WO2023202523A1 - 数据传输的方法和通信装置 - Google Patents

数据传输的方法和通信装置 Download PDF

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Publication number
WO2023202523A1
WO2023202523A1 PCT/CN2023/088652 CN2023088652W WO2023202523A1 WO 2023202523 A1 WO2023202523 A1 WO 2023202523A1 CN 2023088652 W CN2023088652 W CN 2023088652W WO 2023202523 A1 WO2023202523 A1 WO 2023202523A1
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WIPO (PCT)
Prior art keywords
network device
data
downlink data
terminal device
message
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PCT/CN2023/088652
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English (en)
French (fr)
Inventor
酉春华
娄崇
Original Assignee
华为技术有限公司
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Publication of WO2023202523A1 publication Critical patent/WO2023202523A1/zh

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L47/00—Traffic control in data switching networks
    • H04L47/10—Flow control; Congestion control
    • H04L47/27—Evaluation or update of window size, e.g. using information derived from acknowledged [ACK] packets
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W28/00—Network traffic management; Network resource management
    • H04W28/02—Traffic management, e.g. flow control or congestion control
    • H04W28/10—Flow control between communication endpoints

Definitions

  • the embodiments of the present application relate to the field of wireless communications, and more specifically, to a data transmission method and a communication device.
  • the terminal equipment communicates with the network side through a new base station node (generation nodeb, gNB).
  • the gNB also configures a RAN notification area (RAN based notification area, RNA) for the UE to move down.
  • RAN based notification area, RNA RAN based notification area
  • RNA RAN based notification area
  • the UE may leave the coverage area of the previous gNB.
  • the UE needs to transmit a small amount of data with the network side, it can establish a connection with other gNBs in the RNA through random access, thereby communicating with the network. side for small packet transmission.
  • the problem of packet loss is likely to occur. Therefore, how to reduce the packet loss rate is called an urgent problem to be solved.
  • This application provides a data transmission method and communication device, which can reduce the packet loss rate during the transmission of small data packets.
  • the first aspect provides a data transmission method, which can be executed by a first network device, or can also be executed by a component (such as a chip or circuit) of the first network device, which is not limited in this application.
  • a component such as a chip or circuit
  • the following description takes execution by the first network device as an example.
  • the method may include: a first network device receiving first downlink data from a second network device, where the first downlink data is small data; the first network device sending the first downlink data to a terminal device; A network device receives a first feedback message from the terminal device, the first feedback message is used to indicate successful or unsuccessful reception of the first downlink data, and the first feedback message corresponds to the first protocol layer; the first network device Send a second feedback message to the second network device according to the first feedback message.
  • the first feedback message is used to indicate that the first downlink data is successfully received.
  • the second feedback message is used to indicate that the terminal device successfully receives the first downlink data.
  • the first downlink data is received, and the second feedback message corresponds to the second protocol layer.
  • the first network device sends a second feedback message to the second network device.
  • the second feedback message indicates whether the terminal device has successfully or unsuccessfully received the first downlink data, so that the second network device
  • the device obtains whether the terminal device successfully receives the first downlink data, so that the sending window of the downlink data can be adjusted according to the data successfully received by the terminal device, thereby reducing the risk caused by the second network device being unable to know whether the first downlink data is successfully received by the terminal device. Adjust the packet loss caused by adjusting the sending window to reduce the packet loss rate.
  • the first feedback message includes at least one of the following: The sequence number of the first downlink data in the first protocol layer, the identifier of the radio bearer carrying the first downlink data, and the identifier of the logical channel carrying the first downlink data.
  • the second feedback message includes at least the following: One item: the sequence number of the first downlink data in the second protocol layer, the sequence number of the first downlink data in the first protocol layer, the identification of the radio bearer carrying the first downlink data, the The identifier of the logical channel of the first downlink data.
  • the method further includes: the first network device starting a timer according to the first feedback message.
  • the first network device sends a second feedback message to the second network device according to the first feedback message, including: when the timer times out, the The first network device sends a second feedback message to the second network device according to the first feedback message.
  • the terminal device may feedback to the first network device whether multiple downlink data are successfully received.
  • the first network device sets a timer and feedbacks to the second network device whether the terminal device successfully receives downlink data when the timer expires. Indicating the content in the feedback message can save signaling overhead.
  • the first network device sends a second feedback message to the second network device according to the first feedback message, including: the first network device sends a second feedback message to the second network device according to the first feedback message.
  • the feedback message confirms that the terminal device successfully receives M pieces of data of the first protocol layer, M is a positive integer; when among the M pieces of data, the number of data with consecutive sequence numbers of the second protocol layer is greater than or equal to N, the A network device sends a second feedback message to the second network device.
  • the second feedback message is used to indicate that the terminal device successfully receives N pieces of data of the second protocol layer, and the N pieces of data include the first downlink data, The N is a positive integer.
  • the above solution can save signaling overhead compared to indicating the content in the feedback message to the second network device every time it receives a feedback message from the terminal device.
  • the sequence numbers of the N pieces of data fed back by the first network device to the second network device are consecutive, which facilitates the second network device to directly push the sending window forward by N sequence numbers based on the second feedback message, and also saves the time spent on the second network device.
  • the first protocol layer is a radio link control layer
  • the second protocol layer is a packet data convergence layer
  • the method further includes: the first network device sending a first request message to the second network device, the first request message being used to request to obtain the terminal device
  • the first request message includes instruction information for indicating small data packet transmission
  • the first network device receives a first response message from the second network device, the first response message includes instruction information for indicating not to execute the anchor. Click relocation instructions.
  • the first network device requests the context of the terminal device from the second network device, indicating that the terminal device is no longer within the coverage of the second network device, and the second network device does not perform anchor point redirection, indicating that the second network device is still is the anchor point gNB.
  • the above solution in a scenario where anchor point relocation is not performed, allows the anchor point gNB to learn the status of the first protocol layer of the terminal device through the interaction between network devices based on the second protocol layer, so that the anchor point gNB can learn the status of the first protocol layer of the terminal device according to the terminal device's status.
  • the status of the first protocol layer adjusts the sending window to reduce the packet loss rate.
  • the method further includes: the first network device sending first indication information to the terminal device, the first indication information being used to indicate that the first network device supports Avoid data loss during the transmission of small data packets; the first network device receives fourth downlink data from the second network device, the fourth downlink data is data that the terminal device has not successfully received, and the fourth downlink data is small data packets. data; the first network device sends the fourth downlink data to the terminal device.
  • the first network device supports a mechanism to avoid data loss during the transmission of small data packets. It receives data that the terminal device has not successfully received from the second network device and retransmits the data to the terminal device, which can reduce the packet loss rate.
  • the method further includes: the first network device sending a second request message to the second network device, the second request message being used to request to obtain the terminal device context, the second request message includes instruction information for indicating small data packet transmission; the first network device receives a second response message from the second network device, the second response message includes instruction information for indicating execution anchor point Relocation instructions.
  • the first network device requests the context of the terminal device from the second network device, indicating that the terminal device is no longer within the coverage of the second network device, and the second network device performs anchor point relocation, indicating that the anchor point gNB is the first network equipment.
  • the above solution uses the anchor point gNB to forward the fourth downlink data to the terminal device through the anchor point gNB before relocating the anchor point, which can reduce the packet loss caused by the terminal device not being within the coverage of the second network device and reduce the packet loss rate. .
  • the method further includes: the first network device sending a third request message to the second network device, the third request message being used to request to obtain the terminal device
  • the third request message includes indication information for indicating small data packet transmission
  • the first network device receives a third response message from the second network device, the third response message includes indication information for indicating not to execute the anchor Click relocation instructions.
  • the first network device requests the context of the terminal device from the second network device, indicating that the terminal device is no longer within the coverage of the second network device, and the second network device does not perform anchor point relocation, indicating that the anchor point gNB is still the third network device. 2. Network equipment. In the above solution, the anchor gNB continues to forward the fourth downlink data to the terminal device through the first network device, which can reduce packet loss caused by the terminal device not being within the coverage of the second network device and reduce the packet loss rate.
  • the method further includes: the first network device sends a radio resource control release message to the terminal device, the radio resource control release message includes Y, where Y is small data The number of cell reselections during packet transmission, Y is a positive integer.
  • the second aspect provides a data transmission method, which can be executed by a second network device, or can also be executed by a component (such as a chip or circuit) of the second network device, which is not limited in this application.
  • a component such as a chip or circuit
  • the following description takes execution by the second network device as an example.
  • the method may include: the second network device sends first downlink data to the first network device, the first downlink data is small data, and the first network device is configured to send the first downlink data to the terminal device;
  • the second network device receives a second feedback message from the first network device.
  • the second feedback message is used to indicate whether the terminal device has successfully received or failed to receive the first downlink data.
  • the second feedback message is consistent with the second protocol. layer correspondence;
  • the second network device determines a second sending window based on the first sending window and the second feedback message.
  • the first sending window contains the sequence number of the first downlink data.
  • the second sending window includes the sequence number of the downlink data that has not been sent to the terminal device.
  • the second network device sends the first downlink data to the terminal device through the first network device, determines whether the terminal device successfully receives the first downlink data according to the second feedback message sent by the first network device, and determines whether the terminal device successfully receives the first downlink data according to the second feedback message. Message adjustment sending window. If the second feedback message indicates that the terminal device successfully receives the first downlink data, the second network device pushes the sending window forward.
  • the second feedback message includes at least one of the following: the sequence number of the first downlink data in the second protocol layer, the sequence number of the first downlink data in the second protocol layer, The superframe number of the second protocol layer, the identifier of the radio bearer carrying the first downlink data, and the identifier of the logical channel carrying the first downlink data.
  • the method further includes: the second network device determining, based on the second feedback message, that data corresponding to the first L sequence numbers of the first sending window have been sent by the second network device. If the terminal device receives successfully, the starting sequence number of the second sending window is equal to the sequence number corresponding to the L+1th data of the first sending window, and L is a positive integer.
  • sequence numbers of the N pieces of data fed back by the first network device to the second network device are consecutive, which can facilitate the second network device to directly push the sending window forward by N sequence numbers based on the second feedback message, and can also save time.
  • the second protocol layer is a packet data convergence layer.
  • the method further includes: the second network device receiving a first request message from the first network device, the first request message being used to request acquisition of the terminal
  • the first request message includes indication information for indicating small data packet transmission
  • the second network device sends a first response message to the first network device, the first response message includes indication information for indicating not to execute the anchor. Click relocation instructions.
  • the first network device requests the context of the terminal device from the second network device, indicating that the terminal device is no longer within the coverage of the second network device, and the second network device does not perform anchor point redirection, indicating that the second network device is still is the anchor point gNB.
  • the above solution in a scenario where anchor point relocation is not performed, allows the anchor point gNB to learn the status of the first protocol layer of the terminal device through the interaction between network devices based on the second protocol layer, so that the anchor point gNB can learn the status of the first protocol layer of the terminal device according to the terminal device's status.
  • the status of the first protocol layer adjusts the sending window to reduce the packet loss rate.
  • some implementations of the second aspect include: the second network device sending second instruction information to the terminal device, the second instruction information being used to instruct to avoid data loss during small data packet transmission. ;
  • the second network device sends fourth downlink data, and the fourth downlink data is small data;
  • the second network device receives a first status report, and the first status report includes instructions for indicating that the terminal device has not successfully received the fourth Instruction information of downlink data;
  • the second network device sends the fourth downlink data to the first network device.
  • the second network device supports a mechanism to avoid data loss during the transmission of small data packets, sends the data that the terminal device has not successfully received to the second network device, and retransmits the data to the terminal device through the second network device. Reduce packet loss rate.
  • the second network device sends fourth downlink data, including: the second network device sends the fourth downlink data to the terminal device; the second network device Receiving the first status report includes: the second network device receives the first status report from the terminal device.
  • the method further includes: the second network device receiving a second request message from the first network device, the second request message being used to request to obtain the terminal
  • the second request message includes instruction information for indicating small data packet transmission
  • the second network device sends a second response message to the second network device, the second response message includes instruction information for indicating execution anchor point Relocation instructions.
  • the first network device requests the context of the terminal device from the second network device, indicating that the terminal device is no longer within the coverage of the second network device, and the second network device performs anchor point relocation, indicating that the anchor point gNB is the first network equipment.
  • the above solution uses the anchor point gNB to forward the fourth downlink data to the terminal device through the anchor point gNB before relocating the anchor point, which can reduce packet loss caused by the terminal device not being within the coverage of the second network device and reduce the loss of packets. Package rate.
  • the second network device sends fourth downlink data, including: the second network device sends the fourth downlink data to a third network device; the second network device
  • the device receiving the first status report includes: the second network device receiving the first status report from the third network device.
  • the method further includes: the second network device sending a fourth request message to the third network device, the fourth request message being used to request the fourth downlink data status report.
  • the method further includes: the second network device receiving a third request message from the first network device, the third request message being used to request to obtain the terminal
  • the third request message includes instruction information for indicating small data packet transmission
  • the second network device sends a third response message to the first network device, the third response message includes instruction information for indicating not to execute the anchor. Click relocation instructions.
  • the first network device requests the context of the terminal device from the second network device, indicating that the terminal device is no longer within the coverage of the second network device, and the second network device does not perform anchor point relocation, indicating that the anchor point gNB is still the third network device. 2. Network equipment. In the above solution, the anchor gNB continues to forward the fourth downlink data to the terminal device through the first network device, which can reduce packet loss caused by the terminal device not being within the coverage of the second network device and reduce the packet loss rate.
  • the method further includes: the first network device sends a radio resource control release message to the terminal device, the radio resource control release message includes Y, where Y is small data The number of cell reselections during packet transmission, Y is a positive integer.
  • a data transmission method is provided, which method can be executed by a terminal device, or can also be executed by a component (such as a chip or circuit) of the terminal device, which is not limited in this application.
  • a component such as a chip or circuit
  • the following description takes execution by a terminal device as an example.
  • the method may include: the terminal device receives second indication information from the second network device, the second indication information is used to indicate to avoid data loss during the transmission of small data packets; the terminal device receives fourth downlink data, the fourth downlink data The data is small data; the terminal device sends indication information indicating that the fourth downlink data has not been successfully received; the terminal device receives first indication information from the first network device, the first indication information is used to indicate the first The network device supports avoiding data loss during small data packet transmission; the terminal device receives fourth downlink data from the first network device.
  • the terminal device determines that the second network device supports a mechanism to avoid data loss during the transmission of small data packets based on the second instruction information, and determines based on the first instruction information that the first network device supports a mechanism to avoid data loss during the transmission of small data packets. , the terminal device has received unsuccessfully received fourth downlink data from the second network device from the first network device, which can reduce the packet loss rate during the transmission of small data packets.
  • the terminal device receiving fourth downlink data includes: the terminal device receiving the fourth downlink data from the second network device; and the terminal device sending for The indication information indicating that the fourth downlink data is not successfully received includes: the terminal device sends a first status report to the second network device, and the first status report includes the indication information.
  • the terminal device receiving fourth downlink data includes: the terminal device receiving the fourth downlink data from the third network device; and the terminal device sending for The indication information indicating that the fourth downlink data has not been successfully received includes: the terminal device sends a second status report to the third network device, and the second status report includes the indication information.
  • the method further includes: the terminal device receives from The radio resource control release message of the network device, the radio resource control release message includes Y, Y is the number of cell reselections during the small data packet transmission process, and Y is a positive integer; the terminal device initiates the small data packet transmission process; the terminal The device records the number of cell reselections; when the number of cell reselections recorded by the terminal device is ⁇ Y, the terminal device switches to the radio resource control idle state, or the terminal device sends non-small data packet transmission to the network device recovery request message.
  • the fourth aspect provides a data transmission method, which can be executed by a third network device, or can also be executed by a component (such as a chip or circuit) of the third network device, which is not limited in this application.
  • a component such as a chip or circuit
  • the following description takes the execution by the third network device as an example.
  • the method may include: the third network device receives fourth downlink data from the second network device, and the fourth downlink data is small data; the third network device sends the fourth downlink data to the terminal device; the third network device Receive a second status report from the terminal device, the second status report including indication information indicating that the terminal device has not successfully received the fourth downlink data; the third network device reports to the second status report according to the second status report.
  • the network device sends a first status report, where the first status report includes indication information indicating that the terminal device has not successfully received the fourth downlink data.
  • the method further includes: the third network device receiving a fourth request message from the second network device, the fourth request message being used to request the fourth Status reporting of downstream data.
  • the method further includes: the third network device releases the link with the terminal device and stops communicating with the terminal device.
  • a data transmission method is provided.
  • the method can be executed by the first network device, or can also be executed by a component (such as a chip or circuit) of the first network device.
  • a component such as a chip or circuit
  • This application is not limited to this.
  • the following description takes execution by the first network device as an example.
  • the method may include: the first network device sending first indication information to the terminal device, the first indication information being used to instruct the first network device to support avoiding data loss during small data packet transmission; the first network device receiving from The fourth downlink data of the second network device, the fourth downlink data is unsuccessfully received by the terminal device, and the fourth downlink data is small data; the first network device sends the fourth downlink data to the terminal device.
  • the method further includes: the first network device sending a second request message to the second network device, the second request message being used to request acquisition of the terminal device context, the second request message includes instruction information for indicating small data packet transmission; the first network device receives a second response message from the second network device, the second response message includes instruction information for indicating execution anchor point Relocation instructions.
  • the method further includes: the first network device sending a third request message to the second network device, the third request message being used to request acquisition of the terminal device
  • the third request message includes indication information for indicating small data packet transmission
  • the first network device receives a third response message from the second network device, the third response message includes indication information for indicating not to execute the anchor Click relocation instructions.
  • the method further includes: the first network device sending a radio resource control release message to the terminal device, the radio resource control release message including Y, where Y is small data The number of cell reselections during packet transmission, Y is a positive integer.
  • a sixth aspect provides a data transmission method, which may be executed by a second network device, or may be executed by a component (such as a chip or circuit) of the second network device, which is not limited in this application.
  • a component such as a chip or circuit
  • the following description takes execution by the second network device as an example.
  • the method may include: the second network device sends second indication information to the terminal device, the second indication information is used to indicate to avoid data loss during the transmission of small data packets; the second network device sends fourth downlink data, the fourth The downlink data is small data; the second network device receives a first status report, the first status report includes indication information indicating that the terminal device has not successfully received the fourth downlink data; the second network device reports to the first network The device sends the fourth downlink data.
  • the second network device sends fourth downlink data, including: the second network device sends the fourth downlink data to the terminal device; the second network device Receiving the first status report includes: the second network device receives the first status report from the terminal device.
  • the method further includes: the second network device receiving a second request message from the first network device, the second request message being used to request acquisition of the terminal
  • the second request message includes instruction information for indicating small data packet transmission
  • the second network device sends a second response message to the second network device, the second response message includes instruction information for indicating execution anchor point Relocation instructions.
  • the second network device sends fourth downlink data, including: the second network device sends the fourth downlink data to a third network device; the second network device The device receiving the first status report includes: the second network device receiving the first status report from the third network device.
  • the method further includes: the second network device sending a fourth request message to the third network device, the fourth request message being used to request the fourth downlink data status report.
  • the method further includes: the second network device receiving a third request message from the first network device, the third request message being used to request acquisition of the terminal
  • the third request message includes instruction information for indicating small data packet transmission
  • the second network device sends a third response message to the first network device, the third response message includes instruction information for indicating not to execute the anchor. Click relocation instructions.
  • a seventh aspect provides a data transmission method, which can be executed by the first network device, or can also be executed by a component (such as a chip or circuit) of the first network device, which is not limited in this application.
  • a component such as a chip or circuit
  • the following description takes execution by the first network device as an example.
  • the method may include: the first network device sending first indication information to the terminal device, the first indication information being used to instruct the first network device to support avoiding data loss during small data packet transmission; the first network device receiving from The fourth downlink data of the second network device, the fourth downlink data is unsuccessfully received by the terminal device, and the fourth downlink data is small data; the first network device sends the fourth downlink data to the terminal device.
  • the method further includes: the first network device sending a second request message to the second network device, the second request message being used to request acquisition of the terminal device context, the second request message includes instruction information for indicating small data packet transmission; the first network device receives a second response message from the second network device, the second response message includes instruction information for indicating execution anchor point Relocation instructions.
  • the method further includes: the first network device sending a third request message to the second network device, the third request message being used to request acquisition of the terminal device
  • the third request message includes indication information for indicating small data packet transmission
  • the first network device receives a third response message from the second network device, the third response message includes indication information for indicating not to execute the anchor Click relocation instructions.
  • the method further includes: the first network device sends a radio resource control release message to the terminal device, the radio resource control release message includes Y, where Y is small data Bao Chuan The number of cell reselections during the losing process, Y is a positive integer.
  • An eighth aspect provides a data transmission method, which may be executed by a second network device, or may be executed by a component (such as a chip or circuit) of the second network device, which is not limited in this application.
  • a component such as a chip or circuit
  • the following description takes execution by the second network device as an example.
  • the method may include: the second network device sends second indication information to the terminal device, the second indication information is used to indicate to avoid data loss during the transmission of small data packets; the second network device sends fourth downlink data, the fourth The downlink data is small data; the second network device receives a first status report, the first status report includes indication information indicating that the terminal device has not successfully received the fourth downlink data; the second network device reports to the first network The device sends the fourth downlink data.
  • the second network device sends fourth downlink data, including: the second network device sends the fourth downlink data to the terminal device; the second network device Receiving the first status report includes: the second network device receives the first status report from the terminal device.
  • the method further includes: the second network device receiving a second request message from the first network device, the second request message being used to request to obtain the terminal
  • the second request message includes instruction information for indicating small data packet transmission
  • the second network device sends a second response message to the second network device, the second response message includes instruction information for indicating execution anchor point Relocation instructions.
  • the second network device sends fourth downlink data, including: the second network device sends the fourth downlink data to a third network device; the second network device The device receiving the first status report includes: the second network device receiving the first status report from the third network device.
  • the method further includes: the second network device sending a fourth request message to the third network device, the fourth request message being used to request the fourth downlink data status report.
  • the method further includes: the second network device receiving a third request message from the first network device, the third request message being used to request acquisition of the terminal
  • the third request message includes instruction information for indicating small data packet transmission
  • the second network device sends a third response message to the first network device, the third response message includes instruction information for indicating not to execute the anchor. Click relocation instructions.
  • the method further includes: the first network device sends a radio resource control release message to the terminal device, the radio resource control release message includes Y, where Y is small data The number of cell reselections during packet transmission, Y is a positive integer.
  • the network device sends a radio resource control release message to the terminal device.
  • the radio resource control release message includes Y, where Y is the number of cell reselections during small data packet transmission, and Y is a positive integer.
  • a data transmission method is provided.
  • the method can be executed by the first network device, or can also be executed by a component (such as a chip or circuit) of the first network device.
  • a component such as a chip or circuit
  • This application is not limited to this.
  • the following description takes execution by the first network device as an example.
  • the method may include: the first network device sending first indication information to the terminal device, the first indication information being used to instruct the first network device to support avoiding data loss during small data packet transmission; the first network device receiving from The first uplink data of the second network device, the first uplink data is the data successfully received by the second network device, the first uplink data is small data; the first network device receives the second uplink data from the terminal device , the second uplink data is data from the terminal device that was unsuccessfully received by the second network device, and the second uplink data is small data.
  • the method further includes: the first network device transmits a message to the The second network device sends a second request message, the second request message is used to request to obtain the context of the terminal device, the second request message includes instruction information used to indicate small data packet transmission; the first network device receives from the A second response message from the second network device, the second response message is used to indicate that the second network device decides to perform anchor point relocation.
  • a data transmission method is provided.
  • the method may be executed by a second network device, or may be executed by a component (such as a chip or circuit) of the second network device.
  • This application is not limited to this.
  • the following description takes execution by the second network device as an example.
  • the method may include: the second network device sends second instruction information to the terminal device, the second instruction information is used to instruct to avoid data loss during the transmission of small data packets; the second network device receives a fourth uplink signal from the terminal device. data, the fourth uplink data is small data; the second network device sends a third status report to the terminal device, the third status report includes at least one of the following indication information: used to indicate successful reception of the first uplink data Instruction information used to indicate that the second uplink data has not been successfully received.
  • the fourth uplink data includes the first uplink data and the second uplink data; the second network device sends the first uplink data to the first network device. Upstream data.
  • the method further includes: the second network device receiving a second request message from the second network device, the second request message being used to request to obtain the terminal
  • the second request message includes instruction information for instructing small data packet transmission
  • the second network device sends a second response message to the second network device, the second response message is used to instruct the second network device Decided to perform anchor relocation.
  • An eleventh aspect provides a data transmission method, which can be executed by a terminal device, or can also be executed by a component (such as a chip or circuit) of the terminal device, which is not limited in this application.
  • a component such as a chip or circuit
  • the following description takes execution by a terminal device as an example.
  • the method may include: the terminal device receives second indication information from the second network device, the second indication information is used to indicate to avoid data loss during the transmission of small data packets; the terminal device sends a fourth uplink to the second network device.
  • data the fourth uplink data is small data
  • the terminal device receives a third status report from the second network device, the third status report includes at least one of the following indication information: used to indicate successful reception of the first uplink Data indication information, indication information indicating unsuccessful reception of the second uplink data, wherein the fourth uplink data includes the first uplink data and the second uplink data; the terminal device receives the third uplink data from the first network device.
  • An indication information the first indication information is used to instruct the first network device to support avoiding data loss during small data packet transmission; the terminal device sends the second uplink data to the first network device.
  • a twelfth aspect provides a data transmission method, which can be executed by a terminal device, or can also be executed by a component (such as a chip or circuit) of the terminal device, which is not limited in this application.
  • a component such as a chip or circuit
  • the following description takes execution by a terminal device as an example.
  • the method may include: the terminal device receives a radio resource control release message from the network device, the radio resource control release message includes Y, Y is the number of cell reselections during the small data packet transmission process, and Y is a positive integer; the terminal device initiates Small data packet transmission process; the terminal equipment records the number of cell reselections; when the number of cell reselections recorded by the terminal equipment is ⁇ Y, the terminal equipment switches to the radio resource control idle state, or the terminal equipment switches to the wireless resource control idle state.
  • Network devices send resume request messages for non-small packet transfers.
  • the above scheme sets a threshold for the number of cell reselections of the terminal equipment, and the terminal equipment counts the number of cell reselections. When the number of cell reselections reaches the threshold, the cell reselection is stopped or switched to the idle state or initiates non-small data packets.
  • the transmission recovery process reduces the reduction in communication efficiency caused by continuous small data packet transmission failures and improves communication efficiency.
  • a thirteenth aspect provides a data transmission device, which is used to perform the method in any of the possible implementation modes of the first to twelfth aspects.
  • the device may include units and/or modules for performing the method in any possible implementation of the first to twelfth aspects, such as a processing unit and/or a communication unit.
  • the device is a communication device (such as a network device or a terminal device).
  • the communication unit may be a transceiver, or an input/output interface; the processing unit may be at least one processor.
  • the transceiver may be a transceiver circuit.
  • the input/output interface may be an input/output circuit.
  • the device is a chip, chip system or circuit used in communication equipment (such as network equipment, such as terminal equipment).
  • the communication unit may be an input/output interface, interface circuit, output circuit, input circuit, pin or related circuit on the chip, chip system or circuit, etc.
  • the processing unit may be at least one processor, processing circuit or logic circuit, etc.
  • a data transmission device includes: at least one processor for executing computer programs or instructions stored in a memory to execute any of the possible implementation methods of the first to twelfth aspects above. method in.
  • the device further includes a memory for storing computer programs or instructions.
  • the device further includes a communication interface, through which the processor reads the computer program or instructions stored in the memory.
  • the device is a communication device (such as a network device or a terminal device).
  • the device is a chip, chip system or circuit used in communication equipment (such as network equipment, such as terminal equipment).
  • the present application provides a processor for executing the methods provided in the above first to twelfth aspects.
  • processor output, reception, input and other operations can be understood as processor output, reception, input and other operations.
  • transmitting and receiving operations performed by the radio frequency circuit and the antenna, which is not limited in this application.
  • a computer-readable storage medium stores a program code for device execution.
  • the program code includes a possible implementation manner for executing any of the above-mentioned first to twelfth aspects. method in.
  • a computer program product containing instructions is provided.
  • the computer program product When the computer program product is run on a computer, it causes the computer to execute the method in any of the possible implementation modes of the first aspect to the twelfth aspect.
  • a communication system including the aforementioned first network device and second network device.
  • Figure 1 shows a schematic diagram of a communication system applying an embodiment of the present application.
  • Figure 2 shows a schematic diagram of data transmission between UE and gNB through the protocol stack.
  • Figure 3 (a) shows the protocol stack distribution in the scenario where the previous serving gNB decides not to perform anchor relocation.
  • Figure 3 (b) shows the previous serving gNB decides to perform anchor relocation. Protocol stack distribution in positioning scenarios.
  • Figure 4 shows a schematic diagram of the data transmission method 100 provided by this application.
  • FIG. 5 shows a schematic diagram of the data transmission method 110 provided by this application.
  • Figure 6 shows a schematic diagram of the data transmission method 120 provided by this application.
  • Figure 7 shows a schematic diagram of the data transmission method 200 provided by this application.
  • Figure 8 shows a schematic diagram of the data transmission method 300 provided by this application.
  • Figure 9 shows a schematic diagram of the data transmission method 400 provided by this application.
  • Figure 10 shows a schematic flow chart of the data transmission method 500 provided by this application.
  • Figure 11 shows a schematic block diagram of a data transmission method 500 provided by this application.
  • FIG. 12 is a schematic diagram of a data transmission device 600 provided by an embodiment of the present application.
  • FIG. 13 is a schematic diagram of another data transmission device 700 provided by an embodiment of the present application.
  • Figure 14 is a schematic diagram of a chip system 800 provided by an embodiment of the present application.
  • the communication method provided by this application can be applied to various communication systems, for example, it can be the Internet of Things (IoT), narrowband Internet of things (NB-IoT), long term evolution (long term evolution) , LTE), it can also be the fifth generation ( 5th generation, 5G) communication system, it can also be a hybrid architecture of LTE and 5G, it can also be a 5G new radio (NR) system, and 6G or emerging in future communication development. new communication systems, etc.
  • the communication system described in this application may also be a machine to machine (M2M) network or other networks.
  • M2M machine to machine
  • FIG. 1 shows a schematic diagram of a communication system applying an embodiment of the present application.
  • the 5G access point is composed of the next generation radio access network (NG-RAN) of the base station node.
  • the NG-RAN node may be a 5G new base station node (generation nodeb, gNB), or It may be an LTE evolution base station node (next generation enodeb, ng-eNB).
  • gNB uses NR's user plane and control plane protocol stack
  • ng-eNB uses evolved universal terrestrial radio access (E- UTRA) user plane and control plane protocol stack.
  • E- UTRA evolved universal terrestrial radio access
  • gNB and gNB, ng-eNB and ng-eNB, gNB and ng-eNB are interconnected through the Xn interface.
