WO2021062746A1

WO2021062746A1 - Data transmission method and apparatus

Info

Publication number: WO2021062746A1
Application number: PCT/CN2019/109664
Authority: WO
Inventors: 严乐; 曾清海; 唐珣; 耿婷婷
Original assignee: 华为技术有限公司
Priority date: 2019-09-30
Filing date: 2019-09-30
Publication date: 2021-04-08

Abstract

The present application provides a data transmission method and apparatus. The method comprises: a terminal device receives first instruction information, the first instruction information being used for instructing the terminal device to convert from the physical uplink shared channel (PUSCH) transmission with a source network device to the PUSCH transmission with a target network device; and then the terminal device converts, according to the first instruction information, from the PUSCH transmission with the source network device to the PUSCH transmission with the target network device. Therefore, embodiments of the present application clearly define the moment when the UL data transmission of the terminal device is switched from the source network device to the target network device, which can guarantee that the interruption delay of the UL data transmission is reduced during terminal device switching, and further facilitate achieving UL data transmission of 0 ms interruption.

Description

Method and device for data transmission

Technical field

This application relates to the field of communications, and more specifically, to methods and devices for data transmission in the field of communications.

Background technique

In a mobile communication system, as the terminal device moves, the network device switches the terminal device from the source cell to the target cell for data transmission through a handover process. In the traditional handover process, after the source network device sends a handover message to the terminal device, the data transmission between the terminal device and the source network device will be interrupted. Until the terminal device is successfully switched to the target network device, the terminal device can communicate with the target network device. data transmission. Therefore, during the handover process, during the period from the source network device sending the handover message to the terminal device to the successful handover of the terminal device to the target network device, there is no data transmission on the air interface, and there is an interruption delay.

In a handover enhancement solution, in order to reduce the interruption delay, after the source network device sends a handover message to the terminal device, data transmission can be maintained between the terminal device and the source network device. For example, for downlink data transmission, the terminal device maintains data transmission with the source network device until the terminal device can receive data from the target network device, or until the terminal device disconnects the RRC connection/data transmission with the source network device. In this handover enhancement solution, the terminal device can perform downlink data transmission with the source network device and the target network device at the same time during the period from receiving the handover message to releasing the connection with the source network device. However, the terminal device may not be able to communicate with the source network device at the same time. The source network device and the target network device perform uplink transmission. Therefore, how the terminal device performs uplink data transmission is a problem that needs to be solved urgently.

Summary of the invention

This application provides a method and device for data transmission, which is helpful for realizing 0ms uplink data transmission.

In the first aspect, a data transmission method is provided, which is executed by a terminal device or a component (for example, a chip or a circuit, etc.) configurable in the terminal device. In the following, the method is executed by a terminal device as an example for description.

In this method, the terminal device receives first indication information, and the first indication information is used to instruct the terminal device to switch from physical uplink shared channel PUSCH transmission with the source network device to PUSCH transmission with the target network device. The terminal device maintains PUSCH transmission with the source network device before receiving the first instruction information, and the terminal device starts PUSCH transmission with the target network device after receiving the first instruction information. Then, the terminal device converts the PUSCH transmission with the source network device to the PUSCH transmission with the target network device according to the first instruction information.

Therefore, in this embodiment of the present application, when the terminal device receives the first indication information, the UL data transmission of the terminal device is switched from the source network device to the target network device. That is to say, the embodiment of the present application clearly defines the moment when the UL data transmission of the terminal device is switched from the source network device to the target network device, which can ensure that the terminal device reduces the interruption delay of UL data transmission during the switching process. Further, there is Helps realize UL data transmission with 0ms interruption.

In the embodiment of the present application, the first indication information may be sent to the terminal device by the source network device or the target network device, which is not limited in the embodiment of the present application.

