrically erasable programmable memory, and registers.
  • the storage medium is located in the memory 1540, and the processor 1510 reads the information in the memory 1540, and completes the steps of the above method in combination with its hardware.
  • the communication interface 1530 is used to perform the steps of receiving and sending the source access network device and the target access network device in the embodiments shown in FIGS. 11 and 13-17.
  • the processor 1510 is configured to execute processing steps of the source access network device and the target access network device in the embodiments shown in FIGS. 11 and 13-17.
  • the instructions stored in the memory for execution by the processor may be implemented in the form of computer program products.
  • the computer program product may be written in the memory in advance, or may be downloaded in the form of software and installed in the memory.
  • the computer program product includes one or more computer instructions.
  • the computer may be a general-purpose computer, a dedicated computer, a computer network, or other programmable devices.
  • Computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another computer-readable storage medium.
  • the computer instructions can be transmitted from a website site, computer, server, or data center by wire (e.g. Coaxial cable, optical fiber, digital subscriber line (DSL) or wireless (such as infrared, wireless, microwave, etc.) to another website, computer, server or data center.
  • wire e.g. Coaxial cable, optical fiber, digital subscriber line (DSL) or wireless (such as infrared, wireless, microwave, etc.
  • the computer-readable storage medium may be any available medium that can be stored by a computer or a data storage device such as a server, a data center, or the like that includes one or more available medium integration.
  • the available media may be magnetic media (eg, floppy disk, hard disk, magnetic tape), optical media (eg, DVD), or semiconductor media (eg, solid state disk, SSD), or the like.
  • a computer storage medium stores instructions.
  • the source access network device or the chip applied in the source access network device executes S101, S103, S108, S109.
  • a computer storage medium in which instructions are stored in a computer-readable storage medium, and when the instructions are executed, the target access network device or the chip applied in the target access network device executes S102 in the embodiment , S105, S106, S107, S110, S111.
  • the foregoing readable storage medium may include various media that can store program codes, such as a U disk, a mobile hard disk, a read-only memory, a random access memory, a magnetic disk, or an optical disk.
  • a computer program product containing instructions.
  • the computer program product stores instructions, and when the instructions are executed, the source access network device or the chip applied in the source access network device executes the source in the embodiment
  • the access network device executes S101, S103, S108, and S109 in the foregoing embodiment.
  • a computer program product containing instructions.
  • the computer program product stores instructions.
  • the target access network device or the chip applied in the target access network device executes S102, S105, S106, S107, S110, S111.
  • a chip is provided.
  • the chip is applied to a source access network device.
  • the chip includes at least one processor and a communication interface.
  • the communication interface is coupled to at least one processor.
  • the processor is used to execute instructions to execute the embodiments. S101, S103, S108, S109.
  • a chip is provided.
  • the chip is applied to a target access network device.
  • the chip includes at least one processor and a communication interface, and the communication interface is coupled to at least one processor. S102, S105, S106, S107, S110, and S111 in the embodiment.
  • the present application provides a communication system including: the communication device described in FIG. 18, the communication device described in FIG. 20, and a terminal.
  • the present application provides a communication system including: the communication device described in FIG. 19, the communication device described in FIG. 21, and a terminal.

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Abstract

本申请实施例涉及通信技术领域，尤其涉及一种通信方法及装置，用以提升终端在切换接入网设备的过程中接收到的下行数据的可靠性和降低时延。该方案包括：源接入网设备向目标接入网设备发送终端的第一数据包；当源接入网设备确定所述目标接入网设备接收到所述第一数据包时，所述源接入网设备向所述终端发送第一消息，所述第一消息用于指示所述终端切换至所述目标接入网设备。

Description

一种通信方法及装置
本申请要求于2018年11月19日提交国家知识产权局、申请号为201811379025.1、申请名称为“一种通信方法及装置”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本申请实施例涉及通信技术领域，尤其涉及一种通信方法及装置。
背景技术
为了保证业务的连续性，例如，终端从源基站的覆盖范围移动至目标基站的覆盖范围，源基站可以将终端切换至目标基站，以由目标基站为终端提供服务。
通常，在终端从源基站成功切换至目标基站之前，源基站仍会向终端发送下行数据包。但是，在现有的切换过程中，空口的信号质量可能很差，无法保证在终端成功切换到目标基站之前接收到的下行数据包的可靠性。进一步的，在现有的切换流程中，源基站在向终端发送切换命令之后才开始向目标基站发送终端的下行数据包，可能会导致在终端同步到目标基站时，目标基站由于未接收到来自源基站的终端的下行数据包而导致其无法立刻向终端发送下行数据包，进而导致切换时延大的问题。
例如，5G系统需要提供一种支持高可靠低时延通信(Ultra Reliable and Low Latency munications，URLLC)的业务，为了保证URLLC业务，切换过程同样需要保证高可靠性和低时延。因此，现有技术中的切换流程无法满足URLLC业务的高可靠性和低时延需求。
发明内容
本申请实施例提供一种通信方法及装置，用以提升终端在切换接入网设备的过程中接收到的下行数据的可靠性和降低时延。
为了达到上述目的，本申请实施例提供如下技术方案：
第一方面，本申请实施例提供一种通信方法，包括：源接入网设备将发送给终端的第一数据包发送给目标接入网设备。当源接入网设备确定目标接入网设备接收到第一数据包时，源接入网设备向终端发送用于指示终端切换至目标接入网设备的第一消息。
本申请实施例提供一种通信方法，由于在终端切换至目标接入网设备的过程(即源接入网设备向终端发送第一消息之前)中，源接入网设备依旧需要将第一数据包发送给终端。如果在切换过程中由于空口的信号质量差，终端有可能未接收到第一数据包。因此，通过源接入网设备向目标接入网设备发送第一数据包，这样在源接入网设备在确定目标接入网设备接收到第一数据包时，向终端发送指示终端切换至目标接入网设备的第一消息。一方面可以使得目标接入网设备处具有第一数据包。另一方面，在确定目标接入网设备接收到第一数据包之后，再向终端发送第一消息，可以使得在终端从源接入网设备成功切换至目标接入网设备以后，由目标接入网设备将第一数据包再发送给终端。这样可以保证终端在切换过程中无法从源接入网设备处接收到第一数据包的情况下，还可以从目标接入网设备处获取到第一数据包，保证了数据传输的 可靠性。此外，由于源接入网设备发送给目标接入网设备的数据包是在向终端发送切换命令之前，这样与现有技术中在向终端发送切换命令之后才向目标接入网设备发送终端的数据包相比，可以进一步降低时延。
在一种可能的实现方式中，本申请实施例提供的方法还包括：源接入网设备接收来自目标接入网设备的用于指示允许终端切换至目标接入网设备的第一信息，源接入网设备向目标接入网设备发送第一数据包。即源接入网设备接收到允许切换的第一信息，源接入网设备便向目标接入网设备发送第一数据包。
在一种可能的实现方式中，在源接入网设备向目标接入网设备发送第一数据包之前，本申请实施例提供的方法还包括：源接入网设备根据第一信息，确定目标接入网设备允许终端切换至所述目标接入网设备。这样源接入网设备确定目标接入网设备同意切换时，开始发送第一数据包，可以避免因为目标接入网设备不同意切换，盲目发送第一数据包引起的空口资源浪费。
在一种可能的实现方式中，第一数据包包括复制数据包，本申请实施例提供的方法还包括：源接入网设备获得复制数据包；或者，当满足为终端切换接入网设备的条件时，源接入网设备获得复制数据包。
在一种可能的实现方式中，源接入网设备获得复制数据包，包括：源接入网设备对终端的数据包中满足预设条件的数据包进行复制，得到复制数据包。其中，满足预设条件的数据包包括以下情况中的至少一种：使用预设服务质量QoS流的数据包，预设分组数据单元PDU会话上的数据包，丢包率小于或等于预设门限值的数据包，或者预设无线承载上的数据包。这样可以根据预设条件选择需要复制的数据包，以首先保证满足预设条件的数据包可靠性。
在一种可能的实现方式中，源接入网设备获得复制数据包，包括：源接入网设备对终端的数据包进行复制，得到复制数据包。
在一种可能的实现方式中，本申请实施例提供的方法还包括：源接入网设备确定满足为终端切换接入网设备的条件，源接入网设备执行上述复制步骤。
在一种可能的实现方式中，本申请实施例提供的方法还包括：源接入网设备向目标接入网设备发送序列号SN状态信息，SN状态信息用于目标接入网设备向终端发送数据包。通过发送SN状态信息便于目标接入网设备设置数据包的SN。
在一种可能的实现方式中，源接入网设备确定目标接入网设备接收到第一数据包，包括：源接入网设备接收目标接入网设备发送的第二消息，第二消息用于指示目标接入网设备接收到第一数据包；或者，源接入网设备根据时延信息确定目标接入网设备接收到第一数据包。
在一种可能的实现方式中，本申请实施例提供的方法还包括：源接入网设备根据第一数据包的QoS信息，确定时延信息；或，源接入网设备从会话管理功能获取时延信息。
第二方面，本申请实施例提供一种通信方法，包括：目标接入网设备向源接入网设备发送用于指示允许终端切换至目标接入网设备的第一信息；目标接入网设备接收来自源接入网设备的终端的第一数据包；当终端从源接入网设备成功切换至目标接入网设备时，目标接入网设备向终端发送第一数据包。
在一种可能的实现方式中，本申请实施例提供的方法还包括：目标接入网设备向源接入网设备发送用于指示目标接入网设备接收到第一数据包的第二消息。