  • gNB and ng-eNB are connected to the 5G core network through the NG interface.
  • the control plane is connected to the access network and mobility management module (access and mobility management function, AMF) through the NG-C interface, and the user plane is connected through the NG-U interface.
  • AMF access and mobility management function
  • UPF user plane function
  • the RRC status includes: Radio Resource Control connected state (RRC connected), Radio Resource Control idle state (RRCidle) or Radio Resource Control inactive state (RRCinactive).
  • RRC Radio Resource Control
  • SRB1 signaling radio bearer 1
  • the terminal device moves under the RAN based notification area (RNA) without knowing the access network device.
  • the terminal device saves its own context, and the last serving gNB (last serving gNB) saves the context of the terminal device, as well as the NG connection with AMF and UPF.
  • the dedicated RRC connection between the terminal equipment and the access network equipment is suspended and can be restored later.
  • the terminal device can perform cell reselection in RRC inactive.
  • RRC inactive can quickly restore the user equipment (UE) to RRCconnected without reconnecting.
  • RRC inactive is similar to RRCidle. They can only receive content from the public search space (such as paging and broadcasting) and can perform cell reselection.
  • RRC inactive can obtain a power consumption level similar to that of RRC idle state because the UE in RRC inactive will suspend data processing. If the UE moves in the same RNA, it does not need to exchange information with the gNB. However, if the UE moves out of the RNA range, the RNA update process needs to be started.
  • the UE in RRC inactive can have a lower data transmission recovery delay because the UE in RRC inactive can quickly migrate to the RRC connected state through the RRC recovery (resume) process.
  • the CM state consists of the establishment and release of the non-access stratum (NAS) signaling connection between the UE and the AMF.
  • the NAS signaling connection is used for NAS signaling interaction between the UE and the core network. It includes two parts of connections: 1) The signaling connection between the UE and the access network (AN), such as the RRC connection in the 3rd generation partnership project (3GPP) access mode, non-3GPP Interworking function (non-3GPP interworking function, N3IWF), 2) N2 connection between AN and AMF.
  • AN access network
  • SDT Before the emergence of SDT, if the terminal device in the inactive state needs to transmit data packets, it must first trigger the RRC connection recovery process to switch to the connected state.
  • SDT technology enables terminal equipment to transmit short data packets in an inactive state, avoiding the signaling overhead and energy consumption caused by frequently triggering the RRC connection recovery process.
  • SDT SDT
  • smartphone-related businesses such as heartbeat packets or push messages of applications (APPs); and non-smartphone-related businesses, such as periodic data of wearable devices (such as heartbeats). packets), periodic data sent by industrial wireless sensor networks, etc.
  • APPs applications
  • non-smartphone-related businesses such as periodic data of wearable devices (such as heartbeats). packets), periodic data sent by industrial wireless sensor networks, etc.
  • the specific size of small data may not be limited in the embodiments of the present application. For example, data packets of 100 to 300 bytes may be considered small data.
  • data transmission and small data packet transmission described in the embodiments of this application below may refer to SDT, and the uplink data, downlink data and data packets described in the embodiments of this application may all be small data.
  • the protocol stack includes the following protocol layers: service data adaptation protocol (SDAP), packet data convergence protocol (PDCP), radio link control (RLC) ), media access control (MAC), physical (PHY), different protocol layers have their own functions.
  • SDAP service data adaptation protocol
  • PDCP packet data convergence protocol
  • RLC radio link control
  • MAC media access control
  • PHY physical
  • FIG. 2 shows a schematic diagram of data transmission between UE and gNB through the protocol stack.
  • gNB When the UE is the sender, gNB is the receiver; when the UE is the receiver, gNB is the sender.
  • the order of data processing on the sender side SDAP->PDCP->RLC->MAC->PHY.
  • SDAP's main processing includes: mapping the quality of service (QoS) flow to the radio bearer (RB), and submitting the processed data to PDCP.
  • the main processing of data in PDCP includes: encryption, integrity protection, header compression, adding PDCP serial number (SN), etc.
  • the data of different RBs is obtained at the PDCP layer, and the terminal performs its own processing on different RBs.
  • One logical channel corresponds to one RB, and the processed data is submitted to the RLC.
  • the main processing of data in RLC for acknowledgment mode (AM), automatic repeat-request (ARQ), segmentation, reassembly, adding RLCSN, for unacknowledged mode (UM), segmentation Segment, reassemble, add RLCSN.
  • the processing of data in the MAC mainly includes the multiplexing of logical channels and hybrid automatic repeat-request (HARQ).
  • a data packet follows the above sequence It is processed and finally sent out by the PHY. On the receiving side, work backwards in reverse order.
  • the following is an introduction based on the window push timer of the PDCP sending window. If the receiver's RLC determines that it has received a data packet, it will notify the receiver's PDCP through internal implementation so that PDCP can maintain the PDCP receiving window. If the RLC feedback of a data packet is an acknowledgment (ACK), then the PDCP receiving window can be pushed forward. Otherwise, the window remains unchanged, waiting for the sender to retransmit the data packet and starting the window pushing timer. . When the window push timer times out, regardless of whether the data packet is retransmitted or whether the retransmitted data packet is successfully received, the receiver's PDCP will push the PDCP receive window to prevent the PDCP receive window from getting stuck in a certain position.
  • ACK acknowledgment
  • the receiver indicates the RLC status to the sender, and the sender maintains the PDCP sending window according to the instructions of the receiver.
  • the maintenance method is similar to that of the receiver.
  • the current sending window of PDCP is [0,99], that is to say, PDCP is waiting to send PDCP SN packets from 0 to 99.
  • the PDCP sending window can be pushed forward to [2,101].
  • the window push timer times out the sending window can also be pushed to [2,101].
  • the sender will no longer resend data packets with PDCP SNs of 0 and 1.
  • the UE communicates with the network through a gNB.
  • the gNB configures an identity for the UE, such as a wireless network temporary identity.
  • the gNB also configures an RNA for the UE.
  • the gNB that configures RNA for the UE is called the previous serving gNB, and other gNBs within the range of the RNA are called receiving gNBs (receiving gNB).
  • the receiving gNB receives the identifier from the UE, it can determine according to the identifier to request the context of the UE from the previous serving gNB.
  • the terminal equipment when the terminal equipment (user equipment, UE) is not within the coverage of the previous serving gNB after moving, it can access the network through the receiving gNB.
  • the UE sends an RRC resume request message (RRC resume request) to the receiving gNB.
  • the RRC recovery request message carries the identifier, which is allocated by the previous serving gNB.
  • the receiving gNB After receiving the RRC recovery request message, the receiving gNB sends a retrieve UE context request message (retrieve UE context request) to the previous serving gNB (last serving gNB) based on the identifier.
  • the previous serving gNB decides whether to perform anchor point relocation after receiving the Get UE Context Request message. For example, the previous serving gNB may decide whether to perform anchor point relocation based on its own load, or may decide whether to perform anchor point relocation based on the information provided by the received gNB.
  • the terminal device may also perform cell reselection to the cell where the receiving gNB is located.
  • the protocol stack distribution is as shown in (a) in Figure 3.
  • the arrow represents the transmission path of the first data, and the first data may be user data or a non-access stratum (non-access stratum, NAS) message.
  • the UE sends the first data to the receiving gNB, and then the receiving gNB sends the first data to the previous serving gNB through the Xn interface.
  • the previous serving gNB is the anchor gNB.
  • the UE sends the first data in the order of SDAP->PDCP->RLC->MAC->PHY.
  • the receiving gNB After receiving the first data in the order of PHY->MAC->RLC, the receiving gNB sends the first data to the RLC service data unit through the Xn interface based on the RLC service data unit.
  • the previous serving gNB sends the first data.
  • the protocol stack distribution is shown in (b) in Figure 3.
  • arrows indicate the transmission path of user data or non-access stratum (NAS) messages.
  • the UE sends the first data in the order of SDAP->PDCP->RLC->MAC->PHY, and the receiving gNB receives the first data in the order of PHY->MAC->RLC->PDCP->SDAP.
  • the anchor point gNB is the receiving gNB.
  • the anchor point gNB is the previous serving gNB.
  • the UE can communicate with the anchor point by accepting the gNB.
  • the UE can directly communicate with the anchor point gNB.
  • Figure 4 shows a schematic diagram of the data transmission method 100 provided by this application.
  • the second network device sends first downlink data to the first network device.
  • the first network device receives the first downlink data from the second network device, and the first downlink data is small data.
  • the first network device and the second network device may be two gNBs in the same RNA, and the second network device saves the context of the terminal device.
  • the first network device may be the receiving gNB
  • the second network device may be the previous serving gNB.
  • the protocol stack distribution of the terminal device, the first network device, and the second network device can be seen in (a) in Figure 3 .
  • the second network device sends the first downlink data to the second network device based on the packet data convergence layer.
  • the first network device sends a first request message to the second network device.
  • the first request message is used to request to obtain the context of the terminal device, and the first request message includes instruction information used to instruct small data packet transmission.
  • the first network device receives a first response message from the second network device, where the first response message includes indication information indicating not to perform anchor point relocation.
  • the second network device is still the anchor gNB, the RLC, MAC, and PHY in the protocol stack are migrated to the first network device, and PDCP and SDAP are still on the second network device, such as (a) in Figure 3 Show.
  • the second response message includes the SDT context.
  • SDT context please refer to S204 of the method 200.
  • the first network device sends first downlink data to the terminal device, and accordingly, the terminal device receives the first downlink data from the first network device.
  • the first network device sends the first downlink data to the terminal device based on the radio link control layer.
  • the terminal device sends a first feedback message to the first network device.
  • the first network device receives the first feedback message from the terminal device.
  • the first feedback message is used to indicate successful or unsuccessful reception of the first downlink data.
  • the feedback message corresponds to the first protocol layer.
  • the first protocol layer is a radio link control layer.
  • the first feedback message includes at least one of the following: the sequence number of the first downlink data in the radio link control layer, the identification of the radio bearer carrying the first downlink data, and the logical channel carrying the first downlink data. logo.
  • the first network device sends a second feedback message to the second network device according to the first feedback message.
  • the second network device receives the second feedback message from the first network device, and the second feedback message corresponds to the second feedback message. protocol layer.
  • the first feedback message is used to indicate that the first downlink data is successfully received
  • the second feedback message is used to indicate that the terminal device successfully receives the first downlink data.
  • the first feedback message is used to indicate that the first downlink data has not been successfully received
  • the second feedback message is used to indicate that the terminal device has not successfully received the first downlink data.
  • the second protocol layer is a packet data convergence layer.
  • the second feedback message includes at least one of the following: the sequence number of the first downlink data at the packet data convergence layer, the sequence number of the first downlink data at the radio link control layer, the sequence number carrying the first downlink data.
  • Implementation method 1 The first network device sets a timer, and executes S104 when the timer times out.
  • the start time of the timer may be the time when the first network device receives a feedback message corresponding to downlink data.
  • the feedback message here is used to indicate successful or unsuccessful reception of the one downlink data.
  • the one downlink data may be the first downlink data, or may be downlink data other than the first downlink data.
  • the timing duration of the timer may be preconfigured or determined by the first network device or the second network device.
  • Implementation manner 2 The first network device determines according to the first feedback message that the data of the wireless link control layer successfully received by the terminal device includes at least N pieces of data with consecutive sequence numbers, and the N pieces of data include the first downlink data, and performs S104. In other words, every time the first network device determines that the sequence numbers of N pieces of data are consecutive, it can indicate to the second network device that N pieces of data have been successfully received, and the N pieces of data include the first downlink data.
  • the first network device determines according to the first feedback message that the terminal device successfully receives M pieces of data of the first protocol layer, where M is a positive integer, and the M pieces of data include first downlink data.
  • M data do not include data that the first network device has indicated to the second network device and that the terminal device has successfully received. In other words, the first network device has not indicated successful reception to the second network device.
  • M data may also receive feedback message A. Feedback message A is used to indicate successful reception of downlink data A, where downlink data A is downlink data other than the first downlink data.
  • the M pieces of data include the first downlink data and downlink data A.
  • Step 2 When the number of data with consecutive sequence numbers among the M pieces of data is greater than or equal to N, the first network device sends a second feedback message to the second network device.
  • the second feedback message Used to indicate that the terminal device successfully receives N pieces of data of the second protocol layer, where the N pieces of data include the first downlink data, and the N is a positive integer.
  • the M pieces of data are sorted according to the sequence number of the second protocol layer corresponding to each data.
  • the first network device can send the sequence number to the second network device. Second feedback message.
  • the N pieces of data indicated in the second feedback message are the first N pieces of data arranged in ascending order from the sequence numbers of the packet data aggregation layer of the M pieces of data.
  • the second network device determines the second sending window based on the first sending window and the second feedback message.
  • the first sending window contains the sequence number of the first downlink data.
  • the second sending window contains the sequence number of the downlink data that has not been sent to the terminal device.
  • the second network device may not adjust the first sending window. In other words, the first sending window and the second sending window are consistent.
  • the second network device determines according to the second feedback message that the data corresponding to the first L sequence numbers of the first sending window has been successfully received by the terminal device.
  • L is a positive integer
  • the determined starting sequence number of the second sending window is equal to the sequence number corresponding to the L+1th data of the first sending window
  • L may also be equal to N.
  • method 200 can be understood as a possible implementation of method 100.
  • the first network device sends a second feedback message to the second network device (anchor gNB).
  • the second feedback message indicates whether the terminal device has successfully or unsuccessfully received the first downlink data.
  • the second network device can decide how to adjust the PDCP sending window based on the feedback message.
  • the embodiment of the present application enables the anchor point gNB to obtain the RLC status of the terminal device through interaction between network devices, so that it can push data based on the data successfully received by the terminal device. PDCP sending window to reduce packet loss rate.
  • FIG. 5 shows a schematic diagram of the data transmission method 110 provided by this application.
  • the second network device sends second indication information to the terminal device.
  • the terminal device receives the second indication information from the second network device.
  • the second indication information is used to indicate whether to allow/use the small data packet during transmission. Data loss can be avoided.
  • the second indication information may be carried in the RRC release message, or may also be carried in other messages, which is not limited in this application.
  • the RRC release message carries a displayed indication information, which can instruct the terminal device to enter the RRC inactive state.
  • the second indication information can also be understood as being used to indicate to the terminal device that if SDT fails, such as cell reselection, during the subsequent SDT process, the second network device supports a mechanism to avoid the loss of uplink data. Specifically, this mechanism Subsequent steps in method 110 are included.
  • the second instruction information here can be expressed as a flag to enable avoidance of data loss, or it can also be other expression methods with similar functions, which is not limited by this application.
  • S112, S113 and S114 can be implemented in multiple ways. For example, in scheme 1, S112-a, S113 is S113-a, and S114 is S114-a, or in scheme 2, S112 is S112-b-1 and S112-b. -2, S113 is S113-b-1 and S113-b-2, and S114 is S114-b.
  • the second network device directly sends the fourth downlink data to the terminal device, and accordingly, the terminal device directly receives the fourth downlink data from the second network device.
  • the terminal device directly feeds back the status report corresponding to the fourth downlink data to the second network device.
  • the second network device directly receives the status report corresponding to the fourth downlink data from the terminal device.
  • the first network device is the anchor gNB.
  • the second network device sends the fourth downlink data to the terminal device indirectly (through other devices), and accordingly, the terminal device receives the fourth downlink data from the second network device indirectly (through other devices).
  • the terminal device indirectly (through other devices) feeds back the status report corresponding to the fourth downlink data to the second network device.
  • the second network device indirectly (through other devices) receives the status report corresponding to the fourth downlink data from the terminal device.
  • the first network device is not the anchor gNB.
  • the second network device can send the fourth downlink data through the third network device.
  • the terminal device may also first feed back the second status report to the third network device, and then the third network device sends the first status report to the second network device based on the second status report.
  • the third network device and the second network device may be two gNBs in the same RNA, and the second network device saves the context of the terminal device.
  • the third network device may be the receiving gNB
  • the second network device may be the previous serving gNB.
  • a possible implementation method please refer to the corresponding description in 500.
  • the subsequent steps of Solution 2 involve the terminal device performing cell reselection and reselecting to the cell of the first network device.
  • the first network device can be the receiving gNB
  • the second network device can be the previous service. gNB.
  • the third network device here is called the previous receiving gNB in the method 500
  • the first network device is called the receiving gNB.
  • the second network device sends fourth downlink data to the terminal device.
  • the terminal device receives the fourth downlink data from the second network device, and the fourth downlink data is small data.
  • the terminal device sends a first status report to the second network device.
  • the second network device receives the first status report from the terminal device.
  • the first status report is used to indicate that the fourth downlink data has not been successfully received.
  • the first status report here may correspond to the radio link control layer.
  • S113-a does not limit the first status report to indicating unsuccessfully received downlink data to the second network device.
  • the unsuccessful reception of the fourth downlink data is used as an example to introduce how the embodiment of the present application Reduce packet loss rate.
  • the first status report may also indicate that the terminal device successfully receives downlink data B, and the downlink data B is also sent to the terminal device by the second network device.
  • the first network device sends the first instruction information to the terminal device.
  • the terminal device receives the first instruction information from the first network device.
  • the first instruction information is used to instruct the first network device to support small data packets. Avoid data loss during transfer.
  • method 110 may also include the terminal device performing cell reselection to the cell where the first network device is located.
  • the first indication information can be understood as, in the subsequent steps of S114-a, if the terminal device wants to communicate with the network device through the first network device, the first network device can support avoiding the connection between the terminal device and the network before SDT fails. Data transferred between sides is lost.
  • the first network device when the first network device supports avoiding data loss during small data packet transmission, the first network device sends the first indication information to the terminal device. For example, when the first network device does not support avoiding data loss during small data packet transmission, the first network device may send indication information A to the terminal device, and the indication information A is used to indicate that data loss during small data packet transmission is not supported. Data loss is avoided during packet transmission, or the first network device does not send the first indication information or indication information A.
  • the terminal device can perform cell reselection again, reselect to a cell of other network devices, and repeat steps similar to S114-a; or, the terminal device can enter the RRC idle state, and optionally, the terminal device initiates Recovery process for non-SDT processes.
  • the first network device may obtain the subscription data of the terminal device according to the identifier carried by the terminal device and send a second request message to the second network device, where the second request message is used to request to obtain the terminal device.
  • the context of the device the second request message includes indication information for indicating small data packet transmission; the first network device receives a second response message from the second network device, the second response message includes Instructions for performing anchor relocation. It can be understood that the anchor point is relocated from the second network device to the first network device, and the protocol stack is migrated from the second network device to the first network device, for example, as shown in (b) in FIG. 3 .
  • the second response message includes The context of the terminal device. Then the first network device performs an SDT process with the terminal device according to the context of the terminal device, and the first network device saves the context of the terminal device at the PDCP layer.
  • the first network device receives fourth indication information from the second network device.
  • the second network device receives fourth indication information from the first network device.
  • the fourth indication information is used to indicate that the terminal device has not Successfully received the fourth downlink data.
  • the first network device determines the sending window of PDCP according to the fourth indication information.
  • the method of determining the PDCP transmission window may refer to the description in S414.
  • the fourth indication information is carried in the second response message, or the fourth indication information is implicitly indicated by S115, or the fourth indication information is transmitted together with the fourth downlink data.
  • the second network device sends fourth downlink data to the third network device.
  • the third network device receives the fourth downlink data from the second network device, and the fourth downlink data is small data.
  • the third network device sends fourth downlink data to the terminal device, and accordingly, the terminal device receives the fourth downlink data from the third network device.
  • the terminal device sends a second status report to the third network device.
  • the third network device receives the second status report from the terminal device.
  • the second status report is used to indicate that the fourth downlink data has not been successfully received. .
  • the second status report here may correspond to the radio link control layer.
  • S114-b for details, please refer to the description of S114-a in Solution 1. The difference is that the optional steps after S114-a are different from the optional steps after S114-b.
  • the first network device may obtain the subscription data of the terminal device according to the identifier carried by the terminal device and send a third request message to the second network device, where the third request message is used to request to obtain the terminal device.
  • the context of the device the third request message includes instruction information for indicating small data packet transmission; the first network device receives a third response message from the second network device, the third response message includes Instructions to not perform anchor relocation.
  • the second network device is still the anchor gNB, the RLC, MAC, and PHY in the protocol stack are migrated to the first network device, and PDCP and SDAP are still on the second network device, such as (a) in Figure 3 Show.
  • the third response message includes the SDT context.
  • SDT context please refer to S515 of the method 500.
  • S114 precedes S113-b-2, or may also precede S113-b-2.
  • the third network device sends the first status report to the second network device.
  • the second network device receives the first status report from the third network device.
  • the first status report includes instructions for instructing the terminal device. Indication information indicating that the fourth downlink data was not successfully received.
  • the second status report here may correspond to the packet data aggregation layer.
  • S113-b-1 and S113-b-2 may refer to S103 and S104 in the method 100 respectively.
  • step 1 the second network device sends a fourth request message to the third network device, and accordingly, the third network device receives the fourth request message from the first network device.
  • the fourth request message is used to request a fourth downlink data status report.
  • the first status report in S113-b-2 is carried in the response message of the request message.
  • step 1 may be performed before the terminal equipment cell is reselected to the cell of the first network equipment, or after the terminal equipment cell is reselected to the cell of the first network equipment.
  • the third request message in S114 may be understood as a trigger condition that triggers the second network device to perform step 1.
  • the second network device may also determine the PDCP transmission window after cell reselection based on the first status report. For details, see the example given in S513.
  • the second network device sends fourth downlink data to the first network device.
  • the terminal device receives the fourth downlink data from the first network device.
  • the first network device sends fourth downlink data to the terminal device, and accordingly, the terminal device receives the fourth downlink data from the first network device.
  • the second network device retransmits the fourth downlink data to the terminal device through the first network device.
  • the terminal equipment will enter the RRC idle state and will no longer transmit data packets, and packet loss is likely to occur.
  • the unsuccessfully received data is retransmitted to the terminal device, so that the terminal device can obtain the data that was successfully received before SDT failed, thereby reducing the packet loss rate in the SDT process.
  • the third network device may release the link with the terminal device and stop communicating with the terminal device. It should be noted that there is no restriction here that the next step of the third network device after receiving the fourth request message is to release the link with the terminal device and stop communicating with the terminal device.
  • method 400 can be understood as a possible implementation of solution 1 of method 110
  • method 500 can be understood as a possible implementation of solution 2 of method 110.
  • Figure 6 shows a schematic diagram of the data transmission method 120 provided by this application.
  • the second network device sends second indication information to the terminal device.
  • the terminal device receives the second indication information from the second network device.
  • the second indication information is used to indicate whether to allow/use the small data packet during transmission. Data loss can be avoided.
  • the terminal device sends fourth uplink data to the second network device.
  • the second network device receives the fourth uplink data from the terminal device, and the fourth uplink data is small data.
  • the second network device sends a third status report to the terminal device.
  • the terminal device receives the third status report from the second network device.
  • the third status report includes at least one of the following indication information: used to indicate success.
  • Instruction information for receiving the first uplink data is used to indicate that the second uplink data has not been successfully received.
  • the fourth uplink data includes the first uplink data and the second uplink data.
  • the terminal device can determine which data in the fourth uplink data has been successfully received and which data has not been successfully received according to the third status report.
  • the third status report here may correspond to the radio link control layer.
  • the first network device sends the first indication information to the terminal device.
  • the terminal device receives the first indication information from the first network device.
  • the first indication information is used to instruct the first network device to support the small data packet transmission process. to avoid data loss.
  • the second network device sends the first uplink data to the first network device.
  • the first network device receives the first uplink data from the second network device.
  • the first uplink data is data successfully received by the second network device.
  • the first uplink data is small data.
  • the second network device since the anchor point is relocated to the first network device, the second network device also sends data that has been successfully received from the terminal device before the SDT fails to the first network device.
  • the terminal device sends second uplink data to the first network device.
  • the first network device receives the second uplink data from the terminal device.
  • the second uplink data is data from the terminal device that the second network device fails to receive.
  • the second uplink data is small data.
  • the terminal device retransmits the data that the second network device failed to receive to the first network device according to the third status report received in S123. It can be understood that through S125 and S126, the first network device can successfully receive the fourth uplink data sent by the terminal device to the second network device in S122.
  • method 300 can be understood as a possible implementation of method 120.
  • the terminal equipment when cell reselection occurs on the terminal equipment, the terminal equipment will enter the RRC idle state and will no longer transmit data packets, and packet loss is likely to occur.
  • the terminal device after SDT fails, the terminal device retransmits the data that was not successfully received by the second network device, and sends the data that has been successfully received from the terminal device to the first network device through the second network device, so that the first The network device can obtain the data sent by the terminal device to the second network device before SDT failed, thereby reducing the packet loss rate during the SDT process.
  • Figure 7 shows a schematic diagram of the data transmission method 200 provided by this application.
  • the method 200 is introduced below by taking the first network device as the receiving gNB (receiving gNB), the second network device as the last serving gNB (last serving gNB), and the first downlink data as the first downlink SDT data.
  • the UE may move out of the coverage area of the second network device and access the network through the first network device.
  • the UE initiates the SDT recovery process, and the first network device requests the context of the UE from the second network device.
  • the first network device provides the RLC status to the second network device so that the second network device adjusts the PDCP sending window according to the RLC status.
  • the protocol stack distribution of the UE, the first network device and the second network device see (a) in Figure 3 .
  • the terminal device sends an RRC resume request (RRC resume request) message and uplink SDT data (UL SDT data) to the first network device.
  • RRC resume request RRC resume request
  • uplink SDT data UL SDT data
  • the first network device receives the RRC resume request and uplink SDT data 01 from the terminal device.
  • the first network device caches the uplink SDT data.
  • uplink SDT data in S201 can be replaced with uplink SDT signaling (UL SDT signaling).
  • uplink SDT signaling UL SDT signaling
  • the first network device sends a retrieve context request (retrieve UE context request) message to the second network device.
  • the second network device receives the context request message from the first network device, and the request message includes SDT indication information ( SDT indicator).
  • the second network device determines not to perform anchor point relocation.
  • the second network device may determine not to perform anchor point relocation based on information such as its own load, or based on information received from the first network device.
  • the second network device sends an SDT context transfer message to the first network device.
  • the first network device receives the SDT context transfer message from the second network device.
  • the message includes the SDT context and the downlink data forwarding proposal. (DL dataforwardingproposal) and DRB level uplink transport network layer information (DRB level DL transport network layer information).
  • the message indicates that the second network device does not perform anchor relocation.
  • the second network device also sends an RLC configuration to the first network device.
  • the first network device receives an RLC configuration from the second network device, the RLC configuration corresponding to not performing anchor point relocation.
  • the second network device also sends the uplink data forwarding tunnel address to the first network device.
  • the first network device receives the uplink data forwarding tunnel address from the second network device.
  • the first network device may forward the uplink data received from the UE to the second network device according to the uplink data forwarding tunnel address.
  • the first network device sends XN-U ADDRESS INDICATION to the second network device to indicate the downlink data forwarding tunnel address.
  • the first network device receives the uplink address from the first network device.
  • Address indication information which includes DRB-level uplink transmission network layer information.
  • the second network device may send the downlink data to be sent to the UE to the first network device according to the downlink data forwarding tunnel address, and then the first network device forwards the downlink data to the UE.
  • the first network device uses the uplink data forwarding tunnel address to send uplink SDT data to the second network device.
  • the second network device receives the uplink SDT data from the first network device.
  • the uplink data forwarding tunnel address here may be received in S204.
  • the second network device sends uplink SDT data to the UPF.
  • the UPF receives the uplink SDT data from the second network device.
  • the UPF sends the second downlink SDT data to the second network device, and accordingly, the second network device receives the second downlink SDT data from the UPF.
  • the second network device in S209 processes the second downlink SDT data and obtains the PDCP PDU including the first downlink SDT data; when S208 is not executed.
  • the first downlink SDT data in S209 may be cached internally by the second network device.
  • the second network device uses the downlink data forwarding tunnel address (received in S205) to send the PDCP PDU including the first downlink SDT data to the first network device.
  • the first network device receives the PDCP from the second network device. PDU.
  • the first network device processes the PDCP PDU and obtains an RLC PDU, which includes the first downlink SDT data.
  • the first network device sends the RLC PDU to the UE, and accordingly, the UE receives the RLC PDU from the first network device.
  • the UE sends the RLC status of the RLC PDU to the first network device.
  • the first network device receives the RLC status from the UE.
  • the RLC status is used to indicate successful reception or unsuccessful reception of the first downlink SDT data.
  • the UE successfully receives the first SDT data but fails to receive the second SDT data.
  • the UE may report the RLC status to the first network device by sending an RLC feedback (feedback) message.
  • RLC feedback message ACK indicates successful reception of the first downlink SDT data
  • non-acknowledgment negative acknowledgment, NACK indicates unsuccessful reception of the first downlink SDT data.
  • NACK negative acknowledgment
  • the RLC status here can be understood as a specific example of the first feedback message in the method 100.
  • the first network device sends the RLC status of the PDCP PDU to the second network device.
  • the second network device receives the RLC status from the first network device.
  • the RLC status here can be understood as a specific example of the second feedback message in the method 100.
  • the RLC state can carry the PDCP SN of the first downlink SDT data.
  • the RLC status may also carry an RB identifier. It should be understood that the PDCP SN of the downlink SDT data carried by the same RB may be the same, and the RB identifier carried can more accurately identify the first downlink SDT data.
  • the RLC status is transmitted through a control plane message.
  • the first network device may report the RLC status to the first network device by sending an RLC feedback message.
  • RLC feedback message ACK indicates that the UE successfully received the first downlink SDT data
  • NACK indicates that the UE failed to receive the first downlink SDT data. Receive the first downlink SDT data.
  • the first network device sets a timer. When the timer expires, the first network device feeds back the RLC status to the second network device, for example, performs S212.
  • the timer may be started after the first network device performs S211, or alternatively, It may be started after the first network device receives other RLC status reports.
  • the timing duration of the timer may be determined by the first network device. For example, other RLC status reports here may indicate that the third downlink SDT data is successfully received, and the third downlink SDT data is different from the first downlink SDT data.
  • the window push timer is at the anchor point gNB (the second network device in method 200). Its function is that when the window push timer times out, the anchor gNB will push the PDCP sending window.
  • the timer here is not on the anchor point gNB, but on the first network device. The function of this timer is that when the timer times out, the first network device will feed back the RLC status to the second network device.
  • the terminal device sends the RLC status of one or more RLC PDUs to the first network device, and accordingly, the first network device receives the RLC status of the one or more RLC PDUs from the terminal device.
  • the first network device determines that the terminal device has successfully received M PDCP PDUs based on the RLC status of the one or more RLC PDUs.
  • M ⁇ N or in other words, the first network device determines based on the RLC status of the one or more RLC PDUs.
  • the first threshold is N
  • the first network device sends the RLC status of N PDCP PDUs to the second network device.
  • N is a positive integer.
  • the N here may be indicated by the second network device, and the N here may be understood as a threshold, such as the first threshold.
  • the second network device may indicate to the first network device in step S204.