With reference to the first aspect, in some implementations of the first aspect, the terminal device may also receive second indication information, which is used to indicate that the terminal device needs to transmit to the target network device after converting to PUSCH transmission with the target network device. The minimum data convergence protocol PDCP serial number SN of the uplink data packet sent by the target network device. In this way, the terminal device can determine the PDCP SN of the uplink data packet that needs to be sent to the target network device according to the second indication information.

As an example, the minimum PDCP SN may be the PDCP SN of the first uplink data packet sent to the target network device after the terminal device is converted to perform PUSCH transmission with the target network device.

In some possible embodiments, the second indication information may also be used to instruct the terminal device to switch from physical uplink shared channel PUSCH transmission with the source network device to PUSCH transmission with the target network device. At this time, the minimum data convergence protocol PDCP sequence number SN of the uplink data packet that needs to be sent to the target network device after the terminal device is converted to perform PUSCH transmission with the target network device can be instructed to implicitly indicate that the terminal device is transferred from The physical uplink shared channel PUSCH transmission with the source network device is converted to the PUSCH transmission with the target network device.

In combination with the first aspect, some implementations of the first aspect further include:

The terminal device receives uplink grant (UL grant) information, where the uplink grant information is allocated to the terminal device by the target network device and used for PUSCH transmission between the terminal device and the target network device.

In this way, the terminal device can obtain the UL grant according to the UL grant information, and use the UL grant to perform uplink data transmission with the target network device. As an example, the UL grant information may include PUSCH resource information, MCS information, etc., which is not limited in the embodiment of the present application.

In some possible embodiments, the first indication information may also be UL uplink grant information, which is not limited in the embodiment of the present application.

Therefore, in the embodiment of the present application, the terminal device is instructed by the network device to indicate the time when the PUSCH data transmission of the terminal device is converted from the source network device to the target network device, which is beneficial to realize that the terminal device starts to communicate with the target network after determining the above-mentioned conversion time. The device performs uplink data transmission to ensure that the terminal device reduces the UL data transmission interruption delay during the handover process, and further, helps to achieve 0ms UL data transmission interruption. Furthermore, by instructing the terminal device to transmit the minimum PDCP SN or UL grant information of the uplink data packet to the target network device after converting to PUSCH transmission with the target network device, the UL data transmission interruption can be further reduced. Extension.

With reference to the first aspect, in some implementation manners of the first aspect, before receiving the first indication information, the terminal device sends an RRC reconfiguration complete message to the target network device, or receives an RAR message sent by the target network device.

When the source network device sends the first indication information to the terminal device, the target network device may send the indication information to the source network device after receiving the RRC reconfiguration complete message sent by the terminal device or sending the RAR message to the terminal device. To indicate that the terminal device has successfully connected/switched to the target network device. After receiving the instruction information, the source network device may send the first instruction information to the terminal device.

In the second aspect, a data transmission method is provided, which is executed by a component (for example, a chip or a circuit, etc.) of the network device that can be configured in the network device. The following describes the method executed by a network device as an example.

In this method, the network device may obtain first indication information, which is used to instruct the terminal device to switch from physical uplink shared channel PUSCH transmission with the source network device to PUSCH transmission with the target network device. Then, the network device sends the first instruction information to the terminal device, where the terminal device maintains PUSCH transmission with the source network device before receiving the first instruction information, and starts to communicate with the target network device after receiving the first instruction information PUSCH transmission.

In the embodiment of the present application, the source network device or the target network device may send the first indication information to the terminal device, which is not limited in the embodiment of the present application.

With reference to the second aspect, in some implementations of the second aspect, the network device may also determine second indication information, which is used to indicate that the terminal device needs to transmit to the target network device after converting to PUSCH transmission with the target network device. The minimum data convergence protocol PDCP serial number SN of the uplink data packet sent by the target network device. Then, the network device sends the second indication information to the terminal device. In this way, the terminal device can determine the PDCP SN of the uplink data packet that needs to be sent to the target network device according to the second indication information.

