WO2024067206A1 - 一种通信方法、通信装置及系统 - Google Patents

一种通信方法、通信装置及系统 Download PDF

Info

Publication number
WO2024067206A1
WO2024067206A1 PCT/CN2023/119407 CN2023119407W WO2024067206A1 WO 2024067206 A1 WO2024067206 A1 WO 2024067206A1 CN 2023119407 W CN2023119407 W CN 2023119407W WO 2024067206 A1 WO2024067206 A1 WO 2024067206A1
Authority
WO
WIPO (PCT)
Prior art keywords
network device
access network
terminal device
context
terminal
Prior art date
Application number
PCT/CN2023/119407
Other languages
English (en)
French (fr)
Inventor
仲亚萍
胡星星
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
Publication of WO2024067206A1 publication Critical patent/WO2024067206A1/zh

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W4/00—Services specially adapted for wireless communication networks; Facilities therefor
    • H04W4/24—Accounting or billing
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W48/00—Access restriction; Network selection; Access point selection
    • H04W48/08—Access restriction or access information delivery, e.g. discovery data delivery
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W48/00—Access restriction; Network selection; Access point selection
    • H04W48/08—Access restriction or access information delivery, e.g. discovery data delivery
    • H04W48/12—Access restriction or access information delivery, e.g. discovery data delivery using downlink control channel
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W48/00—Access restriction; Network selection; Access point selection
    • H04W48/18—Selecting a network or a communication service
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W76/00—Connection management
    • H04W76/10—Connection setup
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W84/00—Network topologies
    • H04W84/02—Hierarchically pre-organised networks, e.g. paging networks, cellular networks, WLAN [Wireless Local Area Network] or WLL [Wireless Local Loop]
    • H04W84/04—Large scale networks; Deep hierarchical networks
    • H04W84/06—Airborne or Satellite Networks