  • implementation method 2 can reduce signaling overhead.
  • the PDCP SNs of the N PDCP PDUs are consecutive.
  • the sending window when the second network device sends the first SDT data is [1,99], N is 3, and the PDCP SN of the first SDT data is 3.
  • the one or more RLC statuses are also used to indicate the success of the terminal device.
  • the PDCP SN of SDT data A is 2, and the PDCP SN of SDT data B is 1, then the RLC status indication sent by the first network device to the second network device indicates that N PDCPs were successfully received. PDU.
  • the case where the SNs of the PDCP PDUs sent by the first network device to the second network device are continuous may be that the first network device determines that the terminal device successfully received 0, 1, 2, 3, and 4 based on the RLC status of the multiple RLC PDUs. Then the first network device can adjust the starting SN of the PDCP sending window to 5 in S213.
  • S213 The second network device pushes the PDCP sending window according to the RLC status received in S212.
  • the PDCP sending window before executing S213 is called the first sending window
  • the PDCP sending window after executing S213 is called the second sending window.
  • the first sending window includes the PDCP SN of the first SDT data, for example, before pushing
  • the sending window is [1,99]
  • the PDCP SN of the first SDT data before pushing is 3.
  • the second network device executes S213, it needs to determine how many bits to push the PDCP transmission window forward. In other words, it needs to determine the starting SN of the pushed PDCP transmission window.
  • the starting SN here may be the data whose PDCP SN is ranked first among the data that has not been successfully received by the terminal device in the first sending window.
  • the PDCP SN in [1,99] is 4 respectively. If the data of 6-8 and 10-99 is not successfully received by the terminal device, the starting SN can be 4. Alternatively, the starting SN here may be the next PDCP SN of the consecutive data of the first L PDCP SNs among the data successfully received by the terminal device in the first sending window. For example, in [1,99], the data whose PDCP SNs are 1, 2, 3, 5, 6, and 7 are successfully received by the terminal device, and the starting SN can be 4.
  • the second terminal device may determine the range of the PDCP sending window, that is, the starting SN and the ending SN of the sending window.
  • the end SN of the transmission window can be calculated in the following way: the sum of the starting SN and the length of the transmission window is modulated by the length of the SN, and the remainder is the end SN.
  • the starting SN of the PDCP sending window is 5.
  • the length of the sending window is 4 bits and the length of the SN is 8 bits.
  • the sum of the starting SN and the length of the sending window is 9. 9 pairs
  • the remainder of 8 is 1, then the last SN is 1 of the next SN period.
  • the PDCP SN mentioned here can also be identified in binary, 0 can be represented as 00001, 1 can be represented as 0001, 2 can be represented as 0010, 3 can be represented as 0011, and 4 can be represented as 0100.
  • the PDCP SNs involved in this application can be expressed in the above manner, and will be explained uniformly here, and will not be described in detail in other places.
  • the second network device sends a failure message to obtain the UE context to the first network device.
  • the first network device receives a failure message to obtain the UE context from the second network device.
  • this message may be carried in an RRC release message.
  • S215 The first network device sends an RRC release message to the terminal device.
  • the terminal device receives the RRC release message from the first network device. Subsequently, the terminal device terminates the SDT process.
  • the first network device sends an RLC status report to the second network device (anchor gNB)
  • the second network device can decide how to adjust the PDCP transmission window based on the RLC status of the UE, thereby
  • the embodiment of this application provides a solution for when the anchor gNB pushes the PDCP window.
  • Figure 8 shows a schematic diagram of the data transmission method 300 provided by this application.
  • the first network device is the receiving gNB (receiving gNB)
  • the second network device is the previous serving gNB (last serving gNB)
  • the first uplink data is data 1 and 3
  • the second uplink data is data 2 and 4.
  • the third uplink data is data 5, 6, 7, and 8
  • the fourth uplink data is uplink SDT data as an example to introduce method 300.
  • the UE performs cell reselection after sending uplink data to the second network device, and reselects the cell to the first network device.
  • the UE initiates the SDT recovery process, and the first network device requests the context of the UE from the second network device.
  • the second network device decides to perform anchor point relocation
  • the second network device provides the RLC status to the first network device, so that the first network device adjusts the PDCP receiving window according to the RLC status, and the first network device can successfully receive the UE Retransmitted uplink data reduces the packet loss rate of uplink data.
  • the protocol stack distribution of the UE, the first network device and the second network device can be seen in (b) in Figure 3 .
  • the second network device sends an RRC release message to the UE.
  • the UE receives the RRC release message from the second network device.
  • the message includes second indication information, and the second indication information is used to indicate allowing/enabling data loss avoidance during the SDT process.
  • the second indication information can also be understood as indicating to the UE that during the subsequent SDT process, if cell reselection occurs, the second network device supports a mechanism to avoid the loss of uplink data.
  • the mechanism includes steps S302-S319. .
  • the second instruction information here can be expressed as a flag to enable avoidance of data loss.
  • the UE initiates the SDT process, and the UE sends an RRC resume request 1 (RRC resume request) message to the second network device.
  • the second network device receives the RRC resume request 1 message from the UE.
  • the RRC recovery request 1 message includes a first recovery (resume) message authentication code-integrity (message authentication code-integrity, MAC-I).
  • the UE and the first network device start the SDT failure detection timer. If the failure detection timer times out, the UE's RRC enters the idle state, and then initiates a non-SDT recovery process. Therefore, the SDT failure detection timer here is different from the window push timer in the technical terminology section above.
  • the UE sends uplink SDT data to the second network device.
  • the second network device receives the uplink SDT data from the UE.
  • the uplink SDT data includes data 1, 2, 3, and 4. Among them, 1, 2, 3, and 4 are the PDCP SNs of the uplink SDT data respectively.
  • the uplink SDT data in S303 can be sent together with the RRC recovery request message 1 in S302.
  • the uplink SDT data is carried in the RRC recovery request message 1, and the uplink SDT data can be sent together with the RRC recovery request message 1 in S302. Can also be sent separately.
  • the second network device sends an RLC status report to the UE.
  • the UE receives the RLC status report from the second network device, and the report indicates successful reception or unsuccessful reception of the uplink SDT data.
  • the second network device successfully receives the first SDT uplink data but fails to receive the second SDT uplink data.
  • the report may indicate that the first SDT uplink data was successfully received (the SN of the first data is x, x is a natural number), but the second SDT uplink data was not successfully received (the SN of the second SDT uplink data is x+1).
  • the report indicates that data 1, 3 were successfully received; data 2, 4 were not successfully received.
  • S305 The UE determines that SDT fails. For example, the UE performs cell reselection and reselects the cell of the first network device.
  • the first network device sends the system information block 1 to the UE.
  • the UE receives the system information block 1 from the first network device.
  • the system information block 1 carries the SDT configuration and the first indication information.
  • the SDT configuration is used to indicate Time-frequency resources used for random access of SDT.
  • the first indication information is used to indicate a mechanism to support data loss avoidance in the SDT process.
  • the mechanism includes S307-S319.
  • the first indication information here can also be carried in other messages and sent, and this application does not limit this.
  • the first instruction information here can be expressed as support indication for avoidance of data loss.
  • the UE and the first network device restart the SDT failure detection timer.
  • system information block 1 does not carry the first indication information, or the system information block 1 carries another indication information, and the other indication information is used to indicate that avoiding data loss is not supported during the SDT process, then The UE will enter the idle state or continue cell reselection, that is to say, subsequent steps S307-S319 will not be executed.
  • the UE sends the RRC recovery request 2 message to the first network device.
  • the first network device receives the RRC recovery request 2 message from the UE.
  • the message includes the second resume MAC-I, the second resume MAC-I and First resume MAC-I is different.
  • S308 The first network device sends an obtain context request message to the second network device.
  • the second network device receives the obtain context request message from the first network device.
  • S309 The second network device determines to perform anchor point relocation.
  • the second network device may determine to perform anchor point relocation based on information such as its own load, or based on information received from the first network device.
  • the second network device sends a retrieve UE context response message to the first network device.
  • the first network device receives the retrieve UE context response message from the second network device.
  • the response message includes a hyper frame number (HFN) and PDCP SN.
  • the PDCP SN here is used to determine the PDCP reception window.
  • the HFN here is used to encrypt data transmitted between the network and the terminal device.
  • the HFN and SN here may be the HFN and PDCP SN through which the network receives data from the terminal device.
  • the response The information includes the HFN and PDCP SN of the second SDT uplink data.
  • the message instructs the second network device to perform anchor relocation.
  • the first network device may determine the PDCP reception window based on the response information. Determining the PDCP receiving window can be understood as determining the range of the PDCP receiving window, that is, the starting SN and the ending SN of the PDCP receiving window. Among them, the starting SN of the receiving window is the PDCP SN included in the response message. The end SN of the receive window can be calculated in the following way: the sum of the starting SN and the length of the receive window is modulated by the length of the SN, and the remainder is the end SN.
  • the first SN in the receiving order can be used as the SN of the PDCP receiving window.
  • the response message includes the PDCP SNs of the second SDT uplink data, which are 2 and 4.
  • the starting SN of the PDCP receiving window is 2.
  • the length of the receiving window is 4 bits, and the length of the SN is 8 bits, among which, the sum of the starting SN and the length of the receiving window is 6, and the modulus of 6 to 8 is 6, then the end SN is 6 of the current SN period.
  • the second network device when SDT fails, the second network device sends a status report to the first network device (anchor gNB).
  • the first network device decides how to adjust the PDCP reception window based on the status, and the adjusted PDCP reception window. Therefore, the embodiment of the present application provides a solution for when the anchor gNB pushes the PDCP window.
  • the first network device sends a path switch request (pathswitchrequest) message to the AMF.
  • the AMF receives the path switch request message from the first network device.
  • the path switching request message is used to request the AMF to switch the connection between the UPF and the second network device to the connection between the UPF and the first network device.
  • the downlink data to be sent by the network to the UE is directly sent by the UPF to the first network device instead of being sent by the UPF to the second network device.
  • the AMF sends a path switch acknowledgment message to the first network device.
  • the first network device receives the path switch acknowledgment message from the AMF.
  • S314 The second network device uses the downlink forwarding tunnel address (received in S313) to forward (forwarding) the first SDT uplink data to the first network device.
  • the first network device receives the first forwarded data from the second network device.
  • SDT uplink data For example, the second network device sends a PDCP SDU to the first network device, and the PDCP SDU includes data 1, 3.
  • the second network device forwards the first SDT uplink data to the first network device, it may implicitly indicate that the first SDT uplink data is successfully received. Alternatively, the second network device may also explicitly indicate to the first network device that the first SDT uplink data is successfully received. For example, the second network device may send the content indicated in the status report sent to the UE in S304 to the first network. equipment.
  • the second network device forwards the successfully received uplink data to the first network device, which can save signaling overhead.
  • the UE retransmits the second SDT uplink data to the first network device.
  • the first network device receives the second SDT uplink data from the UE. Since the SN of the second SDT uplink data (data 2, 4) is within the above-mentioned receiving window, the data is valid data. Then the first network device sorts the second SDT uplink data and the first SDT uplink data according to the PDCP SN.
  • the first network device delivers in-order delivery to the protocol layer above PDCP.
  • the UE Because during the SDT process, when the UE undergoes cell reselection, the UE will enter the RRC idle state and will no longer transmit data packets, and packet loss is likely to occur. In this embodiment of the present application, after cell reselection, if the UE fails to retransmit the The data received by the second network device can reduce the packet loss rate.
  • the first network device forwards the uplink SDT data (data 1, 2, 3, 4) to the AMF in order.
  • the AMF receives the uplink SDT data from the first network device.
  • the first network device sends an RRC release message to the UE, and accordingly the UE receives the RRC release message from the first network device.
  • the UE terminates the SDT process.
  • the first network device sends a UE context release message to the second network device.
  • the second network device accepts the UE context release message from the first network device.
  • the second network device releases the UE context and terminates communication with the UE.
  • the UE may also send third uplink SDT data to the first network device, for example, data with PDCP SN numbers 5, 6, 7, and 8.
  • the first network device receives the third uplink SDT data from the UE.
  • the key used when the UE sends data 1, 2, 3, and 4 to the second network device in S303 is different from the key used when the UE sends data 5, 6, 7, and 8 to the first network device in S315.
  • Figure 9 shows a schematic diagram of the data transmission method 400 provided by this application.
  • the first network device is the receiving gNB (receiving gNB)
  • the second network device is the previous serving gNB (last serving gNB)
  • the fourth downlink data is the second downlink SDT data (data 2 and 4)
  • the sixth The downlink data is data 5, 6, 7, and 8 as an example to introduce method 400.
  • the UE performs cell reselection after receiving downlink data from the second network device, and reselects the cell of the first network device.
  • the UE initiates the SDT recovery process, and the first network device requests the context of the UE from the second network device.
  • the second network device decides to perform anchor point relocation, it feeds back the RLC status to the first network device, so that the first network device adjusts the PDCP sending window according to the RLC status.
  • the second network device retransmits the data that the UE failed to receive to the first network device, and the first network device sends the retransmitted data to the UE, so as to reduce the packet loss rate of downlink data.
  • the protocol stack distribution of the UE, the first network device and the second network device can be seen in (b) in Figure 3 .
  • S401-S402 please refer to the description of S301-S302 for details.
  • the second network device sends downlink SDT data to the UE, and accordingly, the UE receives the downlink SDT data from the second network device.
  • the downlink SDT data includes data 1, 2, 3, and 4. Among them, 1, 2, 3, and 4 are the PDCP SNs of the downlink SDT data respectively.
  • the UE sends an RLC status report to the second network device.
  • the second network device receives the RLC status report from the UE.
  • the UE successfully receives the first downlink SDT data but fails to receive the second downlink SDT data.
  • the report may indicate that the first downlink SDT data was successfully received (for example, the SN of the first data is x, x is a natural number), and the second downlink SDT data was not successfully received (for example, the SN of the second downlink SDT data is x+1).
  • the report indicates that data 1, 3 were successfully received; data 2, 4 were not successfully received.
  • S405-S409 please refer to the description of S305-S309 for details.
  • the second network device sends a retrieve UE context response message to the first network device.
  • the first network device receives the retrieve UE context response message from the second network device.
  • S414 The second network device forwards the second downlink SDT data to the first network device according to the downlink forwarding tunnel address provided in S413.
  • the first network device receives the second downlink SDT data from the second network device.
  • the second network device forwards the second downlink SDT data to the first network device, it may implicitly indicate that the first downlink SDT data was unsuccessfully received. Alternatively, the second network device may also explicitly indicate to the first network device that the The second downlink SDT data was unsuccessfully received. For example, the second network device sends an RLC status report to the first network device. The status report is used to indicate that the UE successfully received the first downlink SDT data and failed to receive the second downlink SDT data. , the status report is determined based on the RLC status report received by the second network device from the UE in S404.
  • the first network device may determine the PDCP sending window based on the PDCP SN of the second downlink SDT data.
  • the method of determining the PDCP sending window can refer to the description of determining the PDCP receiving window in S310. The difference is that the receiving window is replaced with the sending window, and the second uplink SDT data is replaced with the second downlink SDT data.
  • the second network device when SDT fails, the second network device sends a status report to the first network device (anchor gNB), and the first network device decides how to adjust the PDCP sending window based on the status. Therefore, the embodiment of this application is useful for the anchor point.
  • the solution is given when gNB pushes the PDCP window.
  • the first network device retransmits the second downlink SDT data to the UE.
  • the UE receives the second downlink SDT data from the first network device. Since the SN of the second downlink SDT data (data 2, 4) is within the above-mentioned transmission window, the data is valid data. Then the UE sorts the second downlink SDT data and the first downlink SDT data according to the PDCP SN.
  • the UE delivers in-order delivery to the protocol layer above PDCP.
  • the anchor point gNB (first network device) retransmits data that has not been successfully received by the UE, which can reduce the packet loss rate.
  • S416-S417 please refer to the description of S317-S318 for details.
  • method 400 may also include:
  • the PDCP SN in the response message can be the next PDCP SN that has not been allocated or used, that is, 5.
  • the first network device may also send the third downlink SDT data to the UE.
  • the PDCP SN of the third downlink SDT data is after the first downlink SDT data and the second downlink SDT data, such as data 5, 6, 7,8.
  • the PDCP SN of the first packet of the third downlink SDT data here is determined based on the PDCP SN that has not been allocated or used as indicated by the response message in S410.
  • FIG 10 shows a schematic flow chart of the data transmission method 500 provided by this application.
  • the second network device is lastservinggNB
  • the first network device is receivinggNB
  • the third network device is the last receiving gNB (lastreceivinggNB).
  • the UE is not within the coverage of the second network device
  • the UE initiates the SDT recovery process to the third network device
  • the third network device requests the context of the UE from the second network device
  • the second network device decides not to execute the anchor. Point redirection
  • the UE and the second network device communicate through the third network device.
  • the first network device sends data 1, 2, 3, 4 to the third network device
  • the third network device sends data 1, 2, 3, 4 to the UE.
  • the UE feeds back a first RLC status report to the third network device.
  • the RLC status report indicates that the UE successfully received data 1 and 3 but failed to receive data 2 and 4.
  • the UE performs cell reselection to the cell where the first network device is located, and initiates an SDT recovery process to the first network device, and the first network device requests the context of the UE from the second network device.
  • the second network device decides not to perform anchor point relocation, the second network device obtains the RLC status report of the UE through the third network device and feeds back to the first network device whether the UE successfully or unsuccessfully receives data, so that The first network device pushes the PDCP send window.
  • the second network device forwards data 2, 4 to the first network device, and the second The network device retransmits data 2 and 4 to the UE, which can reduce the packet loss rate of downlink data.
  • the protocol stack distribution of the UE, the third network device and the second network device can be seen in (a) in Figure 3.
  • the protocol stack distribution of the UE, the first network device and the second network device The protocol stack distribution of network equipment can also be seen in (a) in Figure 3.
  • Figure 11 shows a schematic block diagram of a data transmission method 500 provided by this application.
  • the method 500 will be introduced below by taking the first network device as the fifth downlink data as data 1 and 3, the fourth downlink data as data 2 and 4, and the sixth downlink data as data 5, 6, 7, and 8.
  • S501-S502 please refer to the description of S401-S402 for details. The difference is that: the RRC release message in S401 is replaced with the first RRC release message; the second network device in S402 is replaced with the third network device.
  • S503-S505 please refer to the description of S202-S204 for details. The difference is: replace the first network device in S202-S204 with the third network device, and replace the "get context request message" in S202-S204 with "get context” Request message 1", replace "SDT context” in S202-S204 with "SDT context 1".
  • the second network device sends downlink SDT data to the UE through the third network device.
  • the second network device sends downlink SDT data to the third network device, and accordingly, the third network device receives the downlink SDT data from the second network device.
  • the third network device sends downlink SDT data to the UE, and accordingly, the UE receives the downlink SDT data from the third network device.
  • the downlink SDT data includes data 1, 2, 3, and 4. Among them, 1, 2, 3, and 4 are the PDCP SNs of the downlink SDT data respectively.
  • S507 please refer to the description of S404.
  • the difference is that the second network device in S404 is replaced with a third network device.
  • the second network device does not perform anchor point relocation here, so the PDCP protocol layer is still on the second network device.
  • the PDCP layer includes the context of the UE. Therefore, the first network device sends to the second network device in S510 to obtain the UE. Context Request 2.
  • the second network device sends an RLC status report request message to the third network device.
  • the third network device receives the RLC status report request message from the first network device. This message is used to request the UE's RLC status report.
  • the third network device sends a second RLC status report to the second network device.
  • the second network device receives the second RLC status report from the third network device.
  • the status report needs to indicate the logical channel number of the SDT data. Or RB index, and PDCP SN or RLC SN.
  • the UE successfully receives the first downlink SDT data but fails to receive the second downlink SDT data.
  • the report may indicate successful reception of the first downlink SDT data and unsuccessful reception of the second downlink SDT data. And carry the logical channel number of the first downlink SDT data and the second downlink SDT data or the RB index that carries the first downlink SDT data and the second downlink SDT data, as well as the first downlink SDT data and the second downlink SDT data.
  • PDCP SN or RLC SN may be used to Physical channels.
  • the second network device learns that the UE is reselected to the cell of the first network device.
  • the second network device obtains the RLC status of the UE through S512 and S513, adjusts the PDCP sending window according to the UE's RLC status report, and retransmits the downlink data that the UE failed to receive to the UE through the first network device in subsequent steps.
  • the way in which the second network device adjusts the transmission window of PDCP may refer to the way in which the first network device adjusts the transmission window of PDCP in step S414 of method 400.
  • the UE transmits data to the second network device through the third network device and the first network device successively, and the second network device as the anchor point gNB negotiates the status report between the third network device and the first network device, that is, The status report is obtained from the third network device, and the first network device determines how to adjust the PDCP sending window based on the RLC status provided by the third network device. Therefore, the embodiment of this application provides a solution for when the anchor gNB pushes the PDCP window.
  • the third network device releases the connection with the UE and stops communicating with the UE.
  • S514 may also be performed after S512 and before S513, or may be performed at any step after S513, which is not limited by this application.
  • the second network device sends a retrieve UE context response message to the first network device.
  • the first network device receives the retrieve UE context response message from the second network device.
  • This message can carry PDCP configuration and PDCP sending window information (such as the next sent PDCP SN) and PDCP status report.
  • the PDCP status report is used to indicate that the data has been successfully received by the terminal device.
  • the message indicates that the second network device does not perform anchor relocation.
  • S517 The second network device forwards the downlink data to the first network device according to the downlink forwarding tunnel address provided in S516.
  • the first network device receives the downlink data from the second network device, that is, the above-mentioned second downlink SDT data.
  • the second network device forwards the second downlink SDT data to the first network device, it may implicitly indicate that the first downlink SDT data was unsuccessfully received. Alternatively, the second network device may also explicitly indicate to the first network device that the second downlink SDT data was unsuccessfully received. For example, the second network device sends an RLC status report to the first network device. The status report is used to indicate that the UE is successful. The first downlink SDT data is received, but the second downlink SDT data is not successfully received. The status report is determined based on the second RLC status report received by the second network device from the third network device in S513.
  • the packet loss rate can be reduced by using the UE to retransmit data that was not successfully received by the second network device.
  • the first network device retransmits the second downlink SDT data to the UE.
  • the UE receives the second downlink SDT data from the first network device. Since the SN of the second downlink SDT data (data 2, 4) is within the above-mentioned transmission window, the data is valid data. Then the UE sorts the second downlink SDT data and the first downlink SDT data according to the PDCP SN.
  • the UE delivers in-order delivery to the protocol layer above PDCP.
  • the first network device sends the second RRC release message to the UE through the third network device.
  • the first network device sends a second RRC release message to the third network device, and accordingly, the third network device receives the second RRC release message from the first network device.
  • the third network device sends the second RRC release message to the UE, and accordingly, the UE receives the second RRC release message from the third network device.
  • the terminal device After receiving this message, the terminal device terminates the SDT process.
  • the first network device may also send third downlink SDT data to the UE, the PDCP SN of the third downlink SDT data is after the first downlink SDT data and the second downlink SDT data, for example, data 5, 6, 7, 8.
  • the PDCP SN of the first data packet of the third downlink SDT data here is determined based on the PDCP sending window information in S515.
  • Method 600 can be combined with any one of methods 100 to 120 and methods 200 to 500.
  • the UE has already performed cell reselection. Then in method 600, the UE can count the number of cell reselections during the SDT process. In method 200, the UE does not perform cell reselection. If the UE performs cell reselection in the subsequent SDT process, the number of cell reselections can also be counted according to method 600.
  • Y is a positive integer
  • the UE enters the idle state, or initiates a non-SDT recovery process. Among them, the UE performs a cell reselection, which can be understood as an SDT failure.
  • the UE obtains the default value Y.
  • the preset value Y may be sent by the network device to the UE through an RRC release message.
  • the UE receives the RRC release message from the w network device, which indicates the maximum number of cell reselections Y in the SDT process.
  • the network device here may be the anchor network device in the aforementioned method.
  • the UE initiates an SDT process. During this process, due to mobility, the terminal device may perform cell reselection one or more times, and the UE records the number of cell reselections.
  • a threshold is set for the number of cell reselections for the UE, and the UE counts the number of cell reselections.
  • the cell reselection is stopped or switched to the idle state or a non-SDT recovery process is initiated.
  • FIG. 12 is a schematic diagram of a data transmission device 600 provided by an embodiment of the present application.
  • the device 600 includes a transceiver unit 610, which can be used to implement corresponding communication functions.
  • the transceiver unit 610 may also be called a communication interface or a communication unit.
  • the device 600 may also include a processing unit 620, which may be used for data processing.
  • a processing unit 620 which may be used for data processing.
  • the device 600 also includes a storage unit, which can be used to store instructions and/or data, and the processing unit 620 can read the instructions and/or data in the storage unit, so that the device implements each of the foregoing method embodiments.
  • Actions performed by communication equipment such as terminal equipment and network equipment).
  • the device 600 can be used to perform the actions performed by the communication device (such as a terminal device, or a network device) in each of the above method embodiments.
  • the device 600 can be a communication device (such as a terminal device, or a network device).
  • the transceiver unit 610 is used to perform transceiver-related operations on the side of the communication device (such as a terminal device, or a network device) in the above method embodiment
  • the processing unit 620 is used to perform the communication device in the above method embodiment. Processing-related operations on the side (such as terminal equipment or network equipment).
  • the device 600 is used to perform the actions performed by the terminal device in each of the above method embodiments.
  • the transceiver unit 610 is configured to receive second instruction information from the second network device.
  • the second instruction information is used to instruct to avoid data loss during the transmission of small data packets; and is also configured to receive the fourth downlink data, the fourth downlink data is small data; also used to send indication information indicating that the fourth downlink data has not been successfully received; and also used to receive first indication information from the first network device, the first indication information Used to indicate the first network device Supports avoiding data loss during small data packet transmission; and is also used to receive fourth downlink data from the first network device.
  • the transceiver unit 610 is specifically configured to receive the fourth downlink data from the second network device; the transceiver unit 610 is specifically configured to send a first status report to the second network device, where the first status report includes This instruction message.
  • the transceiver unit 610 is specifically configured to receive the fourth downlink data from the third network device; the transceiver unit 610 is specifically configured to send a second status report to the third network device, where the second status report includes the Instructions.
  • the transceiver unit 610 is also configured to receive a radio resource control release message from the network device.
  • the radio resource control release message includes Y, where Y is the number of cell reselections during small data packet transmission, and Y is a positive integer.
  • the processing unit 620 is used to initiate the small data packet transmission process; the terminal equipment records the number of cell reselections; when the number of cell reselections recorded by the device is ⁇ Y, the processing unit 620 is also used to switch to wireless
  • the resource control idle state, or the transceiver unit 610, is also used to send a recovery request message for non-small data packet transmission to the network device.
  • the transceiver unit 610 is used to receive the second instruction information from the second network device.
  • the second instruction information is used to instruct to avoid data loss during the transmission of small data packets;
  • the transceiver unit 610 is also used to
  • the transceiver unit 610 is also configured to receive a third status report from the second network device, and the third status report includes the following instructions: At least one of the information: indication information indicating successful reception of the first uplink data, indication information indicating unsuccessful reception of the second uplink data, wherein the fourth uplink data includes the first uplink data and the third uplink data. 2.
  • the transceiver unit 610 is also used to receive the first indication information from the first network device, the first indication information is used to instruct the first network device to support avoiding data loss during the transmission of small data packets; the transceiver unit 610: Also used to send the second uplink data to the first network device.
  • the device 600 is configured to perform the actions performed by the first network device in each of the above method embodiments.
  • the transceiver unit 610 is used to receive the first downlink data from the second network device, where the first downlink data is small data; and is also used to send the first downlink data to the terminal device; It is also used to receive a first feedback message from the terminal device, the first feedback message is used to indicate successful or unsuccessful reception of the first downlink data, and the feedback message corresponds to the first protocol layer; A feedback message sends a second feedback message to the second network device. The first feedback message is used to indicate that the first downlink data is successfully received. The second feedback message is used to indicate that the terminal device successfully receives the first downlink data. For downlink data, the second feedback message corresponds to the second protocol layer.
  • the first feedback message includes at least one of the following: the sequence number of the first downlink data in the first protocol layer, the identification of the radio bearer carrying the first downlink data, the The identification of the logical channel of the data
  • the second feedback message includes at least one of the following: the sequence number of the first downlink data in the second protocol layer, the sequence number of the first downlink data in the first protocol layer, The identifier of the radio bearer that carries the first downlink data and the identifier of the logical channel that carries the first downlink data.
  • the processing unit 620 is configured to start a timer according to the first feedback message.
  • the transceiving unit 610 is further configured to send a second feedback message to the second network device according to the first feedback message.
  • the processing unit 620 is specifically configured to determine according to the first feedback message that the terminal device successfully receives M pieces of data of the first protocol layer, where M is a positive integer; when among the M pieces of data, the sequence number of the second protocol layer When the number of consecutive data is greater than or equal to N, the transceiver unit 610 is specifically configured to send a second feedback message to the second network device.
  • the second feedback message is used to indicate that the terminal device successfully received the second protocol layer.
  • N data includes the first downlink data, and N is a positive integer.
  • the first protocol layer is a radio link control layer
  • the second protocol layer is a packet data convergence layer
  • the transceiver unit 610 is also configured to send a first request message to the second network device.
  • the first request message is used to request to obtain the context of the terminal device.
  • the first request message includes a message indicating a small data packet.
  • the transmitted instruction information; the transceiver unit 610 is also configured to receive a first response message from the second network device, where the first response message includes instruction information indicating not to perform anchor point relocation.
  • the transceiver unit 610 is also configured to send first indication information to the terminal device, where the first indication information is used to instruct the first network device to support avoiding data loss during small data packet transmission; the transceiver unit 610, It is also used to receive the fourth downlink data from the second network device.
  • the fourth downlink data is unsuccessfully received by the terminal device.
  • the fourth downlink data is small data.
  • the transceiver unit 610 is also used to send data to the terminal device. Send the fourth downlink data.
  • the transceiver unit 610 is also configured to send a second request message to the second network device.
  • the second request message is used to request to obtain the context of the terminal device.
  • the second request message includes a small data packet indicating The transmitted instruction information; the transceiver unit 610 is also configured to receive a second response message from the second network device, where the second response message includes instruction information for instructing to perform anchor point relocation.
  • the transceiver unit 610 is also configured to send a third request message to the second network device.
  • the third request message is used to request to obtain the context of the terminal device.
  • the third request message includes a message indicating a small data packet.
  • the transmitted instruction information; the transceiver unit 610 is also configured to receive a third response message from the second network device, where the third response message includes instruction information indicating not to perform anchor point relocation.
  • the transceiver unit 610 is also configured to send a radio resource control release message to the terminal device.
  • the radio resource control release message includes Y, where Y is the number of cell reselections during small data packet transmission, and Y is a positive integer.