在一种可能的实现方式中，本申请实施例提供的方法还包括：目标接入网设备接收来自源接入网设备的序列号SN状态信息，SN状态信息用于目标接入网设备向终端发送数据包；目标接入网设备根据所述SN状态信息和处理来自源接入网设备未携带有SN的数据包，得到第二数据包；未携带有SN的数据包为第一数据包中的数据包或者源接入网设备中的终端的数据包；目标接入网设备向终端发送第二数据包。第二数据包的SN根据SN状态信息确定。
第三方面，本申请实施例提供一种通信装置，该通信装置可以实现第一方面或第一方面的任意一种可能的实现方式中描述的一种通信方法，因此也可以实现第一方面或第一方面任意一种可能的实现方式中的有益效果。该一种通信装置可以为源接入网设备，也可以为可以支持源接入网设备实现第一方面或第一方面的任意一种可能的实现方式中的装置。例如应用于源接入网设备中的芯片。该一种通信装置可以通过软件、硬件、或者通过硬件执行相应的软件实现上述方法。
一种示例，该通信装置，包括：发送单元和处理单元。其中，发送单元，用于向目标接入网设备发送终端的第一数据包。发送单元，还用于当处理单元确定目标接入网设备接收到第一数据包时，向终端发送用于指示终端切换至目标接入网设备的第一消息。
在一种可能的实现方式中，通信装置还包括：接收单元，用于接收来自目标接入网设备的用于指示允许终端切换至目标接入网设备的第一信息；发送单元，还用于向目标接入网设备发送终端的第一数据包。
在一种可能的实现方式中，第一数据包包括复制数据包，所述处理单元，还用于获得复制数据包；或者，处理单元，还用于当满足为终端切换接入网设备的条件时，获得复制数据包。
在一种可能的实现方式中，处理单元，还具体用于对终端的数据包中满足预设条件的数据包进行复制，得到复制数据包。其中，满足预设条件的数据包包括以下情况中的至少一种：使用预设服务质量QoS流的数据包，预设分组数据单元PDU会话上的数据包，丢包率小于或等于预设门限值的数据包，或者预设无线承载上的数据包。
在一种可能的实现方式中，处理单元，还具体用于对终端的数据包进行复制，得到复制数据包。
在一种可能的实现方式中，处理单元，还用于确定满足为终端切换接入网设备的条件，执行上述复制步骤。
在一种可能的实现方式中，发送单元，还用于向目标接入网设备发送序列号SN状态信息，SN状态信息用于目标接入网设备向终端发送数据包。
在一种可能的实现方式中，接收单元，用于接收目标接入网设备发送的用于指示目标接入网设备接收到第一数据包的第二消息，接收单元，具体用于根据第二消息，确定目标接入网设备接收到第一数据包。或者，处理单元，用于根据时延信息确定目标接入网设备接收到第一数据包。这样便于源接入网设备通过多种途径确定目标接入网设备接收到第一数据包。
在一种可能的实现方式中，处理单元，还用于根据第一数据包的QoS信息，确定时延信息；或，处理单元，还用于从会话管理功能网元获取时延信息。
另一种示例，本申请实施例还提供的一种通信装置，该通信装置可以为源接入网设备或者为应用于源接入网设备中的芯片，该通信装置包括：通信接口和一个或多个处理器。
源接入网设备通过通信接口与其他设备通信，当一个或多个处理器执行指令时，源接入网设备执行如上述第一方面所描述的通信方法。
例如，通信接口用于支持该一种通信装置执行第一方面至第一方面的任意一种可能的实现方式中所描述的在该一种通信装置侧进行消息/数据接收和发送的步骤。处理器用于支持该一种通信装置执行第一方面至第一方面的任意一种可能的实现方式中所描述的在该一种通信装置侧进行消息/数据处理的步骤。具体相应的步骤可以参考第一方面至第一方面的任意一种可能的实现方式中的描述，在此不再赘述。
可选的，该一种通信装置的通信接口和处理器相互耦合。
可选的，该一种通信装置还可以包括存储器，用于存储计算机程序代码，计算机程序代码包括指令。可选的，处理器、通信接口和存储器相互耦合。
第四方面，本申请实施例提供一种通信装置，该通信装置可以实现第二方面或第二方面的任意一种可能的实现方式中描述的一种通信方法，因此也可以实现第二方面或第二方面任意一种可能的实现方式中的有益效果。该一种通信装置可以为目标接入网设备，也可以为可以支持目标接入网设备实现第二方面或第二方面的任意一种可能的实现方式中的装置。例如应用于目标接入网设备中的芯片。该一种通信装置可以通过软件、硬件、或者通过硬件执行相应的软件实现上述方法。
示例性的，一种通信装置，包括：发送单元，用于向源接入网设备发送用于指示允许终端切换至目标接入网设备的第一信息。接收单元，用于接收来自源接入网设备的终端的第一数据包。发送单元，用于当终端从源接入网设备成功切换至目标接入网设备时，向终端发送第一数据包。
在一种可能的实现方式中，发送单元，还用于向源接入网设备发送用于指示目标接入网设备接收到第一数据包的第二消息。
在一种可能的实现方式中，接收单元，还用于接收来自源接入网设备的序列号SN状态信息，SN状态信息用于目标接入网设备向终端发送数据包。发送单元，还用于根据SN状态信息和处理来自源接入网设备未携带有SN的数据包，得到第二数据包；未携带有SN的数据包为第一数据包中的数据包或者源接入网设备中的终端的数据包，发送单元，还用于向终端发送第二数据包。
另一种示例，本申请实施例还提供的一种通信装置，该通信装置可以为目标接入网设备或者为应用于目标接入网设备中的芯片，该通信装置包括：通信接口和一个或多个处理器。
目标接入网设备通过通信接口与其他设备通信，当一个或多个处理器执行指令时，目标接入网设备执行如上述第二方面所描述的通信方法。
例如，通信接口用于支持该通信装置执行第二方面至第二方面的任意一种可能的实现方式中所描述的在该一种通信装置侧进行消息/数据接收和发送的步骤。处理器用 于支持该一种通信装置执行第二方面至第二方面的任意一种可能的实现方式中所描述的在该一种通信装置侧进行消息/数据处理的步骤。具体相应的步骤可以参考第二方面至第二方面的任意一种可能的实现方式中的描述，在此不再赘述。
可选的，该一种通信装置的通信接口和处理器相互耦合。
可选的，该一种通信装置还可以包括存储器，用于存储计算机程序代码，计算机程序代码包括指令。可选的，处理器、通信接口和存储器相互耦合。
第五方面，本申请实施例提供一种计算机可读存储介质，该计算机可读存储介质中存储有指令，当指令在计算机上运行时，使得计算机执行第一方面或第一方面的各种可能的实现方式中所描述的一种通信方法。
第六方面，本申请提供一种计算机可读存储介质，该计算机可读存储介质中存储有指令，当指令在计算机上运行时，使得计算机执行第二方面或第二方面的各种可能的实现方式中所描述的一种通信方法。
第七方面，本申请提供一种包括指令的计算机程序产品，当指令在计算机上运行时，使得计算机执行第一方面或第一方面的各种可能的实现方式中所描述的一种通信方法。
第八方面，本申请提供一种包括指令的计算机程序产品，当指令在计算机上运行时，使得计算机执行第二方面或第二方面的各种可能的实现方式中所描述的一种通信方法。
第九方面，本申请实施例提供一种芯片，该芯片包括处理器和通信接口，通信接口和处理器耦合，处理器用于运行计算机程序或指令，以实现第一方面或第一方面的各种可能的实现方式中所描述的一种通信方法。通信接口用于与所述芯片之外的其它模块进行通信。
第十方面，本申请实施例提供一种芯片，该芯片包括处理器和通信接口，通信接口和处理器耦合，处理器用于运行计算机程序或指令，以实现第二方面或第二方面的各种可能的实现方式中所描述的一种通信方法。通信接口用于与所述芯片之外的其它模块进行通信。
第十一方面，本申请实施例提供一种通信系统，该方法包括：第三方面及第三方面的各种可能的实现方式描述的源接入网设备，以及第四方面及第四方面的各种可能的实现方式描述的目标接入网设备。
本申请中第二方面、第三方面、第四方面、第五方面、第六方面、第七方面、第八方面、第九方面、第十方面以及第十一方面及其各种实现方式的有益效果，可以参考第一方面及其各种实现方式中的有益效果分析，此处不再赘述。
附图说明
图1-图4为本申请实施例提供的一种通信系统示意图；
图5为本申请实施例提供的一种5G通信系统示意图；
图6为本申请实施例提供的另一种5G通信系统示意图；
图7为本申请实施例提供的一种基站的结构示意图；
图8为本申请实施例提供的另一种基站的结构示意图；
图9为本申请实施例提供的另一种通信系统示意图；
图10为本申请实施例提供的一种接入网设备的结构示意图；
图11为本申请实施例提供的一种通信方法的流程示意图一；
图12为本申请实施例提供的一种数据包发送示意图；
图13为本申请实施例提供的一种通信方法的流程示意图二；
图14为本申请实施例提供的一种通信方法的流程示意图三；
图15为本申请实施例提供的一种通信方法的流程示意图四；
图16为本申请实施例提供的一种具体实施例的流程示意图；
图17为本申请实施例提供的另一种具体实施例的流程示意图；
图18-图21为本申请实施例提供的一种通信装置的结构示意图；
图22为本申请实施例提供的一种芯片的结构示意图。
具体实施方式
本申请实施例的技术方案可以应用于各种通信系统。例如：全球移动通信系统(global system for mobile communication，GSM)、演进通用无线陆地接入(evolved universal terrestrial radio access，E-UTRA)系统、通用移动通信系统(universal mobile telecommunications system，UMTS)以及UMTS演进版本、长期演进(long term evolution，LTE)和基于LTE演进的各种版本、第五代(5th-generation，5G)通信系统、以及新空口(new radio，NR)等下一代通信系统中。此外，上述通信系统还可以适用于面向未来的通信技术，都适用本申请实施例提供的技术方案。
需要说明的是，本申请实施例中，“示例性的”或者“例如”等词用于表示作例子、例证或说明。本申请实施例中被描述为“示例性的”或者“例如”的任何实施例或设计方案不应被解释为比其他实施例或设计方案更优选或更具优势。确切而言，使用“示例性的”或者“例如”等词旨在以具体方式呈现相关概念。
本申请中，“至少一个”是指一个或者多个，“多个”是指两个或两个以上。“和/或”，描述关联对象的关联关系，表示可以存在三种关系，例如，A和/或B，可以表示：单独存在A，同时存在A和B，单独存在B的情况，其中A，B可以是单数或者复数。字符“/”一般表示前后关联对象是一种“或”的关系。“以下至少一项(个)”或其类似表达，是指的这些项中的任意组合，包括单项(个)或复数项(个)的任意组合。例如，a，b，或c中的至少一项(个)，可以表示：a，b，c，a-b，a-c，b-c，或a-b-c，其中a，b，c可以是单个，也可以是多个。本申请实施例中A或B，可以表示：单独存在A，同时存在A和B，单独存在B的情况，其中A，B可以是单数或者复数。
另外，为了便于清楚描述本申请实施例的技术方案，在本申请的实施例中，采用了“第一”、“第二”等字样对功能和作用基本相同的相同项或相似项进行区分。本领域技术人员可以理解“第一”、“第二”等字样并不对数量和执行次序进行限定，并且“第一”、“第二”等字样也并不限定一定不同。
本申请实施例描述的系统架构以及业务场景是为了更加清楚的说明本申请实施例的技术方案，并不构成对于本申请实施例提供的技术方案的限定，本领域普通技术人员可知，随着网络架构的演变和新业务场景的出现，本申请实施例提供的技术方案对于类似的技术问题，同样适用。
在当前的4G网络中，LTE系统中的演进式基站(evolved Node Base Station，eNB) (可以称为LTE eNB)通过S1接口与4G核心网络(例如，分组核心网(Evolved Packet Core，EPC))连接，不同的LTE eNB之间通过X2接口连接。例如，图1中LTE eNB1和LTE eNB2之间通过X2接口连接。图1示出了LTE系统的网络架构，其中，X2接口支持两个LTE eNB之间的数据和信令的直接传输。
示例性的，X2接口也分为两个接口，例如，X2-C接口和X2-U接口。其中，X2-C接口用于控制面，X2-U接口用于用户面。X2-C接口用于传输LTE eNB之间信令。X2-U接口用于传输LTE eNB之间的数据。
在LTE中终端通过各自接入的LTE eNB与EPC进行数据传输或者信令传输。
随着移动通信技术的不断发展，4G网络逐渐向5G网络演进。在演进过程中，LTE系统可演进为eLTE系统。
在eLTE系统中，EPC网和下一代核心(The Next-Generation Core，NG-Core)网并存。eLTE系统中的eNB称为eLTE eNB，具备接入到NG-Core网功能的终端称为下一代终端(例如，图中的终端1和终端2)。eLTE eNB可接入到EPC网，也可接入到NG-Core网。与eLTE eNB无线连接的终端1，通过eLTE eNB可以接入到EPC网，也可以接入到NG-Core网。如图2所示，eLTE eNB通过S1接口与EPC网连接，也可通过其他相应接口(图2中用NG表示)接入到NG-Core网。与eLTE eNB连接的终端1可通过eLTE eNB接入到EPC网，也可通过eLTE eNB接入到NG-Core网。与eLTE eNB连接的终端，可通过LTE eNB接入EPC网。图2中用NR gNB表示仅接入到NG-Core网的基站，LTE eNB与eLTE eNB之间通过X2接口连接，eLTE eNB与NR gNB之间通过Xn接口连接。
4G网络的核心网设备与5G网络的核心网设备可以互通(英文：interworking)。结合图2，图3示出了在4G网络的核心网设备与5G网络的核心网设备互通的场景中，5G网络的通信系统中各个设备之间的组成结构。
核心网设备具备用户面功能和控制面功能，一般的，采用用户面网元表示能够实现核心网设备的用户面功能的设备，采用控制面网元表示能够实现核心网设备的控制面功能的设备，用户面网元与控制面网元可以集成在同一设备，也可以独立设置。本申请实施例以用户面网元与控制面网元独立设置为例进行说明。
在图3中，4G网络的归属用户服务器(Home Subscriber Server，HSS)与5G网络的统一数据管理(Unified Data Management，UDM)网元集成在同一设备，4G网络的公用数据网网关(Public Data Network Gateway，PGW)的控制面PGW-C网元与5G网络的会话管理功能(Session Management Function，SMF)网元集成在同一设备，4G网络的PGW-U网元与5G网络的用户面功能(User plane Function，UPF)网元集成在同一设备。图3中的移动性管理实体(Mobility Management Entity，MME)为4G网络的控制面网元，MME与LTE eNB通过S1-MME接口连接。核心接入和移动性管理功能(Core Access and Mobility Management Function，AMF)网元为5G网络中的控制面网元，AMF网元与NR gNB/eLTE eNB通过N2接口连接，通过N1接口与终端3连接。MME与AMF网元之间可以通过Nx接口连接，Nx接口也可以不存在，因此，图3中虚线表示Nx接口。其中，在5G中AMF网元与PCF网元通过N15接口连接，PGW-C网元与SMF网元通过N7接口与PCF网元连接。服务网关(Serving GateWay， SGW)为4G网络中负责数据包的路由和转发等处理的设备。此外，图3中还示出了S5-U、S5-C、S11、S1-U、S6a、N1、N2、N3、N4、N7、N8、N10、N11、N15等相关接口，此处不再详细描述这些接口。
在当前的5G网络中，NR系统中的每个下一代节点B(The Next Generation Node B，gNB)，本申请实施例将其称为NR gNB，通过N2接口与NG-Core网连接，不同的NR gNB之间通过Xn接口连接，例如，gNB1和gNB2之间通过Xn接口连接。每个NR gNB均与NR系统中的至少一个终端连接。图4示出了NR系统的网络架构。在实际应用中上述多个设备之间的连接为无线连接，为了方便直观地表示各个设备之间的连接关系，图4中采用实线示意。