Definitions

  • the embodiments of the present application relate to the field of communications, and in particular, to a communication method, a communication device, and a system.
  • satellites as access network devices can not only exchange signaling with ground terminal devices through service links, but also connect to the ground NTN gateway through feeder links, and then exchange signaling with core network devices through the ground NTN gateway.
  • ground-based NTN gateways may be restricted by terrain (for example, NTN gateways cannot be deployed on the sea surface), which results in the inability of deployed NTN gateways to cover all satellites. Therefore, some satellites that provide services to terminal devices may not be able to establish a connection with the core network device through the NTN gateway, resulting in the inability of the terminal device to exchange non-access stratum (NAS) signaling with the core network device through the access network device, which may trigger the terminal device to try to re-access the next access network device when the NAS timer times out to seek network services.
  • NAS non-access stratum
  • the terminal device re-accesses the next access network device, it generally needs to reconfigure the access-related information. Therefore, it may take a long time for the terminal device to access the next access network device, resulting in low efficiency of the terminal device accessing the network device, affecting the communication experience.
  • the present application provides a communication method, a communication device and a system for improving the efficiency of establishing a connection between a terminal device and an access network device, and saving the signaling overhead of establishing a connection between the terminal device and a second access network device.
  • the present application provides a communication method, which can be executed by a terminal device or by a component of the terminal device (for example, a processor, a chip, or a chip system).
  • the terminal device receives first indication information from a first access network device, and the first indication information is used to indicate that the first access network device cannot interact with a core network device; after the terminal device accesses the first access network device, the terminal device stores the context of the terminal device according to the first indication information, and the context of the terminal device is information used by the terminal device to access the second access network device after the first access network device stops providing services for the terminal device.
  • the first indication information only indicates that the first access network device currently has no connection with the core network device, but the first access network device has the ability to establish a connection with the core network device, and the first access network device may establish a connection with the core network device at some point in the future.
  • the first indication information may be identification information describing the state of the first access network device, for example, an identification of no CN connection.
  • the first indication information may also be identification information describing a data transmission mode, for example, an identification of a store and forward mode.
  • other identification information or indication information may be used to implement the aforementioned first indication information, and the present application does not limit the specific implementation form of the first indication information.
  • the second access network device is an access network device having the context of the terminal device.
  • the terminal device can determine that the first access network device has not established a connection with the core network device based on the first indication information from the first access network device, and the terminal device stores the context of the terminal device in the process of establishing a connection with the first access network device (or after the connection is established) based on the first indication information.
  • the context of the terminal device records the access-related information used by the terminal device when accessing the first access network device.
  • the terminal device can use the access-related information already in the context of the terminal device to access the second access network device without the need for the second access network device to re-initialize the RRC.
  • the method further includes: after the first access network device stops providing services for the terminal device, the terminal device establishes a connection with the second access network device based on the context of the terminal device.
  • the second access network device and the first access network device are the same access network device. For example, after the first access network device stops providing services to the terminal device for a period of time, the first access network device moves again to the geographical area where the terminal device is located, and then the terminal device establishes a connection with the first access network device again. At this time, the terminal device connects to the second access network device based on the context of the terminal device, including: the terminal device accesses the first cell of the first access network device based on the context of the terminal device, and the first cell is a cell stored in the context of the terminal device.
  • the terminal device may access the first cell of the first access network device based on the context of the terminal device based on any one of the following implementations.
  • the context of the terminal device includes the cell identification information of the first cell.
  • the terminal device if the terminal device receives the cell identification information of the first cell from the first access network device, the terminal device accesses the first cell based on the cell identification information of the first cell.
  • the cell identification information of the first cell stored in the context of the terminal device indicates that the first cell is a cell that the terminal device has accessed before (for example, a cell that the terminal device accessed when the first access network device provided services to the terminal device).
  • the context of the terminal device may record relevant configuration information of the terminal device accessing the first cell. Therefore, the terminal device will have a higher probability of accessing the first cell based on the context of the terminal device, which is conducive to improving the efficiency of the terminal device accessing the first access network device.
  • the terminal device receives second indication information from the first access network device, where the second indication information is used to instruct the terminal device to initiate access; and the terminal device accesses the first cell of the first access network device based on the second indication information.
  • the terminal device can access the first access network device under the instruction of the second indication information sent by the first access network device, which is conducive to improving the efficiency of the terminal device accessing the first access network device.
  • the second access network device and the first access network device are different access network devices.
  • the terminal device may access the second access network device based on the context of the terminal device based on any of the following implementation manners.
  • the context of the terminal device includes cell identification information of the first cell. If the terminal device receives the cell identification information of the first cell from the second access network device, the terminal device accesses the second cell of the second access network device based on the cell identification information of the first cell.
  • the second access network device broadcasts the cell identification information of the first cell in the system message to instruct the terminal device that has accessed the first cell to access the second access network device, which is beneficial to improving the efficiency of the terminal device accessing the second access network device.
  • the terminal device receives third indication information from the second access network device, where the third indication information is used to instruct the terminal device to initiate access; and the terminal device accesses the second cell of the second access network device based on the third indication information.
  • the terminal device can access the second access network device under the instruction of the third indication information sent by the second access network device, which is conducive to improving the efficiency of the terminal device accessing the second access network device.
  • the method before the terminal device stores the context of the terminal device according to the first indication information, the method further includes: the terminal device receives first identification information from the first access network device, and the first identification information is used to uniquely identify the terminal device for the first access network device.
  • the first identification information is used to uniquely identify the terminal device at different positions of the first access network device on the running track. That is, no matter where the first access network device moves to on the track, and for which terminal devices the first access network device configures identification, the first identification information can uniquely identify the terminal device.
  • the length of the first identification information is greater than the length of the cell wireless network temporary identification.
  • the terminal device can receive the first identification information configured for the terminal device by the first access network device, which is beneficial for the first access network device to quickly find information related to the terminal device (for example, the context of the terminal device and the NAS message of the terminal device, etc.) during subsequent signaling interaction.
  • the method before the first access network device stops providing services for the terminal device, the method further includes: the terminal device sends an uplink NAS message of the terminal device to the first access network device; after the terminal device establishes a connection with the second access network device based on the context of the terminal device, the method further includes: the terminal device sends the first identification signal to the second access network device The first identification information is used by the second access network device to determine the context of the terminal device; the terminal device receives a downlink NAS message of the terminal device from the second access network device.
  • the method before the first access network device stops providing services for the terminal device, the method also includes: the terminal device starts a first NAS timer when sending an uplink NAS message, and the first NAS timer is a NAS timer used when the access network device cannot interact with the core network device; or, the terminal device starts a second NAS timer after a first period of time after sending the uplink NAS message, and the second NAS timer is a NAS timer used when the access network device can interact with the core network device.
  • the duration of the first NAS timer is greater than the duration of the second NAS timer.
  • the duration of the second NAS timer may be predefined by the protocol or may be preconfigured, which is not limited here.
  • the duration for the terminal device to wait for the downlink NAS message fed back by the core network device can be extended, which is beneficial to delaying the terminal device from triggering a cell reselection or other processes due to the NAS timer (for example, the first NAS timer or the second NAS timer) timing out, so that the terminal device is in a state of waiting for the downlink NAS message.
  • the NAS timer for example, the first NAS timer or the second NAS timer
  • the method further includes: the terminal device receiving first time information from the first access network device, the first time information being used to determine the duration of the first NAS timer or the first duration. Then, the terminal device determines the duration of the first NAS timer or the first duration based on the first time information.
  • the terminal device can determine the duration of the first NAS timer based on the first time information from the first access network device, which is beneficial for the terminal device to postpone the process of triggering cell reselection due to the expiration of the NAS timer (for example, the first NAS timer or the second NAS timer) when the access network device has not established a connection with the core network device, so that the terminal device is in a state of waiting for a downlink NAS message.
  • the NAS timer for example, the first NAS timer or the second NAS timer
  • the present application provides a communication method, which can be executed by an access network device or by a component of the access network device (e.g., a processor, a chip, or a chip system).
  • the first access network device broadcasts a first indication information, and the first indication information is used to indicate that the first access network device cannot interact with the core network device; after the first access network device establishes a connection with the terminal device, the first access network device stores the context of the terminal device, and the context of the terminal device is the information that the second access network device accepts the use of the terminal device after the first access network device stops providing services for the terminal device.
  • the first access network device can provide the first indication information to the terminal device, so that the terminal device can determine that the first access network device has not established a connection with the core network device based on the first indication information from the first access network device, thereby prompting the terminal device to store the context of the terminal device based on the first indication information during the process of establishing a connection with the first access network device (or after the connection is established).
  • the first access network device will also store the context of the terminal device after establishing a connection with the terminal device, which is conducive to the first access network device using the stored context of the terminal device to establish a connection with the terminal device again, or the first access network device forwards the context of the terminal device to the second access network device, and the second access network device uses the stored context of the terminal device to establish a connection with the terminal device again.
  • the first access network device broadcasts the first indication information, including: the first access network device broadcasts the first indication information in a first area, where the first area is an area where the access network device cannot establish a connection with the core network device.
  • the method before the first access network device stops providing services for the terminal device, the method further includes: the first access network device receives an uplink NAS message from the terminal device in the first area; after the first access network device stores the context of the terminal device, the method further includes: when the first access network device moves to a second area, the first access network device sends the uplink NAS message to the core network device, and the second area is an area where the access network device can establish a connection with the core network device.
  • the second access network device is the first access network device.
  • the method further includes: when the first access network device moves to the first area again, the first access network device establishes a connection with the terminal device based on the context of the terminal device.
  • the first access network device establishes a connection with the terminal device based on the context of the terminal device, including: the first access network device provides services for the terminal device through a first cell of the first access network device based on the context of the terminal device, and the first cell is the cell to which the terminal device accesses when the first access network device stores the context of the terminal device.
  • the method before the first access network device establishes a connection with the terminal device based on the context of the terminal device, the method also includes: the first access network device broadcasts cell identification information of the first cell in the first area, and the cell identification information of the first cell is used for the terminal device to access the first cell.
  • the method before the first access network device establishes a connection with the terminal device based on the context of the terminal device, the method also includes: the first access network device sends second indication information to the terminal device in the first cell, and the second indication information is used to instruct the terminal device to initiate access based on the context of the terminal device.
  • the method further includes: the first access network device receives a downlink NAS message of the terminal device from the core network device in the second area; after the first access network device establishes a connection with the terminal device based on the context of the terminal device, the method further includes: the first access network device sends the downlink NAS message to the terminal device.
  • the method before the first access network device receives an uplink NAS message from the terminal device in the first area, the method further includes: the first access network device sends first identification information to the terminal device, and the first identification information is used to uniquely identify the terminal device for the first access network device; before the first access network device sends the downlink NAS message to the terminal device, the method further includes: the first access network device receives the first identification information from the terminal device; the first access network device determines the context of the terminal device based on the first identification information of the terminal device; the first access network device determines the downlink NAS message based on the context of the terminal device.
  • the context of the terminal device includes the geographical area information of the terminal device; before the first access network device sends the downlink NAS message to the terminal device, the method also includes: the first access network device determines the context of the terminal device based on the cell wireless network temporary identifier of the terminal device and the geographical area information of the terminal device; the first access network device determines the downlink NAS message based on the context of the terminal device.
  • the context of the terminal device includes time information when the terminal device accesses the first access network device; before the first access network device sends the downlink NAS message to the terminal device, the method also includes: the first access network device determines the context of the terminal device based on the cell wireless network temporary identifier of the terminal device and the time information when the terminal device accesses the first access network device; the first access network device determines the downlink NAS message based on the context of the terminal device.
  • the second access network device and the first access network device are different access network devices; after the first access network device stores the context of the terminal device, the method further includes: when the first access network device moves to a second area, the first access network device sends the context of the terminal device to the core network device, the second area being an area where the access network device can establish a connection with the core network device, and the context of the terminal device is used for the second access network device determined by the core network device to establish a connection with the terminal device.
  • the method before the first access network device receives an uplink NAS message from a terminal device in the first area, the method further includes: the first access network device broadcasts first time information in the first area, and the first time information is used to determine a first NAS timer.
  • the method also includes: when the first access network device moves to the second area, the first access network device sends a fourth indication message to the core network device, and the fourth indication message is used to indicate that the terminal device accesses the first access network device when the first access network device cannot establish a connection with the core network device.
  • the method further includes: when the first access network device moves to the second area, the first access network device sends first time information to the core network device, where the first time information is used to determine a first NAS timer of the core network device.
  • the present application provides a communication method, which can be executed by a core network device or by a component of the core network device (e.g., a processor, a chip, or a chip system).
  • the core network device receives an uplink NAS message and fourth indication information of a terminal device from a first access network device, the fourth indication information being used to indicate that the terminal device accesses the first access network device when the first access network device cannot establish a connection with the core network device, and the fourth indication information is also used by the core network device to start a first NAS timer when sending a downlink NAS message.
  • the method further includes: the core network device receiving first time information from the first access network device, where the first time information is used to determine the first NAS timer.
  • the method further includes: the core network device sends a downlink NAS message of the terminal device to the first access network device, and the core network device starts the first NAS timer; before the first NAS timer times out, the core network device receives an uplink NAS message corresponding to the downlink NAS message from the first access network device.
  • the method further includes: the core network device sends a downlink NAS message of the terminal device to a second access network device, and the core network device starts the first NAS timer, the second access network device is an access network device that is about to move to the geographical area where the terminal device is located; before the first NAS timer times out, the core network device receives an uplink NAS message corresponding to the downlink NAS message.
  • the method further includes: the core network device receives the context of the terminal device from the first access network device; and the core network device sends the context of the terminal device to the second access network device.
  • the present application provides a communication method, which can be executed by an access network device or by a component of the access network device (for example, a processor, a chip, or a chip system).
  • the second access network device receives the context of the terminal device and the downlink NAS message of the terminal device from the core network device; the second access network device determines the geographical area where the terminal device is located based on the context of the terminal device; when the second access network device moves to the geographical area where the terminal device is located, the second access network device sends a second indication information to the terminal device, and the second indication information is used to instruct the terminal device to initiate random access; after the terminal device accesses, the second access network device sends the downlink NAS message of the terminal device to the terminal device.
  • the method before sending a downlink NAS message of the terminal device to the terminal device, the method also includes: the second access network device receives first identification information from the terminal device, and the first identification information is used to uniquely identify the terminal device for the first access network device; the second access network device determines the context of the terminal device based on the first identification information; and the second access network device determines the downlink NAS message based on the context of the terminal device.
  • the context of the terminal device includes the geographical area information of the terminal device; before the second access network device sends the downlink NAS message to the terminal device, the method also includes: the second access network device determines the context of the terminal device based on the cell wireless network temporary identifier of the terminal device and the geographical area information of the terminal device; the second access network device determines the downlink NAS message based on the context of the terminal device.
  • the context of the terminal device includes time information when the terminal device accesses the first access network device; before the second access network device sends the downlink NAS message to the terminal device, the method also includes: the second access network device determines the context of the terminal device based on the cell wireless network temporary identifier of the terminal device and the time information when the terminal device accesses the first access network device; the second access network device determines the downlink NAS message based on the context of the terminal device.
  • the present application provides a communication method, which can be executed by a core network device or by a component of the core network device (for example, a processor, a chip, or a chip system).
  • the core network device determines at least one access network device according to the geographical area information of the terminal device, the current coverage area of the access network device does not include the geographical area where the terminal device is located, and the mobile path of the coverage area of the access network device passes through the geographical area where the terminal device is located; the core network device sends a paging message to the at least one access network device, and the paging message includes the geographical area information of the terminal device.
  • the geographical area information of the terminal device is used to indicate the geographical area where the terminal device is located.
  • the geographical area information of the terminal device can be stored in the context of the terminal device in the core network device. For example, after the terminal device is registered with the core network device, the core network device establishes the context of the terminal device.
  • the core network device can determine at least one access network device for paging the terminal device based on the geographical area information of the terminal device, rather than directly determining the access network device for paging the terminal device based on the TA list, which is beneficial to improving the probability of the core network device successfully paging the terminal device.
  • the method further includes: when the core network device sends the paging message, the core network device starts a first paging timer, and the duration of the first paging timer is greater than the duration of a preconfigured paging timer.
  • the core network device If the core network device can receive a response message from the terminal device during the operation of the first paging timer, the core network device successfully pages the terminal device; if the core network device does not receive a response message from the terminal device during the operation of the first paging timer, the core network device fails to page the terminal device.
  • the present application provides a communication method, which can be executed by an access network device or by an access network device.
  • the third access network device is executed by a component (for example, a processor, a chip, or a chip system).
  • the third access network device receives a paging message, and the paging message includes the geographical area information of the terminal device; when the third access network device moves to the geographical area where the terminal device is located, the third access network device broadcasts the paging message in the geographical area where the terminal device is located.
  • the method also includes: the third access network device sends a fifth indication message to a fourth access network device, the fourth access network device is an access network device that provides services to the terminal device after the third access network device stops providing services to the terminal device, and the fifth indication information is used to instruct the fourth access network device to delete a paging message used to page the terminal device.
  • the fourth access network device continues to page the terminal device; when the third access network device successfully pages the terminal device, the third access network device sends fifth indication information to the fourth access network device, and the fifth indication information is used to instruct the fourth access network device to delete the paging message used to page the terminal device. Since the number of times the terminal device receives the paging message can be reduced, it is beneficial to save the power of the terminal device.
  • the present application provides a communication method, which can be executed by a core network device or by a component of the core network device (for example, a processor, a chip, or a chip system).
  • the core network device sends multiple data packets of a terminal device to a fifth access network device, each of which corresponds to a first sequence number; the core network device sends the context of the terminal device and multiple data packets of the terminal device to a sixth access network device, the sixth access network device is an access network device that provides services to the terminal device after the fifth access network device stops providing services to the terminal device, and the context of the terminal device is used by the sixth access network device to establish a connection with the terminal device and send multiple data packets of the terminal device to the terminal device.
  • the core network device can copy multiple data packets of the terminal device and send the data packets of the terminal device to multiple access network devices, and send the context of the terminal device to multiple access network devices, when one of the access network devices cannot send all the data packets to the terminal device, the data packets can be sent to the terminal device through other access network devices. This is conducive to maintaining the continuity of the data received by the terminal device.
  • the present application provides a communication method, which can be executed by an access network device or by a component of the access network device (for example, a processor, a chip, or a chip system).
  • the fifth access network device receives multiple data packets of a terminal device from a core network device, each of which corresponds to a first sequence number; when the fifth access network device moves to the geographical area where the terminal device is located, the fifth access network device sends the data packet carrying the first sequence number to the terminal device based on the first sequence number; or, when the fifth access network device moves to the geographical area where the terminal device is located, the fifth access network device determines the second sequence number of each data packet based on the first sequence number of each data packet and the first mapping rule, and sends the data packet carrying the second sequence number to the terminal device based on the second sequence number.
  • the method further includes: before the fifth access network device stops providing services to the terminal device, sending sixth indication information to the terminal device, where the sixth indication information is used to indicate that there is a data packet to be sent.
  • the present application provides a communication method, which can be executed by an access network device or by a component of the access network device (e.g., a processor, a chip, or a chip system).
  • the sixth access network device receives multiple data packets of a terminal device and a context of the terminal device from a core network device, each of which corresponds to a first sequence number; the sixth access network device establishes a connection with the terminal device based on the context of the terminal device; the sixth access network device receives seventh indication information from the terminal device, the seventh indication information is used to indicate the data packets that the terminal device has successfully received continuously; the sixth access network device sends at least one of the multiple data packets to the terminal device based on the seventh indication information.
  • the seventh indication information includes a target sequence number, where the target sequence number is the sequence number of the last data packet that the terminal device has continuously confirmed to have received.
  • the target sequence number is a first sequence number
  • the sixth access network device sends at least one of the multiple data packets to the terminal device based on the target sequence number, including: the sixth access network device sends at least one data packet carrying the first sequence number to the terminal device, and the first sequence number of each data packet in the at least one data packet is greater than the target sequence number.
  • the target sequence number is a second sequence number
  • the sixth access network device sends at least one of the multiple data packets to the terminal device based on the target sequence number, including: the sixth access network device determines the second sequence number of each of the data packets based on the first sequence number of each of the data packets and a first mapping rule; the sixth access network device sends at least one data packet carrying the second sequence number to the terminal device, the second sequence number of each of the at least one data packet being greater than the target sequence number.
  • the present application provides a communication method, which can be executed by a terminal device or by a part of the terminal device.
  • the method comprises the steps of: performing the following steps ...
  • the seventh indication information includes a target sequence number, where the target sequence number is the sequence number of the last data packet that the terminal device has continuously confirmed to have received.
  • the method before the fifth access network device stops providing services for the terminal device, the method further includes: the terminal device receives sixth indication information from the fifth access network device, where the sixth indication information is used to indicate that there is a data packet to be sent.
  • an embodiment of the present application provides a communication device, which may be a terminal device in the aforementioned embodiment, or a chip in the terminal device.
  • the communication device may include a processing module and a transceiver module.
  • the processing module may be a processor, and the transceiver module may be a transceiver;
  • the terminal device may also include a storage module, and the storage module may be a memory; the storage module is used to store instructions, and the processing module executes the instructions stored in the storage module so that the terminal device executes the method in the first aspect or any one of the embodiments of the first aspect; or, executes the method in the tenth aspect or any one of the embodiments of the tenth aspect.
  • the processing module may be a processor, and the transceiver module may be an input/output interface, a pin or a circuit, etc.; the processing module executes the instructions stored in the storage module so that the terminal device executes the method in the first aspect or any one of the embodiments of the first aspect; or, executes the method in the tenth aspect or any one of the embodiments of the tenth aspect.
  • the storage module may be a storage module in the chip (for example, a register, a cache, etc.), or it may be a storage module in the terminal device located outside the chip (for example, a read-only memory, a random access memory, etc.).
  • the embodiment of the present application provides a communication device, which may be an access network device in the aforementioned implementation mode, or a chip in the access network device.
  • the access network device may be the first access network device, the second access network device, the third access network device, the fourth access network device, the fifth access network device, and the sixth access network device, etc. introduced in the aforementioned aspects.
  • the communication device may include a processing module and a transceiver module.
  • the processing module may be a processor, and the transceiver module may be a transceiver; the access network device may also include a storage module, which may be a memory; the storage module is used to store instructions, and the processing module executes the instructions stored in the storage module, so that the first access network device executes the method in the second aspect or any one of the implementation modes of the second aspect; or, so that the second access network device executes the method in the fourth aspect or any one of the implementation modes of the fourth aspect; or, so that the third access network device executes the method in the sixth aspect or any one of the implementation modes of the sixth aspect; or, so that the fifth access network device executes the method in the eighth aspect or any one of the implementation modes of the eighth aspect; or, so that the sixth access network device executes the method in the ninth aspect or any one of the implementation modes of the ninth aspect.
  • the processing module may be a processor, and the transceiver module may be an input/output interface, a pin or a circuit, etc.; the processing module executes the instructions stored in the storage module so that the first access network device executes the method in the second aspect or any one of the implementations of the second aspect; or, so that the second access network device executes the method in the fourth aspect or any one of the implementations of the fourth aspect; or, so that the third access network device executes the method in the sixth aspect or any one of the implementations of the sixth aspect; or, so that the fifth access network device executes the method in the eighth aspect or any one of the implementations of the eighth aspect; or, so that the sixth access network device executes the method in the ninth aspect or any one of the implementations of the ninth aspect.
  • the storage module may be a storage module in the chip (e.g., a register, a cache, etc.), or a storage module in the access network device located outside the chip (e.g., a read-only memory, a random access memory, etc.).
  • an embodiment of the present application provides a communication device, which may be a core network device in the aforementioned implementation manner, or a chip in the core network device.
  • the communication device may include a processing module and a transceiver module.
  • the processing module may be a processor, and the transceiver module may be a transceiver;
  • the core network device may also include a storage module, and the storage module may be a memory; the storage module is used to store instructions, and the processing module executes the instructions stored in the storage module so that the core network device executes the method in the third aspect or any one of the implementation manners of the third aspect; or, executes the method in the fifth aspect or any one of the implementation manners of the fifth aspect; or, executes the method in the seventh aspect or any one of the implementation manners of the seventh aspect.
  • the processing module may be a processor, and the transceiver module may be an input/output interface, a pin or a circuit, etc.; the processing module executes the instructions stored in the storage module so that the core network device executes the method in the third aspect or any one of the implementation manners of the third aspect; or, executes the method in the fifth aspect or any one of the implementation manners of the fifth aspect; or, executes the seventh aspect or any one of the implementation manners of the seventh aspect.
  • the storage module may be a storage module within the chip (e.g., a register, a cache, etc.), or a storage module within the core network device that is located outside the chip (e.g., a read-only memory, a random access memory, etc.).
  • the present application provides a communication device, which may be an integrated circuit chip.
  • the integrated circuit chip includes a processor.
  • the processor is coupled to a memory, and the memory is used to store a program or instruction.
  • the communication device executes the method described in any one of the embodiments of the aforementioned various aspects.
  • an embodiment of the present application provides a computer program product comprising instructions, which, when executed on a computer, enables the computer to execute a method as described in any one of the aforementioned aspects.
  • an embodiment of the present application provides a computer-readable storage medium, including instructions, which, when executed on a computer, enable the computer to execute a method as described in any one of the embodiments in the preceding aspects.
  • an embodiment of the present application provides a communication system, which includes a terminal device executing the aforementioned first aspect and any one of the embodiments of the first aspect, a first access network device executing the aforementioned second aspect and any one of the embodiments of the second aspect, a core network device executing the aforementioned third aspect and any one of the embodiments of the third aspect, and a second access network device executing the aforementioned fourth aspect and any one of the embodiments of the fourth aspect.
  • an embodiment of the present application provides a communication system, which includes a terminal device, a core network device that executes the aforementioned fifth aspect and any one of the implementations of the fifth aspect, and a third access network device that executes the aforementioned sixth aspect and any one of the implementations of the sixth aspect.
  • an embodiment of the present application provides a communication system, which includes a core network device executing the aforementioned seventh aspect and any one of the implementations of the seventh aspect, a fifth access network device executing the aforementioned eighth aspect and any one of the implementations of the eighth aspect, a sixth access network device executing the aforementioned ninth aspect and any one of the implementations of the ninth aspect, and a terminal device executing the aforementioned tenth aspect and any one of the implementations of the tenth aspect.
  • FIG1A is a diagram of a network architecture applicable to the communication method of the present application.
  • FIG1B is another network architecture diagram applicable to the communication method of the present application.
  • FIG1C is another network architecture diagram applicable to the communication method of the present application.
  • FIG1D is an example diagram of an application scenario of the communication method of the present application.
  • FIG2 is a flow chart of the communication method of the present application.
  • FIG3 is another flow chart of the communication method of the present application.
  • FIG4A is another example diagram of an application scenario of the communication method of the present application.
  • FIG4B is another example diagram of an application scenario of the communication method of the present application.
  • FIG5 is another flow chart of the communication method of the present application.
  • FIG6A is another example diagram of an application scenario of the communication method of the present application.
  • FIG6B is another example diagram of an application scenario of the communication method of the present application.
  • FIG7 is another flow chart of the communication method of the present application.
  • FIG8 is another flow chart of the communication method of the present application.
  • FIG9 is a schematic diagram of an embodiment of a communication device in the present application.
  • FIG10 is a schematic diagram of another embodiment of a communication device in the present application.
  • FIG11 is a schematic diagram of another embodiment of a communication device in the present application.
  • FIG. 12 is a schematic diagram of another embodiment of a communication device in the present application.
  • the communication method proposed in this application can be applied to the long term evolution (LTE) system, the 5G NR (5G New Radio) system, the 6th generation mobile communication technology (6G) system and subsequent evolution standards, and this application does not limit this.
  • LTE long term evolution
  • 5G NR 5G New Radio
  • 6G 6th generation mobile communication technology
  • the communication system includes at least a terminal device, an access network device and a core network device.
  • the terminal device includes a device that provides voice and/or data connectivity to the user.
  • it may include a handheld device with a wireless connection function or a processing device connected to a wireless modem.
  • the terminal device can communicate with a core network (e.g., a 5G core network (5th generation core, 5GC)) via a radio access network (RAN) and can exchange voice and/or data with the RAN.
  • a core network e.g., a 5G core network (5th generation core, 5GC)
  • RAN radio access network
  • the terminal device may also be referred to as a terminal, user equipment (UE), wireless terminal device, mobile terminal (MT) device, subscriber unit, subscriber station, mobile station (MS), mobile station (mobile), remote station (remote station), access point (AP), remote terminal device (remote terminal), access terminal device (access terminal), user terminal device (user terminal), user agent (user agent), or user equipment (user device), etc.
  • UE user equipment
  • MT mobile terminal
  • MS mobile station
  • mobile mobile station
  • remote station remote station
  • access point AP
  • remote terminal device remote terminal device
  • access terminal device access terminal
  • user terminal device user terminal
  • user agent user agent
  • user equipment user device
  • the terminal device may be a mobile phone, a tablet computer, a computer with wireless transceiver function, a virtual reality (VR) terminal device, an augmented reality (AR) terminal device, a wireless terminal in industrial control, a wireless terminal in self-driving, a wireless terminal in remote medical surgery, a wireless terminal in smart grid, a wireless terminal in transportation safety, a wireless terminal in smart city, a wireless terminal in smart home, etc.
  • VR virtual reality
  • AR augmented reality
  • the terminal device in the present application may be any of the above-mentioned devices or chips, which are not specifically limited here. Whether as a device or as a chip, the terminal device can be manufactured, sold or used as an independent product. In this embodiment and subsequent embodiments, the terminal device is taken as an example for introduction.
  • the access network device may be any device with wireless transceiver function, and may be used to be responsible for air interface related functions, such as wireless link maintenance function, wireless resource management function, and some mobility management functions.
  • the access network device may also be configured with a baseband unit (BBU) with baseband signal processing function.
  • BBU baseband unit
  • the access network device may be the access network device (radio access network, RAN) that currently provides services for the terminal device.
  • NB Node B
  • eNB evolved Node B
  • gNB next generation Node B
  • NR new radio
  • node e.g., xNodeB
  • TRP transmission reception point
  • RNC radio network controller
  • BSC base station controller
  • BTS base transceiver station
  • HNB home Node B
  • the access network equipment may be a device including a centralized unit (CU) (also called a control unit) and/or a distributed unit (DU).
  • CU centralized unit
  • DU distributed unit
  • the RAN equipment including CU and DU splits the protocol layer of the gNB in the NR system, and the functions of some protocol layers are placed in the central control of CU, and the functions of the remaining part or all of the protocol layers are distributed in DU, and DU is centrally controlled by CU.
  • the access network device in the embodiment of the present application can be any of the above-mentioned devices or chips in the above-mentioned devices, and the specific details are not limited here. Whether as a device or as a chip, the access network device can be manufactured, sold or used as an independent product. In this embodiment and subsequent embodiments, the access network device is taken as an example for introduction. In NTN, the access network device may include satellites and NTN gateways.
  • the access network device when the access network device is composed of CU and DU, multiple DUs can share one CU.
  • Protocol stack segmentation For example, as shown in Figure 1A, one possible approach is to deploy the radio resource control (RRC), service data adaptation protocol (SDAP) and packet data convergence protocol (PDCP) layers in the CU, and the remaining radio link control (RLC) layers, media access control (MAC) layers and physical (PHY) layers in the DU.
  • RRC radio resource control
  • SDAP service data adaptation protocol
  • PDCP packet data convergence protocol
  • RLC radio link control
  • MAC media access control
  • PHY physical
  • the CU represents the gNB connected to the core network via the NG interface
  • the CU represents the gNB connected to other gNBs via the Xn interface
  • the CU can also represent the gNB connected to other eNBs via the X2 port to perform dual connection operations.
  • the CU can also be divided into a control plane (CU-CP) and a user plane (CU-UP).
  • the CU-CP is responsible for the control plane functions, mainly including RRC and PDCP (i.e., PDCP-C) corresponding to the control plane.
  • PDCP-C is mainly responsible for encryption and decryption of control plane data, integrity protection, and data transmission.
  • CU-UP is responsible for user plane functions, mainly including SDAP and PDCP corresponding to the user plane (ie PDCP-U).
  • SDAP is mainly responsible for processing the data of the core network and mapping the flow to the bearer.
  • PDCP-U is mainly responsible for encryption and decryption, integrity protection, header compression, sequence number maintenance and data transmission of the data plane.
  • CU-CP and CU-UP are connected through the E1 interface.
  • CU-CP represents the gNB connected to the core network through the NG interface, and connected to the DU through the F1 interface control plane (ie F1-C).
  • CU-UP is connected to the DU through the F1 interface user plane (ie F1-U).
  • PDCP-C is also in CU-UP.
  • the control plane CU-CP of the CU also includes a further segmentation architecture, that is, the existing CU-CP is further divided into CU-CP1 and CU-CP2.
  • CU-CP1 includes various wireless resource management functions (for example, mobility management, specific values of various information in the downlink RRC message sent to the terminal device, etc.), and
  • CU-CP2 only includes RRC functions (for example, responsible for generating downlink RRC messages and decoding uplink RRC messages) and PDCP-C functions (that is, the basic functions of control plane signaling at the PDCP layer).
  • Core network equipment refers to equipment in the core network (CN) that provides service support for terminal equipment.
  • core network equipment includes access and mobility management function (AMF) entity, session management function (SMF) entity, user plane function (UPF) entity, etc., which are not listed here one by one.
  • AMF access and mobility management function
  • SMF session management function
  • UPF user plane function
  • the AMF entity can be responsible for access management and mobility management of terminal equipment
  • the SMF entity can be responsible for session management, such as user session establishment
  • the UPF entity can be a functional entity of the user plane, mainly responsible for connecting to the external network.
  • the entity in this application can also be referred to as a network element or a functional entity.
  • the AMF entity can also be referred to as an AMF network element or an AMF functional entity; for another example, the SMF entity can also be referred to as an SMF network element or an SMF functional entity, etc.
  • the core network equipment in this application includes at least an AMF entity.
  • the communication method proposed in the present application can be applied to the non-terrestrial communication network NTN architecture.
  • the non-terrestrial communication network based on the NG-RAN architecture (NTN-based NG-RAN architectures) defined in the 3GPP protocol.
  • NTN-based NG-RAN architectures NTN-based NG-RAN architectures
  • some or all of the functions of the aforementioned access network device can be implemented by a non-terrestrial communication network device (for example, at least one of a satellite, a tethered unmanned aerial system (TUA), a lighter than air drone (LTA), a heavier than air drone (HTA), and a high altitude platform station (HAPS)); or, the access network device provides services to the terminal device through the non-terrestrial communication network device.
  • TAA unmanned aerial system
  • LTA lighter than air drone
  • HTA heavier than air drone
  • HAPS high altitude platform station
  • non-terrestrial communication network device as a satellite as an example, but the present application is not limited.
  • the non-terrestrial communication network device may also be any of the above, that is, the satellite described in the present invention may also be replaced by any of the above non-terrestrial communication network devices.
  • This application can be applied to the NG-RAN architecture based on regenerative satellite.
  • the following will introduce several common examples of NG-RAN architecture based on regenerative satellite:
  • FIG. 1B an example of the NG-RAN architecture of a regenerative satellite without an inter-satellite link (ISL) (also referred to as an intersatellite link) is shown.
  • the satellite serves as an access network device or has the function of an access network device.
  • the terminal device sends a Uu wireless interface signal to the access network device (i.e., the satellite) through a service link between the satellite and the satellite; accordingly, the satellite receives the Uu wireless interface signal from the terminal device as an access network device and parses and processes the received signal.
  • the access network device i.e., the satellite
  • the satellite receives the Uu wireless interface signal from the terminal device as an access network device and parses and processes the received signal.
  • the satellite exchanges information with the ground NTN gateway through a feeder link, and then the satellite exchanges NG port information with the ground core network device through the ground NTN gateway.
  • the satellite generates NG port information and sends the NG port information to the core network device through the ground NTN gateway.
  • the core network device generates NG port information and sends the NG port information to the satellite through the ground NTN gateway.
  • the satellite generates the following signals: signals of the Uu radio interface and signals of the satellite radio interface (SRI) on the feeder link between the NTN gateway and the satellite.
  • SRI satellite radio interface
  • FIG1C an example of a RAN architecture of a regenerative satellite with an ISL is shown.
  • the satellite serves as an access network device or has the function of an access network device.
  • the ground terminal device, the satellite The relationship between the NTN gateway and the core network device is similar to the example shown in FIG. 1B , except that an inter-satellite link exists between the two satellites in the example shown in FIG. 1C , and Xn port information can be exchanged through the inter-satellite link.
  • the satellite as an access network device can exchange Uu interface signaling with the ground terminal device through the service link, and may also need to exchange NG interface signaling with the core network device through the ground NTN gateway.
  • the satellite when the ground corresponding to the area where the satellite is located is not deployed with an NTN gateway, the satellite cannot or cannot successfully establish a connection with the core network through the NTN gateway.
  • the satellite cell may have two states: 1) The system message broadcast by the satellite indicates that the cell state is a cell that cannot provide services (for example, the cell barred state indicated by the system message is the barred state), and the terminal device cannot access the satellite (that is, the satellite that has not established a connection with the core network device), and the terminal device cannot enjoy network services. 2) The system message broadcast by the satellite indicates that the cell state is a cell that can provide services (for example, the cell barred state indicated by the system message is the not barred state), but the terminal device does not perceive that the satellite has not established a connection with the core network, so the terminal device may access the satellite.
  • the system message broadcast by the satellite indicates that the cell state is a cell that cannot provide services (for example, the cell barred state indicated by the system message is the not barred state), but the terminal device does not perceive that the satellite has not established a connection with the core network, so the terminal device may access the satellite.
  • the terminal device Since the satellite cannot or is unable to forward the access request of the terminal device to the core network device, after accessing the satellite, the terminal device cannot receive the downlink NAS message replied by the core network device and re-executes the cell measurement, cell reselection and other processes when the NAS timer times out or cannot complete the interaction required for the connection, resulting in the terminal device being in a state of searching for an accessible satellite and unable to enjoy network services.
  • the present application proposes a communication method, a communication device and a system for enabling a terminal device to obtain network services when accessing an access network device that has not been established with a core network device, without being disconnected from the network.
  • the access network device involved in this embodiment can be a non-terrestrial communication network device such as a satellite.
  • this embodiment is suitable for the NTN architecture shown in Figure 1B, that is, the RAN architecture of a regenerative satellite without an intersatellite link.
  • This embodiment can also be applied to the NTN architecture combined with Figure 1B and Figure 1C, that is, there is no continuous intersatellite link between the NTNs, but there are intersatellite links between some NTNs.
  • the first access network device, the second access network device and the terminal device will perform the following steps.
  • Step 201 A first access network device sends first indication information.
  • the terminal device receives the first indication information.
  • the first access network device broadcasts the first indication information, and the terminal device receives the first indication information from the first access network device.
  • the first indication information may be carried in a system message (e.g., system information block 1 (SIB1) or master information block (MIB), etc.).
  • SIB1 system information block 1
  • MIB master information block
  • the first access network device broadcasts a system message, and the terminal device receives the system message to obtain the aforementioned first indication information.
  • the first indication information is used to indicate that the first access network device cannot currently exchange information with the core network device. It can be understood that the first indication information is used to indicate that the first access network device cannot currently or cannot successfully establish a connection with the core network device through the NTN gateway. For example, the area where the first access network device is currently located is not covered by the NTN gateway, resulting in the first access network device currently being unable to establish a feeder link with the NTN gateway, and then the first access network device currently cannot or cannot exchange information with the core network device through the NTN gateway.
  • the NTN gateway in the area where the first access network device is currently located fails, resulting in the first access network device currently being unable to establish a feeder link with the NTN gateway, and then the first access network device currently cannot exchange information with the core network device through the NTN gateway.
  • the first indication information is used to indicate that the first access network device can currently establish a connection with the core network device through the NTN gateway, but the connection is faulty or the connection is overloaded, resulting in the first access network device being unable to exchange information with the core network device.
  • the NTN gateway in the area where the first access network device is currently located has no faults
  • the first access network device can establish a feeder link with the NTN gateway, and the NTN gateway can also establish a connection with the core network device.
  • the first access network device cannot exchange information with the core network through the NTN gateway.
  • the first indication information only indicates that the first access network device has not successfully established a connection with the core network device at present, but the first access network device has the ability to establish a connection with the core network device, and the first access network device may establish a connection with the core network device in the future. For example, when the first access network device moves to an area covered by an NTN gateway, the first access network device can establish a connection with the core network device through the NTN gateway.
  • the first indication information only indicates that the first access network device currently cannot or is unable to interact with the core network device, but the first access network device has the ability to establish a connection with the core network device, and the first access network device may establish a connection with the core network device in the future.
  • the first access network device when the first access network device moves to an area covered by an NTN gateway, the first access network device can establish a connection with the core network device through the NTN gateway.
  • the first indication information only indicates that the first access network device is currently unable or cannot exchange information with the core network device, but the first access network device has established a connection with the core network device.
  • the first access network device previously established a connection with the core network device through the NTN gateway, but when the first access network device currently moves to the area where the terminal device is located, there is no available NTN gateway in the area, but when the first access network device moves to an area where the NTN gateway is available, the first access network device can exchange information with the core network device through the NTN gateway.
  • the first indication information may be identification information describing the state of the first access network device, for example, an identification of no CN connection.
  • the first indication information may also be identification information describing a data transmission mode, for example, an identification of a store and forward mode.
  • the first access network device receives and stores signaling (e.g., NAS signaling) or data from a terminal device when it cannot exchange signaling with a core network device, and forwards the signaling or data from the terminal device to the core network device when the first access network device moves to an area where it can exchange information with the core network device.
  • This signaling transmission mode is referred to as a store and forward mode.
  • the store and forward mode also includes the first access network device receiving and storing signaling or data about the terminal device from the core network when it can exchange signaling with the core network device, and when the first access network device moves to an area that can cover the terminal device, the first access network device forwards the signaling or data about the terminal device from the core network to the terminal device.
  • Store and forward can be defined as an operation mode of the NTN access system, in which the NTN access system cannot provide a feeder link connected to the NTN gateway, but can still provide communication services to users under the access network equipment.
  • other identification information or indication information can also be used to implement the aforementioned first indication information, and this application does not limit the specific implementation form of the first indication information.
  • Step 202 The terminal device establishes a connection with the first access network device.
  • the terminal device After the terminal device receives the first indication information from the first access network device, when the terminal device needs to obtain network services, the terminal device can initiate random access to the first access network device and then establish a connection with the first access network device. Optionally, if the terminal device receives the first indication information in the first cell of the first access network device, the terminal device can initiate random access in the first cell.
  • the terminal device can initiate a four-step based random access to access the first access network device, or can initiate a two-step based random access to access the first access network device, which is not specifically limited in this application.
  • the terminal device in the process of establishing a connection with an access network device, the terminal device first performs uplink time synchronization through a random access process and then performs an RRC connection.
  • the first access network device may allocate identification information of the terminal device to the terminal device, which is used to uniquely identify the terminal device in the signaling interaction between the terminal device and the first access network device.
  • the identification information of the terminal device is a cell radio network temporary identifier (C-RNTI).
  • C-RNTI cell radio network temporary identifier
  • the first access network device will also configure the terminal device with resources used by the terminal device.
  • the aforementioned resources include but are not limited to time-frequency resources (for example, RLC resources, MAC resources and physical layer resources in the cell group configuration (CellgourpConfig) (for example, physical resources in the physical cell group configuration (PhysicalCellGroupConfig)) and resources used for uplink and downlink transmission in the special cell configuration (Spcellconfig), etc.) and bearer resources (for example, signaling radio bearer 0 (signaling radio bearer 0, SRB0), signaling radio bearer 1 (signaling radio bearer 1, SRB1) and signaling radio bearer 2 (signaling radio bearer 2, SRB2), etc.).
  • time-frequency resources for example, RLC resources, MAC resources and physical layer resources in the cell group configuration (CellgourpConfig) (for example, physical resources in the physical cell group configuration (PhysicalCellGroupConfig)) and resources used for uplink and downlink transmission in the special cell configuration (Spcellconfig), etc.
  • bearer resources for example, signaling radio bearer 0 (sign
  • RRC Setup Complete carries a NAS message (for example, the dedicated NAS-Message element in the technical specification TS 38.331 of the third generation partnership project (3GPP)).
  • the NAS message is used to transmit terminal device-specific NAS layer information between the terminal device and the core network device, and the RRC layer only transparently transmits the NAS message.
  • the NAS message sent by the terminal device to the first access network device when the RRC establishment is completed is referred to as an uplink NAS message (also referred to as an initial NAS message in some scenarios).
  • the RRC Setup Complete uplink NAS message includes a registration request (Register Request), which is used to initiate an initial registration request to the core network.
  • Step 203 The terminal device stores the context of the terminal device according to the first indication information.
  • the terminal device may execute step 203 after executing step 202, or may execute step 203 during the process of executing step 202, which is not limited here.
  • the context of the terminal device includes information related to the access stratum (AS) used when the terminal device accesses the first access network device, also known as the AS context of the terminal device.
  • the context of the terminal device includes the identification information of the terminal device configured by the first access network device for the terminal device, such as the C-RNTI configured by the first access network device; information related to the resources configured by the first access network device for the terminal device, such as the time-frequency resources configured by the first access network device for the terminal device;
  • Related information for example, cell resource configuration information (cell group configuration)
  • bearer-related information configured by the first access network device for the terminal device for example, SRB0, SRB1 related information in the radio bearer configuration (radio bear configuration), etc.
  • identification information of the cell accessed by the terminal device for example, cell global identifier (CGI), physical cell identifier (PCI), etc.
  • CGI cell global identifier
  • PCI physical cell identifier
  • the information related to AS also includes one or more of the time information when the terminal device accesses the first access network device, the geographical area information when the terminal device accesses the first access network device, and the TAC broadcast by the first access network device when the terminal device accesses the first access network device.
  • the context of the terminal device also includes information related to the non-access stratum (NAS) of the terminal device, also referred to as the NAS context of the terminal device, for example, uplink NAS messages sent by the terminal device and related NAS timers started by the terminal device.
  • NAS non-access stratum
  • the context of the terminal device also includes first indication information.
  • the context of the terminal device includes an identifier of no CN connection or an identifier of store and forward mode, indicating that the first access network device to which the terminal device is connected is currently unable to forward the NAS message of the terminal device to the core network.
  • the context of the terminal device is the context up to the time when the first access network device stops providing services.
  • the terminal device can continuously record the context of the terminal device. After the terminal device successfully accesses the first access network device, the terminal device will also continuously update the context of the terminal device until the first access network device stops providing services for the terminal device.
  • the first access network device may stop providing services for the terminal device when the terminal device cannot receive a signal from the first access network device, or after the terminal device sends an RRC Setup Complete message to the first access network device, or after the terminal device receives an RRC release message sent by the first access network device.
  • the terminal device when the first access network device stops providing services to the terminal device, if the terminal device has not received a release RRC message sent by the first access network device, or has received a release RRC message sent by the first access network device but the release RRC message carries indication information instructing the terminal device to save the context, the terminal device will continue to save the context of the terminal device.
  • the terminal device can determine that the first access network device cannot interact with the core network based on the first indication information from the first access network device, and the terminal device stores the context of the terminal device in the process of establishing a connection with the first access network device (or after establishing the connection) based on the first indication information. For example, the terminal device will continue to record the context of the terminal device from the beginning of accessing the first access network device until the first access network device stops providing services to the terminal device.
  • the context of the terminal device records the access-related information used by the terminal device when accessing the first access network device (for example, C-RNTI, SRB0 and SRB1-related information configured by the first access network device, etc.), which is conducive to the terminal device to reuse the existing access-related configuration based on the context of the terminal device to access the access network device that can provide services to the terminal device (for example, the second access network device to be introduced later), which can not only reduce the signaling overhead of the access network device to configure resources for the terminal device, but also improve the efficiency of the terminal device accessing the access network device and shorten the delay of the terminal device to establish a connection with the network side.
  • the access-related information used by the terminal device when accessing the first access network device for example, C-RNTI, SRB0 and SRB1-related information configured by the first access network device, etc.
  • Step 204 The first access network device stores the context of the terminal device.
  • the first access network device may execute step 204 after executing step 202, or may execute step 204 during the execution of step 202, which is not limited here. It should also be noted that there is no clear time sequence limitation between step 203 and step 204. For example, the terminal device first executes step 203, and then the first access network device executes step 204. For another example, the first access network device first executes step 204, and then the terminal device executes step 203. For another example, while the terminal device executes step 203, the first access network device executes step 204.
  • the context of the terminal device includes information related to the access layer AS configured for the terminal device when the terminal device accesses the first access network device; the context of the terminal device also includes information related to the non-access layer NAS sent to the first access network after the terminal device accesses the first access network device and to be transparently transmitted to the core network.
  • the context of the terminal device is the context until the first access network device stops providing services. Please refer to the relevant introduction in the previous step 203 for details, which will not be repeated here.
  • the context of the terminal device stored in the first access network device can be used when the first access network device establishes a connection with the terminal device again; it can also be sent to the core network device, and then sent by the core network device to other second access network devices that may provide services to the terminal device, for use when the second access network device establishes a connection with the terminal device.
  • the first access network device stops providing services for the terminal device. After the first access network device stops providing services for the terminal device, the terminal device can perform step 205.
  • Step 205 The terminal device establishes a connection with the second access network device based on the context of the terminal device.
  • Step 205 is an optional step.
  • the context of the terminal device is the information used by the terminal device to access the second access network device after the first access network device stops providing services to the terminal device. That is, when the first access network device stops providing services to the terminal device, the terminal device can use the context of the terminal device to establish a connection with the second access network device.
  • the second access network device is an access network device having the context of the terminal device.
  • the context of the terminal device is stored in the second access network device.
  • the context of the terminal device possessed by the second access network device is the context of the terminal device stored by the first access network device when the terminal device accesses the first access network device.
  • the second access network device is an access network device that moves to the geographical area where the terminal device is located.
  • the second access network device moves to the geographical area where the terminal device is located (also referred to as moving out of the physical area that can provide services to the terminal device), that is, when the first access network device can no longer provide services to the terminal device
  • the second access network device moves to the geographical area where the terminal device is located (also referred to as moving to the geographical area that can provide services to the terminal device), that is, when the second access network device can provide services to the terminal device
  • the terminal device can receive a system message from the second access network device, and then the terminal device can make an autonomous decision or trigger access to the second access network device under the instruction of the second access network device.
  • the second access network device and the first access network device may be the same access network device or different access network devices. They are introduced below:
  • the second access network device and the first access network device are the same access network device. For example, after the first access network device stops providing services to the terminal device for a period of time, the first access network device moves again to the geographical area where the terminal device is located, and then the terminal device establishes a connection with the first access network device again.
  • the context of the terminal device stored by the second access network device is the context of the terminal device stored by the first access network device (for example, the context of the terminal device stored by the first access network device in step 204).
  • the terminal device can trigger the establishment of a connection with the first access network device (i.e., the second access network device) by any of the following implementation methods:
  • the terminal device decides whether to trigger access to the first access network device based on the content of the system message from the first access network device. Specifically, the first access network device broadcasts the cell identification information of each cell of the first access network device in the system message, and the terminal device receives the system messages of the aforementioned cells. If the cell identification information read by the terminal device in the system message is the same as the cell identification information of the first cell stored in the context of the terminal device, the terminal device triggers access to the first cell of the first access network device.
  • the cell identification information of the first cell stored in the context of the terminal device indicates that the first cell is a cell that the terminal device has accessed before (for example, a cell that the terminal device accessed when the first access network device provided services to the terminal device).
  • the context of the terminal device may record relevant configuration information of the terminal device accessing the first cell. Therefore, the terminal device will have a higher probability of accessing the first cell based on the context of the terminal device, which is conducive to improving the efficiency of the terminal device accessing the first access network device.
  • the terminal device triggers access to the first access network device based on the indication information from the first access network device.
  • the first access network device can send a second indication information to the terminal device.
  • the second indication information is used to instruct the terminal device to initiate access, and it can also be understood that the second indication information is used to instruct the terminal device to trigger access to the first access network device.
  • the terminal device triggers access to the first access network device based on the second indication information.
  • the first access network device can send the second indication information only once, or it can periodically send the first indication information multiple times until the terminal device successfully accesses the first access network device, and this embodiment does not impose any restrictions on this.
  • the terminal device first performs downlink synchronization with the first cell of the first access network device, receives the second indication information, and triggers access to the first cell of the first access network device based on the second indication information.
  • the second indication information can be a physical downlink control channel order (PDCCH order) scrambled using the identification information of the terminal device (for example, C-RNTI or first identification information.
  • the first identification information is used to uniquely identify the terminal device in the first access network device. Specifically, the first identification information will be described in detail in step 302.4 below and will not be repeated here.), and the terminal device receives the second indication information in the first cell, then the terminal device triggers access to the first cell.
  • the first cell is a cell stored in the context of the terminal device.
  • the first access network device sends the second indication information in which cell
  • the terminal device receives the second indication information in which cell. Therefore, the terminal device may access the same cell of the first access network device twice, or may access different cells of the first access network device.
  • the terminal device after the terminal device triggers access to the first access network device based on the aforementioned implementation method 1.1 or implementation method 1.2, since the terminal device stores the context of the terminal device and the first access network device stores the context of the terminal device, the terminal device can use the AS-related information used when accessing the first access network device in the context of the terminal device to establish a connection with the first access network device again. Specifically, the terminal device initiates random access to the first cell of the first access network device for uplink synchronization. After the uplink and downlink synchronization is successful, the terminal device and the first access network device use the AS-related information in the context of the terminal device for subsequent transmission.
  • the terminal device can use the resource configuration (for example, time-frequency resource configuration and/or bearer configuration) when the terminal device last accessed the first access network device for subsequent transmission without having to re-establish the initial RRC with the first access network device.
  • the subsequent transmission can be an interactive NAS message, which can be the configuration of the interactive terminal device.
  • the terminal device directly performs subsequent NAS message transparent transmission with the first access network device.
  • the first access network device will first initiate a configuration message to the terminal device for updating the configuration in the context of the current terminal device. After the update is successful, the terminal device and the first access network device will perform subsequent NAS transparent transmission.
  • the second access network device and the first access network device are different access network devices.
  • the second access network device for example, an access network device with the same movement trajectory as the first access network device
  • the terminal device establishes a connection with the second access network device.
  • the second access network device may provide services to the terminal device immediately after the first access network device stops providing services to the terminal device, or it may provide services to the terminal device after a period of time has passed after the first access network device stops providing services to the terminal device, and there is no limitation on this.
  • the second access network device is an access network device that moves to the geographical area where the terminal device is located after the first access network device, and specifically, it is the number of access network devices that move to the geographical area where the terminal device is located after the first access network device, and there is no limitation on this.
  • the context of the terminal device stored in the second access network device comes from the first access network device. For example, after the first access network device stores the context of the terminal device, it forwards it to the second access network device through the core network device.
  • the terminal device can trigger the establishment of a connection with the second access network device through any of the following implementation methods:
  • the terminal device decides whether to trigger access to the second access network device based on the content of the system message from the second access network device.
  • the second access network device stores the context of the terminal device, and the context of the terminal device includes the cell identification information of the first cell, and the first cell is the cell that the terminal device has accessed in the first access network device.
  • the second access network device broadcasts the cell identification information of the first cell in the system message to indicate that the terminal device that has accessed the first cell triggers access to the second access network device.
  • the terminal device receives the cell identification information of the first cell in the system message of the second access network device, and the context of the terminal device stores the cell identification information of the first cell, it means that the terminal device has accessed the first cell, and the cell in the second access network device can continue to replace the first cell to provide services for the terminal device, then the terminal device triggers access to the second access network device based on the stored terminal context.
  • the terminal device accesses the second cell of the second access network device based on the cell identification information of the first cell from the second access network device.
  • the second cell is a cell in which the second access network device broadcasts the cell identification information of the first cell.