  • the transceiver unit 610 is configured to send first indication information to the terminal device, where the first indication information is used to instruct the first network device to support avoiding data loss during small data packet transmission; the third A network device receives first uplink data from a second network device.
  • the first uplink data is data successfully received by the second network device.
  • the first uplink data is small data.
  • the transceiver unit 610 is also used to receive data from the second network device.
  • the second uplink data of the terminal device, the second uplink data is the data from the terminal device that was not successfully received by the second network device, and the second uplink data is small data.
  • the transceiver unit 610 is also configured to send a second request message to the second network device.
  • the second request message is used to request to obtain the context of the terminal device.
  • the second request message includes a small data packet indicating The transmission instruction information; the transceiver unit 610 is also configured to receive a second response message from the second network device, where the second response message is used to instruct the second network device to decide to perform anchor point relocation.
  • the device 600 is configured to perform the actions performed by the second network device in each of the above method embodiments.
  • the transceiver unit 610 is configured to send the first downlink data to the first network device. If the downlink data is small data, the first network device is used to send the first downlink data to the terminal device; the transceiver unit 610 is also used to receive a second feedback message from the first network device. The message is used to indicate that the terminal device has successfully received or failed to receive the first downlink data, and the second feedback message corresponds to the second protocol layer; the processing unit 620 is used to determine the first transmission window according to the first transmission window and the second feedback message. Two sending windows. The first sending window contains the sequence number of the first downlink data. When the second feedback message indicates that the first downlink data is successfully received, the second sending window contains the sequence number that has not been sent to the terminal device. The sequence number of the downlink data sent.
  • the sequence number of the first downlink data in the second protocol layer the superframe number of the first downlink data in the second protocol layer, the identification of the radio bearer carrying the first downlink data, The identifier of the logical channel carrying the first downlink data.
  • the processing unit 620 is specifically configured for the second network device to determine according to the second feedback message that the data corresponding to the first L sequence numbers of the first sending window have been successfully received by the terminal device.
  • the second sending window The starting sequence number is equal to the sequence number corresponding to the L+1th data of the first sending window, and L is a positive integer.
  • the second feedback message is used to indicate that the terminal device successfully receives N pieces of data with consecutive sequence numbers of the second protocol layer.
  • the N pieces of data include the first downlink data.
  • the second protocol layer is a packet data convergence layer.
  • the transceiver unit 610 is also configured to receive a first request message from the first network device.
  • the first request message is used to request to obtain the context of the terminal device.
  • the first request message includes a message indicating small data.
  • Instruction information for packet transmission; the transceiver unit 610 is also configured to send a first response message to the first network device, where the first response message includes instruction information indicating not to perform anchor point relocation.
  • the transceiver unit 610 is also configured to send second instruction information to the terminal device, where the second instruction information is used to instruct to avoid data loss during the transmission of small data packets; the transceiver unit 610 is also configured to send the fourth downlink data, the fourth downlink data is small data; the transceiver unit 610 is also used to receive a first status report, the first status report includes indication information indicating that the terminal device has not successfully received the fourth downlink data; the transceiver unit 610 610. Also used to send the fourth downlink data to the first network device.
  • the transceiver unit 610 is specifically configured to send the fourth downlink data to the terminal device; the transceiver unit 610 is specifically configured to receive the first status report from the terminal device.
  • the transceiver unit 610 is also configured to receive a second request message from the first network device.
  • the second request message is used to request to obtain the context of the terminal device.
  • the second request message includes a message indicating small data.
  • Instruction information for packet transmission; the transceiver unit 610 is also configured to send a second response message to the second network device, where the second response message includes instruction information for instructing to perform anchor point relocation.
  • the transceiver unit 610 is specifically configured to send the fourth downlink data to the third network device; the transceiver unit 610 is specifically configured to receive the first status report from the third network device.
  • the transceiver unit 610 is also configured to send a fourth request message to the third network device, where the fourth request message is used to request a status report of the fourth downlink data.
  • the transceiver unit 610 is also configured to receive a third request message from the first network device.
  • the third request message is used to request to obtain the context of the terminal device.
  • the third request message includes a message indicating small data.
  • Instruction information for packet transmission; the transceiver unit 610 is also configured to send a third response message to the first network device, where the third response message includes instruction information indicating not to perform anchor point relocation.
  • the method also includes: a transceiver unit 610, also configured to send a radio resource control release to the terminal device.
  • the radio resource control release message includes Y, Y is the number of cell reselections during the transmission of small data packets, and Y is a positive integer.
  • the transceiver unit 610 is used to send second instruction information to the terminal device.
  • the second instruction information is used to instruct to avoid data loss during the transmission of small data packets;
  • the transceiver unit 610 is also used to receive data from The fourth uplink data of the terminal device, the fourth uplink data is small data;
  • the transceiver unit 610 is also used to send a third status report to the terminal device, the third status report includes at least one of the following indication information: Instruction information used to indicate successful reception of the first uplink data, indication information used to indicate unsuccessful reception of the second uplink data, the fourth uplink data includes the first uplink data and the second uplink data; the transceiver unit 610 also Used to send the first uplink data to the first network device.
  • the transceiver unit 610 is also configured to receive a second request message from the second network device.
  • the second request message is used to request to obtain the context of the terminal device.
  • the second request message includes a message indicating small data.
  • Instruction information for packet transmission; the transceiver unit 610 is also configured to send a second response message to the second network device, where the second response message is used to instruct the second network device to decide to perform anchor point relocation.
  • the device 600 here is embodied in the form of a functional unit.
  • the term "unit” as used herein may refer to an application specific integrated circuit (ASIC), an electronic circuit, a processor (such as a shared processor, a proprietary processor, or a group of processors) used to execute one or more software or firmware programs. processor, etc.) and memory, merged logic circuitry, and/or other suitable components to support the described functionality.
  • ASIC application specific integrated circuit
  • processor such as a shared processor, a proprietary processor, or a group of processors
  • memory merged logic circuitry, and/or other suitable components to support the described functionality.
  • the apparatus 600 can be specifically a terminal device in the above embodiments, and can be used to execute various processes and/or steps corresponding to the terminal device in the above method embodiments, or , the apparatus 600 may be specifically the first network device or the second network device in the above embodiments, and may be used to execute various processes and/or steps corresponding to the first network device or the second network device in the above method embodiments, To avoid repetition, they will not be repeated here.
  • the device 600 of each of the above solutions has the function of realizing the corresponding steps performed by the terminal device in the above method, or the device 600 of each of the above solutions has the function of realizing the corresponding steps of the first network device or the second network device of the above method.
  • the functions described can be implemented by hardware, or can be implemented by hardware executing corresponding software.
  • the hardware or software includes one or more modules corresponding to the above functions; for example, the transceiver unit can be replaced by a transceiver (for example, the sending unit in the transceiver unit can be replaced by a transmitter, and the receiving unit in the transceiver unit can be replaced by a receiving unit. (machine replacement), other units, such as processing units, etc., can be replaced by processors to respectively perform the sending and receiving operations and related processing operations in each method embodiment.
  • transceiver unit 610 may also be a transceiver circuit (for example, it may include a receiving circuit and a transmitting circuit), and the processing unit may be a processing circuit.
  • the device in Figure 12 may be the network element or device in the aforementioned embodiment, or it may be a chip or a chip system, such as a system on chip (SoC).
  • the transceiver unit may be an input-output circuit or a communication interface; the processing unit may be a processor, microprocessor, or integrated circuit integrated on the chip. No limitation is made here.
  • FIG. 13 is a schematic diagram of another data transmission device 700 provided by an embodiment of the present application.
  • the device 700 includes a processor 710 coupled to a memory 720 for storing computer programs or instructions and/or data.
  • the processor 710 is used for executing computer programs or instructions stored in the memory 720, or reading the memory 720. live
  • the stored data is used to execute the methods in each of the above method embodiments.
  • processors 710 there are one or more processors 710 .
  • the memory 720 is integrated with the processor 710, or is provided separately.
  • the device 700 also includes a transceiver 1030, which is used for receiving and/or transmitting signals.
  • the processor 710 is used to control the transceiver 1030 to receive and/or transmit signals.
  • the device 700 is used to implement the operations performed by the terminal device in each of the above method embodiments.
  • the processor 710 is used to execute computer programs or instructions stored in the memory 720 to implement related operations of the terminal device in each of the above method embodiments. For example, the method executed by the terminal device in the embodiment shown in Figure 5 or Figure 6.
  • the apparatus 700 is used to implement the operations performed by the first network device or the second network device in each of the above method embodiments.
  • the processor 710 is used to execute computer programs or instructions stored in the memory 720 to implement related operations of the network device in each of the above method embodiments. For example, the method performed by the network device in the embodiment shown in Figure 5 or Figure 6.
  • processors mentioned in the embodiments of this application may be a central processing unit (CPU), or other general-purpose processor, digital signal processor (DSP), or application-specific integrated circuit (ASIC).
  • ASIC application specific integrated circuit
  • FPGA field programmable gate array
  • a general-purpose processor may be a microprocessor or the processor may be any conventional processor, etc.
  • non-volatile memory can be read-only memory (ROM), programmable ROM (PROM), erasable programmable read-only memory (erasable PROM, EPROM), electrically removable memory. Erase electrically programmable read-only memory (EPROM, EEPROM) or flash memory. Volatile memory can be random access memory (RAM). For example, RAM can be used as an external cache.
  • RAM includes the following forms: static random access memory (static RAM, SRAM), dynamic random access memory (dynamic RAM, DRAM), synchronous dynamic random access memory (synchronous DRAM, SDRAM), Double data rate synchronous dynamic random access memory (double data rate SDRAM, DDR SDRAM), enhanced synchronous dynamic random access memory (enhanced SDRAM, ESDRAM), synchronous link dynamic random access memory (synchlink DRAM, SLDRAM) and direct Memory bus random access memory (direct rambus RAM, DR RAM).
  • the processor is a general-purpose processor, DSP, ASIC, FPGA or other programmable logic device, discrete gate or transistor logic device, or discrete hardware component
  • the memory storage module
  • memories described herein are intended to include, but are not limited to, these and any other suitable types of memories.
  • FIG 14 is a schematic diagram of a chip system 800 provided by an embodiment of the present application.
  • the chip system 800 (or can also be called a processing system) includes a logic circuit 810 and an input/output interface 820.
  • the logic circuit 810 may be a processing circuit in the chip system 800 .
  • the logic circuit 810 can be coupled to the storage unit and call instructions in the storage unit, so that the chip system 800 can implement the methods and functions of various embodiments of the present application.
  • the input/output interface 820 can be an input/output circuit in the chip system 800 to process the chip system 800 Good information is output, or data or signaling information to be processed is input to the chip system 800 for processing.
  • the logic circuit 810 can discover a message to the network device through the input/output interface 820, and the message can be a message that the logic circuit 810 can send according to the input/output interface 820. generated; or the input/output interface 820 may input the first information from the network device to the logic circuit 810 for processing.
  • the logic circuit 810 can send the first information to the terminal device through the input/output interface 820, and the first information can be the logic circuit 810; or the input/output interface 820 can input messages from the terminal device to the logic circuit 810 for processing.
  • the chip system 800 is used to implement the operations performed by the terminal device in each of the above method embodiments.