其中，若图4所示的通信系统应用于5G网络，则如图5所示，gNB所对应的网元或者实体可以为RAN、NG-Core网包括的网元可以为SMF网元、UPF网元、策略控制网元可以为(Policy Control Function，PCF)、应用功能(Application Function，AF)网元、鉴权服务器功能(Authentication Server Function，AUSF)网元、UDM网元、网络能力开放功能(Network Exposure Function，NEF)网元、网络仓库贮存功能(Network Repository Function，NRF)网元以及数据网络(Data Network，DN)、安全锚点功能(Security Anchor Function，SEAF)网元或者网络切片选择功能(Network Slice Selection Function，NSSF)网元等。本申请实施例对此不作具体限定。
其中，终端通过N1接口(简称N1)与AMF网元通信。AMF网元通过N11接口(简称N11)与SMF网元通信。SMF网元通过N4接口(简称N4)与一个或者多个UPF网元通信。一个或多个UPF网元中任意两个UPF网元通过N9接口(简称N9)通信。UPF网元通过N6接口(简称N6)与数据网络(Data Network，DN)通信。终端通过接入网设备(例如，RAN设备)接入网络。接入网设备与AMF网元之间通过N2接口(简称N2)通信。SMF网元通过N7接口(简称N7)与PCF网元通信，PCF网元通过N5接口与AF网元通信。接入网设备通过N3接口(简称N3)与UPF网元通信。任意两个或两个以上的AMF网元之间通过N14接口(简称N14)通信。SMF网元通过N10接口(简称N10)与UDM网元通信。AMF网元通过N12接口(简称N12)与AUSF网元通信。AUSF网元通过N13接口(简称N13)与UDM网元通信。AMF网元通过N8接口(简称N8)与UDM网元通信。
需要说明的是，图5中的各个网元之间的接口名字只是一个示例，具体实现中接口名字可能为其他名字，本申请实施例对此不作具体限定。
需要说明的是，图5的接入网设备、AF网元、AMF网元、SMF网元、AUSF网元、UDM网元、UPF网元和PCF网元等仅是一个名字，名字对设备本身不构成限定。在5G网络以及未来其它的网络中，接入网设备、AF网元、AMF网元、SMF网元、AUSF网元、UDM网元、UPF网元和PCF网元所对应的网元也可以是其他的名字，本申请实施例对此不作具体限定。例如，该UDM网元还有可能被替换为HSS或者用户签约数据库(User Subscription Database，USD)或者数据库实体，等等，在此进行统一说明，后续不再赘述。
图6示出了基于服务化接口的非漫游架构的5G网络，当然，5G网络还可以采用如图6所示的，基于参考点的非漫游架构。
其中，AMF网元：属于核心网网元，主要负责信令处理部分，例如：接入控制、移动性管理、附着与去附着以及网关选择等功能。AMF网元为终端中的会话提供服务的情况下，会为该会话提供控制面的存储资源，以存储会话标识、与会话标识关联的SMF网元标识等。
(无线)接入网((Radio)Access Network，(R)AN)设备：包括RAN设备和AN设备。RAN设备主要是第三代合作伙伴计划(3rd Generation Partnership Project，3GPP)网络无线网络设备，AN可以是非(non)-3GPP定义的接入网设备。
RAN设备：主要负责空口侧的无线资源管理、服务质量(quality of service，QoS)管理、数据压缩和加密等功能。所述接入网设备可以包括各种形式的基站，例如：宏基站，微基站(也称为小站)，中继站，接入点等。在采用不同的无线接入技术的系统中，具备基站功能的设备的名称可能会有所不同，例如，在第五代(5th generation，5G)系统中，称为RAN。在LTE系统中，称为演进的节点B(evolved NodeB，eNB或者eNodeB)。在第三代(3rd generation，3G)系统中，称为节点B(Node B)等。
AN设备：允许终端和3GPP核心网之间采用非3GPP技术互连互通。其中，非3GPP技术例如：无线保真(Wireless Fidelity，Wi-Fi)、全球微波互联接入(Worldwide Interoperability for Microwave Access，WiMAX)、码分多址(Code Division Multiple Access，CDMA)网络等。
SMF网元：负责用户面网元选择，用户面网元重定向，因特网协议(internet protocol，IP)地址分配，承载的建立、修改和释放以及QoS控制。
UPF网元：负责终端中用户数据的转发和接收。可以从数据网络接收用户数据，通过接入网设备传输给终端。UPF网元还可以通过接入网设备从终端接收用户数据，转发到数据网络。UPF网元中为终端提供服务的传输资源和调度功能由SMF网元管理控制。
PCF网元：主要支持提供统一的策略框架来控制网络行为，提供策略规则给控制层网络功能，同时负责获取与策略决策相关的用户签约信息。
AUSF网元：主要提供认证和鉴权功能。
NEF网元：主要支持3GPP网络和第三方应用安全的交互，NEF网元能够安全的向第三方开放网络能力和事件，用于加强或者改善应用服务质量，3GPP网络同样可以安全的从第三方获取相关数据，用以增强网络的智能决策；同时该NEF网元支持从统一数据库恢复结构化数据或者向统一数据库中存储结构化数据。
统一数据库(unified data repository，UDR)：主要负责存储结构化数据，存储的内容包括签约数据和策略数据、对外暴露的结构化数据和应用相关的数据。
AF网元：主要支持与3GPP核心网交互来提供服务。例如影响数据路由决策，策略控制功能或者向网络侧提供第三方的一些服务。
本申请实施例中的终端可以是指向用户提供语音和/或数据连通性的设备，具有无线连接功能的手持式设备、或连接到无线调制解调器的其他处理设备。无线终端可以经RAN与一个或多个核心网进行通信。无线终端可以是用户设备(user equipment，UE)、手持终端、笔记本电脑、用户单元(subscriber unit)、蜂窝电话(cellular phone)、智能电话(smart phone)、无线数据卡、个人数字助理(personal digital assistant，PDA) 电脑、平板型电脑、无线调制解调器(modem)、手持设备(handheld)、膝上型电脑(laptop computer)、无绳电话(cordless phone)或者无线本地环路(wireless local loop，WLL)台、机器类型通信(machine type communication，MTC)终端或是其他可以接入网络的设备。终端与接入网设备之间采用某种空口技术(例如，3GPP接入技术或者非3GPP接入技术)相互通信。
由于未来接入网可以采用云无线接入网(cloud radio access network，C-RAN)架构来实现，一种可能的方式是将传统基站的协议栈架构和功能分割为两部分，一部分称为集中单元(central unit，CU)，另一部分称为分布单元(distributed unit，DU)，而CU和DU的实际部署方式比较灵活，例如多个基站的CU部分集成在一起，组成一个规模较大的功能实体。如图7所示，其为本申请实施例提供的一种网络架构的示意图。如图7所示，该网络架构包括核心网(core network，CN)设备和接入网(以RAN为例)设备。其中RAN设备包括基带装置和射频装置，其中基带装置可以由一个节点实现，也可以由多个节点实现，射频装置可以从基带装置拉远独立实现，也可以集成基带装置中，或者部分拉远部分集成在基带装置中。例如，在LTE通信系统中，RAN设备(eNB)包括基带装置和射频装置，其中射频装置可以相对于基带装置拉远布置(例如射频拉远单元(radio remote unit，RRU)相对于基带处理单元(building base band unit，BBU))，RAN设备由一个节点实现，该节点用于实现无线资源控制(radio resource control，RRC)、分组数据汇聚层协议(packet data convergence protocol，PDCP)、无线链路控制(radio link control，RLC)、媒体接入控制(medium access control，MAC)等协议层的功能。再如，在一种演进结构中，基带装置可以包括CU和DU，多个DU可以由一个CU集中控制。如图7所示，CU和DU可以根据无线网络的协议层划分，例如分组数据汇聚层协议层及以上协议层的功能设置在CU，PDCP以下的协议层，例如RLC层和MAC层等的功能设置在DU。
这种协议层的划分仅仅是一种举例，还可以在其它协议层划分，例如在RLC层划分，将RLC层及以上协议层的功能设置在CU，RLC层以下协议层的功能设置在DU；或者，在某个协议层中划分，例如将RLC层的部分功能和RLC层以上的协议层的功能设置在CU，将RLC层的剩余功能和RLC层以下的协议层的功能设置在DU。此外，也可以按其它方式划分，例如按时延划分，将处理时间需要满足时延要求的功能设置在DU，不需要满足该时延要求的功能设置在CU。
此外，射频装置可以拉远，不放在DU中，也可以集成在DU中，或者部分拉远部分集成在DU中，在此不作任何限制。
此外，请继续参考图8，相对于图8所示的架构，还可以将CU的控制面(control plane，CP)和用户面(user plane，UP)分离，分成不同实体来实现，分别为控制面CU实体(CU-CP实体)和用户面CU实体(CU-UP实体)。
在以上网络架构中，CU产生的数据可以通过DU发送给终端，或者终端产生的数据可以通过DU发送给CU。DU可以不对该数据进行解析而直接通过协议层封装后传给终端或CU。例如，RRC或PDCP层的数据最终会处理为物理层(physical layer，PHY)的数据发送给终端，或者，由接收到的PHY层的数据转变而来。在这种架构下，该RRC或PDCP层的数据，即也可以认为是由DU发送的。
在以上实施例中CU划分为RAN中接入网设备，此外，也可以将CU划分为CN中的接入网设备，在此不做限制。
本申请以下实施例中的装置，根据其实现的功能，可以位于终端或接入网设备。当采用以上CU-DU的结构时，接入网设备可以为CU节点、或DU节点、或包括CU节点和DU节点功能的RAN设备。
可以理解的是，当接入网设备可以划分为CU或DU时。如图7所示，如果一个接入网设备覆盖一个或者多个小区可以指该接入网设备的CU覆盖一个或者多个小区，也可以指该接入网设备的DU覆盖一个或者多个小区。
当接入网设备可以划分为CU和DU时，两个接入网设备之间通过Xn接口通信。5G核心网(5G Core，5GC)与每个接入网设备之间的接口为NG接口，其中，NG接口包括控制面接口和数据面接口，例如，控制面接口为N2接口，数据面接口为N3接口。
如图9所示，图9以接入网设备为gNB为例，从gNB1切换至gNB2可以指从gNB1的CU切换至gNB2的CU，或者从gNB1至gNB2的CU。或者从gNB1的DU切换至gNB2的DU，或从gNB1切换至gNB2的DU。
在图2-图9所示的通信系统中，无论是LTE eNB、或eLTE eNB还是gNB，一个基站一般可以覆盖一个或者多个小区。每个小区有一定的覆盖范围，该覆盖范围相对固定。如果终端在移动过程中，离开服务小区而进入另一个小区，如果该另一个小区和服务小区由不同的基站管理(例如，服务小区属于源基站，另一个小区属于目标基站)。该终端需要在现有的移动管理技术的控制下从源基站切换到目标基站。
现有第五代移动通信技术切换流程定义了包括基于Xn接口的切换流程和基于N2的切换流程。其中，Xn接口为两个接入网设备之间的接口，即Xn接口的切换流程可以理解为在源无线接入网(Source Radio Access Network，S-RAN)设备确定为终端切换接入网设备的情况下，由S-RAN设备向目标无线接入网(target Radio Access Network，T-RAN)设备发送切换请求；在S-RAN设备确定T-RAN设备同意将终端切换至T-RAN设备的情况下，S-RAN设备向终端发起切换流程，以将终端切换至T-RAN设备。N2为接入网设备和AMF网元之间的接口，即N2的切换流程可以理解为：在S-RAN设备确定为终端切换接入网设备的情况下，S-RAN设备向S-AMF网元发送切换请求。由S-AMF网元选择T-AMF网元之后，再由T-AMF网元将切换请求发送给T-RAN设备。当T-AMF网元从T-RAN设备切换请求确认之后，将切换请求确认通过S-AMF网元发送给-RAN设备，在S-RAN设备确定T-RAN设备同意将终端切换至T-RAN设备的情况下，S-RAN设备向终端发起切换流程，以将终端切换至T-RAN设备。
无论是N2的切换流程还是Xn接口的切换流程，S-RAN设备在确定执行切换流程(即向终端发送切换命令)之前需要向终端发送下行数据包。
由于在切换过程中S-RAN设备可能需要将终端的数据包发送给终端，在目前的切换流程中，S-RAN设备在确定切换时，继续发送终端的数据包直到向终端发送切换命令。但是在S-RAN设备确定为终端切换接入网设备之后，空口的通信质量可能变得很差。如果在此过程中S-RAN设备依旧向终端发送数据包，有可能存在因为通信质量很差导致终端无法接收到S-RAN设备发送的数据包，因此数据包的可靠性降低。且 S-RAN设备在向终端发送切换命令之后，才向T-RAN设备发送数据包，这导致一定的时延。
基于此，本申请实施例提供一种通信方法，该方法通过源接入网设备在向终端发送切换命令之前将终端的数据包(例如，源数据包)进行复制，得到复制数据包。然后源接入网设备将复制数据包发送给为终端选择的目标接入网设备。此外，源接入网设备还需将源数据包继续发送给终端。由于终端从源接入网设备成功切换至目标接入网设备之前，源接入网设备依旧需要向终端发送源数据包，而终端从源接入网设备成功切换至目标接入网设备之后，目标接入网设备可以将基于源数据包得到的复制数据包发送给终端。这样可以保证终端若终端在切换过程中无法从源接入网设备处接收到源数据包的情况下，还可以从目标接入网设备处获取到复制数据包，保证了数据传输的可靠性。此外，由于发送给目标接入网设备的数据包是在向终端发送切换命令之前，这样与现有技术中在向终端发送切换命令之后才向目标接入网设备发送终端的数据包相比，可以进一步降低时延。
需要指出的是，本申请各实施例之间可以相互借鉴或参考，例如，相同或相似的步骤，方法实施例和装置实施例之间，均可以相互参考，不予限制。
图10为本申请实施例提供的一种接入网设备的组成示意图。源接入网设备和目标接入网设备可以参考如图10所示的接入网设备的结构。如图10所示，接入网设备可以包括至少一个处理器41和存储器42。
下面结合图10对接入网设备的各个构成部件进行具体的介绍：
处理器41是接入网设备的控制中心，可以是一个处理器，也可以是多个处理元件的统称。例如，处理器41是一个CPU，也可以是特定集成电路(Application Specific Integrated Circuit，ASIC)，或者是被配置成实施本申请实施例的一个或多个集成电路，例如：一个或多个微处理器(Digital Signal Processor，DSP)，或，一个或者多个现场可编程门阵列(Field Programmable Gate Array，FPGA)。
其中，处理器41可以通过运行或执行存储在存储器42内的软件程序，以及调用存储在存储器42内的数据，执行接入网设备的各种功能，例如，用于执行本申请各方法实施例中源接入网设备或目标接入网设备的动作。
在具体的实现中，作为一种实施例，处理器41可以包括一个或多个CPU，例如图10中所示的CPU 0和CPU 1。
在具体实现中，作为一种实施例，接入网设备可以包括多个处理器，例如图10中所示的处理器41和处理器45。这些处理器中的每一个可以是一个单核处理器(single-CPU)，也可以是一个多核处理器(multi-CPU)。这里的处理器可以指一个或多个设备、电路、和/或用于处理数据(例如计算机程序指令)的处理核。
存储器42可以是只读存储器(Read-Only Memory，ROM)或可存储静态信息和指令的其他类型的静态存储设备，随机存取存储器(Random Access Memory，RAM)或者可存储信息和指令的其他类型的动态存储设备，也可以是电可擦可编程只读存储器(Electrically Erasable Programmable Read-Only Memory，EEPROM)、只读光盘(Compact Disc Read-Only Memory，CD-ROM)或其他光盘存储、光碟存储(包括压缩光碟、激光碟、光碟、数字通用光碟、蓝光光碟等)、磁盘存储介质或者其他磁存 储设备、或者能够用于携带或存储具有指令或数据结构形式的期望的程序代码并能够由计算机存取的任何其他介质，但不限于此。