  • the second access network device broadcasts the cell identification information of the first cell in the second cell, and the terminal device receives the second indication information in the second cell and triggers access to the second cell.
  • the terminal device triggers access to the second access network device based on the indication information from the second access network device.
  • the second access network device can send a third indication information to the terminal device.
  • the third indication information is used to indicate that the terminal device initiates access, and it can also be understood that the third indication information is used to indicate that the terminal device triggers access to the second access network device.
  • the third indication information can also be used to indicate that the second access network device stores the context of the terminal device.
  • the terminal device triggers access to the second access network device based on the third indication information.
  • the second access network device can send the third indication information only once, or it can send the third indication information multiple times periodically until the terminal device successfully accesses the second access network device, and this embodiment does not limit this.
  • the terminal device triggers access to the second cell of the second access network device based on the third indication information.
  • the second access network device broadcasts the third indication information in the second cell, and the terminal device receives the third indication information in the second cell, then the terminal device triggers access to the second cell.
  • the second cell may be any cell in the second access network device.
  • the third indication information may be a physical downlink control channel command (PDCCH Order) sent to the terminal device and encrypted using identification information of the terminal device (for example, C-RNTI or first identification information); or it may be indication information of the terminal device indicating that cell identification information of the first cell is stored in the context of the terminal device.
  • the third indication information may be the cell identification information of the first cell or information indicating the first cell.
  • the third indication information sent by the second access network device may be cell identifier information of multiple cells, each cell identifier information being used to indicate a cell that a corresponding terminal device among the aforementioned multiple terminal devices has accessed.
  • the terminal device after the terminal device triggers access to the second access network device based on the aforementioned implementation 2.1 or implementation 2.2, since the terminal device stores the context of the terminal device and the second access network device stores the context of the terminal device, the terminal device can use the context of the terminal device to establish a connection with the second access network device. Specifically, the terminal device initiates random access to the second cell of the second access network device for uplink synchronization, and after the uplink and downlink synchronization is successful, the terminal device and the second access network device use the information related to the AS in the context of the terminal device for subsequent transmission.
  • the terminal device sends a random access preamble to the second access network device, and the second access network device sends a random access response to the terminal device after receiving the random access preamble from the terminal device, thereby completing uplink time synchronization between the second access network device and the terminal device. Then, the terminal device can use the information related to the time-frequency resources and the information related to the bearer in the context to determine the time-frequency resources and wireless bearers for communicating with the second access network device.
  • the terminal device can send an uplink NAS message to the second access network device based on the aforementioned time-frequency resources and wireless bearers, so that the second access network device can exchange the NAS message of the terminal device with the core network device when it is able to establish a connection with the core network device, thereby enabling the terminal device to access the network.
  • the terminal device can determine that the first access network device has not established a connection with the core network device based on the first indication information from the first access network device, and the terminal device stores the context of the terminal device based on the first indication information during the process of establishing a connection with the first access network device (or after the connection is established).
  • the context of the terminal device records the access-related information used by the terminal device when accessing the first access network device (for example, C-RNTI, SRB0 and SRB1-related information configured by the first access network device, etc.), and the terminal device can continue to use the configuration in the terminal device context (for example, the time-frequency resources and wireless bearers configured for the terminal device) to continue to communicate with the second access network device, without the need for the terminal device to re-initialize the RRC on the second access network device, so it is beneficial to save the signaling overhead of establishing a connection with the second access network device, and to improve the efficiency of the terminal device accessing the second access network device, thereby shortening the delay in establishing a connection between the terminal device and the network side.
  • the access-related information used by the terminal device when accessing the first access network device for example, C-RNTI, SRB0 and SRB1-related information configured by the first access network device, etc.
  • the terminal device can continue to use the configuration in the terminal device context (for example
  • the second access network device and the first access network device are the same access network device.
  • the first access network device provides services for the terminal device.
  • the first access network device, the terminal device and the core network device will perform the following steps.
  • Step 301 A first access network device broadcasts first indication information.
  • the terminal device receives the first indication information.
  • the first indication information please refer to the above step 201, which will not be described in detail here.
  • the first access network device broadcasts the first indication information in the first area
  • the first area is an area where the access network device cannot exchange information with the core network device.
  • the first area is an area not covered by the NTN gateway, so the first access network device cannot successfully establish a connection with the core network device through the NTN gateway in the first area.
  • the geographical area where the terminal device is located is located in the first area, that is, the geographical area where the terminal device is located is an area not covered by the NTN gateway.
  • the concept opposite to the first area is the second area.
  • the first access network device does not broadcast the first indication information in the second area.
  • the second area is an area where the access network device can exchange information with the core network device.
  • the second area is an area covered by the NTN gateway, so the first access network device can successfully establish a connection with the core network device through the NTN gateway in the second area.
  • the second area can be the first area covered by the NTN gateway that the first access network device moves to on the running track after leaving the terminal device, or it can be an area covered by the NTN gateway that is about to enter the terminal device position on the running track, which is not limited here.
  • the terminal device can receive the first indication information from the first access network device, indicating that the first access network device has not successfully established a connection with the core network device.
  • the first access network device saves the signaling from the terminal device in the first area, and waits for the first access network device to move to the second area and then forwards the signaling from the terminal device to the core network device.
  • This signaling transmission method is called Store and forward mode:
  • the terminal device that receives the first indication information may be referred to as a terminal in the store and forward mode, and the geographical area where the terminal device is located may also be referred to as a geographical area in the store and forward mode.
  • the AS of the terminal device will notify the NAS of the terminal device to take effect the first NAS timer of the terminal device or delay starting the second NAS timer of the terminal device.
  • the second NAS timer is a NAS timer used by the terminal device when the access network device (e.g., the first access network device) is able to establish a connection with the core network device; it can also be understood that the second NAS timer is a NAS timer used by the terminal device when the terminal device does not receive the first indication information from the access network device (e.g., the first access network device); it can also be understood that the second NAS timer is a NAS timer used by the terminal device when the terminal device is not in the store and forward mode; it can also be understood that the second NAS timer is a NAS timer used by the terminal device when the terminal device is not located in the geographical area of the store and forward mode.
  • the second NAS timer is a timer of the traditional NAS layer defined by the current protocol in the terrestrial network TN (e.g., TS 24.501 for 5G NAS timer).
  • the second NAS timer does not specifically refer to a single timer, and there may be different second NAS timers for different types of NAS messages.
  • the second NAS timer is T3510.
  • the terminal device sends a registration request message
  • the terminal device starts T3510; when the terminal device receives a registration reject (Registration Reject) message or a registration accept (Registration Accept) message, the terminal device stops T3510.
  • the second timer can also be a NAS timer used by other terminal devices defined by the protocol, such as T3511 and other timers, which are not listed here one by one.
  • the first NAS timer is a NAS timer used by the terminal device when the access network device (for example, the first access network device) cannot establish a connection with the core network device; it can also be understood that the first NAS timer is a NAS timer used by the terminal device when the terminal device receives the first indication information from the first access network device; it can also be understood that the first NAS timer is a NAS timer used by the terminal device when the terminal device is in the store and forward mode; it can also be understood that the first NAS timer is a NAS timer used by the terminal device when the terminal device is located in the geographical area of the store and forward mode.
  • the first NAS timer does not specifically refer to a single timer, and there may be different first NAS timers according to different types of NAS messages.
  • the NAS message is a registration request (Registration Rquest) message
  • the first NAS timer is a NAS timer corresponding to the registration request message.
  • the terminal device sends a registration request
  • the terminal device starts the first NAS timer;
  • the terminal device receives a registration reject (Registration Reject) message or a registration accept (Registration Accept) message
  • the terminal device stops the first NAS timer.
  • the first NAS timer may be a newly defined timer independent of the second NAS timer.
  • the duration of the first NAS timer is greater than the duration of the second NAS timer.
  • the first NAS timer may be a timer obtained by adding a duration offset based on the second NAS timer.
  • the second NAS timer corresponding to the registration request message is T3510
  • the first NAS timer corresponding to the registration request message may be a newly defined T3510-new dedicated to the non-terrestrial network NTN.
  • the terminal device uses T3510 during TN communication and uses T3510-new during NTN communication.
  • the first NAS timer T3510-new may be a NAS timer with a duration of 20s obtained by adding a duration offset (for example, 5s) based on the second NAS timer T3510.
  • the NAS of the terminal device takes effect on the first NAS timer, which means that when the terminal device starts the NAS timer, it starts the first NAS timer instead of starting the NAS timer in the traditional technology (for example, the second NAS timer).
  • the terminal device starts the first NAS timer when sending an uplink NAS message, instead of starting the second NAS timer when sending the uplink NAS message according to the solution of the traditional technology.
  • the terminal device delays starting the second NAS timer, which means that the terminal device does not start the second NAS timer immediately when the NAS timer should be started in the traditional technology, but starts the second NAS timer after a delay of a period of time (for example, the first period of time). For example, when the terminal device sends an uplink NAS message, the second NAS timer is started after the first period of time, instead of starting the second NAS timer immediately when the uplink NAS message is sent according to the traditional technology solution.
  • the first access network device may send the first time information to the terminal device, and correspondingly, the terminal device may also receive the first time information from the first access network device.
  • the first time information may be carried in a system message, or may be sent to the terminal device based on proprietary signaling of the terminal device, and the specific carrying form is not limited.
  • the first time information is used by the terminal device to determine the duration of the aforementioned first NAS timer or the aforementioned first duration.
  • the terminal device may convert the first time information into the duration of the first NAS timer or the aforementioned first duration according to an agreed algorithm.
  • the first time information may be the time when the first access network device arrives at the geographical area where the terminal device is located next time, or it may be the duration of the first access network device to orbit once, or it may be ephemeris information, which is not limited here.
  • ephemeris Information also called ephemeris data or ephemeris table
  • the terminal device can determine the position of the satellite based on the orbital information.
  • the ephemeris information can be represented by a two-line orbital element (TLE) format.
  • the first access network device may also broadcast the cell identification information of the first cell in the first cell, and accordingly, the terminal device may also receive the cell identification information of the first cell from the first access network device in the first cell.
  • the identification information of the first access network device may be a satellite identification.
  • the cell identification information of the first cell may be a cell global identifier (CGI), which is bound to the first access network device but not to the ground area.
  • Step 302 The terminal device establishes a connection with the first access network device.
  • the terminal device establishes a connection with a first access network device located in the first area.
  • the terminal device establishes a connection with the first access network device through the following steps:
  • Step 302.1 The terminal device sends message 1 (message 1, Msg1) to the first access network device.
  • Msg1 contains a random access preamble (RAP).
  • RAP random access preamble
  • the main function of RAP is to tell the first access network device that there is a random access request and enable the first access network device to estimate the transmission delay between the remaining terminal devices so that the first access network device can calibrate the uplink timing advance (uplink timing advance) and inform the terminal device of the calibration information through the time advance command.
  • Step 302.2 the first access network device sends message 2 (message 2, Msg2) to the terminal device.
  • the Msg2 includes a random access response (RAR), and the RAR includes a temporary cell radio network temporary identifier (T-CRNTI) and an uplink timing advance allocated by the first access network device to the terminal device.
  • RAR random access response
  • T-CRNTI temporary cell radio network temporary identifier
  • Step 302.3 the terminal device sends message 3 (message 3, Msg3) to the first access network device.
  • the Msg3 is an RRC Setup Requst message, which includes the identification information of the terminal device (for example, a temporary mobile subscription identifier (TMSI) or a random number) and an RRC establishment reason value.
  • TMSI temporary mobile subscription identifier
  • RRC establishment reason value for example, a temporary mobile subscription identifier (TMSI) or a random number
  • Step 302.4 the first access network device sends message 4 (message 4, Msg4) to the terminal device.
  • the Msg4 sent by the first access network device to the terminal device may include a contention resolution message and an RRC setup (RRC Setup) message.
  • RRC Setup configures the cell group configuration (TS 38.331, section 5.3.5.5) and the radio bearer configuration (TS 38.331 section 5.3.5.6), or the dedicated radio resource configuration (TS 36.331 section 5.3.3), and sets the cell radio network temporary identifier C-RNTI to the T-CRNTI in step 302.2.
  • the Msg4 also includes first identification information, and the first identification information is used to uniquely identify the terminal device in the first access network device. It can also be understood that the first access network device can uniquely identify the terminal device through the first identification information at different positions on the running track. In other words, no matter where the first access network device moves to on the track and how many terminal devices are connected, the first identification information can uniquely identify the aforementioned terminal device.
  • the length of the first identification information is greater than the length of the cell radio network temporary identifier C-RNTI.
  • the first access network device may also allocate first identification information to the terminal device, so that the terminal device can be uniquely identified on the first access network device, which is beneficial for the first access network device to find the context of the terminal device through the first identification information when it arrives at the geographical area where the terminal device is located next time.
  • Step 302.5 the terminal device sends message 5 (message 5, Msg5) to the first access network device.
  • the Msg5 is an RRC Setup Complete message
  • the Msg5 carries an uplink NAS message (for example, the uplink NAS message at the time of initial access is a Registration Request message).
  • the terminal device When the terminal device carries an uplink NAS message in the sent Msg5, the terminal device immediately starts the first NAS timer based on the type of the uplink NAS message, or starts the second NAS timer after the first duration.
  • the processing method is the same as that after the second NAS timer times out. For details on the method after the NAS timer of the 5G system times out, see TS 24.501, section 10.2.
  • the terminal device after the terminal device sends Msg5, or during the operation of the first NAS timer or the second NAS timer, the terminal device will be in a new RRC state, which is different from the RRC idle state, RRC inactive state and RRC connected state in the traditional technology.
  • the new RRC state is referred to as the first state hereinafter. It should be understood that the "first state" is only an example of the title listed for the convenience of introduction, and this application does not limit the title of the RRC state.
  • the terminal device in the first state, maintains the context of the terminal device (for example, the context of the terminal device stored in step 303), and the terminal device can perform cell measurement, perform cell downlink synchronization, and read system messages, but will not trigger the radio link failure (RLF) process, and will not trigger the RRC reconstruction process.
  • the terminal entering the first state can temporarily turn off the physical layer search and detection signal functions after the first access network device stops the service, and wait until the first access network device reaches the geographical area where the terminal device is located again or before it reaches it (for example, the terminal device can determine when the first access network device arrives through the first time information), and then the terminal device can turn on the physical layer search and detection signal functions.
  • the terminal device in the first state, maintains the context of the terminal device (for example, the context of the terminal device stored in step 303), and before the first access network device reaches the area that can cover the terminal device again, the terminal device does not perform cell measurement, cell downlink synchronization, and reading of system messages.
  • the terminal device performs cell measurement, cell downlink synchronization, and reading of system messages), but does not trigger a radio link failure (RLF) process, and does not trigger an RRC reconstruction process.
  • RLF radio link failure
  • the terminal device when the terminal device enters the first state, the terminal device can first turn off functions such as physical layer search and detection signals, and wait until the first access network device reaches the geographical area where the terminal device is located again or before it reaches it (for example, the terminal device can determine when the first access network device arrives through the first time information), and then turn on functions such as physical layer search and detection signals.
  • functions such as physical layer search and detection signals
  • the terminal device entering the first state will not trigger the wireless connection failure RLF process, and will not trigger the RRC reconstruction process, it is beneficial for the terminal device to reuse the existing RRC connection-related configurations and save the signaling overhead for reestablishing the RRC connection.
  • the terminal device can temporarily turn off functions such as physical layer search and detection signals in the first state, it is beneficial to save energy consumption of the terminal device.
  • the terminal device when the terminal device initiates to establish a connection with the first access network device again, the terminal device exits the first state.
  • Step 303 The terminal device stores the context of the terminal device according to the first indication information.
  • the context of the terminal device includes information related to the access layer AS used when the terminal device accesses the first access network device, also referred to as the AS context of the terminal device.
  • the AS context of the terminal device includes the cell identifier of the serving cell. For example, if the terminal device accesses the first cell of the first access network device, the cell identifier of the serving cell is the cell identifier of the first cell.
  • the AS context of the terminal device also includes the identification information of the terminal device.
  • the identification information of the terminal device may be the C-RNTI configured by the first access network device for the terminal device.
  • the identification information of the terminal device may also be the first identification information.
  • the AS context of the terminal device also includes information related to the time-frequency resources configured by the first access network device for the terminal device (for example, cell resource configuration information (cell group configuration)) and information related to the bearer configured by the first access network device for the terminal device (for example, information related to SRB0 and SRB1 in the radio bearer configuration (radio bear configuration), etc.).
  • the context of the terminal device also includes information related to the non-access stratum (NAS) of the terminal device, also known as the NAS context of the terminal device.
  • NAS non-access stratum
  • uplink NAS messages sent by the terminal device relevant NAS timers started by the terminal device, selected PLMN-Identity, information related to registered core network devices (for example, registered AMF), etc.
  • the terminal device may execute step 303 after executing step 302, or may execute step 303 during the process of executing step 302, which is not limited here.
  • the terminal device when the terminal device starts to access the first access network device, the terminal device can continuously record the context of the terminal device. After the terminal device successfully accesses the first access network device, the terminal device will also continuously update the context of the terminal device until the first access network device stops providing services for the terminal device. For example, when the first access network device initiates Msg1, the terminal device records at least one of the following: the cell identification information of the first cell, the public land mobile network (PLMN), and the TAC; after sending Msg3, the terminal device records the identification information of the terminal device (for example, TC-RNTI) and the RRC establishment reason in the context of the terminal device. Value.
  • PLMN public land mobile network
  • TAC the terminal device records the identification information of the terminal device (for example, TC-RNTI) and the RRC establishment reason in the context of the terminal device. Value.
  • the terminal device After receiving Msg4, the terminal device records SRB1-related information, C-RNTI and/or first identification information in the context of the terminal device. For another example, after sending Msg5, the terminal device records the uplink NAS message sent by the terminal device or records the indication information of the uplink NAS sent, as well as the selected PLMN identification carried in Msg5, the information related to the registered core network device, etc.
  • the terminal device since the terminal device can determine that the first access network device cannot successfully establish a connection with the core network device based on the first indication information received from the first access network device, when the terminal device accesses the first access network device, the terminal device will continue to record the context of the terminal device from the beginning of accessing the first access network device until the first access network device stops providing services to the terminal device. After the first access network device stops providing services to the terminal device, the terminal device saves the context until the first access network re-initiates access, and the terminal device updates the context according to the configuration of the first access network device; when the terminal device reselects another network and initiates access due to failure to access the first access network device, the terminal device deletes the aforementioned context.
  • the context of the terminal device records the access-related information used by the terminal device when accessing the first access network device (for example, C-RNTI, first identification information, and SRB1-related information configured by the first access network device, etc.). This is beneficial for the terminal device to quickly access the first access network device when the first access network device moves to the geographical area where the terminal device is located again.
  • the access-related information used by the terminal device for example, C-RNTI, first identification information, and SRB1-related information configured by the first access network device, etc.
  • Step 304 The first access network device stores the context of the terminal device.
  • step 303 and step 304 there is no clear time sequence for step 303 and step 304.
  • the terminal device first executes step 303, and then the first access network device executes step 304.
  • the first access network device first executes step 304, and then the terminal device executes step 303.
  • the first access network device executes step 304 while the terminal device executes step 303.
  • the context of the terminal device includes information related to the access layer AS used when the terminal device accesses the first access network device, also referred to as the AS context of the terminal device.
  • the AS context of the terminal device includes the cell identifier of the serving cell, the identifier information of the terminal device (including the first identifier information and/or C-RNTI), and the information related to the time-frequency resources configured by the first access network device for the terminal device (including cell resource configuration information (cell group configuration) and radio bearer configuration (radio bear configuration)).
  • cell resource configuration information cell group configuration
  • radio bearer configuration radio bear configuration
  • the AS context of the terminal device also includes the geographical area information when the terminal device accesses the first access network device and/or the time information when the terminal device accesses the first access network device.
  • the geographical area information of the terminal device is used to indicate the geographical area where the terminal device is located (for example, the geographical area where the terminal device is located when the terminal device accesses the first access network device).
  • the geographical area can be a physical area represented by longitude and latitude, or it can be a TAC area (for example, an area indicated by TAC, or an area indicated by PLMN and TAC).
  • the context of the terminal device also includes information related to NAS, also known as the NAS context of the terminal device.
  • NAS also known as the NAS context of the terminal device.
  • the uplink NAS message sent by the terminal device the relevant NAS timer started by the terminal device, the selected PLMN-Identity, the information related to the registered core network device (for example, registered AMF), etc.
  • the first access network device after receiving Msg3 from the terminal device, the first access network device establishes the context of the terminal device and records information related to the access layer AS until the first access network device stops providing services to the terminal device. For example, the first access network device obtains the identification information (e.g., TMSI or random number) and RRC establishment reason value of the terminal device in Msg3, and records the identification information (e.g., TMSI or random number) and RRC establishment reason value of the terminal device in the context of the terminal device. Then, the first access network device performs admission and resource allocation of SRB1 resources, and records SRB1-related information in the context of the terminal device.
  • the identification information e.g., TMSI or random number
  • RRC establishment reason value e.g., TMSI or random number
  • the first access network device performs admission and resource allocation of SRB1 resources, and records SRB1-related information in the context of the terminal device.
  • the first access network device after the first access network device allocates C-RNTI and/or first identification information to the terminal device through Msg4, the first access network device records C-RNTI and/or first identification information in the context of the terminal device. For another example, the first access network device records the geographical area information of the terminal device and/or the time information of the terminal device accessing the first access network device after the terminal device accesses.
  • Step 305 The first access network device moves from the first area to the second area.
  • the first access network device stops providing services for the terminal device. At this time, the terminal device is still in the first state.
  • the first access network device can successfully establish a connection with the core network device in the second area (for example, an S1/NG connection) (or, the first access network device can exchange information with the core network device in the second area), and then, the first access network device exchanges NAS signaling of the terminal device with the core network device.
  • the first access network device and the core network device will execute steps 306 and 307 in sequence.
  • Step 306 The first access network device sends an uplink NAS message to the core network device.
  • the core network device receives an uplink NAS message from the first access network device.
  • the first uplink NAS message received by the first access network device from the terminal device can be carried in the initial message (Initial UE Message) and forwarded to the core network.
  • the first access network device sends an Initial UE Message containing a registration request (Register Request) message to the core network device, and accordingly, the core network device receives the initial message of the terminal device from the first access network device to obtain an uplink NAS message.
  • Registration Request Registration request
  • the first access network device sends fourth indication information to the core network device, and the fourth indication information is used to indicate that the terminal device accesses the first access network device when the first access network device cannot exchange information with the core network device.
  • the fourth indication information may indicate that the terminal device dynamically accesses between the core network and the access network device or performs a dynamic connection between the core network and the access network device (for an explanation of the dynamic connection, please refer to the relevant introduction in step 701 below).
  • the fourth indication information is information indicating that the terminal device is in store and forward mode (the terminal device being in store and forward mode can also be referred to as the terminal device accessing through the access network device in store and forward mode).
  • the fourth indication information may also be implemented using information indicating the mode of the geographical area where the terminal device is located, for example, the fourth indication information is information indicating that the geographical area where the terminal device is located is a geographical area in store and forward mode.
  • the core network device uses the fourth indication information to validate the first NAS timer of the core network device or delay starting the second NAS timer of the core network device.
  • the second NAS timer is a NAS timer used by the core network device when the access network device (for example, the first access network device) is able to establish a connection with the core network device; it can also be understood that the second NAS timer is a NAS timer used by the core network device when the core network device does not receive the fourth indication information from the access network device; it can also be understood that the second NAS timer is a NAS timer used by the core network device when the terminal device is not in the store and forward mode; it can also be understood that the second NAS timer is a NAS timer used by the core network device when the terminal device is not located in the geographical area of the store and forward mode.
  • the second NAS timer is a timer of the traditional NAS layer defined by the current protocol in the terrestrial network TN (for example, TS24.501 for 5G NAS timer).
  • the second NAS timer does not specifically refer to a single timer, and there may be different second NAS timers for different types of NAS messages.
  • the NAS message is an authentication request (Authentication Rquest) message
  • the second NAS timer is T3460.
  • the core network device sends an authentication request message
  • the core network device starts T3460; when the core network device receives an authentication response (Authentication Response) message, the core network device stops T3460.
  • the second NAS timer is T3470.
  • the core network device When the core network device sends an identity request message, the core network device starts T3470; when the core network device receives an identity response (Identity Response) message, the core network device stops T3470.
  • the second timer can also be a NAS timer used by other core network devices defined by the protocol, which will not be listed here one by one.
  • the first NAS timer is a NAS timer used by the core network device when the access network device (for example, the first access network device) cannot establish a connection with the core network device; it can also be understood that the first NAS timer is a NAS timer used by the core network device when the core network device receives the fourth indication information from the first access network device; it can also be understood that the first NAS timer is a NAS timer used by the core network device when the terminal device is in the store and forward mode; it can also be understood that the first NAS timer is a NAS timer used by the core network device when the terminal device is located in the geographical area of the store and forward mode.
  • the first NAS timer does not specifically refer to a single timer, and there may be different first NAS timers according to different types of NAS messages.
  • the NAS message is an authentication request (Authentication Rquest) message
  • the first NAS timer is a NAS timer corresponding to the authentication request message.
  • the core network device sends an authentication request
  • the core network device starts the first NAS timer;
  • the core network device receives an authentication response (Authentication Response) message
  • the core network device stops the first NAS timer.
  • the first NAS timer may be a newly defined timer independent of the second NAS timer.
  • the duration of the first NAS timer is greater than the duration of the second NAS timer.
  • the first NAS timer may be a timer obtained by adding a duration offset based on the second NAS timer.
  • the second NAS timer corresponding to the authentication request message is T3460
  • the first NAS timer corresponding to the authentication request message may be a newly defined T3460-new dedicated to the non-terrestrial network NTN.
  • the core network device uses T3460 during TN communication and uses T3460-new during NTN communication.
  • the first NAS timer T3460-new may be a NAS timer with a duration of 15s obtained by adding a duration offset (for example, 5s) based on the second NAS timer T3460.
  • the core network device takes effect on the first NAS timer, which means that when the core network device starts the NAS timer, it starts the first NAS timer instead of starting the NAS timer in the traditional technology (for example, the second NAS timer).
  • the device starts the first NAS timer when sending a downlink NAS message, instead of starting the second NAS timer when sending a downlink NAS message according to the solution of the traditional technology.
  • the core network device delays starting the second NAS timer, which means that the core network device does not start the second NAS timer immediately when the NAS timer should be started in the traditional technology, but starts the second NAS timer after a delay of a period of time (for example, the first period of time). For example, when the core network device sends a downlink NAS message, it starts the second NAS timer after the first period of time, instead of starting the second NAS timer immediately when the downlink NAS message is sent according to the traditional technology solution.
  • the first access network device may also send the first time information to the core network device, and accordingly, the core network device may also receive the first time information from the first access network device.
  • the core network device may also receive the first time information from the first access network device.
  • the fourth indication information and/or the first time information can be carried in the initial message of the terminal device and sent to the core network device, or can be carried in other messages and sent to the core network device, which is not limited here.
  • Step 307 The core network device sends a downlink NAS message to the first access network device.
  • the first access network device receives a downlink NAS message from the core network device.
  • the core network device When the core network device sends a downlink NAS message to the first access network device, the core network device immediately starts the first NAS timer, or starts the second NAS timer after the first duration.
  • the core network device can send multiple downlink NAS messages to the first access network device currently located in the second area. For example, the core network device sends a downlink NAS message for authentication, a downlink NAS message for encryption, and a downlink NAS message for registration to the first access network device. The core network device can also send a downlink NAS message to the first access network device currently located in the second area, and then send another downlink NAS message to the first access network device when the first access network device moves to the second area again.
  • the core network device first sends a downlink NAS message for authentication to the first access network device currently located in the second area, and then sends a downlink NAS message for NAS encryption to the first access network device when the first access network device moves to the second area again, and then sends a downlink NAS message of registration acceptance to the first access network device when the first access network device moves to the second area again.
  • Step 308 The first access network device stores the downlink NAS message of the terminal device.
  • the first access network device After the first access network device receives the downlink NAS message from the core network device, the first access network device stores the downlink NAS message of the terminal device in correspondence with the context of the terminal device. Since the first access network device has not yet established a connection with the terminal device, the first access network device will not immediately send the downlink NAS message.
  • Step 309 The first access network device moves from the second area to the first area.
  • the first access network device Since the geographical area where the terminal device is located is in the first area, after the first access network device moves to the first area, the first access network device will trigger the terminal device to execute step 311 through step 310a or step 310b, that is, the first access network device will trigger the terminal device to initiate access to the first access network device through step 310a or step 310b.
  • first area in step 309 and the first area in steps 301 to 305 may be different physical areas or the same physical area.
  • the first area in step 309 and the first area in steps 301 to 305 both include the physical area where the terminal device is located.
  • Step 310a The first access network device broadcasts the cell identification information of the first cell.
  • the terminal device receives the cell identification information of the first cell from the first access network device.
  • the cell identification information of the first cell may be carried in a system message.
  • the first access network device will broadcast the cell identification information of each cell of the first access network device in a system message, and the terminal device may receive the aforementioned system message containing the cell identification information of each cell. If the cell identification information received by the terminal device in the system message is the same as the cell identification information of the first cell stored in the context of the terminal device, the terminal device triggers access to the cell.
  • the context of the terminal device may record relevant configuration information of the terminal device accessing the first cell. Therefore, the terminal device will have a higher probability of accessing the first cell based on the context of the terminal device, which is conducive to improving the efficiency of the terminal device accessing the first access network device.
  • Step 310b The first access network device broadcasts second indication information.
  • the terminal device receives second indication information from the first access network device.
  • the second indication information is used to instruct the terminal device to initiate access, which can also be understood as the second indication information is used to instruct the terminal device to trigger access to the first access network device.
  • the second indication information is a physical downlink control channel order (PDCCH order).
  • the terminal device triggers access to the first cell of the first access network device based on the second indication information.
  • the first access network device broadcasts the second indication information in the first cell, and the terminal device receives the second indication information in the first cell, then the terminal device triggers access to the first cell.
  • the first cell is a cell stored in the context of the terminal device.
  • the terminal device receives the second indication information in the cell in which the first access network device broadcasts the second indication information, which triggers the access to the cell. Therefore, the terminal device may access the same cell of the first access network device twice, or may access different cells of the first access network device.
  • Step 311 The terminal device establishes a connection with the first access network device based on the context of the terminal device.
  • the terminal device Since the terminal device stores the context of the terminal device, the first access network device also stores the context of the terminal device, and the context of the terminal device includes the AS configuration information of the terminal device, the terminal device and the first access network device only need to perform uplink synchronization to reuse the AS configuration information in the context to establish a connection.
  • the terminal device may first perform uplink and downlink synchronization with the first access network device, and then continue to use the configuration in the context of the terminal device to further communicate with the first access network device, so that the first access network device can communicate with the first access network device based on the time-frequency resources and/or wireless bearer resources configured in the context of the terminal device, without the need for the first access network device to re-execute the RRC initial establishment.
  • the terminal device establishes a connection with the first access network device through the following steps:
  • Step 311.1 The terminal device sends Msg1 to the first access network device.
  • Msg1 includes a random access preamble (RAP), which may be carried in the PDCCH order or broadcast in the system message. If the RAP is carried in the PDCCH order, the RAP is allocated to the terminal device by the first access network device, and the RAP can be used for non-contention random access; if the RAP is in the random access configuration broadcast in the system message, the terminal device randomly selects the random access preamble, and the terminal device can perform contention-based random access.
  • RAP random access preamble
  • Step 311.2 The first access network device sends Msg2 to the terminal device.
  • the Msg2 includes the random access response RAR, the temporary cell radio network temporary identifier T-CRNTI allocated by the first access network device to the terminal device, and the uplink timing advance.
  • Step 312 The terminal device sends identification information of the terminal device to the first access network device.
  • the identification information of the terminal device is the C-RNTI and/or first identification information stored in the context of the terminal device.
  • the terminal device may send a C-RNTI MAC CE to the first access network device, where the C-RNTI is the C-RNTI allocated when the terminal device first accesses the first access network device and is stored in the terminal device.
  • the first access network device configures the first identification information for the terminal device in step 302, and the first identification information is stored in the context of the terminal device, and the terminal device sends the first identification information to the first access network device.
  • Step 313 The first access network device determines the context of the terminal device based on the identification information of the terminal device.
  • the first access network device determines the context of the terminal device in different ways. The following are introduced respectively:
  • the first access network device receives the first identification information from the terminal device, and the first access network device determines the context of the terminal device based on the first identification information. Since the first identification information can uniquely identify the terminal device on the first access network device, the first access network device can accurately search for the context of the terminal device based on the first identification information.
  • the first access network device receives from the terminal device a cell wireless network temporary identifier.
  • the context of the terminal device stored in the first access network device includes the geographical area information when the terminal device accesses the first access network device and/or the time information when the terminal device accesses the first access network device
  • the first access network device determines the context of the terminal device based on the geographical area information when the terminal device accesses the first access network device and/or the time information when the terminal device accesses the first access network device, and the cell wireless network temporary identifier.
  • the context of the terminal device stored in the first access network device includes the access The geographical area information when the terminal device accesses the first access network device, the first access network device determines the context of the terminal device based on the geographical area information when the terminal device accesses the first access network device and the cell wireless network temporary identifier.
  • the context of the terminal device stored in the first access network device includes time information when the terminal device accesses the first access network device, and the first access network device determines the context of the terminal device based on the time information when the terminal device accesses the first access network device and the cell wireless network temporary identifier.
  • the context of the terminal device stored in the first access network device includes the geographical area information when the terminal device accesses the first access network device and the time information when the terminal device accesses the first access network device.
  • the first access network device determines the context of the terminal device based on the geographical area information of the terminal device, the time information when the terminal device accesses the first access network device, and the cell wireless network temporary identifier.
  • the first access network device and the terminal device may continue to exchange NAS messages.
  • Step 314 The first access network device determines a downlink NAS message of the terminal device based on the context of the terminal device.
  • the first access network device may determine multiple downlink NAS messages of the terminal device based on the context of the terminal device, or may determine only one downlink NAS message of the terminal device based on the context of the terminal device.
  • the number of downlink NAS messages of the terminal device determined by the first access network device based on the context of the terminal device is the same as the number of downlink NAS messages received by the first access network device from the core network device in the second area.
  • Step 315 The first access network device forwards the downlink NAS message to the terminal device.
  • the first access network device will also update the NAS-related information in the context of the terminal device (i.e., the NAS context of the terminal device). For example, the first access network device stores the downlink NAS message forwarded to the terminal device in the context of the terminal device, or the first access network device stores an indication information to indicate which downlink NAS message the first access network device forwarded to the terminal device.
  • Step 316 The terminal device sends an uplink NAS message to the first access network device.
  • the uplink NAS message may be a message corresponding to the downlink NAS message in step 315.
  • the uplink NAS message is a response message of the downlink NAS message.
  • the uplink NAS message may be an authentication response (Authentication Response) message.
  • the downlink NAS message is a security mode command (Security Mode Command) message
  • the uplink NAS message may be a security mode complete (Security Mode Complete) message.
  • the downlink NAS message is a registration acceptance (Register Accept) message
  • the uplink NAS message may be a registration complete (Register Complete) message.
  • the uplink NAS message can also be a process message triggered by the NAS layer of the terminal device. For example, after the initial access is completed, when a packet data unit (PDU) bearer needs to be established, the uplink NAS message is a bearer establishment request (PDU session establishment request) message.
  • PDU packet data unit
  • Step 317 The first access network device stores the uplink NAS message of the terminal device.
  • the first access network device stores the received uplink NAS message in the terminal device context.
  • the first access network device establishes a mapping relationship between the received uplink NAS message and the terminal device context, so that the first access network device can query the uplink NAS message that needs to be transparently transmitted to the core network device according to the context of the terminal device.
  • Step 318 The first access network device moves from the first area to the second area.
  • the first access network device After the first access network device moves to the second area, the first access network device successfully establishes a connection with the core network device.
  • the second area in step 318 and the second area in steps 305 to 309 may be different physical areas or the same physical area.
  • the second area in step 318 and the second area in steps 305 to 309 of the first access network device can both exchange information with the core network device.
  • the second area in step 318 and the second area in steps 305 to 309 both have at least one NTN gateway that enables the first access network device to establish a connection with the core network device and exchange information.
  • Step 319 The first access network device sends an uplink NAS message to the core network device.
  • the first access network device determines that the core network device is the core network device stored in the context of the terminal device, the first access network device forwards the uplink NAS message to the core network device.
  • the core network device will continue to communicate with the terminal device through the first access network device.
  • Interactive NAS signaling Exemplarily, the core network device also sends the next downlink NAS message to the first access network device, and the first access network device stores the received downlink NAS message.
  • the first access network device After the first access network device moves to the first area, the first access network device establishes a connection with the terminal device, and sends the stored downlink NAS message to the terminal device, and receives the terminal device's reply uplink NAS message from the terminal device, and stores the uplink NAS message.
  • the first access network device After the first access network device moves to the second area, the first access network device establishes a connection with the core network device, and sends the stored uplink NAS message to the core network device.
  • the specific process is similar to steps 307 to 319 and will not be repeated here.
  • the solution of this embodiment is introduced by taking Figures 4A and 4B as examples.
  • the first access network device when the first access network device is located in the first area (for example, an area not covered by the NTN gateway), the first access network device notifies the terminal device through the first indication information that the first access network device has not established a connection with the core network device.
  • the terminal device and the first access network device can both store the context of the terminal device, and the first access network device also stores the initial NAS message received from the terminal device (i.e., the uplink NAS message carried in Msg5, for example, the registration request message).
  • the first access network device moves along the running track from the first area to the second area (for example, an area covered by the NTN gateway).
  • the first access network device located in the second area establishes a connection with the core network device, sends an initial NAS message to the core network device through the NTN gateway, and receives a downlink NAS message 1 from the core network device through the NTN gateway.
  • the first access network device quickly establishes a connection with the terminal device based on the context of the stored terminal device.
  • the first access network device After the connection is established, the first access network device sends a downlink NAS message 1 to the terminal device, and the terminal device replies to the first access network device with an uplink NAS message 1 in response to the downlink NAS message 1.
  • the first access network device stops providing services to the terminal device, the first access network device moves from the first area to the second area (for example, an area covered by an NTN gateway) again.
  • the first access network device located in the second area establishes a connection with the core network device again, and sends an uplink NAS message 1 to the core network device through the NTN gateway.
  • the first access network device can continue to interact NAS signaling in a similar manner. Through multiple NAS signaling interactions, NAS registration between the terminal device and the core network is successful, and then the terminal device can obtain network services.
  • both the terminal device and the first access network device can store the context of the terminal device to retain the configuration information (for example, time-frequency resources, wireless bearer and other configuration information) used when the terminal device accesses the first access network device, when the first access network device arrives at the geographical area where the terminal device is located again, the terminal device and the first access network device can quickly complete uplink and downlink synchronization based on the context of the terminal device and continue to exchange NAS signaling, without the need for the terminal device to re-initialize RRC at the first access network device. Therefore, it is not only beneficial to save the signaling overhead of establishing a connection with the first access network device, but also beneficial to improve the efficiency of the terminal device accessing the first access network device.
  • the configuration information for example, time-frequency resources, wireless bearer and other configuration information
  • the first access network device can quickly accept the terminal device and continue to exchange NAS signaling with the terminal device each time it arrives at the geographical area where the terminal device is located, it is beneficial to quickly exchange NAS signaling through the first access network device to complete the registration process of the terminal device on the core network side, thereby enabling terminal devices located in areas not covered by the NTN gateway to obtain network services.
  • the second access network device and the first access network device are different access network devices.
  • the first access network device and the second access network device can provide services to the terminal device at different times.
  • the first access network device, the second access network device, the terminal device and the core network device will perform the following steps.
  • Step 501 A first access network device broadcasts first indication information.
  • the terminal device receives the first indication information.
  • Step 502 The terminal device establishes a connection with the first access network device.
  • the terminal device after the terminal device sends Msg5, or during the operation of the first NAS timer or the second NAS timer, the terminal device will be in a new RRC state, which is different from the RRC idle state, RRC inactive state and RRC connected state in the traditional technology.
  • the new RRC state is referred to as the second state hereinafter. It should be understood that the "second state" is only an example of the title listed for the convenience of introduction, and this application does not limit the title of the RRC state.
  • the terminal device in the second state, maintains the context of the terminal device (for example, the context of the terminal device stored in step 503), and the terminal device can perform cell measurement, perform cell downlink synchronization, and read system messages, but will not trigger the radio link failure (RLF) process and will not trigger the RRC reconstruction process.
  • the terminal entering the second state can temporarily disable the physical layer search and detection signal functions after the first access network device stops serving, and wait until the second access network device is available again.
  • the terminal device starts functions such as physical layer search and signal detection.
  • the terminal device in the second state, maintains the context of the terminal device (for example, the context of the terminal device stored in step 503), and before the second access network device reaches the area that can cover the terminal device again, the terminal device does not perform cell measurement, cell downlink synchronization, and reading of system messages.
  • the terminal device performs cell measurement, cell downlink synchronization, and reading of system messages), but does not trigger a radio link failure (RLF) process, and does not trigger an RRC reconstruction process.
  • RLF radio link failure
  • the terminal device when the terminal device enters the second state, the terminal device can first turn off functions such as physical layer search and detection signals, and wait until the second access network device reaches the geographical area where the terminal device is located again or before it reaches it (for example, the terminal device can determine when the second access network device arrives through the first time information), and then turn on functions such as physical layer search and detection signals.
  • functions such as physical layer search and detection signals
  • the terminal device entering the second state will not trigger the wireless connection failure RLF process, and will not trigger the RRC reconstruction process, it is beneficial for the terminal device to reuse the existing RRC connection-related configurations and save the signaling overhead for reestablishing the RRC connection.
  • the terminal device can temporarily turn off functions such as physical layer search and detection signals in the second state, it is beneficial to save energy consumption of the terminal device.
  • the terminal device when the terminal device initiates to establish a connection with the second access network device again, the terminal device exits the second state.
  • Step 503 The terminal device stores the context of the terminal device according to the first indication information.
  • Step 504 The first access network device stores the context of the terminal device.
  • step 503 there is no clear time sequence for step 503 and step 504.
  • the terminal device first executes step 503, and then the first access network device executes step 504.
  • the first access network device first executes step 504, and then the terminal device executes step 503.
  • the first access network device executes step 504 while the terminal device executes step 503.
  • Step 505 The first access network device moves from the first area to the second area.
  • the first access network device When the first access network device moves to the second area (ie, the area where the first access network device can exchange information with the core network device), the first access network device can establish a connection with the core network device through the NTN gateway and exchange information.
  • steps 501 to 505 are similar to steps 301 to 305 in the corresponding embodiment of FIG. 3 .
  • steps 501 to 505 are similar to steps 301 to 305 in the corresponding embodiment of FIG. 3 .
  • steps 501 to 505 are similar to steps 301 to 305 in the corresponding embodiment of FIG. 3 .
  • Step 506 The first access network device sends an uplink NAS message and the context of the terminal device to the core network device.
  • the core network device receives an uplink NAS message and the context of the terminal device from the first access network device.
  • the context of the terminal device is used to establish a connection between the second access network device determined by the core network device and the terminal device.
  • the context of the terminal device is used to establish a connection between the second access network device determined by the core network device and the terminal device.
  • the first access network device can send an uplink NAS message and the context of the terminal device to the core network device through one message.
  • the first access network device carries the uplink NAS message and the context of the terminal device in the initial message (Initial UE Message) of the terminal device and sends it to the core network device.
  • the first access network device can also send an uplink NAS message and the context of the terminal device to the core network device through two different messages.
  • the first access network device carries the uplink NAS message in the initial message (Initial UE Message) of the terminal device and sends it to the core network device, and carries the context of the terminal device in other messages and sends them to the core network device.
  • the first access network device sends a fourth indication message to the core network device, and the fourth indication message is used to indicate that the terminal device is accessing the first access network device when the first access network device cannot interact with the core network device.
  • the core network device activates the first NAS timer or delays starting the second NAS timer based on the fourth indication message.
  • the first access network device may also send the first time information to the core network device, and accordingly, the core network device may also receive the first time information from the first access network device.
  • the core network device may also receive the first time information from the first access network device.
  • At least one of the fourth indication information, the first time information and the context of the terminal device can be carried in the initial message of the terminal device and sent to the core network device, or can be carried in other messages and sent to the core network device, which is not limited here.
  • Step 507 The core network device sends a downlink NAS message and the context of the terminal device to the second access network device.
  • the second access network device receives the downlink NAS message and the context of the terminal device from the core network device.
  • the core network device determines the second access network device, and then the core network device sends a downlink NAS message and the context of the terminal device to the second access network device.
  • the core network device can determine the second access network device based on the context of the terminal device and the running track information of each access network device. Since the context of the terminal device includes the geographical location information of the terminal device, and the core network device knows the running track information of each access network device, the core network device can determine that the access network device whose running track passes through the geographical area where the terminal device is located is the second access network device based on the geographical location information of the terminal device and the running track information of each access network device.
  • the second access network device can be an access network device with the same running track as the first access network device.
  • the core network device may determine the second access network device based only on the track information of each access network device without considering the context of the terminal device. For example, the core network device determines an access network device that has the same running track as the first access network device and runs after the first access network device as the second access network device.
  • the core network device When the core network device sends a downlink NAS message to the second access network device, the core network device immediately starts the first NAS timer, or starts the second NAS timer after the first duration.
  • the core network device For the introduction of the fourth information, please refer to the relevant description in the above step 306, which will not be repeated here.
  • the second access network device when the core network device sends a downlink NAS message and the context of the terminal device to the second access network device, the second access network device has moved to the second area, that is, the area where the second access network device can interact with the core network device.
  • the core network device can send multiple downlink NAS messages to the second access network device currently located in the second area, and the core network device can also send a downlink NAS message to the second access network device currently located in the second area, which is not limited here.
  • the second area to which the first access network device moves in step 505 and the second area where the second access network device is located in step 507 may be different physical areas or the same physical area.
  • the second area of the first access network device in step 505 and the second area of the second access network device in step 507 can both exchange information with the core network device.
  • the first access network device and the second access network device establish a connection with the core network device through the same NTN gateway, and the first access network device and the second access network device are both located in the physical area provided by the same NTN gateway.
  • the second area to which the first access network device moves in step 505 and the second area where the second access network device is located in step 507 are the same physical area, that is, both are areas provided with services by the NTN gateway.
  • the first access network device and the second access network device establish a connection with the core network device through different NTN gateways.
  • the first access network device establishes a connection with the core network device through NTN gateway 1 and exchanges information
  • the second access network device establishes a connection with the core network device through NTN gateway 2 and exchanges information. If the physical area provided by NTN gateway 1 is different from the physical area provided by NTN gateway 2, then the second area to which the first access network device moves in step 505 is a different physical area from the second area where the second access network device is located in step 507, that is, the areas provided with services by two different NTN gateways respectively.
  • Step 508 The second access network device stores the downlink NAS message of the terminal device and the context of the terminal device.
  • the second access network device After the second access network device receives the downlink NAS message from the core network device and the context of the terminal device, the second access network device stores the downlink NAS message of the terminal device and the context of the terminal device in correspondence. Since the second access network device has not yet established a connection with the terminal device at this time, the second access network device will not immediately send the downlink NAS message.
  • Step 509 The second access network device moves from the second area to the first area.
  • the second access network device Since the second access network device receives the context of the terminal device from the core network device, and the context of the terminal device contains the geographical area information of the terminal device, the geographical area information can indicate the geographical area where the terminal device is located. Therefore, the second access network device can determine the geographical area where the terminal device is located based on the geographical area information in the context of the terminal device. Since the geographical area where the terminal device is located is located in the first area, when the second access network device moves to the first area and moves to the geographical area where the terminal device is located, the second access network device will trigger the terminal device to execute step 511 through step 510a or step 510b, that is, the second access network device will trigger the terminal device to initiate access to the second access network device through step 510a or step 510b.
  • first area in step 509 and the first area in steps 501 to 505 may be different geographical areas or the same geographical area.
  • the first area in step 509 and the first area in steps 501 to 505 both include the geographical area where the terminal device is located.
  • Step 510a The second access network device broadcasts the cell identification information of the first cell.
  • the terminal device receives the cell identification information of the first cell from the second access network device.
  • the cell identification information of the first cell may be carried in a system message.
  • the second access network device broadcasts the cell identification information of the first cell in a system message, and if the terminal device receives the cell identification information of the first cell in the system message, and the context of the terminal device stores the cell identification information of the first cell, the terminal device triggers access to the second access network device.
  • Step 510b The second access network device sends third indication information.
  • the terminal device receives third indication information from the second access network device.
  • the third indication information is used to instruct the terminal device to initiate access, and it can also be understood that the third indication information is used to instruct the terminal device to trigger access to the second access network device.
  • the third indication information can be a physical downlink control channel command (PDCCH Order) sent to the terminal device and encrypted with the identification information of the terminal device (for example, C-RNTI or first identification information); it can also be indication information of a terminal device that stores the cell identification information of the first cell in the context of the terminal device.
  • the third indication information can be the cell identification information of the first cell or information indicating the first cell.
  • the terminal device triggers access to the second cell of the second access network device based on the third indication information.
  • the second access network device broadcasts the third indication information in the second cell, and the terminal device receives the third indication information in the second cell, then the terminal device triggers access to the second cell.
  • the second cell can be any cell in the second access network device.
  • Step 511 The terminal device establishes a connection with the second access network device based on the context of the terminal device.
  • the second access network device Since the terminal device stores the context of the terminal device, the second access network device also stores the context of the terminal device, and the context of the terminal device includes the AS configuration information of the terminal device, the terminal device and the second access network device only need to perform uplink synchronization to reuse the AS configuration information in the context to establish a connection.
  • the terminal device may first perform uplink and downlink synchronization with the second access network device, and then continue to use the configuration in the context of the terminal device to further communicate with the second access network device, so that the second access network device can communicate with the second access network device based on the time-frequency resources and/or wireless bearer resources configured in the context of the terminal device, without the need for the second access network device to re-execute the RRC initial establishment.
  • the terminal device establishes a connection with the second access network device through the following steps:
  • Step 511.1 The terminal device sends Msg1 to the second access network device.
  • Msg1 includes a random access preamble (RAP), which may be carried in the PDCCH order or broadcast in the system message. If the RAP is carried in the PDCCH order, the RAP is allocated to the terminal device by the first access network device, and the RAP can be used for non-contention random access; if the RAP is in the random access configuration broadcast in the system message, the terminal device randomly selects the random access preamble, and the terminal device can perform contention-based random access.
  • RAP random access preamble
  • Step 511.2 The second access network device sends Msg2 to the terminal device.
  • the Msg2 includes the random access response RAR, the temporary cell radio network temporary identifier T-CRNTI allocated by the second access network device to the terminal device, and the uplink timing advance.
  • Step 512 The terminal device sends identification information of the terminal device to the second access network device.
  • the identification information of the terminal device is the C-RNTI and/or first identification information stored in the context of the terminal device.
  • the terminal device may send a C-RNTI MAC CE to the second access network device, where the C-RNTI is the C-RNTI allocated when the terminal device first accesses the first access network device and is stored in the terminal device.
  • the first access network device configures the first identification information for the terminal device in step 302, and the first identification information is stored in the context of the terminal device, and the terminal device sends the first identification information to the second access network device.
  • Step 513 The second access network device determines the context of the terminal device based on the identification information of the terminal device.
  • the second access network device determines the context of the terminal device in different ways. The following are introduced respectively:
  • what the second access network device receives from the terminal device is the first identification information
  • the second access network device determines the context of the terminal device based on the first identification information
  • the second access network device receives from the terminal device a cell wireless network temporary identifier.
  • the context of the terminal device stored in the access network device includes the geographical area information of the terminal device and/or the time information of the terminal device accessing the first access network device
  • the second access network device determines the context of the terminal device based on the geographical area information of the terminal device and/or the time information of the terminal device accessing the first access network device, and the cell wireless network temporary identifier.
  • the context of the terminal device stored in the second access network device includes geographic area information of the terminal device, and the second access network device determines the context of the terminal device based on the geographic area information of the terminal device and the cell wireless network temporary identifier.
  • the context of the terminal device stored in the second access network device includes time information when the terminal device accesses the first access network device, and the second access network device determines the context of the terminal device based on the time information when the terminal device accesses the first access network device and the cell wireless network temporary identifier.
  • the context of the terminal device stored in the second access network device includes the geographical area information of the terminal device and the time information of the terminal device accessing the first access network device, and the second access network device determines the context of the terminal device based on the geographical area information of the terminal device, the time information of the terminal device accessing the first access network device and the cell wireless network temporary identifier.
  • the first access network device and the terminal device may continue to exchange NAS messages.
  • Step 514 The second access network device determines a downlink NAS message of the terminal device based on the context of the terminal device.
  • the second access network device may determine multiple downlink NAS messages of the terminal device based on the context of the terminal device, or may determine only one downlink NAS message of the terminal device based on the context of the terminal device.
  • the number of downlink NAS messages of the terminal device determined by the second access network device based on the context of the terminal device is the same as the number of downlink NAS messages received by the second access network device from the core network device in the second area.
  • Step 515 The second access network device forwards the downlink NAS message to the terminal device.
  • the second access network device will also update the NAS-related information in the context of the terminal device (i.e., the NAS context of the terminal device). For example, the second access network device stores the downlink NAS message forwarded to the terminal device in the context of the terminal device, or the second access network device stores an indication information to indicate which downlink NAS message the second access network device has forwarded to the terminal device.
  • Step 516 The terminal device sends an uplink NAS message to the second access network device.
  • the uplink NAS message may be a message corresponding to the downlink NAS message in step 315.
  • the uplink NAS message is a response message to the downlink NAS message. The details are similar to the above step 316 and will not be described in detail here.
  • Step 517 The second access network device stores the uplink NAS message of the terminal device.
  • the second access network device stores the received uplink NAS message in the terminal device context.
  • the second access network device establishes a mapping relationship between the received uplink NAS message and the terminal device context, so that the second access network device can query the uplink NAS message that needs to be transparently transmitted to the core network device according to the context of the terminal device.
  • Step 518 The second access network device moves from the first area to the second area.
  • the second access network device After the second access network device moves to the second area, the second access network device establishes a connection with the core network device.
  • the second area reached by the second access network device in step 518 and the second area reached by the first access network device in step 505 may be the same physical area or different physical areas. Please refer to the introduction of the relevant example in step 507 for details, which will not be repeated here.
  • the second area reached by the second access network device in step 518 and the second area reached by the second access network device in step 507 may be the same physical area or different physical areas.
  • the second access network device establishes a connection with the core network device through the same NTN gateway twice, and the second access network device is located in the physical area provided by the same NTN gateway twice.
  • the second area to which the second access network device moves in step 507 and the second area to which the second access network device moves in step 518 are the same physical area, that is, both are areas provided with services by the NTN gateway.
  • the second access network device establishes a connection with the core network device twice through different NTN gateways.
  • the second access network device establishes a connection with the core network device through NTN gateway a and exchanges information; in step 518, the second access network device establishes a connection with the core network device through NTN gateway b and exchanges information.
  • the second area to which the second access network device moves in step 507 is different from the second area to which the second access network device moves in step 518, that is, the areas provided with services by two different NTN gateways respectively.
  • NTN gateway a is the last NTN gateway searched before the second access network device is about to provide services to the terminal device
  • NTN gateway b is the first NTN gateway searched after the second access network device stops providing services to the terminal device.
  • Step 519 The second access network device sends an uplink NAS message and the context of the terminal device to the core network device.
  • the core network device receives the uplink NAS message and the context of the terminal device from the second access network device.
  • the core network device will determine another second access network device to continue to exchange NAS signaling with the terminal device.
  • the second access network device in step 519 is called the second access network device #1
  • the second access network device determined by the core network device after step 519 is called the second access network device #2.
  • the core network device After the core network device receives the uplink NAS message and the context of the terminal device from the second access network device #1, the core network device determines another second access network device #2 on the running track that can pass through the geographical area where the terminal device is located based on the context of the terminal device, and then sends the next downlink NAS message and the context of the terminal device to the second access network device #2, and the second access network device #2 stores the received downlink NAS message and the context of the terminal device.
  • the second access network device #2 After the second access network device #2 moves to the geographical location where the terminal device is located in the first area, the second access network device #2 establishes a connection with the terminal device, sends the stored downlink NAS message to the terminal device, and receives the uplink NAS message replied by the terminal device from the terminal device, and stores the uplink NAS message.