  • the logic circuit 810 is used to implement the processing-related operations performed by the terminal device in the above method embodiment, such as the processing-related operations performed by the terminal device in the embodiment shown in FIG. 2 or FIG. 3 or FIG. 4; input
  • the /output interface 820 is used to implement the sending and/or receiving related operations performed by the terminal device in the above method embodiment, such as the sending and/or receiving operations performed by the terminal device in the embodiment shown in Figure 2 or Figure 3 or Figure 4. or receive related operations.
  • the chip system 800 is used to implement the operations performed by the network device in each of the above method embodiments.
  • the logic circuit 810 is used to implement processing-related operations performed by the network device in the above method embodiment, such as processing-related operations performed by the network device in the embodiment shown in FIG. 2 or FIG. 3 or FIG. 4; input
  • the /output interface 820 is used to implement the sending and/or receiving related operations performed by the network device in the above method embodiment, such as the sending and/or receiving operations performed by the network device in the embodiment shown in Figure 2 or Figure 3 or Figure 4. or receive related operations.
  • Embodiments of the present application also provide a computer-readable storage medium on which are stored computer instructions for implementing the methods executed by terminal devices or network devices in each of the above method embodiments.
  • the computer program when executed by a computer, the computer can implement the method executed by the terminal device or network device in each embodiment of the above method.
  • Embodiments of the present application also provide a computer program product, which includes instructions.
  • the instructions are executed by a computer, the methods executed by terminal devices or network devices in each of the above method embodiments are implemented.
  • An embodiment of the present application also provides a communication system, which includes the terminal equipment and network equipment in the above embodiments.
  • the system includes the terminal device and the network device in the embodiment shown in Figure 2 or Figure 3 or Figure 4 .
  • the disclosed devices and methods can be implemented in other ways.
  • the device embodiments described above are only illustrative.
  • the division of the units is only a logical function division. In actual implementation, there may be other division methods.
  • multiple units or components may be combined or can be integrated into another system, or some features can be ignored, or not implemented.
  • the coupling or direct coupling or communication connection between each other shown or discussed may be through some interfaces, and the indirect coupling or communication connection of the devices or units may be in electrical, mechanical or other forms.
  • the computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device.
  • the computer may be a personal computer, a server, or a network device.
  • the computer instructions may be stored in or transmitted from one computer-readable storage medium to another, e.g., the computer instructions may be transferred from a website, computer, server, or data center Transmission to another website, computer, server or data center by wired (such as coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (such as infrared, wireless, microwave, etc.) means.
  • the computer-readable storage medium may be any available medium that can be accessed by a computer or a data storage device such as a server, data center, etc. that contains one or more available media integrated.
  • the available media may be magnetic media (such as floppy disks, hard disks, magnetic tapes), optical media (such as DVDs), or semiconductor media (such as solid state disks (SSD)).
  • the aforementioned available media include but Not limited to: U disk, mobile hard disk, read-only memory (ROM), random access memory (RAM), magnetic disk or optical disk and other media that can store program code.

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Abstract

本申请提供了一种数据传输的方法和通信装置，该方法包括：终端设备与网络设备之间进行小数据包传输，第二网络设备通过第一网络设备向终端设备发送第一下行数据，终端设备向第一网络设备反馈成功或未成功接收第一下行数据，第一网络设备向第二网络设备反馈终端设备成功或为成功接收第一下行数据，从而第二网络设备可以根据第一网络设备反馈消息确定第二网络设备与终端设备通信的发送窗口。该方法和装置，可以提高小数据包传输过程中的丢包率。

Description

数据传输的方法和通信装置
本申请要求于2022年4月19日提交中国专利局、申请号为202210410657.X、申请名称为“数据传输的方法和通信装置”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本申请实施例涉及无线通信领域，并且更具体地，涉及一种数据传输的方法和通信装置。
背景技术
终端设备(user equipment，UE)通过一个新基站节点(generation nodeb，gNB)与网络侧通信该gNB还为UE配置一个RAN的通知区域(RAN based notification area，RNA)下移动。UE在该RNA内移动时，可能会离开上一个gNB的覆盖范围，此时如果UE需要与网络侧传输少量数据，可以通过随机接入的方式与该RNA内的其他gNB建立连接，从而与网络侧进行小数据包传输。在该小数据包传输过程中，很可能出现丢包的问题，因此，如何降低丢包率称为亟待解决的问题。
发明内容
本申请提供一种数据传输的方法和通信装置，能够降低小数据包传输过程中的丢包率。
第一方面，提供了一种数据传输的方法，该方法可以由第一网络设备执行，或者，也可以由第一网络设备的组成部件(例如芯片或者电路)执行，本申请对此不作限定。为了便于描述，下面以由第一网络设备执行为例进行说明。
该方法可以包括：第一网络设备接收来自第二网络设备的第一下行数据，该第一下行数据为小数据；该第一网络设备向终端设备发送该第一下行数据；该第一网络设备接收来自该终端设备的第一反馈消息，该第一反馈消息用于指示成功或未成功接收该第一下行数据，该第一反馈消息对应第一协议层；该第一网络设备根据该第一反馈消息向该第二网络设备发送第二反馈消息，该第一反馈消息用于指示成功接收该第一下行数据的情况下，该第二反馈消息用于指示该终端设备成功接收该第一下行数据，该第二反馈消息对应第二协议层。
上述方案，在小数据包传输过程中，通过第一网络设备向第二网络设备发送第二反馈消息，该第二反馈消息指示终端设备成功或未成功接收第一下行数据，使得第二网络设备获取终端设备是否成功接收第一下行数据，从而可以根据终端设备成功接收的数据调整下行数据的发送窗口，减少因第二网络设备无法获知第一下行数据是否被终端设备成功接收而随意调整发送窗口而导致的丢包，从而降低丢包率。
结合第一方面，在第一方面的某些实现方式中，该第一反馈消息包括以下至少一项： 该第一下行数据在该第一协议层的序列号、承载该第一下行数据的无线承载的标识、承载该第一下行数据的逻辑信道的标识，该第二反馈消息包括以下至少一项：该第一下行数据在该第二协议层的序列号、该第一下行数据在该第一协议层的序列号、承载该第一下行数据的无线承载的标识、承载该第一下行数据的逻辑信道的标识。
结合第一方面，在第一方面的某些实现方式中，该方法还包括：该第一网络设备根据该第一反馈消息启动定时器。
结合第一方面，在第一方面的某些实现方式中，该第一网络设备根据该第一反馈消息向该第二网络设备发送第二反馈消息，包括：该定时器超时的情况下，该第一网络设备根据该第一反馈消息向该第二网络设备发送第二反馈消息。
应理解，在定时器的定时时长内，终端设备可能向第一网络设备反馈是否成功接收多个下行数据。上述方案，第一网络设备通过设置定时器，在定时器超时时向第二网络设备反馈终端设备是否成功接收下行数据，相比于每次接收到来自终端设备的反馈消息就向第二网络设备指示该反馈消息中的内容，可以节省信令开销。
结合第一方面，在第一方面的某些实现方式中，该第一网络设备根据该第一反馈消息向该第二网络设备发送第二反馈消息，包括：该第一网络设备根据该第一反馈消息确定终端设备成功接收该第一协议层的M个数据，M为正整数；当该M个数据中，第二协议层的序列号连续的数据的个数大于或等于N时，该第一网络设备向该第二网络设备发送第二反馈消息，该第二反馈消息用于指示该终端设备成功接收该第二协议层的N个数据，该N个数据包括该第一下行数据，该N为正整数。
上述方案，相比于每次接收到来自终端设备的反馈消息就向第二网络设备指示该反馈消息中的内容，可以节省信令开销。另外，第一网络设备给第二网络设备反馈的N个数据的序列号是连续的，可以便于第二网络设备直接根据第二反馈消息将发送窗口往前推动N个序列号，也可以节省第二网络设备缓存数据的功耗。
结合第一方面，在第一方面的某些实现方式中，该第一协议层为无线链路控制层，该第二协议层为分组数据汇聚层。
结合第一方面，在第一方面的某些实现方式中，该方法还包括：该第一网络设备向该第二网络设备发送第一请求消息，该第一请求消息用于请求获取该终端设备的上下文，该第一请求消息包括用于指示小数据包传输的指示信息；该第一网络设备接收来自该第二网络设备的第一响应消息，该第一响应消息包括用于指示不执行锚点重定位的指示信息。
应理解，第一网络设备向第二网络设备请求终端设备的上下文，说明终端设备已经不在第二网络设备的覆盖范围内，而第二网络设备不执行锚点重定向，说明第二网络设备仍然为锚点gNB。上述方案，在不执行锚点重定位的场景下，通过网络设备之间基于第二协议层的交互，使得锚点gNB获知终端设备的第一协议层的状态，便于锚点gNB根据终端设备的第一协议层的状态调整发送窗口，降低丢包率。
结合第一方面，在第一方面的某些实现方式中，该方法还包括：该第一网络设备向该终端设备发送第一指示信息，该第一指示信息用于指示该第一网络设备支持在小数据包传输过程中避免数据丢失；该第一网络设备接收来自第二网络设备的第四下行数据，该第四下行数据为该终端设备未成功接收的数据，该第四下行数据为小数据；该第一网络设备向该终端设备发送该第四下行数据。
上述方案，第一网络设备支持在小数据包传输过程中避免数据丢失的机制，从第二网络设备接收终端设备未成功接收的数据，将该数据重传给终端设备，可以降低丢包率。
结合第一方面，在第一方面的某些实现方式中，该方法还包括：该第一网络设备向该第二网络设备发送第二请求消息，该第二请求消息用于请求获取该终端设备的上下文，该第二请求消息包括用于指示小数据包传输的指示信息；该第一网络设备接收来自该第二网络设备的第二响应消息，该第二响应消息包括用于指示执行锚点重定位的指示信息。
应理解，第一网络设备向第二网络设备请求终端设备的上下文，说明终端设备已经不在第二网络设备的覆盖范围内，第二网络设备执行锚点重定位，说明锚点gNB为第一网络设备。上述方案，通过锚点gNB为锚点重定位之前的锚点gNB向终端设备转发第四下行数据，可以减少由于终端设备不在第二网络设备的覆盖范围而导致丢包的情况，降低丢包率。
结合第一方面，在第一方面的某些实现方式中，该方法还包括：该第一网络设备向该第二网络设备发送第三请求消息，该第三请求消息用于请求获取该终端设备的上下文，该第三请求消息包括用于指示小数据包传输的指示信息；该第一网络设备接收来自该第二网络设备的第三响应消息，该第三响应消息包括用于指示不执行锚点重定位的指示信息。
应理解，第一网络设备向第二网络设备请求终端设备的上下文，说明终端设备已经不在第二网络设备的覆盖范围内，第二网络设备不执行锚点重定位，说明锚点gNB仍然为第二网络设备。上述方案，锚点gNB通过第一网络设备继续向终端设备转发第四下行数据，可以减少由于终端设备不在第二网络设备的覆盖范围而导致丢包的情况，降低丢包率。
结合第一方面，在第一方面的某些实现方式中，该方法还包括：该第一网络设备向该终端设备发送无线资源控制释放消息，该无线资源控制释放消息包括Y，Y为小数据包传输过程中小区重选的次数，Y为正整数。
第二方面，提供了一种数据传输的方法，该方法可以由第二网络设备执行，或者，也可以由第二网络设备的组成部件(例如芯片或者电路)执行，本申请对此不作限定。为了便于描述，下面以由第二网络设备执行为例进行说明。
该方法可以包括：第二网络设备向第一网络设备发送第一下行数据，该第一下行数据为小数据，该第一网络设备用于将该第一下行数据发送给终端设备；该第二网络设备接收来自该第一网络设备的第二反馈消息，该第二反馈消息用于指示终端设备成功接收或未成功接收该第一下行数据，该第二反馈消息与第二协议层对应；该第二网络设备根据第一发送窗口和该第二反馈消息确定第二发送窗口，该第一发送窗口包含该第一下行数据的序列号，在该第二反馈消息指示成功接收该第一下行数据的情况下，该第二发送窗口包含未向该终端设备发送的下行数据的序列号。
上述方案，第二网络设备通过第一网络设备将第一下行数据发送给终端设备，根据第一网络设备发送第二反馈消息确定终端设备是否成功接收第一下行数据，并且根据第二反馈消息调整发送窗口。在第二反馈消息指示终端设备成功接收第一下行数据的情况下，第二网络设备向前推动发送窗口。
结合第二方面，在第二方面的某些实现方式中，该第二反馈消息包括以下至少一项：该第一下行数据在该第二协议层的序列号、该第一下行数据在该第二协议层的超帧号、承载该第一下行数据的无线承载的标识、承载该第一下行数据的逻辑信道的标识。
结合第二方面，在第二方面的某些实现方式中，该方法还包括：该第二网络设备根据该第二反馈消息确定该第一发送窗口的前L个序列号对应的数据已经被该终端设备成功接收，该第二发送窗口的起始序列号等于第一发送窗口的第L+1个数据对应的序列号，L为正整数。
结合第二方面，在第二方面的某些实现方式中，该第二反馈消息用于指示该终端设备成功接收该第二协议层的序列号连续的N个数据，该N个数据包括该第一下行数据，N为正整数，L＝N。
上述方案，第一网络设备给第二网络设备反馈的N个数据的序列号是连续的，可以便于第二网络设备直接根据第二反馈消息将发送窗口往前推动N个序列号，也可以节省第二网络设备缓存数据的功耗。
结合第二方面，在第二方面的某些实现方式中，该第二协议层为分组数据汇聚层。
结合第二方面，在第二方面的某些实现方式中，该方法还包括：该第二网络设备接收来自该第一网络设备的第一请求消息，该第一请求消息用于请求获取该终端设备的上下文，该第一请求消息包括用于指示小数据包传输的指示信息；该第二网络设备向该第一网络设备发送第一响应消息，该第一响应消息包括用于指示不执行锚点重定位的指示信息。
应理解，第一网络设备向第二网络设备请求终端设备的上下文，说明终端设备已经不在第二网络设备的覆盖范围内，而第二网络设备不执行锚点重定向，说明第二网络设备仍然为锚点gNB。上述方案，在不执行锚点重定位的场景下，通过网络设备之间基于第二协议层的交互，使得锚点gNB获知终端设备的第一协议层的状态，便于锚点gNB根据终端设备的第一协议层的状态调整发送窗口，降低丢包率。
结合第二方面，在第二方面的某些实现方式中，包括：该第二网络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小数据包传输过程中避免数据丢失；该第二网络设备发送第四下行数据，该第四下行数据为小数据；该第二网络设备接收第一状态报告，该第一状态报告包括用于指示该终端设备未成功接收该第四下行数据的指示信息；该第二网络设备向第一网络设备发送该第四下行数据。
上述方案，第二网络设备支持在小数据包传输过程中避免数据丢失的机制，将终端设备未成功接收的数据发送给第二网络设备，通过第二网络设备向终端设备重传该数据，可以降低丢包率。
结合第二方面，在第二方面的某些实现方式中，该第二网络设备发送第四下行数据，包括：该第二网络设备向该终端设备发送该第四下行数据；该第二网络设备接收第一状态报告，包括：该第二网络设备接收来自该终端设备的该第一状态报告。
结合第二方面，在第二方面的某些实现方式中，该方法还包括：该第二网络设备接收来自该第一网络设备的第二请求消息，该第二请求消息用于请求获取该终端设备的上下文，该第二请求消息包括用于指示小数据包传输的指示信息；该第二网络设备向该第二网络设备发送第二响应消息，该第二响应消息包括用于指示执行锚点重定位的指示信息。
应理解，第一网络设备向第二网络设备请求终端设备的上下文，说明终端设备已经不在第二网络设备的覆盖范围内，第二网络设备执行锚点重定位，说明锚点gNB为第一网络设备。上述方案，通过锚点gNB为锚点重定位之前的锚点gNB向终端设备转发第四下行数据，可以减少由于终端设备不在第二网络设备的覆盖范围而导致丢包的情况，降低丢 包率。
结合第二方面，在第二方面的某些实现方式中，该第二网络设备发送第四下行数据，包括：该第二网络设备向第三网络设备发送该第四下行数据；该第二网络设备接收第一状态报告，包括：该第二网络设备接收来自该第三网络设备的该第一状态报告。
结合第二方面，在第二方面的某些实现方式中，该方法还包括：该第二网络设备向第三网络设备发送第四请求消息，该第四请求消息用于请求该第四下行数据的状态报告。
结合第二方面，在第二方面的某些实现方式中，该方法还包括：该第二网络设备接收来自该第一网络设备的第三请求消息，该第三请求消息用于请求获取该终端设备的上下文，该第三请求消息包括用于指示小数据包传输的指示信息；该第二网络设备向该第一网络设备发送第三响应消息，该第三响应消息包括用于指示不执行锚点重定位的指示信息。
应理解，第一网络设备向第二网络设备请求终端设备的上下文，说明终端设备已经不在第二网络设备的覆盖范围内，第二网络设备不执行锚点重定位，说明锚点gNB仍然为第二网络设备。上述方案，锚点gNB通过第一网络设备继续向终端设备转发第四下行数据，可以减少由于终端设备不在第二网络设备的覆盖范围而导致丢包的情况，降低丢包率。
结合第二方面，在第二方面的某些实现方式中，该方法还包括：该第一网络设备向该终端设备发送无线资源控制释放消息，该无线资源控制释放消息包括Y，Y为小数据包传输过程中小区重选的次数，Y为正整数。
第三方面，提供了一种数据传输的方法，该方法可以由终端设备执行，或者，也可以由终端设备的组成部件(例如芯片或者电路)执行，本申请对此不作限定。为了便于描述，下面以由终端设备执行为例进行说明。
该方法可以包括：终端设备接收来自第二网络设备的第二指示信息，该第二指示信息用于指示小数据包传输过程中避免数据丢失；该终端设备接收第四下行数据，该第四下行数据为小数据；该终端设备发送用于指示未成功接收该第四下行数据的指示信息；该终端设备接收来自第一网络设备的第一指示信息，该第一指示信息用于指示该第一网络设备支持在小数据包传输过程中避免数据丢失；该终端设备接收来自该第一网络设备的第四下行数据。
上述方案，终端设备根据第二指示信息确定第二网络设备支持小数据包传输过程中避免数据丢失的机制，根据第一指示信息确定第一网络设备支持小数据包传输过程中避免数据丢失的机制，终端设备从第一网络设备接收到了从第二网络设备未成功接收第四下行数据，可以降低小数据包传输过程中的丢包率。
结合第三方面，在第三方面的某些实现方式中，该终端设备接收第四下行数据，包括：该终端设备接收来自该第二网络设备的该第四下行数据；该终端设备发送用于指示未成功接收该第四下行数据的指示信息，包括：该终端设备向该第二网络设备发送第一状态报告，该第一状态报告包括该指示信息。
结合第三方面，在第三方面的某些实现方式中，该终端设备接收第四下行数据，包括：该终端设备接收来自该第三网络设备的该第四下行数据；该终端设备发送用于指示未成功接收该第四下行数据的指示信息，包括：该终端设备向第三网络设备发送第二状态报告，该第二状态报告包括该指示信息。
结合第三方面，在第三方面的某些实现方式中，该方法还包括：该终端设备接收来自 该网络设备的无线资源控制释放消息，该无线资源控制释放消息包括Y，Y为小数据包传输过程中小区重选的次数，Y为正整数；该终端设备发起小数据包传输过程；该终端设备记录小区重选的次数；在该终端设备记录的小区重选的次数≥Y的情况下，该终端设备切换至无线资源控制空闲态，或者，该终端设备向网络设备发送非小数据包传输的恢复请求消息。
第四方面，提供了一种数据传输的方法，该方法可以由第三网络设备执行，或者，也可以由第三网络设备的组成部件(例如芯片或者电路)执行，本申请对此不作限定。为了便于描述，下面以由第三网络设备执行为例进行说明。
该方法可以包括：第三网络设备接收来自第二网络设备的第四下行数据，该第四下行数据为小数据；该第三网络设备向终端设备发送该第四下行数据；该第三网络设备接收来自该终端设备的第二状态报告，该第二状态报告包括用于指示该终端设备未成功接收该第四下行数据的指示信息；该第三网络设备根据该第二状态报告向该第二网络设备发送第一状态报告，该第一状态报告包括用于指示该终端设备未成功接收该第四下行数据的指示信息。
结合第四方面，在第四方面的某些实现方式中，该方法还包括：该第三网络设备接收来自该第二网络设备的第四请求消息，该第四请求消息用于请求该第四下行数据的状态报告。
结合第四方面，在第四方面的某些实现方式中，该方法还包括：该第三网络设备释放与该终端设备的链路，停止与该终端设备通信。
第五方面，提供了一种数据传输的方法，该方法可以由第一网络设备执行，或者，也可以由第一网络设备的组成部件(例如芯片或者电路)执行，本申请对此不作限定。为了便于描述，下面以由第一网络设备执行为例进行说明。
该方法可以包括：第一网络设备向终端设备发送第一指示信息，该第一指示信息用于指示该第一网络设备支持在小数据包传输过程中避免数据丢失；该第一网络设备接收来自第二网络设备的第四下行数据，该第四下行数据为该终端设备未成功接收的数据，该第四下行数据为小数据；该第一网络设备向该终端设备发送该第四下行数据。
结合第五方面，在第五方面的某些实现方式中，该方法还包括：该第一网络设备向该第二网络设备发送第二请求消息，该第二请求消息用于请求获取该终端设备的上下文，该第二请求消息包括用于指示小数据包传输的指示信息；该第一网络设备接收来自该第二网络设备的第二响应消息，该第二响应消息包括用于指示执行锚点重定位的指示信息。
结合第五方面，在第五方面的某些实现方式中，该方法还包括：该第一网络设备向该第二网络设备发送第三请求消息，该第三请求消息用于请求获取该终端设备的上下文，该第三请求消息包括用于指示小数据包传输的指示信息；该第一网络设备接收来自该第二网络设备的第三响应消息，该第三响应消息包括用于指示不执行锚点重定位的指示信息。
结合第五方面，在第五方面的某些实现方式中，该方法还包括：该第一网络设备向该终端设备发送无线资源控制释放消息，该无线资源控制释放消息包括Y，Y为小数据包传输过程中小区重选的次数，Y为正整数。
第六方面，提供了一种数据传输的方法，该方法可以由第二网络设备执行，或者，也可以由第二网络设备的组成部件(例如芯片或者电路)执行，本申请对此不作限定。为了 便于描述，下面以由第二网络设备执行为例进行说明。
该方法可以包括：第二网络设备向终端设备发送第二指示信息，该第二指示信息用于指示小数据包传输过程中避免数据丢失；该第二网络设备发送第四下行数据，该第四下行数据为小数据；该第二网络设备接收第一状态报告，该第一状态报告包括用于指示该终端设备未成功接收该第四下行数据的指示信息；该第二网络设备向第一网络设备发送该第四下行数据。
结合第六方面，在第六方面的某些实现方式中，该第二网络设备发送第四下行数据，包括：该第二网络设备向该终端设备发送该第四下行数据；该第二网络设备接收第一状态报告，包括：该第二网络设备接收来自该终端设备的该第一状态报告。
结合第六方面，在第六方面的某些实现方式中，该方法还包括：该第二网络设备接收来自该第一网络设备的第二请求消息，该第二请求消息用于请求获取该终端设备的上下文，该第二请求消息包括用于指示小数据包传输的指示信息；该第二网络设备向该第二网络设备发送第二响应消息，该第二响应消息包括用于指示执行锚点重定位的指示信息。
结合第六方面，在第六方面的某些实现方式中，该第二网络设备发送第四下行数据，包括：该第二网络设备向第三网络设备发送该第四下行数据；该第二网络设备接收第一状态报告，包括：该第二网络设备接收来自该第三网络设备的该第一状态报告。
结合第六方面，在第六方面的某些实现方式中，该方法还包括：该第二网络设备向第三网络设备发送第四请求消息，该第四请求消息用于请求该第四下行数据的状态报告。
结合第六方面，在第六方面的某些实现方式中，该方法还包括：该第二网络设备接收来自该第一网络设备的第三请求消息，该第三请求消息用于请求获取该终端设备的上下文，该第三请求消息包括用于指示小数据包传输的指示信息；该第二网络设备向该第一网络设备发送第三响应消息，该第三响应消息包括用于指示不执行锚点重定位的指示信息。
第七方面，提供了一种数据传输的方法，该方法可以由第一网络设备执行，或者，也可以由第一网络设备的组成部件(例如芯片或者电路)执行，本申请对此不作限定。为了便于描述，下面以由第一网络设备执行为例进行说明。
该方法可以包括：第一网络设备向终端设备发送第一指示信息，该第一指示信息用于指示该第一网络设备支持在小数据包传输过程中避免数据丢失；该第一网络设备接收来自第二网络设备的第四下行数据，该第四下行数据为该终端设备未成功接收的数据，该第四下行数据为小数据；该第一网络设备向该终端设备发送该第四下行数据。
结合第七方面，在第七方面的某些实现方式中，该方法还包括：该第一网络设备向该第二网络设备发送第二请求消息，该第二请求消息用于请求获取该终端设备的上下文，该第二请求消息包括用于指示小数据包传输的指示信息；该第一网络设备接收来自该第二网络设备的第二响应消息，该第二响应消息包括用于指示执行锚点重定位的指示信息。
结合第七方面，在第七方面的某些实现方式中，该方法还包括：该第一网络设备向该第二网络设备发送第三请求消息，该第三请求消息用于请求获取该终端设备的上下文，该第三请求消息包括用于指示小数据包传输的指示信息；该第一网络设备接收来自该第二网络设备的第三响应消息，该第三响应消息包括用于指示不执行锚点重定位的指示信息。
结合第七方面，在第七方面的某些实现方式中，该方法还包括：该第一网络设备向该终端设备发送无线资源控制释放消息，该无线资源控制释放消息包括Y，Y为小数据包传 输过程中小区重选的次数，Y为正整数。
第八方面，提供了一种数据传输的方法，该方法可以由第二网络设备执行，或者，也可以由第二网络设备的组成部件(例如芯片或者电路)执行，本申请对此不作限定。为了便于描述，下面以由第二网络设备执行为例进行说明。
该方法可以包括：第二网络设备向终端设备发送第二指示信息，该第二指示信息用于指示小数据包传输过程中避免数据丢失；该第二网络设备发送第四下行数据，该第四下行数据为小数据；该第二网络设备接收第一状态报告，该第一状态报告包括用于指示该终端设备未成功接收该第四下行数据的指示信息；该第二网络设备向第一网络设备发送该第四下行数据。
结合第八方面，在第八方面的某些实现方式中，该第二网络设备发送第四下行数据，包括：该第二网络设备向该终端设备发送该第四下行数据；该第二网络设备接收第一状态报告，包括：该第二网络设备接收来自该终端设备的该第一状态报告。
结合第八方面，在第八方面的某些实现方式中，该方法还包括：该第二网络设备接收来自该第一网络设备的第二请求消息，该第二请求消息用于请求获取该终端设备的上下文，该第二请求消息包括用于指示小数据包传输的指示信息；该第二网络设备向该第二网络设备发送第二响应消息，该第二响应消息包括用于指示执行锚点重定位的指示信息。
结合第八方面，在第八方面的某些实现方式中，该第二网络设备发送第四下行数据，包括：该第二网络设备向第三网络设备发送该第四下行数据；该第二网络设备接收第一状态报告，包括：该第二网络设备接收来自该第三网络设备的该第一状态报告。
结合第八方面，在第八方面的某些实现方式中，该方法还包括：该第二网络设备向第三网络设备发送第四请求消息，该第四请求消息用于请求该第四下行数据的状态报告。
结合第八方面，在第八方面的某些实现方式中，该方法还包括：该第二网络设备接收来自该第一网络设备的第三请求消息，该第三请求消息用于请求获取该终端设备的上下文，该第三请求消息包括用于指示小数据包传输的指示信息；该第二网络设备向该第一网络设备发送第三响应消息，该第三响应消息包括用于指示不执行锚点重定位的指示信息。
结合第八方面，在第八方面的某些实现方式中，该方法还包括：该第一网络设备向该终端设备发送无线资源控制释放消息，该无线资源控制释放消息包括Y，Y为小数据包传输过程中小区重选的次数，Y为正整数。
络设备向该终端设备发送无线资源控制释放消息，该无线资源控制释放消息包括Y，Y为小数据包传输过程中小区重选的次数，Y为正整数。
第九方面，提供了一种数据传输的方法，该方法可以由第一网络设备执行，或者，也可以由第一网络设备的组成部件(例如芯片或者电路)执行，本申请对此不作限定。为了便于描述，下面以由第一网络设备执行为例进行说明。
该方法可以包括：第一网络设备向终端设备发送第一指示信息，该第一指示信息用于指示该第一网络设备支持在小数据包传输过程中避免数据丢失；该第一网络设备接收来自第二网络设备的第一上行数据，该第一上行数据是该第二网络设备成功接收的数据，该第一上行数据为小数据；该第一网络设备接收来自该终端设备的第二上行数据，该第二上行数据是该第二网络设备未成功接收的来自该终端设备的数据，该第二上行数据为小数据。
结合第九方面，在第九方面的某些实现方式中，该方法还包括：该第一网络设备向该 第二网络设备发送第二请求消息，该第二请求消息用于请求获取该终端设备的上下文，该第二请求消息包括用于指示小数据包传输的指示信息；该第一网络设备接收来自该第二网络设备的第二响应消息，该第二响应消息用于指示第二网络设备决定执行锚点重定位。
第十方面，提供了一种数据传输的方法，该方法可以由第二网络设备执行，或者，也可以由第二网络设备的组成部件(例如芯片或者电路)执行，本申请对此不作限定。为了便于描述，下面以由第二网络设备执行为例进行说明。
该方法可以包括：第二网络设备向终端设备发送第二指示信息，该第二指示信息用于指示小数据包传输过程中避免数据丢失；该第二网络设备接收来自该终端设备的第四上行数据，该第四上行数据为小数据；该第二网络设备向该终端设备发送第三状态报告，该第三状态报告包括以下指示信息中的至少一项：用于指示成功接收第一上行数据的指示信息，用于指示未成功接收第二上行数据的指示信息，该第四上行数据包括该第一上行数据和该第二上行数据；该第二网络设备向第一网络设备发送该第一上行数据。
结合第十方面，在第十方面的某些实现方式中，该方法还包括：该第二网络设备接收来自该第二网络设备的第二请求消息，该第二请求消息用于请求获取该终端设备的上下文，该第二请求消息包括用于指示小数据包传输的指示信息；该第二网络设备向该第二网络设备发送第二响应消息，该第二响应消息用于指示第二网络设备决定执行锚点重定位。
第十一方面，提供了一种数据传输的方法，该方法可以由终端设备执行，或者，也可以由终端设备的组成部件(例如芯片或者电路)执行，本申请对此不作限定。为了便于描述，下面以由终端设备执行为例进行说明。
该方法可以包括：终端设备接收来自第二网络设备的第二指示信息，该第二指示信息用于指示小数据包传输过程中避免数据丢失；该终端设备向该第二网络设备发送第四上行数据，该第四上行数据为小数据；该终端设备接收来自该第二网络设备的第三状态报告，该第三状态报告包括以下指示信息中的至少一项：用于指示成功接收第一上行数据的指示信息，用于指示未成功接收第二上行数据的指示信息，其中，该第四上行数据包括该第一上行数据和该第二上行数据；该终端设备接收来自第一网络设备的第一指示信息，该第一指示信息用于指示该第一网络设备支持在小数据包传输过程中避免数据丢失；该终端设备向该第一网络设备发送该第二上行数据。
第十二方面，提供了一种数据传输的方法，该方法可以由终端设备执行，或者，也可以由终端设备的组成部件(例如芯片或者电路)执行，本申请对此不作限定。为了便于描述，下面以由终端设备执行为例进行说明。
该方法可以包括：终端设备接收来自网络设备的无线资源控制释放消息，该无线资源控制释放消息包括Y，Y为小数据包传输过程中小区重选的次数，Y为正整数；该终端设备发起小数据包传输过程；该终端设备记录小区重选的次数；在该终端设备记录的小区重选的次数≥Y的情况下，该终端设备切换至无线资源控制空闲态，或者，该终端设备向网络设备发送非小数据包传输的恢复请求消息。
上述方案，通过为终端设备小区重选的次数设置阈值，并由终端设备统计小区重选次数，当小区重选的次数达到阈值时，停止小区重选或者切换到空闲态或者发起非小数据包传输恢复过程，减少持续的小数据包传输失败而导致的通信效率降低的情况，提高通信效率。