With reference to the second aspect, in some implementations of the second aspect, the network device may also send uplink authorization information to the terminal device. The uplink authorization information is allocated by the target network device to the terminal device and used for the terminal device to communicate with the target network device. PUSCH transmission.

In some optional embodiments of this application, the target network device may indicate to the terminal device the time when the terminal device’s PUSCH data transmission is converted from the source network device to the target network device, and the terminal device is converting to PUSCH transmission with the target network device. After that, the minimum PDCP SN of the uplink data packet that needs to be sent to the target network device is helpful for the terminal device to start the uplink data transmission with the target network device after determining the above conversion time, so as to ensure that the terminal device reduces the number of data during the handover process. The UL data transmission interruption time delay, further, helps to achieve 0ms UL data transmission interruption. At this time, the source network device does not need to forward the first indication information, so system signaling overhead can be saved.

In some optional embodiments of this application, the source network device may indicate to the terminal device the time when the terminal device’s PUSCH data transmission is converted from the source network device to the target network device, and the terminal device is converting to PUSCH transmission with the target network device. After that, the minimum PDCP SN of the uplink data packet that needs to be sent to the target network device is helpful for the terminal device to start the uplink data transmission with the target network device after determining the above conversion time, so as to ensure that the terminal device reduces the number of data during the handover process. The UL data transmission interruption time delay, further, helps to realize the UL data transmission with 0ms interruption. At this time, optionally, the source network device may receive the first indication information from the target network device and/or the minimum PDCP SN of the uplink data packet that the terminal device needs to send to the target network device. At this time, the source network device forwards the first indication information and/or the minimum PDCP SN of the uplink data packet that the terminal device needs to send to the target network device, which can be more flexible to indicate the above conversion time and/or terminal device needs to the terminal device The minimum PDCP SN of the uplink data packet sent to the target network device.

When the method in the second aspect and some implementations of the second aspect is executed by the target network device or a chip in the target network, the target network device receives an RRC reconfiguration complete message from the terminal device or sends an RAR to the terminal device. After the message, third indication information may also be sent to the source network device, where the third indication information is used to indicate to the source network device that the terminal device has successfully switched to the target network device. In this way, the source network device can determine, according to the third indication information, that the terminal device has successfully accessed/switched to the target network device.

Optionally, the aforementioned target network device may also receive a PDCP status report from the source network device, where the PDCP status report is used to obtain the minimum PDCP SN of the uplink data packet of the uplink data that needs to be sent to the target network device.

When the methods in the second aspect and some implementations of the second aspect are executed by the source network device or a chip in the source network device, the source network device may also receive third instruction information sent by the target network device, and the third instruction information is used Instructing the source network device that the terminal device successfully switches to the target network device. In this way, the source network device can determine, according to the third indication information, that the terminal device has successfully accessed/switched to the target network device.

Optionally, the aforementioned source network device may also receive uplink authorization information sent by the target network device, where the uplink authorization information is allocated by the target network device to the terminal device and used for PUSCH transmission between the terminal device and the target network device.

With reference to the first aspect or the second aspect, in some implementation manners of the first or second aspect, the second indication information includes the PDCP SN of the first uplink data packet sent by the terminal device to the target network device. In this way, the network device can directly indicate to the terminal device the PDCP SN of the first uplink data packet sent by the terminal device to the target network device.

With reference to the first aspect or the second aspect, in some implementations of the first aspect or the second aspect, the second indication information may include a UL PDCP status report, and the UL PDCP status report is used to obtain the foregoing information from the target The minimum PDCP SN of the uplink data packet sent by the network device. In this way, the network device can indicate to the terminal device the PDCP SN of the first uplink data packet sent by the terminal device to the target network device through the UL PDCP status report.

With reference to the first aspect or the second aspect, in some implementations of the first or second aspect, the second indication information may include the PDCP SN of the last uplink data packet sent by the terminal device to the source network device, then at this time The PDCP SN of the first uplink data packet sent by the terminal device to the target network device is the first PDCP SN after the PDCP SN included in the second indication information.