  • the second access network device #2 moves to the second area again, the second access network device #2 establishes a connection with the core network device again and sends the stored uplink NAS message to the core network device.
  • the specific process is similar to steps 507 to 519 and will not be described in detail here.
  • the solution of this embodiment is introduced by taking FIG. 6A and FIG. 6B as examples.
  • the first access network device informs the terminal device through the first indication information that the first access network device has not established a connection with the core network device.
  • the terminal device and the first access network device can both store the context of the terminal device, and the first access network device also stores the initial NAS message received from the terminal device (i.e., the uplink NAS message carried in Msg5, for example, the registration request message).
  • the first access network device moves from the first area to the second area (for example, an area covered by the NTN gateway) along the running track.
  • the first access network device located in the second area establishes a connection with the core network device, and sends the initial NAS message and the context of the terminal device to the core network device through the NTN gateway, so that the core network device determines the second access network device #1.
  • the core network device sends a downlink NAS message 1 to the second access network device #1 through the NTN gateway.
  • the second access network device #1 when the second access network device #1 moves to the first area (including the geographical area where the terminal device is located), the second access network device #1 quickly establishes a connection with the terminal device based on the context of the terminal device received from the core network device. After the connection is established, the second access network device #1 sends a downlink NAS message 1 to the terminal device, and the terminal device replies to the first access network device with an uplink NAS message 1 in response to the downlink NAS message 1. After the second access network device #1 stops providing services to the terminal device, the second access network device #1 moves again from the first area to the second area (for example, an area covered by an NTN gateway).
  • the first area for example, an area covered by an NTN gateway
  • the second access network device #1 located in the second area establishes a connection with the core network device again, and sends an uplink NAS message 1 to the core network device through the NTN gateway.
  • the core network device can determine the second access network device #2, and send a downlink NAS message 2 and the context of the terminal device to the second access network device #2 through the NTN gateway, so that the second access network device #2 continues to interact with NAS signaling in a similar manner to the second access network device #1.
  • NAS signaling interactions NAS registration between the terminal device and the core network is successful, and the terminal device can then obtain network services.
  • both the terminal device and the first access network device can store the context of the terminal device to retain the configuration information (for example, time-frequency resources, wireless bearer and other configuration information) used when the terminal device accesses the first access network device, and the first access network device can also forward the context of the terminal device to the core network device, so that when the first access network device stops providing services for the terminal device, the core network device can select the second access network device for the terminal device to continue to provide services for the terminal device.
  • the configuration information for example, time-frequency resources, wireless bearer and other configuration information
  • the terminal device and the second access network device can quickly complete the uplink and downlink synchronization based on the context of the terminal device and continue to exchange NAS signaling, without the need for the terminal device to re-initialize RRC in the second access network device. Therefore, it is not only beneficial to save the signaling overhead of establishing a connection with the second access network device, but also beneficial to improve the efficiency of the terminal device accessing the second access network device.
  • the second access network device will also send the updated context of the terminal device to the core network device, so that the core network device continues to provide services for the terminal device through the next second access network device. Because each Every time the context device with the terminal device arrives at the geographical area where the terminal device is located, it can quickly accept the terminal device and continue to exchange NAS signaling with the terminal device. Therefore, it is beneficial to quickly exchange NAS signaling through the second access network device to complete the registration process of the terminal device on the core network side, which is beneficial to improve communication efficiency and enable terminal devices located in areas not covered by NTN gateways to obtain network services.
  • the core network device can page the terminal device based on the method introduced in Figure 7. It should be noted that the terminal device can complete registration in the core network device by the method provided in any of the embodiments corresponding to Figures 2, 3 or 5, or can complete registration in the core network device by other methods in traditional technologies, which is not limited in this embodiment. Specifically, the core network device, the access network device and the terminal device will perform the following steps.
  • Step 701 The core network device determines at least one access network device according to the geographical area information of the terminal device.
  • the core network device After the terminal device is registered with the core network device, the core network device stores the context of the terminal device, and the context of the terminal device includes the geographical area information of the terminal device, and the geographical area information of the terminal device is used to indicate the geographical area where the terminal device is located.
  • the core network device needs to initiate paging to the terminal device, the core network device determines at least one access network device based on the geographical area information of the terminal device stored in the core network device, and the at least one access network device is used to page the terminal device (i.e., the terminal device located in the geographical area indicated by the geographical area information).
  • the mobile path of the coverage area of each access network device in at least one access network device can pass through the geographical area where the terminal device is located. It can also be understood that the access network device determined by the core network device is an access network device that can be moved to the geographical area where the terminal device is located in the future.
  • the access network device determined by the core network device may be an access network device that can currently establish a connection with the core network device through the NTN gateway, or an access network device that cannot currently establish a connection with the core network device through the NTN gateway but will be able to establish a connection or exchange information with the core network device through the NTN gateway in the future.
  • the access network device determined by the core network device may be an access network device that can currently establish a connection with the core network device through the NTN gateway or exchange information with the core network device, then generally the current coverage area of the access network device does not include the geographical area where the terminal device is located.
  • the core network device determined by the core network device may be an access network device that cannot currently establish a connection with the core network device through the NTN gateway or exchange information with the core network device, then the core network device will also wait until the access network device can establish a connection with the core network device through the NTN gateway or exchange information with the core network device, and then the core network device will send some information (such as a paging message) to the access network device.
  • the geographical area information of the terminal device may be a tracking area TAC, or it may be a geographical area represented by longitude and latitude.
  • the geographical area information of the terminal device may also be a tracking area list (tracking area list, TAL) described in the tracking area TAC where the terminal device is currently located.
  • the geographical area of the terminal is a logical concept, which is mainly used to select paging access network devices for the core network.
  • the geographical area information can be the PLMN+TAC when the terminal device accesses.
  • the core network determines the access network device whose next running trajectory will pass through the area where the terminal device is located as the access network device used to paging the terminal device based on the PLMN+TAC.
  • the core network device may determine one access network device, or it may determine multiple access network devices in order to improve the paging success rate. Among them, the multiple access network devices determined by the core network device may be selected at the same time, or they may be selected multiple times in succession, which is not limited here.
  • each of the at least one access network device determined by the core network device can be moved to the area indicated by TAC1 (that is, these access network devices can provide services for the area indicated by TAC1), but the aforementioned access network device may not be in the area indicated by TAC1 when currently establishing a connection with the core network device.
  • access network device 1 when access network device 1 is currently connected to the core network device, it is located in the area indicated by TAC2, but the access network device 1 will be able to operate to the area indicated by TAC1 in the future.
  • the core network device receives fourth indication information during the terminal device registration phase, or the context of the terminal device stored in the core network device includes fourth indication information
  • the fourth indication information is used to indicate that the terminal device is accessing the first access network device when the first access network device cannot interact with the core network device.
  • the core network device can trigger paging of the terminal device in the manner provided in this embodiment based on the fourth indication information.
  • the core network device determines the access network device used to paging the terminal device from the tracking area TA list of the terminal device according to traditional technology. For example, the core network device initiates paging to all access network devices in the TA list.
  • the core network device has preconfigured TAC list information, and the preconfigured TAC list information is used to indicate that the terminal devices in the TAC list can only be connected to the core network device and the access network device in a dynamic connection manner.
  • dynamic connection refers to the scenario where the link between the access network device and the NTN gateway or core network is not always present or available, and the information sent by the terminal device to the core network device needs to be first stored by the access network device, and then connected to the core network device and forwarded to the core network device after the access network device has run along the track for a period of time.
  • the opposite of dynamic connection is static connection.
  • Static connection means that in the scenario where the link between the access network device and the NTN gateway or core network is always present or available, the information sent by the terminal device to the core network device can be directly forwarded by the access network device without the need to be stored first and then forwarded.
  • the preconfigured TAC list information can be configured in the core network device, or it can be uniformly managed in operations, administration and maintenance (OAM) and sent to the core network device by OAM.
  • OAM operations, administration and maintenance
  • the specific preconfiguration form is not limited.
  • Step 702 The core network device sends a paging message to at least one access network device.
  • the core network device when the core network device sends a paging message, the core network device starts a first paging timer.
  • the first paging timer is the paging timer used by the core network device when the terminal device is in the store and forward mode; it can also be understood that the first paging timer is the paging timer used by the core network device when the terminal device is located in the geographical area of the store and forward mode; it can also be understood that the first paging timer is the paging timer used by the core network device when it receives the fourth indication information from the access network device.
  • the core network device starts the preconfigured paging timer when sending the paging message.
  • the duration of the first paging timer is greater than the duration of the preconfigured paging timer.
  • the duration of the preconfigured paging timer can be configured by the network management device or predefined by the protocol, which is not limited here.
  • the core network device If the core network device can receive the response message of the terminal device during the operation of the first paging timer, the core network device successfully pages the terminal device; if the core network device does not receive the response message of the terminal device during the operation of the first paging timer, the core network device fails to page the terminal device. According to the existing paging process, a paging retry process can be performed later.
  • the access network device receives a paging message from the core network device.
  • the paging message includes the geographical area information of the terminal device. Since the geographical area indicated by the geographical area information of the terminal device is inconsistent with the geographical area where the access network device receives the paging message, the access network device will store the paging message received from the core network device instead of sending the paging message immediately.
  • the access network device 1 receives a paging message from the core network device in the area indicated by TAC1, then the access network device stores the paging message instead of immediately taking it offline.
  • Step 703 at least one access network device moves to the geographical area where the terminal device is located.
  • At least one access network device may arrive at the geographical area where the terminal device is located at different times, or two or more access network devices may arrive at the geographical area where the terminal device is located at the same time, which is not limited here.
  • the at least one access network device includes a third access network device and a fourth access network device
  • the fourth access network device is an access network device that provides services to the terminal device after the third access network device stops providing services to the terminal device, that is, the third access network device arrives at the geographical area where the terminal device is located earlier than the fourth access network device.
  • the third access network device is the first access network device among the at least one access network device to arrive at the geographical area where the terminal device is located
  • the fourth access network device is the second access network device among the at least one access network device to arrive at the geographical area where the terminal device is located.
  • Step 704 at least one access network device sends a paging message in the geographical area where the terminal device is located.
  • the terminal device receives a paging message from at least one access network device.
  • each access network device in at least one access network device when each access network device in at least one access network device arrives at the geographical area where the terminal device is located, each access network device sends a paging message in the geographical area where the terminal device is located. For example, when the third access network device moves to the geographical area where the terminal device is located, the third access network device sends a paging message in the geographical area where the terminal device is located; when the fourth access network device moves to the geographical area where the terminal device is located, the fourth access network device sends a paging message in the geographical area where the terminal device is located.
  • the terminal device upon receiving the first paging message (for example, a paging message from a third access network device), the terminal device After receiving the paging message, the terminal device processes the paging message, and before the paging message processing is completed or before responding to the paging message (for example, from receiving the first paging message to the terminal device triggering access to the wireless network), no subsequent paging messages are received or processed.
  • the first paging message for example, a paging message from a third access network device
  • the terminal device processes the paging message, and before the paging message processing is completed or before responding to the paging message (for example, from receiving the first paging message to the terminal device triggering access to the wireless network).
  • the AS of the terminal device if the AS of the terminal device receives a paging message, the AS of the terminal device notifies the NAS of the terminal device so that the NAS of the terminal device processes the paging message. After the NAS of the terminal device starts processing the paging message, the NAS of the terminal device notifies the AS of the terminal device not to monitor other paging messages. Since the number of times the terminal device receives paging messages can be reduced, it is beneficial to save energy consumption of the terminal device.
  • the AS of the terminal device if the AS of the terminal device receives a paging message, the AS of the terminal device notifies the NAS of the terminal device so that the NAS of the terminal device processes the paging message. After the NAS of the terminal device starts to process the paging message, the NAS of the terminal device no longer receives the paging message from the AS of the terminal device, and the AS of the terminal device no longer forwards the paging message to the NAS of the terminal device even if it receives the paging message. Since the number of times the terminal device processes the paging message can be reduced, it is beneficial to save the energy consumption of the terminal device.
  • only some of the at least one access network device broadcasts a paging message when arriving at the geographical area where the terminal device is located. For example, when the third access network device moves to the geographical area where the terminal device is located, the third access network device sends a paging message in the geographical area where the terminal device is located; when the fourth access network device moves to the geographical area where the terminal device is located, the fourth access network device does not send a paging message.
  • the fourth access network device continues to page the terminal device; when the third access network device successfully pages the terminal device, the third access network device sends a fifth indication message to the fourth access network device, and the fifth indication message is used to instruct the fourth access network device to delete the paging message used to paging the terminal device or to indicate that the fourth access network device does not need to page the terminal device.
  • the third access network device can also indicate the identifier of the terminal device to the fourth access network device, so that the fourth access network device can know the terminal device corresponding to the fifth indication message, that is, which terminal devices' paging messages are deleted or which terminal devices do not need to be paged. Since it can reduce unnecessary paging overhead of the fourth access network device, it is beneficial to reduce signaling overhead in the entire network.
  • the core network device can determine at least one access network device for paging the terminal device based on the geographical area information of the terminal device, rather than directly determining the access network device for paging the terminal device based on the TA list, which is beneficial to improving the probability of the core network device successfully paging the terminal device.
  • the core network device can send data based on the method described in Figure 8. It should be noted that the terminal device can complete registration in the core network device by the method provided in any of the embodiments corresponding to Figures 2, 3 or 5, or can complete registration in the core network device by other methods, which is not limited by this embodiment. Specifically, the core network device, the access network device and the terminal device will perform the following steps.
  • Step 801 The core network device sends multiple data packets of the terminal device to the fifth access network device, each data packet corresponding to a first serial number.
  • the fifth access network device receives multiple data packets from the terminal device from the core network device, and each data packet corresponds to a first serial number.
  • the fifth access network device is an access network device determined by the core network device for forwarding downlink data to the terminal device.
  • the core network device stores the context of the terminal device, and the core network device can determine the access network device for forwarding downlink data to the terminal device based on the context of the terminal device.
  • the context of the terminal device includes the geographical area information of the terminal device.
  • the core network device determines at least one access network device based on the geographical area information of the terminal device, and the at least one access network device is used to forward downlink data to the terminal device.
  • the current coverage area of each access network device does not include the geographical area where the terminal device is located, and the mobile path of the coverage area of the access network device passes through the geographical area where the terminal device is located. Specifically, please refer to the previous step 701, which will not be repeated here.
  • At least one access network device includes a fifth access network device.
  • the fifth access network device is the first access network device among the at least one access network device to reach the geographical area where the terminal device is located. It should be noted that the fifth access network device and the first access network device in the embodiment corresponding to FIG. 3 or FIG. 5 may be the same access network device, or may be a different access network device.
  • the fifth access network device is used as an example for introduction below.
  • each of the aforementioned multiple data packets corresponds to a first serial number
  • the first serial number is generated by the core network device.
  • the first sequence number may be a GPRS tunneling protocol user plane serial number (GTPU SN), or may be other sequence numbers used to mark data packets, which are not limited here. It should be noted that each data packet sent by the core network device carries the first sequence number corresponding to the data packet.
  • the fifth access network device sends the context of the terminal device to the core network device, wherein the context of the terminal device includes information related to AS (ie, AS context) and information related to NAS (ie, NAS context).
  • AS ie, AS context
  • NAS ie, NAS context
  • the AS context of the terminal device includes identification information of the terminal device (for example, C-RNTI configured by the access network device when the terminal device initially accesses the network, etc.), resource-related information configured by the access network device for the terminal device (for example, cell resource configuration information (cell group configuration) and radio bearer configuration (radio bear configuration)), identification information of the cell accessed by the terminal device (for example, cell global identifier (CGI), physical cell identifier (PCI), etc.), and other information related to the Uu port.
  • identification information of the terminal device for example, C-RNTI configured by the access network device when the terminal device initially accesses the network, etc.
  • resource-related information configured by the access network device for the terminal device
  • cell resource configuration information for the terminal device
  • radio bearer configuration radio bearer configuration
  • identification information of the cell accessed by the terminal device for example, cell global identifier (CGI), physical cell identifier (PCI), etc.
  • CGI cell global identifier
  • PCI physical cell identifier
  • the NAS context of the terminal device includes uplink NAS messages sent by the terminal device, relevant NAS timers that the terminal device has started, status information of the terminal device, security-related information, capability information of the terminal device, IMSI and other NG port information related to the core network.
  • Step 802 The fifth access network device moves to the geographical area where the terminal device is located.
  • Step 803 The fifth access network device sends a data packet carrying the first serial number and/or the second serial number to the terminal device.
  • the terminal device receives a data packet carrying the first sequence number and/or the second sequence number from the fifth access network device.
  • the fifth access network device sends a data packet carrying only the first sequence number to the terminal device.
  • the fifth access network device sends the data packet to the terminal device in the order of data received from the core network device. For example, if the core network device sends the data packet to the fifth access network device in order of the first sequence number from small to large, the fifth access network device sends the data packet to the terminal device in order of the first sequence number from small to large.
  • the terminal device After receiving the data packet from the fifth access network device, the terminal device will send a feedback of receiving the data packet to the fifth access network device to indicate whether the data packet is successfully received.
  • the terminal device will send a feedback of receiving the data packet to the fifth access network device to indicate whether the data packet is successfully received.
  • each time the terminal device successfully receives a data packet the terminal device replies to the fifth access network device with an indication indicating confirmation of reception (e.g., an acknowledgement character (ACK)).
  • the indication indicating confirmation of reception indicates that the terminal device has received the data packet of the first sequence number.
  • the fifth access network device receives 5 data packets from the core network device, and the first sequence numbers of the 5 data packets are 1, 2, 3, 4, and 5 respectively. Then the fifth access network device first sends the data packet with sequence number 1, and then sends the data packet with sequence number 2, and so on. After receiving the data packet with sequence number 1, the terminal device will reply an ACK with sequence number 1 to the fifth access network device. After receiving the data packet with sequence number 2, the terminal device will reply an ACK with sequence number 2 to the fifth access network device, and so on.
  • the terminal device receives a feedback report indication from the fifth access network device, and the feedback report indication may be included in a data packet. If the terminal device receives the data packet including the feedback report indication and all previous data packets, the terminal device feeds back an ACK to the fifth access network device; if the terminal device receives the data packet including the feedback report indication, but the data before the data packet including the feedback report indication is not completely received, the terminal device feeds back the sequence number of the data packet that was not successfully received to the fifth access network device.
  • the fifth access network device receives 5 data packets from the core network device, and the first sequence numbers of the 5 data packets are 1, 2, 3, 4 and 5 respectively, and the data packet with the first sequence number of 5 contains a feedback report indication. If the terminal device receives the aforementioned 5 data packets, the terminal device feeds back ACK to the fifth access network device; if the terminal device only receives the data packet containing the feedback report indication (i.e., the data packet with the first sequence number of 5), but the data before the data packet containing the feedback report indication is not completely received (for example, only the data packets with the first sequence numbers of 1, 2, and 3 are received), the terminal device feeds back the sequence number of the data packet that was not successfully received (i.e., the first sequence number of 4) to the fifth access network device.
  • the terminal device feeds back ACK to the fifth access network device.
  • the fifth access network device may also determine whether the data packet received from the core network device is correctly received by the terminal device based on the correct reception status of the data packet at the RLC layer fed back by the terminal device at the RLC layer.
  • the fifth access network device determines the second sequence number of each data packet based on the first sequence number of each data packet and the first mapping rule, and then the fifth access network device sends the data packet carrying the second sequence number to the terminal device.
  • the sent data packet may carry the first sequence number in addition to the second sequence number.
  • the second sequence number is a PDCP SN.
  • the fifth access network device receives 5 data packets from the core network device, and the first sequence numbers of the 5 data packets are 1, 2, 3, 4 and 5 respectively. Then the fifth access network device first determines the second sequence number of each data packet based on the first sequence number of each data packet and the first mapping rule. For example, the second sequence number determined by the first sequence number 1 based on the first mapping rule is A, and the second sequence number determined by the first sequence number 2 based on the first mapping rule is B. By analogy, the fifth access network device can determine that the second sequence numbers of the 5 data packets are A, B, C, D and E respectively. Then, the fifth access network device first sends the data packet with sequence number A to the terminal device, and then sends the data packet with sequence number B, and so on.
  • the terminal device after receiving the data packet from the fifth access network device, the terminal device will send a feedback of receiving the data packet to the fifth access network device to indicate whether the data packet is successfully received. Specifically, it is similar to the feedback method in the above implementation manner and will not be repeated here.
  • the fifth access network device may also determine whether the data packet received from the core network device is correctly received by the terminal device based on the correct reception status of the data packet at the RLC layer fed back by the terminal device at the RLC layer.
  • At least one access network device determined by the core network device has the same first mapping rule.
  • Step 804 The fifth access network device sends sixth indication information to the terminal device.
  • the terminal device receives sixth indication information from the fifth access network device.
  • Step 804 is an optional step.
  • the fifth access network device Before the fifth access network device stops providing services to the terminal device, if the fifth access network device still has data packets that need to be sent to the terminal device, or there are data packets that have been sent but have not received ACK, the fifth access network device sends the sixth indication information to the terminal device, and the sixth indication information is used to indicate that there are data packets to be sent.
  • the data packets to be sent can be data packets that have not been successfully sent, that is, data packets that the fifth access network device has sent but has not received ACK; or they can be unsent data packets, that is, data packets that have never been sent by the fifth access network device.
  • the sixth indication information may be in the form of MAC CE, or in the form of MAC PDU (for example, the sixth indication information is carried in the PDCP layer or the RLC layer), and the specific indication form is not limited.
  • the sixth indication information is the first quantity information
  • the first quantity information is the total number of data packets of the terminal device received by the fifth access network device from the core network device.
  • the terminal device determines whether there are any unreceived data packets based on the number of received data packets and the first quantity information. For example, if the fifth access network device receives 5 data packets from the core network device, the first quantity information is 5. If the terminal device has received 3 data packets, the terminal device can determine that there are still data packets to be received.
  • the sixth indication information is second quantity information
  • the second quantity information is the number of data packets to be sent in the fifth access network device. If the value of the second quantity information is 0, it indicates that there are no data packets to be sent in the fifth access network device; if the value of the second quantity information is non-0, it indicates that there are data packets to be sent in the fifth access network device.
  • step 804 is an optional step. If the fifth access network device does not execute step 804, when the fifth access network device stops providing services to the terminal device, the terminal device does not receive an instruction to release or suspend the connection from the fifth access network device, then the terminal device determines that there are still data packets to be sent in the fifth access network device.
  • step 804 is an optional step. If the fifth access network device does not execute step 804, when the fifth access network device stops serving the terminal, the terminal device connects to the sixth access network device (step 807), and the terminal device decides whether to send step 808 to the sixth access network device.
  • Step 805 The core network device sends the context of the terminal device and multiple data packets of the terminal device to the sixth access network device, each data packet corresponding to a first sequence number.
  • At least one access network device further includes a sixth access network device
  • the sixth access network device is an access network device that provides services to the terminal device after the fifth access network device stops providing services to the terminal device, that is, the fifth access network device arrives at the geographical area where the terminal device is located earlier than the sixth access network device.
  • the fifth access network device is the first access network device among the at least one access network device to arrive at the geographical area where the terminal device is located
  • the sixth access network device is the second access network device among the at least one access network device to arrive at the geographical area where the terminal device is located.
  • the access network device Since the access network device has the characteristic of mobility (for example, the fifth access network device can move on the running track), the time for a single access network device to serve the terminal device is limited. Therefore, a single access network device may not be able to transmit all the data that needs to be sent to the terminal device. Therefore, in addition to sending multiple data packets to the fifth access network device, the core network device also sends the context of the terminal device and multiple data packets of the terminal device to the sixth access network device, each data packet corresponding to a first sequence number, so that the sixth access network device continues to send data to the terminal device. Send downlink data packets.
  • the core network device also sends the context of the terminal device and multiple data packets of the terminal device to the sixth access network device, each data packet corresponding to a first sequence number, so that the sixth access network device continues to send data to the terminal device. Send downlink data packets.
  • step 805 may be performed simultaneously with step 801 , or may be performed after step 801 and before step 806 , which is not limited here.
  • Step 806 The sixth access network device moves to the geographical area where the terminal device is located.
  • Step 807 The terminal device establishes a connection with the sixth access network device.
  • the sixth access network device establishes a connection with the terminal device based on the context of the terminal device.
  • the process of establishing a connection between the terminal device and the sixth access network device can be implemented in accordance with the method provided in the corresponding embodiment of Figure 3 (for example, step 311) or the corresponding embodiment of Figure 5 (for example, step 511) of the previous text, or other methods can be used to establish the connection between the terminal device and the sixth access network device.
  • This embodiment does not limit the method for establishing a connection between the terminal device and the sixth access network device.
  • Step 808 The terminal device sends seventh indication information to the sixth access network device.
  • the sixth access network device receives the seventh indication information from the terminal device.
  • the seventh indication information is used to indicate the data packets that have been successfully received by the terminal device in succession and/or the next data packet to be received by the terminal device.
  • the seventh indication information includes a target sequence number.
  • the target sequence number is the sequence number of the last data packet that the terminal device has continuously confirmed to receive. For example, if the terminal device has received a data packet with a sequence number of 1, a data packet with a sequence number of 2, a data packet with a sequence number of 3, and a data packet with a sequence number of 5, the target sequence number is 3, which is used to instruct the sixth access network device to send data packets starting from sequence number 4.
  • the target sequence number includes the sequence number of the first data packet after the terminal device has continuously confirmed the receipt of the data packet. For example, if the terminal device has received a data packet with a sequence number of 1, a data packet with a sequence number of 2, a data packet with a sequence number of 3, and a data packet with a sequence number of 5, the sequence number included in the seventh indication information is 4, which is used to instruct the sixth access network device to send data packets starting from sequence number 4.
  • the target sequence number includes the sequence number of the last received data packet and the sequence numbers of the data packets that have not been ACKed before the last received data packet. For example, if the terminal device has received a data packet with a sequence number of 1, a data packet with a sequence number of 2, a data packet with a sequence number of 3, and a data packet with a sequence number of 5, the seventh indication information will feedback sequence number 5 and sequence number 4, indicating that the sequence number of the last received data packet is 5, and the sequence number of the unreceived data packet is 4.
  • the target sequence number includes the sequence number of a data packet after the last received data packet and the sequence number of the data packet that has not been ACKed before the last received data packet. For example, if the terminal device has received a data packet with sequence number 1, a data packet with sequence number 2, a data packet with sequence number 3, and a data packet with sequence number 5, the seventh indication information will feedback sequence number 6 and sequence number 4, indicating that the sequence number of the latest data packet to be sent is 6, the sequence number of the data packet that has not been received among the sent data packets is 4, and the data packet with sequence number 4 can be resent.
  • the target sequence number includes an indication of which data packets are correctly received or which data packets are not correctly received. For example, if the terminal device has received a data packet with a sequence number of 1, a data packet with a sequence number of 2, a data packet with a sequence number of 3, and a data packet with a sequence number of 5, the seventh indication information then feeds back that the data packets with sequence numbers of 1, 2, 3, and 5 have been correctly received by the terminal device.
  • any one of the aforementioned implementations may be used to implement the seventh indication information.
  • the serial number in the seventh indication information refers to the first serial number; if the sixth access network device sends a second serial number to the terminal device, the serial number indicated in the seventh indication information is the second serial number.
  • Step 809 The sixth access network device sends a data packet to the terminal device according to the seventh indication information.
  • the terminal device receives a data packet from the sixth access network device.
  • the sixth access network device sends a data packet to the terminal device based on the seventh indication information.
  • the sixth access network device compares the data packet received by the sixth access network device from the core network device based on the sequence number indicated by the received seventh indication information. If the sixth access network device determines that the terminal device has received all the data packets sent by the core network device, the sixth access network device does not send the data packet to the terminal device; if the terminal device has not received all the data packets sent by the core network device, the sixth access network sends the data packet to the terminal device according to the seventh indication information.
  • the target sequence number can be the first sequence number or the second sequence number. They are introduced below respectively:
  • the target sequence number is the first sequence number.
  • the sixth access network device sends at least one data packet carrying the first sequence number to the terminal device, and the first sequence number of each data packet in the at least one data packet is greater than or equal to the target sequence number.
  • the target sequence number is the second sequence number.
  • the sixth access network device determines the second sequence number of each data packet based on the first sequence number of each data packet and the first mapping rule; the sixth access network device sends at least one data packet carrying the second sequence number to the terminal device, and the second sequence number of each data packet in the at least one data packet is greater than or equal to the target sequence number.
  • the target sequence number is taken as the sequence number of the last data packet that the terminal device has continuously confirmed to receive.
  • the terminal device has received a data packet with a sequence number of A, a data packet with a sequence number of B, and a data packet with a sequence number of C, and the target sequence number is C.
  • the sixth access network device determines that the second sequence number of the data packet is D based on the data packet with a sequence number of 4, and determines that the second sequence number of the data packet is E based on the data packet with a sequence number of 5. Then, the sixth access network device continues to send data packets with a sequence number of D and a data packet with a sequence number of E to the terminal device, and so on.
  • the core network device can copy multiple data packets of the terminal device and send the data packets of the terminal device to multiple access network devices, and send the context of the terminal device to multiple access network devices, when one of the access network devices cannot send all the data packets to the terminal device, the data packets can be sent to the terminal device through other access network devices. This is conducive to maintaining the continuity of the data received by the terminal device.
  • the embodiment of the present application also provides a corresponding communication device (sometimes also referred to as a communication device) and a communication system, wherein the communication device includes a module or unit for executing each part of the foregoing embodiment.
  • the module or unit may be software, hardware, or a combination of software and hardware. The following only briefly describes the communication device and system. For the implementation details of the scheme, reference may be made to the description of the foregoing method embodiment, which will not be repeated below.
  • FIG 9 it is a schematic diagram of the structure of a communication device 90 provided in this embodiment. It should be understood that the terminal device in the method embodiment corresponding to Figures 2, 3, 5, 7 or 8 can be based on the structure of the communication device 90 shown in Figure 9 in this embodiment.
  • the communication device 90 includes at least one processor 901, at least one memory 902, and at least one transceiver 903.
  • the processor 901, the memory 902, and the transceiver 903 are connected.
  • the communication device 90 may also include an input device 905, an output device 906, and one or more antennas 904.
  • the antenna 904 is connected to the transceiver 903, and the input device 905 and the output device 906 are connected to the processor 901.
  • the memory 902 is mainly used to store software programs and data.
  • the memory 902 can be independent and connected to the processor 901.
  • the memory 902 can be integrated with the processor 901, for example, integrated into one or more chips.
  • the memory 902 can store the program code for executing the technical solution of the embodiment of the present application, and the execution is controlled by the processor 901, and the various types of computer program codes executed can also be regarded as the driver of the processor 901.
  • Figure 9 in this embodiment only shows a memory and a processor, but in practical applications, the communication device 90 can have multiple processors or multiple memories, which is not limited here.
  • the memory 902 can also be referred to as a storage medium or a storage device.
  • the memory 902 can be a storage element (i.e., an on-chip storage element) on the same chip as the processor, or an independent storage element, which is not limited in the embodiment of the present application.
  • the transceiver 903 can be used to support the reception or transmission of radio frequency signals between the communication device 90 and the access network device, and the transceiver 903 can be connected to the antenna 904.
  • the transceiver 903 includes a transmitter Tx and a receiver Rx.
  • one or more antennas 904 can receive radio frequency signals
  • the receiver Rx of the transceiver 903 is used to receive the radio frequency signals from the antenna 904, and convert the radio frequency signals into digital baseband signals or digital intermediate frequency signals, and provide the digital baseband signals or digital intermediate frequency signals to the processor 901, so that the processor 901 further processes the digital baseband signals or digital intermediate frequency signals, such as demodulation processing and decoding processing.
  • the transmitter Tx in the transceiver 903 is also used to receive the modulated digital baseband signals or digital intermediate frequency signals from the processor 901, and convert the modulated digital baseband signals or digital intermediate frequency signals into radio frequency signals, and send the radio frequency signals through one or more antennas 904.
  • the receiver Rx can selectively perform one or more stages of down-mixing and analog-to-digital conversion processing on the RF signal to obtain a digital baseband signal or a digital intermediate frequency signal, and the order of the down-mixing and analog-to-digital conversion processing is adjustable.
  • the transmitter Tx can selectively perform one or more stages of up-mixing and digital-to-analog conversion processing on the modulated digital baseband signal or digital intermediate frequency signal to obtain a RF signal, and the order of the up-mixing and digital-to-analog conversion processing is adjustable.
  • the digital baseband signal and the digital intermediate frequency signal can be collectively referred to as a digital signal.
  • the transceiver 903 may also be referred to as a transceiver unit, a transceiver, a transceiver device, etc.
  • a device for implementing a receiving function in a transceiver unit may be regarded as a receiving unit
  • a device for implementing a sending function in a transceiver unit may be regarded as a sending unit. That is, the transceiver unit includes a receiving unit and a sending unit.
  • the receiving unit can also be called a receiver, an input port, a receiving circuit, etc.
  • the sending unit can be called a transmitter, a transmitter or a transmitting circuit, etc.
  • Processor 901 may be a baseband processor or a central processing unit (CPU), and the baseband processor and the CPU may be integrated or separated. Processor 901 may be used to implement various functions for the terminal device, such as processing communication protocols and communication data, or controlling the entire terminal device, executing software programs, and processing data of software programs; or assisting in completing computing tasks, such as graphics and image processing or audio processing, etc.; or processor 901 is used to implement one or more of the above functions.
  • processor 901 is used to implement one or more of the above functions.
  • the output device 906 communicates with the processor 901 and can display information in a variety of ways, which are not specifically limited herein.
  • the communication device 90 is used to execute the method of the terminal device in the embodiment corresponding to Figure 2, Figure 3 or Figure 5.
  • the transceiver 903 in the communication device 90 is used to receive the first indication information from the first access network device, and the first indication information is used to indicate that the first access network device cannot interact with the core network device; after the terminal device accesses the first access network device, the processor 901 controls the memory 902 to store the context of the terminal device according to the first indication information, and the context of the terminal device is the information used by the terminal device to access the second access network device after the first access network device stops providing services for the terminal device.
  • the second access network device is an access network device having the context of the terminal device.
  • the processor 901 is further configured to establish a connection with the second access network device based on the context of the terminal device after the first access network device stops providing services for the terminal device.
  • the second access network device and the first access network device are the same access network device.
  • the processor 901 is specifically configured to access a first cell of the first access network device based on the context of the terminal device, where the first cell is a cell stored in the context of the terminal device.
  • the context of the terminal device includes the cell identification information of the first cell.
  • the transceiver 903 is configured to receive the cell identification information of the first cell from the first access network device; the processor 901 is configured to access the first cell based on the cell identification information of the first cell.
  • the transceiver 903 is further used to receive second indication information from the first access network device, where the second indication information is used to instruct the terminal device to initiate access; the processor 901 is further used to access the first cell of the first access network device based on the second indication information.
  • the second access network device and the first access network device are different access network devices; the context of the terminal device includes the cell identification information of the first cell.
  • the transceiver 903 is used to receive the cell identification information of the first cell from the second access network device; the processor 901 is used to access the second cell of the second access network device based on the cell identification information of the first cell.
  • the second access network device and the first access network device are different access network devices.
  • the transceiver 903 receives third indication information from the second access network device, and the third indication information is used to instruct the terminal device to initiate access; the processor 901 accesses the second cell of the second access network device based on the third indication information.
  • the transceiver 903 receives first identification information from the first access network device, where the first identification information is used to uniquely identify the terminal device for the first access network device.
  • the transceiver 903 sends an uplink NAS message of the terminal device to the first access network device; sends first identification information to the second access network device, where the first identification information is used by the second access network device to determine the context of the terminal device; and receives a downlink NAS message of the terminal device from the second access network device.
  • the processor 901 is specifically used to: start a first NAS timer when sending an uplink NAS message, where the first NAS timer is a NAS timer used when the access network device cannot interact with the core network device; or, start a second NAS timer after a first period of time after sending the uplink NAS message, where the second NAS timer is a NAS timer used when the access network device can interact with the core network device.
  • the transceiver 903 is further configured to receive first time information from the first access network device, where the first time information is used to determine a duration of the first NAS timer or a first duration.
  • the communication device 90 is used to execute the method of the terminal device in the embodiment corresponding to Figure 7.
  • the transceiver 903 in the communication device 90 is used to receive a paging message from a third access network device.
  • the transceiver 903 in the communication device 90 is used to receive a paging message from a fourth access network device.
  • the communication device 90 is used to execute the method of the terminal device in the embodiment corresponding to Figure 8 above.
  • the transceiver 903 in the communication device 90 is used to receive a data packet carrying the first sequence number or the second sequence number from the fifth access network device, and to send an indication indicating confirmation of reception of the received data packet to the fifth access network device (for example, an acknowledgement character (ACK)).
  • the transceiver 903 will also send seventh indication information to the sixth access network device, and the seventh indication information is used to indicate the data packets that the terminal device has successfully received continuously.
  • the seventh indication information includes a target sequence number, which is the sequence number of the last data packet that the terminal device has continuously confirmed to receive.
  • FIG10 it is a schematic diagram of the structure of another communication device 100 provided in this embodiment.
  • the access network device in the method embodiment corresponding to the aforementioned FIG2, FIG3, FIG5, FIG7 or FIG8 can be based on the structure of the communication device 100 shown in FIG10 in this embodiment.
  • the communication device 100 includes at least one processor 1001, at least one memory 1002, at least one transceiver 1003, at least one network interface 1005, and one or more antennas 1004.
  • the processor 1001, the memory 1002, the transceiver 1003, and the network interface 1005 are connected via a connecting device, and the antenna 1004 is connected to the transceiver 1003.
  • the aforementioned connecting device may include various interfaces, transmission lines, or buses, etc., which are not limited in this embodiment.
  • the memory 1002 is mainly used to store software programs and data.
  • the memory 1002 can be independent and connected to the processor 1001.
  • the memory 1002 can be integrated with the processor 1001, for example, integrated into one or more chips.
  • the memory 1002 can store the program code for executing the technical solution of the embodiment of the present application, and the execution is controlled by the processor 1001, and the various types of computer program codes executed can also be regarded as the driver of the processor 1001.
  • Figure 10 in this embodiment only shows a memory and a processor, but in actual applications, the communication device 100 can have multiple processors or multiple memories, which is not limited here.
  • the memory 1002 can also be referred to as a storage medium or a storage device.
  • the memory 1002 can be a storage element (i.e., an on-chip storage element) on the same chip as the processor, or an independent storage element, which is not limited in the embodiment of the present application.
  • the transceiver 1003 can be used to support the reception or transmission of radio frequency signals between the communication device 100 and the terminal device, and the transceiver 1003 can be connected to the antenna 1004.
  • the transceiver 1003 includes a transmitter Tx and a receiver Rx.
  • one or more antennas 1004 can receive radio frequency signals
  • the receiver Rx of the transceiver 1003 is used to receive the radio frequency signal from the antenna 1004, and convert the radio frequency signal into a digital baseband signal or a digital intermediate frequency signal, and provide the digital baseband signal or the digital intermediate frequency signal to the processor 1001, so that the processor 1001 further processes the digital baseband signal or the digital intermediate frequency signal, such as demodulation processing and decoding processing.
  • the transmitter Tx in the transceiver 1003 is also used to receive a modulated digital baseband signal or a digital intermediate frequency signal from the processor 1001, and convert the modulated digital baseband signal or the digital intermediate frequency signal into a radio frequency signal, and send the radio frequency signal through one or more antennas 1004.
  • the receiver Rx can selectively perform one or more stages of down-mixing and analog-to-digital conversion processing on the RF signal to obtain a digital baseband signal or a digital intermediate frequency signal, and the order of the down-mixing and analog-to-digital conversion processing is adjustable.
  • the transmitter Tx can selectively perform one or more stages of up-mixing and digital-to-analog conversion processing on the modulated digital baseband signal or digital intermediate frequency signal to obtain a RF signal, and the order of the up-mixing and digital-to-analog conversion processing is adjustable.
  • the digital baseband signal and the digital intermediate frequency signal can be collectively referred to as a digital signal.
  • the aforementioned transceiver 1003 may also be referred to as a transceiver unit, a transceiver, a transceiver device, etc.
  • a device in the transceiver unit for implementing a receiving function may be regarded as a receiving unit
  • a device in the transceiver unit for implementing a sending function may be regarded as a sending unit, that is, the transceiver unit includes a receiving unit and a sending unit
  • the receiving unit may also be referred to as a receiver, an input port, a receiving circuit, etc.
  • the sending unit may be referred to as a transmitter, a transmitter, or a transmitting circuit, etc.
  • the aforementioned processor 1001 is mainly used to process the communication protocol and communication data, and to control the entire network device, execute the software program, and process the data of the software program, for example, to support the communication device 100 to perform the actions described in the aforementioned embodiments.
  • the communication device 100 may include a baseband processor and a central processing unit, wherein the baseband processor is mainly used to process the communication protocol and communication data, and the central processing unit is mainly used to control the entire communication device 100, execute the software program, and process the data of the software program.
  • the processor 1001 can integrate the functions of the baseband processor and the central processing unit.
  • the baseband processor 100 and the central processing unit may also be independent processors, interconnected by technologies such as buses.
  • the communication device 100 may include multiple baseband processors to adapt to different network formats, the communication device 100 may include multiple central processing units to enhance its processing capabilities, and the various components of the communication device 100 may be connected via various buses.
  • the baseband processor may also be described as a baseband processing circuit or a baseband processing chip.
  • the central processing unit may also be described as a central processing circuit or a central processing chip.
  • the function of processing the communication protocol and communication data may be built into the processor, or may be stored in the memory in the form of a software program, and the processor executes the software program to implement the baseband processing function.
  • the aforementioned network interface 1005 is used to connect the communication device 100 to other communication devices through a communication link.
  • the network interface 1005 may include a network interface between the communication device 100 and a core network element, such as an S1 interface; the network interface 1005 may also include a network interface between the communication device 100 and other network devices (such as other access network devices or core network elements), such as an X2 or Xn interface.
  • the communication device 100 is used to execute the method of the first access network device in the embodiment corresponding to the aforementioned FIG. 2, FIG. 3 or FIG. 5.
  • the transceiver 1003 in the communication device 100 is used to broadcast the first indication information, and the first indication information is used to indicate that the first access network device cannot exchange information with the core network device;
  • the processor 1001 is used to establish a connection with the terminal device;
  • the memory 1002 is used to store the context of the terminal device after the first access network device establishes a connection with the terminal device, and the context of the terminal device is the information that the second access network device accepts the use of the terminal device after the first access network device stops providing services for the terminal device.
  • the transceiver 1003 is used to broadcast the first indication information in a first area, where the first area is an area where the access network device cannot establish a connection with the core network device.
  • the transceiver 1003 is used to receive an uplink NAS message from a terminal device in a first area; the processor 1001 is also used to control the transceiver 1003 to send an uplink NAS message to the core network device when the first access network device moves to a second area, and the second area is an area where the access network device can establish a connection with the core network device.
  • the second access network device is the first access network device.
  • the processor 1001 establishes a connection with the terminal device based on the context of the terminal device.
  • the processor 1001 is used to provide services for the terminal device through a first cell of a first access network device based on the context of the terminal device, where the first cell is a cell accessed by the terminal device when the first access network device stores the context of the terminal device.
  • the transceiver 1003 is used to broadcast the cell identification information of the first cell in the first area, and the cell identification information of the first cell is used for the terminal device to access the first cell.
  • the transceiver 1003 is used to send second indication information to the terminal device in the first cell, where the second indication information is used to instruct the terminal device to initiate access based on the context of the terminal device.
  • the transceiver 1003 is configured to receive a downlink NAS message of the terminal device from the core network device in the second area; and send a downlink NAS message to the terminal device.
  • the transceiver 1003 is configured to send first identification information to the terminal device, the first identification information being used to uniquely identify the terminal device for the first access network device; and, receive the first identification information from the terminal device.
  • the processor 1001 is configured to determine a context of the terminal device based on the first identification information of the terminal device; and, determine a downlink NAS message based on the context of the terminal device.
  • the context of the terminal device includes geographic area information of the terminal device; the processor 1001 is used to determine the context of the terminal device based on the cell wireless network temporary identifier of the terminal device and the geographic area information of the terminal device; and, determine a downlink NAS message based on the context of the terminal device.
  • the context of the terminal device includes time information when the terminal device accesses the first access network device.
  • the processor 1001 is configured to determine the context of the terminal device based on the cell radio network temporary identifier of the terminal device and the time information when the terminal device accesses the first access network device; and determine a downlink NAS message based on the context of the terminal device.
  • the second access network device and the first access network device are different access network devices.
  • the processor 1001 is used to control the transceiver 1003 to send the context of the terminal device to the core network device when the first access network device moves to the second area, the second area is an area where the access network device can establish a connection with the core network device, and the context of the terminal device is used for the second access network device determined by the core network device to establish a connection with the terminal device.
  • the transceiver 1003 is configured to broadcast first time information in a first area, where the first time information is used to determine a first NAS timer.
  • the processor 1001 is used to control the transceiver 1003 to send fourth indication information to the core network device when the first access network device moves to the second area, and the fourth indication information is used to instruct the terminal device to access the first access network device when the first access network device cannot establish a connection with the core network device.
  • the processor 1001 is used to control the transceiver 1003 to send first time information to the core network device when the first access network device moves to the second area, and the first time information is used to determine a first NAS timer of the core network device.
  • the communication device 100 is used to execute the method of the second access network device in the embodiment corresponding to Figure 2, Figure 3 or Figure 5.
  • the transceiver 1003 is used to receive the context of the terminal device and the downlink NAS message of the terminal device from the core network device; the processor 1001 is used to determine the geographical area where the terminal device is located based on the context of the terminal device; the processor 1001 is also used to control the transceiver 1003 to send second indication information to the terminal device when the second access network device moves to the geographical area where the terminal device is located, and the second indication information is used to instruct the terminal device to initiate random access; and after the terminal device accesses, control the transceiver 1003 to send the downlink NAS message of the terminal device to the terminal device.
  • the transceiver 1003 is configured to receive first identification information from a terminal device, where the first identification information is used to uniquely identify the terminal device for the first access network device.
  • the processor 1001 is configured to determine a context of the terminal device based on the first identification information; and determine a downlink NAS message based on the context of the terminal device.
  • the context of the terminal device includes the geographical area information of the terminal device.
  • the processor 1001 is configured to determine the context of the terminal device based on the cell radio network temporary identifier of the terminal device and the geographical area information of the terminal device; and determine a downlink NAS message based on the context of the terminal device.
  • the context of the terminal device includes time information when the terminal device accesses the first access network device.
  • the processor 1001 determines the context of the terminal device based on the cell radio network temporary identifier of the terminal device and the time information when the terminal device accesses the first access network device; and determines a downlink NAS message based on the context of the terminal device.
  • the communication device 100 is used to execute the method of the third access network device in the embodiment corresponding to Fig. 7.
  • the transceiver 1003 in the communication device 100 is used to receive a paging message, and the paging message includes the geographical area information of the terminal device; the processor 1001 is used to control the transceiver 1003 to broadcast the paging message in the geographical area where the terminal device is located when the third access network device moves to the geographical area where the terminal device is located.
  • the transceiver 1003 is used to send a fifth indication message to a fourth access network device, where the fourth access network device is an access network device that provides services to the terminal device after the third access network device stops providing services to the terminal device, and the fifth indication information is used to instruct the fourth access network device to delete a paging message used to paging the terminal device.
  • the communication device 100 is used to execute the method of the fourth access network device in the embodiment corresponding to Figure 7.
  • the transceiver 1003 is used to receive fifth indication information from the third access network device, and the fifth indication information is used to instruct the fourth access network device to delete the paging message used to paging the terminal device.
  • the communication device 100 is used to execute the method of the fifth access network device in the embodiment corresponding to the aforementioned FIG8.
  • the transceiver 1003 in the communication device 100 is used to receive multiple data packets of the terminal device from the core network device, each data packet corresponding to a first sequence number; the processor 1001 is used to control the transceiver 1003 to send a data packet carrying the first sequence number to the terminal device based on the first sequence number when the fifth access network device moves to the geographical area where the terminal device is located; or, when the fifth access network device moves to the geographical area where the terminal device is located, determine the second sequence number of each data packet based on the first sequence number of each data packet and the first mapping rule, and control the transceiver 1003 to send a data packet carrying the second sequence number to the terminal device based on the second sequence number.
  • the processor 1001 is configured to control the transceiver 1003 to send sixth indication information to the terminal device before stopping providing services for the terminal device, where the sixth indication information is used to indicate that there is a data packet to be sent.
  • the communication device 100 is used to execute the method of the sixth access network device in the embodiment corresponding to the aforementioned FIG8.
  • the transceiver 1003 is used to receive multiple data packets of the terminal device and the context of the terminal device from the core network device, each data packet corresponding to a first sequence number; the processor 1001 is used to establish a connection with the terminal device based on the context of the terminal device; the transceiver 1003 receives seventh indication information from the terminal device, the seventh indication information is used to indicate the data packets that the terminal device has successfully received continuously; and, based on the seventh indication information, at least one data packet of the multiple data packets is sent to the terminal device.
  • the seventh indication information includes a target sequence number, where the target sequence number is the sequence number of the last data packet that the terminal device has continuously confirmed to have received.
  • the target sequence number is the first sequence number.
  • the transceiver 1003 is configured to send at least one data packet carrying the first sequence number to the terminal device, wherein the first sequence number of each data packet in the at least one data packet is greater than the target sequence number.
  • the target sequence number is the second sequence number.
  • the processor 1001 is used to determine the second sequence number of each data packet based on the first sequence number of each data packet and the first mapping rule; the transceiver 1003 is used to send at least one data packet carrying the second sequence number to the terminal device, and the second sequence number of each data packet in the at least one data packet is greater than the target sequence number.
  • FIG11 it is a schematic diagram of the structure of another communication device 110 provided in this embodiment.
  • the core network device in the method embodiment corresponding to the aforementioned FIG2, FIG3, FIG5, FIG7 or FIG8 can be based on the structure of the communication device 110 shown in FIG11 in this embodiment.
  • the communication device 110 may include a processor 1101, a memory 1103 and a communication interface 1102. Among them, the processor 1101 is coupled to the memory 1103, and the processor 1101 is coupled to the communication interface 1102.
  • the communication interface 1102 is connected to other communication devices via a communication link.
  • the communication interface 1102 may include a network interface between the communication device 100 and an access network device (eg, the communication device 90 shown in FIG. 9 ), such as an S1 interface.
  • the processor 1101 may be a central processing unit (CPU), an application-specific integrated circuit (ASIC), a programmable logic device (PLD) or a combination thereof.
  • the PLD may be a complex programmable logic device (CPLD), a field-programmable gate array (FPGA), a generic array logic (GAL) or any combination thereof.
  • the processor 1101 may refer to one processor or may include multiple processors, which is not specifically limited here.
  • the aforementioned memory 1103 is mainly used to store software programs and data.
  • the memory 1103 may exist independently and be connected to the processor 1101.
  • the memory 1103 may be integrated with the processor 1101, for example, integrated into one or more chips.
  • the memory 1103 can store program codes for executing the technical solutions of the embodiments of the present application, and is controlled and executed by the processor 1101, and the various types of computer program codes executed can also be regarded as drivers of the processor 1101.
  • the memory 1103 may include volatile memory (volatile memory), such as random-access memory (random-access memory, RAM); the memory may also include non-volatile memory (non-volatile memory), such as read-only memory (read-only memory, ROM), flash memory (flash memory), hard disk (hard disk drive, HDD) or solid-state drive (solid-state drive, SSD); the memory 1103 may also include a combination of the above-mentioned types of memory.
  • the memory 1103 may refer to one memory or may include multiple memories. Exemplarily, the memory 1103 is used to store various data. For example, the first reference position, the first distance threshold. In addition, the memory 1103 is also used to store the first rule information, the second rule information, the third rule information, and the fourth rule information. Specifically, please refer to the relevant introduction in the above embodiment, which will not be repeated here.
  • the communication device 110 is used to execute the method of the core network device in the embodiment corresponding to Figure 2, Figure 3 or Figure 5.
  • the communication interface 1102 is used to receive an uplink NAS message and fourth indication information of a terminal device from a first access network device, and the fourth indication information is used to indicate that the terminal device accesses the first access network device when the first access network device cannot interact with the core network device; the processor 1101 is used to activate the first NAS timer based on the fourth indication information.
  • the communication interface 1102 is used to receive first time information from the first access network device, where the first time information is used to determine a first NAS timer of the core network device.
  • the communication interface 1102 is used to send a downlink NAS message of the terminal device to the first access network device, and the core network device starts the first NAS timer; before the first NAS timer times out, the processor 1101 receives an uplink NAS message corresponding to the downlink NAS message from the first access network device through the communication interface 1102.
  • the processor 1101 sends a downlink NAS message of the terminal device to the second access network device through the communication interface 1102 before the first NAS timer times out, and the core network device starts the first NAS timer, and the second access network device is an access network device that moves to the geographical area where the terminal device is located; the processor 1101 receives an uplink NAS message corresponding to the downlink NAS message through the communication interface 1102 before the first NAS timer times out.
  • the communication interface 1102 is used to receive the context of the terminal device from the first access network device; the processor 1101 is used to determine the second access network device based on the context of the terminal device; the communication interface 1101 is also used to send the second access network device to the second access network device.
  • the network device sends the context of the terminal device.
  • the communication device 110 is used to execute the method of the core network device in the embodiment corresponding to the aforementioned FIG7.
  • the processor 1101 is used to determine at least one access network device according to the geographical area information of the terminal device, the current coverage area of the access network device does not include the geographical area where the terminal device is located, and the mobile path of the coverage area of the access network device passes through the geographical area where the terminal device is located;
  • the communication interface 1102 is used to send a paging message to the at least one access network device, and the paging message includes the geographical area information of the terminal device.
  • the communication interface 1102 is configured to, when sending the paging message, enable the core network device to start a first paging timer, and the duration of the first paging timer is greater than the duration of a preconfigured paging timer.
  • the communication device 110 is used to execute the method of the core network device in the embodiment corresponding to the aforementioned FIG8.
  • the processor 1101 is used to determine multiple data packets of the terminal device and the first sequence number corresponding to each data packet.
  • the communication interface 1102 is used to send multiple data packets of the terminal device, each of which corresponds to a first sequence number; the communication interface 1102 is also used to send the context of the terminal device and multiple data packets of the terminal device to the sixth access network device, and the sixth access network device is an access network device that provides services to the terminal device after the fifth access network device stops providing services to the terminal device.
  • the context of the terminal device is used for the sixth access network device to establish a connection with the terminal device and send multiple data packets of the terminal device to the terminal device.
  • the present application further provides a communication device 120.
  • the communication device 120 may be a terminal device, an access network device, or a core network device, or may be a component (e.g., an integrated circuit, a chip, etc.) of the terminal device, the access network device, or the core network device.
  • the communication device 120 may also be other communication modules for implementing the method in the method embodiment of the present application.
  • the communication device 120 may include a processing module 1201 (or a processing unit). Optionally, it may also include an interface module 1202 (or a transceiver unit or a transceiver module) and a storage module 1203 (or a storage unit). The interface module 1202 is used to communicate with other devices.
  • the interface module 1202 may be, for example, a transceiver module or an input/output module.
  • one or more modules in FIG. 12 may be implemented by one or more processors, or by one or more processors and memories; or by one or more processors and transceivers; or by one or more processors, memories, and transceivers, which are not limited in the embodiments of the present application.
  • the processor, memory, and transceiver may be provided separately or integrated into one.
  • the communication device 120 has the function of implementing the terminal device described in the embodiment of the present application.
  • the communication device 120 includes a module or unit or means (means) corresponding to the terminal device performing the steps involved in the terminal device described in the embodiment of the present application.
  • the function or unit or means (means) can be implemented by software, or by hardware, or by hardware executing the corresponding software implementation, or by a combination of software and hardware.
  • the communication device 120 has the function of implementing the access network device described in the embodiment of the present application.
  • the communication device 120 includes a module or unit or means (means) corresponding to the access network device executing the steps involved in the access network device described in the embodiment of the present application.
  • the function or unit or means (means) can be implemented by software, or by hardware, or by hardware executing the corresponding software implementation, or by a combination of software and hardware.
  • the communication device 120 has the functions of implementing the core network device described in the embodiment of the present application.
  • the communication device 120 includes a module or unit or means (means) corresponding to the core network device executing the steps involved in the core network device described in the embodiment of the present application.
  • the function or unit or means (means) can be implemented by software, or by hardware, or by hardware executing the corresponding software implementation, or by a combination of software and hardware.
  • the communication device 110 in the corresponding embodiment of Figure 11 above.
  • the present application provides a computer program product, which includes one or more computer instructions.
  • the process or function according to the embodiment of the present application is generated in whole or in part.
  • the method related to the access network device as shown in Figures 2, 3, 5, 7 or 8 is implemented.
  • the method related to the terminal device as shown in Figures 2, 3, 5, 7 or 8 is implemented.
  • the method related to the core network device as shown in Figures 2, 3, 5, 7 or 8 is implemented.
  • the computer may be a general-purpose computer, a special-purpose computer, a computer network or other programmable device.
  • the computer instructions may 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 may be transmitted from one website, computer, server or data center to another website, computer, server or data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means.
  • the computer-readable storage medium may be any available medium that a computer can store or a data storage device such as a server or data center that includes one or more available media integrated therein.
  • the available medium may be a magnetic medium (e.g., a floppy disk, a hard disk, a magnetic tape), an optical medium (e.g., a digital versatile disc (DVD)), or a semiconductor medium (e.g., a solid state disk (SSD)), etc.
  • the present application also provides a computer-readable storage medium, which stores a computer program, and the computer program is executed by a processor to implement a method related to an access network device as shown in the aforementioned Figures 2, 3, 5, 7 or 8.
  • the present application also provides a computer-readable storage medium, which stores a computer program, and the computer program is executed by a processor to implement a method related to the terminal device as shown in Figures 2, 3, 5, 7 or 8 above.
  • the present application also provides a computer-readable storage medium, which stores a computer program, and the computer program is executed by a processor to implement a method related to the core network device as shown in Figures 2, 3, 5, 7 or 8 above.
  • the size of the serial numbers of the above-mentioned processes does not mean the order of execution.
  • the execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Computer Security & Cryptography (AREA)
  • Business, Economics & Management (AREA)
  • Accounting & Taxation (AREA)
  • Physics & Mathematics (AREA)
  • Astronomy & Astrophysics (AREA)
  • General Physics & Mathematics (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