第十三方面，提供一种数据传输的装置，该装置用于执行上述第一方面至第十二方面任一种可能实现方式中的方法。具体地，该装置可以包括用于执行第一方面至第十二方面任一种可能实现方式中的方法的单元和/或模块，如处理单元和/或通信单元。
在一种实现方式中，该装置为通信设备(如网络设备，又如终端设备)。当该装置为通信设备时，通信单元可以是收发器，或，输入/输出接口；处理单元可以是至少一个处理器。可选地，收发器可以为收发电路。可选地，输入/输出接口可以为输入/输出电路。
在另一种实现方式中，该装置为用于通信设备(如网络设备，又如终端设备)的芯片、芯片系统或电路。当该装置为用于通信设备的芯片、芯片系统或电路时，通信单元可以是该芯片、芯片系统或电路上的输入/输出接口、接口电路、输出电路、输入电路、管脚或相关电路等；处理单元可以是至少一个处理器、处理电路或逻辑电路等。
第十四方面，提供一种数据传输的装置，该装置包括：至少一个处理器，用于执行存储器存储的计算机程序或指令，以执行上述第一方面至第十二方面任一种可能实现方式中的方法。可选地，该装置还包括存储器，用于存储的计算机程序或指令。可选地，该装置还包括通信接口，处理器通过通信接口读取存储器存储的计算机程序或指令。
在一种实现方式中，该装置为通信设备(如网络设备，又如终端设备)。
在另一种实现方式中，该装置为用于通信设备(如网络设备，又如终端设备)的芯片、芯片系统或电路。
第十五方面，本申请提供一种处理器，用于执行上述第一方面至第十二方面提供的方法。
对于处理器所涉及的发送和获取/接收等操作，如果没有特殊说明，或者，如果未与其在相关描述中的实际作用或者内在逻辑相抵触，则可以理解为处理器输出和接收、输入等操作，也可以理解为由射频电路和天线所进行的发送和接收操作，本申请对此不做限定。
第十六方面，提供一种计算机可读存储介质，该计算机可读介质存储用于设备执行的程序代码，该程序代码包括用于执行上述第一方面至第十二方面任一种可能实现方式中的方法。
第十七方面，提供一种包含指令的计算机程序产品，当该计算机程序产品在计算机上运行时，使得计算机执行上述第一方面至第十二方面任一种可能实现方式中的方法。
第十八方面，提供一种通信系统，包括前述的第一网络设备和第二网络设备。
附图说明
图1示出了应用本申请实施例的一种通信系统的示意性图。
图2示出了UE和gNB之间通过协议栈进行数据传输的示意图。
图3中的(a)示出了上一个服务的gNB决定不执行锚点重定位的场景下的协议栈分布，图3中的(b)示出了上一个服务的gNB决定执行锚点重定位的场景下的协议栈分布。
图4示出了本申请提供的数据传输的方法100的示意图。
图5示出了本申请提供的数据传输的方法110的示意图。
图6示出了本申请提供的数据传输的方法120的示意图。
图7示出了本申请提供的数据传输的方法200的示意图。
图8示出了本申请提供的数据传输的方法300的示意图。
图9出了本申请提供的数据传输的方法400的示意图。
图10示出了本申请提供的数据传输的方法500的示意性流程图。
图11示出了本申请提供的数据传输的方法500的示意性框图。
图12是本申请实施例提供的一种数据传输的装置600的示意图。
图13是本申请实施例提供的另一种数据传输的装置700的示意图。
图14是本申请实施例提供的芯片系统800的示意图。
具体实施方式
为了使本申请的目的、技术方案和优点更加清楚，下面将结合附图对本申请作进一步地详细描述。方法实施例中的具体操作方法也可以应用于装置实施例或系统实施例中。
本申请提供的通信方法可以应用于各类通信系统中，例如，可以是物联网(internet of things，IoT)、窄带物联网(narrow band internet of things，NB-IoT)、长期演进(long term evolution，LTE)，也可以是第五代(5thgeneration，5G)通信系统，还可以是LTE与5G混合架构、也可以是5G新无线(new radio，NR)系统以及6G或者未来通信发展中出现的新的通信系统等。本申请所述的通信系统还可以是机器到机器(machine to machine，M2M)网络或者其他网络。
图1示出了应用本申请实施例的一种通信系统的示意性图。在5G系统中，5G接入点由基站节点下一代无线接入网(next generation radio access network，NG-RAN)构成，NG-RAN节点可能是一个5G新基站节点(generation nodeb，gNB)，也可能是一个LTE演进基站节点(next generation enodeb，ng-eNB)。其中，gNB使用NR的用户面和控制面协议栈，而ng-eNB除服务数据适应协议(Service Data Adaptation Protocol,SDAP)层外使用演进的通用陆地无线接入(evolved universal terrestrial radio access，E-UTRA)的用户面和控制面协议栈。
gNB和gNB、ng-eNB和ng-eNB、gNB和ng-eNB之间通过Xn接口互连。gNB和ng-eNB通过NG接口连接到5G核心网，其中控制面通过NG-C接口连接到接入网和移动性管理模块(access and mobility management function，AMF)，通过用户面NG-U接口连接到用户面功能(user plane function，UPF)模块。
为了便于理解本申请实施例，下面介绍本申请涉及的一些技术用语。
一、无线资源控制(radio resource control，RRC)状态
RRC状态包括：无线资源控制连接态(RRC connected)、无线资源控制空闲态(RRCidle)或无线资源控制非激活态(RRCinactive)。
在RRCconnected下，终端设备与接入网设备之间有专用的RRC连接。这个专用的RRC连接是数据无线承载(data radio bearer，DRB)或信令无线承载1(signal Radio Bearer 1，SRB1)的连接。在RRCidle下，终端设备与接入网设备没有专用的RRC连接。
在RRCinactive下，终端设备在基于RAN的通知区域(RAN based notification area，RNA)下移动，可以不知会接入网设备。终端设备保存自己的上下文，上一个服务的gNB(last serving gNB)保存终端设备的上下文，以及与AMF和UPF的NG连接。终端设备与接入网设备的专用的RRC连接是挂起的，后续可以恢复的。终端设备可以在RRC inactive执行小区重选。
其中，RRC inactive可以使用户设备(user equipment，UE)快速恢复到RRCconnected，而无需重新接入。RRC inactive和RRCidle类似，都只能接收公共搜索空间的内容(如paging、广播)，可以进行小区重选。RRC inactive可以获得与RRC空闲态相近的功耗水平，原因是在RRC inactive的UE会暂停数据处理。若UE在同一个RNA中移动时，则不需要与gNB交互信息。但若UE移出RNA范围时，则需要启动RNA更新过程。处于RRC inactive的UE可以有较低的数传恢复时延，原因是RRC inactive的UE可以通过RRC恢复(resume)流程快速迁移到RRC连接态。
二、连接管理(connection management，CM)状态
CM状态由UE和AMF间的非接入层(non-access stratum，NAS)信令连接的建立和释放两部分组成。NAS信令连接用于UE和核心网之间进行NAS信令交互。其包含两部分连接：1)UE和接入网络(accessnetwork，AN)之间的信令连接，如第三代合作伙伴计划(3rd generation partnership project，3GPP)接入模式下的RRC连接、非3GPP互通功能(non-3GPP interworking function，N3IWF)，2)AN和AMF之间的N2连接。
三、小数据包传输(small data transmission，SDT)技术
在SDT出现之前，如果处于非激活态的终端设备需要传输数据包，需先触发RRC连接恢复过程切换到连接态。SDT技术使得终端设备能够处在非激活态传输短数据包，避免了频繁触发RRC连接恢复过程带来的信令开销和能源消耗。
SDT的场景可以有多种，具体可以涵盖智能手机相关业务，比如应用程序(application，APP)的心跳包或推送消息；以及非智能手机的相关业务，比如可穿戴设备的周期性数据(例如心跳包)、工业无线传感器网络所发送的周期性数据等等。此外，本申请实施例中对小数据的具体大小可以不做限定，比如100～300字节的数据包可以认为是小数据。
可以理解的是，本申请实施例下文中所描述的数据传输、小数据包传输可以是指SDT，本申请实施例所描述的上行数据、下行数据和数据包均可以为小数据。
四、协议栈
在5G系统中，协议栈包括以下协议层：业务数据适配协议(service data adaptation protocol，SDAP)，分组数据汇聚层协议(packet data convergence protocol，PDCP)，无线链路控制(radio link control，RLC)，媒体接入控制(medium access control，MAC)，物理(physical，PHY)，不同的协议层有个各自的功能。
图2示出了UE和gNB之间通过协议栈进行数据传输的示意图。UE为发送方时，gNB为接收方，UE为接收方时，gNB为发送方。其中，发送方数据处理的顺序：SDAP->PDCP->RLC->MAC->PHY。SDAP在接受到数据之后，主要的处理包括：服务质量(quality of service，QoS)流(flow)到无线承载(radio bearer，RB)的映射，处理完的数据递交给PDCP。数据在PDCP的主要的处理包括：加密，完整性保护，头压缩，添加PDCP序列号(serial number，SN)等。在PDCP层得到不同RB的数据，终端对不同的RB做各自的处理。一个逻辑信道对应一个RB，递交处理后的数据给RLC。数据在RLC的主要处理：对于确认模式(acknowledge mode，AM)，自动重传请求(automatic repeat-request，ARQ)，分段，重组，添加RLCSN，对于非确认模式(unacknowledged mode，UM)，分段，重组，添加RLCSN。数据在MAC的处理，主要包括逻辑信道的复用，混合自动重传请求(hybrid automatic repeat-request，HARQ)。一个数据包按照以上的顺序 进行处理，最终由PHY发送出去。在接收方，从采取相反的顺序进行逆向处理。
五、窗口推动定时器
下面以PDCP发送窗口的窗口推动定时器为了进行介绍。如果接收方的RLC确定接收到一个数据包，会通过内部实现的方式通知接收方的PDCP，以便PDCP进行PDCP的接收窗口维护。如果一个数据包的RLC反馈(feedback)是确认(acknowledgement，ACK)，那么PDCP的接收窗口就可以往前推动，否则，窗口维持不动，等待发送方重传该数据包，启动窗口推动定时器。当窗口推动定时器超时，此时无论数据包是否重传，或者重传的数据包是否被成功接收，接收方的PDCP都会推动PDCP的接收窗口，避免PDCP的接收窗口卡死在某个位置。接收方向发送方指示RLC状态，发送方根据接收方的指示维护PDCP发送窗口，维护方式与接收方类似。例如，PDCP的当前发送窗口是[0,99]，也就是说，PDCP等待发送的是PDCP SN从0到99号的包。一种实现方式，假设RLC指示PDCP SN为0和1的包成功接收，那么PDCP的发送窗口可以向前推动到[2,101]。另一种实现方式，如果窗口推动定时器超时，那么发送窗口也可以推动到[2,101]。并且，在窗口推动到[2,101]，发送方就不再重新发送PDCP SN为0、1的数据包了。
六、锚点gNB需要决定是否执行锚点重定位的场景
UE通过一个gNB与网络通信，该gNB为UE配置一个标识，例如无线网络临时标识，该gNB还为UE配置一个RNA。UE在该RNA内移动时，如果需要传输少量数据，可以与网络进行小数据包传输。那么就需要通过小数据包传输的随机接入过程与该RNA范围内的其他gNB建立连接。例如，本申请将为UE配置RNA的gNB称为上一个服务的gNB，将该RNA范围内的其他gNB称为接收gNB(receiving gNB)。并且，接收gNB只要从UE接收到该标识，就可以根据该标识确定要向上一个服务的gNB请求UE的上下文。
具体地，在小数据包传输的随机接入过程中，终端设备(user equipment，UE)移动后不在上一个服务的gNB覆盖范围内时，可以通过接收gNB接入网络。UE向接收gNB发送RRC恢复请求消息(RRC resume request)。该RRC恢复请求消息中携带该标识，该标识是由上一个服务的gNB分配的。接收gNB接收到RRC恢复请求消息后，根据该标识向上一个服务的gNB(last serving gNB)发送获取UE上下文请求消息(retrieve UE context request)。上一个服务的gNB接收到获取UE上下文请求消息后决定是否要执行锚点重定位。例如，上一个服务的gNB可以根据自身负载决定是否要执行锚点重定位，或者，可以根据接收gNB提供的信息决定是否要执行锚点重定位。
可选地，终端设备向接收gNB发起小数据包传输过程之前，或者说，终端设备向接收gNB发送RRC恢复请求消息之前，还可以进行小区重选，重选到接收gNB所在的小区。
七、不执行锚点重定位的场景下的协议栈分布
在上一个服务的gNB决定不执行锚点重定位(without anchor relocation)的场景下，协议栈分布如图3中的(a)所示。其中，箭头表示第一数据的传输路径，第一数据可以是用户数据或非接入层(non-access stratum，NAS)消息。UE向接收的gNB发送第一数据，随后接收gNB通过Xn接口将第一数据发送给上一个服务的gNB。上一个服务的gNB为锚点gNB。UE按照SDAP->PDCP->RLC->MAC->PHY将第一数据发送出去，接收gNB按照PHY->MAC->RLC的顺序接收第一数据后，通过Xn接口基于RLC业务数据单元向 上一个服务的gNB发送第一数据。
八、不执行锚点重定位场景下的协议栈分布
在上一个服务的gNB决定执行锚点重定位(with anchor relocation)的场景下，协议栈分布如图3中的(b)所示。其中，箭头表示用户数据或非接入层(non-access stratum，NAS)消息的传输路径。UE按照SDAP->PDCP->RLC->MAC->PHY将第一数据发送出去，接收gNB按照PHY->MAC->RLC->PDCP->SDAP的顺序接收第一数据。其中，锚点gNB为接收gNB。
目前，在上述SDT过程中，可能出现丢包的问题，因此，如何降低丢包率称为亟待解决的问题。需要说明的是，在本申请实施例中，在不执行锚点重定位的场景下(例如方法200和方法500)，锚点gNB为上一个服务的gNB，例如，UE可以通过接受gNB与锚点gNB通信；在执行锚点重定位的场景下(例如方法300和方法400)，锚点gNB为接收gNB，例如，UE可以与锚点gNB直接通信。
下面结合图4至图11介绍本申请提供的数据传输的方法。下面先结合图4、5和6分别介绍方法100、110、和120。方法100、110、和120中的至少两个方法都可以结合，且本申请不限制执行顺序。方法100、110、和120中的至少一个也可以和方法600结合。
图4示出了本申请提供的数据传输的方法100的示意图。
S101，第二网络设备向第一网络设备发送第一下行数据，相应地，第一网络设备接收来自第二网络设备的第一下行数据，第一下行数据为小数据。
示例性地，第一网络设备和第二网络设备可以是同一个RNA中的两个gNB，第二网络设备保存着终端设备的上下文。例如，第一网络设备可以是接收gNB，第二网络设备可以是上一个服务的gNB。再例如，终端设备、第一网络设备和第二网络设备的协议栈分布可以参见图3中的(a)。
示例性地，第二网络设备基于分组数据汇聚层向第二网络设备发送第一下行数据。
可选地，S101之前，第一网络设备向第二网络设备发送第一请求消息，第一请求消息用于请求获取终端设备的上下文，第一请求消息包括用于指示小数据包传输的指示信息；第一网络设备接收来自第二网络设备的第一响应消息，第一响应消息包括用于指示不执行锚点重定位的指示信息。可以理解的是，第二网络设备仍然为锚点gNB，协议栈中的RLC、MAC、PHY迁移至第一网络设备，PDCP和SDAP还在第二网络设备，例如图3中的(a)所示。另外，第二响应消息包括SDT上下文，关于SDT上下文的介绍可以参见方法200的S204。
S102，第一网络设备向终端设备发送第一下行数据，相应地，终端设备接收来自第一网络设备的第一下行数据。
示例性地，第一网络设备基于无线链路控制层向终端设备发送第一下行数据。
S103，终端设备向第一网络设备发送第一反馈消息，相应地，第一网络设备接收来自终端设备的第一反馈消息，第一反馈消息用于指示成功或未成功接收第一下行数据，所述一反馈消息对应第一协议层。
示例性地，第一协议层为无线链路控制层。
示例性地，第一反馈消息包括以下至少一项：第一下行数据在无线链路控制层的序列号、承载第一下行数据的无线承载的标识、承载第一下行数据的逻辑信道的标识。
S104，第一网络设备根据第一反馈消息向第二网络设备发送第二反馈消息，相应地，第二网络设备接收来自第一网络设备的第二反馈消息，所述第二反馈消息对应第二协议层。第一反馈消息用于指示成功接收第一下行数据的情况下，第二反馈消息用于指示终端设备成功接收第一下行数据。或者，第一反馈消息用于指示未成功接收第一下行数据的情况下，第二反馈消息用于指示终端设备未成功接收第一下行数据。
示例性地，第二协议层为分组数据汇聚层。
示例性地，第二反馈消息包括以下至少一项：第一下行数据在分组数据汇聚层的序列号、第一下行数据在无线链路控制层的序列号、承载第一下行数据的无线承载的标识、承载第一下行数据的逻辑信道的标识。
关于何时执行S104，可以有两种不同的实现方式。
实现方式一，第一网络设备设置一个定时器，该定时器超时时执行S104。
该定时器的启动时间可以是第一网络设备接收到一个下行数据对应的反馈消息的时间。这里的反馈消息用于指示成功或未成功接收该一个下行数据，该一个下行数据可以是第一下行数据，也可以是除第一下行数据以外的下行数据。示例性地，该定时器的定时时长可以是预配置的，或者是由第一网络设备或第二网络设备确定的。
具体示例可以参见S212中的实现方式一。
实现方式二，第一网络设备根据第一反馈消息确定终端设备成功接收无线链路控制层的数据中包括序列号连续的至少N个数据，该N个数据包括第一下行数据，执行S104。换句话说，第一网络设备每确定有N个数据的序列号连续，就可以向第二网络设备指示成功接收N个数据，而且该N个数据包括该第一下行数据。
示例性地，步骤1，所述第一网络设备根据第一反馈消息确定终端设备成功接收第一协议层的M个数据，M为正整数，所述M个数据包括第一下行数据。
应理解，这M个数据中不包括第一网络设备已经向第二网络设备指示过的、终端设备已经成功接收的数据，换句话说，第一网络设备还未向第二网络设备指示成功接收M个数据。示例性地，第一网络设备除了接收第一反馈消息，还可能接收到反馈消息A，反馈消息A用于指示成功接收下行数据A，下行数据A是除了第一下行数据以外的下行数据。M个数据包括第一下行数据和下行数据A。
步骤2，当所述M个数据中，序列号连续的数据的个数大于或等于N时，所述第一网络设备向所述第二网络设备发送第二反馈消息，所述第二反馈消息用于指示所述终端设备成功接收所述第二协议层的N个数据，所述N个数据包括所述第一下行数据，所述N为正整数。
应理解，将M个数据按照每个数据对应的第二协议层的序列号进行排序，当M个数据中存在N个数据的序列号连续时，第一网络设备就可以向第二网络设备发送第二反馈消息。
示例性地，第二反馈消息中指示的N个数据为，该M个数据的分组数据汇聚层的序列号从小到大依次排列后的前N个数据。
具体示例可以参见S212中的实现方式二。
S105，第二网络设备根据第一发送窗口和第二反馈消息确定第二发送窗口，第一发送窗口包含第一下行数据的序列号，在第二反馈消息指示成功接收第一下行数据的情况下， 第二发送窗口包含未向终端设备发送的下行数据的序列号。
示例性地，在第二反馈消息指示未成功接收第一下行数据的情况下，第二网络设备可以不调整第一发送窗口，换句话说，第一发送窗口和第二发送窗口一致。
示例性地，在第二反馈消息指示成功接收第一下行数据的情况下，第二网络设备根据第二反馈消息确定第一发送窗口的前L个序列号对应的数据已经被终端设备成功接收，L为正整数，那么确定出的第二发送窗口的起始序列号等于第一发送窗口的第L+1个数据对应的序列号，
可选地，与S104中的实现方式二对应，L也可以等于N。
具体示例可以参见S213中的描述。
示例性地，方法200可以理解为方法100的一种可能的实现方式。
上述方案，在小数据包传输过程中，通过第一网络设备向第二网络设备(锚点gNB)发送第二反馈消息，该第二反馈消息指示终端设备成功或未成功接收第一下行数据，第二网络设备可以根据该反馈消息决定如何调整PDCP发送窗口，本申请实施例通过网络设备之间的交互，使得锚点gNB获取终端设备的RLC状态，从而可以根据终端设备成功接收的数据推动PDCP发送窗口，降低丢包率。
图5示出了本申请提供的数据传输的方法110的示意图。
S111，第二网络设备向终端设备发送第二指示信息，相应地，终端设备接收来自第二网络设备的第二指示信息，所述第二指示信息用于指示小数据包传输过程中允许/使能避免数据丢失。
示例性地，第二指示信息可以承载于RRC释放消息中，或者，也可以承载在其他消息中，本申请对此不做限定。在RRC释放消息中，携带一个显示的指示信息，可以指示终端设备进入RRC非激活态。
该第二指示信息还可以理解为用于向终端设备指示后续进行的SDT过程中，如果发生SDT失败，例如小区重选，第二网络设备支持避免上行数据的丢失的机制，具体地，该机制包括方法110中的后续步骤。示例性地，这里的第二指示信息可以表示为a flag to enable avoidance of data loss，或者，还可以是具备类似的功能的其他表示方式，本申请不做限制。
S112、S113和S114可以有多种实现方式，例如方案1中，S112-a，S113为S113-a，S114为S114-a，或者，方案2中，S112为S112-b-1和S112-b-2，S113为S113-b-1和S113-b-2，S114为S114-b。
例如，方案1中，第二网络设备直接向终端设备发送第四下行数据，相应地，终端设备直接接收来自第二网络设备的第四下行数据。终端设备直接向第二网络设备反馈第四下行数据对应的状态报告，相应地，第二网络设备直接接收来自终端设备的第四下行数据对应的状态报告。且第一网络设备是锚点gNB。方案2中，第二网络设备间接(通过其他设备)向终端设备发送第四下行数据，相应地，终端设备间接(通过其他设备)接收来自第二网络设备的第四下行数据。终端设备间接(通过其他设备)向第二网络设备反馈第四下行数据对应的状态报告，相应地，第二网络设备间接(通过其他设备)接收来自终端设备的第四下行数据对应的状态报告。第一网络设备不是锚点gNB。
可以理解的是，方案2中，第二网络设备可以通过第三网络设备将第四下行数据发送 给终端设备，终端设备也可以先向第三网络设备反馈第二状态报告，第三网络设备再根据第二状态报告向第二网络设备发送第一状态报告。一种可能的实现方式，第三网络设备和第二网络设备可以是同一个RNA中的两个gNB，第二网络设备保存着终端设备的上下文。例如，第三网络设备可以是接收gNB，第二网络设备可以是上一个服务的gNB。一种可能的实现方式，可以参见500中对应的描述。需要说明的是，方案2的后续步骤中，涉及终端设备进行小区重选，重选至第一网络设备的小区，那么第一网络设备可以是接收gNB，第二网络设备可以是上一个服务的gNB。为了区分第三网络设备和第一网络设备，这里的第三网络设备在方法500中称为上一个接收gNB，第一网络设备称为接收gNB。
方案1：
S112-a，第二网络设备向终端设备发送第四下行数据，相应地，终端设备接收来自第二网络设备的第四下行数据，第四下行数据为小数据。
S113-a，终端设备向第二网络设备发送第一状态报告，相应地，第二网络设备接收来自终端设备的第一状态报告，第一状态报告用于指示未成功接收第四下行数据。
示例性地，这里的第一状态报告可以与无线链路控制层对应。
需要说明的是，S113-a中并不限定第一状态报告一定是向第二网络设备指示未成功接收的下行数据，这里是以未成功接收第四下行数据为例，介绍本申请实施例如何降低丢包率。例如，第一状态报告中还可以指示终端设备成功接收下行数据B，下行数据B也是由第二网络设备发送给终端设备的。
S114-a，第一网络设备向终端设备发送第一指示信息，相应地，终端设备接收来自第一网络设备的第一指示信息，第一指示信息用于指示第一网络设备支持在小数据包传输过程中避免数据丢失。
示例性地，S114-a之前，终端设备的SDT过程失败。可选地，S114-a之前，方法110还可以包括，终端设备进行小区重选，重选至第一网络设备所在的小区。
应理解，该第一指示信息可以理解为，在S114-a的后续步骤中，如果终端设备要通过第一网络设备与网络设备进行通信，第一网络设备可以支持避免SDT失败之前终端设备和网络侧之间传输的数据丢失。
可以理解的是，在第一网络设备支持在小数据包传输过程中避免数据丢失的情况下，第一网络设备向终端设备发送第一指示信息。示例性地，在第一网络设备不支持在小数据包传输过程中避免数据丢失的情况下，第一网络设备可以向终端设备发送指示信息A，该指示信息A用于指示不支持在小数据包传输过程中避免数据丢失，或者，第一网络设备不发送第一指示信息或指示信息A。那么在该情况下，终端设备可以再次进行小区重选，重选至其他网络设备的小区，重复执行S114-a类似的步骤；或者，终端设备可以进入RRC空闲态，可选地，终端设备发起非SDT过程的恢复过程。
可选地，S114-a之后，第一网络设备可以根据终端设备携带的标识获取终端设备的签约数据向第二网络设备发送第二请求消息，所述第二请求消息用于请求获取所述终端设备的上下文，所述第二请求消息包括用于指示小数据包传输的指示信息；所述第一网络设备接收来自所述第二网络设备的第二响应消息，所述第二响应消息包括用于指示执行锚点重定位的指示信息。可以理解的是，锚点从第二网络设备重定位至第一网络设备，协议栈从第二网络设备迁移至第一网络设备，例如图3中的(b)所示。另外，第二响应消息包括 终端设备的上下文。随后第一网络设备根据终端设备的上下文与终端设备进行SDT过程，第一网络设备在PDCP层保存终端设备的上下文。
可选地，第一网络设备接收来自第二网络设备的第四指示信息，相应地，第二网络设备接收来自第一网络设备的第四指示信息，该第四指示信息用于指示终端设备未成功接收第四下行数据。第一网络设备根据该第四指示信息确定PDCP的发送窗口。PDCP发送窗口的确定方式可以参考S414中的描述。一种可能的实现方式中，第四指示信息承载于第二响应消息中，或者，第四指示信息由S115隐式指示，或者，第四指示信息与第四下行数据一起传输。
方案2：
S112-b-1，第二网络设备向第三网络设备发送第四下行数据，相应地，第三网络设备接收来自第二网络设备的第四下行数据，第四下行数据为小数据。
S112-b-2，第三网络设备向终端设备发送第四下行数据，相应地，终端设备接收来自第三网络设备的第四下行数据。
S113-b-1，终端设备向第三网络设备发送第二状态报告，相应地，第三网络设备接收来自终端设备的第二状态报告，第二状态报告用于指示未成功接收第四下行数据。
示例性地，这里的第二状态报告可以与无线链路控制层对应。
S114-b，具体可以参见方案1中的S114-a的描述，区别在于：S114-a之后可选执行的步骤与S114-b之后可选执行的步骤不同。
可选地，S114-b之后，第一网络设备可以根据终端设备携带的标识获取终端设备的签约数据向第二网络设备发送第三请求消息，所述第三请求消息用于请求获取所述终端设备的上下文，所述第三请求消息包括用于指示小数据包传输的指示信息；所述第一网络设备接收来自所述第二网络设备的第三响应消息，所述第三响应消息包括用于指示不执行锚点重定位的指示信息。可以理解的是，第二网络设备仍然为锚点gNB，协议栈中的RLC、MAC、PHY迁移至第一网络设备，PDCP和SDAP还在第二网络设备，例如图3中的(a)所示。另外，第三响应消息包括SDT上下文，关于SDT上下文的介绍可以参见方法500的S515。
需要说明的是，S114在S113-b-2之前，或者，也可以在S113-b-2之后。
S113-b-2，第三网络设备向第二网络设备发送第一状态报告，相应地，第二网络设备接收来自第三网络设备的第一状态报告，第一状态报告包括用于指示终端设备未成功接收第四下行数据的指示信息。
示例性地，这里的第二状态报告可以与分组数据汇聚层对应。
作为一个示例，S113-b-1和S113-b-2分别可以参考方法100中的S103和S104。
作为另一个示例，S113-b-2之前，步骤1，第二网络设备向第三网络设备发送第四请求消息，相应地，第三网络设备接收来自第一网络设备的第四请求消息。该第四请求消息用于请求第四下行数据的状态报告。S113-b-2中的第一状态报告承载于该请求消息的响应消息中。可选地，该步骤1可以在终端设备小区重选至第一网络设备的小区之前，也可以在终端设备小区重选至第一网络设备的小区之后。示例性地，在终端设备小区重选至第一网络设备的小区之后，S114中的第三请求消息可以理解为触发第二网络设备执行步骤1的触发条件。
可选地，第二网络设备还可以根据第一状态报告确定小区重选之后的PDCP发送窗口，具体可以参见S513中给出的示例。
S115，第二网络设备向第一网络设备发送第四下行数据，相应地，终端设备接收来自第一网络设备的第四下行数据。
S116，第一网络设备向终端设备发送第四下行数据，相应地，终端设备接收来自第一网络设备的第四下行数据。
应理解，S115和S116，第二网络设备通过第一网络设备向终端设备重传第四下行数据。
还应理解，由于在SDT过程中，终端设备发生小区重选时，终端设备会进入RRC空闲态，将不再传输数据包，很可能出现丢包的情况。本申请实施例，在SDT失败之后，通过向终端设备重传未成功被接收的数据，使得终端设备能够获得SDT失败之前为成功接收的数据，从而降低SDT过程中的丢包率。
可选地，第三网络设备在接收第四请求消息之后可以释放与终端设备的链路，停止与终端设备通信。需要说明的是，这里并不限制第三网络设备就在接收第四请求消息之后的下一个步骤就是释放与终端设备的链路，停止与终端设备通信。
示例性地，方法400可以理解为方法110的方案1的一种可能的实现方式，方法500可以理解为方法110的方案2的一种可能的实现方式。
图6示出了本申请提供的数据传输的方法120的示意图。
S121，第二网络设备向终端设备发送第二指示信息，相应地，终端设备接收来自第二网络设备的第二指示信息，所述第二指示信息用于指示小数据包传输过程中允许/使能避免数据丢失。
具体可以参见S111中对应的描述，区别在于将“方法110”替换为“方法120”。
S122，终端设备向第二网络设备发送第四上行数据，相应地，第二网络设备接收来自终端设备的第四上行数据，所述第四上行数据为小数据。
S123，第二网络设备向终端设备发送第三状态报告，相应地，终端设备接收来自第二网络设备的第三状态报告，第三状态报告包括以下指示信息中的至少一项：用于指示成功接收第一上行数据的指示信息，用于指示未成功接收第二上行数据的指示信息，所述第四上行数据包括所述第一上行数据和所述第二上行数据。
应理解，终端设备可以根据第三状态报告确定第四上行数据中哪些数据成功被接收，哪些数据未成功被接收。
示例性地，这里的第三状态报告可以与无线链路控制层对应。
S124，第一网络设备向终端设备发送第一指示信息，相应地，终端设备接收来自第一网络设备的第一指示信息，第一指示信息用于指示第一网络设备支持在小数据包传输过程中避免数据丢失。
具体可以参见S114中对应的描述，区别在于：将“S114”替换为“S124”，将“方法120”替换为“S110”。
S125，第二网络设备向第一网络设备发送第一上行数据，相应地，第一网络设备接收来自第二网络设备的第一上行数据，第一上行数据是第二网络设备成功接收的数据，第一上行数据为小数据。
应理解，由于锚点重定位至第一网络设备，第二网络设备也将SDT失败之前已经成功从终端设备接收的数据发送给第一网络设备。
S126，终端设备向第一网络设备发送第二上行数据，相应地，第一网络设备接收来自终端设备的第二上行数据，第二上行数据是第二网络设备未成功接收的来自终端设备的数据，第二上行数据为小数据。
示例性地，终端设备根据S123中接收的第三状态报告，向第一网络设备重传第二网络设备未成功接收的数据。可以理解的是，通过S125和S126，第一网络设备可以成功接收到终端设备在S122中向第二网络设备发送的第四上行数据。
示例性地，方法300可以理解为方法120的一种可能的实现方式。
应理解，由于在SDT过程中，终端设备发生小区重选时，终端设备会进入RRC空闲态，将不再传输数据包，很可能出现丢包的情况。本申请实施例，在SDT失败之后，通过终端设备重传未成功被第二网络设备接收的数据，以及通过第二网络设备向第一网络设备发送已经从终端设备成功接收的数据，使得第一网络设备能够获得SDT失败之前终端设备发送给第二网络设备的数据，从而降低SDT过程中的丢包率。
图7示出了本申请提供的数据传输的方法200的示意图。下面以第一网络设备为接收g NB(receiving gNB)、第二网络设备为上一个服务的gNB(last serving gNB)、第一下行数据为第一下行SDT数据为例介绍方法200。方法200中，UE可能移动后不在第二网络设备的覆盖范围，通过第一网络设备接入网络。UE发起SDT的恢复过程，由第一网络设备向第二网络设备请求UE的上下文。第二网络设备决定不执行锚点重定位的场景下，通过第一网络设备向第二网络设备提供RLC状态，以便于第二网络设备根据RLC状态调整PDCP的发送窗口。其中，UE、第一网络设备和第二网络设备的协议栈分布可以参见图3中的(a)。
S201，终端设备向第一网络设备发送RRC恢复请求(RRC resume request)消息和上行SDT数据(UL SDT data)，相应地，第一网络设备接收来自终端设备的RRC恢复请求和上行SDT数据01。第一网络设备缓存该上行SDT数据。
或者，S201中的上行SDT数据还可以替换为上行SDT信令(UL SDT signaling)。
S202，第一网络设备向第二网络设备发送获取上下文请求(retrieve UE context request)消息，相应地，第二网络设备接收来自第一网络设备的上下文请求消息，该请求消息中包括SDT指示信息(SDT indicator)。
S203，第二网络设备确定不执行锚点重定位。
例如，第二网络设备可以根据自身的负载等信息，或者，根据接收的来自第一网络设备的信息确定不执行锚点重定位。
S204，第二网络设备向第一网络设备发送SDT上下文迁移(SDT contexttransfer)消息，相应地，第一网络设备接收来自第二网络设备的SDT上下文迁移消息，该消息包括SDT上下文，下行数据转发提案(DL dataforwardingproposal)和DRB级上行传输网络层信息(DRB level DL transport network layerinformation)。
可选地，该消息指示第二网络设备不执行锚点重定位。
第二网络设备还向第一网络设备发送RLC配置，相应地，第一网络设备接收来自第二网络设备的RLC配置，该RLC配置与不执行锚点重定位对应。
第二网络设备还向第一网络设备发送上行数据转发隧道地址，相应地，第一网络设备接收来自第二网络设备的上行数据转发隧道地址。第一网络设备可以根据该上行数据转发隧道地址，将从UE接收的上行数据转发给第二网络设备。
S205，第一网络设备向第二网络设备发送XN-U地址指示信息(XN-U ADDRESS INDICATION)，用于指示下行数据转发隧道地址，相应地，第一网络设备接收来自第一网络设备的上行地址指示信息，该指示信息包括DRB级上行传输网络层信息。第二网络设备可以根据该下行数据转发隧道地址，将要发送给UE的下行数据发送给第一网络设备，随后第一网络设备再将该下行数据转发给UE。
S206，第一网络设备使用上行数据转发隧道地址，向第二网络设备发送上行SDT数据，相应地，第二网络设备接收来自第一网络设备的上行SDT数据。例如，这里的上行数据转发隧道地址可以是在S204中接收的。
S207，第二网络设备向UPF发送上行SDT数据，相应地，UPF接收来自第二网络设备的上行SDT数据。
可选地，S208，UPF向第二网络设备发送第二下行SDT数据，相应地，第二网络设备接收来自UPF的第二下行SDT数据。执行S208的情况下，S209中的第二网络设备处理第二下行SDT数据后得到包括第一下行SDT数据的PDCP PDU；不执行S208的情况下。S209中的第一下行SDT数据可以是第二网络设备内部缓存的。
S209，第二网络设备使用下行数据转发隧道地址(S205中接收的)向第一网络设备发送包括第一下行SDT数据的PDCP PDU，相应地，第一网络设备接收来自第二网络设备的PDCP PDU。第一网络设备处理该PDCP PDU，得到RLC PDU，该RLC PDU包括第一下行SDT数据。
S210，第一网络设备向UE发送该RLC PDU，相应地，UE接收来自第一网络设备的RLC PDU。
S211，UE向第一网络设备发送该RLC PDU的RLC状态，相应地，第一网络设备接收来自UE的RLC状态，该RLC状态用于指示成功接收或未成功接收第一下行SDT数据。
例如，UE成功接收到第一SDT数据，未成功接收到第二SDT数据。UE可以通过发送RLC反馈(feedback)消息来向第一网络设备上报RLC状态，在RLC反馈消息中，ACK表示成功接收第一下行SDT数据，非确认(negative acknowledgement，NACK)表示未成功接收第一下行SDT数据。这里的RLC状态可以理解为方法100中的第一反馈消息的一种具体示例。