可选地，接入网设备还包括：总线44。存储器42可以是独立存在，通过总线44与处理器41相连接。存储器42也可以和处理器41集成在一起。
其中，存储器42用于存储执行本申请方案的软件程序。
可选地，接入网设备还包括：收发器43。
收发器43，用于与其他设备或通信网络通信。如用于与终端，核心网设备(例如，AMF网元、SMF网元、UPF网元等)，以太网，RAN，无线局域网(Wireless Local Area Networks，WLAN)等通信网络通信。收发器43可以包括基带处理器的全部或部分，以及还可选择性地包括RF处理器。RF处理器用于收发RF信号，基带处理器则用于实现由RF信号转换的基带信号或即将转换为RF信号的基带信号的处理。
总线44，可以是工业标准体系结构(Industry Standard Architecture，ISA)总线、外部设备互连(Peripheral Component Interconnect，PCI)总线或扩展工业标准体系结构(Extended Industry Standard Architecture，EISA)总线等。该总线可以分为地址总线、数据总线、控制总线等。为便于表示，图10中仅用一条粗线表示，但并不表示仅有一根总线或一种类型的总线。
图10中示出的设备结构并不构成对接入网设备的限定，可以包括比图示更多或更少的部件，或者组合某些部件，或者不同的部件布置。
应理解，本申请实施例中的接入网设备可以是RAN设备，或者AN设备。
应理解，本申请实施例中一种通信方法的执行主体可以为源(或目标)接入网设备，也可以为应用于源(或目标)接入网设备中的芯片。本申请实施例对此不作限定。下述以一种通信方法的执行主体为源接入网设备和目标接入网设备为例。
如图11所示，本申请实施例提供一种通信方法，该方法包括：
S101、源接入网设备向目标接入网设备发送终端的第一数据包。
应理解，源接入网设备为切换前终端接入的接入网设备，目标接入网设备为源接入网设备为终端选择的切换后为终端提供服务的接入网设备。
其中，第一数据包可以包括在终端的切换过程中源接入网设备处理的终端的下行数据包。该终端的下行数据包可以是在终端的切换过程中源接入网设备从核心网接收到的发送给该终端的数据包，也可以是在终端的切换过程中源接入网设备待发送给该终端的数据包，还可以是在终端的切换过程中源接入网设备发送给该终端的数据包，还可以是源接入网设备对在切换过程中需要发送给终端的数据包进行复制得到的数据包(简称复制数据包)，不予限制。
此外，该第一数据包可以包括终端的一个或多个(两个或以上)下行数据包。
示例性地，当待发送给终端的数据包的数量为一个时，该第一数据包即为待发送给终端的数据包。当待发送给终端的数据包的数量为多个时，源接入网设备可以将该多个待发送给终端的数据包分批发送给目标接入网设备，此时，第一数据包可以为源接入网设备第一批发送给目标接入网设备的数据包，其中，第一数据包可以为由多个待发送给终端的数据包中的两个或两个以上的数据包重新封装而成的数据包；也可以为多个待发送给终端的数据包中的任一个数据包。例如，待发送给终端的数据包包括： 数据包1～数据包15。第一数据包可以为数据包1～数据包5。
示例1，源接入网设备可以为图1所示的系统中LTE eNB1，目标接入网设备可以为图1所示的系统中的LTE eNB2。或者源接入网设备可以为图2所示的系统中LTE eNB，目标接入网设备可以为图2所示的系统中的eLTE eNB。在这种情况下，源接入网设备可以通过X2接口将第一数据包发送给目标接入网设备。
示例2，源接入网设备可以为图2所示的系统中的eLTE eNB，目标接入网设备可以为图2所示的系统中的NR gNB。或者源接入网设备可以为图4所示的系统中gNB1，目标接入网设备可以为图4所示的系统中的gNB2。在这种情况下，源接入网设备可以通过Xn接口将第一数据包发送给目标接入网设备。
示例3，如果源接入网设备和目标接入网设备之间不存在Xn/X2接口，源接入网设备可以直接将第一数据包传输给目标接入网设备。例如，源接入网设备和目标接入网设备之间建立隧道。源接入网设备通过与目标接入网设备之间建立的隧道将第一数据包传输给目标接入网设备。或者，源接入网设备将第一数据包发送给源接入网设备对应的源UPF网元，源UPF网元发送给目标UPF网元，目标UPF网元再转发给目标接入网设备。如果源UPF网元和目标UPF为同一个UPF，则源UPF网元可以直接将第一数据包发送给目标接入网设备。
当然，源接入网设备还可以为如图9所示的gNB1中的CU或DU，目标接入网设备还可以为如图9所示的gNB2中的CU或DU。本申请实施例对此不作限定。
示例性的，本申请实施例中的终端的下行数据包可以从该源接入网设备对应的核心网获取。具体的获取过程可以参考现有技术中的描述，此处不再赘述。
示例性的，如图12所示，终端的下行数据包包括：缓存在源接入网设备缓冲区中的该终端的下行数据包(简称：缓存数据包)(例如，数据包2和数据包3)、源接入网设备从UPF网元接收到的该终端的新数据包(简称：新数据包)，以及该终端的复制数据包(参见前述描述)。例如，复制数据包可以为对数据包1进行复制得到的数据包。
示例性的，缓存数据包通常可以指层2数据包，该数据包已经封装PDCP头。新数据包为未封装PDCP头的数据包，例如可以为IP包。复制数据包主要是指已经通过源接入设备发送给终端的数据包，或者准备发送给终端的数据包。
应理解，当源接入网设备将一个数据包发送给终端之后，源接入网设备中除了该数据包的复制数据包外，将不具有该数据包。
可以理解的是，数据包1和复制数据包为相同的数据包。
S102、目标接入网设备接收来自源接入网设备的终端的第一数据包。
应理解，目标接入网设备在哪个接口上接收终端的第一数据包，可以结合源接入网设备和目标接入网设备所处的网络，此处不再赘述。例如，源接入网设备在Xn接口上向目标接入网设备发送第一数据包，则目标接入网设备可以在Xn接口上接收第一数据包。
S103、当源接入网设备确定目标接入网设备接收到第一数据包时，源接入网设备向终端发送第一消息。
其中，第一消息用于指示终端切换至目标接入网设备。
需要说明的是，S103可以通过如下过程替换：源接入网设备确定目标接入网设备接收到第一数据包，源接入网设备向终端发送第一消息。或者，S103可以替换为：当源接入网设备接收到来自目标接入网设备的第二消息时，源接入网设备向终端发送第一消息。或，在源接入网设备根据时延信息确定目标接入网设备接收到第一数据包。或者当源接入网设备接收到来自目标接入网设备的第二消息之后，源接入网设备向终端发送第一消息。
示例性的，第一消息可以为切换命令，该第一消息中至少携带目标接入网设备的标识信息。该目标接入网设备的标识信息用于识别目标接入网设备。
可选的，在一些实施例中，本申请实施例提供的方法还包括：
S104、终端接收来自源接入网设备的第一消息，并根据第一消息切换至目标接入网设备。
应理解，终端接收来自源接入网设备的第一消息，便可以从源接入网设备切换至目标接入网设备。
具体的，第一消息中可以携带目标小区的标识，终端接入目标小区，从而切换至目标接入网设备。目标小区为目标接入网设备中的一个小区。其中，目标小区的标识可以由目标接入网设备发送给源接入网设备，具体可以参考现有技术中的描述，不再赘述。
其中，第一消息可以为切换命令。
S105、当终端从源接入网设备成功切换至目标接入网设备时，目标接入网设备向终端发送第一数据包。
示例性的，S105可以通过以下方式替换：目标接入网设备确定终端从源接入网设备成功切换至目标接入网设备，目标接入网设备向终端发送第一数据包。
应理解，S105之后还可以包括：终端接收来自目标接入网设备的第一数据包。
需要说明的是，当步骤101中的第一数据包包括终端的多个下行数据包时，步骤105中向终端发送的第一数据包，可以分多次发送给终端，例如，将该多个数据包重新封装成至少两个下行数据包发送给终端，具体地，可以将该多个数据包拆分成上述多个下行数据包发送给终端；也可以一次发送给终端，不予限制。
本申请实施例中在源接入网设备向终端发送第一消息之前，源接入网设备需要将在切换过程中需要发送给终端的数据包发送给终端。这样终端在切换至目标接入网设备之前可以从源接入网设备处获取到切换过程中发送给终端的数据包，在终端切换至目标接入网设备以后，终端可以从目标接入网设备处获取发送给终端的数据包。即一方面，如果终端从源接入网设备处未正确接收到的某个数据包(例如，未正确解析数据包或者因为空口质量差未成功接收数据包等)的情况下，终端还可以从目标接入网设备处接收到的一份相同的数据包。另一方面，如果终端从源接入网设备处正确接收到的一份数据包，也从目标接入网设备处接收到的一份相同的数据包。此时终端可以根据数据包的SN，丢弃重复的数据包，即将具有相同SN中的数据包保留一个，或者终端如果确定已经存在某个SN，则可以丢弃新接收到的该SN的数据包。
本申请实施例提供的通信方法，由于在终端切换至目标接入网设备的过程(即源接入网设备向终端发送第一消息之前)中，源接入网设备依旧需要将第一数据包发送 给终端。如果在切换过程中由于空口的信号质量差，终端有可能未接收到第一数据包。因此，通过源接入网设备向目标接入网设备发送第一数据包，这样在源接入网设备在确定目标接入网设备接收到第一数据包时，向终端发送指示终端切换至目标接入网设备的第一消息。一方面可以使得目标接入网设备处具有第一数据包。另一方面，在确定目标接入网设备接收到第一数据包之后，再向终端发送第一消息，可以使得在终端从源接入网设备成功切换至目标接入网设备以后，由目标接入网设备向终端发送第一数据包。这样可以保证终端在切换过程中无法从源接入网设备处接收到第一数据包的情况下，还可以从目标接入网设备处获取到第一数据包，保证了数据传输的可靠性。此外，由于发送给目标接入网设备的数据包是在向终端发送切换命令之前，这样与现有技术中在向终端发送切换命令之后才向目标接入网设备发送终端的数据包相比，可以进一步降低时延。
为了保证终端接收到的数据包的可靠性，第一数据包包括复制数据包，在上述实施例的一种实施场景中，上述方法还可以包括：源接入网设备获得复制数据包；或者，当满足为终端切换接入网设备的条件时，源接入网设备获得复制数据包。
示例性的，源接入网设备获得复制数据包可以通过以下方式1或方式2具体实现：
方式1、源接入网设备对终端的数据包中满足预设条件的数据包进行复制，得到复制数据包。也即源接入网设备在切换过程中，源接入网设备确定数据包满足预设条件时，源接入网设备对满足预设条件的数据包进行复制，得到复制数据包。
需要指出的是，本申请各实施例中终端的数据包可以指的是步骤S101中终端的下行数据包，不予赘述。
本申请实施例中的源接入网设备具有预设条件。一种示例，该预设条件可以预先配置在源接入网设备内。另一种示例，该预设条件可以由核心网设备配置给源接入网设备。本申请实施例对此不作限定。
示例性的，满足预设条件的数据包包括以下情况中的至少一种：使用预设QoS流的数据包，预设分组数据单元(Packet data unit，PDU)会话上的数据包，丢包率小于或等于预设门限值的数据包，或者预设无线承载上的数据包。
可选的，满足预设条件的数据包还包括：使用预设业务类型的数据包、可靠性要求大于或等于第二预设门限值的数据包。此处的第二预设门限值用于与预设门限值进行区分。其中，丢包率小于或等于预设门限值也可以描述为“丢包率需求小于或等于预设门限值”。
该情况下，源接入网设备可以针对特定的数据包开启复制功能，以满足数据包对应的业务的QoS要求。该情况下，可以保证相应业务或数据包的QoS保障能力。例如，可以提升对指定终端的业务的数据传输的QoS保障能力。
以下对数据包满足预设条件的不同的情况分别进行介绍：
情况(1)、预设无线承载上的数据包(无线承载粒度)
其中，预设无线承载也可以为该终端具有的一个或多个无线承载(radio bearer，RB)中的至少一个无线承载。其中，RB可以为信令无线承载(signalling radio bearers，SRB)或数据无线承载(data radio bearers，DRB)。
该情况下，源接入网设备对承载在预设无线承载上的所有数据包都进行复制。其 中，源接入网设备可以根据数据包中携带的终端的标识和终端的无线承载的标识确定数据包是否为承载在预设无线承载上的数据包。源接入网设备还可以根据数据包中携带的GTP隧道的隧道端点标识(tunnel endpoint identifier，TEID)(或根据数据包中携带的通用分组无线服务隧道协议(general packet radio service tunneling protocol，GTP)隧道的TEID及源接入网设备的标识如IP地址)确定数据包是否为承载在预设无线承载上的数据包，或者，源接入网设备还可以通过终端的标识和GTP隧道的TEID确定数据包是否为承载在预设无线承载上的数据包。
示例性的，预设无线承载可以为对应可靠性要求较高的业务的无线承载，或者，预设无线承载可以为预设的某些无线承载。
示例性的，若终端的DRB1对应于可靠性要求较高的业务，则预设无线承载可以为DRB1。参见图1，若源接入网设备确定一个数据包1使用DRB1传输，则源接入网设备复制该数据包1。
情况(2)、预设分组数据单元PDU会话(Session)上的数据包(PDU会话粒度)
PDU会话：5G网络内，终端上建立的一组QoS流flow的组合，这些QoS flow具有相同的IP地址和数据网络名称(Data Network Name，DNN)。在终端和网络侧，通过IP地址和DNN来标识一个PDU会话。
每一PDU session具有一唯一标识，PDU session的唯一标识可以是以下几种之一：PDU会话标识，APN，用户面核心网设备的标识，用户面核心网设备的地址(例如，IP地址)，用户面核心网设备为终端分配的IP地址。
其中，预设分组数据单元PDU会话也可以为一个或多个PDU会话。该情况下，源接入网设备对承载在预设分组数据单元PDU会话上的所有数据包都进行复制。其中，源接入网设备可以根据数据包中携带的GTP隧道的TEID(或根据数据包中携带的GTP隧道的TEID及源接入网设备的标识如IP地址)确定数据包是否为预设分组数据单元PDU会话上的数据包。或者，源接入网设备还可以根据数据包中携带的终端的标识和GTP隧道的TEID确定数据包是否为预设分组数据单元PDU会话上的数据包。示例性的，TEID可以包括在数据包的GTP层协议头中。
应理解，一个终端可以具有多个PDU会话。例如，PDU会话1、PDU会话2和PDU会话3。如果预设分组数据单元PDU会话为PDU会话1和PDU会话2，则源接入网设备对承载在PDU会话1和PDU会话2上的所有数据包都进行复制。
情况(3)、预设服务质量QoS流的数据包(QoS流粒度)
QoS流是指一个PDU session内，具备相同QoS需求的数据流。可以是多个具有相同QoS需求的IP流。
该情况下，服务质量流标识(QoS Flow Identity，QFI)可以在GTP层的头信息中被解析从而获取到，或者，QoS流的QFI可以在服务数据适配(Service Data Adaption Protocal，SDAP)层被解析从而获取到。SDAP层表示业务适配层，SDAP层具备以下能力中的至少一种：为数据包添加能被接入网设备识别出的路由信息、基于所述路由信息执行路由选择、为数据包添加能被接入网设备识别出的与QoS需求相关的标识信息、为数据包执行在包括无线回传节点的多段链路上的QoS映射、为数据包添加数据包类型指示信息、向具有流量控制能力的节点发送流控反馈信息。
预设QoS流也可以为一个或多个QoS流。该情况下，源接入网设备对预设QoS流中的所有数据包都进行复制。其中，源接入网设备可以根据数据包中QFI确定数据包是否为预设QoS流。示例性的，QFI可以包括在数据包的GTP层协议头中。
例如，如果要求的QoS流和数据包中携带的QFI指示的服务质量流相同，或者位于要求的QoS流的范围内，则终端确定该数据包为预设QoS流的数据包。
在情况(2)和情况(3)中，源接入网设备可以根据业务的可靠性要求确定，业务的可靠性可以包括业务的时延、丢包率、抖动等。源接入网设备可以对可靠性要求较高的业务的数据包进行复制。该情况下，情况(2)中的预设PDU会话对应的业务即为可靠性要求较高的业务，情况(3)中的预设QoS流对应的业务即为可靠性要求较高的业务。
情况(4)、丢包率小于或等于预设门限值的数据包(数据包粒度)
该情况下，数据包中通常携带有用于指示丢包率的信息。源接入网设备确定接收到的数据包中用于指示丢包率的信息，指示该数据包的丢包率小于或等于预设门限值，则源接入网设备对该数据包进行复制。