本申请公开了一种通信方法、通信装置及系统，在该方法中，终端设备接收来自第一接入网设备的第一指示信息，该第一指示信息用于指示所述第一接入网设备当前未与核心网设备连接；在终端设备接入所述第一接入网设备之后，终端设备根据第一指示信息存储终端设备的上下文，以使得在第一接入网设备停止为终端设备提供服务后能够基于终端设备的上下文接入第二接入网设备。上述方案能够提高终端设备接入接入网设备的效率，进而缩短终端设备与网络侧建立连接的时延。

Description

一种通信方法、通信装置及系统
本申请要求于2022年09月30日提交中国国家知识产权局、申请号为202211215589.8、申请名称为“一种通信方法、通信装置及系统”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领域，尤其涉及一种通信方法、通信装置及系统。
背景技术
在非陆地通信网络(non-terrestrial networks，NTN)的基于再生卫星(regenerative satellite)的无线接入网(radio access network，RAN)架构中，作为接入网设备的卫星不仅能够通过服务链路(service link)与地面终端设备交互信令，还能够通过馈电链路(feeder link)与地面的NTN网关连接，进而通过地面的NTN网关与核心网设备交互信令。
然而，在实际应用中，地面的NTN网关的部署可能受地形限制(例如，海面上无法布置NTN网关)，进而导致已部署NTN网关无法覆盖全部卫星。因此，可能存在部分为终端设备提供服务的卫星无法通过NTN网关与核心网设备建立连接，而导致终端设备无法通过接入网设备与核心网设备交互非接入层(non-access stratum，NAS)信令，进而导致终端设备可能在NAS定时器超时时触发尝试重新接入下一个接入网设备，以寻求网络服务。然而，终端设备在重新接入下一个接入网设备时一般需要重新配置与接入相关的信息，因此，可能导致终端设备耗费较长时间才接入下一个接入网设备，导致终端设备接入网络设备的效率较低，影响通信体验。
发明内容
本申请提供了一种通信方法、通信装置及系统，用于提高终端设备与接入网设备建立连接的效率，节省终端设备与第二接入网设备建连的信令开销。
第一方面，本申请提供了一种通信方法，该通信方法可以由终端设备执行，也可以由终端设备的部件(例如，处理器、芯片或芯片系统等部件)执行。以终端设备为例，终端设备接收来自第一接入网设备的第一指示信息，该第一指示信息用于指示该第一接入网设备不能与核心网设备交互信息；在该终端设备接入该第一接入网设备之后，该终端设备根据该第一指示信息存储该终端设备的上下文，该终端设备的上下文为该终端设备在该第一接入网设备停止为该终端设备提供服务后接入第二接入网设备使用的信息。
需要说明的是，第一指示信息仅指示该第一接入网设备当前没有与核心网设备建立连接，但是，该第一接入网设备具有与核心网设备建立连接的能力，该第一接入网设备在未来某一时刻可能与核心网设备建立连接。
示例性的，该第一指示信息可以是描述第一接入网设备的状态的标识信息，例如，无CN连接的标识。该第一指示信息也可以是描述数据传输模式的标识信息，例如，存储转发(store and forward)模式的标识。在实际应用中，还可以采用其他的标识信息或指示信息实现前述第一指示信息，本申请不限定第一指示信息的具体实现形式。
在一种可能的实施方式中，该第二接入网设备是具有该终端设备的上下文的接入网设备。
本申请中，终端设备能够基于来自第一接入网设备的第一指示信息确定该第一接入网设备未与核心网设备建立连接，并且，该终端设备基于第一指示信息在与第一接入网设备建立连接的过程中(或建立连接之后)存储终端设备的上下文。当该第一接入网设备停止为终端设备提供服务时，该终端设备的上下文中记载有终端设备接入第一接入网设备时使用的与接入相关的信息，该终端设备能够利用该终端设备的上下文中已有的与接入相关的信息接入到第二接入网设备，而不需要第二接入网设备重新进行RRC的初始建立，因此，有利于节省与第二接入网设备建连的信令开销，有利于提高终端设备接入第二接入网设备的效率，进而有利于缩短终端设备与网络侧建立连接的时延。
在一种可能的实施方式中，该终端设备根据该第一指示信息存储该终端设备的上下文之后，该方法还包括：在该第一接入网设备停止为该终端设备提供服务后，该终端设备基于该终端设备的上下文与该第二接入网设备建立连接。
在一类可能的实施方式中，该第二接入网设备与该第一接入网设备是同一接入网设备。例如，第一接入网设备在停止为终端设备提供服务的一段时长之后，该第一接入网设备再次移动到该终端设备所在的地理区域，进而该终端设备再次与第一接入网设备建立连接。此时，该终端设备基于该终端设备的上下文与该第二接入网设备进行连接，包括：该终端设备基于该终端设备的上下文接入该第一接入网设备的第一小区，该第一小区为该终端设备的上下文中存储的小区。
具体地，该终端设备可以基于如下任意一种实施方式基于该终端设备的上下文接入该第一接入网设备的第一小区。
在一种可能的实施方式中，该终端设备的上下文包括该第一小区的小区标识信息。在这种情况下，若该终端设备接收到来自该第一接入网设备的该第一小区的小区标识信息，则该终端设备基于该第一小区的小区标识信息接入该第一小区。
本实施方式中，终端设备的上下文存储的第一小区的小区标识信息，表示该第一小区是该终端设备曾经接入过的小区(例如，第一接入网设备曾经为终端设备提供服务时该终端设备接入的小区)，该终端设备的上下文可能记录有该终端设备接入该第一小区的相关配置信息，因此，该终端设备将有较高的几率基于该终端设备的上下文接入该第一小区，有利于提高终端设备接入第一接入网设备的效率。
在另一种可能的实施方式中，该终端设备接收来自该第一接入网设备的第二指示信息，该第二指示信息用于指示该终端设备发起接入；该终端设备基于该第二指示信息接入该第一接入网设备的该第一小区。
本实施方式中，终端设备能够在第一接入网设备发送的第二指示信息的指示作用下接入第一接入网设备，有利于提高终端设备接入第一接入网设备的效率。
在另一类可能的实施方式中，该第二接入网设备与该第一接入网设备为不同的接入网设备。该终端设备可以基于如下任意一种实施方式基于该终端设备的上下文接入该第二接入网设备。
在一种可能的实施方式中，该终端设备的上下文包括第一小区的小区标识信息。若该终端设备接收到来自该第二接入网设备的该第一小区的小区标识信息，则该终端设备基于该第一小区的小区标识信息接入该第二接入网设备的第二小区。
本实施方式中，第二接入网设备在系统消息中广播第一小区的小区标识信息，以指示曾经接入过第一小区的终端设备接入到第二接入网设备，有利于提高终端设备接入第二接入网设备的效率。
在另一种可能的实施方式中，该终端设备接收来自该第二接入网设备的第三指示信息，该第三指示信息用于指示该终端设备发起接入；该终端设备基于该第三指示信息接入该第二接入网设备的第二小区。
本实施方式中，终端设备能够在第二接入网设备发送的第三指示信息的指示作用下接入第二接入网设备，有利于提高终端设备接入第二接入网设备的效率。
在一种可能的实施方式中，该终端设备根据该第一指示信息存储该终端设备的上下文之前，该方法还包括：该终端设备从该第一接入网设备接收第一标识信息，该第一标识信息用于针对该第一接入网设备唯一标识该终端设备。
可选的，第一标识信息用于第一接入网设备在运行轨道上的不同位置唯一标识终端设备。也就是说，无论第一接入网设备移动到轨道的哪个位置，第一接入网设备为哪些终端设备配置了标识，该第一标识信息均能够唯一标识终端设备。可选的，第一标识信息的长度大于小区无线网络临时标识的长度。
本实施方式中，终端设备能够收到第一接入网设备为终端设备配置的第一标识信息，有利于后续信令交互过程中，第一接入网设备快速查找到与终端设备相关的信息(例如，该终端设备的上下文以及该终端设备的NAS消息等)。
在一种可能的实施方式中，该第一接入网设备停止为该终端设备提供服务之前，该方法还包括：该终端设备向该第一接入网设备发送该终端设备的上行NAS消息；该终端设备基于该终端设备的上下文与该第二接入网设备建立连接之后，该方法还包括：该终端设备向该第二接入网设备发送该第一标识信 息，该第一标识信息用于该第二接入网设备确定该终端设备的上下文；该终端设备从该第二接入网设备接收该终端设备的下行NAS消息。
在一种可能的实施方式中，该第一接入网设备停止为该终端设备提供服务之前，该方法还包括：该终端设备在发送上行NAS消息时启动第一NAS定时器，该第一NAS定时器为接入网设备不能与核心网设备交互信息时使用的NAS定时器；或者，该终端设备在发送上行NAS消息之后的第一时长之后启动第二NAS定时器，该第二NAS定时器为接入网设备能够与核心网设备交互信息时使用的NAS定时器。
可选的，第一NAS定时器的时长大于第二NAS定时器的时长，第二NAS定时器的时长可以是协议预定义的，也可以是预配置的，此处不做限定。
本实施方式中，通过设置时长更长的第一NAS定时器或延迟启动第二NAS定时器的方式，能够延长终端设备等待核心网设备反馈的下行NAS消息的时长，有利于推迟终端设备因NAS定时器(例如，第一NAS定时器或第二NAS定时器)超时而导致终端设备触发小区重选等流程，以使得终端设备处于等待下行NAS消息的状态。
在一种可能的实施方式中，该方法还包括：该终端设备接收来自该第一接入网设备的第一时间信息，该第一时间信息用于确定该第一NAS定时器的时长或者该第一时长。然后，终端设备基于该第一时间信息确定第一NAS定时器的时长或第一时长。
本实施方式中，提出终端设备可以基于来自第一接入网设备的第一时间信息确定第一NAS定时器的时长，有利于终端设备在接入网设备未与核心网设备建立连接时推迟终端设备因NAS定时器(例如，第一NAS定时器或第二NAS定时器)超时而导致终端设备触发小区重选等流程，以使得终端设备处于等待下行NAS消息的状态。
第二方面，本申请提供了一种通信方法，该通信方法可以由接入网设备执行，也可以由接入网设备的部件(例如，处理器、芯片或芯片系统等部件)执行。以第一接入网设备为例，第一接入网设备广播第一指示信息，该第一指示信息用于指示该第一接入网设备不能与核心网设备交互信息；当该第一接入网设备与终端设备建立连接之后，该第一接入网设备存储该终端设备的上下文，该终端设备的上下文为该第一接入网设备停止为该终端设备提供服务后，第二接入网设备接纳该终端设备使用的信息。
本申请中，第一接入网设备能够向终端设备提供第一指示信息，以使得终端设备能够基于来自第一接入网设备的第一指示信息确定该第一接入网设备未与核心网设备建立连接，进而促使该终端设备基于第一指示信息在与第一接入网设备建立连接的过程中(或建立连接之后)存储终端设备的上下文。与此同时，该第一接入网设备也将在与终端设备建立连接之后存储终端设备的上下文，有利于第一接入网设备利用存储的终端设备的上下文再次与终端设备建立连接，或者，第一接入网设备将该终端设备的上下文转发给第二接入网设备，由第二接入网设备利用存储的终端设备的上下文再次与终端设备建立连接。
在一种可能的实施方式中，该第一接入网设备广播第一指示信息，包括：该第一接入网设备在第一区域广播该第一指示信息，该第一区域为接入网设备不能与核心网设备建立连接的区域。
在一种可能的实施方式中，该第一接入网设备停止为所述终端设备提供服务之前，该方法还包括：该第一接入网设备在该第一区域接收来自该终端设备的上行NAS消息；该第一接入网设备存储该终端设备的上下文之后，该方法还包括：当该第一接入网设备移动至第二区域时，该第一接入网设备向该核心网设备发送该上行NAS消息，该第二区域为接入网设备能够与该核心网设备建立连接的区域。
在一种可能的实施方式中，该第二接入网设备为该第一接入网设备。该方法还包括：当该第一接入网设备再次移动至该第一区域时，该第一接入网设备基于该终端设备的上下文与该终端设备建立连接。
在一种可能的实施方式中，该第一接入网设备基于该终端设备的上下文与该终端设备建立连接，包括：该第一接入网设备基于该终端设备的上下文通过该第一接入网设备的第一小区为该终端设备提供服务，该第一小区为该第一接入网设备存储该终端设备的上下文时该终端设备接入的小区。
在一种可能的实施方式中，该第一接入网设备基于该终端设备的上下文与该终端设备建立连接之前，该方法还包括：该第一接入网设备在该第一区域广播该第一小区的小区标识信息，该第一小区的小区标识信息用于该终端设备接入该第一小区。
在一种可能的实施方式中，该第一接入网设备基于该终端设备的上下文与该终端设备建立连接之前，该方法还包括：该第一接入网设备在该第一小区向该终端设备发送第二指示信息，该第二指示信息用于指示该终端设备基于该终端设备的上下文发起接入。
在一种可能的实施方式中，该第一接入网设备向该核心网设备发送该上行NAS消息之后，该方法还包括：该第一接入网设备在该第二区域从该核心网设备接收该终端设备的下行NAS消息；该第一接入网设备基于该终端设备的上下文与该终端设备建立连接之后，该方法还包括：该第一接入网设备向该终端设备发送该下行NAS消息。
在一种可能的实施方式中，该第一接入网设备在该第一区域接收来自该终端设备的上行NAS消息之前，该方法还包括：该第一接入网设备向该终端设备发送第一标识信息，该第一标识信息用于针对该第一接入网设备唯一标识该终端设备；该第一接入网设备向该终端设备发送该下行NAS消息之前，该方法还包括：该第一接入网设备从该终端设备接收该第一标识信息；该第一接入网设备基于该终端设备的第一标识信息确定该终端设备的上下文；该第一接入网设备基于该终端设备的上下文确定该下行NAS消息。
在一种可能的实施方式中，该终端设备的上下文包括该终端设备的地理区域信息；该第一接入网设备向该终端设备发送该下行NAS消息之前，该方法还包括：该第一接入网设备基于该终端设备的小区无线网络临时标识和该终端设备的地理区域信息确定该终端设备的上下文；该第一接入网设备基于该终端设备的上下文确定该下行NAS消息。
在一种可能的实施方式中，该终端设备的上下文包括该终端设备接入该第一接入网设备的时间信息；该第一接入网设备向该终端设备发送该下行NAS消息之前，该方法还包括：该第一接入网设备基于该终端设备的小区无线网络临时标识和该终端设备接入该第一接入网设备的时间信息确定该终端设备的上下文；该第一接入网设备基于该终端设备的上下文确定该下行NAS消息。
在一种可能的实施方式中，该第二接入网设备与该第一接入网设备为不同的接入网设备；该第一接入网设备存储该终端设备的上下文之后，该方法还包括：当该第一接入网设备移动至第二区域时，该第一接入网设备向该核心网设备发送该终端设备的上下文，该第二区域为接入网设备能够与该核心网设备建立连接的区域，该终端设备的上下文用于该核心网设备确定的第二接入网设备与该终端设备建立连接。
在一种可能的实施方式中，该第一接入网设备在第一区域接收来自终端设备的上行NAS消息之前，该方法还包括：该第一接入网设备在该第一区域广播第一时间信息，该第一时间信息用于确定第一NAS定时器。
在一种可能的实施方式中，该方法还包括：当该第一接入网设备移动至第二区域时，该第一接入网设备向该核心网设备发送第四指示信息，该第四指示信息用于指示该终端设备是在该第一接入网设备不能与该核心网设备建立连接时接入到该第一接入网设备。
在一种可能的实施方式中，该方法还包括：当该第一接入网设备移动至第二区域时，该第一接入网设备向该核心网设备发送第一时间信息，该第一时间信息用于确定核心网设备的第一NAS定时器。
需要说明的是，本方面的具体实施方式和有益效果与前文第一方面中的部分实施方式类似，具体可参见第一方面的具体实施方式和其有益效果，在此不再赘述。
第三方面，本申请提供了一种通信方法，该通信方法可以由核心网设备执行，也可以由核心网设备的部件(例如，处理器、芯片或芯片系统等部件)执行。以核心网设备为例，核心网设备从第一接入网设备接收终端设备的上行NAS消息和第四指示信息，该第四指示信息用于指示该终端设备在该第一接入网设备不能与该核心网设备建立连接时接入到该第一接入网设备，该第四指示信息还用于该核心网设备在发送下行NAS消息时启动第一NAS定时器。
在一种可能的实施方式中，该方法还包括：该核心网设备从该第一接入网设备接收第一时间信息，该第一时间信息用于确定该第一NAS定时器。
在一种可能的实施方式中，该方法还包括：该核心网设备向该第一接入网设备发送该终端设备的下行NAS消息，并且，该核心网设备启动该第一NAS定时器；在该第一NAS定时器超时之前，该核心网设备从该第一接入网设备接收该下行NAS消息对应的上行NAS消息。
在一种可能的实施方式中，该方法还包括：该核心网设备向第二接入网设备发送该终端设备的下行NAS消息，并且，该核心网设备启动该第一NAS定时器，该第二接入网设备为即将移动至该终端设备所在的地理区域的接入网设备；在该第一NAS定时器超时之前，该核心网设备接收该下行NAS消息对应的上行NAS消息。
在一种可能的实施方式中，该方法还包括：该核心网设备从该第一接入网设备接收该终端设备的上下文；该核心网设备在向该第二接入网设备发送该终端设备的上下文。
需要说明的是，本方面的具体实施方式和有益效果与前文第一方面中的部分实施方式类似，具体可参见第一方面的具体实施方式和其有益效果，在此不再赘述。
第四方面，本申请提供了一种通信方法，该通信方法可以由接入网设备执行，也可以由接入网设备的部件(例如，处理器、芯片或芯片系统等部件)执行。以第二接入网设备为例，第二接入网设备从核心网设备接收终端设备的上下文和该终端设备的下行NAS消息；该第二接入网设备基于该终端设备的上下文确定该终端设备所在的地理区域；当该第二接入网设备移动至该终端设备所在的地理区域时，该第二接入网设备向该终端设备发送第二指示信息，该第二指示信息用于指示该终端设备发起随机接入；该第二接入网设备在该终端设备接入之后，向该终端设备发送该终端设备的下行NAS消息。
在一种可能的实施方式中，向该终端设备发送该终端设备的下行NAS消息之前，该方法还包括：该第二接入网设备从该终端设备接收第一标识信息，该第一标识信息用于针对该第一接入网设备唯一标识该终端设备；该第二接入网设备基于该第一标识信息确定该终端设备的上下文；该第二接入网设备基于该终端设备的上下文确定该下行NAS消息。
在一种可能的实施方式中，该终端设备的上下文包括该终端设备的地理区域信息；该第二接入网设备向该终端设备发送该下行NAS消息之前，该方法还包括：该第二接入网设备基于该终端设备的小区无线网络临时标识和该终端设备的地理区域信息确定该终端设备的上下文；该第二接入网设备基于该终端设备的上下文确定该下行NAS消息。
在一种可能的实施方式中，该终端设备的上下文包括该终端设备接入第一接入网设备的时间信息；该第二接入网设备向该终端设备发送该下行NAS消息之前，该方法还包括：该第二接入网设备基于该终端设备的小区无线网络临时标识和该终端设备接入该第一接入网设备的时间信息确定该终端设备的上下文；该第二接入网设备基于该终端设备的上下文确定该下行NAS消息。
需要说明的是，本方面的具体实施方式和有益效果与前文第一方面中的部分实施方式类似，具体可参见第一方面的具体实施方式和其有益效果，在此不再赘述。
第五方面，本申请提供了一种通信方法，该通信方法可以由核心网设备执行，也可以由核心网设备的部件(例如，处理器、芯片或芯片系统等部件)执行。以核心网设备为例，核心网设备根据终端设备的地理区域信息确定至少一个接入网设备，该接入网设备当前的覆盖区域不包括该终端设备所在的地理区域，该接入网设备的覆盖区域的移动路径经过该终端设备所在的地理区域；该核心网设备向该至少一个接入网设备发送寻呼消息，该寻呼消息包括该终端设备的地理区域信息。
其中，终端设备的地理区域信息用于指示该终端设备所在的地理区域。终端设备的地理区域信息可以存储于核心网设备中的终端设备的上下文中。例如，终端设备在注册到核心网设备之后，核心网设备建立终端设备的上下文。
本实施例中，核心网设备能够基于终端设备的地理区域信息确定至少一个用于寻呼终端设备的接入网设备，而不是直接基于TA列表确定用于寻呼终端设备的接入网设备，有利于提高核心网设备成功寻呼终端设备的几率。
在一种可能的实施方式中，该方法还包括：核心网设备在发送该寻呼消息时，该核心网设备启动第一寻呼定时器，该第一寻呼定时器的时长大于预配置的寻呼定时器的时长。
若在第一寻呼定时器的运行期间核心网设备能够收到终端设备的响应消息，则核心网设备寻呼终端设备成功；若在第一寻呼定时器的运行期间核心网设备没有收到终端设备的响应消息，则核心网设备寻呼终端设备失败。
第六方面，本申请提供了一种通信方法，该通信方法可以由接入网设备执行，也可以由接入网设备 的部件(例如，处理器、芯片或芯片系统等部件)执行。以第三接入网设备为例，第三接入网设备接收寻呼消息，该寻呼消息包括该终端设备的地理区域信息；当该第三接入网设备移动至该终端设备所在的地理区域时，该第三接入网设备在该终端设备所在的地理区域广播该寻呼消息。
在一种可能的实施方式中，该方法还包括：该第三接入网设备向第四接入网设备发送第五指示信息，该第四接入网设备为在该第三接入网设备停止为该终端设备提供服务后为该终端设备提供服务的接入网设备，该第五指示信息用于指示该第四接入网设备删除用于寻呼该终端设备的寻呼消息。
本实施方式中，若第三接入网设备与第四接入网设备之间存在星间链路，当第三接入网设备未成功寻呼终端设备时，第四接入网设备继续寻呼终端设备；当第三接入网设备成功寻呼终端设备时，第三接入网设备向第四接入网设备发送第五指示信息，第五指示信息用于指示第四接入网设备删除用于寻呼终端设备的寻呼消息。由于，能够减少终端设备接收寻呼消息的次数，因此，有利于节省终端设备的电能。
第七方面，本申请提供了一种通信方法，该通信方法可以由核心网设备执行，也可以由核心网设备的部件(例如，处理器、芯片或芯片系统等部件)执行。以核心网设备为例，核心网设备向第五接入网设备发送终端设备的多个数据包，每个该数据包对应一个第一序列号；该核心网设备向第六接入网设备发送该终端设备的上下文和该终端设备的多个数据包，该第六接入网设备为在该第五接入网设备停止为该终端设备提供服务后为该终端设备提供服务的接入网设备，该终端设备的上下文用于该第六接入网设备与该终端设备建立连接并向该终端设备发送该终端设备的多个数据包。
本实施方式中，由于核心网设备能够复制终端设备的多个数据包并向多个接入网设备发送该终端设备的数据包，以及向多个接入网设备发送终端设备的上下文。进而当其中一个接入网设备不能将全部的数据包发送给终端设备时，能够通过其他的接入网设备将数据包发送给终端设备。有利于保持终端设备接收的数据的连续性。
第八方面，本申请提供了一种通信方法，该通信方法可以由接入网设备执行，也可以由接入网设备的部件(例如，处理器、芯片或芯片系统等部件)执行。以第五接入网设备为例，第五接入网设备从核心网设备接收终端设备的多个数据包，每个该数据包对应一个第一序列号；当该第五接入网设备移动至该终端设备所在的地理区域时，该第五接入网设备基于该第一序列号向该终端设备发送携带该第一序列号的该数据包；或者，当该第五接入网设备移动至该终端设备所在的地理区域时，该第五接入网设备基于每个该数据包的该第一序列号和第一映射规则确定每个该数据包的第二序列号，以及，基于该第二序列号向该终端设备发送携带该第二序列号的该数据包。
在一种可能的实施方式中，该方法还包括：该第五接入网设备在停止为该终端设备提供服务之前，向该终端设备发送第六指示信息，该第六指示信息用于指示存在待发送的数据包。
第九方面，本申请提供了一种通信方法，该通信方法可以由接入网设备执行，也可以由接入网设备的部件(例如，处理器、芯片或芯片系统等部件)执行。以第六接入网设备为例，第六接入网设备从核心网设备接收终端设备的多个数据包和该终端设备的上下文，每个该数据包对应一个第一序列号；该第六接入网设备基于该终端设备的上下文与该终端设备建立连接；该第六接入网设备从该终端设备接收第七指示信息，该第七指示信息用于指示该终端设备已连续成功接收的数据包；该第六接入网设备基于该第七指示信息向该终端设备发送该多个数据包中的至少一个数据包。
在一种可能的实施方式中，该第七指示信息包括目标序列号，该目标序列号为该终端设备已连续确认接收的最后一个数据包的序列号。
在一种可能的实施方式中，该目标序列号为第一序列号；该第六接入网设备基于该目标序列号向该终端设备发送该多个数据包中的至少一个数据包，包括：该第六接入网设备向该终端设备发送携带该第一序列号的至少一个数据包，该至少一个数据包中每个数据包的第一序列号大于该目标序列号。
在一种可能的实施方式中，该目标序列号为第二序列号；该第六接入网设备基于该目标序列号向该终端设备发送该多个数据包中的至少一个数据包，包括：该第六接入网设备基于每个该数据包的该第一序列号和第一映射规则确定每个该数据包的第二序列号；该第六接入网设备向该终端设备发送携带该第二序列号的至少一个数据包，该至少一个数据包中每个数据包的第二序列号大于该目标序列号。
第十方面，本申请提供了一种通信方法，该通信方法可以由终端设备执行，也可以由终端设备的部 件(例如，处理器、芯片或芯片系统等部件)执行。以终端设备为例，终端设备从第五接入网设备接收至少一个数据包，每个该数据包对应一个第一序列号或第二序列号；在该第五接入网设备停止为该终端设备提供服务之后，该终端设备与该第六接入网设备建立连接；该终端设备向该第六接入网设备发送第七指示信息，该第七指示信息用于指示该终端设备已连续成功接收的数据包；该终端设备从该第六接入网设备接收至少一个数据包。
在一种可能的实施方式中，该第七指示信息包括目标序列号，该目标序列号为该终端设备已连续确认接收的最后一个数据包的序列号。
在一种可能的实施方式中，在该第五接入网设备停止为该终端设备提供服务之前，该方法还包括：该终端设备从该第五接入网设备接收第六指示信息，该第六指示信息用于指示存在待发送的数据包。
第十一方面，本申请实施例提供了一种通信装置，该通信装置可以是前述实施方式中的终端设备，也可以是该终端设备内的芯片。该通信装置可以包括处理模块和收发模块。当该通信装置是终端设备时，该处理模块可以是处理器，该收发模块可以是收发器；该终端设备还可以包括存储模块，该存储模块可以是存储器；该存储模块用于存储指令，该处理模块执行该存储模块所存储的指令，以使该终端设备执行第一方面或第一方面的任一种实施方式中的方法；或者，执行第十方面或第十方面的任一种实施方式中的方法。当该通信装置是终端设备内的芯片时，该处理模块可以是处理器，该收发模块可以是输入/输出接口、管脚或电路等；该处理模块执行存储模块所存储的指令，以使该终端设备执行第一方面或第一方面的任一种实施方式中的方法；或者，执行第十方面或第十方面的任一种实施方式中的方法。该存储模块可以是该芯片内的存储模块(例如，寄存器、缓存等)，也可以是该终端设备内的位于该芯片外部的存储模块(例如，只读存储器、随机存取存储器等)。
第十二方面，本申请实施例提供了一种通信装置，该通信装置可以是前述实施方式中的接入网设备，也可以是该接入网设备内的芯片。其中，该接入网设备可以是前述各方面介绍的第一接入网设备、第二接入网设备、第三接入网设备、第四接入网设备、第五接入网设备以及第六接入网设备等。该通信装置可以包括处理模块和收发模块。当该通信装置是接入网设备时，该处理模块可以是处理器，该收发模块可以是收发器；该接入网设备还可以包括存储模块，该存储模块可以是存储器；该存储模块用于存储指令，该处理模块执行该存储模块所存储的指令，以使得第一接入网设备执行第二方面或第二方面的任一种实施方式中的方法；或者，以使得第二接入网设备执行第四方面或第四方面的任一种实施方式中的方法；或者，以使得第三接入网设备执行第六方面或第六方面的任一种实施方式中的方法；或者，以使得第五接入网设备执行第八方面或第八方面的任一种实施方式中的方法；或者，以使得第六接入网设备执行第九方面或第九方面的任一种实施方式中的方法。当该通信装置是接入网设备内的芯片时，该处理模块可以是处理器，该收发模块可以是输入/输出接口、管脚或电路等；该处理模块执行存储模块所存储的指令，以使得第一接入网设备执行第二方面或第二方面的任一种实施方式中的方法；或者，以使得第二接入网设备执行第四方面或第四方面的任一种实施方式中的方法；或者，以使得第三接入网设备执行第六方面或第六方面的任一种实施方式中的方法；或者，以使得第五接入网设备执行第八方面或第八方面的任一种实施方式中的方法；或者，以使得第六接入网设备执行第九方面或第九方面的任一种实施方式中的方法。该存储模块可以是该芯片内的存储模块(例如，寄存器、缓存等)，也可以是该接入网设备内的位于该芯片外部的存储模块(例如，只读存储器、随机存取存储器等)。
第十三方面，本申请实施例提供了一种通信装置，该通信装置可以是前述实施方式中的核心网设备，也可以是该核心网设备内的芯片。该通信装置可以包括处理模块和收发模块。当该通信装置是核心网设备时，该处理模块可以是处理器，该收发模块可以是收发器；该核心网设备还可以包括存储模块，该存储模块可以是存储器；该存储模块用于存储指令，该处理模块执行该存储模块所存储的指令，以使该核心网设备执行第三方面或第三方面的任一种实施方式中的方法；或者，执行第五方面或第五方面的任一种实施方式中的方法；或者，执行第七方面或第七方面的任一种实施方式中的方法。当该通信装置是核心网设备内的芯片时，该处理模块可以是处理器，该收发模块可以是输入/输出接口、管脚或电路等；该处理模块执行存储模块所存储的指令，以使该核心网设备执行第三方面或第三方面的任一种实施方式中的方法；或者，执行第五方面或第五方面的任一种实施方式中的方法；或者，执行第七方面或第七方面 的任一种实施方式中的方法。该存储模块可以是该芯片内的存储模块(例如，寄存器、缓存等)，也可以是该核心网设备内的位于该芯片外部的存储模块(例如，只读存储器、随机存取存储器等)。
第十四方面，本申请提供了一种通信装置，该装置可以是集成电路芯片。该集成电路芯片包括处理器。该处理器与存储器耦合，该存储器用于存储程序或指令，当该程序或指令被该处理器执行时，使得该通信装置执行如前述各个方面的中的任一种实施方式所介绍的方法。
第十五方面，本申请实施例提供了一种包含指令的计算机程序产品，当其在计算机上运行时，使得该计算机执行如前述各个方面中的任一种实施方式所介绍的方法。
第十六方面，本申请实施例提供了一种计算机可读存储介质，包括指令，当该指令在计算机上运行时，以使得计算机执行如前各个方面中的任一种实施方式所介绍的方法。
第十七方面，本申请实施例提供了一种通信系统，该通信系统包括执行前述第一方面以及第一方面的任一种实施方式中的终端设备，执行前述第二方面以及第二方面的任一种实施方式中的第一接入网设备，执行前述第三方面以及第三方面的任一种实施方式中的核心网设备，以及，执行前述第四方面以及第四方面的任一种实施方式中的第二接入网设备。
第十八方面，本申请实施例提供了一种通信系统，该通信系统包括终端设备，执行前述第五方面以及第五方面的任一种实施方式中的核心网设备，以及，执行前述第六方面以及第六方面的任一种实施方式中的第三接入网设备。
第十九方面，本申请实施例提供了一种通信系统，该通信系统包括执行前述第七方面以及第七方面的任一种实施方式中的核心网设备，执行前述第八方面以及第八方面的任一种实施方式中的第五接入网设备，执行前述第九方面以及第九方面的任一种实施方式中的第六接入网设备，以及，执行前述第十方面以及第十方面的任一种实施方式中的终端设备。
附图说明
图1A为本申请的通信方法适用的一个网络架构图；
图1B为本申请的通信方法适用的另一个网络架构图；
图1C为本申请的通信方法适用的另一个网络架构图；
图1D为本申请的通信方法的应用场景的一个示例图；
图2为本申请的通信方法的一个流程图；
图3为本申请的通信方法的另一个流程图；
图4A为本申请的通信方法的应用场景的另一个示例图；
图4B为本申请的通信方法的应用场景的另一个示例图；
图5为本申请的通信方法的另一个流程图；
图6A为本申请的通信方法的应用场景的另一个示例图；
图6B为本申请的通信方法的应用场景的另一个示例图；
图7为本申请的通信方法的另一个流程图；
图8为本申请的通信方法的另一个流程图；
图9为本申请中通信装置的一个实施例示意图；
图10为本申请中通信装置的另一个实施例示意图；
图11为本申请中通信装置的另一个实施例示意图；
图12为本申请中通信装置的另一个实施例示意图。
具体实施方式
下面将结合本申请实施例中的附图，对本申请实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例仅仅是本申请一部分实施例，而不是全部的实施例。
本申请的说明书和权利要求书及上述附图中的术语“第一”、“第二”、“第三”、“第四”等(如果存在)是用于区别类似的对象，而不必用于描述特定的顺序或先后次序。应该理解这样使用的术语在 适当情况下可以互换，以便这里描述的实施例能够以除了在这里图示或描述的内容以外的顺序实施。此外，术语“包括”和“具有”以及他们的任何变形，意图在于覆盖不排他的包含，例如，包含了一系列步骤或单元的过程、方法、系统、产品或设备不必限于清楚地列出的那些步骤或单元，而是可包括没有清楚地列出的或对于这些过程、方法、产品或设备固有的其它步骤或单元。
应理解，本文中术语“和/或”，仅仅是一种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这三种情况。另外，本文中字符“/”，一般表示前后关联对象是一种“或”的关系。
为便于理解，下面先对本申请提出的通信方法的系统架构和应用场景进行介绍：
本申请提出的通信方法可以应用于长期演进(long term evolution，LTE)系统、5G NR(5G New Radio)系统、第六代的移动信息技术(the 6th generation mobile communication technology，6G)系统以及后续演进制式中，本申请对此不作限定。如图1A所示，该通信系统至少包括终端设备、接入网设备和核心网设备。
其中，终端设备，包括向用户提供语音和/或数据连通性的设备。例如，可以包括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处理设备。该终端设备可以经无线接入网(radio access network，RAN)与核心网(例如，5G核心网(5th generationcore，5GC))进行通信，可以与RAN交换语音和/或数据。该终端设备也可以被称为终端(Terminal)、用户设备(user equipment，UE)、无线终端设备、移动终端(mobile terminal，MT)设备、用户单元(subscriber unit)、用户站(subscriber station)，移动站(mobile station，MS)、移动台(mobile)、远程站(remote station)、接入点(access point，AP)、远程终端设备(remote terminal)、接入终端设备(access terminal)、用户终端设备(user terminal)、用户代理(user agent)、或用户装备(user device)等。此外，该终端设备可以是手机(mobile phone)、平板电脑(Pad)、带无线收发功能的电脑、虚拟现实(virtual reality，VR)终端设备、增强现实(augmented reality，AR)终端设备、工业控制(industrial control)中的无线终端、无人驾驶(self-driving)中的无线终端、远程手术(remote medical surgery)中的无线终端、智能电网(smart grid)中的无线终端、运输安全(transportation safety)中的无线终端、智慧城市(smart city)中的无线终端、智慧家庭(smart home)中的无线终端等等。应理解，本申请的实施例对终端设备所采用的具体技术和具体设备形态不做限定。本申请中的终端设备可以是上述任意一种设备或芯片，具体此处不做限定。无论作为设备还是作为芯片，该终端设备都可以作为独立的产品进行制造、销售或者使用。在本实施例以及后续实施例中，以终端设备为例进行介绍。
接入网设备，可以是任意一种具有无线收发功能的设备，可以用于负责空中接口相关的功能，例如，无线链路维护功能、无线资源管理功能、部分移动性管理功能。此外，该接入网设备还可以配置有基带单元(base band unit，BBU)，具备基带信号处理功能。示例性的，接入网设备可以是当前为终端设备提供服务的接入网设备(radio access network，RAN)。目前，接入网设备的一些常见示例为：节点B(Node B，NB)、演进型节点B(evolved Node B，eNB)、5G新无线(new radio，NR)系统中的下一代节点B(next generation node B，gNB)、6G系统中的节点(例如，xNodeB)、传输接收点(transmission reception point，TRP)、无线网络控制器(radio network controller，RNC)、基站控制器(base station controller，BSC)、基站收发台(base transceiver station，BTS)、家庭基站(例如，家庭演进节点(home evolved NodeB)或家庭节点(home Node B，HNB))等。此外，在云接入网(cloud radio access network，CloudRAN)或开放式接入网(open radio access network，ORAN)等网络结构中，接入网设备可以是包括集中式单元(centralized unit，CU)(也被称为控制单元)和/或分布式单元(distributed unit，DU)的设备。其中，包括CU和DU的RAN设备将NR系统中gNB的协议层拆分开，部分协议层的功能放在CU集中控制，剩下部分或全部协议层的功能分布在DU中，由CU集中控制DU。应理解，本申请实施例中的接入网设备可以是上述任意一种设备或上述设备中的芯片，具体此处不做限定。无论作为设备还是作为芯片，该接入网设备都可以作为独立的产品进行制造、销售或者使用。在本实施例以及后续实施例中，以接入网设备为例进行介绍。在NTN中，接入网设备可以包括卫星和NTN网关。
可选的，当接入网设备是由CU和DU构成时，多个DU可以共用一个CU。CU和DU的切分可以按照 协议栈切分。例如，如图1A所示，一种可能的方式是将无线资源控制(radio resource control，RRC)、服务数据适应协议(service data adaptation protocol，SDAP)以及分组数据汇聚协议(packet data convergence protocol，PDCP)层部署在CU中，其余的无线链路控制(radio link control，RLC)层、介质访问控制(media access control，MAC)层以及物理层(physical，PHY)部署在DU中。CU和DU之间通过F1接口连接。CU代表gNB通过NG接口和核心网连接，CU代表gNB通过Xn接口和其他gNB连接，CU还可以代表gNB通过X2口和其他eNB连接执行双连接操作。进一步地，CU还可以划分为控制面(CU-CP)和用户面(CU-UP)。其中，CU-CP负责控制面功能，主要包含RRC和控制面对应的PDCP(即PDCP-C)。PDCP-C主要负责控制面数据的加解密、完整性保护以及数据传输等。CU-UP负责用户面功能，主要包含SDAP和用户面对应的PDCP(即PDCP-U)。其中，SDAP主要负责将核心网的数据进行处理并将flow映射到承载。PDCP-U主要负责数据面的加解密、完整性保护、头压缩、序列号维护以及数据传输等。其中，CU-CP和CU-UP通过E1接口连接。CU-CP代表gNB通过NG接口和核心网连接，通过F1接口控制面(即F1-C)和DU连接。CU-UP通过F1接口用户面(即F1-U)和DU连接。还有一种可能的实现是PDCP-C也在CU-UP中。CU的控制面CU-CP还包括一种进一步切分的架构，即将现有的CU-CP进一步切分为CU-CP1和CU-CP2。其中，CU-CP1包括各种无线资源管理功能(例如，移动性管理、为终端设备发送的下行RRC消息中各个信息的具体取值等)，CU-CP2仅包括RRC功能(例如，负责生成下行RRC消息和解码上行RRC消息)和PDCP-C功能(即控制面信令在PDCP层的基本功能)。
核心网设备，是指为终端设备提供业务支持的核心网(core network，CN)中的设备。目前，核心网设备的一些常见示例为：接入和移动性管理功能(access and mobility management function，AMF)实体、会话管理功能(session management function，SMF)实体、用户面功能(user plane function，UPF)实体等等，此处不一一列举。其中，AMF实体可以负责终端设备的接入管理和移动性管理；SMF实体可以负责会话管理，如用户的会话建立等；UPF实体可以是用户面的功能实体，主要负责连接外部网络。需要说明的是，本申请中实体也可以称为网元或功能实体。例如，AMF实体也可以称为AMF网元或AMF功能实体；又例如，SMF实体也可以称为SMF网元或SMF功能实体等。应注意，本申请中的核心网设备至少包括AMF实体。
示例性的，本申请提出的通信方法可以应用于非陆地通信网络NTN架构中。例如，3GPP协议中定义的基于NG-RAN架构的非陆地通信网络(NTN-based NG-RAN architectures)。此时，前述接入网设备中的部分或全部的功能可以通过非陆地通信网络设备(例如卫星，系留无人机(tethered unmanned aerial system，TUA)、比空气轻无人机(lighter than air，LTA)、比空气重无人机(heavier than air UAS，HTA)、高空通信平台(high altitude platform station，HAPS)中的至少一种)实现；或者，接入网设备通过非陆地通信网络设备为终端设备提供服务。需要说明的是，本申请以非陆地通信网络设备为卫星为例进行描述，但本申请并不限定。非陆地通信网络设备还可能是以上其他任何一种，即本发明中的描述的卫星还可以用以上任何一种非陆地通信网络设备替代。
本申请可以应用于基于再生卫星(regenerative satellite)的NG-RAN架构中。下面将分别对几种常见的基于再生卫星的NG-RAN架构的示例进行介绍：
如图1B所示，为不具有卫星间链路(inter-satellite link，ISL)(也可称为星间链路)的再生卫星(regenerative satellite without ISL)的NG-RAN架构的一种示例。其中，卫星作为接入网设备或者卫星具有接入网设备功能。在该网络结构中，终端设备通过与卫星间的服务链路(service link)向接入网设备(即卫星)发送Uu无线接口信号；相应地，卫星作为接入网设备从终端设备接收Uu无线接口信号，并将收到的信号解析处理。此外，卫星作为接入网设备通过馈电链路(feeder link)与地面的NTN网关交互信息，进而卫星通过地面的NTN网关与地面的核心网设备交互NG口信息。例如，卫星生成NG口信息，并通过地面的NTN网关向核心网设备发送NG口信息。类似的，核心网设备生成NG口信息，并通过地面的NTN网关向卫星发送NG口信息。在本示例中，卫星会产生如下信号：Uu无线接口的信号，NTN网关与卫星之间的馈电链路上的卫星无线接口(satellite radio interface，SRI)的信号。
如图1C所示，为具有卫星间链路的再生卫星(regenerative satellite with ISL)的RAN架构的一种示例。本示例中，卫星作为接入网设备或者卫星具有接入网设备功能。本示例中，地面终端设备、卫星、 NTN网关和核心网设备之间的关系与图1B所示示例类似，区别在于图1C所示示例中的两个卫星之间存在星间链路，可以通过星间链路交互Xn口信息。
在前述几种基于再生卫星的NG-RAN架构中，作为接入网设备的卫星可以通过服务链路与地面终端设备交互Uu口信令，还可能需要通过地面的NTN网关与核心网设备交互NG接口信令。然而，如图1D所示，当卫星所在的区域对应的地面没有部署NTN网关时，该卫星不能或无法通过NTN网关与核心网成功建立连接。在这种情况下，卫星的小区可能存在两种状态：1)卫星广播的系统消息指示小区状态为不能提供服务的小区(例如，系统消息指示的cell barred状态为barred状态)，终端设备无法接入该卫星(即未与核心网设备建立连接的卫星)，进而终端设备无法享受网络服务。2)卫星广播的系统消息指示小区状态可提供服务的小区(例如，系统消息指示的cellBarred状态为not barred状态)，但终端设备不感知卫星未与核心网建立连接，因此，该终端设备可能接入该卫星。由于，卫星不能或无法将终端设备的接入请求转发给核心网设备，因此，终端设备在接入该卫星后因不能收到核心网设备回复的下行NAS消息而在NAS定时器超时重新执行小区测量、小区重选等流程或无法完成连接所需的交互，导致终端设备处于寻找可接入的卫星的状态，而无法享受网络服务。
对此，本申请提出了一种通信方法、通信装置及系统，用于使得终端设备在接入未与核心网设备建立的接入网设备时也能够获得网络服务，而不至于处于断网的状态。
下面将结合图2对本申请提出的通信方法的主要流程进行介绍。本实施例涉及的接入网设备(例如，后文将介绍的第一接入网设备和第二接入网设备等)可以是卫星等非陆地通信网络设备。示例性的，本实施例适可以适用于图1B所示的NTN架构，即没有星间链路的再生卫星的RAN架构。本实施例也可以适用于图1B和图1C结合的NTN架构，即NTN间没有连续的星间链路，但是部分NTN间有星间链路的场景。例如，第一接入网设备与第二接入网设备之间没有星间链路，不进行信令交互。具体地，第一接入网设备、第二接入网设备和终端设备将执行如下步骤。
步骤201，第一接入网设备发送第一指示信息。
相应地，终端设备接收第一指示信息。
示例性的，第一接入网设备广播第一指示信息，终端设备接收来自第一接入网设备的第一指示信息。该第一指示信息可以携带于系统消息(例如，系统信息块1(system information block 1，SIB1)或主信息块(master information block，MIB)等)中。例如，第一接入网设备广播系统消息，终端设备接收系统消息获取前述第一指示信息。
其中，该第一指示信息用于指示第一接入网设备当前不能与核心网设备交互信息。可以理解为，第一指示信息用于指示第一接入网设备当前不能或无法通过NTN网关与核心网设备成功建立连接。例如，第一接入网设备当前所在区域没有NTN网关覆盖，导致第一接入网设备当前不能与NTN网关建立馈电链路(feeder link)，进而第一接入网设备当前不能或无法通过NTN网关与核心网设备交互信息。又例如，第一接入网设备当前所在区域的NTN网关出现故障，导致第一接入网设备当前不能与NTN网关建立馈电链路(feeder link)，进而第一接入网设备当前不能通过NTN网关与核心网设备交互信息。也可以理解为，第一指示信息用于指示第一接入网设备当前能通过NTN网关与核心网设备建立连接，但该连接存在故障或该连接过载导致第一接入网设备不能与核心网设备交互信息。例如，第一接入网设备当前所在区域的NTN网关无故障，第一接入网设备能够与NTN网关建立馈电链路(feeder link)，NTN网关也能够与核心网设备建立连接，但是，由于配置信息错误或馈电链路的信号质量太差，导致该第一接入网设备不能通过该NTN网关与核心网交互信息。
需要说明的是，一种可能实施中，第一指示信息仅指示该第一接入网设备当前没有与核心网设备成功建立连接，但是，该第一接入网设备具有与核心网设备建立连接的能力，该第一接入网设备在未来可能与核心网设备建立连接。例如，当第一接入网设备移动至有NTN网关覆盖的区域时，该第一接入网设备能够通过NTN网关与核心网设备建立连接。另一种可能实施中，第一指示信息仅指示该第一接入网设备当前不能或无法与核心网设备交互信息，但是，该第一接入网设备具有与核心网设备建立连接的能力，该第一接入网设备在未来可能与核心网设备建立连接。例如，当第一接入网设备移动至有NTN网关覆盖的区域时，该第一接入网设备能够通过NTN网关与核心网设备建立连接。另一种可能实施中， 第一指示信息仅指示该第一接入网设备当前不能或无法与核心网设备交互信息，但该第一接入网设备已经与核心网设备建立连接。例如，第一接入网设备之前通过NTN网关与核心网设备建立连接，但当第一接入网设备当前移动至终端设备所在区域时，该所在区域没有可用的NTN网关，但当第一接入网设备移动至有NTN网关可用的区域时，该第一接入网设备又能够通过NTN网关与核心网设备交互信息。
示例性的，该第一指示信息可以是描述第一接入网设备的状态的标识信息，例如，无CN连接的标识。该第一指示信息也可以是描述数据传输模式的标识信息，例如，存储转发(store and forward)模式的标识。本申请中，第一接入网设备在不能与核心网设备交互信令时接收并保存来自终端设备的信令(例如NAS信令)或数据，待第一接入网设备移至能够与核心网设备交互信息的区域时再向核心网设备转发来自终端设备的信令或数据，将这种信令传输方式称为存储转发(store and forward)模式。存储转发(store and forward)模式也包括第一接入网设备在能与核心网设备交互信令时接收并保存来自核心网的关于终端设备的信令或数据，待第一接入网设备移至能覆盖该终端设备的区域时，第一接入网设备再向终端设备转发来核心网的关于该终端设备的信令或数据。Store and forward可以定义为NTN接入系统的一种操作模式，该模式中，NTN接入系统中无法提供与NTN网关连接的一个馈电链路，但仍然可以为接入网设备下面的用户提供通信服务。在实际应用中，还可以采用其他的标识信息或指示信息实现前述第一指示信息，本申请不限定第一指示信息的具体实现形式。
步骤202，终端设备与第一接入网设备建立连接。
终端设备收到来自第一接入网设备的第一指示信息之后，当终端设备需要获得网络服务时，该终端设备可以向第一接入网设备发起随机接入进而与第一接入网设备建立连接。可选的，若终端设备在第一接入网设备的第一小区收到第一指示信息，则该终端设备可以在第一小区发起随机接入。
需要说明的是，终端设备可以发起基于四步的随机接入来接入第一接入网设备，也可以发起基于两步的随机接入来接入第一接入网设备，具体本申请不做限定。
需要说明的是，在与接入网设备建立连接的过程中，终端设备先通过随机接入流程进行上行时间同步再进行RRC连接。在RRC连接建立过程中，第一接入网设备可以向终端设备分配该终端设备的标识信息，用于在终端设备与第一接入网设备之间的信令交互中唯一标识该终端设备。例如，该终端设备的标识信息是小区无线网络临时标识(cell radio network temporary identifier，C-RNTI)。此外，该第一接入网设备还会为终端设备配置该终端设备使用的资源。其中，前述资源包括但不限于时频资源(例如，小区组配置(CellgourpConfig)中的RLC资源、MAC资源和物理层资源(例如，物理小区组配置(PhysicalCellGroupConfig)中的物理资源)以及特殊小区配置(Spcellconfig)中用于上下行传输的资源等)以及承载资源(例如，信令无线承载0(signaling radio bearer 0，SRB0)、信令无线承载1(signaling radio bearer 1，SRB1)以及信令无线承载2(signaling radio bearer 2，SRB2)等)。
在终端设备与第一接入网设备之间的RRC连接建立完成时，即终端设备向第一接入网设备发送RRC建立完成(RRC Setup Complete)消息时，RRC Setup Complete携带了NAS消息(例如，第三代合作伙伴计划(third generation partnership project，3GPP)的技术规范(technical specification)TS 38.331中的dedicated NAS-Message信元)，该NAS消息是用于在终端设备和核心网设备之间传输终端设备特定的NAS层信息，RRC层仅透传该NAS消息。本申请中，将终端设备在RRC建立完成时向第一接入网设备发送的NAS消息称为上行NAS消息(一些场景中也称为初始NAS消息)。示例性的，在NR系统中，RRC Setup Complete上行NAS消息包括注册请求(Register Request)，该Regiseter Request用于向核心网发起初始注册请求。
步骤203，终端设备根据该第一指示信息存储终端设备的上下文。
应注意，终端设备可以在执行步骤202之后执行步骤203，也可以在执行步骤202的过程中执行步骤203，此处不做限定。
本步骤中，终端设备的上下文(UE context)包括终端设备接入第一接入网设备时使用的与接入层(access stratum，AS)相关的信息，也称为终端设备的AS上下文。示例性的，终端设备的上下文包括第一接入网设备为终端设备配置的终端设备的标识信息，例如，第一接入网设备配置的C-RNTI等；第一接入网设备为该终端设备配置的资源相关的信息，例如，第一接入网设备为终端设备配置的时频资源 相关的信息(例如，小区资源配置信息(cell group configuration))以及第一接入网设备为终端设备配置的承载相关的信息(例如，无线承载配置(radio bear configuration)中的SRB0、SRB1相关的信息等)；终端设备接入的小区的标识信息，例如，全球小区标识(cell global identifier，CGI)、物理小区标识(physical cell identifier，PCI)等。可选的，与AS相关的信息还包括终端设备接入第一接入网设备的时间信息、终端设备接入第一接入网设备的地理区域信息、终端设备接入第一接入网设备时第一接入网设备广播的TAC中的一种或多种。
可选的，终端设备的上下文还包括终端设备的非接入层(non-access stratum，NAS)相关的信息，也称为终端设备的NAS上下文。例如，终端设备已发送的上行NAS消息，终端设备已经启动的相关NAS定时器。
可选的，终端设备的上下文还包括第一指示信息。例如，终端设备的上下文包括无CN连接的标识或store and forward模式的标识，表示该终端设备接入的第一接入网设备当前无法向核心网转发终端设备的NAS消息。
可选的，终端设备的上下文是截止该第一接入网设备停止提供服务时的上下文。示例性的，从终端设备开始接入第一接入网设备时，该终端设备可以持续记录终端设备的上下文，终端设备成功接入第一接入网设备之后，该终端设备也会持续更新终端设备的上下文，直至第一接入网设备停止为终端设备提供服务。其中，第一接入网设备停止为终端设备提供服务可以为终端设备无法收到第一接入网设备的信号，或者终端设备向第一接入网设备发送RRC建立完成(RRC Setup Complete)消息之后，或者终端设备收到第一接入网设备发送的释放RRC消息之后。
可选的，第一接入网设备停止为终端设备提供服务时，如果终端设备没有收到第一接入网设备发送的释放RRC消息时，或者收到了第一接入网设备发送的释放RRC消息但该释放RRC消息中携带指示信息，指示终端设备保存上下文时，终端设备才会继续保存终端设备的上下文。
由于，终端设备能够基于来自第一接入网设备的第一指示信息确定该第一接入网设备不能与核心网交互信息，并且该终端设备基于第一指示信息在与第一接入网设备建立连接的过程中(或建立连接之后)存储终端设备的上下文。例如，该终端设备将从开始接入第一接入网设备时便持续记录终端设备的上下文，直至第一接入网设备停止为终端设备提供服务。因此，当该第一接入网设备停止为终端设备提供服务时，该终端设备的上下文中记载有终端设备接入第一接入网设备时使用的与接入相关的信息(例如，第一接入网设备配置的C-RNTI、SRB0以及SRB1相关的信息等)，有利于终端设备基于终端设备的上下文复用已有的与接入相关的配置接入到能够给终端设备提供服务的接入网设备(例如，后文将介绍的第二接入网设备)，不仅可以减少接入网设备为终端设备配置资源的信令开销，还可以提高终端设备接入接入网设备的效率，缩短终端设备与网络侧建立连接的时延。
步骤204，第一接入网设备存储终端设备的上下文。
应注意，第一接入网设备可以在执行步骤202之后执行步骤204，也可以在执行步骤202的过程中执行步骤204，此处不做限定。还应注意，步骤203与步骤204无明确的时间先后顺序的限定。例如，终端设备先执行步骤203，再由第一接入网设备执行步骤204。又例如，第一接入网设备先执行步骤204，再由终端设备执行步骤203。又例如，终端设备执行步骤203的同时，第一接入网设备执行步骤204。
本步骤中，终端设备的上下文包括终端设备接入第一接入网设备时配置给终端设备的接入层AS相关的信息；终端设备的上下文还包括终端设备接入第一接入网设备后发送给第一接入网并要透传给核心网的非接入层NAS相关的信息。可选的，终端设备的上下文是截止该第一接入网设备停止提供服务时的上下文。具体请参阅前文步骤203中的相关介绍，此处不予赘述。
需要说明的是，第一接入网设备存储的终端设备的上下文可以用于该第一接入网设备再次与该终端设备建立连接时使用；也可以发送给核心网设备，由核心网设备发送给其他可能为该终端设备提供服务的第二接入网设备，用于第二接入网设备与终端设备建立连接时使用。
还需要说明的是，当第一接入网设备的覆盖区域离开终端设备所在的地理区域时，该第一接入网设备停止为终端设备提供服务。在第一接入网设备停止为终端设备提供服务之后，该终端设备可以执行步骤205。
步骤205，终端设备基于终端设备的上下文与第二接入网设备建立连接。
步骤205为可选的步骤。
本步骤中，终端设备的上下文为该终端设备在第一接入网设备停止为该终端设备提供服务后接入第二接入网设备使用的信息。也就是说，当第一接入网设备停止为终端设备提供服务后，该终端设备可以利用该终端设备的上下文与第二接入网设备建立连接。
该第二接入网设备是具有该终端设备的上下文的接入网设备。例如，该第二接入网设备中存储有该终端设备的上下文。需要说明的是，该第二接入网设备具有的终端设备的上下文是终端设备接入第一接入网设备时第一接入网设备存储的终端设备上下文。
需要说明的是，第二接入网设备是移动到终端设备所在的地理区域的接入网设备。例如，在第一接入网设备离开终端设备所在的地理区域之后(也称为移出能为终端设备提供服务的物理区域之后)，即第一接入网设备无法继续为终端设备提供服务时，第二接入网设备移动到该终端设备所在的地理区域(也称为移动到能为该终端设备提供服务的地理区域)，即第二接入网设备可以为终端设备提供服务时，该终端设备可以接收到第二接入网设备的系统消息，进而该终端设备可以自主决策或在第二接入网设备指示下触发接入到该第二接入网设备。
还需要说明的是，第二接入网设备与第一接入网设备可以是同一接入网设备，也可以是不同的接入网设备。下面分别进行介绍：
在一类实施方式1中，第二接入网设备与第一接入网设备为同一接入网设备。例如，第一接入网设备在停止为终端设备提供服务的一段时长之后，该第一接入网设备再次移动到该终端设备所在的地理区域，进而该终端设备再次与第一接入网设备建立连接。在本类实施方式中，第二接入网设备存储的终端设备的上下文是第一接入网设备存储的终端设备的上下文(例如，第一接入网设备在步骤204存储的终端设备的上下文)。该终端设备可以通过如下任意一种实现方式触发建立与第一接入网设备(即第二接入网设备)之间的连接：
在本类实施方式1的一种实现方式1.1中，终端设备基于来自第一接入网设备的系统消息的内容决策是否触发接入第一接入网设备。具体地，第一接入网设备将在系统消息中广播该第一接入网设备的各个小区的小区标识信息，该终端设备接收前述各个小区的系统消息。若终端设备在系统消息中读取到的小区标识信息，与终端设备的上下文中存储的第一小区的小区标识信息相同，则该终端设备触发接入该第一接入网设备的第一小区。
本实现方式中，终端设备的上下文存储的第一小区的小区标识信息，表示该第一小区是该终端设备曾经接入过的小区(例如，第一接入网设备曾经为终端设备提供服务时该终端设备接入的小区)，该终端设备的上下文可能记录有该终端设备接入该第一小区的相关配置信息，因此，该终端设备将有较高的几率基于该终端设备的上下文接入该第一小区，有利于提高终端设备接入第一接入网设备的效率。
在本类实施方式1的另一种实现方式1.2中，终端设备基于来自第一接入网设备的指示信息触发接入第一接入网设备。具体地，第一接入网设备可以向终端设备发送第二指示信息。其中，第二指示信息用于指示该终端设备发起接入，也可以理解为，该第二指示信息用于指示终端设备触发接入到第一接入网设备。当该终端设备接收来自该第一接入网设备的第二指示信息之后，该终端设备基于第二指示信息触发接入该第一接入网设备。第一接入网设备可以仅发送一次第二指示信息，也可以周期性多次发送第一指示信息直到终端设备成功接入该第一接入网设备，本实施例对此不做限制。
可选的，该终端设备先与第一接入网设备的第一小区进行下行同步，接收第二指示信息，基于第二指示信息触发接入该第一接入网设备的第一小区。例如，第二指示信息可以是向终端设备发送的使用终端设备的标识信息(例如，C-RNTI或第一标识信息。其中，第一标识信息用于在第一接入网设备中唯一标识该终端设备。具体地，后文将在步骤302.4对第一标识信息进行详细介绍，此处不予赘述。)加扰的物理下行控制信道命令(physical downlink control channel order，PDCCH order)，该终端设备在第一小区收到第二指示信息，则该终端设备触发接入该第一小区。其中，第一小区是终端设备的上下文中存储的小区。
需要说明的是，第一接入网设备在哪个小区发送第二指示信息，该终端设备在哪个小区收到第二指 示信息便触发接入哪个小区。因此，终端设备前后两次可能接入第一接入网设备的同一个小区，也可能接入第一接入网设备的不同小区。
本实施例中，终端设备基于前述实现方式1.1或实现方式1.2触发接入第一接入网设备之后，由于，终端设备存储有终端设备的上下文，第一接入网设备存储有终端设备的上下文，因此，终端设备可以利用终端设备的上下文中接入第一接入网设备时使用的与AS相关的信息再次与第一接入网设备建立连接。具体地，终端设备向第一接入网设备的第一小区发起随机接入进行上行同步，上下行同步成功后终端设备和第一接入网设备使用终端设备的上下文中与AS相关的信息进行后续传输。也就是说，终端设备可以使用终端设备上次接入第一接入网设备时的资源配置(例如，时频资源配置和/或承载配置)进行后续传输，而无需再与第一接入网设备重新进行RRC的初始建立。其中，后续传输可以是交互NAS消息，可以是交互终端设备的配置。例如，终端设备与第一接入网设备完成上下行同步之后，该终端设备直接与第一接入网设备进行后续的NAS消息透传。又例如，终端设备与第一接入网设备完成上下行同步之后，第一接入网设备会先向终端设备发起用于更新当前终端设备的上下文中的配置的配置消息，更新成功后，终端设备与第一接入网设备再进行后续的NAS透传。