S212，第一网络设备向第二网络设备发送该PDCP PDU的RLC状态，相应地，第二网络设备接收来自第一网络设备的RLC状态。这里的RLC状态可以理解为方法100中的第二反馈消息的一种具体示例。
该RLC状态可以携带第一下行SDT数据的PDCP SN。可选地，该RLC状态还可以携带RB标识。应理解，同一个RB承载的下行SDT数据的PDCP SN可能相同，携带RB标识更准确地标识第一下行SDT数据。
示例性地，该RLC状态是通过控制面消息进行传输的。
例如，第一网络设备可以通过发送RLC反馈消息来向第一网络设备上报RLC状态，在RLC反馈消息中，ACK表示UE成功接收第一下行SDT数据，NACK表示UE未成功 接收第一下行SDT数据。
关于何时执行S212，可以有如下几种实现方式：
实现方式一：
第一网络设备设置一个定时器，该定时器超时时第一网络设备向第二网络设备反馈RLC状态，例如执行S212，该定时器可以是在第一网络设备执行S211之后启动的，或者，也可以是第一网络设备接收到其他RLC状态报告后启动的。该定时器的定时时长可以是由第一网络设备确定的。例如这里的其他RLC状态报告可以指示第三下行SDT数据成功接收，第三下行SDT数据和第一下行SDT数据不同。
需要说明的是，这里的定时器与上文介绍技术用语部分提及的窗口推动定时器不同。窗口推动定时器是在锚点gNB(在方法200中为第二网络设备)的。其作用在于，当窗口推动定时器超时，锚点gNB会推动PDCP的发送窗口。这里的定时器不是在锚点gNB，是在第一网络设备的。该定时器的作用是，定时器超时，第一网络设备要向第二网络设备反馈RLC状态。
实现方式二：
终端设备向第一网络设备发送一个或多个RLC PDU的RLC状态，相应地，第一网络设备接收来自终端设备的一个或多个RLC PDU的RLC状态。第一网络设备根据该一个或多个RLC PDU的RLC状态确定终端设备已经成功接收了M个PDCP PDU，M≥N的情况下，或者说，第一网络设备根据该一个或多个RLC PDU的RLC状态确定终端设备成功接收的PDCP PDU的数量已经达到了第一阈值的情况下，例如该第一阈值为N，那么第一网络设备向第二网络设备发送N个PDCPPDU的RLC状态。其中，N为正整数。
这里的N可以是是第二网络设备指示的，这里的N可以理解为一个阈值，例如第一阈值。示例性地，可以在步骤S204中由第二网络设备向第一网络设备指示的。
相比于第一网络设备每确定终端设备成功接收一个RLC PDU就向第二网络设备发送一个PDCP PDU的RLC状态的方式，实现方式二可以降低信令开销。
可选地，该N个PDCP PDU的PDCP SN是连续的。
例如，第二网络设备发送第一SDT数据时的发送窗口为[1,99]，N为3，第一SDT数据的PDCP SN为3，该一个或多个RLC状态还用于指示终端设备成功接收了SDT数据A和SDT数据B，该SDT数据A的PDCP SN为2，该SDT数据B的PDCP SN为1，那么第一网络设备向第二网络设备发送的RLC状态指示成功接收N个PDCP PDU。
第一网络设备给第二网络设备的PDCP PDU的SN是连续的情况可以是，第一网络设备根据该多个RLC PDU的RLC状态确定终端设备成功接收了0，1，2，3，4。那么第一网络设备在S213中能将PDCP的发送窗口的起始SN调整至5。
S213，第二网络设备根据S212中接收的RLC状态，推动PDCP的发送窗口。
例如，将执行S213之前的PDCP发送窗口称为第一发送窗口，将执行S213之后的PDCP发送窗口称为第二发送窗口，第一发送窗口包括第一SDT数据的PDCP SN，例如，推动之前的发送窗口为[1,99]，推动之前第一SDT数据的PDCP SN为3。第二网络设备执行S213之前，需要确定将PDCP的发送窗口往前推动几个比特位，换句话说，需要确定推动后的PDCP发送窗口的起始SN。这里的起始SN可以是第一发送窗口中未被终端设备成功接收的数据中，PDCP SN排在第一个的数据。例如，[1,99]中PDCP SN分别为4， 6-8，10-99的数据未被终端设备成功接收，那么起始SN可以为4。或者，这里的起始SN可以是第一发送窗口中被终端设备成功接收的数据中，前L个PDCP SN连续的数据的下一个PDCP SN。例如，[1,99]中PDCP SN分别为1，2，3，5，6，7的数据被终端设备成功接收，起始SN可以为4。
进一步地，第二终端设备可以确定PDCP发送窗口的范围，即发送窗口的起始SN和末尾SN。发送窗口的末尾SN可以根据以下方式计算：将起始SN与发送窗口的长度(length)的和对SN的长度取余，得到的余数即为末尾SN。例如，PDCP的发送窗口的起始SN为5，假设发送窗口的长度为4个比特位，SN的长度为8个比特位，其中，起始SN与发送窗口的长度的和为9，9对8取余得到1，那么末尾SN即为下一个SN周期的1。
例如，这里提到的PDCP SN也可以用二进制标识，0可以表示为00001，1可以表示为0001，2可以表示为0010，3可以表示为0011，4可以表示为0100。本申请中涉及的PDCP SN都可以用上述方式表示，在这里进行统一说明，其余地方不多赘述。
S214，第二网络设备向第一网络设备发送获取UE上下文失败消息，相应地，第一网络设备接收来自第二网络设备的获取UE上下文失败消息。
例如，该消息可以承载于RRC释放(release)消息中。
S215，第一网络设备向终端设备发送RRC释放消息，相应地，终端设备接收来自第一网络设备的RRC释放消息。随后，终端设备终止SDT过程。
上述方案，通过gNB之间交互RLC状态报告，即第一网络设备向第二网络设备(锚点gNB)发送RLC状态报告，第二网络设备可以根据UE的RLC状态决定如何调整PDCP发送窗口，从而本申请实施例对于锚点gNB何时推动PDCP窗口给出了解决方案。
图8示出了本申请提供的数据传输的方法300的示意图。下面以第一网络设备为接收g NB(receiving gNB)、第二网络设备为上一个服务的gNB(last serving gNB)、第一上行数据为数据1和3、第二上行数据为数据2和4、第三上行数据为数据5，6，7，8以及第四上行数据为上行SDT数据为例介绍方法300。方法300中，UE向第二网络设备发送上行数据后进行小区重选，重选到第一网络设备的小区。UE发起SDT的恢复过程，由第一网络设备向第二网络设备请求UE的上下文。第二网络设备决定执行锚点重定位的场景下，第二网络设备向第一网络设备提供RLC状态，使得第一网络设备根据RLC状态调整PDCP的接收窗口，第一网络设备可以成功接收到UE重传的上行数据，降低上行数据的丢包率。UE、第一网络设备和第二网络设备的协议栈分布可以参见图3中的(b)。
S301，第二网络设备向UE发送RRC释放消息，相应地，UE接收来自第二网络设备的RRC释放消息。该消息中包括第二指示信息，该第二指示信息用于指示SDT过程中允许/使能避免数据丢失。该第二指示信息还可以理解为用于向UE指示后续进行的SDT过程中，如果发生小区重选，第二网络设备支持避免上行数据的丢失的机制，具体地，该机制包括步骤S302-S319。示例性地，这里的第二指示信息可以表示为a flag to enable avoidance of data loss。
S302，UE发起SDT过程，UE向第二网络设备发送RRC恢复请求1(RRC resume request)消息，相应地，第二网络设备接收来自UE的RRC恢复请求1消息。该RRC恢复请求1消息中包括第一恢复(resume)消息认证码-完整性(message authentication code–integrity，MAC-I)。
UE和第一网络设备启动SDT失败检测定时器。该失败检测定时器如果超时，UE的RRC进入空闲态，随后会发起非SDT的恢复流程。因此，这里的SDT失败检测定时器与上文技术用语部分的窗口推动定时器不同。
S303，UE向第二网络设备发送上行SDT数据，相应地，第二网络设备接收来自UE的上行SDT数据，该上行SDT数据包括数据1，2，3，4。其中，1，2，3，4分别为上行SDT数据的PDCP SN。
示例性地，S303中的上行SDT数据可以与S302中的RRC恢复请求消息1一起发送，例如该上行SDT数据承载于RRC恢复请求消息1中，上行SDT数据可以与S302中的RRC恢复请求消息1也可以分开发送。
S304，第二网络设备向UE发送RLC状态报告，相应地，UE接收来自第二网络设备的RLC状态报告，该报告指示成功接收或未成功接收上行SDT数据。例如，第二网络设备成功接收到第一SDT上行数据，未成功接收到第二SDT上行数据。该报告可以指示成功接收第一SDT上行数据(第一数据的SN为x，x为自然数)，未成功接收第二SDT上行数据(第二SDT上行数据的SN是x+1)。再例如，该报告指示成功接收数据1，3；未成功接收数据2，4。
S305，UE确定SDT失败，例如，UE进行小区重选，重选到第一网络设备的小区。
S306，第一网络设备向UE发送系统信息块1，相应地，UE接收来自第一网络设备的系统信息块1，该系统信息块1携带SDT配置和第一指示信息，该SDT配置用于指示用于SDT的随机接入的时频资源，该第一指示信息用于指示SDT过程中支持避免数据丢失的机制，该机制包括S307-S319。这里的第一指示信息还可以承载于其他消息中发送，本申请对此并不做限定。示例性地，这里的第一指示信息可以表示为support indication for avoidance of data loss。
UE和第一网络设备重新启动SDT失败检测定时器。
需要说明的是，系统信息块1中如果未携带第一指示信息，或者，该系统信息块1中携带另一个指示信息，该另一个指示信息用于指示SDT过程中不支持避免数据丢失，那么UE会进入空闲态或者继续进行小区重选，也就是说，后续步骤S307-S319将不会执行。
S307，UE向第一网络设备发送RRC恢复请求2消息，相应地，第一网络设备接收来自UE的RRC恢复请求2消息，该消息中包括第二resume MAC-I，第二resume MAC-I与第一resume MAC-I不同。
S308，第一网络设备向第二网络设备发送获取上下文请求消息，相应地，第二网络设备接收来自第一网络设备的获取上下文请求消息。
S309，第二网络设备确定执行锚点重定位。
例如，第二网络设备可以根据自身的负载等信息，或者，根据接收的来自第一网络设备的信息确定执行锚点重定位。
S310，第二网络设备向第一网络设备发送获取UE上下文响应(retrieve UE context response)消息，相应地，第一网络设备接收来自第二网络设备的获取UE上下文响应消息。该响应消息中包括超帧号(hyper frame number，HFN)、PDCP SN，这里的PDCP SN用于确定PDCP接收窗口，这里的HFN用于加密网络与终端设备之间传输的数据。这里的HFN和SN可以是网络接收来自终端设备的数据的HFN和PDCP SN。例如，该响应消 息中包括第二SDT上行数据的HFN和PDCP SN。
可选地，该消息指示第二网络设备执行锚点重定位。
第一网络设备可以根据该响应信息确定PDCP接收窗口。其中，确定PDCP接收窗口可以理解为确定PDCP接收窗口的范围，即PDCP接收窗口的起始SN和末尾SN。其中，接收窗口的起始SN为响应消息中包括的PDCP SN。接收窗口的末尾SN可以根据以下方式计算：将起始SN与接收窗口的长度的和对SN的长度取余，得到的余数即为末尾SN。可选地，如果响应消息包括多个PDCP SN，可以将接收顺序排在第一个的SN作为PDCP接收窗口的SN。例如，该响应消息中包括第二SDT上行数据的PDCP SN，为2和4，PDCP的接收窗口的起始SN为2，假设接收窗口的长度(length)为4个比特位，SN的长度为8个比特位，其中，起始SN与接收窗口的长度的和为6，6对8取余得到6，那么末尾SN即为当前SN周期的6。
上述方案，在SDT失败的情况下，通过第二网络设备向第一网络设备(锚点gNB)发送状态报告，第一网络设备根据状态决定如何调整PDCP接收窗口，以及调整后的PDCP接收窗口的范围，从而本申请实施例对于锚点gNB何时推动PDCP窗口给出了解决方案。
S311，第一网络设备向AMF发送路径切换请求(pathswitchrequest)消息，相应地，AMF接收来自第一网络设备的路径切换请求消息。该路径切换请求消息用于请求AMF将UPF与第二网络设备的连接切换到UPF与第一网络设备的连接。进行路径切换后，网络要发送给UE的下行数据都是由UPF直接发送给第一网络设备，而不是由UPF发送给第二网络设备。
S312，AMF向第一网络设备发送路径切换确认(path switch acknowledge)消息，相应地，第一网络设备接收来自AMF的路径切换确认消息。
S313，具体可以参见方法200中的S205。
S314，第二网络设备使用下行转发隧道地址(S313中接收的)向第一网络设备转发(forwarding)上述第一SDT上行数据，相应地，第一网络设备接收来自第二网络设备转发的第一SDT上行数据。例如，第二网络设备向第一网络设备发送PDCP SDU，该PDCP SDU包括数据1，3。
应理解，第二网络设备向第一网络设备转发第一SDT上行数据，可以隐式指示第一SDT上行数据是成功接收的。或者，第二网络设备还可以显示地指示第一网络设备该第一SDT上行数据是成功接收的，比如，第二网络设备可以将S304中发送给UE的状态报告指示的内容发送给第一网络设备。
上述方案，通过第二网络设备将已经成功接收的上行数据转发给第一网络设备，可以节省信令开销。
S315，UE向第一网络设备重传第二SDT上行数据，相应地，第一网络设备接收来自UE的第二SDT上行数据。由于第二SDT上行数据(数据2，4)的SN是在上述的接收窗口内，所以该数据是有效的数据。然后第一网络设备将第二SDT上行数据与第一SDT上行数据按照PDCP SN进行排序。
第一网络设备按序递交(in-orderdelivery)给PDCP以上的协议层。
由于在SDT过程中，UE发生小区重选时，UE会进入RRC空闲态，将不再传输数据包，很可能出现丢包的情况。本申请实施例，在小区重选之后，通过UE重传未成功被第 二网络设备接收的数据，可以降低丢包率。
S316，第一网络设备向AMF按序转发上行SDT数据(数据1，2，3，4)，相应地，AMF接收来自第一网络设备的上行SDT数据。
S318，第一网络设备向UE发送RRC释放消息，相应地UE接收来自第一网络设备的RRC释放消息。UE终止SDT过程。
S319，第一网络设备向第二网络设备发送UE上下文释放消息，相应地，第二网络设备接受来自第一网络设备的UE上下文释放消息。第二网络设备释放UE上下文，终止与UE的通信。
可选地，S315中，UE还可以向第一网络设备发送第三上行SDT数据，例如PDCP SN号为5，6，7，8的数据。相应地，第一网络设备接收来自UE的第三上行SDT数据。其中，S303中UE向第二网络设备发送数据1，2，3，4时使用的密钥与S315中UE向第一网络设备发送数据5，6，7，8时使用的密钥不同。
图9出了本申请提供的数据传输的方法400的示意图。下面以第一网络设备为接收g NB(receiving gNB)、第二网络设备为上一个服务的gNB(last serving gNB)、第四下行数据为第二下行SDT数据(数据2和4)、第六下行数据为数据5、6、7、8为例介绍方法400。方法400中，UE接收来自第二网络设备的下行数据后进行小区重选，重选到第一网络设备的小区。UE发起SDT的恢复过程，由第一网络设备向第二网络设备请求UE的上下文。第二网络设备决定执行锚点重定位的场景下，向第一网络设备反馈RLC状态，使得第一网络设备根据RLC状态调整PDCP的发送窗口。第二网络设备向第一网络设备重传UE未成功接收的数据，第一网络设备向UE发送该重传的数据，以便降低下行数据的丢包率。UE、第一网络设备和第二网络设备的协议栈分布可以参见图3中的(b)。
S401-S402，具体可以参见S301-S302的描述。
S403，第二网络设备向UE发送下行SDT数据，相应地，UE接收来自第二网络设备的下行SDT数据。该下行SDT数据包括数据1，2，3，4。其中，1，2，3，4分别为下行SDT数据的PDCP SN。
S404，UE向第二网络设备发送RLC状态报告，相应地，第二网络设备接收来自UE的RLC状态报告。例如，UE成功接收到第一下行SDT数据，未成功接收到第二下行SDT数据。该报告可以指示成功接收第一下行SDT数据(例如第一数据的SN为x，x为自然数)，未成功接收第二下行SDT数据(例如第二下行SDT数据的SN是x+1)。再例如，该报告指示成功接收数据1，3；未成功接收数据2，4。
S405-S409，具体可以参见S305-S309的描述。
S410，第二网络设备向第一网络设备发送获取UE上下文响应(retrieve UE context response)消息，相应地，第一网络设备接收来自第二网络设备的获取UE上下文响应消息。
S411-S413可以参见S311-S313的描述。
S414，第二网络设备根据S413中提供的下行转发隧道地址向第一网络设备转发第二下行SDT数据，相应地，第一网络设备接收来自第二网络设备第二下行SDT数据。
应理解，第二网络设备向第一网络设备转发第二下行SDT数据，可以隐式指示第一下行SDT数据是未成功接收的。或者，第二网络设备还可以显示地指示第一网络设备该 第二下行SDT数据是未成功接收的，比如第二网络设备向第一网络设备发送RLC状态报告，该状态报告用于指示UE成功接收第一下行SDT数据，未成功接收第二下行SDT数据，该状态报告是根据S404中第二网络设备从UE接收的RLC状态报告确定的。
第一网络设备根据第二下行SDT数据的PDCP SN可以确定PDCP发送窗口。PDCP发送窗口的确定方式可以参考S310中确定PDCP接收窗口的描述，区别在于：将接收窗口替换为发送窗口，将第二上行SDT数据替换为第二下行SDT数据。
上述方案，在SDT失败的情况下，通过第二网络设备向第一网络设备(锚点gNB)发送状态报告，第一网络设备根据状态决定如何调整PDCP发送窗口，从而本申请实施例对于锚点gNB何时推动PDCP窗口给出了解决方案。
S415，第一网络设备向UE重传第二下行SDT数据，相应地，UE接收来自第一网络设备的第二下行SDT数据。由于第二下行SDT数据(数据2，4)的SN是在上述的发送窗口内，所以该数据是有效的数据。然后UE将第二下行SDT数据与第一下行SDT数据按照PDCP SN进行排序。
UE按序递交(in-order delivery)给PDCP以上的协议层。
由于在SDT过程中，UE发生小区重选时，UE会进入RRC空闲态，将不再传输数据包，很可能出现丢包的情况。本申请实施例，在小区重选之后，通过锚点gNB(第一网络设备)重传未成功被UE接收的数据，可以降低丢包率。
S416-S417，具体可以参见S317-S318的描述。
可选地，方法400还可以包括：
S410中，该响应消息中包括尚未分配或使用的PDCP SN，例如该SN＝x+k，k为大于1的整数。例如，1，2，3，4是已经分配并使用的PDCP SN，该响应消息中的PDCP SN可以是下一个尚未分配或使用的PDCP SN，即5。
S415中，第一网络设备还可以向UE发送第三下行SDT数据，该第三下行SDT数据的PDCP SN是在第一下行SDT数据和第二下行SDT数据之后的，例如数据5，6，7，8。这里的第三下行SDT数据的第一个数据包的PDCP SN是根据S410中的响应消息指示的尚未分配或使用的PDCP SN确定的。
下面结合图10和图11介绍本申请提供的数据传输的方法500。
图10示出了本申请提供的数据传输的方法500的示意性流程图。其中第二网络设备为lastservinggNB，第一网络设备为receivinggNB，第三网络设备为上一个接收的gNB(lastreceivinggNB)。如图10所示，UE不在第二网络设备的覆盖范围内，UE向第三网络设备发起SDT恢复过程，第三网络设备向第二网络设备请求UE的上下文，第二网络设备决定不执行锚点重定向，UE与第二网络设备之间通过第三网络设备进行通信。第一网络设备向第三网络设备发送数据1，2，3，4，第三网络设备向UE发送数据1，2，3，4。UE向第三网络设备反馈第一RLC状态报告，该RLC状态报告指示UE成功接收数据1，3，未成功接收数据2，4。随后，UE进行小区重选，重选至第一网络设备所在的小区，并向第一网络设备发起SDT的恢复过程，由第一网络设备向第二网络设备请求UE的上下文。第二网络设备决定不执行锚点重定位的场景下，第二网络设备通过第三网络设备获取了UE的RLC状态报告，并向第一网络设备反馈UE成功或未成功接收数据的情况，以便第一网络设备推动PDCP发送窗口。第二网络设备向第一网络设备转发数据2，4，第二 网络设备向UE重传数据2，4，可以降低下行数据的丢包率。其中，UE进行小区重选之前，UE、第三网络设备和第二网络设备的协议栈分布可以参见图3中的(a)，UE进行小区重选之后，UE、第一网络设备和第二网络设备的协议栈分布也可以参见图3中的(a)。
图11示出了本申请提供的数据传输的方法500的示意性框图。下面以第一网络设备为第五下行数据为数据1和3、第四下行数据为数据2和4、第六下行数据为数据5、6、7、8为例介绍方法500。
S501-S502，具体可以参见S401-S402的描述，区别在于：将S401中的RRC释放消息替换为第一RRC释放消息；将S402中的第二网络设备替换为第三网络设备。
S503-S505，具体可以参见S202-S204的描述，区别在于：将S202-S204中的第一网络设备替换为第三网络设备，将S202-S204中的“获取上下文请求消息”替换为“获取上下文请求消息1”，将S202-S204中的“SDT上下文”替换为“SDT上下文1”。
S506，第二网络设备通过第三网络设备向UE发送下行SDT数据。其中，第二网络设备向第三网络设备发送下行SDT数据，相应地，第三网络设备接收来自第二网络设备的下行SDT数据。第三网络设备向UE发送下行SDT数据，相应地，UE接收来自第三网络设备的下行SDT数据。该下行SDT数据包括数据1，2，3，4。其中，1，2，3，4分别为下行SDT数据的PDCP SN。
S507可以参见S404的描述，区别在于：将S404中的第二网络设备替换为第三网络设备。
S508-S509，可以参见S405-S406对应的描述。
S510-S511可以参见S202-S203的描述。
应理解，这里第二网络设备没有执行锚点重定位，因此PDCP协议层还在第二网络设备，PDCP层中包括UE的上下文，因此第一网络设备在S510中向第二网络设备发送获取UE上下文请求2。
S512，第二网络设备向第三网络设备发送RLC状态报告请求消息，相应地，第三网络设备接收来自第一网络设备的RLC状态报告请求消息。该消息用于请求UE的RLC状态报告。
S513，第三网络设备向第二网络设备发送第二RLC状态报告，相应地，第二网络设备接收来自第三网络设备的第二RLC状态报告，该状态报告中需要指示SDT数据的逻辑信道号或RB索引(index)，以及PDCP SN或RLC SN。
例如，UE成功接收到第一下行SDT数据，未成功接收到第二下行SDT数据。该报告可以指示成功接收第一下行SDT数据，未成功接收第二下行SDT数据。并携带第一下行SDT数据和第二下行SDT数据的逻辑信道号或承载第一下行SDT数据和第二下行SDT数据的RB索引，以及第一下行SDT数据和第二下行SDT数据的PDCP SN或RLC SN。
应理解，第二网络设备在S510中接收第一网络设备的获取UE上下文请求2后，获知UE重选至第一网络设备的小区。第二网络设备通过S512和S513获取UE的RLC状态，可以根据UE的RLC状态报告调整PDCP的发送窗口，以及在后续步骤中通过第一网络设备向UE重传UE未成功接收的下行数据。
第二网络设备调整PDCP的发送窗口的方式可以参考方法400中步骤S414中第一网络设备调整PDCP的发送窗口的方式。
上述方案，UE先后通过第三网络设备和第一网络设备与第二网络设备传输数据，由作为锚点gNB的第二网络设备协商第三网络设备和第一网络设备之间的状态报告，即从第三网络设备获取状态报告，第一网络设备根据第三网络设备提供的RLC状态决定如何调整PDCP发送窗口，从而本申请实施例对于锚点gNB何时推动PDCP窗口给出了解决方案。
S514，第三网络设备释放与UE的连接，停止与UE的通信。
S514也可以在S512之后S513之前进行，或者，可以在S513之后的任意步骤进行，本申请并不限定。
S515，第二网络设备向第一网络设备发送获取UE上下文响应(retrieve UE context response)消息，相应地，第一网络设备接收来自第二网络设备的获取UE上下文响应消息。该消息可以携带PDCP的配置以及PDCP的发送窗口信息(例如下一个发送的PDCP SN)和PDCP的状态报告，PDCP的状态报告用于指示那些数据已经被终端设备确认成功接收。
可选地，该消息指示第二网络设备不执行锚点重定位。
S516，具体可以参见S413的描述。
S517，第二网络设备根据S516中提供的下行转发隧道地址向第一网络设备转发下行数据，相应地，第一网络设备接收来自第二网络设备的下行数据，即上述第二下行SDT数据。
应理解，第二网络设备向第一网络设备转发第二下行SDT数据，可以隐式指示第一下行SDT数据是未成功接收的。或者，第二网络设备还可以显示地指示第一网络设备该第二下行SDT数据是未成功接收的，比如第二网络设备向第一网络设备发送RLC状态报告，该状态报告用于指示UE成功接收第一下行SDT数据，未成功接收第二下行SDT数据，该状态报告是根据S513中第二网络设备从第三网络设备接收的第二RLC状态报告确定的。
由于在SDT过程中，UE发生小区重选时，UE会进入RRC空闲态，将不再传输数据包，很可能出现丢包的情况。本申请实施例，在小区重选之后，通过UE重传未成功被第二网络设备接收的数据，可以降低丢包率。
S518，第一网络设备向UE重传第二下行SDT数据，相应地，UE接收来自第一网络设备的第二下行SDT数据。由于第二下行SDT数据(数据2，4)的SN是在上述的发送窗口内，所以该数据是有效的数据。然后UE将第二下行SDT数据与第一下行SDT数据按照PDCP SN进行排序。
UE按序递交(in-order delivery)给PDCP以上的协议层。
S519，第一网络设备通过第三网络设备向UE发送第二RRC release消息。第一网络设备向第三网络设备发送第二RRC release消息，相应地，第三网络设备接收来自第一网络设备的第二RRC release消息。第三网络设备向UE发送第二RRC release消息，相应地，UE接收来自第三网络设备的第二RRC release消息。
在收到该消息后，终端设备终止SDT过程。
可选地，S518中，第一网络设备还可以向UE发送第三下行SDT数据，该第三下行SDT数据的PDCP SN是在第一下行SDT数据和第二下行SDT数据之后的，例如数据5， 6，7，8。这里的第三下行SDT数据的第一个数据包的PDCP SN是根据S515中的PDCP的发送窗口信息确定的。
下面介绍本申请提供的数据传输的方法600。
方法600可以与方法100至120，方法200至500中任一个方法结合。在方法300至方法500中，UE都已经进行了小区重选，那么在方法600中，UE可以统计在SDT过程中进行小区重选的次数。在方法200中，UE未进行小区重选，UE在后续的SDT过程中如果进行小区重选也可以根据方法600统计小区重选的次数。当UE统计的在SDT过程中进行小区重选的次数大于或等于一个预设值Y时，Y为正整数，UE进入空闲态，或者，发起非SDT的恢复过程。其中，UE进行一次小区重选，可以理解为一次SDT失败。
S601，UE获取预设值Y。
预设值Y可以是网络设备通过RRC释放消息发送给UE的，相应地，UE接收来自w网络设备的RRC释放消息，该消息中指示SDT过程中最大的小区重选次数Y。
这里的网络设备可以是前述方法中的锚点网络设备。
S602，UE在接收该RRC释放消息后，进入非激活态，保存接入层(accessstratum，AS)上下文。
S603，UE发起SDT过程，在该过程中，由于移动性，终端设备可能进行一次或多次的小区重选，UE记录小区重选的次数。
S604，在小区重选的次数达到Y时，UE停止小区重选，或者，UE直接切换到空闲态，释放所有的AS上下文，或者，UE发起非SDT的恢复过程。
本申请实施例，通过为UE小区重选的次数设置阈值，并由UE统计小区重选次数，当小区重选的次数达到阈值时，停止小区重选或者切换到空闲态或者发起非SDT恢复过程，减少持续的SDT失败而导致的通信效率降低的情况，提高通信效率。
图12是本申请实施例提供的一种数据传输的装置600的示意图。该装置600包括收发单元610，收发单元610可以用于实现相应的通信功能。收发单元610还可以称为通信接口或通信单元。
可选地，该装置600还可以包括处理单元620，处理单元620可以用于进行数据处理。
可选地，该装置600还包括存储单元，该存储单元可以用于存储指令和/或数据，处理单元620可以读取存储单元中的指令和/或数据，以使得装置实现前述各个方法实施例中通信设备(如终端设备，又如网络设备)执行的动作。
该装置600可以用于执行上文各个方法实施例中通信设备(如终端设备，又如网络设备)所执行的动作，这时，该装置600可以为通信设备(如终端设备，又如网络设备)的组成部件，收发单元610用于执行上文方法实施例中通信设备(如终端设备，又如网络设备)侧的收发相关的操作，处理单元620用于执行上文方法实施例中通信设备(如终端设备，又如网络设备)侧的处理相关的操作。
作为一种设计，该装置600用于执行上文各个方法实施例中终端设备所执行的动作。
一种可能的实现方式，收发单元610，用于接收来自第二网络设备的第二指示信息，该第二指示信息用于指示小数据包传输过程中避免数据丢失；还用于接收第四下行数据，该第四下行数据为小数据；还用于发送用于指示未成功接收该第四下行数据的指示信息；还用于接收来自第一网络设备的第一指示信息，该第一指示信息用于指示该第一网络设备 支持在小数据包传输过程中避免数据丢失；还用于接收来自该第一网络设备的第四下行数据。
可选地，收发单元610，具体用于接收来自该第二网络设备的该第四下行数据；收发单元610，具体用于向该第二网络设备发送第一状态报告，该第一状态报告包括该指示信息。
可选地，收发单元610，具体用于接收来自该第三网络设备的该第四下行数据；收发单元610，具体用于向第三网络设备发送第二状态报告，该第二状态报告包括该指示信息。
可选地，收发单元610，还用于接收来自该网络设备的无线资源控制释放消息，该无线资源控制释放消息包括Y，Y为小数据包传输过程中小区重选的次数，Y为正整数；处理单元620，用于发起小数据包传输过程；该终端设备记录小区重选的次数；在该装置记录的小区重选的次数≥Y的情况下，处理单元620，还用于切换至无线资源控制空闲态，或者，收发单元610，还用于向网络设备发送非小数据包传输的恢复请求消息。
另一种可能的实现方式，收发单元610，用于接收来自第二网络设备的第二指示信息，该第二指示信息用于指示小数据包传输过程中避免数据丢失；收发单元610，还用于向该第二网络设备发送第四上行数据，该第四上行数据为小数据；收发单元610，还用于接收来自该第二网络设备的第三状态报告，该第三状态报告包括以下指示信息中的至少一项：用于指示成功接收第一上行数据的指示信息，用于指示未成功接收第二上行数据的指示信息，其中，该第四上行数据包括该第一上行数据和该第二上行数据；收发单元610，还用于接收来自第一网络设备的第一指示信息，该第一指示信息用于指示该第一网络设备支持在小数据包传输过程中避免数据丢失；收发单元610，还用于向该第一网络设备发送该第二上行数据。
应理解，各单元执行上述相应步骤的具体过程在上述各方法实施例中已经详细说明，为了简洁，在此不再赘述。
作为另一种设计，该装置600用于执行上文各个方法实施例中第一网络设备所执行的动作。
一种可能的实现方式，收发单元610，用于接收来自第二网络设备的第一下行数据，该第一下行数据为小数据；还用于向终端设备发送该第一下行数据；还用于接收来自该终端设备的第一反馈消息，该第一反馈消息用于指示成功或未成功接收该第一下行数据，该一反馈消息对应第一协议层；还用于根据该第一反馈消息向该第二网络设备发送第二反馈消息，该第一反馈消息用于指示成功接收该第一下行数据的情况下，该第二反馈消息用于指示该终端设备成功接收该第一下行数据，该第二反馈消息对应第二协议层。
示例性地，该第一反馈消息包括以下至少一项：该第一下行数据在该第一协议层的序列号、承载该第一下行数据的无线承载的标识、承载该第一下行数据的逻辑信道的标识，该第二反馈消息包括以下至少一项：该第一下行数据在该第二协议层的序列号、该第一下行数据在该第一协议层的序列号、承载该第一下行数据的无线承载的标识、承载该第一下行数据的逻辑信道的标识。
可选地，处理单元620，用于根据该第一反馈消息启动定时器。
可选地，该定时器超时的情况下，收发单元610，还用于根据该第一反馈消息向该第二网络设备发送第二反馈消息。
可选地，处理单元620具体用于根据该第一反馈消息确定终端设备成功接收该第一协议层的M个数据，M为正整数；当该M个数据中，第二协议层的序列号连续的数据的个数大于或等于N时，收发单元610，具体用于向该第二网络设备发送第二反馈消息，该第二反馈消息用于指示该终端设备成功接收该第二协议层的N个数据，该N个数据包括该第一下行数据，该N为正整数。
示例性地，该第一协议层为无线链路控制层，该第二协议层为分组数据汇聚层。
可选地，收发单元610，还用于向该第二网络设备发送第一请求消息，该第一请求消息用于请求获取该终端设备的上下文，该第一请求消息包括用于指示小数据包传输的指示信息；收发单元610，还用于接收来自该第二网络设备的第一响应消息，该第一响应消息包括用于指示不执行锚点重定位的指示信息。
可选地，收发单元610，还用于向该终端设备发送第一指示信息，该第一指示信息用于指示该第一网络设备支持在小数据包传输过程中避免数据丢失；收发单元610，还用于接收来自第二网络设备的第四下行数据，该第四下行数据为该终端设备未成功接收的数据，该第四下行数据为小数据；收发单元610，还用于向该终端设备发送该第四下行数据。
可选地，收发单元610，还用于向该第二网络设备发送第二请求消息，该第二请求消息用于请求获取该终端设备的上下文，该第二请求消息包括用于指示小数据包传输的指示信息；收发单元610，还用于接收来自该第二网络设备的第二响应消息，该第二响应消息包括用于指示执行锚点重定位的指示信息。
可选地，收发单元610，还用于向该第二网络设备发送第三请求消息，该第三请求消息用于请求获取该终端设备的上下文，该第三请求消息包括用于指示小数据包传输的指示信息；收发单元610，还用于接收来自该第二网络设备的第三响应消息，该第三响应消息包括用于指示不执行锚点重定位的指示信息。
可选地，收发单元610，还用于向该终端设备发送无线资源控制释放消息，该无线资源控制释放消息包括Y，Y为小数据包传输过程中小区重选的次数，Y为正整数。
另一种可能的实现方式，收发单元610，用于向终端设备发送第一指示信息，该第一指示信息用于指示该第一网络设备支持在小数据包传输过程中避免数据丢失；该第一网络设备接收来自第二网络设备的第一上行数据，该第一上行数据是该第二网络设备成功接收的数据，该第一上行数据为小数据；收发单元610，还用于接收来自该终端设备的第二上行数据，该第二上行数据是该第二网络设备未成功接收的来自该终端设备的数据，该第二上行数据为小数据。
可选地，收发单元610，还用于向该第二网络设备发送第二请求消息，该第二请求消息用于请求获取该终端设备的上下文，该第二请求消息包括用于指示小数据包传输的指示信息；收发单元610，还用于接收来自该第二网络设备的第二响应消息，该第二响应消息用于指示第二网络设备决定执行锚点重定位。
应理解，各单元执行上述相应步骤的具体过程在上述各方法实施例中已经详细说明，为了简洁，在此不再赘述。
作为另一种设计，该装置600用于执行上文各个方法实施例中第二网络设备所执行的动作。
一种可能的实现方式，收发单元610，用于向第一网络设备发送第一下行数据，该第 一下行数据为小数据，该第一网络设备用于将该第一下行数据发送给终端设备；收发单元610，还用于接收来自该第一网络设备的第二反馈消息，该第二反馈消息用于指示终端设备成功接收或未成功接收该第一下行数据，该第二反馈消息与第二协议层对应；处理单元620，用于根据第一发送窗口和该第二反馈消息确定第二发送窗口，该第一发送窗口包含该第一下行数据的序列号，在该第二反馈消息指示成功接收该第一下行数据的情况下，该第二发送窗口包含未向该终端设备发送的下行数据的序列号。
示例性地，该第一下行数据在该第二协议层的序列号、该第一下行数据在该第二协议层的超帧号、承载该第一下行数据的无线承载的标识、承载该第一下行数据的逻辑信道的标识。
可选地，处理单元620，具体用于该第二网络设备根据该第二反馈消息确定该第一发送窗口的前L个序列号对应的数据已经被该终端设备成功接收，该第二发送窗口的起始序列号等于第一发送窗口的第L+1个数据对应的序列号，L为正整数。
可选地，该第二反馈消息用于指示该终端设备成功接收该第二协议层的序列号连续的N个数据，该N个数据包括该第一下行数据，N为正整数，L＝N。
示例性地，该第二协议层为分组数据汇聚层。
可选地，收发单元610，还用于接收来自该第一网络设备的第一请求消息，该第一请求消息用于请求获取该终端设备的上下文，该第一请求消息包括用于指示小数据包传输的指示信息；收发单元610，还用于向该第一网络设备发送第一响应消息，该第一响应消息包括用于指示不执行锚点重定位的指示信息。