With reference to the first aspect or the second aspect, in some implementation manners of the first aspect or the second aspect, the PDCP SN is bearer granular. That is, each bearer may have its own corresponding PDCP SN value, and the above PDCP SN corresponding to each bearer may be the same or different, which is not limited in the embodiment of the present application.

Optionally, in addition to the PDCP SN, the foregoing second indication information may also include the RB ID corresponding to the PDCP SN. In some optional embodiments, the above-mentioned second indication information may not include the RB ID, and the association relationship between the PDCP SN and the RB contained in the second indication information is agreed by the agreement.

With reference to the first aspect or the second aspect, in some implementations of the first aspect or the second aspect, the second indication information may be carried with granularity. In other words, each bearer may have corresponding second indication information.

In this way, the terminal device can determine the minimum PDCP SN of the uplink data packet that the terminal device needs to send to the target network device on the bearer according to the bearer used for sending the second indication information. In other words, the terminal device can determine the minimum PDCP SN of the uplink data packet sent to the target network device when the terminal device and the target network device transmit the uplink data packet corresponding to the bearer according to the bearer used for sending the second indication information.

With reference to the first aspect or the second aspect, in some implementations of the first aspect or the second aspect, at least one of the first indication information, the second indication information, and the uplink authorization information may be included in the same message It is sent to the terminal device, or sent to the terminal device in separate messages, which is not limited in the embodiment of the present application. As an example, the foregoing message may be an RRC message, or a layer 2 message, or a physical layer message, which is not limited in the embodiment of the present application. Among them, the layer 2 message may be, for example, PDCP control (control) PDU, MAC CE, and so on. The physical layer message may be, for example, DCI.

In a third aspect, a data transmission method is provided, which is executed by a component (for example, a chip or a circuit, etc.) of the terminal device that can be configured in the terminal device. In the following, the method executed by the terminal device is described as an example.

In this method, the terminal device receives fourth indication information, which is used to indicate at least one PDCP sequence number SN corresponding to at least one packet data convergence protocol PDCP protocol data unit PDU, and the at least one PDCP The PDU is a PDCP PDU that the source network device has not successfully sent to the terminal device. Then, the terminal device receives the at least one PDCP PDU from the target network device, and uses the parameters corresponding to the source network device to process the at least one PDCP PDU, wherein the at least one PDCP PDU received from the target network device is A PDCP PDU is a PDCP PDU from the source network device.

Therefore, in this embodiment of the application, the source network device forwards at least one PDCP PDU(s) that is not successfully sent to the terminal device to the target network device, instead of forwarding the unsuccessful PDCP SDU(s) to the target network device, so that the target network The device does not need to use its own corresponding header compression context, key, etc. to process the DL data that has not been successfully sent by the source network device, which can help the terminal device to correctly receive the DL data from the target network device.

In a fourth aspect, a data transmission method is provided, which is executed by a source network device or a component (for example, a chip or a circuit, etc.) configurable in the source network device. The following describes the method executed by the source network device as an example.

In this method, the source network device sends at least one PDCP PDU to the target network device, and the at least one PDCP PDU is a PDCP PDU that the source network device has not successfully sent to the terminal device. Then, the source network device sends fourth indication information to the terminal device or the target network device, where the fourth indication information is used to indicate at least one PDCP sequence number SN corresponding to the at least one PDCP PDU one-to-one .

Therefore, in this embodiment of the application, the source network device forwards at least one PDCP PDU(s) that is not successfully sent to the terminal device to the target network device, instead of forwarding the unsuccessful PDCP SDU(s) to the target network device, so that the target network The device does not need to use its own corresponding header compression context, key, etc. to process these DL data packets that have not been successfully sent by the source network device. At the same time, the network device sends instructions to the terminal device to indicate that these DL data packets have not been successfully sent by the source network device. The PDCP SN corresponding to the successfully sent DL data packets can thereby help the terminal device to correctly receive and process these DL data packets from the target network device.