在另一类实施方式2中，第二接入网设备与第一接入网设备为不同的接入网设备。例如，第一接入网设备在停止为终端设备提供服务之后，第二接入网设备(例如，与该第一接入网设备具有相同运动轨迹的接入网设备)移动到能服务该终端设备的地理区域，进而该终端设备与第二接入网设备建立连接。具体的，第二接入网设备可以是第一接入网设备停止为终端设备提供服务之后就立即为终端设备提供服务，也可以第一接入网设备停止为终端设备提供服务之后过了一段时长后才为终端设备提供服务，对此不做限定。此外，第二接入网设备是继第一接入网设备之后移动到终端设备所在的地理区域的接入网设备，具体是继第一接入网设备之后第几个移动到终端设备所在的地理区域的接入网设备在此不做限定。在本类实施方式中，第二接入网设备存储的终端设备的上下文来自于第一接入网设备。例如，第一接入网设备存储了终端设备的上下文之后通过核心网设备转发给第二接入网设备。该终端设备可以通过如下任意一种实现方式触发建立与第二接入网设备之间的连接：
在本类实施方式2的一种实现方式2.1中，终端设备基于来自第二接入网设备的系统消息的内容决策是否触发接入第二接入网设备。具体地，第二接入网设备存储有终端设备的上下文，该终端设备的上下文包括第一小区的小区标识信息，该第一小区为终端设备曾经在第一接入网设备中接入的小区。该第二接入网设备在系统消息中广播第一小区的小区标识信息，用于指示接入过第一小区的终端设备触发接入该第二接入网设备。若终端设备在第二接入网设备的系统消息中收到第一小区的小区标识信息，而该终端设备的上下文又存储有第一小区的小区标识信息，说明该终端设备曾经接入过该第一小区，该第二接入网设备中的小区能够继续接替该第一小区为终端设备提供服务，则该终端设备触发基于存储的终端上下文，接入该第二接入网设备。
可选的，终端设备基于来自第二接入网设备的第一小区的小区标识信息接入该第二接入网设备的第二小区。其中，该第二小区是第二接入网设备广播第一小区的小区标识信息的小区。例如，第二接入网设备在第二小区广播第一小区的小区标识信息，该终端设备在第二小区收到第二指示信息便触发接入第二小区。
在本类实施方式2的另一种实现方式2.2中，终端设备基于来自第二接入网设备的指示信息触发接入第二接入网设备。具体地，第二接入网设备可以向终端设备发送第三指示信息。其中，第三指示信息用于指示该终端设备发起接入，也可以理解为，该第三指示信息用于指示终端设备触发接入到第二接入网设备。可选的，该第三指示信息也可以用于指示该第二接入网设备存储有该终端设备的上下文。当该终端设备接收来自该第二接入网设备的第三指示信息之后，该终端设备基于第三指示信息触发接入该第二接入网设备。第二接入网设备可以仅发送一次第三指示信息，也可以周期性多次发送第三指示信息直到终端设备成功接入该第二接入网设备，本实施例对此不做限制。
可选的，该终端设备基于第三指示信息触发接入该第二接入网设备的第二小区。例如，第二接入网设备在第二小区广播第三指示信息，该终端设备在第二小区收到第三指示信息，则该终端设备触发接入该第二小区。其中，第二小区可以是第二接入网设备中的任意一个小区。
可选的，该第三指示信息可以是向终端设备发送的使用终端设备的标识信息(例如，C-RNTI或第一标识信息)加扰的物理下行控制信道命令(PDCCH Order)；也可以是指示在终端设备的上下文中存储有第一小区的小区标识信息的终端设备的指示信息，例如，第三指示信息可以是第一小区的小区标识信息或指示第一小区的信息。
示例性的，当第二接入网设备中存储的多个终端设备的上下文中有多个终端设备曾经接入的小区的小区标识时，该第二接入网设备发送的第三指示信息可以是多个小区的小区标识信息，每个小区标识信息用于指示前述多个终端设备中对应的终端设备曾经接入的小区。
本实施例中，终端设备基于前述实现方式2.1或实现方式2.2触发接入第二接入网设备之后，由于，终端设备存储有终端设备的上下文，第二接入网设备存储有终端设备的上下文，因此，终端设备可以利用终端设备的上下文与第二接入网设备建立连接。具体地，终端设备向第二接入网设备的第二小区发起随机接入进行上行同步，上下行同步成功后终端设备和第二接入网设备使用终端设备的上下文中与AS相关的信息进行后续传输。
示例性的，终端设备向第二接入网设备发送随机接入前导，第二接入网设备在收到来自终端设备的随机接入前导之后向终端设备发送随机接入响应，进而第二接入网设备与终端设备完成上行时间同步。然后，终端设备可以利用上下文中时频资源相关的信息和承载相关的信息确定与第二接入网设备进行通信的时频资源和无线承载。可选的，终端设备可以基于前述时频资源和无线承载向第二接入网设备发送上行NAS消息，以使得第二接入网设备在能够与核心网设备建立连接时与核心网设备交互终端设备的NAS消息，进而使得终端设备能够接入网络。
本实施例中，终端设备能够基于来自第一接入网设备的第一指示信息确定该第一接入网设备未与核心网设备建立连接，并且，该终端设备基于第一指示信息在与第一接入网设备建立连接的过程中(或建立连接之后)存储终端设备的上下文。因此，当该第一接入网设备停止为终端设备提供服务时，该终端设备的上下文中记载有终端设备接入第一接入网设备时使用的与接入相关的信息(例如，第一接入网设备配置的C-RNTI、SRB0以及SRB1相关的信息等)，该终端设备能够继续使用终端设备上下文中的配置(例如，已为终端设备配置的时频资源和无线承载)与第二接入网设备继续进行通信，而不需要终端设备在第二接入网设备重新进行RRC的初始建立，因此，有利于节省与第二接入网设备建连的信令开销，有利于提高终端设备接入第二接入网设备的效率，进而缩短终端设备与网络侧建立连接的时延。
下面将结合图3对本申请提出的通信方法进行进一步介绍。本实施例中，第二接入网设备与第一接入网设备为同一接入网设备。例如，仅有第一接入网设备为终端设备提供服务。具体地，第一接入网设备、终端设备和核心网设备将执行如下步骤。
步骤301，第一接入网设备广播第一指示信息。
相应地，终端设备接收第一指示信息。关于第一指示信息的介绍请参阅前文步骤201，此处不予赘述。
可选的，第一接入网设备在第一区域广播第一指示信息，该第一区域为接入网设备不能与核心网设备交互信息的区域。示例性的，第一区域为没有NTN网关覆盖的区域，因此，在第一区域第一接入网设备无法通过NTN网关与核心网设备成功建立连接。该终端设备所在的地理区域位于所述第一区域中，即该终端设备所在的地理区域是没有NTN网关覆盖的区域。与该第一区域相对的概念为第二区域。第一接入网设备在第二区域不广播第一指示信息。该第二区域为接入网设备能够与核心网设备交互信息的区域。示例性的，第二区域为有NTN网关覆盖的区域，因此，在第二区域第一接入网设备能够通过NTN网关与核心网设备成功建立连接。示例性的，第二区域可以是第一接入网设备离开终端设备后在运行轨道上移动到的第一个有NTN网关覆盖的区域，也可以是运行轨道上即将进入终端设备位置的有NTN网关覆盖的区域，此处不做限定。
需要说明的是，终端设备能够收到来自第一接入网设备的第一指示信息，说明该第一接入网设备当前未与核心网设备成功建立连接。本申请中，第一接入网设备在第一区域保存来自终端设备的信令，待该第一接入网设备移到第二区域到再向核心网设备转发来自终端设备的信令，将这种信令传输方式称为 存储转发(store and forward)模式。可以将收到第一指示信息的终端设备称为处于store and forward模式的终端，也可以称该终端设备所在的地理区域是store and forward模式的地理区域。
可选的，终端设备的AS读取到系统消息里的第一指示信息之后，该终端设备的AS将通知终端设备的NAS生效终端设备的第一NAS定时器或延迟启动终端设备的第二NAS定时器。
本步骤中，第二NAS定时器是接入网设备(例如，第一接入网设备)能够与核心网设备建立连接时终端设备使用的NAS定时器；也可以理解为，第二NAS定时器是终端设备未从接入网设备(例如，第一接入网设备)接收到第一指示信息时终端设备使用的NAS定时器；也可以理解为，第二NAS定时器是终端设备未处于store and forward模式时终端设备使用的NAS定时器；也可以理解为，第二NAS定时器是终端设备未位于store and forward模式的地理区域时终端设备使用的NAS定时器。第二NAS定时器是地面网络TN中当前协议(例如，针对5G NAS定时器的TS 24.501)已经定义的传统NAS层的定时器。该第二NAS定时器不具体指代单一定时器，针对不同类型的NAS消息，可以有不同的第二NAS定时器。示例性的，当NAS消息为注册请求(Registration Rquest)消息时，该第二NAS定时器为T3510。当终端设备发送注册请求消息时，该终端设备启动T3510；当终端设备收到注册拒绝(Registeration Reject)消息或注册接收(Registeration Accept)消息时，终端设备停止T3510。此外，该第二定时器还可以是协议定义的其他的终端设备使用的NAS定时器，例如T3511等定时器，此处不再一一列举。
本步骤中，第一NAS定时器是接入网设备(例如，第一接入网设备)不能与核心网设备建立连接时终端设备使用的NAS定时器；也可以理解为，第一NAS定时器是终端设备从第一接入网设备接收到第一指示信息时终端设备使用的NAS定时器；也可以理解为，第一NAS定时器是终端设备处于store and forward模式时终端设备使用的NAS定时器；也可以理解为，第一NAS定时器是终端设备位于store and forward模式的地理区域时终端设备使用的NAS定时器。第一NAS定时器不具体指代单一定时器，根据不同类型的NAS消息，可以有不同的第一NAS定时器。示例性的，当NAS消息为注册请求(Registration Rquest)消息时，该第一NAS定时器为注册请求消息对应的NAS定时器。当终端设备发送注册请求时，该终端设备启动该第一NAS定时器；当终端设备收到注册拒绝(Registeration Reject)消息或注册接收(Registeration Accept)消息时，终端设备停止该第一NAS定时器。
需要说明的是，第一NAS定时器可以是新定义的独立于第二NAS定时器的定时器。可选的，第一NAS定时器的时长大于第二NAS定时器的时长。例如，第一NAS定时器可以是基于第二NAS定时器再新增一个时长偏置而获得的定时器。以NAS消息为注册请求(Registration Rquest)消息为例，该注册请求消息对应的第二NAS定时器为T3510，该注册请求消息对应的第一NAS定时器可以是新定义的专用于非地面网络NTN的T3510-new。例如，终端设备在TN通信过程中使用T3510，在NTN通信过程中使用T3510-new。若协议中第二NAS定时器T3510的默认时长为15s，则第一NAS定时器T3510-new可以基于第二NAS定时器T3510增加一个时长偏置(例如，5s)而获得的时长为20s的NAS定时器。
需要说明的是，终端设备的NAS生效第一NAS定时器，指终端设备在启动NAS定时器时，启动的是第一NAS定时器，而不是启动传统技术中的NAS定时器(例如，第二NAS定时器)。例如，终端设备在发送了上行NAS消息时启动第一NAS定时器，而不是按照传统技术的方案在送了上行NAS消息时启动第二NAS定时器。
还需要说明的是，终端设备延迟启动第二NAS定时器，指终端设备在传统技术中应当启动NAS定时器的时刻不立即启动第二NAS定时器，而是延迟一段时长(例如，第一时长)后再启动第二NAS定时器。例如，终端设备在发送了上行NAS消息时在第一时长之后再启动第二NAS定时器，而不是按照传统技术的方案在送了上行NAS消息时立即启动第二NAS定时器。
可选的，第一接入网设备可以向终端设备发送第一时间信息，相应地，终端设备还可以接收来自该第一接入网设备的第一时间信息。第一时间信息可以携带在系统消息中，也可以基于终端设备的专有信令下发给终端设备，具体携带形式不做限定。第一时间信息用于终端设备确定前述第一NAS定时器的时长或者前述第一时长。终端设备可以根据约定的算法将第一时间信息转换为第一NAS定时器的时长或者前述第一时长。示例性的，第一时间信息可以是第一接入网设备下次到达该终端设备所在地理区域的时间，也可以是第一接入网设备绕轨道一圈的时长，还可以是星历信息，此处不做限定。其中，星历 信息(也被称为星历数据(ephemeris data)或星历表)用于指示运行的卫星的运行轨道信息。终端设备根据该运行轨道信息可以确定卫星的位置。示例性的，星历信息可以是通过两行轨道数据(two-line orbital element，TLE)格式来表示的。
可选的，若第一接入网设备在第一小区广播第一指示信息，则第一接入网设备还可以在第一小区广播第一小区的小区标识信息，相应地，终端设备还可以在第一小区接收来自该第一接入网设备第一小区的小区标识信息。其中，第一接入网设备的标识信息可以是卫星标识。其中，第一小区的小区标识信息可以是全球小区标识(cell global identifier，CGI)，该CGI与第一接入网设备绑定，而不与地面区域绑定。
步骤302，终端设备与第一接入网设备建立连接。
示例性的，终端设备与位于第一区域的第一接入网设备建立连接。
以基于四步的随机接入流程为例，终端设备通过如下步骤与第一接入网设备建立连接：
步骤302.1终端设备向第一接入网设备发送消息1(message 1，Msg1)。
其中，Msg1包含随机接入前导(random access preamble，RAP)，RAP的主要作用是告诉第一接入网设备有一个随机接入请求，并使得第一接入网设备能够估计其余终端设备之间的传输时延，以便第一接入网设备可以校准上行定时提前量(uplink timing advance)并将校准信息通过时间提前命令告知终端设备。
步骤302.2，第一接入网设备向终端设备发送消息2(message 2，Msg2)。
其中，该Msg2包含随机接入响应(random access response，RAR)，RAR中包含第一接入网设备为终端设备分配的临时的小区无线网络临时标识(temporary cell radio network temporary identifier，T-CRNTI)和上行定时提前量。
步骤302.3，终端设备向第一接入网设备发送消息3(message 3，Msg3)。
其中，在初始网络接入时该Msg3为RRC建立请求(RRC Setup Requst)消息，包含终端设备的标识信息(例如，临时移动用户标识符(temporary mobile subscription identifier，TMSI)或者随机数)以及RRC建立原因值。
步骤302.4，第一接入网设备向终端设备发送消息4(message 4，Msg4)。
在初始接入时，第一接入网设备向终端设备发送的Msg4可以包含竞争解决消息和RRC建立(RRC Setup)消息。其中，RRC Setup里配置了小区组配置(cell group configuration)(TS 38.331，section5.3.5.5)和无线承载配置(radio bearer configuration)(TS 38.331section5.3.5.6)，或者无线资源专用配置(dedicated raido bearer configuration)(TS 36.331section5.3.3)，并将小区无线网络临时标识C-RNTI设置为步骤302.2里的T-CRNTI。
可选的，该Msg4还包括第一标识信息，第一标识信息用于在第一接入网设备中唯一标识该终端设备。也可以理解为，第一接入网设备在运行轨道上的不同位置时都可以通过第一标识信息唯一标识该终端设备。也就是说，无论第一接入网设备移动到轨道的哪个位置，接入了多少终端设备，该第一标识信息均能够唯一标识前述终端设备。
可选的，第一标识信息的长度大于小区无线网络临时标识C-RNTI的长度。
需要说明的是，随着第一接入网设备的移动可能存在较多终端设备在不同时刻接入第一接入网设备，导致仅凭C-RNTI不足以唯一标识一个终端设备。因此，第一接入网设备除了为终端设备分配C-RNTI之外，还可以为终端设备分配第一标识信息，以使得能够在第一接入网设备唯一标识该终端设备，进而有利于第一接入网设备在下一次到达终端设备所在地理区域时能够通过第一标识信息查找到该终端设备的上下文。
步骤302.5，终端设备向第一接入网设备发送消息5(message 5，Msg5)。
其中，该Msg5为RRC建立完成(RRC Setup Complete)消息，该Msg5携带上行NAS消息(例如，初始接入时的上行NAS消息为注册请求(Register Request)消息)。终端设备在发送的Msg5里携带上行NAS消息时，终端设备基于上行NAS消息的类型立即启动第一NAS定时器，或者，在第一时长之后启动第二NAS定时器。关于第一NAS定时器和第二NAS定时器的介绍请参阅前文步骤301中的相 关描述，此处不予赘述。第一NAS定时器超时或第二NAS定时器超时后，保持与第二NAS定时器超时后的处理方式相同，5G系统的NAS定时器超时后的方式详细见TS 24.501，section10.2。
可选的，终端设备在发送Msg5之后，或者，第一NAS定时器或第二NAS定时器运行期间，终端设备将处于一种新的RRC状态，该新的RRC状态区别于传统技术中的RRC空闲态、RRC非激活态和RRC连接态。为便于介绍，后文称该新的RRC状态为第一状态，应理解，“第一状态”仅是为便于介绍而列举的称谓示例，本申请不限定该RRC状态的称谓。
在一种实施方式中，在该第一状态下，终端设备保持终端设备的上下文(例如，步骤303存储的终端设备的上下文)，终端设备可以执行小区测量、执行小区下行同步以及读取系统消息，但不会触发无线连接失败(radio link failure，RLF)流程，不会触发RRC重建流程。进一步的，进入第一状态的终端可以在第一接入网设备停止服务后暂时先关闭物理层搜索和检测信号等功能，等到第一接入网设备再次到达该终端设备所在的地理区域时或者达到之前(例如，终端设备可以通过第一时间信息确定第一接入网设备何时到达)，该终端设备再开启物理层搜索和检测信号等功能。
在另一种实施方式中，在该第一状态下，终端设备保持终端设备的上下文(例如，步骤303存储的终端设备的上下文)，在第一接入网设备再次到达能覆该终端设备的区域之前，终端设备不执行小区测量、小区下行同步以及读取系统消息，在第一接入网设备再次到达能覆该终端设备的区域时或之后，终端设备执行小区测量、小区下行同步以及读取系统消息)，但不会触发无线连接失败(radio link failure，RLF)流程，不会触发RRC重建流程。本实施方式中，当终端设备进入第一状态时，该终端设备可以先关闭物理层搜索和检测信号等功能，等到第一接入网设备再次到达该终端设备所在的地理区域时或者达到之前(例如，终端设备可以通过第一时间信息确定第一接入网设备何时到达)，该终端设备再开启物理层搜索和检测信号等功能。
由于，进入第一状态的终端设备不会触发无线连接失败RLF流程，不会触发RRC重建流程，有利于终端设备复用已有的RRC连接相关的配置，节省用于重建RRC连接的信令开销。此外，由于，终端设备在第一状态下可以暂时关闭物理层搜索和检测信号等功能，因此，有利于节省终端设备的能耗。
可选的，当终端设备再次与第一接入网设备发起建立连接时，该终端设备退出第一状态。
步骤303，终端设备根据该第一指示信息存储终端设备的上下文。
其中，终端设备的上下文包括终端设备接入第一接入网设备时使用的与接入层AS相关的信息，也称为终端设备的AS上下文。其中，终端设备的AS上下文包括服务小区的小区标识。例如，若终端设备接入第一接入网设备的第一小区，则该服务小区的小区标识为第一小区的小区标识。终端设备的AS上下文还包括终端设备的标识信息。例如，终端设备的标识信息可以是第一接入网设备为终端设备配置的C-RNTI。又例如，在第一接入网设备在接入过程中为终端设备配置了第一标识信息的情况下，终端设备的标识信息还可以是第一标识信息。终端设备的AS上下文还包括第一接入网设备为终端设备配置的时频资源相关的信息(例如，小区资源配置信息(cell group configuration))以及第一接入网设备为终端设备配置的承载相关的信息(例如，无线承载配置(radio bear configuration)中的SRB0、SRB1相关的信息等)。
可选的，终端设备的上下文还包括终端设备的非接入层(non-access stratum，NAS)相关的信息，也称为终端设备的NAS上下文。例如，终端设备已发送的上行NAS消息，终端设备已经启动的相关NAS定时器，已选择的PLMN标识(selected PLMN-Identity)、已注册的核心网设备相关的信息(例如，registered AMF)等。
应注意，终端设备可以在执行步骤302之后执行步骤303，也可以在执行步骤302的过程中执行步骤303，此处不做限定。
示例性的，从终端设备开始接入第一接入网设备时，该终端设备可以持续记录终端设备的上下文，终端设备成功接入第一接入网设备之后，该终端设备也会持续更新终端设备的上下文，直至第一接入网设备停止为终端设备提供服务。例如，终端设备在第一接入网设备发起Msg1时记录以下至少一项：第一小区的小区标识信息、公共陆地移动网(public land mobile network，PLMN)以及TAC；终端设备在发送Msg3之后在终端设备的上下文中记录终端设备的标识信息(例如，TC-RNTI)以及RRC建立原因 值。又例如，终端设备在收到Msg4之后在终端设备的上下文中记录SRB1相关的信息、C-RNTI和/或第一标识信息。又例如，终端设备在发送Msg5之后在终端设备的上下文中记录终端设备已发送的上行NAS消息或者记录已发送的上行NAS的指示信息，以及Msg5中携带的已选择的PLMN标识、已注册的核心网设备相关的信息等。
本步骤中，由于终端设备能够基于收到的来自第一接入网设备的第一指示信息确定该第一接入网设备当前不能与核心网设备成功建立连接，因此，当该终端设备接入第一接入网设备时，该终端设备将从开始接入第一接入网设备时便持续记录终端设备的上下文，直至第一接入网设备停止为终端设备提供服务。在第一接入网设备停止为终端设备提供服务后，终端设备保存该上下文直到在第一接入网重新发起接入后，终端设备根据第一接入网设备的配置更新上下文；当终端设备因为接入第一接入网设备失败时重新选择其他网络并发起接入时，终端设备删除前述上下文。因此，当该第一接入网设备停止为终端设备提供服务时，该终端设备的上下文中记载有终端设备接入第一接入网设备时使用的与接入相关的信息(例如，第一接入网设备配置的C-RNTI、第一标识信息以及SRB1相关的信息等)。有利于当第一接入网设备再次移动至终端设备所在的地理区域时，终端设备能够快速接入第一接入网设备。
步骤304，第一接入网设备存储终端设备的上下文。
应注意，步骤303与步骤304无明确的时间先后顺序的限定。例如，终端设备先执行步骤303，再由第一接入网设备执行步骤304。又例如，第一接入网设备先执行步骤304，再由终端设备执行步骤303。又例如，终端设备执行步骤303的同时，第一接入网设备执行步骤304。
本步骤中，终端设备的上下文包括终端设备接入第一接入网设备时使用的与接入层AS相关的信息，也称为终端设备的AS上下文。其中，终端设备的AS上下文包括服务小区的小区标识、终端设备的标识信息(包括第一标识信息和/或C-RNTI)、第一接入网设备为终端设备配置的时频资源相关的信息(包括小区资源配置信息(cell group configuration)和无线承载配置(radio bear configuration))，具体请参阅前文步骤303中的相关描述，此处不予赘述。可选的，终端设备的AS上下文还包括终端设备接入第一接入网设备时的地理区域信息和/或终端设备接入第一接入网设备的时间信息。其中，终端设备的地理区域信息用于指示该终端设备所在的地理区域(例如，终端设备接入第一接入网设备时该终端设备所在的地理区域)。该地理区域可以是由经纬度表示的物理区域，也可以是TAC区域(例如，TAC指示的区域，或者，PLMN和TAC指示的区域)。
终端设备的上下文还包括与NAS相关的信息，也称为终端设备的NAS上下文。例如，终端设备已发送的上行NAS消息，终端设备已经启动的相关NAS定时器，已选择的PLMN标识(selected PLMN-Identity)、已注册的核心网设备相关的信息(例如，registered AMF)等。
示例性的，第一接入网设备在收到来自终端设备的Msg3之后，第一接入网设备建立终端设备的上下文，并记录与接入层AS相关的信息，直至该第一接入网设备停止为该终端设备提供服务。例如，第一接入网设备获取Msg3终端设备的标识信息(例如，TMSI或者随机数)以及RRC建立原因值，并在终端设备的上下文中记录终端设备的标识信息(例如，TMSI或者随机数)以及RRC建立原因值。然后，第一接入网设备进行SRB1资源的准入和资源分配，并在终端设备的上下文中记录SRB1相关的信息。又例如，第一接入网设备通过Msg4为终端设备分配C-RNTI和/或第一标识信息之后，第一接入网设备在终端设备的上下文中记录C-RNTI和/或第一标识信息。又例如，第一接入网设备在终端设备接入之后记录终端设备的地理区域信息和/或终端设备接入第一接入网设备的时间信息。
步骤305，第一接入网设备从第一区域移动至第二区域。
由于，第一区域包括终端设备所在的地理区域，当第一接入网设备离开第一区域(即第一接入网设备离开终端设备所在的地理区域)时，该第一接入网设备停止为终端设备提供服务。此时，终端设备仍旧处于第一状态。当第一接入网设备到达第二区域时，第一接入网设备在第二区域能够与核心网设备成功建立连接(例如，S1/NG连接)(或者，第一接入网设备在第二区域能够与核心网设备交互信息)，然后，该第一接入网设备与核心网设备交互终端设备的NAS信令。具体地，该第一接入网设备和核心网设备将依次执行步骤306和步骤307。
步骤306，第一接入网设备向核心网设备发送上行NAS消息。
相应地，核心网设备从第一接入网设备接收上行NAS消息。
本步骤中，第一接入网设备从终端设备接收到的第一条上行NAS消息可以携带于初始消息(Initial UE Message)中转发给核心网。例如，第一接入网设备向核心网设备发送包含注册请求(Register Rquest)消息的Initial UE Message，相应地，核心网设备从第一接入网设备接收终端设备的初始消息以获得上行NAS消息。
可选的，第一接入网设备向核心网设备发送第四指示信息，该第四指示信息用于指示该终端设备是在该第一接入网设备不能与该核心网设备交互信息时接入到该第一接入网设备。示例性的，第四指示信息可以指示终端设备在核心网和接入网设备之间动态接入或核心网和接入网设备之间执行动态连接(关于动态连接的解释请参阅后文步骤701中的相关介绍)。例如，第四指示信息为指示终端设备处于store and forward模式的信息(终端设备处于store and forward模式也可以称为终端设备通过store and forward模式的接入网设备接入)。示例性的，第四指示信息也可以采用指示终端设备所在的地理区域的模式的信息实现，例如，第四指示信息为指示终端设备所在的地理区域是store and forward模式的地理区域。
可选的，核心网设备在收到第四指示信息之后，基于第四指示信息用于生效核心网设备的第一NAS定时器或延迟启动核心网设备的第二NAS定时器。
本步骤中，第二NAS定时器是接入网设备(例如，第一接入网设备)能够与核心网设备建立连接时核心网设备使用的NAS定时器；也可以理解为，第二NAS定时器是核心网设备从接入网设备未接收到第四指示信息时核心网设备使用的NAS定时器；也可以理解为，第二NAS定时器是终端设备未处于store and forward模式时核心网设备使用的NAS定时器；也可以理解为，第二NAS定时器是终端设备未位于store and forward模式的地理区域时核心网设备使用的NAS定时器。第二NAS定时器是地面网络TN中当前协议(例如，针对5G NAS定时器的TS24.501)已经定义的传统NAS层的定时器。该第二NAS定时器不具体指代单一定时器，针对不同类型的NAS消息，可以有不同的第二NAS定时器。示例性的，当NAS消息为鉴权请求(Authentication Rquest)消息时，该第二NAS定时器为T3460。当核心网设备发送鉴权请求消息时，该核心网设备启动T3460；当核心网设备收到鉴权响应(Authentication Response)消息时，核心网设备停止T3460。示例性的，当NAS消息为身份请求(Identity Rquest)消息时，该第二NAS定时器为T3470。当核心网设备发送身份请求消息时，该核心网设备启动T3470；当核心网设备收到身份响应(Identity Response)消息时，核心网设备停止T3470。此外，该第二定时器还可以是协议定义的其他的核心网设备使用的NAS定时器，此处不再一一列举。
本步骤中，第一NAS定时器是接入网设备(例如，第一接入网设备)不能与核心网设备建立连接时核心网设备使用的NAS定时器；也可以理解为，第一NAS定时器是核心网设备从第一接入网设备接收到第四指示信息时使用的NAS定时器；也可以理解为，第一NAS定时器是终端设备处于store and forward模式时核心网设备使用的NAS定时器；也可以理解为，第一NAS定时器是终端设备位于store and forward模式的地理区域时核心网设备使用的NAS定时器。第一NAS定时器不具体指代单一定时器，根据不同类型的NAS消息，可以有不同的第一NAS定时器。示例性的，当NAS消息为鉴权请求(Authentication Rquest)消息时，该第一NAS定时器为鉴权请求消息对应的NAS定时器。当核心网设备发送鉴权请求时，该核心网设备启动该第一NAS定时器；当核心网设备收到鉴权响应(Authentication Response)消息时，核心网设备停止该第一NAS定时器。
需要说明的是，第一NAS定时器可以是新定义的独立于第二NAS定时器的定时器。可选的，第一NAS定时器的时长大于第二NAS定时器的时长。例如，第一NAS定时器可以是基于第二NAS定时器再新增一个时长偏置而获得的定时器。以NAS消息为鉴权请求(Authentication Rquest)消息为例，该鉴权请求消息对应的第二NAS定时器为T3460，该鉴权请求消息对应的第一NAS定时器可以是新定义的专用于非地面网络NTN的T3460-new。例如，核心网设备在TN通信过程中使用T3460，在NTN通信过程中使用T3460-new。若协议中第二NAS定时器T3460的默认时长为10s，则第一NAS定时器T3460-new可以基于第二NAS定时器T3460增加一个时长偏置(例如，5s)而获得的时长为15s的NAS定时器。
需要说明的是，核心网设备生效第一NAS定时器，指核心网设备在启动NAS定时器时，启动的是第一NAS定时器，而不是启动传统技术中的NAS定时器(例如，第二NAS定时器)。例如，核心网 设备在发送了下行NAS消息时启动第一NAS定时器，而不是按照传统技术的方案在送了下行NAS消息时启动第二NAS定时器。
还需要说明的是，核心网设备延迟启动第二NAS定时器，指核心网设备在传统技术中应当启动NAS定时器的时刻不立即启动第二NAS定时器，而是延迟一段时长(例如，第一时长)后再启动第二NAS定时器。例如，核心网设备在发送了下行NAS消息时在第一时长之后再启动第二NAS定时器，而不是按照传统技术的方案在送了下行NAS消息时立即启动第二NAS定时器。
可选的，第一接入网设备还可以向核心网设备发送第一时间信息，相应地，核心网设备还可以接收来自该第一接入网设备的第一时间信息。关于第一时间信息的介绍请参阅前文步骤301中的相关描述，此处不予赘述。
需要说明的是，第四指示信息和/或第一时间信息可以携带于终端设备的初始消息中发送给核心网设备，也可以携带在其他消息中发送给核心网设备，此处不做限定。
步骤307，核心网设备向第一接入网设备发送下行NAS消息。
相应地，第一接入网设备从核心网设备接收下行NAS消息。
当核心网设备向第一接入网设备发送下行NAS消息时，核心网设备立即启动第一NAS定时器，或者，在第一时长之后启动第二NAS定时器。
需要说明的是，核心网设备可以向当前位于第二区域的第一接入网设备发送多条下行NAS消息。例如，核心网设备向第一接入网设备发送用于鉴权的下行NAS消息、用于加密的下行NAS消息和用于注册的下行NAS消息。核心网设备也可以向当前位于第二区域的第一接入网设备发送一条下行NAS消息，待该第一接入网设备再次移动至该第二区域时再向第一接入网设备发送另一条下行NAS消息。例如，核心网设备先向当前位于第二区域的第一接入网设备发送用于鉴权的下行NAS消息，待该第一接入网设备再次移动至该第二区域时再向第一接入网设备发送用于NAS加密的下行NAS消息，待该第一接入网设备再次移动至该第二区域时再向第一接入网设备发送注册接受的下行NAS消息。
步骤308，第一接入网设备存储终端设备的下行NAS消息。
第一接入网设备收到来自核心网设备的下行NAS消息之后，该第一接入网设备将该终端设备的下行NAS消息与终端设备的上下文对应存储。由于，该第一接入网设备此时还未与终端设备建立连接，因此，该第一接入网设备不会立即下发下行NAS消息。
步骤309，第一接入网设备从第二区域移动至第一区域。
由于，该终端设备所在的地理区域位于所述第一区域中，在第一接入网设备移动至第一区域之后，第一接入网设备将通过步骤310a或步骤310b触发终端设备执行步骤311，即第一接入网设备将通过步骤310a或步骤310b触发终端设备发起接入该第一接入网设备。
需要说明的是，步骤309中的第一区域和步骤301至步骤305中的第一区域可能是不同的物理区域，也可能是相同的物理区域。步骤309中的第一区域和步骤301至步骤305中的第一区域都包括了终端设备所在的物理区域。
步骤310a，第一接入网设备广播第一小区的小区标识信息。
相应地，终端设备从第一接入网设备接收第一小区的小区标识信息。
可选的，第一小区的小区标识信息可以携带于系统消息中。示例性的，第一接入网设备将在系统消息中广播该第一接入网设备的各个小区的小区标识信息，该终端设备可以接收前述包含各个小区的小区标识信息的系统消息。若终端设备在系统消息中收到的小区标识信息，与终端设备的上下文中存储的第一小区的小区标识信息相同，则该终端设备触发接入该小区。
由于，终端设备的上下文存储的第一小区的小区标识信息，表示该第一小区是该终端设备曾经接入过的小区(例如，第一接入网设备曾经为终端设备提供服务时该终端设备接入的小区)，该终端设备的上下文可能记录有该终端设备接入该第一小区的相关配置信息，因此，该终端设备将有较高的几率基于该终端设备的上下文接入该第一小区，有利于提高终端设备接入第一接入网设备的效率。
步骤310b，第一接入网设备广播第二指示信息。
相应地，终端设备从第一接入网设备接收第二指示信息。
其中，第二指示信息用于指示该终端设备发起接入，也可以理解为，该第二指示信息用于指示终端设备触发接入到第一接入网设备。示例性的，该第二指示信息为物理下行控制信道命令(physical downlink control channel order，PDCCH order)。当该终端设备接收来自该第一接入网设备的第二指示信息之后，该终端设备基于第二指示信息触发接入该第一接入网设备。
可选的，该终端设备基于第二指示信息触发接入该第一接入网设备的第一小区。例如，第一接入网设备在第一小区广播第二指示信息，该终端设备在第一小区收到第二指示信息，则该终端设备触发接入该第一小区。其中，第一小区是终端设备的上下文中存储的小区。
需要说明的是，第一接入网设备在哪个小区广播第二指示信息，该终端设备在哪个小区收到第二指示信息便触发接入哪个小区。因此，终端设备前后两次可能接入第一接入网设备的同一个小区，也可能接入第一接入网设备的不同小区。
步骤311，终端设备基于终端设备的上下文与第一接入网设备建立连接。
由于，终端设备存储有终端设备的上下文，第一接入网设备也存储有终端设备的上下文，并且，终端设备的上下文包含终端设备的AS配置信息，因此，终端设备与第一接入网设备仅需要进行上行同步便可以复用上下文中的AS配置信息建立连接。示例性的，终端设备可以先与第一接入网设备进行上下行同步，之后继续使用终端设备的上下文中的配置与第一接入网设备进行进一步的通信，从而第一接入网设备可以基于终端设备的上下文中的配置的时频资源和/或无线承载资源与第一接入网设备进行通信，而无需第一接入网设备重新执行RRC初始建立。
示例性的，终端设备通过如下步骤与第一接入网设备建立连接：
步骤311.1终端设备向第一接入网设备发送Msg1。
其中，Msg1包含随机接入前导(random access preamble，RAP)，RAP可能是PDCCH order中携带的，也可能是系统消息中广播的。若RAP携带于PDCCH Order中，则该RAP是第一接入网设备分配给该终端设备的，该RAP可以用于非竞争随机接入；若RAP是在系统消息中广播的随机接入配置中，则终端设备随机选择随机接入前导码，终端设备可以做基于竞争的随机接入。
步骤311.2，第一接入网设备向终端设备发送Msg2。
其中，该Msg2包含随机接入响应RAR、第一接入网设备为终端设备分配的临时的小区无线网络临时标识T-CRNTI以及上行定时提前量。
步骤312，终端设备向第一接入网设备发送终端设备的标识信息。
其中，终端设备的标识信息是终端设备的上下文中存储的C-RNTI和/或第一标识信息。
在一种可能的实施方式中，继步骤311.2之后，在Msg2的上行授权中，终端设备可以向第一接入网设备发送C-RNTI MAC CE，其中C-RNTI为终端设备初次接入第一接入网设备时分配的C-RNTI，并保存在终端设备上下中。
在一种可能的实施方式中，第一接入网设备在步骤302中为终端设备配置了第一标识信息，终端设备的上下文中存储有第一标识信息，则终端设备向第一接入网设备发送第一标识信息。
步骤313，第一接入网设备基于终端设备的标识信息确定终端设备的上下文。
当第一接入网设备收到的终端设备的标识信息的实现方式不同时，第一接入网设备确定终端设备的上下文的方式不同。下面分别进行介绍：
在一种可能的实施方式中，第一接入网设备从终端设备接收的是第一标识信息，则该第一接入网设备基于第一标识信息确定该终端设备的上下文。由于，第一标识信息能够在第一接入网设备唯一标识该终端设备，因此，第一接入网设备基于第一标识信息能够精准查找该终端设备的上下文。
在另一种可能的实施方式中，第一接入网设备从终端设备接收的是小区无线网络临时标识。当第一接入网设备存储的终端设备的上下文包括该终端设备接入第一接入网设备时的地理区域信息和/或终端设备接入该第一接入网设备的时间信息时，该第一接入网设备基于该终端设备接入第一接入网络设备时的地理区域信息和/或终端设备接入该第一接入网设备的时间信息，以及小区无线网络临时标识确定该终端设备的上下文。
在本实施方式的一种可能的示例中，第一接入网设备存储的终端设备的上下文包括该终端设备接入 第一接入网络设备时的地理区域信息，该第一接入网设备基于该终端设备接入第一接入网络设备时的地理区域信息和小区无线网络临时标识确定该终端设备的上下文。
在本实施方式的另一种可能的示例中，第一接入网设备存储的终端设备的上下文包括终端设备接入该第一接入网设备的时间信息，该第一接入网设备基于终端设备接入该第一接入网设备的时间信息和小区无线网络临时标识确定该终端设备的上下文。
在本实施方式的另一种可能的示例中，第一接入网设备存储的终端设备的上下文包括终端设备接入第一接入网络设备时的地理区域信息和终端设备接入该第一接入网设备的时间信息，该第一接入网设备基于终端设备的地理区域信息、终端设备接入该第一接入网设备的时间信息和小区无线网络临时标识确定该终端设备的上下文。
本实施例中，第一接入网设备基于前述任意一种实施方式确定终端设备的上下文之后，该第一接入网设备与终端设备可以继续交互NAS消息。
步骤314，第一接入网设备基于终端设备的上下文确定终端设备的下行NAS消息。
需要说明的是，第一接入网设备可能基于终端设备的上下文确定了多条该终端设备的下行NAS消息，也可能基于终端设备的上下文仅确定一条该终端设备的下行NAS消息。可选的，第一接入网设备基于终端设备的上下文确定的终端设备的下行NAS消息的数量与第一接入网设备在第二区域从核心网设备接收的下行NAS消息的数量相同。
步骤315，第一接入网设备向终端设备转发下行NAS消息。
可选的，第一接入网设备还将更新终端设备的上下文中与NAS相关的信息(即终端设备的NAS上下文)。例如，第一接入网设备将转发给终端设备的下行NAS消息存储至终端设备的上下文中，或者，第一接入网设备存储一个指示信息以指示该第一接入网设备向终端设备转发了哪个下行NAS消息。
步骤316，终端设备向第一接入网设备发送上行NAS消息。
本步骤中，该上行NAS消息可以是与步骤315中的下行NAS消息对应的消息。示例性的，该上行NAS消息是该下行NAS消息的响应消息。例如，若该下行NAS消息为鉴权请求(Authentication Rquest)消息，则该上行NAS消息可以是鉴权响应(Authentication Response)消息。又例如，若该下行NAS消息为安全模式命令(Security Mode Command)消息，则该上行NAS消息可以是安全模式完成(Security Mode Complete)消息。又例如，若该下行NAS消息为注册接收(Register Accept)消息，则该上行NAS消息可以是注册完成(Register Complete)消息。
此外，该上行NAS消息还可以是终端设备NAS层触发的流程消息。例如，初始接入完成后，需要建立分组数据单元(packet data unit，PDU)承载时，该上行NAS消息是承载建立请求(PDU session establishment request)消息。
步骤317，第一接入网设备存储终端设备的上行NAS消息。
在一种可能的实施方式中，第一接入网设备将接收到的上行NAS消息存储在终端设备上下文中。
在另一种可能的实施方式中，第一接入网设备将接收到的上行NAS消息与终端设备上下文建立映射关系，以使得第一接入网设备根据终端设备的上下文可以查询到需要透传给核心网设备的上行NAS消息。
步骤318，第一接入网设备从第一区域移动至第二区域。
第一接入网设备移动至第二区域之后，该第一接入网设备与核心网设备成功建立连接。
需要说明的是，步骤318中的第二区域和步骤305至步骤309中的第二区域可能是不同的物理区域，也可能是相同的物理区域。第一接入网设备在步骤318中的第二区域和步骤305至步骤309中的第二区域均能与核心网设备交互信息。例如，步骤318中的第二区域和步骤305至步骤309中的第二区域均存在至少一个能够使第一接入网设备与核心网设备建立连接并进行信息交互的NTN网关。
步骤319，第一接入网设备向核心网设备发送上行NAS消息。
需要说明的是，当第一接入网设备确定该核心网设备是终端设备的上下文中保存的核心网设备时，第一接入网设备向核心网设备转发上行NAS消息。
需要说明的是，若NAS信令还未交互完，则该核心网设备将通过第一接入网设备继续与终端设备 交互NAS信令。示例性的，该核心网设备还会向第一接入网设备发送下一条下行NAS消息，第一接入网设备存储收到的下行NAS消息。待第一接入网设备移动至第一区域之后，第一接入网设备与终端设备建立连接，并向终端设备发送存储的下行NAS消息，以及从终端设备接收终端设备回复上行NAS消息，并存储该上行NAS消息。待第一接入网设备移动至第二区域之后，第一接入网设备与核心网设备建立连接，并向核心网设备发送存储的上行NAS消息。具体过程与步骤307至步骤319类似，此处不予赘述。
为便于理解，以图4A和图4B为例介绍本实施例的方案。如图4A所示，当第一接入网设备位于第一区域(例如，没有NTN网关覆盖的区域)时，该第一接入网设备通过第一指示信息知会终端设备该第一接入网设备未与核心网设备建立连接。待该终端设备接入该第一接入网设备之后，终端设备和第一接入网设备均能够存储终端设备的上下文，并且，第一接入网设备还会存储从终端设备接收的初始NAS消息(即携带在Msg5中的上行NAS消息，例如，注册请求消息)。当第一接入网设备停止为终端设备提供服务之后，第一接入网设备沿着运行轨道从第一区域移动至第二区域(例如，有NTN网关覆盖的区域)。位于第二区域的第一接入网设备与核心网设备建立连接，并通过NTN网关向核心网设备发送初始NAS消息，以及，通过NTN网关从核心网设备接收下行NAS消息1。如图4B所示，当第一接入网设备再次移动至第一区域(包括该终端设备所在的地理区域)时，第一接入网设备基于存储终端设备的上下文快速与终端设备建立连接。在连接建立后，第一接入网设备向终端设备发送下行NAS消息1，终端设备向第一接入网设备回复响应于下行NAS消息1的上行NAS消息1。当第一接入网设备停止为终端设备提供服务之后，第一接入网设备再次从第一区域移动至第二区域(例如，有NTN网关覆盖的区域)。位于第二区域的第一接入网设备再次与核心网设备建立连接，并通过NTN网关向核心网设备发送上行NAS消息1。可选的，若还存在需要交互的NAS信令(例如，下行NAS消息2)，则第一接入网设备可以按照类似的方式继续交互NAS信令。通过多次NAS信令交互，终端设备和核心网之间NAS注册成功，进而该终端设备可以获得网络服务。
本实施例中，由于，终端设备和第一接入网设备均能够存储终端设备的上下文以保留终端设备接入第一接入网设备时使用的配置信息(例如，时频资源、无线承载等配置信息)，当第一接入网设备再次到达终端设备所在的地理区域时，终端设备与第一接入网设备能够基于终端设备的上下文快速完成上下行同步并继续交互NAS信令，而不需要终端设备在第一接入网设备重新进行RRC的初始建立。因此，不仅有利于节省与第一接入网设备建连的信令开销，有利于提高终端设备接入第一接入网设备的效率。由于，第一接入网设备每次到达终端设备所在的地理区域时，能够快速接纳终端设备并继续与终端设备交互NAS信令，因此，有利于通过第一接入网设备快速交互完NAS信令而完成终端设备在核心网侧的注册流程，进而使得位于没有NTN网关覆盖的区域的终端设备也能够获得网络服务。
下面将结合图5对本申请提出的通信方法进行进一步介绍。本实施例中，第二接入网设备与第一接入网设备为不同的接入网设备。例如，第一接入网设备和第二接入网设备可以在不同时刻为终端设备提供服务。具体地，第一接入网设备、第二接入网设备、终端设备和核心网设备将执行如下步骤。
步骤501，第一接入网设备广播第一指示信息。
相应地，终端设备接收第一指示信息。
步骤502，终端设备与第一接入网设备建立连接。
可选的，终端设备在发送Msg5之后，或者，第一NAS定时器或第二NAS定时器运行期间，终端设备将处于一种新的RRC状态，该新的RRC状态区别于传统技术中的RRC空闲态、RRC非激活态和RRC连接态。为便于介绍，后文称该新的RRC状态为第二状态，应理解，“第二状态”仅是为便于介绍而列举的称谓示例，本申请不限定该RRC状态的称谓。
在一种实施方式中，在该第二状态下，终端设备保持终端设备的上下文(例如，步骤503存储的终端设备的上下文)，终端设备可以执行小区测量、执行小区下行同步以及读取系统消息，但不会触发无线连接失败(radio link failure，RLF)流程，不会触发RRC重建流程。进一步的，进入第二状态的终端可以在第一接入网设备停止服务后暂时先关闭物理层搜索和检测信号等功能，等到第二接入网设备再次 到达该终端设备所在的地理区域时或者达到之前(例如，终端设备可以通过第一时间信息确定第二接入网设备何时到达)，该终端设备再开启物理层搜索和检测信号等功能。
在另一种实施方式中，在该第二状态下，终端设备保持终端设备的上下文(例如，步骤503存储的终端设备的上下文)，在第二接入网设备再次到达能覆该终端设备的区域之前，终端设备不执行小区测量、小区下行同步以及读取系统消息，在第二接入网设备再次到达能覆该终端设备的区域时或之后，终端设备执行小区测量、小区下行同步以及读取系统消息)，但不会触发无线连接失败(radio link failure，RLF)流程，不会触发RRC重建流程。本实施方式中，当终端设备进入第二状态时，该终端设备可以先关闭物理层搜索和检测信号等功能，等到第二接入网设备再次到达该终端设备所在的地理区域时或者达到之前(例如，终端设备可以通过第一时间信息确定第二接入网设备何时到达)，该终端设备再开启物理层搜索和检测信号等功能。
由于，进入第二状态的终端设备不会触发无线连接失败RLF流程，不会触发RRC重建流程，有利于终端设备复用已有的RRC连接相关的配置，节省用于重建RRC连接的信令开销。此外，由于，终端设备在第二状态下可以暂时关闭物理层搜索和检测信号等功能，因此，有利于节省终端设备的能耗。
可选的，当终端设备再次与第二接入网设备发起建立连接时，该终端设备退出第二状态。
步骤503，终端设备根据该第一指示信息存储终端设备的上下文。
步骤504，第一接入网设备存储终端设备的上下文。
应注意，步骤503与步骤504无明确的时间先后顺序的限定。例如，终端设备先执行步骤503，再由第一接入网设备执行步骤504。又例如，第一接入网设备先执行步骤504，再由终端设备执行步骤503。又例如，终端设备执行步骤503的同时，第一接入网设备执行步骤504。
步骤505，第一接入网设备从第一区域移动至第二区域。
当第一接入网设备移动至第二区域(即第一接入网设备能够与核心网设备交互信息的区域)时，该第一接入网设备可以通过NTN网关与核心网设备建立连接并交互信息。
本实施例中，步骤501至步骤505与图3对应实施例中步骤301至步骤305类似，具体请参阅前文步骤301至步骤305中的相关描述，此处不予赘述。
步骤506，第一接入网设备向核心网设备发送上行NAS消息和终端设备的上下文。
相应地，核心网设备从第一接入网设备接收上行NAS消息和终端设备的上下文。
其中，终端设备的上下文用于该核心网设备确定的第二接入网设备与该终端设备建立连接。关于终端设备的上下文的具体介绍请参阅前文步骤304中的相关描述，此处不予赘述。关于上行NAS消息的具体介绍请参阅前文步骤306中的相关描述，此处不予赘述。需要说明的是，第一接入网设备可以通过一条消息向核心网设备发送上行NAS消息和终端设备的上下文，例如，第一接入网设备将上行NAS消息和终端设备的上下文携带在终端设备的初始消息(Initial UE Message)中发送给核心网设备。第一接入网设备也可以通过两条不同的消息向核心网设备发送上行NAS消息和终端设备的上下文，第一接入网设备将上行NAS消息携带在终端设备的初始消息(Initial UE Message)中发送给核心网设备，将终端设备的上下文携带在其他的消息中发送给核心网设备。
可选的，第一接入网设备向核心网设备发送第四指示信息，该第四指示信息用于指示该终端设备是在该第一接入网设备不能与该核心网设备交互信息时接入到该第一接入网设备。可选的，核心网设备在收到第四指示信息之后，基于第四指示信息生效第一NAS定时器或延迟启动第二NAS定时器。关于第四指示信息、第一NAS定时器和第二NAS定时器的介绍请参阅前文步骤301和步骤306中的相关描述，此处不予赘述。
可选的，第一接入网设备还可以向核心网设备发送第一时间信息，相应地，核心网设备还可以接收来自该第一接入网设备的第一时间信息。关于第一时间信息的介绍请参阅前文步骤301中的相关描述，此处不予赘述。
需要说明的是，第四指示信息、第一时间信息以及终端设备的上下文中至少一项可以携带于终端设备的初始消息中发送给核心网设备，也可以携带在其他消息中发送给核心网设备，此处不做限定。
步骤507，核心网设备向第二接入网设备发送下行NAS消息和终端设备的上下文。
相应地，第二接入网设备从核心网设备接收下行NAS消息和终端设备的上下文。
首先，核心网设备确定第二接入网设备，然后，核心网设备向第二接入网设备发送下行NAS消息和终端设备的上下文。
在一种可能的实施方式中，核心网设备可以基于终端设备的上下文和各个接入网设备的运行轨道信息确定第二接入网设备。由于，终端设备的上下文包括终端设备所在的地理位置信息，而核心网设备已知各个接入网设备的运行轨道信息，因此，该核心网设备可以基于终端设备所在的地理位置信息和各个接入网设备的运行轨道信息确定出运行轨道经过终端设备所在的地理区域的接入网设备为第二接入网设备。可选的，第二接入网设备可以是与第一接入网设备具有相同运行轨迹的接入网设备。
在另一种可能的实施方式中，核心网设备可以不考虑终端设备的上下文，仅基于各个接入网设备运行的轨道信息确定第二接入网设备。例如，核心网设备确定与第一接入网设备具有相同运行轨迹且运行在第一接入网设备之后的一个接入网设备作为第二接入网设备。
当核心网设备向第二接入网设备发送下行NAS消息时，核心网设备立即启动第一NAS定时器，或者，在第一时长之后启动第二NAS定时器。关于第四信息的介绍请参阅前文步骤306中的相关描述，此处不予赘述。
需要说明的是，当核心网设备向第二接入网设备发送下行NAS消息和终端设备的上下文时，该第二接入网设备已移动至第二区域，即第二接入网设备能够与核心网设备交互信息的区域。核心网设备可以向当前位于第二区域的第二接入网设备发送多条下行NAS消息，核心网设备也可以向当前位于第二区域的第二接入网设备发送一条下行NAS消息，此处不做限定。
需要说明的是，步骤505中第一接入网设备移动至的第二区域与步骤507中第二接入网设备所在的第二区域可能是不同的物理区域，也可能是相同的物理区域。第一接入网设备在步骤505中的第二区域与第二接入网设备在步骤507中的第二区域均能与核心网设备交互信息。
在一种示例中，第一接入网设备与第二接入网设备通过同一个NTN网关与核心网设备建立连接，第一接入网设备和第二接入网设备均位于前述同一个NTN网关提供服务的物理区域。在这种情况下，步骤505中第一接入网设备移动至的第二区域与步骤507中第二接入网设备所在的第二区域是相同的物理区域，即均为该NTN网关提供服务的区域。
在另一种示例中，第一接入网设备与第二接入网设备通过不同的NTN网关与核心网设备建立连接。例如，第一接入网设备通过NTN网关1与核心网设备建立连接并交互信息，第二接入网设备通过NTN网关2与核心网设备建立连接并交互信息。若NTN网关1提供服务的物理区域与NTN网关2提供服务的物理区域不同，则步骤505中第一接入网设备移动至的第二区域与步骤507中第二接入网设备所在的第二区域不同的物理区域，即分别为两个不同的NTN网关提供服务的区域。
步骤508，第二接入网设备存储终端设备的下行NAS消息和终端设备的上下文。
第二接入网设备收到来自核心网设备的下行NAS消息和终端设备的上下文之后，该第二接入网设备将该终端设备的下行NAS消息与终端设备的上下文对应存储。由于，该第二接入网设备此时还未与终端设备建立连接，因此，该第二接入网设备不会立即下发下行NAS消息。
步骤509，第二接入网设备从第二区域移动至第一区域。
由于，第二接入网设备从核心网设备接收了终端设备的上下文，而该终端设备的上下文中包含终端设备的地理区域信息，该地理区域信息能够指示终端设备所在的地理区域。因此，该第二接入网设备能够基于终端设备的上下文中的地理区域信息确定终端设备所在的地理区域。由于，该终端设备所在的地理区域位于所述第一区域中，在第二接入网设备移动至第一区域并且移动至终端设备所在的地理区域时，第二接入网设备将通过步骤510a或步骤510b触发终端设备执行步骤511，即第二接入网设备将通过步骤510a或步骤510b触发终端设备发起接入该第二接入网设备。
需要说明的是，步骤509中的第一区域和步骤501至步骤505中的第一区域可能是不同的地理区域，也可能是相同的地理区域。步骤509中的第一区域和步骤501至步骤505中的第一区域都包括了终端设备所在的地理区域。
步骤510a，第二接入网设备广播第一小区的小区标识信息。
相应地，终端设备从第二接入网设备接收第一小区的小区标识信息。
可选的，第一小区的小区标识信息可以携带于系统消息中。示例性的，第二接入网设备将在系统消息中广播该第一小区的小区标识信息，若终端设备在系统消息中收到第一小区的小区标识信息，而该终端设备的上下文又存储有第一小区的小区标识信息，则该终端设备触发接入该第二接入网设备。
步骤510b，第二接入网设备发送第三指示信息。
相应地，终端设备从第二接入网设备接收第三指示信息。
其中，第三指示信息用于指示该终端设备发起接入，也可以理解为，该第三指示信息用于指示终端设备触发接入到第二接入网设备。示例性的，该第三指示信息可以是向终端设备发送的使用终端设备的标识信息(例如，C-RNTI或第一标识信息)加扰的物理下行控制信道命令(PDCCH Order)；也可以是指示在终端设备的上下文中存储有第一小区的小区标识信息的终端设备的指示信息，例如，第三指示信息可以是第一小区的小区标识信息或指示第一小区的信息。当该终端设备接收来自该第二接入网设备的第三指示信息之后，该终端设备基于第三指示信息触发接入该第二接入网设备。具体请参阅前文步骤205中的相关描述，此处不予赘述。
可选的，该终端设备基于第三指示信息触发接入该第二接入网设备的第二小区。例如，第二接入网设备在第二小区广播第三指示信息，该终端设备在第二小区收到第三指示信息，则该终端设备触发接入该第二小区。其中，第二小区可以第二接入网设备中的任意一个小区。
步骤511，终端设备基于终端设备的上下文与第二接入网设备建立连接。
由于，终端设备存储有终端设备的上下文，第二接入网设备也存储有终端设备的上下文，并且，终端设备的上下文包含终端设备的AS配置信息，因此，终端设备与第二接入网设备仅需要进行上行同步便可以复用上下文中的AS配置信息建立连接。示例性的，终端设备可以先与第二接入网设备进行上下行同步，之后继续使用终端设备的上下文中的配置与第二接入网设备进行进一步的通信，从而第二接入网设备可以基于终端设备的上下文中的配置的时频资源和/或无线承载资源与第二接入网设备进行通信，而无需第二接入网设备重新执行RRC初始建立。
示例性的，终端设备通过如下步骤与第二接入网设备建立连接：
步骤511.1终端设备向第二接入网设备发送Msg1。
其中，Msg1包含随机接入前导(random access preamble，RAP)，RAP可能是PDCCH order中携带的，也可能是系统消息中广播的。若RAP携带于PDCCH Order中，则该RAP是第一接入网设备分配给该终端设备的，该RAP可以用于非竞争随机接入；若RAP是在系统消息中广播的随机接入配置中，则终端设备随机选择随机接入前导码，终端设备可以做基于竞争的随机接入。
步骤511.2，第二接入网设备向终端设备发送Msg2。
其中，该Msg2包含随机接入响应RAR、第二接入网设备为终端设备分配的临时的小区无线网络临时标识T-CRNTI以及上行定时提前量。
步骤512，终端设备向第二接入网设备发送终端设备的标识信息。
其中，终端设备的标识信息是终端设备的上下文中存储的C-RNTI和/或第一标识信息。
在一种可能的实施方式中，继步骤511.2之后，在Msg2的上行授权中，终端设备可以向第二接入网设备发送C-RNTI MAC CE，其中C-RNTI为终端设备初次接入第一接入网设备时分配的C-RNTI，并保存在终端设备上下中。
在一种可能的实施方式中，第一接入网设备在步骤302中为终端设备配置了第一标识信息，终端设备的上下文中存储有第一标识信息，则终端设备向第二接入网设备发送第一标识信息。
步骤513，第二接入网设备基于终端设备的标识信息确定终端设备的上下文。
当第二接入网设备收到的终端设备的标识信息的实现方式不同时，第二接入网设备确定终端设备的上下文的方式不同。下面分别进行介绍：
在一种可能的实施方式中，第二接入网设备从终端设备接收的是第一标识信息，则该第二接入网设备基于第一标识信息确定该终端设备的上下文。
在另一种可能的实施方式中，第二接入网设备从终端设备接收的是小区无线网络临时标识。当第二 接入网设备存储的终端设备的上下文包括该终端设备的地理区域信息和/或终端设备接入该第一接入网设备的时间信息时，该第二接入网设备基于该终端设备的地理区域信息和/或终端设备接入该第一接入网设备的时间信息，以及小区无线网络临时标识确定该终端设备的上下文。
在本实施方式的一种可能的示例中，第二接入网设备存储的终端设备的上下文包括该终端设备的地理区域信息，该第二接入网设备基于该终端设备的地理区域信息和小区无线网络临时标识确定该终端设备的上下文。
在本实施方式的另一种可能的示例中，第二接入网设备存储的终端设备的上下文包括终端设备接入该第一接入网设备的时间信息，该第二接入网设备基于终端设备接入该第一接入网设备的时间信息和小区无线网络临时标识确定该终端设备的上下文。
在本实施方式的另一种可能的示例中，第二接入网设备存储的终端设备的上下文包括终端设备的地理区域信息和终端设备接入该第一接入网设备的时间信息，该第二接入网设备基于终端设备的地理区域信息、终端设备接入该第一接入网设备的时间信息和小区无线网络临时标识确定该终端设备的上下文。
本实施例中，第二接入网设备基于前述任意一种实施方式确定终端设备的上下文之后，该第一接入网设备与终端设备可以继续交互NAS消息。
步骤514，第二接入网设备基于终端设备的上下文确定终端设备的下行NAS消息。
需要说明的是，第二接入网设备可能基于终端设备的上下文确定了多条该终端设备的下行NAS消息，也可能基于终端设备的上下文仅确定一条该终端设备的下行NAS消息。可选的，第二接入网设备基于终端设备的上下文确定的终端设备的下行NAS消息的数量与第二接入网设备在第二区域从核心网设备接收的下行NAS消息的数量相同。
步骤515，第二接入网设备向终端设备转发下行NAS消息。
可选的，第二接入网设备还将更新终端设备的上下文中与NAS相关的信息(即终端设备的NAS上下文)。例如，第二接入网设备将转发给终端设备的下行NAS消息存储至终端设备的上下文中，或者，第二接入网设备存储一个指示信息以指示该第二接入网设备向终端设备转发了哪个下行NAS消息。
步骤516，终端设备向第二接入网设备发送上行NAS消息。