情况(5)、数据包为预设业务类型的数据包
其中，预设业务类型的业务可以为可靠性要求较高的业务，例如，可以为超高可靠低时延通信(ultra-reliable low latency communication，URLLC)业务。该情况下，数据包可以为URLLC业务的数据包。
例如，数据包中可以携带用于指示该数据包的业务类型的信息，如果该数据包指示的业务类型为URLLC业务，则源接入网设备对该数据包进行复制。
情况(6)、数据包为可靠性要求大于或等于第二预设门限值的数据包
数据包的可靠性可以理解为数据包所属的业务的可靠性。第二预设门限值可以预先设置或由源接入网设备根据预设规则确定。
需要说明的是，数据包满足预设条件还可以包括上述多种情况(即数据包满足上述多种情况示出的条件时，数据包满足预设条件)，比如：数据包满足(1)(4)(5)中任意一种情况的条件的基础上还满足情况(2)(3)中的任意一种或多种情况的条件。
方式2、源接入网设备对终端的数据包进行复制，得到复制数据包。
上述方式2是以终端为粒度的实现方式。在该情况下，源接入网设备对该终端的数据包均进行复制。示例性的，源接入网设备可以根据数据包中携带的终端的标识识别该终端的数据包，并对识别出的数据包进行复制。
此外，核心网设备可以指示源接入网设备在切换过程中对该终端的数据包均进行复制。具体地，核心网设备可以指示源接入网设备在切换过程中对特定类型的终端的数据包进行复制。
上述主要描述了源接入网设备复制数据包的粒度，一方面，源接入网设备可以根据需要自行选择复制数据包的粒度。另一方面，源接入网设备可以根据业务的QoS需求或者根据会话的默认无线承载信息或者根据核心网的指示确定复制数据包的粒度。例如，如果核心网指示以终端粒度复制数据包，则源接入网设备将该终端的所有数据包进行复制得到复制数据包。例如，如果业务的QoS flow满足特定QoS需求，则源 接入网设备确定该QoS流作为预设QoS流。然后将该预设QoS流上的所有数据包进行复制得到复制数据包。
需要说明的是，源接入网设备可以在确定满足预设条件的数据包时，对满足预设条件的数据包统一复制。例如，满足预设条件的数据包包括：数据包1、数据包2，则源接入网设备复制数据包1，以及复制数据包2。或者，源接入网设备可以在确定满足预设条件的数据包时，对每发送一个满足预设条件的数据包，则对该满足预设条件的数据包进行复制。例如，源接入网设备发送数据包1时，则复制数据包1。源接入网设备发送数据包2时，复制数据包2。
复制数据包在未发送给目标接入网设备之前可以先缓存在源接入网设备中。
其中，终端的数据包可以包括对从核心网接收到的数据包进行复制的复制数据包，此时，复制数据包中不包括序列号(sequence number，SN)；也可以包括对源接入网设备发送给终端的数据包进行复制的复制数据包，此时复制数据包中包括SN。
可选地，在上述实施例的另一种实施场景中，为了提高源接入网设备确定目标接入网设备接收到第一数据包的准确性，源接入网设备可以通过以下方式确定目标接入网设备接收到第一数据包，如图13所示，上述方法还可以包括：
S106、目标接入网设备向源接入网设备发送第二消息，该第二消息用于指示目标接入网设备接收到第一数据包。
相应地，源接入网设备可以接收来自目标接入网设备的第二消息，进而执行步骤S103中的源接入网设备向终端发送第一消息。
其中，第二消息可以是数据接收确定指示(例如，User Data received indication)。
相应的，本申请实施例S103中源接入网设备确定目标接入网设备接收到第一数据包，可以通过以下方式具体实现：源接入网设备可以根据第二消息确定目标接入网设备接收到第一数据包。显然，此时步骤S103可以替换为：当源接入网设备接收到来自目标接入网设备的第二消息时，源接入网设备向终端发送第一消息。
另一种可能的实现方式，本申请实施例中源接入网设备确定目标接入网设备接收到数据包，还可以通过以下方式3实现：
方式3、源接入网设备根据时延信息，确定目标接入网设备接收到第一数据包。显然，此时步骤S103可以替换为：当源接入网设备根据时延信息确定目标接入网设备接收到第一数据包，源接入网设备向终端发送第一消息。
例如，源接入网设备在向目标接入网设备发送第一数据包时可以启动一个定时器，若该定时器超时，则确定目标接入网设备接收到第一数据包。
本申请实施例对时延信息的获取方式不做限定。
示例性的，一方面，该时延信息可以是预配置给终端的，或者源接入网设备可以根据第一数据包的QoS信息确定时延信息，或者源接入网设备在会话管理过程中从会话管理功能单元处获取时延信息。
示例性的，源接入网设备可以根据QoS参数中的5G QoS标识(5QI)信息确定核心网的传输时延，从而确定时延信息。
示例性的，会话管理过程可以指PDU会话建立流程或者PDU会话更新(也可以称为PDU会话修改)流程。
在一种可选的实施方式中，源接入网设备可以在确定将终端切换至目标接入网设备的情况下，便将终端的数据包发送给目标接入网设备，即源接入网设备可以在向目标接入网设备发送切换请求消息的过程中将终端的数据包发送给目标接入网设备。在这种情况下，如果目标接入网设备允许将终端切换至目标接入网设备，可以减少时延。
应理解，切换请求消息的内容可以参现有技术中的描述。
在另一种可选的实施方式中，源接入网设备确定目标接入网设备允许将终端切换至目标接入网设备的情况下，源接入网设备将终端的数据包发送给目标接入网设备。这样便于在得到目标接入网设备允许切换时，才向目标接入网设备发送给终端的数据包。避免因为目标接入网设备拒绝切换时导致的资源浪费。如图14所示，在S101之前，上述方法还可以包括：
S107、目标接入网设备向源接入网设备发送第一信息，该第一信息用于指示允许终端切换至目标接入网设备。
其中，第一信息可以携带在切换请求确认消息中，或者该第一信息为切换请求确认消息。
S108、源接入网设备接收来自目标接入网设备的第一信息。
示例性地，源接入网设备在向目标接入网设备发送切换请求消息之后，源接入网设备从目标接入网设备处接收到的用于指示允许切换的第一信息，源接入网设备即向目标接入网设备发送第一数据包。
为了进一步确定目标接入网设备允许终端切换至目标接入网设备，S101还可以由如下步骤替换：源接入网设备根据第一信息确定目标接入网设备允许终端切换至目标接入网设备，源接入网设备向目标接入网设备发送第一数据包。
在一种可选的实施方式中，在S101之前还包括如下过程：源接入网设备获取测量报告和无线资源管理信息。源接入网设备根据测量报告和无线资源管理信息确定满足为终端切换接入网设备的条件，则源接入网设备开启数据包复制功能，即源接入网设备激活源接入网设备的数据复制功能，也可以理解为源接入网设备执行上述复制数据包的步骤。
示例性的，测量报告可以由终端上报给源接入网设备。
例如，源接入网设备根据测量报告确定源接入网设备的信号质量或者电平低于预设门限，确定满足为终端切换接入网设备的条件。
此外，在源接入网设备确定目标接入网设备之后，源接入网设备可以向目标接入网设备发送切换请求消息，该切换请求消息用于请求将终端切换至目标接入网设备。如果目标接入网设备允许将终端切换至目标接入网设备，目标接入网设备向源接入网设备发送用于指示同意切换的消息(即上述第一信息)，这样源接入网设备便可以确定目标接入网设备允许将终端切换至目标接入网设备。
示例性的，该切换请求消息可以包括源接入网设备的小区无线网络临时鉴定(cell-Radio Network Temporary Identifier，C-RNTI)，目标小区标识，源小区的物理层标识，密钥参数等。具体的切换请求消息中还携带的其他内容可以参考现有技术中源接入网设备请求将终端切换至目标接入网设备过程中的切换请求消息。
应理解，如果源接入网设备和目标接入网设备之间存在Xn接口或者X2接口的情 况下，源接入网设备可以通过Xn接口或者X2接口向目标接入网设备发送切换请求消息。目标接入网设备也可以通过X2接口或Xn接口向源接入网设备发送用于指示同意切换的消息。例如，在图1中源接入网设备和目标接入网设备可以通过X2接口交互切换请求消息和用于指示同意切换的消息。在图4中源接入网设备和目标接入网设备可以通过Xn接口交互切换请求消息和用于指示同意切换的消息。
如果源接入网设备和目标接入网设备之间存在Xn接口或者X2接口的情况下，源接入网设备可以将切换请求消息发送给源接入网设备对应的移动管理网元1，然后通过移动管理网元1将该切换请求消息发送给目标接入网设备对应的移动管理网元2。再由移动管理网元2将切换请求消息发送给目标接入网设备。在目标接入网设备同意切换时，目标接入网设备通过移动管理网元2、移动管理网元1将用于指示同意切换的消息发送给源接入网设备。应理解，移动管理网元(例如，AMF网元或者MME)1和移动管理网元2可以为同一个移动管理网元。
示例性的，在图1所示的系统中以源接入网设备为LTE eNB1，目标接入网设备为LTE eNB2为例，LTE eNB1和LTE eNB2之间不具有X2接口的情况下，则LTE eNB1将切换请求消息发送给EPC，然后EPC通过S1接口将切换请求消息发送给LTE eNB2。反之，LTE eNB2同意切换时，LTE eNB2通过S1接口将用于指示同意切换的消息发送给EPC、EPC将用于指示同意切换的消息通过S1接口发送给LTE eNB1。
示例性的，在图4所示的系统中以源接入网设备为gNB1，目标接入网设备为gNB2为例，gNB1和gNB2之间不具有Xn接口的情况下，则gNB1将切换请求消息通过N2接口发送给NG-Core，然后NG-Core通过N2接口将切换请求消息发送给gNB2。反之，gNB2同意切换时，gNB2通过N2接口将用于指示同意切换的消息发送给NG-Core、NG-Core将用于指示同意切换的消息通过N2接口发送给gNB1。
如果源接入网设备和目标接入网设备属于不同的网络，且源接入网设备和目标接入网设备之间不具有接口的情况下，以源接入网设备为eNB，目标接入网设备为gNB为例，则eNB通过S1接口将切换请求消息发送给EPC，然后EPC通过与NG-Core之间的接口将切换请求消息发送给NG-Core，然后NG-Core通过N2接口发送给gNB。反之，gNB2同意切换时，gNB2通过N2接口将用于指示同意切换的消息发送给NG-Core、NG-Core将用于指示同意切换的消息通过接口发送给EPC。EPC将用于指示同意切换的消息通过S1接口发送给LTE eNB1。
应理解，本申请实施例中源接入网设备向目标接入网设备发送数据包的接口可以参考源接入网设备向目标接入网设备发送切换请求消息的接口。
可选地，在上述实施例的另一种实施场景中，源接入网设备将终端的数据包向目标接入网设备发送的过程中，还可以向目标接入网设备发送序列号SN状态信息。如图15所示，上述方法还可以包括：
S109、源接入网设备向目标接入网设备发送序列号SN状态信息。
其中，该SN状态信息用于目标接入网设备向终端发送数据包。SN状态信息具体可以包括：下行PDCPSN发送状态。比如，下行PDCP SN发送状态用于指示目标接入网设备需要分配的下一个新的PDCP SN号。
示例性的，该SN状态信息可以在源接入网设备向目标接入网设备请求切换的过 程中发送给目标接入网设备。例如，SN状态信息可以携带在切换请求消息中。这样目标接入网设备在接收到第一数据包之后，便可以根据SN状态信息设置数据包的SN。
应理解，本申请实施例中源接入网设备向目标接入网设备发送SN状态信息，可以由如下情况。一种情况、SN状态信息用于指示源接入网设备发送给终端的数据包的SN。另一种情况用于指示目标接入网设备发给终端应该携带的SN。
S110、目标接入网设备接收来自源接入网设备的SN状态信息。
由于源接入网设备发送给目标接入网设备的终端的数据包中除了设置SN的数据包之外，还可能包括未携带SN的数据包，因此，如果目标接入网设备从源接入网设备接收到的未携带SN的数据包，则在S110之后，上述方法还可以包括S111：
S111、目标接入网设备根据SN状态信息，处理从源接入网设备处接收到的未携带SN的数据包，得到第二数据包，以及向终端发送第二数据包。
其中，第二数据包的SN可以根据所述SN状态信息来确定。
应理解，一方面，未携带SN的数据包可以为第一数据包中的数据包，例如IP包，或者以太包，或者其他类型的数据包。
例如，第一数据包包括：数据包1、数据包2、数据包3，其中，源接入网设备已为数据包1和数据包2设置SN，即数据包1和数据包2携带SN。而数据包3未携带SN，则目标接入网设备在接收到的数据包3时，可以根据SN状态信息确定数据包3的SN。
另一方面，未携带SN的数据包还可以是终端的数据包中除第一数据包之外的数据包。例如，终端的数据包包括第一数据包和第二数据包，其中，第一数据包携带SN，而第二数据包未携带SN，则根据SN状态信息确定第二数据包的SN。
应理解，在S111之后还可以包括：终端接收目标接入网设备发送的第二数据包。
如图16所示，图16示出了本申请实施例提供的另一种通信方法，为了便于描述，下文以源接入网设备为S-RAN设备，目标接入网设备为T-RAN设备，以S-RAN设备和T-RAN设备之间具有Xn接口为例进行描述，具体如下所述。
步骤201、S-RAN设备从AMF网元处获取终端上下文。
具体的，S-RAN设备从AMF网元处获取移动控制信息(Mobility Control Information)。
其中，该移动控制信息可以包括终端上下文。
其中，该终端上下文可以包括漫游的接入限制信息。
其中，该接入限制信息可以在连接建立或者跟踪区(Tracking Area，TA)更新过程中提供，该接入限制信息可以包括可用的频段信息。
应理解，在步骤201之前，终端可以通过S-RAN设备与核心网建立连接，且终端与核心网之间可以通过已经建立的连接传输数据。例如，终端通过S-RAN设备向核心网发送上行数据包，或者终端通过S-RAN设备接收核心网发送的下行数据包。
步骤202、S-RAN设备为终端配置测量配置参数。
其中，S-RAN设备可以是5G的gNB、NR或其他RAN设备，本申请实施例对此不作限定。
步骤203、终端根据测量配置参数向S-RAN设备发送测量报告(Measurement  Reports)。
其中，该测量报告用于指示终端测量的信号质量，可以包括一个或多个RAN设备的测量报告。
示例性地，在终端通过S-RAN接入第一网络的场景中，S-RAN设备为终端的服务小区所属的RAN设备。终端会周期性测量终端的服务小区的信号质量和终端的邻小区的信号质量。终端可以周期性的向S-RAN设备发送测量报告，该测量报告包括：服务小区所属的RAN设备的信号质量和终端的邻小区所属的RAN的信号质量。也可以由事件触发向S-RAN设备发送测量报告，还可以在终端所属的TA发生变化后，向S-RAN设备发送测量报告。S-RAN设备根据终端上报的测量报告判断是否为终端切换RAN设备。
本申请实施例中的第一网络为EPC网或者NG-Core网。
其中，信号质量可以包括参考信号接收功率(Reference Signal Receiving Power，RSRP)。或者，信号质量可以包括参考信号接收质量(Reference Signal Receiving Quality，RSRQ)。或者，信号质量可以包括RSRP和RSRQ。
当然，凡是可以用来体现终端接收服务小区所属的RAN设备的信号质量和终端的邻小区所属的RAN的信号质量的参数，均可以作为终端接收服务小区所属的RAN设备的信号质量和终端的邻小区所属的RAN的信号质量，本申请实施例对此不作限定。
一种示例，终端确定服务小区的信号质量小于或等于第一预设阈值，或者邻小区的信号质量大于或等于第二预设阈值时，终端向S-RAN设备发送测量报告。另一种示例，终端按照预设周期在预设周期将获取到的服务小区的信号质量或者邻小区的信号质量作为测量报告发送给S-RAN设备。又一种示例，终端可以在接收到S-RAN设备发送的测量指示，该测量指示用于指示终端测量服务小区的信号质量或者邻小区的信号质量。这样终端在接到测量指示之后便可以根据测量配置参数测量服务小区的信号质量或者邻小区的信号质量。进一步可选的，该测量指示还可以用于指示终端按照预设周期周期性的向S-RAN设备发送测量报告，以及在服务小区的信号质量小于或等于第一预设阈值，或者邻小区的信号质量大于或等于第二预设阈值时，终端向S-RAN设备发送测量报告。
本申请实施例对第一预设阈值、第二预设阈值以及预设周期不作限定，可以根据需求进行设置。