In a fifth aspect, a data transmission method is provided, which is executed by a target network device or a component (for example, a chip or a circuit, etc.) configurable in the target network device. The following describes the method executed by the target network device as an example.

In this method, the target network device receives at least one PDCP PDU from the source network device, and the at least one PDCP PDU is a PDCP PDU that the source network device has not successfully sent to the terminal device. Then, the target network device receives fourth indication information from the source network device, where the fourth indication information is used to indicate the at least one PDCP sequence number SN corresponding to the at least one PDCP PDU one-to-one. Then, the target network device sends the fourth indication information and the at least one PDCP PDU to the terminal device.

With reference to the third aspect, the fourth aspect, or the fifth aspect, in some implementation manners of the third aspect, the fourth aspect, or the fifth aspect, the at least one PDCP SN has a bearer granularity.

In a sixth aspect, a data transmission method is provided, which is executed by a terminal device or a component (for example, a chip or a circuit, etc.) configurable in the terminal device. In the following, the method is executed by a terminal device as an example for description.

In this method, the terminal device obtains sixth indication information, where the sixth indication information is used to indicate that the third PDCP SN corresponding to the third PDCP PDU received by the terminal device from the target network device and the source network device are the first 3. The mapping relationship between the PDCP SN allocated by the PDCP SDU, and the second PDCP SN corresponding to the second PDCP PDU received from the target network device and the PDCP SN allocated by the source network device for the second PDCP SDU Mapping relationship, wherein the third PDCP PDU is generated after the target network device uses the parameters corresponding to the target network device to process the third PDCP SDU from the source network device, and the third The PDCP SN is allocated by the target network device, and the second PDCP PDU is generated after the target network device uses the parameters corresponding to the target network device to process the second PDCP SDU from the source network device And the second PDCP SN is allocated by the target network device, and the third PDCP SDU is before the target network device receives the second PDCP SDU, the source network device sends to the target network device In the first PDCP SDU sent, the target network device has not yet used the parameters corresponding to the target network device to process the PDCP SDU, and the second PDCP SDU is not successfully received by the terminal device from the source network device PDCP SDU.

Then, the terminal device receives the third PDCP PDU and the second PDCP PDU from the target network device, and uses the parameters corresponding to the target network device to process the third PDCP according to the sixth indication information PDU and the second PDCP PDU.

Therefore, in the embodiment of the present application, the target network device sends the unsuccessfully sent PDCP SDU(s) forwarded by the source network device to the terminal device after special processing. For example, the target network device can allocate virtual PDCP SDU(s) forwarded by the source network device that are not successfully sent to the terminal device, and PDCP SDU(s) in the buffer area of the target network device that have not been sent to the terminal device. PDCP SN', and the corresponding processing method (for example, the actual PDCP SN and the virtual PDCP SN', that is, the mapping relationship between the actual PDCP SN and the virtual PDCP SN'; or, for example, the first offset value, the first Two offset value) Notify the terminal device so that the terminal device can correctly process the PDCP PDUs received from the target network device, so that the terminal device can correctly receive DL data.

With reference to the sixth aspect, in some possible implementations of the sixth aspect, the terminal device may obtain the third PDCP SN and the third PDCP SN corresponding to the third PDCP PDU received by the terminal device from the target network device according to the sixth indication information. The mapping relationship between the PDCP SN allocated by the source network device for the third PDCP SDU, and the second PDCP SN corresponding to the second PDCP PDU received from the target network device and the source network device are the second PDCP The mapping relationship between PDCP and SN allocated by SDU. Then, according to the PDCP SN allocated by the source network device for the second PDCP SDU and the second PDCP SN, the parameters corresponding to the target network device are used to process the second PDCP PDU. Then, according to the PDCP SN allocated by the source network device to the third PDCP SDU and the third PDCP SN, use the parameters corresponding to the target network device to process the third PDCP PDU.