其中，该上行NAS消息可以是与步骤315中的下行NAS消息对应的消息。示例性的，该上行NAS消息是该下行NAS消息的响应消息。具体与前文步骤316类似，此处不予赘述。
步骤517，第二接入网设备存储终端设备的上行NAS消息。
在一种可能的实施方式中，第二接入网设备将接收到的上行NAS消息存储在终端设备上下文中。
在另一种可能的实施方式中，第二接入网设备将接收到的上行NAS消息与终端设备上下文建立映射关系，以使得第二接入网设备根据终端设备的上下文可以查询到需要透传给核心网设备的上行NAS消息。
步骤518，第二接入网设备从第一区域移动至第二区域。
第二接入网设备移动至第二区域之后，该第二接入网设备与核心网设备建立连接。
需要说明的是，步骤518中第二接入网设备到达的第二区域与步骤505中第一接入网设备到达的第二区域，可能是相同的物理区域，也可能是不同的物理区域，具体请参阅步骤507中相关示例的介绍，此处不予赘述。
还需要说明的是，步骤518中第二接入网设备到达的第二区域与步骤507中第二接入网设备到达的第二区域，可能是相同的物理区域，也可能是不同的物理区域。
在一种示例中，第二接入网设备两次均通过同一个NTN网关与核心网设备建立连接，第二接入网设备两次均位于前述同一个NTN网关提供服务的物理区域。在这种情况下，步骤507中第二接入网设备移动至的第二区域与步骤518中第二接入网设备移动至的第二区域是相同的物理区域，即均为该NTN网关提供服务的区域。
在另一种示例中，第二接入网设备两次通过不同的NTN网关与核心网设备建立连接。例如，在步骤507中，第二接入网设备通过NTN网关a与核心网设备建立连接并交互信息；在步骤518中，第二接入网设备通过NTN网关b与核心网设备建立连接并交互信息。若NTN网关a提供服务的物理区域与 NTN网关b提供服务的物理区域不同，则步骤507中第二接入网设备移动至的第二区域与步骤518中第二接入网设备移动至的第二区域不同的物理区域，即分别为两个不同的NTN网关提供服务的区域。例如，NTN网关a是第二接入网设备即将为终端设备提供服务之前，搜索到的最后一个NTN网关，NTN网关b是第二接入网设备停止为终端设备提供服务后搜索到的第一个NTN网关。
步骤519，第二接入网设备向核心网设备发送上行NAS消息和终端设备的上下文。
相应地，核心网设备从第二接入网设备接收上行NAS消息和终端设备的上下文。
需要说明的是，若NAS信令还未交互完，则该核心网设备将再确定另一个第二接入网设备继续与终端设备交互NAS信令。为便于介绍，称步骤519中的第二接入网设备为第二接入网设备#1，称步骤519之后核心网设备确定的第二接入网设备为第二接入网设备#2。核心网设备在收到来自第二接入网设备#1的上行NAS消息和终端设备的上下文之后，核心网设备基于终端设备的上下文确定运行轨道上另一个可以经过终端设备所在的地理区域的第二接入网设备#2，然后，向第二接入网设备#2发送下一条下行NAS消息和终端设备的上下文，第二接入网设备#2存储收到的下行NAS消息和终端设备的上下文。待第二接入网设备#2移动至第一区域中终端设备所在的地理位置之后，第二接入网设备#2与终端设备建立连接，并向终端设备发送存储的下行NAS消息，以及从终端设备接收终端设备回复上行NAS消息，并存储该上行NAS消息。待第二接入网设备#2再次移动至第二区域时，第二接入网设备#2再次与核心网设备建立连接，并向核心网设备发送存储的上行NAS消息。具体过程与步骤507至步骤519类似，此处不予赘述。
为便于理解，以图6A和图6B为例介绍本实施例的方案。如图6A所示，当第一接入网设备位于第一区域(例如，没有NTN网关覆盖的区域)时，该第一接入网设备通过第一指示信息知会终端设备该第一接入网设备未与核心网设备建立连接。待该终端设备接入该第一接入网设备之后，终端设备和第一接入网设备均能够存储终端设备的上下文，并且，第一接入网设备还会存储从终端设备接收的初始NAS消息(即携带在Msg5中的上行NAS消息，例如，注册请求消息)。当第一接入网设备停止为终端设备提供服务之后，第一接入网设备沿着运行轨道从第一区域移动至第二区域(例如，有NTN网关覆盖的区域)。位于第二区域的第一接入网设备与核心网设备建立连接，并通过NTN网关向核心网设备发送初始NAS消息和终端设备的上下文，以使得核心网设备确定第二接入网设备#1。然后，核心网设备通过NTN网关向第二接入网设备#1发送下行NAS消息1。如图6B所示，当第二接入网设备#1移动至第一区域(包括该终端设备所在的地理区域)时，第二接入网设备#1基于从核心网设备接收的终端设备的上下文快速与终端设备建立连接。在连接建立后，第二接入网设备#1向终端设备发送下行NAS消息1，终端设备向第一接入网设备回复响应于下行NAS消息1的上行NAS消息1。当第二接入网设备#1停止为终端设备提供服务之后，第二接入网设备#1再次从第一区域移动至第二区域(例如，有NTN网关覆盖的区域)。位于第二区域的第二接入网设备#1再次与核心网设备建立连接，并通过NTN网关向核心网设备发送上行NAS消息1。可选的，若还存在需要交互的NAS信令(例如，下行NAS消息2)，则核心网设备可以确定第二接入网设备#2，并通过NTN网关向第二接入网设备#2发送下行NAS消息2和终端设备的上下文，进而使得第二接入网设备#2按照与第二接入网设备#1类似的方式继续交互NAS信令。通过多次NAS信令交互，终端设备和核心网之间NAS注册成功，进而该终端设备可以获得网络服务。
本实施例中，由于，终端设备和第一接入网设备均能够存储终端设备的上下文以保留终端设备接入第一接入网设备时使用的配置信息(例如，时频资源、无线承载等配置信息)，并且，第一接入网设备还能够将终端设备的上下文转发给核心网设备，以使得当第一接入网设备停止为终端设备提供服务后，核心网设备能够为终端设备选择第二接入网设备继续为终端设备提供服务。当第二接入网设备到达终端设备所在的地理区域时，由于，第二接入网设备具有从核心网设备接收的来自第一接入网设备的终端设备的上下文，因此，终端设备与第二接入网设备能够基于终端设备的上下文快速完成上下行同步并继续交互NAS信令，而不需要终端设备在第二接入网设备重新进行RRC的初始建立。因此，不仅有利于节省与第二接入网设备建连的信令开销，有利于提高终端设备接入第二接入网设备的效率。由于，当第二接入网设备停止为终端设备提供服务之前，该第二接入网设备还会将更新后的终端设备的上下文发送给核心网设备，以使得核心网设备通过下一个第二接入网设备继续为终端设备提供服务。由于，每一个携 带终端设备的上下文备每次到达终端设备所在的地理区域时，能够快速接纳终端设备并继续与终端设备交互NAS信令，因此，有利于通过第二接入网设备快速交互完NAS信令而完成终端设备在核心网侧的注册流程，进而使得有利于提高通信效率，使得位于没有NTN网关覆盖的区域的终端设备也能够获得网络服务。
下面将结合图7对本申请的通信方法的另一个实施例进行介绍。本实施例中，当终端设备在核心网设备完成注册后，若终端设备进入空闲态，则核心网设备可以基于图7所介绍的方式寻呼终端设备。需要说明的是，终端设备可以通过图2、图3或图5对应实施例中任意一种实施例提供的方式在核心网设备完成注册，也可以采用传统技术中其他的方式在核心网设备完成注册，本实施例不限制。具体地，核心网设备、接入网设备和终端设备将执行如下步骤。
步骤701，核心网设备根据终端设备的地理区域信息确定至少一个接入网设备。
由于，终端设备在注册到核心网设备之后，该核心网设备存储有终端设备的上下文，该终端设备的上下文包括终端设备的地理区域信息，终端设备的地理区域信息用于指示该终端设备所在的地理区域。当核心网设备需要向终端设备发起寻呼时，该核心网设备基于核心网设备存储的终端设备的地理区域信息确定至少一个接入网设备，该至少一个接入网设备用于寻呼该终端设备(即位于该地理区域信息指示的地理区域的终端设备)。
其中，至少一个接入网设备中的每个接入网设备的覆盖区域的移动路径能够经过终端设备所在的地理区域。也可以理解为，核心网设备确定的接入网设备是在未来能够移动至终端设备所在的地理区域的接入网设备。
需要说明的是，核心网设备确定的接入网设备可以是当前能够通过NTN网关与核心网设备建立连接的接入网设备，也可以是当前不能够通过NTN网关与核心网设备建立连接但未来能够能够通过NTN网关与核心网设备建立连接或交互信息的接入网设备。示例性的，若核心网设备确定的接入网设备可以是当前能够通过NTN网关与核心网设备建立连接或交互信息的接入网设备，则一般该接入网设备当前的覆盖区域不包括终端设备所在的地理区域。若核心网设备确定的接入网设备可以是当前不能够通过NTN网关与核心网设备建立连接或交互信息的接入网设备，则核心网设备也是等该接入网设备能够通过NTN网关与核心网设备建立连接或交互信息时，核心网设备才会将一些信息(例如寻呼消息)发送给该接入网设备。其中，终端设备的地理区域信息可能是跟踪区域TAC、也可能是由经纬度表示的地理区域，终端设备的地理区域信息还可能是终端设备当前所在跟踪区域TAC所述的跟踪区域列表(tracking area list，TAL)。可以理解的是，终端的地理区域是一个逻辑上的概念，主要用来给核心网选择寻呼接入网设备使用的。例如，地理区域信息可以是终端设备接入时的PLMN+TAC，核心网根据PLMN+TAC将接下来运行轨迹会经过终端设备所在区域的接入网设备确定为用于寻呼终端设备的接入网设备。该核心网设备可能确定了1个接入网设备，也可能为了提高寻呼成功率确定多个接入网设备。其中，核心网设备确定的多个接入网设备可能是同时选择出来的，也可能是先后多次选择出来的，此处不做限定。
以终端设备的地理区域信息为TAC为例。若终端设备位于TAC1指示的区域，核心网设备确定的至少一个接入网设备中每个接入网设备均能够移动至TAC1指示的区域(即这些接入网设备都能为TAC1指示的区域提供服务)，但是，前述接入网设备当前与核心网设备建立连接时可能不在TAC1指示的区域。例如，接入网设备1当前与核心网设备建立连接时位于TAC2指示的区域，但是，该接入网设备1未来能够运行至TAC1指示的区域。
可选的，若核心网设备在终端设备注册阶段收到第四指示信息，或者，核心网设备存储的终端设备的上下文包括第四指示信息，该第四指示信息用于指示该终端设备是在该第一接入网设备不能与该核心网设备交互信息时接入到该第一接入网设备。关于第四指示信息的具体介绍请参阅前文步骤306，此处不予赘述。在这种情况下，核心网设备可以基于第四指示信息触发按照本实施例提供的方式寻呼终端设备。若核心网设备在终端设备注册阶段未收到第四指示信息，或者，核心网设备存储的终端设备的上下文不包括第四指示信息，则核心网设备按照传统技术从终端设备的跟踪区域TA列表确定用于寻呼终端设备的接入网设备。例如，核心网设备向TA列表中的全部接入网设备发起寻呼。
可选的，核心网设备有预配置的TAC列表信息，预配置的TAC列表信息用于指示在该TAC列表中的终端设备仅能够采用动态连接的方式与核心网设备和接入网设备连接。其中，动态连接指由于接入网设备与NTN网关或核心网之间的链路不是一直存在或可用的场景下，终端设备发送给核心网设备的信息需要经过接入网设备先存储，并在接入网设备沿着轨道运行一段时间之后再与核心网设备连接并转发给核心网设备的过程。与动态连接相对的是静态连接。静态连接指由于接入网设备与NTN网关或核心网之间的链路是一直存在或可用的场景下，终端设备发送给核心网设备的信息可以由接入网设备直接转发，而不需要先存储再转发。
此外，该预配置的TAC列表信息可以配置在核心网设备中，也可以在操作、管理和维护(operations，administration and maintenance，OAM)中统一管理并由OAM下发给核心网设备。具体预配置形式不做限定。当终端设备的TAC位于预配置的TAC列表信息中时，核心网设备基于本实施例中提供的方式寻呼终端设备。
步骤702，核心网设备向至少一个接入网设备发送寻呼消息。
可选的，核心网设备在发送寻呼消息时，核心网设备启动第一寻呼定时器。
其中，第一寻呼定时器是终端设备处于store and forward模式时核心网设备使用的寻呼定时器；也可以理解为，第一寻呼定时器是终端设备位于store and forward模式的地理区域时核心网设备使用的寻呼定时器；也可以理解为，第一寻呼定时器是核心网设备从接入网设备接收到第四指示信息时使用的寻呼定时器。
需要说明的是，若终端设备未处于store and forward模式，终端设备也未位于store and forward模式的地理区域，核心网设备也没有收到第四指示信息，则核心网设备在发送寻呼消息时启动预配置的寻呼定时器。其中，第一寻呼定时器的时长大于预配置的寻呼定时器的时长。预配置的寻呼定时器的时长可以是网络管理设备配置的，也可以是协议预定义的，此处不做限定。
若在第一寻呼定时器的运行期间核心网设备能够收到终端设备的响应消息，则核心网设备寻呼终端设备成功；若在第一寻呼定时器的运行期间核心网设备没有收到终端设备的响应消息，则核心网设备寻呼终端设备失败。按照现有寻呼流程，后续可以做寻呼的重试流程。
相应地，接入网设备从核心网设备接收寻呼消息。其中，寻呼消息包括终端设备的地理区域信息。由于，终端设备的地理区域信息指示的地理区域与接入网设备接收寻呼消息时所在的地理区域不一致，则接入网设备将存储从核心网设备收到的寻呼消息，而不是立即下发寻呼消息。
以终端设备的地理区域信息为TAC为例。若寻呼消息携带的终端设备的地理区域信息为TAC1，表示终端设备位于TAC1指示的区域，而该接入网设备1在TAC1指示的区域从核心网设备收到寻呼消息，则该接入网设备存储该寻呼消息，而不是立即下线该寻呼消息。
步骤703，至少一个接入网设备移动至终端设备所在的地理区域。
需要说明的是，至少一个接入网设备可能分别在不同时刻到达终端设备所在的地理区域，也可能存在两个或多个接入网设备同时到达终端设备所在的地理区域，此处不做限定。
可选的，至少一个接入网设备包括第三接入网设备和第四接入网设备，第四接入网设备为在第三接入网设备停止为终端设备提供服务后为终端设备提供服务的接入网设备，即第三接入网设备相比于第四接入网设备更早到达终端设备所在的地理区域。例如，第三接入网设备为至少一个接入网设备中第一个到达终端设备所在的地理区域的接入网设备，第四接入网设备为至少一个接入网设备中第二个到达终端设备所在的地理区域的接入网设备。
步骤704，至少一个接入网设备在终端设备所在的地理区域发送寻呼消息。
相应地，终端设备从至少一个接入网设备接收寻呼消息。
在一种可能的实施方式中，至少一个接入网设备中每个接入网设备到达终端设备所在的地理区域时，每个接入网设备均在终端设备所在的地理区域发送寻呼消息。例如，当第三接入网设备移动至终端设备所在的地理区域时，第三接入网设备在终端设备所在的地理区域发送寻呼消息；当第四接入网设备移动至终端设备所在的地理区域时，第四接入网设备在终端设备所在的地理区域发送寻呼消息。
在一种可能的实施方式中，终端设备在收到第一个寻呼消息(例如，来自第三接入网设备的寻呼消 息)之后，该终端设备对该寻呼消息进行处理，并且，在该寻呼消息处理完成前或在响应该寻呼消息之前(例如从收到第一个寻呼消息到终端设备触发接入无线网络之前)，不再接收或处理后续的寻呼消息。
在一种示例中，若终端设备的AS收到寻呼消息，则终端设备的AS通知终端设备的NAS，以使得终端设备的NAS对寻呼消息进行处理。当终端设备的NAS开始处理寻呼消息之后，终端设备的NAS通知终端设备的AS不再监听其他的寻呼消息。由于，能够减少终端设备接收寻呼消息的次数，因此，有利于节省终端设备的能耗。
在另一种示例中，若终端设备的AS收到寻呼消息，则终端设备的AS通知终端设备的NAS，以使得终端设备的NAS对寻呼消息进行处理。当终端设备的NAS开始处理寻呼消息之后，终端设备的NAS不再从终端设备的AS接收寻呼消息，终端设备的AS即使收到寻呼消息也不再转发给终端设备的NAS。由于，能够减少终端设备处理寻呼消息的次数，因此，有利于节省终端设备的能耗。
在另一种可能的实施方式中，至少一个接入网设备中仅有部分接入网设备在到达终端设备所在的地理区域时广播寻呼消息。例如，当第三接入网设备移动至终端设备所在的地理区域时，第三接入网设备在终端设备所在的地理区域发送寻呼消息；当第四接入网设备移动至终端设备所在的地理区域时，第四接入网设备不发送发送寻呼消息。
在一种示例中，若第三接入网设备与第四接入网设备之间存在星间链路，当第三接入网设备未成功寻呼终端设备时(例如，未收到该终端设备对寻呼消息的响应)，第四接入网设备继续寻呼终端设备；当第三接入网设备成功寻呼终端设备时，第三接入网设备向第四接入网设备发送第五指示信息，第五指示信息用于指示第四接入网设备删除用于寻呼终端设备的寻呼消息或指示第四接入网设备无需寻呼该终端设备。第三接入网设备还可以向第四接入网设备指示终端设备的标识，这样第四接入网设备就能知道第五指示信息对应的终端设备，即删除哪些终端设备的寻呼消息或无需寻呼哪些终端设备。由于，能够减少第四接入网设备不必要的寻呼开销，因此，有利于减少整网中的信令开销。
本实施例中，核心网设备能够基于终端设备的地理区域信息确定至少一个用于寻呼终端设备的接入网设备，而不是直接基于TA列表确定用于寻呼终端设备的接入网设备，有利于提高核心网设备成功寻呼终端设备的几率。
下面将结合图8对本申请的通信方法的另一个实施例进行介绍。本实施例中，当终端设备在核心网设备完成注册后，若核心网设备有下行数据发送，则核心网设备可以基于图8所介绍的方式下发数据。需要说明的是，终端设备可以通过图2、图3或图5对应实施例中任意一种实施例提供的方式在核心网设备完成注册，也可以采用其他的方式在核心网设备完成注册，本实施例不限制。具体地，核心网设备、接入网设备和终端设备将执行如下步骤。
步骤801，核心网设备向第五接入网设备发送终端设备的多个数据包，每个数据包对应一个第一序列号。
相应地，第五接入网设备从核心网设备接收终端设备的多个数据包，每个数据包对应一个第一序列号。
其中，第五接入网设备是核心网设备确定的用于向终端设备转发下行数据的接入网设备。核心网设备存储有终端设备的上下文，该核心网设备可以基于终端设备的上下文确定的用于向终端设备转发下行数据的接入网设备。可选的，终端设备的上下文包括终端设备的地理区域信息。核心网设备根据终端设备的地理区域信息确定至少一个接入网设备，该至少一个接入网设备用于向终端设备转发下行数据。其中，每个接入网设备当前的覆盖区域不包括终端设备所在的地理区域，接入网设备的覆盖区域的移动路径经过终端设备所在的地理区域。具体地，可以参阅前文步骤701，此处不予赘述。
可选的，至少一个接入网设备包括第五接入网设备。示例性的，第五接入网设备为至少一个接入网设备中第一个到达终端设备所在的地理区域的接入网设备。需要说明的是，第五接入网设备与图3或图5对应实施例中的第一接入网设备可能是同一接入网设备，也可能是不同的接入网设备。后文以第五接入网设备为例进行介绍。
此外，前述多个数据包中的每个数据包对应一个第一序列号，该第一序列号是由核心网设备生成的。 示例性的，该第一序列号可以是通用分组无线业务隧道协议用户平面序列号(GPRS tunneling protocol user plane serial number，GTPU SN)，也可以是其他的用于标记数据包的序号，此处不做限定。需要说明的是，核心网设备发送的每个数据包均携带了该数据包对应的第一序列号。
可选的，第五接入网设备向核心网设备发送终端设备的上下文。其中，终端设备的上下文包括与AS相关的信息(即AS上下文)和与NAS相关的信息(即NAS上下文)。
示例性的，终端设备的AS上下文包括终端设备的标识信息(例如，终端设备初始接入时接入网设备配置的C-RNTI等)，接入网设备为该终端设备配置的资源相关的信息(例如，小区资源配置信息(cell group configuration)以及无线承载配置(radio bear configuration)等)，终端设备接入的小区的标识信息(例如，全球小区标识(cell global identifier，CGI)、物理小区标识(physical cell identifier，PCI)等)以及其他的与Uu口相关的信息。
示例性的，终端设备的NAS上下文包括终端设备已发送的上行NAS消息，终端设备已经启动的相关NAS定时器，终端设备的状态信息，安全相关信息，终端设备的能力信息，IMSI以及其他的与核心网相关的NG口的信息。
步骤802，第五接入网设备移动至终端设备所在的地理区域。
步骤803，第五接入网设备向终端设备发送携带第一序列号和/或第二序列号的数据包。
相应地，终端设备从第五接入网设备接收携带第一序列号和/或第二序列号的数据包。
在一种可能的实施方式中，第五接入网设备向终端设备发送仅携带第一序列号的数据包。示例性的，第五接入网设备按照从核心网设备接收到的数据顺序向终端设备发送数据包。例如，若核心网设备按照第一序列号从小到大向第五接入网设备发送数据包，则第五接入网设备按照第一序列号从小到大向终端设备发送数据包。
需要说明的是，终端设备在收到来自第五接入网设备的数据包之后，终端设备将向第五接入网设备发送接收数据包的反馈，以指示是否成功接收数据包。具有可以有如下多种实现方式：
一种实现方式中，终端设备每成功接收一个数据包，则该终端设备便向第五接入网设备回复一个表示确认接收的指示(例如，确认字符(acknowledge character，ACK))。该表示确认接收的指示表示终端设备已经接收到的第一序列号的数据包。
示例性的，第五接入网设备从核心网设备收到5个数据包，5个数据包的第一序列号分别为1、2、3、4和5，则第五接入网设备先发送序列号为1的数据包，再发送序列号为2的数据包，以此类推。该终端设备在收到序列号为1的数据包之后，会向第五接入网设备回复序列号为1的ACK，该终端设备在收到序列号为2的数据包之后，会向第五接入网设备回复序列号为2的ACK，以此类推。
另一种实现方式中，终端设备接收来自第五接入网设备的反馈报告指示，该反馈报告指示可以是包含在某一个数据包中。若终端设备收到该包含反馈报告指示的数据包以及之前所有的数据包，则终端设备向第五接入网设备反馈ACK；若终端设备收到该包含反馈报告指示的数据包，但是，该包含反馈报告指示的数据包之前的数据未完全收到，则终端设备向第五接入网设备反馈未成功接收的数据包的序列号。
示例性的，第五接入网设备从核心网设备收到了5个数据包，5个数据包的第一序列号分别为1、2、3、4和5，并且，第一序列号为5的数据包中包含反馈报告指示。若终端设备收到前述5个数据包，则终端设备向第五接入网设备反馈ACK；若终端设备仅收到该包含反馈报告指示的数据包(即第一序列号为5的数据包)，但是，该包含反馈报告指示的数据包之前的数据未完全收到(例如，仅收到第一序列号为1、2、3的数据包)，则终端设备向第五接入网设备反馈未成功接收的数据包的序列号(即第一序列号4)。
可选的，第五接入网设备还可以根据终端设备在RLC层反馈的RLC层的数据包的正确接收情况确定从核心网设备接收的数据包是否被终端设备正确接收。
在另一种可能的实施方式中，第五接入网设备基于每个数据包的第一序列号和第一映射规则确定每个数据包的第二序列号，然后，第五接入网设备向终端设备发送携带第二序列号的数据包。可选的，发送的数据包除了携带第二序列号之外，还可以携带第一序列号。示例性的，该第二序列号为PDCP SN。
示例性的，第五接入网设备从核心网设备收到5个数据包，5个数据包的第一序列号分别为1、2、3、4和5，则第五接入网设备先基于每个数据包的第一序列号和第一映射规则确定每个数据包的第二序列号。例如，第一序列号1基于第一映射规则确定的第二序列号为A，第一序列号2基于第一映射规则确定的第二序列号为B，以此类推，第五接入网设备能够确定5个数据包的第二序列号分别为A、B、C、D和E。然后，第五接入网设备先向终端设备发送序列号为A的数据包，再发送序列号为B的数据包，以此类推。
需要说明的是，终端设备在收到来自第五接入网设备的数据包之后，终端设备将向第五接入网设备发送接收数据包的反馈，以指示是否成功接收数据包。具体地，与前述实施方式中的反馈方式类似，此处不予赘述。
可选的，第五接入网设备还可以根据终端设备在RLC层反馈的RLC层的数据包的正确接收情况确定从核心网设备收到的数据包是否被终端设备正确接收。
需要说明的是，核心网设备确定的至少一个接入网设备具有相同的第一映射规则。
步骤804，第五接入网设备向终端设备发送第六指示信息。
相应地，终端设备从第五接入网设备接收第六指示信息。
步骤804为可选的步骤。
第五接入网设备在停止为终端设备提供服务之前，若第五接入网设备还存在需要向终端设备发送的数据包，或者，还存在已发送的数据包未收到ACK，则第五接入网设备向终端设备发送第六指示信息，第六指示信息用于指示存在待发送的数据包。其中，待发送的数据包可以是未成功发送的数据包，即第五接入网设备已发送但未收到ACK的数据包；也可以是未发送的数据包，即第五接入网设备从未发送的数据包。可选的，第六指示信息可能是MAC CE的形式，也可以是MAC PDU(例如，在PDCP层或RLC层携带第六指示信息)的形式，具体指示形式不限定。
在一种可能的实施方式中，第六指示信息为第一数量信息，第一数量信息为第五接入网设备从核心网设备接收的终端设备的数据包的总量。终端设备基于已接收的数据包的数量和第一数量信息确定是否还有未接收的数据包。例如，第五接入网设备从核心网设备收到5个数据包，则第一数量信息为5，若终端设备已接收3个数据包，则该终端设备能够确定还存在待接收的数据包。
在另一种可能的实施方式中，第六指示信息为第二数量信息，第二数量信息为第五接入网设备中待发送的数据包的数量。若第二数量信息的取值为0，则表示第五接入网设备不存在待发送的数据包；若第二数量信息的取值为非0，则表示第五接入网设备存在待发送的数据包。
需要说明的是，步骤804为可选的步骤，若第五接入网设备没有执行步骤804，当第五接入网设备停止为终端设备提供服务时，该终端设备没有收到来自第五接入网设备的释放或挂起(suspend)连接的指示，则终端设备确定该第五接入网设备中还存在待发送的数据包。
需要说明的是，步骤804为可选的步骤，若第五接入网设备没有执行步骤804，当第五接入网设备停止为终端服务后，终端设备接入到第六接入网设备后(步骤807)，由终端设备实现决定是否向第六接入网设备发送步骤808。
步骤805，核心网设备向第六接入网设备发送终端设备的上下文和终端设备的多个数据包，每个数据包对应一个第一序列号。
可选的，至少一个接入网设备除了包括第五接入网设备之外，还包括第六接入网设备，第六接入网设备为在第五接入网设备停止为终端设备提供服务后为终端设备提供服务的接入网设备，即第五接入网设备相比于第六接入网设备更早到达终端设备所在的地理区域。示例性的，第五接入网设备为至少一个接入网设备中第一个到达终端设备所在的地理区域的接入网设备，第六接入网设备为至少一个接入网设备中第二个到达终端设备所在的地理区域的接入网设备。
由于，接入网设备具有移动的特性(例如，第五接入网设备能够在运行轨道移动)，单个接入网设备为终端设备服务的时间有限，因此，单个接入网设备可能无法传输完所有需要发送给终端设备的数据，因此，核心网设备除了向第五接入网设备发送多个数据包，还向第六接入网设备发送终端设备的上下文和终端设备的多个数据包，每个数据包对应一个第一序列号，以使得第六接入网设备继续向终端设备发 送下行数据包。
需要说明的是，步骤805可以与步骤801同时执行，也可以在步骤801之后且步骤806之前执行，此处不做限定。
步骤806，第六接入网设备移动至终端设备所在的地理区域。
步骤807，终端设备与第六接入网设备建立连接。
示例性的，第六接入网设备基于终端设备的上下文与终端设备建立连接。
需要说明的是，终端设备与第六接入网设备建立连接的过程可以按照前文图3对应实施例(例如，步骤311)或前文图5对应实施例(例如，步骤511)提供的方式实现，也可以采用其他的方式实现终端设备与第六接入网设备之间连接的建立，本实施例不对终端设备与第六接入网设备建立连接的方式进行限定。
步骤808，终端设备向第六接入网设备发送第七指示信息。
相应地，第六接入网设备从终端设备接收第七指示信息。
其中，第七指示信息用于指示终端设备已连续成功接收的数据包，和/或，终端设备待接收的下一个数据包。其中，第七指示信息包括目标序列号。
在一种可能的实施方式中，目标序列号为终端设备已连续确认接收的最后一个数据包的序列号。例如，终端设备已接收序列号为1的数据包、序列号为2的数据包序列号为3的数据包以及序列号为5的数据包，则目标序列号为3，用于指示第六接入网设备从序列号4开始发送数据包。
在另一种可能的实施方式中，目标序列号包括终端设备已连续确认接收的数据包之后的第一个数据包的序列号。例如，终端设备已接收序列号为1的数据包、序列号为2的数据包、序列号为3的数据包以及序列号为5的数据包，则第七指示信息包括的序列号为4，用于指示第六接入网设备从序列号4开始发送数据包。
在另一种可能的实施方式中，目标序列号包括最后一个接收的数据包的序列号以及在最后一个接收的数据包之前未ACK的数据包的序列号。例如，终端设备已接收序列号为1的数据包、序列号为2的数据包、序列号为3的数据包以及序列号为5的数据包，则第七指示信息则反馈序列号5和序列号4，表示最后一个接收到的数据包的序列号是5，未接收到的数据包的序列号为4。
在另一种可能的实施方式中，目标序列号包括最后一个接收的数据包之后的一个数据包的序列号以及在最后一个接收的数据包之前未ACK的数据包的序列号。例如，终端设备已接收序列号为1的数据包、序列号为2的数据包、序列号为3的数据包以及序列号为5的数据包，则第七指示信息则反馈序列号6和序列号4，表示最新要发送的数据包的序列号是6，已发送的数据包里未接收到的数据包的序列号为4，可以重发序列号为4的数据包。
在另一种可能的实施方式中，目标序列号包括指示哪些数据包被正确接收或哪些数据包没有被正确接收。例如，终端设备已接收序列号为1的数据包、序列号为2的数据包、序列号为3的数据包以及序列号为5的数据包，则第七指示信息则反馈序列号为1、2、3和5的数据包已被终端设备正确接收。
在实际应用中，可以采用前述任意一种实施方式实现第七指示信息。
需要说明的是，若第六接入网设备向终端设备发送的是包含第一序列号的数据包，则第七指示信息中序列号指的是第一序列号；若第六接入网设备向终端设备发送的是第二序列号，则第七指示信息里指示的序列号是第二序列号。
步骤809，第六接入网设备根据第七指示信息向终端设备发送数据包。
相应地，终端设备从第六接入网设备接收数据包。
可选的，第六接入网设备基于第七指示信息向终端设备发送数据包。第六接入网设备基于收到的第七指示信息指示的序列号和第六接入网设备从核心网设备收到的数据包相比较。若第六接入网设备确定终端设备已经收到了核心网设备下发的全部数据包，则第六接入网设备不向终端设备下发数据包；若当终端设备未全部收到核心网设备下发的全部数据包，则第六接入网根据第七指示信息向终端设备下发数据包。
可选的，目标序列号可以是第一序列号，也可以是第二序列号。下面分别进行介绍：
在一种可能的实施方式中，目标序列号为第一序列号。第六接入网设备向终端设备发送携带第一序列号的至少一个数据包，至少一个数据包中每个数据包的第一序列号大于或等于目标序列号。具体示例请参阅步骤808中关于第七指示信息的介绍，此处不予赘述。
在另一种可能的实施方式中，目标序列号为第二序列号。第六接入网设备基于每个数据包的第一序列号和第一映射规则确定每个数据包的第二序列号；第六接入网设备向终端设备发送携带第二序列号的至少一个数据包，至少一个数据包中每个数据包的第二序列号大于或等于目标序列号。
示例性的，以目标序列号为终端设备已连续确认接收的最后一个数据包的序列号为例。终端设备已接收序列号为A的数据包、序列号为B的数据包以及序列号为C的数据包，则目标序列号为C。第六接入网设备基于序列号为4的数据包确定该数据包的第二序列号为D，基于序列号为5的数据包确定该数据包的第二序列号为E。然后，第六接入网设备继续向终端设备发送序列号为D的数据包和序列号为E的数据包，以此类推。
本实施例中，由于核心网设备能够复制终端设备的多个数据包并向多个接入网设备发送该终端设备的数据包，以及向多个接入网设备发送终端设备的上下文。进而当其中一个接入网设备不能将全部的数据包发送给终端设备时，能够通过其他的接入网设备将数据包发送给终端设备。有利于保持终端设备接收的数据的连续性。
相应于前文方法实施例给出的方案，本申请实施例还提供了相应的通信装置(有时也称为通信设备)和通信系统，所述通信装置包括用于执行上述实施例中每个部分相应的模块或单元。所述模块或单元可以是软件，也可以是硬件，或者是软件和硬件结合。下文仅对通信装置和系统进行了简要说明，对于方案实现细节，可以参考前述方法实施例的描述，下文不再赘述。
如图9所示，为本实施例提供的一种通信装置90的结构示意图。应当理解的是，前述图2、图3、图5、图7或图8对应的方法实施例中的终端设备可以基于本实施例中图9所示的通信装置90的结构。
通信装置90包括至少一个处理器901、至少一个存储器902和至少一个收发器903。其中，处理器901、存储器902和收发器903相连。可选地，通信装置90还可以包括输入设备905、输出设备906和一个或多个天线904。其中，天线904与收发器903相连，输入设备905、输出设备906与处理器901相连。
本实施例中，存储器902主要用于存储软件程序和数据。存储器902可以是独立存在，与处理器901相连。可选地，存储器902可以和处理器901集成于一体，例如集成于一个或多个芯片之内。其中，存储器902能够存储执行本申请实施例的技术方案的程序代码，并由处理器901来控制执行，被执行的各类计算机程序代码也可被视为是处理器901的驱动程序。应当理解的是，本实施例中的图9仅示出了一个存储器和一个处理器，但是，在实际应用中，通信装置90可以存在多个处理器或多个存储器，具体此处不做限定。此外，存储器902也可以称为存储介质或者存储设备等。存储器902可以为与处理器处于同一芯片上的存储元件(即片内存储元件)，或者为独立的存储元件，本申请实施例对此不做限定。
本实施例中，收发器903可以用于支持通信装置90与接入网设备之间射频信号的接收或者发送，收发器903可以与天线904相连。收发器903包括发射机Tx和接收机Rx。具体地，一个或多个天线904可以接收射频信号，收发器903的接收机Rx用于从天线904接收所述射频信号，并将射频信号转换为数字基带信号或数字中频信号，并将数字基带信号或数字中频信号提供给所述处理器901，以便处理器901对数字基带信号或数字中频信号做进一步的处理，例如解调处理和译码处理。此外，收发器903中的发射机Tx还用于从处理器901接收经过调制的数字基带信号或数字中频信号，并将经过调制的数字基带信号或数字中频信号转换为射频信号，并通过一个或多个天线904发送所述射频信号。具体地，接收机Rx可以选择性地对射频信号进行一级或多级下混频处理和模数转换处理以得到数字基带信号或数字中频信号，前述下混频处理和模数转换处理的先后顺序是可调整的。发射机Tx可以选择性地对经过调制的数字基带信号或数字中频信号时进行一级或多级上混频处理和数模转换处理以得到射频信号，所述上混频处理和数模转换处理的先后顺序是可调整的。数字基带信号和数字中频信号可以统称为数字信号。
应当理解的是，前述收发器903也可以称为收发单元、收发机、收发装置等。可选地，可以将收发单元中用于实现接收功能的器件视为接收单元，将收发单元中用于实现发送功能的器件视为发送单元， 即收发单元包括接收单元和发送单元，接收单元也可以称为接收机、输入口、接收电路等，发送单元可以称为发射机、发射器或者发射电路等。
处理器901可以是基带处理器，也可以是中央处理单元(central processing unit，CPU)，基带处理器和CPU可以集成在一起或者分开。处理器901可以用于为终端设备实现各种功能，例如用于对通信协议以及通信数据进行处理，或者用于对整个终端设备进行控制，执行软件程序，处理软件程序的数据；或者用于协助完成计算处理任务，例如对图形图像处理或者音频处理等等；或者处理器901用于实现上述功能中的一种或者多种。
此外，输出设备906和处理器901通信，可以以多种方式来显示信息，具体从此处不做限定。
在一种设计中，通信装置90用于执行前述图2、图3或图5对应实施例中终端设备的方法。通信装置90中的收发器903用于接收来自第一接入网设备的第一指示信息，第一指示信息用于指示第一接入网设备不能与核心网设备交互信息；处理器901在终端设备接入第一接入网设备之后，根据第一指示信息控制存储器902存储终端设备的上下文，终端设备的上下文为终端设备在第一接入网设备停止为终端设备提供服务后接入第二接入网设备使用的信息。
在一种可能的实施方式中，第二接入网设备是具有终端设备的上下文的接入网设备。
在一种可能的实施方式中，处理器901还用于在第一接入网设备停止为终端设备提供服务后，基于终端设备的上下文与第二接入网设备建立连接。
在一种可能的实施方式中，第二接入网设备与第一接入网设备是同一接入网设备。处理器901具体用于基于终端设备的上下文接入第一接入网设备的第一小区，第一小区为终端设备的上下文中存储的小区。
在一种可能的实施方式中，终端设备的上下文包括第一小区的小区标识信息。收发器903用于接收来自第一接入网设备的第一小区的小区标识信息；处理器901用于基于第一小区的小区标识信息接入第一小区。
在一种可能的实施方式中，收发器903还用于接收来自第一接入网设备的第二指示信息，第二指示信息用于指示终端设备发起接入；处理器901还用于基于第二指示信息接入第一接入网设备的第一小区。
在一种可能的实施方式中，第二接入网设备与第一接入网设备为不同的接入网设备；终端设备的上下文包括第一小区的小区标识信息。收发器903用于接收来自第二接入网设备的第一小区的小区标识信息；处理器901用于基于第一小区的小区标识信息接入第二接入网设备的第二小区。
在一种可能的实施方式中，第二接入网设备与第一接入网设备为不同的接入网设备。收发器903接收来自第二接入网设备的第三指示信息，第三指示信息用于指示终端设备发起接入；处理器901基于第三指示信息接入第二接入网设备的第二小区。
在一种可能的实施方式中，收发器903从第一接入网设备接收第一标识信息，第一标识信息用于针对第一接入网设备唯一标识终端设备。
在一种可能的实施方式中，收发器903向第一接入网设备发送终端设备的上行NAS消息；向第二接入网设备发送第一标识信息，第一标识信息用于第二接入网设备确定终端设备的上下文；以及，从第二接入网设备接收终端设备的下行NAS消息。
在一种可能的实施方式中，处理器901具体用于：在发送上行NAS消息时启动第一NAS定时器，第一NAS定时器为接入网设备不能与核心网设备交互信息时使用的NAS定时器；或者，在发送上行NAS消息之后的第一时长之后启动第二NAS定时器，第二NAS定时器为接入网设备能够与核心网设备交互信息时使用的NAS定时器。
在一种可能的实施方式中，收发器903还用于接收来自第一接入网设备的第一时间信息，第一时间信息用于确定第一NAS定时器的时长或者第一时长。
在另一种设计中，通信装置90用于执行前述图7对应实施例中终端设备的方法。通信装置90中的收发器903用于从第三接入网设备接收寻呼消息。或者，通信装置90中的收发器903用于从第四接入网设备接收寻呼消息。
在另一种设计中，通信装置90用于执行前述图8对应实施例中终端设备的方法。通信装置90中的收发器903用于从第五接入网设备接收携带第一序列号或第二序列号的数据包，以及，向第五接入网设备发送接收的数据包的表示确认接收的指示(例如，确认字符(acknowledge character，ACK))。此外，该收发器903还将向第六接入网设备发送第七指示信息，第七指示信息用于指示终端设备已连续成功接收的数据包。可选的，第七指示信息包括目标序列号，目标序列号为终端设备已连续确认接收的最后一个数据包的序列号。
需要说明的是，本实施例的具体实施方式和有益效果可参考上述实施例中终端设备的方法，此处不再赘述。
如图10所示，为本实施例提供的另一种通信装置100的结构示意图。应当理解的是，前述图2、图3、图5、图7或图8对应的方法实施例中的接入网设备可以基于本实施例中图10所示的通信装置100的结构。例如，图2、图3或图5对应的方法实施例中的第一接入网设备或第二接入网设备；或者，图7对应的方法实施例中的第三接入网设备或第四接入网设备；或者，图8对应的方法实施例中的第五接入网设备或第六接入网设备。
通信装置100包括至少一个处理器1001、至少一个存储器1002、至少一个收发器1003、至少一个网络接口1005和一个或多个天线1004。处理器1001、存储器1002、收发器1003和网络接口1005通过连接装置相连，天线1004与收发器1003相连。其中，前述连接装置可包括各类接口、传输线或总线等，本实施例对此不做限定。
其中，存储器1002主要用于存储软件程序和数据。存储器1002可以是独立存在，与处理器1001相连。可选地，存储器1002可以和处理器1001集成于一体，例如集成于一个或多个芯片之内。其中，存储器1002能够存储执行本申请实施例的技术方案的程序代码，并由处理器1001来控制执行，被执行的各类计算机程序代码也可被视为是处理器1001的驱动程序。应当理解的是，本实施例中的图10仅示出了一个存储器和一个处理器，但是，在实际应用中，通信装置100可以存在多个处理器或多个存储器，具体此处不做限定。此外，存储器1002也可以称为存储介质或者存储设备等。存储器1002可以为与处理器处于同一芯片上的存储元件(即片内存储元件)，或者为独立的存储元件，本申请实施例对此不做限定。
本实施例中，收发器1003可以用于支持通信装置100与终端设备之间射频信号的接收或者发送，收发器1003可以与天线1004相连。收发器1003包括发射机Tx和接收机Rx。具体地，一个或多个天线1004可以接收射频信号，收发器1003的接收机Rx用于从天线1004接收所述射频信号，并将射频信号转换为数字基带信号或数字中频信号，并将数字基带信号或数字中频信号提供给所述处理器1001，以便处理器1001对数字基带信号或数字中频信号做进一步的处理，例如解调处理和译码处理。此外，收发器1003中的发射机Tx还用于从处理器1001接收经过调制的数字基带信号或数字中频信号，并将经过调制的数字基带信号或数字中频信号转换为射频信号，并通过一个或多个天线1004发送所述射频信号。具体地，接收机Rx可以选择性地对射频信号进行一级或多级下混频处理和模数转换处理以得到数字基带信号或数字中频信号，前述下混频处理和模数转换处理的先后顺序是可调整的。发射机Tx可以选择性地对经过调制的数字基带信号或数字中频信号时进行一级或多级上混频处理和数模转换处理以得到射频信号，所述上混频处理和数模转换处理的先后顺序是可调整的。数字基带信号和数字中频信号可以统称为数字信号。
应当理解的是，前述收发器1003也可以称为收发单元、收发机、收发装置等。可选地，可以将收发单元中用于实现接收功能的器件视为接收单元，将收发单元中用于实现发送功能的器件视为发送单元，即收发单元包括接收单元和发送单元，接收单元也可以称为接收机、输入口、接收电路等，发送单元可以称为发射机、发射器或者发射电路等。
此外，前述处理器1001主要用于对通信协议以及通信数据进行处理，以及对整个网络设备进行控制，执行软件程序，处理软件程序的数据，例如用于支持通信装置100执行前述实施例中所描述的动作。通信装置100可以包括基带处理器和中央处理器，其中，基带处理器主要用于对通信协议以及通信数据进行处理，中央处理器主要用于对整个通信装置100进行控制，执行软件程序，处理软件程序的数据。如图10中的处理器1001可以集成基带处理器和中央处理器的功能，本领域技术人员可以理解，基带处理器 和中央处理器也可以是各自独立的处理器，通过总线等技术互联。本领域技术人员可以理解，通信装置100可以包括多个基带处理器以适应不同的网络制式，通信装置100可以包括多个中央处理器以增强其处理能力，通信装置100的各个部件可以通过各种总线连接。所述基带处理器也可以表述为基带处理电路或者基带处理芯片。所述中央处理器也可以表述为中央处理电路或者中央处理芯片。对通信协议以及通信数据进行处理的功能可以内置在处理器中，也可以以软件程序的形式存储在存储器中，由处理器执行软件程序以实现基带处理功能。
此外，前述网络接口1005用于使通信装置100通过通信链路，与其它通信装置相连。具体地，网络接口1005可以包括通信装置100与核心网网元之间的网络接口，例如S1接口；网络接口1005也可以包括通信装置100和其他网络设备(例如其他接入网设备或者核心网网元)之间的网络接口，例如X2或者Xn接口。
在一种设计中，通信装置100用于执行前述图2、图3或图5对应实施例中第一接入网设备的方法。通信装置100中的收发器1003用于广播第一指示信息，第一指示信息用于指示第一接入网设备不能与核心网设备交互信息；处理器1001用于与终端设备建立连接；存储器1002用在第一接入网设备与终端设备建立连接之后，存储终端设备的上下文，该终端设备的上下文为该第一接入网设备停止为该终端设备提供服务后，第二接入网设备接纳该终端设备使用的信息。
在一种可能的实施方式中，收发器1003用于在第一区域广播第一指示信息，第一区域为接入网设备不能与核心网设备建立连接的区域。
在一种可能的实施方式中，收发器1003用于在第一区域接收来自终端设备的上行NAS消息；处理器1001还用于当第一接入网设备移动至第二区域时，控制收发器1003向核心网设备发送上行NAS消息，第二区域为接入网设备能够与核心网设备建立连接的区域。
在一种可能的实施方式中，第二接入网设备为第一接入网设备。当第一接入网设备再次移动至第一区域时，处理器1001基于终端设备的上下文与终端设备建立连接。
在一种可能的实施方式中，处理器1001用于基于终端设备的上下文通过第一接入网设备的第一小区为终端设备提供服务，第一小区为第一接入网设备存储终端设备的上下文时终端设备接入的小区。
在一种可能的实施方式中，收发器1003用于在第一区域广播第一小区的小区标识信息，第一小区的小区标识信息用于终端设备接入第一小区。
在一种可能的实施方式中，收发器1003用于在第一小区向终端设备发送第二指示信息，第二指示信息用于指示终端设备基于终端设备的上下文发起接入。
在一种可能的实施方式中，收发器1003用于在第二区域从核心网设备接收终端设备的下行NAS消息；以及，向终端设备发送下行NAS消息。
在一种可能的实施方式中，收发器1003用于向终端设备发送第一标识信息，第一标识信息用于针对第一接入网设备唯一标识终端设备；以及，从终端设备接收第一标识信息。处理器1001用于基于终端设备的第一标识信息确定终端设备的上下文；以及，基于终端设备的上下文确定下行NAS消息。
在一种可能的实施方式中，终端设备的上下文包括终端设备的地理区域信息；处理器1001用于基于终端设备的小区无线网络临时标识和终端设备的地理区域信息确定终端设备的上下文；以及，基于终端设备的上下文确定下行NAS消息。
在一种可能的实施方式中，终端设备的上下文包括终端设备接入第一接入网设备的时间信息。处理器1001用于基于终端设备的小区无线网络临时标识和终端设备接入第一接入网设备的时间信息确定终端设备的上下文；以及，基于终端设备的上下文确定下行NAS消息。
在一种可能的实施方式中，第二接入网设备与第一接入网设备为不同的接入网设备。处理器1001用于当第一接入网设备移动至第二区域时控制收发器1003向核心网设备发送终端设备的上下文，第二区域为接入网设备能够与核心网设备建立连接的区域，终端设备的上下文用于核心网设备确定的第二接入网设备与终端设备建立连接。
在一种可能的实施方式中，收发器1003用于在第一区域广播第一时间信息，第一时间信息用于确定第一NAS定时器。
在一种可能的实施方式中，处理器1001用于当第一接入网设备移动至第二区域时，控制收发器1003向核心网设备发送第四指示信息，第四指示信息用于指示终端设备在第一接入网设备不能与核心网设备建立连接时接入到第一接入网设备。
在一种可能的实施方式中，处理器1001用于当第一接入网设备移动至第二区域时，控制收发器1003向核心网设备发送第一时间信息，第一时间信息用于确定核心网设备的第一NAS定时器。
在另一种设计中，通信装置100用于执行前述图2、图3或图5对应实施例中第二接入网设备的方法。收发器1003用于从核心网设备接收终端设备的上下文和终端设备的下行NAS消息；处理器1001用于基于终端设备的上下文确定终端设备所在的地理区域；处理器1001还用于当第二接入网设备移动至终端设备所在的地理区域时，控制收发器1003向终端设备发送第二指示信息，第二指示信息用于指示终端设备发起随机接入；以及在终端设备接入之后，控制收发器1003向终端设备发送终端设备的下行NAS消息。
在一种可能的实施方式中，收发器1003用于从终端设备接收第一标识信息，第一标识信息用于针对第一接入网设备唯一标识终端设备。处理器1001用于基于第一标识信息确定终端设备的上下文；以及，基于终端设备的上下文确定下行NAS消息。
在一种可能的实施方式中，终端设备的上下文包括终端设备的地理区域信息。处理器1001用于基于终端设备的小区无线网络临时标识和终端设备的地理区域信息确定终端设备的上下文；以及，基于终端设备的上下文确定下行NAS消息。
在一种可能的实施方式中，终端设备的上下文包括终端设备接入第一接入网设备的时间信息。处理器1001基于终端设备的小区无线网络临时标识和终端设备接入第一接入网设备的时间信息确定终端设备的上下文；以及，基于终端设备的上下文确定下行NAS消息。
在另一种设计中，通信装置100用于执行前述图7对应实施例中第三接入网设备的方法。通信装置100中的收发器1003用于接收寻呼消息，寻呼消息包括终端设备的地理区域信息；处理器1001用于当第三接入网设备移动至终端设备所在的地理区域时，控制收发器1003在终端设备所在的地理区域广播寻呼消息。
在一种可能的实施方式中，收发器1003用于向第四接入网设备发送第五指示信息，第四接入网设备为在第三接入网设备停止为终端设备提供服务后为终端设备提供服务的接入网设备，第五指示信息用于指示第四接入网设备删除用于寻呼终端设备的寻呼消息。
在另一种设计中，通信装置100用于执行前述图7对应实施例中第四接入网设备的方法。收发器1003用于从第三接入网设备接收第五指示信息，第五指示信息用于指示第四接入网设备删除用于寻呼终端设备的寻呼消息。
在另一种设计中，通信装置100用于执行前述图8对应实施例中第五接入网设备的方法。通信装置100中的收发器1003用从核心网设备接收终端设备的多个数据包，每个数据包对应一个第一序列号；处理器1001用于当第五接入网设备移动至终端设备所在的地理区域时，基于第一序列号控制收发器1003向终端设备发送携带第一序列号的数据包；或者，当第五接入网设备移动至终端设备所在的地理区域时，基于每个数据包的第一序列号和第一映射规则确定每个数据包的第二序列号，以及，基于第二序列号控制收发器1003向终端设备发送携带第二序列号的数据包。
在一种可能的实施方式中，处理器1001用于在停止为终端设备提供服务之前，控制收发器1003向终端设备发送第六指示信息，第六指示信息用于指示存在待发送的数据包。
在另一种设计中，通信装置100用于执行前述图8对应实施例中第六接入网设备的方法。收发器1003用于从核心网设备接收终端设备的多个数据包和终端设备的上下文，每个数据包对应一个第一序列号；处理器1001用于基于终端设备的上下文与终端设备建立连接；收发器1003从终端设备接收第七指示信息，第七指示信息用于指示终端设备已连续成功接收的数据包；以及，基于第七指示信息向终端设备发送多个数据包中的至少一个数据包。
在一种可能的实施方式中，第七指示信息包括目标序列号，目标序列号为终端设备已连续确认接收的最后一个数据包的序列号。
在一种可能的实施方式中，目标序列号为第一序列号。收发器1003用于向终端设备发送携带第一序列号的至少一个数据包，至少一个数据包中每个数据包的第一序列号大于目标序列号。
在一种可能的实施方式中，目标序列号为第二序列号。处理器1001用于基于每个数据包的第一序列号和第一映射规则确定每个数据包的第二序列号；收发器1003用于向终端设备发送携带第二序列号的至少一个数据包，至少一个数据包中每个数据包的第二序列号大于目标序列号。
需要说明的是，本实施例的具体实施方式和有益效果可参考上述实施例中接入网设备的方法，此处不再赘述。
如图11所示，为本实施例提供的另一种通信装置110的结构示意图。应当理解的是，前述图2、图3、图5、图7或图8对应的方法实施例中的核心网设备可以基于本实施例中图11所示的通信装置110的结构。如图11所示，该通信装置110可以包括处理器1101、存储器1103和通信接口1102。其中，该处理器1101与该存储器1103耦合连接，该处理器1101与该通信接口1102耦合连接。
其中，前述通信接口1102通过通信链路，与其它通信装置相连。例如，通信接口1102可以包括通信装置100与接入网设备(例如，图9所示的通信装置90)之间的网络接口，例如S1接口。
其中，前述处理器1101可以是中央处理器(central processing unit，CPU)、专用集成电路(application-specific integrated circuit，ASIC)、可编程逻辑器件(programmable logic device，PLD)或其组合。上述PLD可以是复杂可编程逻辑器件(complex programmable logic device，CPLD)，现场可编程逻辑门阵列(field-programmable gate array，FPGA)，通用阵列逻辑(generic array logic，GAL)或其任意组合。处理器1101可以是指一个处理器，也可以包括多个处理器，具体此处不做限定。
此外，前述该存储器1103主要用于存储软件程序和数据。存储器1103可以是独立存在，与处理器1101相连。可选地，该存储器1103可以和该处理器1101集成于一体，例如集成于一个或多个芯片之内。其中，该存储器1103能够存储执行本申请实施例的技术方案的程序代码，并由处理器1101来控制执行，被执行的各类计算机程序代码也可被视为是处理器1101的驱动程序。存储器1103可以包括易失性存储器(volatile memory)，例如随机存取存储器(random-access memory，RAM)；存储器也可以包括非易失性存储器(non-volatile memory)，例如只读存储器(read-only memory，ROM)，快闪存储器(flash memory)，硬盘(hard disk drive，HDD)或固态硬盘(solid-state drive，SSD)；存储器1103还可以包括上述种类的存储器的组合。存储器1103可以是指一个存储器，也可以包括多个存储器。示例性的，存储器1103，用于存储各种数据。例如，第一参考位置、第一距离门限。此外，该存储器1103还用于存储第一规则信息、第二规则信息、第三规则信息以及第四规则信息等。具体地，请参阅前文实施例中的相关介绍，此处不予赘述。
在一种设计中，通信装置110用于执行前述图2、图3或图5对应实施例中核心网设备的方法。其中，通信接口1102用于从第一接入网设备接收终端设备的上行NAS消息和第四指示信息，该第四指示信息用于指示该终端设备在该第一接入网设备不能与该核心网设备交互信息时接入到该第一接入网设备；处理器1101用于基于该第四指示信息生效第一NAS定时器。
在一种可能的实施方式中，通信接口1102用于从该第一接入网设备接收第一时间信息，该第一时间信息用于确定核心网设备的第一NAS定时器。
在一种可能的实施方式中，通信接口1102用于向该第一接入网设备发送该终端设备的下行NAS消息，并且，该核心网设备启动该第一NAS定时器；处理器1101在该第一NAS定时器超时之前，通过通信接口1102从该第一接入网设备接收该下行NAS消息对应的上行NAS消息。
在一种可能的实施方式中，处理器1101在该第一NAS定时器超时之前通过通信接口1102向第二接入网设备发送该终端设备的下行NAS消息，并且，该核心网设备启动该第一NAS定时器，该第二接入网设备为移动至该终端设备所在的地理区域的接入网设备；处理器1101在该第一NAS定时器超时之前，通过通信接口1102接收该下行NAS消息对应的上行NAS消息。
在一种可能的实施方式中，通信接口1102用于从该第一接入网设备接收该终端设备的上下文；处理器1101用于基于该终端设备的上下文确定该第二接入网设备；通信接口1102还用于在向该第二接入 网设备发送该终端设备的上下文。
在一种设计中，通信装置110用于执行前述图7对应实施例中核心网设备的方法。其中，处理器1101用于根据终端设备的地理区域信息确定至少一个接入网设备，该接入网设备当前的覆盖区域不包括该终端设备所在的地理区域，该接入网设备的覆盖区域的移动路径经过该终端设备所在的地理区域；通信接口1102用于向该至少一个接入网设备发送寻呼消息，该寻呼消息包括该终端设备的地理区域信息。
在一种可能的实施方式中，通信接口1102用于在发送该寻呼消息时，该核心网设备启动第一寻呼定时器，该第一寻呼定时器的时长大于预配置的寻呼定时器的时长。
在一种设计中，通信装置110用于执行前述图8对应实施例中核心网设备的方法。其中，处理器1101用于确定终端设备的多个数据包以及每个数据包对应的第一序列号。通信接口1102用于发送终端设备的多个数据包，每个该数据包对应一个第一序列号；通信接口1102还用于向第六接入网设备发送该终端设备的上下文和该终端设备的多个数据包，该第六接入网设备为在该第五接入网设备停止为该终端设备提供服务后为该终端设备提供服务的接入网设备，该终端设备的上下文用于该第六接入网设备与该终端设备建立连接并向该终端设备发送该终端设备的多个数据包。
需要说明的是，本实施例的具体实施方式和有益效果可参考上述实施例中核心网设备的方法，此处不再赘述。
如图12所示，本申请还提供了一种通信装置120。该通信装置120可以是终端设备、接入网设备或核心网设备，也可以是终端设备、接入网设备或核心网设备的部件(例如，集成电路、芯片等)。该通信装置120也可以是其他用于实现本申请方法实施例中的方法的通信模块。
该通信装置120可以包括处理模块1201(或称为处理单元)。可选的，还可以包括接口模块1202(或称为收发单元或收发模块)和存储模块1203(或称为存储单元)。接口模块1202用于实现与其他设备进行通信。接口模块1202例如可以是收发模块或输入输出模块。
在一种可能的设计中，如图12中的一个或者多个模块可能由一个或者多个处理器来实现，或者由一个或者多个处理器和存储器来实现；或者由一个或多个处理器和收发器实现；或者由一个或者多个处理器、存储器和收发器实现，本申请实施例对此不作限定。所述处理器、存储器、收发器可以单独设置，也可以集成于一体。
该通信装置120具备实现本申请实施例描述的终端设备的功能。例如，通信装置120包括终端设备执行本申请实施例描述的终端设备涉及步骤所对应的模块或单元或手段(means)，所述功能或单元或手段(means)可以通过软件实现，或者通过硬件实现，也可以通过硬件执行相应的软件实现，还可以通过软件和硬件结合的方式实现。详细可进一步参考前述对应方法实施例中的相应描述。具体请参阅前文图9对应实施例中的通信装置90。
或者，通信装置120具备实现本申请实施例描述的接入网设备的功能。例如，所述通信装置120包括接入网设备执行本申请实施例描述的接入网设备涉及步骤所对应的模块或单元或手段(means)，所述功能或单元或手段(means)可以通过软件实现，或者通过硬件实现，也可以通过硬件执行相应的软件实现，还可以通过软件和硬件结合的方式实现。详细可进一步参考前述对应方法实施例中的相应描述。具体请参阅前文图10对应实施例中的通信装置100。
或者，通信装置120具备实现本申请实施例描述的核心网设备的功能。例如，所述通信装置120包括核心网设备执行本申请实施例描述的核心网设备涉及步骤所对应的模块或单元或手段(means)，所述功能或单元或手段(means)可以通过软件实现，或者通过硬件实现，也可以通过硬件执行相应的软件实现，还可以通过软件和硬件结合的方式实现。详细可进一步参考前述对应方法实施例中的相应描述。具体请参阅前文图11对应实施例中的通信装置110。
此外，本申请提供了一种计算机程序产品，该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该计算机程序指令时，全部或部分地产生按照本申请实施例该的流程或功能。例如，实现如前述图2、图3、图5、图7或图8中的接入网设备相关的方法。又例如，实现如前述图2、图3、图5、图7或图8中的终端设备相关的方法。又例如，实现如前述图2、图3、图5、图7或图8中的核心网设备相 关的方法。该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。该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，该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。该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。该可用介质可以是磁性介质，(例如，软盘、硬盘、磁带)、光介质(例如，数字通用光盘(digital versatile disc，DVD))、或者半导体介质(例如固态硬盘(solid state disk，SSD))等。
此外，本申请还提供了一种计算机可读存储介质，该存储介质存储有计算机程序，该计算机程序被处理器执行以实现如前述图2、图3、图5、图7或图8中的接入网设备相关的方法。
此外，本申请还提供了一种计算机可读存储介质，该存储介质存储有计算机程序，该计算机程序被处理器执行以实现如前述图2、图3、图5、图7或图8中的终端设备相关的方法。
此外，本申请还提供了一种计算机可读存储介质，该存储介质存储有计算机程序，该计算机程序被处理器执行以实现如前述图2、图3、图5、图7或图8中的核心网设备相关的方法。
应理解，在本申请的各种实施例中，上述各过程的序号的大小并不意味着执行顺序的先后，各过程的执行顺序应以其功能和内在逻辑确定，而不应对本申请实施例的实施过程构成任何限定。
所属领域的技术人员可以清楚地了解到，为描述的方便和简洁，上述描述的系统，装置和单元的具体工作过程，可以参考前述方法实施例中的对应过程，在此不再赘述。