步骤204、S-RAN设备基于测量报告和无线资源管理(Radio Resource Management，RRM)信息确定执行切换(Handover decision)，并激活(或者开启)数据包复制功能。
其中，数据包复制功能可以指的是S-RAN设备复制S-RAN设备在切换过程中需要发送给终端的数据包。此外，激活数据包复制功能为可选动作，可以不执行。
应理解，S-RAN设备中可能存在如下类型的用户面数据：缓存在S-RAN设备的缓冲区中需要发送给终端的数据包、从空口新接收到的需要发送给终端的数据包以及第一数据包。其中，第一数据包为在切换过程中需要发送给终端的数据包。由于在204中S-RAN设备仅是确定需要为终端切换RAN设备，但是此时终端并未接入T-RAN设备中。因此从S-RAN设备确定需要为终端切换RAN设备到S-RAN设备向终端发送切 换命令之前的这段时间内，S-RAN设备需要将发送给终端的数据包发送给终端，因此，可以将S-RAN设备确定需要为终端切换RAN设备到S-RAN设备向终端发送切换命令之前的这段时间定义为切换过程中，将在切换过程中S-RAN设备需要向终端发送数据包定义为第一数据包。
由于S-RAN设备确定发起切换之后空口的通信质量可能变得很差，因此无法保证在终端切换到T-RAN设备之前接收到的数据包的可靠性。为了保证在切换过程中终端接收到的数据包的可靠性，本申请实施例中S-RAN设备可以对第一数据包进行复制，以得到复制数据包。应理解第一数据包和复制数据包为相同的数据包。
例如，S-RAN设备确定发起切换时，需要向终端发送数据包1、数据包2，则S-RAN设备可以对数据包1进行复制得到数据包1’，以及对数据包2进行复制得到数据包2’。然后将数据包1和数据包2发送给终端。
示例性的，RRM信息中包括一个或者多个邻小区所属的RAN的信息，这样当S-RAN设备根据测量报告确定服务小区的信号质量不满足需要时，根据无线资源管理信息确定一个RAN设备作为终端切换的T-RAN设备。具体的，S-RAN设备可以根据一个或者多个邻小区的信号质量选择一个信号质量大于或等于第二预设阈值的邻小区所属的RAN设备作为终端切换的T-RAN设备。
步骤205、S-RAN设备向T-RAN设备发送切换请求消息(Handover Request message)。
其中，该切换请求消息可以用于请求将终端切换至T-RAN设备。
该切换请求消息包含但不限于以下信息：切换原因，用于指示此次切换的原因，例如无线网络层原因(由于信号原因触发的切换，基于资源的优化等)。目标小区标识，用于唯一指示目标小区的标识。切换限制列表，包含服务PLMN，等效PLMN，禁止的服务区等。终端对应的临时标识，用于CN设备查找保存的终端的上下文(UE context)。终端关联的核心网控制功能实体标识。终端选择的一个或者多个或者全部网络切片分别对应的网络切片标识。终端选择的一个或者多个或者全部网络切片分别对应的需要建立的无线承载信息，例如无线承载标识，无线承载级别的QoS参数，隧道终结点，无线承载对应的用户面安全信息。终端选择的一个或者多个或者全部网络切片分别对应的需要建立的会话信息，例如会话标识，会话级别的QoS参数，隧道终结点，会话对应的用户面安全信息。终端选择的一个或者多个或者全部网络切片分别对应的需要建立的流信息，例如流标识，流级别的QoS参数，隧道终结点，流对应的用户面安全信息。无线承载信息，例如无线承载标识，无线承载级别的QoS参数，隧道终结点，无线承载对应的用户面安全信息。其他需要建立的会话信息，例如会话标识，会话级别的QoS参数，隧道终结点，会话对应的用户面安全信息。其他需要建立的流信息，例如流标识，流级别的QoS参数，隧道终结点，流对应的用户面安全信息。该终端设备的上下文信息，例如终端设备签约的一个或者多个或者全部网络切片对应的网络切片标识等。
示例性的，UE context包括移动性管理上下文(Mobility Management Context，MM Context)和承载上下文(Bearer Context),网络切片指示信息，其中，MM Context包括临时标识GUTI、非接入层(Non-Access Stratum，NAS)密钥、安全算法等信息， Bearer Context包括承载的标识、QoS等信息。
可选的，Handover Request message中包括下行SN状态(DL SN Status)信息。
具体的，S-RAN设备通过与T-RAN设备之间的接口(如Xn接口)向T-RAN设备发送切换请求(Handover Required)消息。
步骤206、T-RAN设备执行准入控制(Admission Control)。
T-RAN设备向执行准入控制表明该T-RAN设备已经准备好了资源，做好切换准备。在该步骤206中，该T-RAN设备根据自身对终端在S-RAN设备所通信的网络切片的流/会话/无线承载的支持能力、资源情况以及重映射策略信息等对终端进行准入控制。
例如，如果T-RAN设备确定可以满足终端在S-RAN设备所通信的网络切片的流/会话/无线承载的支持能力、资源情况以及重映射策略信息等信息，则T-RAN设备执行准入控制(Admission Control)，否则T-RAN设备向S-RAN设备发送拒绝将终端切换至T-RAN设备的指示信息。例如，如果T-RAN设备确定可以满足终端所需要的无线资源要求，则T-RAN设备对终端进行准入控制。
在一种情况下，该T-RAN设备不支持该终端在S-RAN设备所通信的至少一个网络切片的至少一个流/会话/无线承载但有相关网络切片支持的能力，则该T-RAN设备可以向CN请求为该终端在S-RAN设备所通信的至少一个网络切片的至少一个流/会话/无线承载重映射到该T-RAN设备所支持的网络切片上。例如，该T-RAN设备通过在步骤205接收的切换请求消息中携带的网络切片指示信息判断该T-RAN设备不支持该终端在S-RAN设备所通信的至少一个网络切片，但是通过在步骤205接收的无线承载上下文以及当前的资源使用状况等确定可以满足该终端当前通信的流/会话/无线承载的QoS需求，则T-RAN设备认为有该终端的流/会话/无线承载所需的网络切片的支持能力。
另一种可能的情况是，该T-RAN设备不能明确是否支持该终端在S-RAN设备所通信的网络切片，则该T-RAN设备可以向CN请求在该T-RAN设备不支持该终端在S-RAN设备所通信的至少一个网络切片的情况下为该终端在S-RAN设备所通信的至少一个网络切片的至少一个流/会话/无线承载重映射到该T-RAN设备所支持的网络切片上。例如，T-RAN设备通过在步骤205接收的切换请求消息中携带的网络切片指示信息不能判断能否支持该终端在S-RAN设备所通信的至少一个网络切片，但是通过在步骤205接收的无线承载上下文以及当前的资源使用状况等确定可以满足该终端当前通信流/会话/无线承载的QoS需求，则T-RAN设备认为有相关网络切片的支持能力。
另一种可能的情况是，该T-RAN设备不支持该终端在S-RAN设备所通信的至少一个网络切片的至少一个流/会话/无线承载，但是T-RAN设备根据从步骤205接收的网络切片重映射策略信息可以将该流/会话/无线承载重映射到该T-RAN设备所支持的网络切片，则该T-RAN设备可以向CN请求为该终端在S-RAN设备所通信的至少一个网络切片的至少一个流/会话/无线承载重映射到该T-RAN设备选择的所支持的网络切片上。
步骤207、T-RAN设备向S-RAN设备发送切换请求确认消息(Handover Request Acknowledge message)。
其中，切换请求确认消息可以用于指示T-RAN设备允许将终端切换至T-RAN设备。
示例性的，切换请求确认消息可以为上述实施例中的第一信息。
具体的，T-RAN设备可以在执行准入控制时，执行步骤207。
步骤208、在接收到T-RAN设备发送的切换请求确认消息的情况下，S-RAN设备开始向T-RAN设备发送用户面数据。
其中，该用户面数据至少包括复制数据包，以使得T-RAN设备可以接收来自S-RAN设备的终端的用户面数据。
示例性的，步骤208中的用户面数据可以为上述实施例中的第一数据包。
应理解，208中S-RAN设备向T-RAN设备发送的用户面数据还包括缓存在S-RAN设备的缓冲区中需要发送给终端的数据包，或新接收到的需要发送给终端的数据包。
例如，缓存在S-RAN设备的缓冲区中需要发送给终端的数据包为数据包21、从空口新接收到的需要发送给终端的数据包为数据包22，在切换过程中需要向终端发送数据包为数据包1、数据包2，则S-RAN设备可以在步骤208中向T-RAN设备发送的用户面数据包括：数据包21、数据包22、数据包1’以及数据包2’。
应理解，在S-RAN设备接收到切换请求确认消息时，S-RAN设备不仅向终端发送用户面数据，还向T-RAN设备发送用户面数据。
应理解，作为一种可选的实现方式，T-RAN设备接收到终端的用户面数据时，T-RAN设备向S-RAN设备发送数据接收确定指示，以使得S-RAN设备接收来自T-RAN设备的数据接收确定指示，从而确定T-RAN设备接收到用户面数据。
步骤209、当S-RAN设备确定T-RAN设备接收到用户面数据时，S-RAN设备向终端发送切换命令。
其中，该切换命令用于指示终端切换至T-RAN设备。例如，该切换命令中可以携带目标小区的标识或者目标小区所属的T-RAN设备的标识。
示例性的，切换命令可以为上述实施例中的第一消息。
具体的，步骤209中S-RAN设备确定T-RAN设备接收到用户面数据的方式可以参考上述实施例，本申请实施例在此不再赘述。
步骤210、终端根据切换命令接入T-RAN设备。
步骤210的具体实现方式可以参考现有技术中的描述，此处不再赘述。
步骤211、T-RAN设备向终端发送用户面数据。
其中，该用户面数据可以包括复制数据包。
应理解，步骤211中的用户面数据可以参见上述实施例中的第一数据包，不再赘述。
应理解，步骤211中T-RAN设备向终端发送的数据包包括复制数据包、以及处理后的缓存在S-RAN设备的缓冲区中需要发送给终端的数据包以及处理后的从空口新接收到的需要发送给终端的数据包。
应理解，当终端从S-RAN设备成功切换至T-RAN设备后，T-RAN设备便可以向终端发送用户面数据，此时，如果终端有上行数据包，也可以通过T-RAN设备发送给UPF网元。由于此时网络侧并不知道终端切换至T-RAN设备，因此为了使得网络侧发 送的下行数据包可以通过终端接入网的T-RAN设备发送给终端，本申请实施例提供的方法还可以包括下述步骤：
步骤212、T-RAN设备向AMF网元发送路径切换请求(path switch Request)。
步骤213、AMF网元与核心网之间执行路径切换流程。
具体的AMF网元与核心网之间执行路径切换流程可以参考现有技术中的描述。通过路径切换流程，UPF网元便可以确定将终端的下行数据包发送给T-RAN设备。
步骤214、AMF网元向T-RAN设备发送路径切换请求确认消息。
可以理解的是，经过步骤X12-步骤X14之后，AMF网元便可以确认为终端服务的RAN设备为T-RAN设备，也即AMF网元后续可以通过T-RAN设备与该终端通信。
步骤215、T-RAN设备在接收到路径切换请求确认消息之后，向S-RAN设备发送终端上下文释放(UE context release)消息。
应理解，S-RAN设备在接收到终端上下文释放消息之后，释放终端的上下文。
本申请实施例通过在将终端切换至T-RAN设备之前，由S-RAN设备将终端的用户面数据发送给T-RAN设备，然后在切换过程中S-RAN设备向终端依旧发送需要向终端发送终端的用户面数据。在终端从S-RAN设备成功切换至T-RAN设备之后，再由T-RAN设备向终端发送终端的用户面数据。即在切换过程中终端可以分别从S-RAN设备和T-RAN设备处获取两份相同的终端的用户面数据，进而保证切换过程中数据包的传输可靠性。此外，通过将终端切换至T-RAN设备之前，由S-RAN设备将终端的用户面数据发送给T-RAN设备可以降低切换的传输时延。
图16以T-RAN设备和S-RAN设备属于同一个AMF网元为例，在实际过程中，S-RAN设备和T-RAN设备可以属于不同的AMF网元。
综上，图16中包括：切换准备阶段(Handover Preparation)(例如，步骤201-步骤207)、切换执行阶段(Handover Execution)(例如，步骤208-步骤211)以及切换完成阶段(Handover Completion)(例如，步骤212-步骤215)。
由图17所示，图17示出了本申请实施例提供的一种通信方法。为了便于描述，下文以源接入网设备为S-RAN设备，目标接入网设备为T-RAN设备，以S-RAN设备和T-RAN设备之间不具有Xn接口，S-RAN设备向S-AMF发起切换流程(可以称为N2的切换流程)为例进行描述。N2的切换流程主要包括切换准备阶段和切换执行阶段。基于N2的切换流程包括S-RAN设备和T-RAN设备的AMF网元相同，和S-RAN设备和T-RAN设备的AMF网元不相同的场景。下述图17以S-RAN设备和T-RAN设备的AMF网元不相同的场景(例如，S-RAN设备对应S-AMF网元，T-RAN设备对应T-AMF网元)为例。具体如下所述。
步骤301、S-RAN设备确定发起N2的切换流程，并复制切换过程中终端的数据包。
应理解，在步骤301之前终端通过S-RAN设备与源用户面(S-UPF)网元之间建立连接(例如，PDU会话)。终端可以通过S-RAN设备向S-UPF网元发送上行(Uplink，UL)用户面数据。S-UPF网元可以通过S-RAN设备向终端发送下行(Downlink，DL)用户面数据。
步骤301中S-RAN设备复制S-RAN设备在切换过程中需要发送给终端的数据包 的过程可以参考上述步骤204，此处不再赘述。
步骤302、S-RAN设备向S-AMF网元发送切换请求消息。
其中，该切换请求消息中可以包括T-RAN设备的标识，源到目标容器(target to source transparent container)，会话管理(Session Management，SM)N2信息列表，PDU会话标识，系统内部切换指示。
其中，SM N2信息列表包括直接转发路径是否可用指示。系统内部切换指示用于指示该切换为5G内部的切换。
示例性的，直接转发路径可以指S-RAN设备与T-RAN设备之间的路径，也即从S-RAN设备到T-RAN设备之间所经过的网元。
其中，源到目标容器包括T-RAN使用的RAN信息，该源到目标容器中所携带的信息核心网不感知，即对核心网节点透传。
需要说明的是，target to source transparent container指S-RAN设备发送给T-RAN设备的一个容器，该容器中的具体内容在中间的网元不进行识别和处理，可以直接传给T-RAN设备，T-RAN设备在接收到源到目标容器后可以解析里面的内容。
可选的，该源到目标容器中包括SN状态信息，T-RAN设备可以根据该SN状态信息设置数据包的SN。
其中，S-AMF网元为S-RAN设备连接的AMF网元。
步骤303、若S-AMF网元不能为终端服务，则S-AMF网元为终端选择一个T-AMF网元。
示例性的，S-AMF网元根据T-RAN设备的标识，选择与T-RAN设备连接的AMF网元作为T-AMF网元。
示例性的，T-RAN设备的标识用于识别T-RAN设备。
例如，S-AMF网元根据T-RAN设备的标识确定T-RAN设备不由S-AMF网元管理，则S-AMF网元确定不能为终端服务。
步骤304、S-AMF网元向T-AMF网元发送建立终端上下文连接的请求(Namf_Communication_CreatUEContext Request)消息。
示例性的，该Namf_Communication_CreatUEContext Request消息中包括N2信息，终端上下文信息。
其中，N2信息包括T-RAN设备的标识，包括SN状态的源到目标容器，SM N2信息列表，PDU会话标识，服务区限制中的一个或者多个。
示例性的，一个PDU会话对应一个SM N2信息列表，该SM N2信息列表是发送给SMF网元的。
示例性的，终端上下文包括永久身份标识(subscriber permanent identifier，SUPI)，接入类型对应的允许的网络切片选择辅助信息(network slice selection assistant identifier，NSSAI)、PDU会话标识、终端的对应的SMF网元的信息以及单个网络切片选择辅助信息(Single network slice selection assistant identifier，S-NSSAI)，PCF网元标识和数据网络名称(data network name，DNN)。