可选地，收发单元610，还用于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小数据包传输过程中避免数据丢失；收发单元610，还用于发送第四下行数据，该第四下行数据为小数据；收发单元610，还用于接收第一状态报告，该第一状态报告包括用于指示该终端设备未成功接收该第四下行数据的指示信息；收发单元610，还用于向第一网络设备发送该第四下行数据。
可选地，收发单元610，具体用于向该终端设备发送该第四下行数据；所收发单元610，具体用于接收来自该终端设备的该第一状态报告。
可选地，收发单元610，还用于接收来自该第一网络设备的第二请求消息，该第二请求消息用于请求获取该终端设备的上下文，该第二请求消息包括用于指示小数据包传输的指示信息；收发单元610，还用于向该第二网络设备发送第二响应消息，该第二响应消息包括用于指示执行锚点重定位的指示信息。
可选地，收发单元610，具体用于向第三网络设备发送该第四下行数据；收发单元610，具体用于接收来自该第三网络设备的该第一状态报告。
可选地，收发单元610，还用于向第三网络设备发送第四请求消息，该第四请求消息用于请求该第四下行数据的状态报告。
可选地，收发单元610，还用于接收来自该第一网络设备的第三请求消息，该第三请求消息用于请求获取该终端设备的上下文，该第三请求消息包括用于指示小数据包传输的指示信息；收发单元610，还用于向该第一网络设备发送第三响应消息，该第三响应消息包括用于指示不执行锚点重定位的指示信息。
可选地，该方法还包括：收发单元610，还用于向该终端设备发送无线资源控制释放 消息，该无线资源控制释放消息包括Y，Y为小数据包传输过程中小区重选的次数，Y为正整数。
另一种可能的实现方式，收发单元610，用于向终端设备发送第二指示信息，该第二指示信息用于指示小数据包传输过程中避免数据丢失；收发单元610，还用于接收来自该终端设备的第四上行数据，该第四上行数据为小数据；收发单元610，还用于向该终端设备发送第三状态报告，该第三状态报告包括以下指示信息中的至少一项：用于指示成功接收第一上行数据的指示信息，用于指示未成功接收第二上行数据的指示信息，该第四上行数据包括该第一上行数据和该第二上行数据；收发单元610，还用于向第一网络设备发送该第一上行数据。
可选地，收发单元610，还用于接收来自该第二网络设备的第二请求消息，该第二请求消息用于请求获取该终端设备的上下文，该第二请求消息包括用于指示小数据包传输的指示信息；收发单元610，还用于向该第二网络设备发送第二响应消息，该第二响应消息用于指示第二网络设备决定执行锚点重定位。
应理解，各单元执行上述相应步骤的具体过程在上述各方法实施例中已经详细说明，为了简洁，在此不再赘述。
还应理解，这里的装置600以功能单元的形式体现。这里的术语“单元”可以指应用特有集成电路(application specific integrated circuit，ASIC)、电子电路、用于执行一个或多个软件或固件程序的处理器(例如共享处理器、专有处理器或组处理器等)和存储器、合并逻辑电路和/或其它支持所描述的功能的合适组件。在一个可选例子中，本领域技术人员可以理解，装置600可以具体为上述实施例中的终端设备，可以用于执行上述各方法实施例中与终端设备对应的各个流程和/或步骤，或者，装置600可以具体为上述实施例中的第一网络设备或第二网络设备，可以用于执行上述各方法实施例中与第一网络设备或第二网络设备对应的各个流程和/或步骤，为避免重复，在此不再赘述。
上述各个方案的装置600具有实现上述方法中终端设备所执行的相应步骤的功能，或者，上述各个方案的装置600具有实现上述方法中第一网络设备或第二网络设备所执行的相应步骤的功能。所述功能可以通过硬件实现，也可以通过硬件执行相应的软件实现。所述硬件或软件包括一个或多个与上述功能相对应的模块；例如收发单元可以由收发机替代(例如，收发单元中的发送单元可以由发送机替代，收发单元中的接收单元可以由接收机替代)，其它单元，如处理单元等可以由处理器替代，分别执行各个方法实施例中的收发操作以及相关的处理操作。
此外，上述收发单元610还可以是收发电路(例如可以包括接收电路和发送电路)，处理单元可以是处理电路。
需要指出的是，图12中的装置可以是前述实施例中的网元或设备，也可以是芯片或者芯片系统，例如：片上系统(system on chip，SoC)。其中，收发单元可以是输入输出电路、通信接口；处理单元为该芯片上集成的处理器或者微处理器或者集成电路。在此不做限定。
图13是本申请实施例提供的另一种数据传输的装置700的示意图。该装置700包括处理器710，处理器710与存储器720耦合，存储器720用于存储计算机程序或指令和/或数据，处理器710用于执行存储器720存储的计算机程序或指令，或读取存储器720存 储的数据，以执行上文各方法实施例中的方法。
可选地，处理器710为一个或多个。
可选地，存储器720为一个或多个。
可选地，该存储器720与该处理器710集成在一起，或者分离设置。
可选地，如图13所示，该装置700还包括收发器1030，收发器1030用于信号的接收和/或发送。例如，处理器710用于控制收发器1030进行信号的接收和/或发送。
作为一种方案，该装置700用于实现上文各个方法实施例中由终端设备执行的操作。
例如，处理器710用于执行存储器720存储的计算机程序或指令，以实现上文各个方法实施例中终端设备的相关操作。例如，图5或图6所示实施例中的终端设备执行的方法。
作为一种方案，该装置700用于实现上文各个方法实施例中由第一网络设备或第二网络设备执行的操作。
例如，处理器710用于执行存储器720存储的计算机程序或指令，以实现上文各个方法实施例中网络设备的相关操作。例如，图5或图6所示实施例中的网络设备执行的方法。
应理解，本申请实施例中提及的处理器可以是中央处理单元(central processing unit，CPU)，还可以是其他通用处理器、数字信号处理器(digital signal processor，DSP)、专用集成电路(application specific integrated circuit，ASIC)、现成可编程门阵列(field programmable gate array，FPGA)或者其他可编程逻辑器件、分立门或者晶体管逻辑器件、分立硬件组件等。通用处理器可以是微处理器或者该处理器也可以是任何常规的处理器等。
还应理解，本申请实施例中提及的存储器可以是易失性存储器和/或非易失性存储器。其中，非易失性存储器可以是只读存储器(read-only memory，ROM)、可编程只读存储器(programmable ROM，PROM)、可擦除可编程只读存储器(erasable PROM，EPROM)、电可擦除可编程只读存储器(electrically EPROM，EEPROM)或闪存。易失性存储器可以是随机存取存储器(random access memory，RAM)。例如，RAM可以用作外部高速缓存。作为示例而非限定，RAM包括如下多种形式：静态随机存取存储器(static RAM，SRAM)、动态随机存取存储器(dynamic RAM，DRAM)、同步动态随机存取存储器(synchronous DRAM，SDRAM)、双倍数据速率同步动态随机存取存储器(double data rate SDRAM，DDR SDRAM)、增强型同步动态随机存取存储器(enhanced SDRAM，ESDRAM)、同步连接动态随机存取存储器(synchlink DRAM，SLDRAM)和直接内存总线随机存取存储器(direct rambus RAM，DR RAM)。
需要说明的是，当处理器为通用处理器、DSP、ASIC、FPGA或者其他可编程逻辑器件、分立门或者晶体管逻辑器件、分立硬件组件时，存储器(存储模块)可以集成在处理器中。
还需要说明的是，本文描述的存储器旨在包括但不限于这些和任意其它适合类型的存储器。
图14是本申请实施例提供的芯片系统800的示意图。该芯片系统800(或者也可以称为处理系统)包括逻辑电路810以及输入/输出接口(input/output interface)820。
其中，逻辑电路810可以为芯片系统800中的处理电路。逻辑电路810可以耦合连接存储单元，调用存储单元中的指令，使得芯片系统800可以实现本申请各实施例的方法和功能。输入/输出接口820，可以为芯片系统800中的输入输出电路，将芯片系统800处理 好的信息输出，或将待处理的数据或信令信息输入芯片系统800进行处理。
具体地，例如，若终端设备安装了该芯片系统800，逻辑电路810与输入/输出接口820耦合，逻辑电路810可通过输入/输出接口820向网络设备发现消息，该消息可以为逻辑电路810根据生成的；或者输入/输出接口820可将来自网络设备的第一信息输入至逻辑电路810进行处理。又如，若网络设备安装了该芯片系统800，逻辑电路810与输入/输出接口820耦合，逻辑电路810可通过输入/输出接口820向终端设备发送第一信息，该第一信息可以为逻辑电路810生成的；或者输入/输出接口820可将来自终端设备的消息输入至逻辑电路810进行处理。
作为一种方案，该芯片系统800用于实现上文各个方法实施例中由终端设备执行的操作。
例如，逻辑电路810用于实现上文方法实施例中由终端设备执行的处理相关的操作，如，图2或图3或图4所示实施例中的终端设备执行的处理相关的操作；输入/输出接口820用于实现上文方法实施例中由终端设备执行的发送和/或接收相关的操作，如，图2或图3或图4所示实施例中的终端设备执行的发送和/或接收相关的操作。
作为另一种方案，该芯片系统800用于实现上文各个方法实施例中由网络设备执行的操作。
例如，逻辑电路810用于实现上文方法实施例中由网络设备执行的处理相关的操作，如，图2或图3或图4所示实施例中的网络设备执行的处理相关的操作；输入/输出接口820用于实现上文方法实施例中由网络设备执行的发送和/或接收相关的操作，如，图2或图3或图4所示实施例中的网络设备执行的发送和/或接收相关的操作。
本申请实施例还提供一种计算机可读存储介质，其上存储有用于实现上述各方法实施例中由终端设备或网络设备执行的方法的计算机指令。
例如，该计算机程序被计算机执行时，使得该计算机可以实现上述方法各实施例中由终端设备或网络设备执行的方法。
本申请实施例还提供一种计算机程序产品，包含指令，该指令被计算机执行时以实现上述各方法实施例中由终端设备或网络设备执行的方法。
本申请实施例还提供一种通信系统，该通信系统包括上文各实施例中的终端设备和网络设备。例如，该系统包含图2或图3或图4所示实施例中的终端设备和网络设备。
上述提供的任一种装置中相关内容的解释及有益效果均可参考上文提供的对应的方法实施例，此处不再赘述。
在本申请所提供的几个实施例中，应该理解到，所揭露的装置和方法，可以通过其它的方式实现。例如，以上所描述的装置实施例仅是示意性的，例如，所述单元的划分，仅仅为一种逻辑功能划分，实际实现时可以有另外的划分方式，例如多个单元或组件可以结合或者可以集成到另一个系统，或一些特征可以忽略，或不执行。此外，所显示或讨论的相互之间的耦合或直接耦合或通信连接可以是通过一些接口，装置或单元的间接耦合或通信连接，可以是电性，机械或其它的形式。
在上述实施例中，可以全部或部分地通过软件、硬件、固件或者其任意组合来实现。当使用软件实现时，可以全部或部分地以计算机程序产品的形式实现。所述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所述计算机程序指令时，全部或部 分地产生按照本申请实施例所述的流程或功能。所述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。例如，所述计算机可以是个人计算机，服务器，或者网络设备等。所述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个计算机可读存储介质传输，例如，所述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(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。所述计算机可读存储介质可以是计算机能够存取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。所述可用介质可以是磁性介质(例如，软盘、硬盘、磁带)、光介质(例如，DVD)、或者半导体介质(例如固态硬盘(solid state disk，SSD)等。例如，前述的可用介质包括但不限于：U盘、移动硬盘、只读存储器(read-only memory，ROM)、随机存取存储器(random access memory，RAM)、磁碟或者光盘等各种可以存储程序代码的介质。
以上所述，仅为本申请的具体实施方式，但本申请的保护范围并不局限于此，任何熟悉本技术领域的技术人员在本申请揭露的技术范围内，可轻易想到变化或替换，都应涵盖在本申请的保护范围之内。因此，本申请的保护范围应以所述权利要求的保护范围为准。

Claims (69)

  1. 一种数据传输的方法，其特征在于，包括：
    第一网络设备接收来自第二网络设备的第一下行数据，所述第一下行数据为小数据；
    所述第一网络设备向终端设备发送所述第一下行数据；
    所述第一网络设备接收来自所述终端设备的第一反馈消息，所述第一反馈消息用于指示成功或未成功接收所述第一下行数据，所述一反馈消息对应第一协议层；
    所述第一网络设备根据所述第一反馈消息向所述第二网络设备发送第二反馈消息，所述第一反馈消息用于指示成功接收所述第一下行数据的情况下，所述第二反馈消息用于指示所述终端设备成功接收所述第一下行数据，所述第二反馈消息对应第二协议层。
  2. 根据权利要求1所述的方法，其特征在于，所述第一反馈消息包括以下至少一项：所述第一下行数据在所述第一协议层的序列号、承载所述第一下行数据的无线承载的标识、承载所述第一下行数据的逻辑信道的标识，所述第二反馈消息包括以下至少一项：所述第一下行数据在所述第二协议层的序列号、所述第一下行数据在所述第一协议层的序列号、承载所述第一下行数据的无线承载的标识、承载所述第一下行数据的逻辑信道的标识。
  3. 根据权利要求1或2所述的方法，其特征在于，所述方法还包括：
    所述第一网络设备根据所述第一反馈消息启动定时器。
  4. 根据权利要求3所述的方法，其特征在于，所述第一网络设备根据所述第一反馈消息向所述第二网络设备发送第二反馈消息，包括：
    所述定时器超时的情况下，所述第一网络设备根据所述第一反馈消息向所述第二网络设备发送第二反馈消息。
  5. 根据权利要求1至4中任一项所述的方法，其特征在于，所述第一网络设备根据所述第一反馈消息向所述第二网络设备发送第二反馈消息，包括：
    所述第一网络设备根据所述第一反馈消息确定终端设备成功接收所述第一协议层的M个数据，M为正整数；
    当所述M个数据中，第二协议层的序列号连续的数据的个数大于或等于N时，所述第一网络设备向所述第二网络设备发送第二反馈消息，所述第二反馈消息用于指示所述终端设备成功接收所述第二协议层的N个数据，所述N个数据包括所述第一下行数据，所述N为正整数。
  6. 根据权利要求1至5中任一项所述的方法，其特征在于，所述第一协议层为无线链路控制层，所述第二协议层为分组数据汇聚层。
  7. 根据权利要求1至6中任一项所述的方法，其特征在于，所述方法还包括：
    所述第一网络设备向所述第二网络设备发送第一请求消息，所述第一请求消息用于请求获取所述终端设备的上下文，所述第一请求消息包括用于指示小数据包传输的指示信息；
    所述第一网络设备接收来自所述第二网络设备的第一响应消息，所述第一响应消息包括用于指示不执行锚点重定位的指示信息。
  8. 根据权利要求1至7中任一项所述的方法，其特征在于，所述方法还包括：
    所述第一网络设备向所述终端设备发送第一指示信息，所述第一指示信息用于指示所 述第一网络设备支持在小数据包传输过程中避免数据丢失；
    所述第一网络设备接收来自第二网络设备的第四下行数据，所述第四下行数据为所述终端设备未成功接收的数据，所述第四下行数据为小数据；
    所述第一网络设备向所述终端设备发送所述第四下行数据。
  9. 根据权利要求8所述的方法，其特征在于，所述方法还包括：
    所述第一网络设备向所述第二网络设备发送第二请求消息，所述第二请求消息用于请求获取所述终端设备的上下文，所述第二请求消息包括用于指示小数据包传输的指示信息；
    所述第一网络设备接收来自所述第二网络设备的第二响应消息，所述第二响应消息包括用于指示执行锚点重定位的指示信息。
  10. 根据权利要求8所述的方法，其特征在于，所述方法还包括：
    所述第一网络设备向所述第二网络设备发送第三请求消息，所述第三请求消息用于请求获取所述终端设备的上下文，所述第三请求消息包括用于指示小数据包传输的指示信息；
    所述第一网络设备接收来自所述第二网络设备的第三响应消息，所述第三响应消息包括用于指示不执行锚点重定位的指示信息。
  11. 根据权利要求1至10中任一项所述的方法，其特征在于，所述方法还包括：
    所述第一网络设备向所述终端设备发送无线资源控制释放消息，所述无线资源控制释放消息包括Y，Y为小数据包传输过程中小区重选的次数，Y为正整数。
  12. 一种数据传输的方法，其特征在于，包括：
    第二网络设备向第一网络设备发送第一下行数据，所述第一下行数据为小数据，所述第一网络设备用于将所述第一下行数据发送给终端设备；
    所述第二网络设备接收来自所述第一网络设备的第二反馈消息，所述第二反馈消息用于指示终端设备成功接收或未成功接收所述第一下行数据，所述第二反馈消息与第二协议层对应；
    所述第二网络设备根据第一发送窗口和所述第二反馈消息确定第二发送窗口，所述第一发送窗口包含所述第一下行数据的序列号，在所述第二反馈消息指示成功接收所述第一下行数据的情况下，所述第二发送窗口包含未向所述终端设备发送的下行数据的序列号。
  13. 根据权利要求12所述的方法，其特征在于，所述第二反馈消息包括以下至少一项：所述第一下行数据在所述第二协议层的序列号、所述第一下行数据在所述第二协议层的超帧号、承载所述第一下行数据的无线承载的标识、承载所述第一下行数据的逻辑信道的标识。
  14. 根据权利要求12或13所述的方法，其特征在于，所述方法还包括：
    所述第二网络设备根据所述第二反馈消息确定所述第一发送窗口的前L个序列号对应的数据已经被所述终端设备成功接收，所述第二发送窗口的起始序列号等于第一发送窗口的第L+1个数据对应的序列号，L为正整数。
  15. 根据权利要求12或13所述的方法，其特征在于，所述第二反馈消息用于指示所述终端设备成功接收所述第二协议层的序列号连续的N个数据，所述N个数据包括所述第一下行数据，N为正整数，L＝N。
  16. 根据权利要求12至14中任一项所述的方法，其特征在于，所述第二协议层为分组数据汇聚层。
  17. 根据权利要求12至16中任一项所述的方法，其特征在于，所述方法还包括：
    所述第二网络设备接收来自所述第一网络设备的第一请求消息，所述第一请求消息用于请求获取所述终端设备的上下文，所述第一请求消息包括用于指示小数据包传输的指示信息；
    所述第二网络设备向所述第一网络设备发送第一响应消息，所述第一响应消息包括用于指示不执行锚点重定位的指示信息。
  18. 根据权利要求12至17中任一项所述的方法，其特征在于，包括：
    所述第二网络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小数据包传输过程中避免数据丢失；
    所述第二网络设备发送第四下行数据，所述第四下行数据为小数据；
    所述第二网络设备接收第一状态报告，所述第一状态报告包括用于指示所述终端设备未成功接收所述第四下行数据的指示信息；
    所述第二网络设备向第一网络设备发送所述第四下行数据。
  19. 根据权利要求18所述的方法，其特征在于，
    所述第二网络设备发送第四下行数据，包括：所述第二网络设备向所述终端设备发送所述第四下行数据；
    所述第二网络设备接收第一状态报告，包括：所述第二网络设备接收来自所述终端设备的所述第一状态报告。
  20. 根据权利要求19所述的方法，其特征在于，所述方法还包括：
    所述第二网络设备接收来自所述第一网络设备的第二请求消息，所述第二请求消息用于请求获取所述终端设备的上下文，所述第二请求消息包括用于指示小数据包传输的指示信息；
    所述第二网络设备向所述第二网络设备发送第二响应消息，所述第二响应消息包括用于指示执行锚点重定位的指示信息。
  21. 根据权利要求18所述的方法，其特征在于，
    所述第二网络设备发送第四下行数据，包括：所述第二网络设备向第三网络设备发送所述第四下行数据；
    所述第二网络设备接收第一状态报告，包括：所述第二网络设备接收来自所述第三网络设备的所述第一状态报告。
  22. 根据权利要求21所述的方法，其特征在于，所述方法还包括：所述第二网络设备向第三网络设备发送第四请求消息，所述第四请求消息用于请求所述第四下行数据的状态报告。
  23. 根据权利要求21或22所述的方法，其特征在于，所述方法还包括：
    所述第二网络设备接收来自所述第一网络设备的第三请求消息，所述第三请求消息用于请求获取所述终端设备的上下文，所述第三请求消息包括用于指示小数据包传输的指示信息；
    所述第二网络设备向所述第一网络设备发送第三响应消息，所述第三响应消息包括用于指示不执行锚点重定位的指示信息。
  24. 根据权利要求12至23中任一项所述的方法，其特征在于，所述方法还包括：
    所述第一网络设备向所述终端设备发送无线资源控制释放消息，所述无线资源控制释放消息包括Y，Y为小数据包传输过程中小区重选的次数，Y为正整数。
  25. 一种数据传输的方法，其特征在于，包括：
    终端设备接收来自第二网络设备的第二指示信息，所述第二指示信息用于指示小数据包传输过程中避免数据丢失；
    所述终端设备接收第四下行数据，所述第四下行数据为小数据；
    所述终端设备发送用于指示未成功接收所述第四下行数据的指示信息；
    所述终端设备接收来自第一网络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网络设备支持在小数据包传输过程中避免数据丢失；
    所述终端设备接收来自所述第一网络设备的第四下行数据。
  26. 根据权利要求25所述的方法，其特征在于，
    所述终端设备接收第四下行数据，包括：所述终端设备接收来自所述第二网络设备的所述第四下行数据；
    所述终端设备发送用于指示未成功接收所述第四下行数据的指示信息，包括：所述终端设备向所述第二网络设备发送第一状态报告，所述第一状态报告包括所述指示信息。
  27. 根据权利要求25所述的方法，其特征在于，
    所述终端设备接收第四下行数据，包括：所述终端设备接收来自所述第三网络设备的所述第四下行数据；
    所述终端设备发送用于指示未成功接收所述第四下行数据的指示信息，包括：所述终端设备向第三网络设备发送第二状态报告，所述第二状态报告包括所述指示信息。
  28. 根据权利要25至27中任一项所述的方法，其特征在于，所述方法还包括：
    所述终端设备接收来自所述网络设备的无线资源控制释放消息，所述无线资源控制释放消息包括Y，Y为小数据包传输过程中小区重选的次数，Y为正整数；
    所述终端设备发起小数据包传输过程；
    所述终端设备记录小区重选的次数；
    在所述终端设备记录的小区重选的次数≥Y的情况下，所述终端设备切换至无线资源控制空闲态，或者，所述终端设备向网络设备发送非小数据包传输的恢复请求消息。
  29. 一种数据传输的方法，其特征在于，包括：
    第三网络设备接收来自第二网络设备的第四下行数据，所述第四下行数据为小数据；
    所述第三网络设备向终端设备发送所述第四下行数据；
    所述第三网络设备接收来自所述终端设备的第二状态报告，所述第二状态报告包括用于指示所述终端设备未成功接收所述第四下行数据的指示信息；
    所述第三网络设备根据所述第二状态报告向所述第二网络设备发送第一状态报告，所述第一状态报告包括用于指示所述终端设备未成功接收所述第四下行数据的指示信息。
  30. 根据权利要求29所述的方法，其特征在于，所述方法还包括：
    所述第三网络设备接收来自所述第二网络设备的第四请求消息，所述第四请求消息用于请求所述第四下行数据的状态报告。
  31. 根据权利要求29或30所述的方法，其特征在于，所述方法还包括：
    所述第三网络设备释放与所述终端设备的链路，停止与所述终端设备通信。
  32. 一种数据传输装置，其特征在于，包括：
    接收模块，用于接收来自第二网络设备的第一下行数据，所述第一下行数据为小数据；
    发送模块，用于向终端设备发送所述第一下行数据；
    所述接收模块还用于接收来自所述终端设备的第一反馈消息，所述第一反馈消息用于指示成功或未成功接收所述第一下行数据，所述一反馈消息对应第一协议层；
    所述发送模块还用于根据所述第一反馈消息向所述第二网络设备发送第二反馈消息，所述第一反馈消息用于指示成功接收所述第一下行数据的情况下，所述第二反馈消息用于指示所述终端设备成功接收所述第一下行数据，所述第二反馈消息对应第二协议层。
  33. 根据权利要求32所述的装置，其特征在于，所述第一反馈消息包括以下至少一项：所述第一下行数据在所述第一协议层的序列号、承载所述第一下行数据的无线承载的标识、承载所述第一下行数据的逻辑信道的标识，所述第二反馈消息包括以下至少一项：所述第一下行数据在所述第二协议层的序列号、所述第一下行数据在所述第一协议层的序列号、承载所述第一下行数据的无线承载的标识、承载所述第一下行数据的逻辑信道的标识。
  34. 根据权利要求32或33所述的装置，其特征在于，所述装置还包括处理模块，用于根据所述第一反馈消息启动定时器。
  35. 根据权利要求34所述的装置，其特征在于，所述发送设备用于在所述定时器超时的情况下，根据所述第一反馈消息向所述第二网络设备发送第二反馈消息。
  36. 根据权利要求32至35中任一项所述的装置，其特征在于，
    所述处理模块还用于所述第一反馈消息确定终端设备成功接收所述第一协议层的M个数据，M为正整数；
    当所述M个数据中，第二协议层的序列号连续的数据的个数大于或等于N时，所述发送模块用于向所述第二网络设备发送第二反馈消息，所述第二反馈消息用于指示所述终端设备成功接收所述第二协议层的N个数据，所述N个数据包括所述第一下行数据，所述N为正整数。
  37. 根据权利要求32至36中任一项所述的装置，其特征在于，所述第一协议层为无线链路控制层，所述第二协议层为分组数据汇聚层。
  38. 根据权利要求32至37中任一项所述的装置，其特征在于，
    所述发送模块还用于向所述第二网络设备发送第一请求消息，所述第一请求消息用于请求获取所述终端设备的上下文，所述第一请求消息包括用于指示小数据包传输的指示信息；
    所述接收模块还用于接收来自所述第二网络设备的第一响应消息，所述第一响应消息包括用于指示不执行锚点重定位的指示信息。
  39. 根据权利要求32至38中任一项所述的装置，其特征在于，
    所述发送模块还用于向所述终端设备发送第一指示信息，所述第一指示信息用于指示所述第一网络设备支持在小数据包传输过程中避免数据丢失；
    所述接收模块还用于接收来自第二网络设备的第四下行数据，所述第四下行数据为所述终端设备未成功接收的数据，所述第四下行数据为小数据；
    所述发送模块还用于向所述终端设备发送所述第四下行数据。
  40. 根据权利要求39所述的装置，其特征在于，
    所述发送模块还用于向所述第二网络设备发送第二请求消息，所述第二请求消息用于请求获取所述终端设备的上下文，所述第二请求消息包括用于指示小数据包传输的指示信息；
    所述接收模块还用于接收来自所述第二网络设备的第二响应消息，所述第二响应消息包括用于指示执行锚点重定位的指示信息。
  41. 根据权利要求40所述的装置，其特征在于，
    所述发送模块还用于向所述第二网络设备发送第三请求消息，所述第三请求消息用于请求获取所述终端设备的上下文，所述第三请求消息包括用于指示小数据包传输的指示信息；
    所述接收模块还用于接收来自所述第二网络设备的第三响应消息，所述第三响应消息包括用于指示不执行锚点重定位的指示信息。
  42. 根据权利要求32至41中任一项所述的装置，其特征在于，
    所述发送模块还用于向所述终端设备发送无线资源控制释放消息，所述无线资源控制释放消息包括Y，Y为小数据包传输过程中小区重选的次数，Y为正整数。
  43. 一种数据传输装置，其特征在于，包括：
    发送模块，用于向第一网络设备发送第一下行数据，所述第一下行数据为小数据，所述第一网络设备用于将所述第一下行数据发送给终端设备；
    接收模块，用于接收来自所述第一网络设备的第二反馈消息，所述第二反馈消息用于指示终端设备成功接收或未成功接收所述第一下行数据，所述第二反馈消息与第二协议层对应；
    处理模块，用于根据第一发送窗口和所述第二反馈消息确定第二发送窗口，所述第一发送窗口包含所述第一下行数据的序列号，在所述第二反馈消息指示成功接收所述第一下行数据的情况下，所述第二发送窗口包含未向所述终端设备发送的下行数据的序列号。
  44. 根据权利要求43所述的装置，其特征在于，所述第二反馈消息包括以下至少一项：所述第一下行数据在所述第二协议层的序列号、所述第一下行数据在所述第二协议层的超帧号、承载所述第一下行数据的无线承载的标识、承载所述第一下行数据的逻辑信道的标识。
  45. 根据权利要求43或44所述的装置，其特征在于，
    所述处理模块还用于根据所述第二反馈消息确定所述第一发送窗口的前L个序列号对应的数据已经被所述终端设备成功接收，所述第二发送窗口的起始序列号等于第一发送窗口的第L+1个数据对应的序列号，L为正整数。
  46. 根据权利要求43或44所述的装置，其特征在于，所述第二反馈消息用于指示所述终端设备成功接收所述第二协议层的序列号连续的N个数据，所述N个数据包括所述第一下行数据，N为正整数，L＝N。
  47. 根据权利要求43至45中任一项所述的装置，其特征在于，所述第二协议层为分组数据汇聚层。
  48. 根据权利要求43至47中任一项所述的装置，其特征在于：
    所述接收模块还用于接收来自所述第一网络设备的第一请求消息，所述第一请求消息 用于请求获取所述终端设备的上下文，所述第一请求消息包括用于指示小数据包传输的指示信息；
    所述发送模块还用于向所述第一网络设备发送第一响应消息，所述第一响应消息包括用于指示不执行锚点重定位的指示信息。
  49. 根据权利要求43至48中任一项所述的装置，其特征在于，包括：
    所述发送模块还用于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小数据包传输过程中避免数据丢失；
    所述发送模块还用于发送第四下行数据，所述第四下行数据为小数据；
    所述接收模块还用于接收第一状态报告，所述第一状态报告包括用于指示所述终端设备未成功接收所述第四下行数据的指示信息；
    所述发送模块还用于向第一网络设备发送所述第四下行数据。
  50. 根据权利要求49所述的装置，其特征在于，
    所述发送模块还用于发送第四下行数据，包括：所述第二网络设备向所述终端设备发送所述第四下行数据；
    所述接收模块还用于接收第一状态报告，包括：所述第二网络设备接收来自所述终端设备的所述第一状态报告。
  51. 根据权利要求50所述的装置，其特征在于，
    所述接收模块还用于接收来自所述第一网络设备的第二请求消息，所述第二请求消息用于请求获取所述终端设备的上下文，所述第二请求消息包括用于指示小数据包传输的指示信息；
    所述发送模块还用于向所述第二网络设备发送第二响应消息，所述第二响应消息包括用于指示执行锚点重定位的指示信息。
  52. 根据权利要求49所述的装置，其特征在于，
    所述发送模块还用于发送第四下行数据，包括：所述第二网络设备向第三网络设备发送所述第四下行数据；
    所述接收模块还用于接收第一状态报告，包括：所述第二网络设备接收来自所述第三网络设备的所述第一状态报告。
  53. 根据权利要求52所述的装置，其特征在于，所述发送模块还用于向第三网络设备发送第四请求消息，所述第四请求消息用于请求所述第四下行数据的状态报告。
  54. 根据权利要求52或53所述的装置，其特征在于，
    所述接收模块还用于接收来自所述第一网络设备的第三请求消息，所述第三请求消息用于请求获取所述终端设备的上下文，所述第三请求消息包括用于指示小数据包传输的指示信息；
    所述发送模块还用于向所述第一网络设备发送第三响应消息，所述第三响应消息包括用于指示不执行锚点重定位的指示信息。
  55. 根据权利要求43至54中任一项所述的装置，其特征在于，
    所述发送模块还用于向所述终端设备发送无线资源控制释放消息，所述无线资源控制释放消息包括Y，Y为小数据包传输过程中小区重选的次数，Y为正整数。
  56. 一种数据传输装置，其特征在于，包括：
    接收模块，用于接收来自第二网络设备的第二指示信息，所述第二指示信息用于指示小数据包传输过程中避免数据丢失；
    所述接收模块还用于接收第四下行数据，所述第四下行数据为小数据；
    发送模块，用于发送用于指示未成功接收所述第四下行数据的指示信息；
    所述接收模块还用于接收来自第一网络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网络设备支持在小数据包传输过程中避免数据丢失；
    所述接收模块还用于接收来自所述第一网络设备的第四下行数据。
  57. 根据权利要求56所述的装置，其特征在于，
    所述接收模块还用于接收来自所述第二网络设备的所述第四下行数据；
    所述发送模块还用于向所述第二网络设备发送第一状态报告，所述第一状态报告包括所述指示信息。
  58. 根据权利要求56所述的装置，其特征在于，
    所述接收模块还用于接收来自所述第三网络设备的所述第四下行数据；
    所述发送模块还用于向第三网络设备发送第二状态报告，所述第二状态报告包括所述指示信息。
  59. 根据权利要56至58中任一项所述的装置，其特征在于，
    所述接收模块还用于接收来自所述网络设备的无线资源控制释放消息，所述无线资源控制释放消息包括Y，Y为小数据包传输过程中小区重选的次数，Y为正整数；
    所述处理模块还用于发起小数据包传输过程；
    所述处理模块还用于记录小区重选的次数；
    在所述处理模块记录的小区重选的次数≥Y的情况下，所述处理模块还用于切换至无线资源控制空闲态，或者，所述发送模块还用于向网络设备发送非小数据包传输的恢复请求消息。
  60. 一种数据传输装置，其特征在于，包括：
    接收模块，用于接收来自第二网络设备的第四下行数据，所述第四下行数据为小数据；
    发送模块，用于向终端设备发送所述第四下行数据；
    所述接收模块还用于接收来自所述终端设备的第二状态报告，所述第二状态报告包括用于指示所述终端设备未成功接收所述第四下行数据的指示信息；
    所述发送模块还用于根据所述第二状态报告向所述第二网络设备发送第一状态报告，所述第一状态报告包括用于指示所述终端设备未成功接收所述第四下行数据的指示信息。
  61. 根据权利要求60所述的装置，其特征在于，
    所述接收模块还用于接收来自所述第二网络设备的第四请求消息，所述第四请求消息用于请求所述第四下行数据的状态报告。
  62. 根据权利要求60或61所述的装置，其特征在于，所述装置还包括处理模块，用于释放与所述终端设备的链路，停止与所述终端设备通信。
  63. 一种数据传输装置，其特征在于，包括：
    处理器，用于执行存储器中存储的计算机程序，以使得所述装置执行如权利要求1至11中任一项所述的方法，或者以使得所述装置执行如权利要求12至24中任一项所述的方法，或者以使得所述装置执行如权利要求25至28中任一项所述的方法，或者以使得所 述装置执行如权利要求29至31中任一项所述的方法。
  64. 根据权利要求63所述的装置，所述装置还包括所述存储器。
  65. 一种计算机可读存储介质，其特征在于，所述计算机可读存储介质上存储有计算机程序，当所述计算机程序在计算机上运行时，使得所述计算机执行如权利要求1至11中任意一项所述的方法，或者以使得所述计算机执行如权利要求12至2中任一项所述的方法，或者以使得所述计算机执行如权利要求25至28中任一项所述的方法，或者以使得所述计算机执行如权利要求29至31中任一项所述的方法。
  66. 一种计算机程序产品，其特征在于，所述计算机程序产品包括用于执行如权利要求1至11中任一项所述的方法的指令，或者，所述计算机程序产品包括用于执行如权利要求12至24中任一项所述的方法的指令或者，所述计算机程序产品包括用于执行如权利要求25至28中任一项所述的方法的指令，所述计算机程序产品包括用于执行如权利要求29至31中任一项所述的方法的指令。
  67. 一种通信系统，其特征在于，包括第一网络设备和第二网络设备，
    其中，所述终端设备用于执行如权利要求1至11中任一项所述的方法，所述网络设备用于执行如权利要求12至24中任一项所述的方法。
  68. 一种通信系统，其特征在于，包括如下通信装置的一项或多项：如权利要求32至42中任一项所述的通信装置，如权利要求43至55中任一项所述的通信装置，如权利要求56至59中任一项所述的通信装置，以及如权利要求60至62中任一项所述的通信装置。
  69. 一种通信装置，其特征在于，所述装置用于执行如权利要求1至31中任一项所述的方法。
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