Claims (42)

  1. 一种通信方法，其特征在于，包括：
    终端设备接收来自第一接入网设备的第一指示信息，所述第一指示信息用于指示所述第一接入网设备不能与核心网设备交互信息；
    在所述终端设备接入所述第一接入网设备之后，所述终端设备根据所述第一指示信息存储所述终端设备的上下文，所述终端设备的上下文为所述终端设备在所述第一接入网设备停止为所述终端设备提供服务后接入第二接入网设备使用的信息。
  2. 根据权利要求1所述的方法，其特征在于，所述第二接入网设备是具有所述终端设备的上下文的接入网设备。
  3. 根据权利要求1或2所述的方法，其特征在于，所述终端设备根据所述第一指示信息存储所述终端设备的上下文之后，所述方法还包括：
    在所述第一接入网设备停止为所述终端设备提供服务后，所述终端设备基于所述终端设备的上下文与所述第二接入网设备建立连接。
  4. 根据权利要求3所述的方法，其特征在于，所述第二接入网设备与所述第一接入网设备是同一接入网设备；
    所述终端设备基于所述终端设备的上下文与所述第二接入网设备进行连接，包括：
    所述终端设备基于所述终端设备的上下文接入所述第一接入网设备的第一小区，所述第一小区为所述终端设备的上下文中存储的小区。
  5. 根据权利要求4所述的方法，其特征在于，所述终端设备的上下文包括所述第一小区的小区标识信息；
    所述终端设备基于所述终端设备的上下文接入所述第一接入网设备的第一小区，包括：
    若所述终端设备接收到来自所述第一接入网设备的所述第一小区的小区标识信息，则所述终端设备基于所述第一小区的小区标识信息接入所述第一小区。
  6. 根据权利要求4所述的方法，其特征在于，所述终端设备基于所述终端设备的上下文接入所述第一接入网设备的第一小区，包括：
    所述终端设备接收来自所述第一接入网设备的第二指示信息，所述第二指示信息用于指示所述终端设备发起接入；
    所述终端设备基于所述第二指示信息接入所述第一接入网设备的所述第一小区。
  7. 根据权利要求3所述的方法，其特征在于，所述第二接入网设备与所述第一接入网设备为不同的接入网设备；所述终端设备的上下文包括第一小区的小区标识信息；
    所述终端设备基于所述终端设备的上下文与所述第二接入网设备建立连接，包括：
    若所述终端设备接收到来自所述第二接入网设备的所述第一小区的小区标识信息，则所述终端设备基于所述第一小区的小区标识信息接入所述第二接入网设备的第二小区。
  8. 根据权利要求3所述的方法，其特征在于，所述第二接入网设备与所述第一接入网设备为不同的接入网设备；
    所述终端设备基于所述终端设备的上下文与所述第二接入网设备建立连接，包括：
    所述终端设备接收来自所述第二接入网设备的第三指示信息，所述第三指示信息用于指示所述终端设备发起接入；
    所述终端设备基于所述第三指示信息接入所述第二接入网设备的第二小区。
  9. 根据权利要求3至8中任意一项所述的方法，其特征在于，所述方法还包括：
    所述终端设备从所述第一接入网设备接收第一标识信息，所述第一标识信息用于针对所述第一接入网设备唯一标识所述终端设备。
  10. 根据权利要求9所述的方法，其特征在于，所述第一接入网设备停止为所述终端设备提供服务之前，所述方法还包括：
    所述终端设备向所述第一接入网设备发送所述终端设备的上行NAS消息；
    所述终端设备基于所述终端设备的上下文与所述第二接入网设备建立连接之后，所述方法还包括：
    所述终端设备向所述第二接入网设备发送所述第一标识信息，所述第一标识信息用于所述第二接入网设备确定所述终端设备的上下文；
    所述终端设备从所述第二接入网设备接收所述终端设备的下行NAS消息。
  11. 根据权利要求1至10中任意一项所述的方法，其特征在于，所述第一接入网设备停止为所述终端设备提供服务之前，所述方法还包括：
    所述终端设备在发送上行NAS消息时启动第一NAS定时器，所述第一NAS定时器为接入网设备不能与核心网设备交互信息时使用的NAS定时器；
    或者，
    所述终端设备在发送上行NAS消息之后的第一时长之后启动第二NAS定时器，所述第二NAS定时器为接入网设备能够与核心网设备交互信息时使用的NAS定时器。
  12. 根据权利要求11所述的方法，其特征在于，所述方法还包括：
    所述终端设备接收来自所述第一接入网设备的第一时间信息，所述第一时间信息用于确定所述第一NAS定时器的时长或者所述第一时长。
  13. 一种通信方法，其特征在于，包括：
    第一接入网设备广播第一指示信息，所述第一指示信息用于指示所述第一接入网设备不能与核心网设备交互信息；
    当所述第一接入网设备与终端设备建立连接之后，所述第一接入网设备存储所述终端设备的上下文，所述终端设备的上下文为所述第一接入网设备停止为所述终端设备提供服务后，第二接入网设备接纳所述终端设备使用的信息。
  14. 根据权利要求13所述的方法，其特征在于，所述第一接入网设备广播第一指示信息，包括：
    所述第一接入网设备在第一区域广播所述第一指示信息，所述第一区域为接入网设备不能与核心网设备建立连接的区域。
  15. 根据权利要求14所述的方法，其特征在于，
    所述第一接入网设备停止为所述终端设备提供服务之前，所述方法还包括：
    所述第一接入网设备在所述第一区域接收来自所述终端设备的上行NAS消息；
    所述第一接入网设备存储所述终端设备的上下文之后，所述方法还包括：
    当所述第一接入网设备移动至第二区域时，所述第一接入网设备向所述核心网设备发送所述上行NAS消息，所述第二区域为接入网设备能够与所述核心网设备建立连接的区域。
  16. 根据权利要求15所述的方法，其特征在于，所述第二接入网设备与所述第一接入网设备是同一接入网设备；
    所述方法还包括：
    当所述第一接入网设备再次移动至所述第一区域时，所述第一接入网设备基于所述终端设备的上下文与所述终端设备建立连接。
  17. 根据权利要求16所述的方法，其特征在于，所述第一接入网设备基于所述终端设备的上下文与所述终端设备建立连接，包括：
    所述第一接入网设备基于所述终端设备的上下文通过所述第一接入网设备的第一小区为所述终端设备提供服务，所述第一小区为所述第一接入网设备存储所述终端设备的上下文时所述终端设备接入的小区。
  18. 根据权利要求17所述的方法，其特征在于，所述第一接入网设备基于所述终端设备的上下文与所述终端设备建立连接之前，所述方法还包括：
    所述第一接入网设备在所述第一小区向所述终端设备发送第二指示信息，所述第二指示信息用于指示所述终端设备发起接入。
  19. 根据权利要求15至18中任意一项所述的方法，其特征在于，所述第一接入网设备向所述核心网设备发送所述上行NAS消息之后，所述方法还包括：
    所述第一接入网设备在所述第二区域从所述核心网设备接收所述终端设备的下行NAS消息；
    所述第一接入网设备基于所述终端设备的上下文与所述终端设备建立连接之后，所述方法还包括：
    所述第一接入网设备向所述终端设备发送所述下行NAS消息。
  20. 根据权利要求19所述的方法，其特征在于，所述第一接入网设备在所述第一区域接收来自所述终端设备的上行NAS消息之前，所述方法还包括：
    所述第一接入网设备向所述终端设备发送第一标识信息，所述第一标识信息用于针对所述第一接入网设备唯一标识所述终端设备；
    所述第一接入网设备向所述终端设备发送所述下行NAS消息之前，所述方法还包括：
    所述第一接入网设备从所述终端设备接收所述第一标识信息；
    所述第一接入网设备基于所述第一标识信息确定所述终端设备的上下文；
    所述第一接入网设备基于所述终端设备的上下文确定所述下行NAS消息。
  21. 根据权利要求19所述的方法，其特征在于，所述终端设备的上下文包括所述终端设备的地理区域信息；
    所述第一接入网设备向所述终端设备发送所述下行NAS消息之前，所述方法还包括：
    所述第一接入网设备基于所述终端设备的小区无线网络临时标识和所述终端设备的地理区域信息确定所述终端设备的上下文；
    所述第一接入网设备基于所述终端设备的上下文确定所述下行NAS消息。
  22. 根据权利要求19所述的方法，其特征在于，所述终端设备的上下文包括所述终端设备接入所述第一接入网设备的时间信息；
    所述第一接入网设备向所述终端设备发送所述下行NAS消息之前，所述方法还包括：
    所述第一接入网设备基于所述终端设备的小区无线网络临时标识和所述终端设备接入所述第一接入网设备的时间信息确定所述终端设备的上下文；
    所述第一接入网设备基于所述终端设备的上下文确定所述下行NAS消息。
  23. 根据权利要求13或14所述的方法，其特征在于，所述第二接入网设备与所述第一接入网设备为不同的接入网设备；
    所述第一接入网设备存储所述终端设备的上下文之后，所述方法还包括：
    当所述第一接入网设备移动至第二区域时，所述第一接入网设备向所述核心网设备发送所述终端设备的上下文，所述第二区域为接入网设备能够与所述核心网设备建立连接的区域，所述终端设备的上下文用于所述核心网设备确定的第二接入网设备与所述终端设备建立连接。
  24. 根据权利要求14至23中任意一项所述的方法，其特征在于，所述第一接入网设备在第一区域接收来自终端设备的上行NAS消息之前，所述方法还包括：
    所述第一接入网设备在所述第一区域广播第一时间信息，所述第一时间信息用于确定终端设备的第一NAS定时器。
  25. 根据权利要求15至24中任意一项所述的方法，其特征在于，所述方法还包括：
    当所述第一接入网设备移动至第二区域时，所述第一接入网设备向所述核心网设备发送第四指示信息，所述第四指示信息用于指示所述终端设备是在所述第一接入网设备不能与所述核心网设备建立连接时接入到所述第一接入网设备。
  26. 根据权利要求15至25中任意一项所述的方法，其特征在于，所述方法还包括：
    当所述第一接入网设备移动至第二区域时，所述第一接入网设备向所述核心网设备发送第一时间信息，所述第一时间信息用于确定核心网设备的第一NAS定时器。
  27. 一种通信方法，其特征在于，包括：
    核心网设备从第一接入网设备接收终端设备的上行NAS消息和第四指示信息，所述第四指示信息用于指示所述终端设备在所述第一接入网设备不能与所述核心网设备建立连接时接入到所述第一接入网设备，所述第四指示信息还用于所述核心网设备在发送下行NAS消息时启动第一NAS定时器。
  28. 根据权利要求27所述的方法，其特征在于，所述方法还包括：
    所述核心网设备从所述第一接入网设备接收第一时间信息，所述第一时间信息用于确定所述第一NAS定时器。
  29. 根据权利要求27或28所述的方法，其特征在于，所述方法还包括：
    所述核心网设备向所述第一接入网设备发送所述终端设备的下行NAS消息，并且，所述核心网设备启动所述第一NAS定时器；
    在所述第一NAS定时器超时之前，所述核心网设备从所述第一接入网设备接收所述下行NAS消息对应的上行NAS消息。
  30. 根据权利要求27或28所述的方法，其特征在于，所述方法还包括：
    所述核心网设备向第二接入网设备发送所述终端设备的下行NAS消息，并且，所述核心网设备启动所述第一NAS定时器，所述第二接入网设备为即将移动至所述终端设备所在的地理区域的接入网设备；
    在所述第一NAS定时器超时之前，所述核心网设备接收所述下行NAS消息对应的上行NAS消息。
  31. 根据权利要求30所述的方法，其特征在于，所述方法还包括：
    所述核心网设备从所述第一接入网设备接收所述终端设备的上下文；
    所述核心网设备在向所述第二接入网设备发送所述终端设备的上下文。
  32. 一种通信方法，其特征在于，包括：
    第二接入网设备从核心网设备接收终端设备的上下文和所述终端设备的下行NAS消息；
    所述第二接入网设备基于所述终端设备的上下文确定所述终端设备所在的地理区域；
    当所述第二接入网设备移动至所述终端设备所在的地理区域时，所述第二接入网设备向所述终端设备发送第二指示信息，所述第二指示信息用于指示所述终端设备发起随机接入；
    所述第二接入网设备在所述终端设备接入之后，向所述终端设备发送所述终端设备的下行NAS消息。
  33. 根据权利要求32所述的方法，其特征在于，向所述终端设备发送所述终端设备的下行NAS消息之前，所述方法还包括：
    所述第二接入网设备从所述终端设备接收第一标识信息，所述第一标识信息用于在所述第一接入网设备中唯一标识所述终端设备；
    所述第二接入网设备基于所述第一标识信息确定所述终端设备的上下文；
    所述第二接入网设备基于所述终端设备的上下文确定所述下行NAS消息。
  34. 根据权利要求33所述的方法，其特征在于，所述终端设备的上下文包括所述终端设备的地理区域信息；
    所述第二接入网设备向所述终端设备发送所述下行NAS消息之前，所述方法还包括：
    所述第二接入网设备基于所述终端设备的小区无线网络临时标识和所述终端设备的地理区域信息确定所述终端设备的上下文；
    所述第二接入网设备基于所述终端设备的上下文确定所述下行NAS消息。
  35. 根据权利要求33所述的方法，其特征在于，所述终端设备的上下文包括所述终端设备接入第一接入网设备的时间信息；
    所述第二接入网设备向所述终端设备发送所述下行NAS消息之前，所述方法还包括：
    所述第二接入网设备基于所述终端设备的小区无线网络临时标识和所述终端设备接入所述第一接入网设备的时间信息确定所述终端设备的上下文；
    所述第二接入网设备基于所述终端设备的上下文确定所述下行NAS消息。
  36. 一种通信方法，其特征在于，包括：
    终端设备从第五接入网设备接收至少一个数据包，每个所述数据包对应一个第一序列号或第二序列号；
    在所述第五接入网设备停止为所述终端设备提供服务之后，所述终端设备与第六接入网设备建立连接；
    所述终端设备向所述第六接入网设备发送第七指示信息，所述第七指示信息用于指示所述终端设备已连续成功接收的数据包；
    所述终端设备从所述第六接入网设备接收至少一个数据包。
  37. 根据权利要求36所述的方法，其特征在于，所述第七指示信息包括目标序列号，所述目标序列号为所述终端设备已连续确认接收的最后一个数据包的序列号。
  38. 根据权利要求37所述的方法，其特征在于，在所述第五接入网设备停止为所述终端设备提供服务之前，所述方法还包括：
    所述终端设备从所述第五接入网设备接收第六指示信息，所述第六指示信息用于指示存在待发送的数据包。
  39. 一种通信装置，其特征在于，包括处理器和存储器；
    其中，存储器存储有计算机程序；
    所述处理器调用所述计算机程序以使得所述通信装置执行如权利要求1至12中任意一项所述的方法；或者，执行如权利要求36至38中任意一项所述的方法。
  40. 一种通信装置，其特征在于，包括处理器和存储器；
    其中，存储器存储有计算机程序；
    所述处理器调用所述计算机程序以使得所述通信装置执行如权利要求13至26中任意一项所述的方法；或者，执行如权利要求32至35中任意一项所述的方法。
  41. 一种通信装置，其特征在于，包括处理器和存储器；
    其中，存储器存储有计算机程序；
    所述处理器调用所述计算机程序以使得所述通信装置执行如权利要求27至31中任意一项所述的方法。
  42. 一种计算机可读存储介质，存储有指令，当所述指令在计算机上运行时，使得计算机执行如权利要求1至12中任意一项所述的方法；或者，执行如权利要求13至26中任意一项所述的方法；或者，执行如权利要求27至31中任意一项所述的方法；或者，执行如权利要求32至35中任意一项所述的方法；或者，执行如权利要求36至38中任意一项所述的方法。
PCT/CN2023/119407 2022-09-30 2023-09-18 一种通信方法、通信装置及系统 WO2024067206A1 (zh)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CN202211215589.8A CN117858197A (zh) 2022-09-30 2022-09-30 一种通信方法、通信装置及系统
CN202211215589.8 2022-09-30

Publications (1)

Publication Number Publication Date
WO2024067206A1 true WO2024067206A1 (zh) 2024-04-04

Family

ID=90476159

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2023/119407 WO2024067206A1 (zh) 2022-09-30 2023-09-18 一种通信方法、通信装置及系统

Country Status (2)

Country Link
CN (1) CN117858197A (zh)
WO (1) WO2024067206A1 (zh)

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2018010127A1 (zh) * 2016-07-13 2018-01-18 广东欧珀移动通信有限公司 无线通信的方法、装置、接入网实体和终端设备
US20190191338A1 (en) * 2016-08-12 2019-06-20 Huawei Technologies Co.,Ltd. Data processing method and related device
WO2021134561A1 (zh) * 2019-12-31 2021-07-08 华为技术有限公司 通信方法和通信装置
CN113498125A (zh) * 2020-03-20 2021-10-12 华为技术有限公司 一种通信方法、接入网设备、终端设备和核心网设备
CN114145073A (zh) * 2019-09-29 2022-03-04 华为技术有限公司 通信方法和通信装置

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2018010127A1 (zh) * 2016-07-13 2018-01-18 广东欧珀移动通信有限公司 无线通信的方法、装置、接入网实体和终端设备
US20190191338A1 (en) * 2016-08-12 2019-06-20 Huawei Technologies Co.,Ltd. Data processing method and related device
CN114145073A (zh) * 2019-09-29 2022-03-04 华为技术有限公司 通信方法和通信装置
WO2021134561A1 (zh) * 2019-12-31 2021-07-08 华为技术有限公司 通信方法和通信装置
CN113498125A (zh) * 2020-03-20 2021-10-12 华为技术有限公司 一种通信方法、接入网设备、终端设备和核心网设备

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
OPPO: "Determining UE location and subsequent actions after initial registration – NTN access", 3GPP DRAFT; C1-214250, 3RD GENERATION PARTNERSHIP PROJECT (3GPP), MOBILE COMPETENCE CENTRE ; 650, ROUTE DES LUCIOLES ; F-06921 SOPHIA-ANTIPOLIS CEDEX ; FRANCE, vol. CT WG1, no. E-meeting; 20210819 - 20210827, 12 August 2021 (2021-08-12), Mobile Competence Centre ; 650, route des Lucioles ; F-06921 Sophia-Antipolis Cedex ; France , XP052040236 *

Also Published As

Publication number Publication date
CN117858197A (zh) 2024-04-09

Similar Documents

Publication Publication Date Title
JP7306444B2 (ja) 無線端末及びその方法
JP6969636B2 (ja) 無線端末、無線端末における方法、及び無線局
WO2020069681A1 (en) Handling of collision between pdu session establishment and release procedures
KR102337091B1 (ko) 다중 접속 통신 방법, 장치 및 단말
US11405830B2 (en) Information transmission method and apparatus
CN111279787A (zh) 用于处理无线电资源控制小区组配置的方法
WO2017211166A1 (zh) 可穿戴设备的无线承载配置方法与装置
WO2022011618A1 (zh) 信息处理方法、终端设备和网络设备
CN114125969B (zh) 一种连接重建方法、终端设备及存储介质
WO2022206313A1 (zh) 无线通信方法、装置及系统
WO2019105064A1 (en) Method and apparatus for signal transmission, network equipment
CN114600472B (zh) 通信方法及装置
CN117480815A (zh) 用于非地面网络卫星切换的方法、终端设备及网络设备
WO2024067206A1 (zh) 一种通信方法、通信装置及系统
WO2022206653A1 (zh) 一种通信方法及通信装置
WO2022160303A1 (zh) 服务质量参数处理方法、终端设备、网络功能实体和网络设备
RU2736782C1 (ru) Способ и устройство для передачи информации и сетевое устройство
WO2023123432A1 (zh) 无线通信的方法、终端和网络设备
WO2024146459A1 (zh) 通信方法与装置、终端设备、主节点和辅节点
WO2023216242A1 (zh) 连接配置方法和终端
WO2022262506A1 (zh) 中继通信的方法、装置和系统
WO2023168583A1 (zh) 通信方法、终端设备和网络设备
WO2024045923A1 (zh) 一种随机接入报告记录方法以及通信装置
WO2024016166A1 (zh) 无线通信方法及通信设备
WO2023015466A1 (en) Network triggered aggregation operations

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 23870440

Country of ref document: EP

Kind code of ref document: A1