步骤305、T-AMF网元向SMF网元发送更新PDU会话上下文的请求(Nsmf_PDUSession_UpdateSMContext Request)消息。
其中，该Nsmf_PDUSession_UpdateSMContext Request消息中可以包括SM N2信息列表。
示例性的，PDU会话上下文：包括该PDU会话使用的IP地址，接入点名字(Access Point Name，APN)，SMF网元及UPF网元地址，以及每个QoS流的上下文信息。
其中，步骤305之前还可以包括T-AMF网元根据终端上下文中携带的SMF信息确定步骤S305中的SMF网元。
步骤306、基于T-RAN设备的标识，SMF网元确定是否允许N2切换。
示例性的，如果SMF确定终端的会话业务不能在T-RAN设备的标识所指示的T-RAN设备的目标小区进行传输时，则不允许N2切换。例如，有些业务只能在特定的区域才能访问，如校园网，离开校园便不能访问。
进一步的，SMF网元可以检测UPF网元是否可以为终端提供服务。例如，如果SMF网元确定终端移出S-UPF网元的服务区，SMF网元为终端选择一个T-UPF网元。如果SMF网元选择了一个T-UPF网元，则执行步骤307。
步骤307、SMF网元向T-UPF网元发送N4会话建立请求(Session establish request)，以使得T-UPF网元可以接收N4会话建立请求。
其中，该N4会话建立请求可以用于建立用户面连接，该N4会话建立请求中可以携带用户面的隧道信息。
应理解，T-UPF网元还可以向SMF网元发送N4会话建立响应。
步骤308、SMF网元向T-AMF网元发送PDU会话上下文更新响应(Nsmf_PDUSession_UpdateSMContext Response)消息。
示例性地，如果SMF网元接受PDU会话切换，则Nsmf_PDUSession_UpdateSMContext Response消息中包括N3IP地址和上行(uplink，UL)CN隧道标识和QoS参数。如果SMF网元不接受PDU会话切换，则Nsmf_PDUSession_UpdateSMContext Response消息中包括一个不接受的原因值。
步骤309、T-AMF网元接收来自SMF网元的Nsmf_PDUSession_UpdateSMContext Response消息。
示例性地，如果T-AMF网元确定执行N2切换流程则执行步骤310。
例如，当T-AMF网元接收到SMF网元发送的Nsmf_PDUSession_UpdateSMContext Response消息，如果Nsmf_PDUSession_UpdateSMContext Response消息指示接受PDU会话切换，T-AMF网元确定执行N2切换流程。或者T-AMF网元确定最大等待时间超期，T-AMF网元确定执行N2切换流程。
步骤310、T-AMF网元向T-RAN设备发送切换请求消息。
其中，切换请求消息中可以包括N2 MM信息，N2会话管理(Session Management，SM)信息列表，源到目标容器，服务区限制，或不接受的PDU会话列表中至少一种，其中，源到目标容器中包括SN状态信息。
例如，N2 MM信息包含安全上下文等。
示例性的，不接受的PDU会话列表中携带切换失败的PDU会话的标识。
步骤311、T-RAN设备向T-AMF网元发送切换请求确认消息。
其中，切换请求确认消息中可以包括目标到源的容器，N2 SM响应列表，失败的 PDU会话列表，或T-RAN SM N3传输信息列表中至少一种。
示例性的，目标到源的容器中携带切换成功的QoS flow信息。
步骤311中的切换请求确认消息即为上述实施例中的第一信息。
其中，目标到源的容器指T-RAN设备发送给S-RAN设备的一个容器，该容器中的具体内容在中间的网元不进行识别和处理，可以直接传给S-RAN设备，S-RAN设备在接收到目标到源的容器后可以解析里面的内容。
示例性的，目标到源的容器可以包括安全上下文，QoS信息，目标小区标识。
步骤312、T-AMF网元向SMF网元发送Nsmf_PDUSession_UpdateSMContext Request消息。以使得SMF网元接收来自T-AMF网元的Nsmf_PDUSession_UpdateSMContext Request消息。
其中，Nsmf_PDUSession_UpdateSMContext Request消息中包括PDU会话标识，N2 SM响应，T-RAN SM N3转发信息列表。
对于每一个N2 SM响应，T-AMF网元向SMF网元发送N2 SM响应；如果没有T-UPF网元，则SMF网元存储N3隧道信息。
示例性的，N3隧道信息包含隧道标识和隧道地址。
应理解，如果SMF网元在执行步骤306时，选择了T-UPF网元，则SMF网元执行步骤313。
步骤313、SMF网元向T-UPF网元发送N4会话修改请求(N4 session modify Request)，N4会话修改请求中包括T-RAN SM N3转发信息列表，可选分配DL转发隧道的指示。
示例性的，T-RAN SM N3转发信息列表包含N3地址，N3的隧道标识。
步骤314、UPF网元向SMF网元发送的N4会话修改响应(N4 session modify Response)消息。
其中，N4会话修改响应消息中可以包括SM N3转发信息列表。
步骤315、SMF网元向S-UPF网元发送N4会话修改请求。
其中，N4会话修改请求中可以包括T-RAN SM N3转发信息列表或者T-UPF SMN3转发信息列表，间接转发的DL转发隧道指示。
步骤316、S-UPF网元向SMF网元发送N4会话修改响应，N4会话修改响应中包括S-UPF SM N3转发信息列表。
步骤317、SMF网元向T-AMF网元发送包括N2 SM信息列表的Nsmf_PDUSession_UpdateSMContext Response。
步骤318、T-AMF网元向S-AMF网元发送Namf_Communication_CreateUEContext Response。
其中，该响应中可以包括N2信息，PDU会话建立失败列表，或N2 SM信息列表中至少一种。
步骤319、S-AMF网元向S-RAN设备发送切换命令。
其中，切换命令中包括目标到源的容器，和/或N2 SM信息。
可选的，该切换命令中还可以包括失败的PDU会话列表。
步骤320、当S-RAN设备接收到T-RAN设备发送的切换请求确认消息时，S-RAN 设备开始向T-RAN设备发送终端的数据包。
其中，终端的数据包可以包括复制数据包。
示例性的，切换请求确认消息可以为上述实施例中的第一信息。
可选的，T-RAN设备还可以向S-RAN设备发送数据接收确定指示(例如，上述实施例中的第二消息)。
步骤321、S-RAN设备确定T-RAN设备接收到终端的数据包时，S-RAN设备向终端发送切换命令(Handover Command)。
其中，切换命令可以包括终端的容器。
示例性的，步骤321中的切换命令即为上述实施例中的第一消息。
示例性的，该终端的容器中包括目标小区的标识。
步骤322、终端根据切换命令同步到目标小区。
步骤323、T-RAN设备向终端发送切换确认消息。
其中，该切换确认消息可以用于表示切换成功。
应理解，经过步骤323之后，T-RAN设备便可以将从S-RAN设备处获取到的终端的数据包发送给终端。
步骤324、T-RAN设备向T-AMF网元发送切换通知。
其中，该切换通知可以用于表示切换成功。
步骤325、T-AMF网元向S-AMF网元发送N2通信信息通知(Namf_Communication_N2InfoNotify)。
步骤326、S-AMF网元向T-AMF网元发送Namf_Communication_N2InfoNotify。
步骤327、S-AMF网元向SMF网元发送释放PDU会话上下文的(Nsmf_PDUSession_ReleaseSMContext)请求。
其中，Nsmf_PDUSession_ReleaseSMContext请求中可以包括SUPI和PDU会话标识。
步骤328、T-AMF网元向SMF网元发送Nsmf_PDUSession_UpdateSMContext请求。
其中，Nsmf_PDUSession_UpdateSMContext请求中可以包括切换完成指示。
如果SMF网元选择了T-UPF网元，则本申请实施例提供的方法还可以包括：
步骤329、SMF网元向T-UPF网元发送N4会话修改请求。
步骤330、T-UPF网元向SMF网元发送N4会话修改响应。
如果SMF网元未选择T-UPF网元，则本申请实施例提供的方法还可以包括：
步骤331、SMF网元向S-UPF网元发送N4会话修改请求。
步骤332、S-UPF网元向SMF网元发送N4会话修改响应。
步骤333、SMF网元向UPF(PSA)发送N4会话修改请求。
步骤334、S-UPF网元向SMF发送N4会话修改响应。
至此，网络侧发送给终端的下行用户面数据，通过UPF(PSA)发送给T-UPF网元，再由T-UPF网元发送给T-RAN设备，然后由T-RAN设备发送给终端。
最终，SMF网元向T-AMF网元发送包含PDU会话标识的Nsmf_PDUSession_UpdateSMContext响应。终端发起移动注册更新流程。SMF网元向 S-UPF网元发送N4会话连接释放请求。S-UPF网元向SMF网元发送N4会话释放响应。AMF网元向S-RAN设备发送终端上下文释放命令。S-RAN设备向AMF网元发送终端上下文释放完成。
上述主要从各个网元之间交互的角度对本申请实施例的方案进行了介绍。可以理解的是，各个网元，例如通信装置等为了实现上述功能，其包含了执行各个功能相应的硬件结构和/或软件模块。本领域技术人员应该很容易意识到，结合本文中所公开的实施例描述的各示例的单元及算法步骤，本申请能够以硬件或硬件和计算机软件的结合形式来实现。某个功能究竟以硬件还是计算机软件驱动硬件的方式来执行，取决于技术方案的特定应用和设计约束条件。专业技术人员可以对每个特定的应用来使用不同方法来实现所描述的功能，但是这种实现不应认为超出本申请的范围。
本申请实施例可以根据上述方法示例对通信装置进行功能单元的划分，例如，可以对应各个功能划分各个功能单元，也可以将两个或两个以上的功能集成在一个处理单元中。上述集成的单元既可以采用硬件的形式实现，也可以采用软件功能单元的形式实现。需要说明的是，本申请实施例中对单元的划分是示意性的，仅仅为一种逻辑功能划分，实际实现时可以有另外的划分方式。
下面以采用对应各个功能划分各个功能模块为例进行说明：
如图18所示，图18示出了本申请实施例提供的通信装置的结构示意图，该通信装置可以是本申请实施例中的源接入网设备，也可以为应用于源接入网设备中的芯片，该通信装置可以用于执行上述各方法实施例中源接入网设备，或S-RAN设备的动作。
该通信装置包括：发送单元101和处理单元102。
其中，发送单元101用于支持该通信装置执行上述实施例中的S101、S103。
处理单元102用于支持该通信装置执行上述实施例中确定源接入网设备接收到第一数据包的步骤。
可选的，发送单元101还用于支持该通信装置执行上述实施例中的S109。
可选的，该通信装置还可以包括：接收单元103，用于支持该通信装置执行上述实施例中的S108。
上述方法实施例涉及的各步骤的所有相关内容均可以援引到对应功能模块的功能描述，在此不再赘述。
在采用硬件实现的基础上，本申请中的接收单元103、发送单元101可以为源接入网设备的通信接口或通信接口，或者应用于源接入网设备中的芯片的通信接口或通信接口，处理单元102可以集成在源接入网设备的处理器上或者应用于源接入网设备中的芯片的处理器上。
在采用集成的单元的情况下，图19示出了上述实施例中所涉及的通信装置的一种可能的逻辑结构示意图。该通信装置可以为源接入网设备或者应用于源接入网设备中的芯片，可以用于执行上述各方法实施例中源接入网设备，或S-RAN设备的动作。该通信装置包括：处理模块112和通信模块113。
其中，处理模块112用于对通信装置的动作进行控制管理，例如，处理模块112用于执行在通信装置侧进行消息或数据处理的步骤，例如，支持通信装置执行上述实施例中的S103中确定源接入网设备接收到第一数据包的步骤。通信模块113用于支持 通信装置执行上述实施例中的S101、S103、S108。可选的，通信模块113还用于支持通信装置执行上述实施例中的S109。和/或用于本文所描述的技术的其他由通信装置执行的过程。
可选的，通信装置还可以包括存储模块111，用于存储通信装置的程序代码和数据。
其中，处理模块112可以是处理器或控制器，例如可以是中央处理器单元，通用处理器，数字信号处理器，专用集成电路，现场可编程门阵列或者其他可编程逻辑器件、晶体管逻辑器件、硬件部件或者其任意组合。其可以实现或执行结合本申请公开内容所描述的各种示例性的逻辑方框，模块和电路。处理器也可以是实现计算功能的组合，例如包含一个或多个微处理器组合，数字信号处理器和微处理器的组合等等。通信模块113可以是收发器、收发电路或通信接口等。存储模块111可以是存储器。
当处理模块112为处理器41或处理器45，通信模块113为通信接口或收发器43时，存储模块111为存储器42时，本申请所涉及的通信装置可以为图10所示的通信设备。
示例性的，当如图10所示的通信设备为源接入网设备时，例如，处理器41和/或处理器45支持源接入网设备执行上述实施例中的S103中确定源接入网设备接收到第一数据包的步骤。收发器43用于支持源接入网设备执行上述实施例中的S101、S103、S108。可选的，收发器43还用于支持源接入网设备执行上述实施例中的S109。
如图20所示，图20示出了本申请实施例提供的另一种通信装置的结构示意图，该通信装置可以是本申请实施例中的目标接入网设备，也可以为应用于目标接入网设备中的芯片。该通信装置可以用于执行上述各方法实施例中目标接入网设备，或T-RAN设备的动作。
该通信装置包括：发送单元201和接收单元202。其中，发送单元201用于支持该通信装置执行上述实施例中的S105。该接收单元202用于支持该通信装置执行上述实施例中的S102。
可选的，发送单元201还用于支持该通信装置执行上述实施例中的S105、S106、S107、S111。可选的，接收单元202还用于支持该通信装置执行上述实施例中的S110。
在采用集成的单元的情况下，图21示出了上述实施例中所涉及的通信装置的一种可能的结构示意图，该通信装置可以为目标接入网设备或者为应用于目标接入网设备中的芯片。通信装置包括：处理模块212和通信模块213。处理模块212用于对通信装置的动作进行控制管理，例如，处理模块212用于支持通信装置执行上述实施例中在通信装置侧进行消息或数据处理的操作。例如，确定终端从源接入网设备成功切换至目标接入网设备的过程。通信模块213用于支持通信装置执行上述实施例中在通信装置侧进行消息或数据接收和发送的操作，例如，上述实施例中的S102、S105。
可选的，通信模块213还用于支持通信装置执行上述实施例中的步骤：S106、S107、S110、S111。和/或用于本文所描述的技术的其他由通信装置执行的过程。
可选的，通信装置还可以包括存储模块211，用于存储通信装置的程序代码和数据。
其中，处理模块212可以是处理器或控制器，例如可以是中央处理器单元，通用处理器，数字信号处理器，专用集成电路，现场可编程门阵列或者其他可编程逻辑器件、晶体管逻辑器件、硬件部件或者其任意组合。其可以实现或执行结合本申请公开内容所描述的各种示例性的逻辑方框，模块和电路。处理器也可以是实现计算功能的组合，例如包含一个或多个微处理器组合，数字信号处理器和微处理器的组合等等。通信模块213可以是收发器、收发电路或通信接口等。存储模块211可以是存储器。
当处理模块212为处理器41或处理器45时，通信模块213为通信接口或收发器43时，存储模块211为存储器42时，本申请所涉及的通信装置可以为图10所示的设备。
示例性的，当如图10所示的通信设备为目标接入网设备时，处理器41或处理器45用于支持目标接入网设备执行上述实施例中在目标接入网设备侧进行消息或数据处理的操作。收发器43用于支持通信装置执行上述实施例中在通信装置侧进行消息或数据接收和发送的操作，例如，上述实施例中的S102、S105。可选的，收发器43还用于支持通信装置执行上述实施例中的S106、S107、S110、S111。
应理解以通信装置中单元的划分仅仅是一种逻辑功能的划分，实际实现时可以全部或部分集成到一个物理实体上，也可以物理上分开。且装置中的单元可以全部以软件通过处理元件调用的形式实现；也可以全部以硬件的形式实现；还可以部分单元以软件通过处理元件调用的形式实现，部分单元以硬件的形式实现。例如，各个单元可以为单独设立的处理元件，也可以集成在装置的某一个芯片中实现，此外，也可以以程序的形式存储于存储器中，由装置的某一个处理元件调用并执行该单元的功能。此外这些单元全部或部分可以集成在一起，也可以独立实现。这里所述的处理元件可以是一种集成电路，具有信号的处理能力。在实现过程中，上述方法的各步骤或以上各个单元可以通过处理器元件中的硬件的集成逻辑电路实现或者以软件通过处理元件调用的形式实现。
在一个例子中，以上任一装置中的单元可以是被配置成实施以上方法的一个或多个集成电路，例如：一个或多个特定集成电路(Application Specific Integrated Circuit，ASIC)，或，一个或多个微处理器(digital singnal processor，DSP)，或，一个或者多个现场可编程门阵列(Field Programmable Gate Array，FPGA)等。再如，当装置中的单元可以通过处理元件调度程序的形式实现时，该处理元件可以是通用处理器，例如中央处理器(Central Processing Unit，CPU)或其它可以调用程序的处理器。再如，这些单元可以集成在一起，以片上系统(system-on-a-chip，SOC)的形式实现。
以上接收单元(或用于接收的单元)是一种该装置的通信接口或通信接口，用于从其它装置接收信号。例如，当该装置以芯片的方式实现时，该接收单元是该芯片用于从其它芯片或装置接收信号的通信接口或通信接口。以上发送单元(或用于发送的单元)是一种该装置的通信接口，用于向其它装置发送信号。例如，当该装置以芯片的方式实现时，该发送单元是该芯片用于向其它芯片或装置发送信号的通信接口或通信接口。
图22是本申请实施例提供的芯片150的结构示意图。芯片150包括至少一个处理器1510和通信接口1530。
可选的，该芯片150还包括存储器1540，存储器1540可以包括只读存储器和随机存取存储器，并向处理器1510提供操作指令和数据。存储器1540的一部分还可以包括非易失性随机存取存储器(non-volatile random access memory，NVRAM)。
在一些实施方式中，存储器1540存储了如下的元素，可执行模块或者数据结构，或者他们的子集，或者他们的扩展集：
在本申请实施例中，通过调用存储器1540存储的操作指令(该操作指令可存储在操作系统中)，执行相应的操作。
一种可能的实现方式为：源接入网设备、目标接入网设备所用的芯片的结构类似，不同的装置可以使用不同的芯片以实现各自的功能。
处理器1510控制源接入网设备、目标接入网设备的操作，处理器1510还可以称为CPU(central processing unit，中央处理单元)。存储器1540可以包括只读存储器和随机存取存储器，并向处理器1510提供指令和数据。存储器1540的一部分还可以包括非易失性随机存取存储器(NVRAM)。具体的应用中存储器1540、通信接口1530以及存储器1540通过总线系统1520耦合在一起，其中总线系统1520除包括数据总线之外，还可以包括电源总线、控制总线和状态信号总线等。但是为了清楚说明起见，在图22中将各种总线都标为总线系统1520。
上述本申请实施例揭示的方法可以应用于处理器1510中，或者由处理器1510实现。处理器1510可能是一种集成电路芯片，具有信号的处理能力。在实现过程中，上述方法的各步骤可以通过处理器1510中的硬件的集成逻辑电路或者软件形式的指令完成。上述的处理器1510可以是通用处理器、数字信号处理器(digital signal processing，DSP)、专用集成电路(application specific integrated circuit，ASIC)、现成可编程门阵列(field-programmable gate array，FPGA)或者其他可编程逻辑器件、分立门或者晶体管逻辑器件、分立硬件组件。可以实现或者执行本申请实施例中的公开的各方法、步骤及逻辑框图。通用处理器可以是微处理器或者该处理器也可以是任何常规的处理器等。结合本申请实施例所公开的方法的步骤可以直接体现为硬件译码处理器执行完成，或者用译码处理器中的硬件及软件模块组合执行完成。软件模块可以位于随机存储器，闪存、只读存储器，可编程只读存储器或者电可擦写可编程存储器、寄存器等本领域成熟的存储介质中。该存储介质位于存储器1540，处理器1510读取存储器1540中的信息，结合其硬件完成上述方法的步骤。
可选地，通信接口1530用于执行图11、图13-图17所示的实施例中的源接入网设备、目标接入网设备的接收和发送的步骤。
处理器1510用于执行图11、图13-图17所示的实施例中的源接入网设备、目标接入网设备的处理的步骤。
在上述实施例中，存储器存储的供处理器执行的指令可以以计算机程序产品的形式实现。计算机程序产品可以是事先写入在存储器中，也可以是以软件形式下载并安装在存储器中。
计算机程序产品包括一个或多个计算机指令。在计算机上加载和执行计算机程序指令时，全部或部分地产生按照本申请实施例的流程或功能。计算机可以是通用计算机、专用计算机、计算机网络、或者其他可编程装置。计算机指令可以存储在计算机 可读存储介质中，或者从一个计算机可读存储介质向另一计算机可读存储介质传输，例如，计算机指令可以从一个网站站点、计算机、服务器或数据中心通过有线(例如同轴电缆、光纤、数字用户线(digital subscriber line，DSL))或无线(例如红外、无线、微波等)方式向另一个网站站点、计算机、服务器或数据中心进行传输。计算机可读存储介质可以是计算机能够存储的任何可用介质或者是包含一个或多个可用介质集成的服务器、数据中心等数据存储设备。可用介质可以是磁性介质，(例如，软盘、硬盘、磁带)、光介质(例如，DVD)、或者半导体介质(例如固态硬盘solid state disk，SSD)等。
一方面，提供一种计算机存储介质，计算机可读存储介质中存储有指令，当指令被运行时，使得源接入网设备或者应用于源接入网设备中的芯片执行实施例中的S101、S103、S108、S109。
又一方面，提供一种计算机存储介质，计算机可读存储介质中存储有指令，当指令被运行时，使得目标接入网设备或者应用于目标接入网设备中的芯片执行实施例中的S102、S105、S106、S107、S110、S111。
前述的可读存储介质可以包括：U盘、移动硬盘、只读存储器、随机存取存储器、磁碟或者光盘等各种可以存储程序代码的介质。
一方面，提供一种包含指令的计算机程序产品，计算机程序产品中存储有指令，当指令被运行时，使得源接入网设备或者应用于源接入网设备中的芯片执行实施例中的源接入网设备执行上述实施例中的S101、S103、S108、S109。
又一方面，提供一种包含指令的计算机程序产品，计算机程序产品中存储有指令，当指令被运行时，使得目标接入网设备或者应用于目标接入网设备中的芯片执行实施例中的S102、S105、S106、S107、S110、S111。
一方面，提供一种芯片，该芯片应用于源接入网设备中，芯片包括至少一个处理器和通信接口，通信接口和至少一个处理器耦合，处理器用于运行指令，以执行实施例中的S101、S103、S108、S109。
又一方面，提供一种芯片，该芯片应用于目标接入网设备中，芯片包括至少一个处理器和通信接口，通信接口和至少一个处理器耦合，处理器用于运行指令，以执行实施例中实施例中的S102、S105、S106、S107、S110、S111。
一方面，本申请提供一种通信系统，该通信系统包括：如图18所描述的通信装置、图20所描述的通信装置以及终端。
又一方面，本申请提供一种通信系统，该通信系统包括：如图19所描述的通信装置、图21所描述的通信装置以及终端。
尽管结合具体特征及其实施例对本申请进行了描述，显而易见的，在不脱离本申请的精神和范围的情况下，可对其进行各种修改和组合。相应地，本说明书和附图仅仅是所附权利要求所界定的本申请的示例性说明，且视为已覆盖本申请范围内的任意和所有修改、变化、组合或等同物。显然，本领域的技术人员可以对本申请进行各种改动和变型而不脱离本申请的精神和范围。这样，倘若本申请的这些修改和变型属于本申请权利要求及其等同技术的范围之内，则本申请也意图包含这些改动和变型在内。

Claims (24)

  1. 一种通信方法，其特征在于，包括：
    源接入网设备向目标接入网设备发送终端的第一数据包；
    当所述源接入网设备确定所述目标接入网设备接收到所述第一数据包时，所述源接入网设备向所述终端发送第一消息，所述第一消息用于指示所述终端切换至所述目标接入网设备。
  2. 根据权利要求1所述的方法，其特征在于，所述方法还包括：
    所述源接入网设备接收来自所述目标接入网设备的第一信息，所述第一信息用于指示允许所述终端切换至所述目标接入网设备；
    所述源接入网设备向所述目标接入网设备发送所述第一数据包。
  3. 根据权利要求2所述的方法，其特征在于，在所述源接入网设备向所述目标接入网设备发送所述第一数据包之前，所述方法还包括：
    所述源接入网设备根据所述第一信息，确定所述目标接入网设备允许所述终端切换至所述目标接入网设备。
  4. 根据权利要求1-3任一项所述的方法，其特征在于，所述第一数据包包括复制数据包，所述方法还包括：
    所述源接入网设备获得所述复制数据包；或者，
    当满足为所述终端切换接入网设备的条件时，所述源接入网设备获得所述复制数据包。
  5. 根据权利要求4所述的方法，其特征在于，所述源接入网设备获得所述复制数据包，包括：
    所述源接入网设备对所述终端的数据包中满足预设条件的数据包进行复制，得到所述复制数据包；其中，所述满足预设条件的数据包包括以下情况中的至少一种：使用预设服务质量QoS流的数据包，预设分组数据单元PDU会话上的数据包，丢包率小于或等于预设门限值的数据包，或者预设无线承载上的数据包；或者，
    所述源接入网设备对所述终端的数据包进行复制，得到所述复制数据包。
  6. 根据权利要求1-5任一项所述的方法，其特征在于，所述方法还包括：
    所述源接入网设备向所述目标接入网设备发送序列号SN状态信息，所述SN状态信息用于所述目标接入网设备向所述终端发送数据包。
  7. 根据权利要求1-6任一项所述的方法，其特征在于，所述源接入网设备确定所述目标接入网设备接收到所述第一数据包，包括：
    所述源接入网设备接收所述目标接入网设备发送的第二消息，所述第二消息用于指示所述目标接入网设备接收到所述第一数据包；或者，
    所述源接入网设备根据时延信息确定所述目标接入网设备接收到所述第一数据包。
  8. 根据权利要求7所述的方法，其特征在于，所述方法还包括：
    所述源接入网设备根据所述第一数据包的服务质量QoS信息，确定所述时延信息；或，
    所述源接入网设备从会话管理功能网元获取所述时延信息。
  9. 一种通信方法，其特征在于，包括：
    目标接入网设备向源接入网设备发送第一信息，所述第一信息用于指示允许终端切换至所述目标接入网设备；
    所述目标接入网设备接收来自所述源接入网设备的所述终端的第一数据包；
    当所述终端从所述源接入网设备成功切换至所述目标接入网设备时，所述目标接入网设备向所述终端发送所述第一数据包。
  10. 根据权利要求9所述的方法，其特征在于，所述方法还包括：
    所述目标接入网设备向所述源接入网设备发送第二消息，所述第二消息用于指示所述目标接入网设备接收到所述第一数据包。
  11. 根据权利要求9或10所述的方法，其特征在于，所述方法还包括：
    所述目标接入网设备接收来自所述源接入网设备的序列号SN状态信息；
    所述目标接入网设备根据所述SN状态信息和处理来自所述源接入网设备未携带有SN的数据包，得到第二数据包；所述未携带有SN的数据包为所述第一数据包中的数据包或者所述源接入网设备中的所述终端的数据包；
    所述目标接入网设备向所述终端发送所述第二数据包。
  12. 一种通信装置，其特征在于，所述通信装置为源接入网设备或者为应用于所述源接入网设备中的芯片，所述通信装置包括：发送单元和处理单元，其中，
    所述发送单元，用于向目标接入网设备发送终端的第一数据包；
    所述发送单元，还用于当所述处理单元确定所述目标接入网设备接收到所述第一数据包时，向所述终端发送第一消息，所述第一消息用于指示所述终端切换至所述目标接入网设备。
  13. 根据权利要求12所述的通信装置，其特征在于，所述通信装置还包括：
    接收单元，用于接收来自所述目标接入网设备的第一信息，所述第一信息用于指示允许所述终端切换至所述目标接入网设备；
    所述发送单元，还用于向所述目标接入网设备发送所述第一数据包。
  14. 根据权利要求13所述的通信装置，其特征在于，所述处理单元，还用于根据所述第一信息，确定所述目标接入网设备允许所述终端切换至所述目标接入网设备。
  15. 根据权利要求12-14任一项所述的通信装置，其特征在于，所述第一数据包包括复制数据包，所述处理单元，还用于获得所述复制数据包；或者，
    所述处理单元，还用于当满足为所述终端切换接入网设备的条件时，获得所述复制数据包。
  16. 根据权利要求15所述的通信装置，其特征在于，所述处理单元，还具体用于所述终端的数据包中满足预设条件的数据包进行复制，得到所述复制数据包；其中，所述满足预设条件的数据包包括以下情况中的至少一种：使用预设服务质量QoS流的数据包，预设分组数据单元PDU会话上的数据包，丢包率小于或等于预设门限值的数据包，或者预设无线承载上的数据包；或者，
    所述处理单元，还具体用于对所述终端的数据包进行复制，得到所述复制数据包。
  17. 根据权利要求12-16任一项所述的通信装置，其特征在于，所述发送单元，还用于向所述目标接入网设备发送序列号SN状态信息，所述SN状态信息用于所述目标接入网设备向所述终端发送数据包。
  18. 根据权利要求12-17任一项所述的通信装置，其特征在于，接收单元，还用于接收所述目标接入网设备发送的第二消息，所述第二消息用于指示所述目标接入网设备接收到所述第一数据包；或者，
    所述处理单元，具体用于根据时延信息确定所述目标接入网设备接收到所述第一数据包。
  19. 根据权利要求18所述的通信装置，其特征在于，所述处理单元，具体用于根据所述第一数据包的服务质量QoS信息，确定所述时延信息；或，所述处理单元，具体用于从会话管理功能网元获取所述时延信息。
  20. 一种通信装置，其特征在于，所述通信装置为目标接入网设备或者为应用于所述目标接入网设备中的芯片，所述通信装置，包括：
    发送单元，用于向源接入网设备发送第一信息，所述第一信息用于指示允许终端切换至所述目标接入网设备；
    接收单元，用于接收来自所述源接入网设备的所述终端的第一数据包；
    所述发送单元，用于当所述终端从所述源接入网设备成功切换至所述目标接入网设备时，向所述终端发送所述第一数据包。
  21. 根据权利要求20所述的通信装置，其特征在于，所述发送单元，还用于向所述源接入网设备发送第二消息，所述第二消息用于指示所述目标接入网设备接收到所述第一数据包。
  22. 根据权利要求20或21所述的通信装置，其特征在于，所述接收单元，还用于接收来自所述源接入网设备的序列号SN状态信息；
    所述发送单元，还用于根据所述SN状态信息和处理来自所述源接入网设备未携带有SN的数据包，得到第二数据包；所述未携带有SN的数据包为所述第一数据包中的数据包或者所述源接入网设备中的所述终端的数据包；
    所述发送单元，还用于向所述终端发送所述第二数据包。
  23. 一种芯片，其特征在于，所述芯片包括处理器和通信接口，所述通信接口和所述处理器耦合，所述处理器用于运行计算机程序或指令，以实现如权利要求1至8任一项所述的通信方法，或者以实现权利要求9至11任一项所述的通信方法，所述通信接口用于与所述芯片之外的其它模块进行通信。
  24. 一种计算机可读存储介质，其特征在于，所述计算机可读存储介质中存储有计算机程序或指令，当所述计算机程序或指令被运行时，实现如权利要求1至8任一项所述的通信方法，或者以实现权利要求9至11任一项所述的通信方法。
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