In a seventh aspect, a data transmission method is provided, which is executed by a target network device or a component (for example, a chip or a circuit, etc.) configurable in the target network device. The following describes the method executed by the target network device as an example.

In this method, the target network device receives the first PDCP SDU from the source network device, and the PDCP SN allocated by the source network device to the first PDCP SDU.

The target network device receives a second PDCP SDU from the source network device, and the PDCP SN allocated by the source network device to the second PDCP SDU, and the second PDCP SDU is that the terminal device does not receive the PDCP SDU from the source network The PDCP SDU successfully received by the device.

The target network device sends a third PDCP PDU and a second PDCP PDU to the terminal device, where the third PDCP PDU means that the target network device uses the parameters corresponding to the target network device to perform the third PDCP SDU After processing, the second PDCP PDU is generated after the target network device uses the parameters corresponding to the target network device to process the second PDCP SDU, and the third PDCP SDU is generated in the target network device. Before the network device receives the second PDCP SDU, the target network device in the first PDCP SDU has not yet processed the PDCP SDU using the parameters corresponding to the target network device.

The target network device sends sixth indication information, where the sixth indication information is used to indicate the relationship between the third PDCP SN corresponding to the third PDCP PDU and the PDCP SN allocated by the source network device for the third PDCP SDU The mapping relationship, and the mapping relationship between the second PDCP SN corresponding to the second PDCP PDU and the PDCP SN allocated by the source network device for the second PDCP SDU, where the second PDCP SN and the third PDCP SN are The PDCP SN is allocated by the target network device.

In some possible embodiments, the target network device may send the sixth instruction information to the terminal device, or send the first instruction information to the source network device, which is not limited in the embodiment of the present application.

In an eighth aspect, a data transmission method is provided, which is executed by a source network device or a component (for example, a chip or a circuit, etc.) configurable in the source network device. The following describes the method executed by the source network device as an example.

In this method, the source network device sends the first PDCP SDU to the target network device, and the PDCP SN allocated by the source network device to the first PDCP SDU.

The source network device sends a second PDCP SDU to the target network device, and the PDCP SN allocated by the source network device to the second PDCP SDU, and the second PDCP SDU is that the terminal device is not from the source network The PDCP SDU successfully received by the device.

The source network device receives sixth indication information from the target network device, where the sixth indication information is used to indicate that the third PDCP SN corresponding to the third PDCP PDU received by the terminal device from the target network device is related to the third PDCP SN corresponding to the third PDCP PDU received from the target network device. The mapping relationship between the PDCP SN allocated by the source network device for the third PDCP SDU, and the second PDCP SN corresponding to the second PDCP PDU received from the target network device and the source network device allocated for the second PDCP SDU The mapping relationship between the PDCP SNs, where the third PDCP PDU is generated after the target network device uses the parameters corresponding to the target network device to process the third PDCP SDU from the source network device and The third PDCP SN is allocated by the target network device, and the second PDCP PDU is used by the target network device to process the second PDCP SDU from the source network device using the parameters corresponding to the target network device The second PDCP SN is generated later and the second PDCP SN is allocated by the target network device, and the third PDCP SDU is before the target network device receives the second PDCP SDU, all of the first PDCP SDU The target network device has not yet used the PDCP SDU processed by the parameters corresponding to the target network device.

The source network device sends the sixth indication information to the terminal device.

With reference to the sixth or seventh or eighth aspects, in some implementations of the sixth or seventh or eighth aspects, the sixth indication information includes a first offset value and a second offset value, so The first offset value is the offset of the third PDCP SN relative to the PDCP SN allocated by the source network device for the third PDCP SDU, and the second offset value is the offset relative to the second PDCP SN. The offset of the PDCP SN allocated by the source network device for the second PDCP SDU; or

The sixth indication information includes at least one PDCP SN in the third PDCP SN and at least one of the PDCP SN allocated by the source network device corresponding to the at least one PDCP SN in the third PDCP SN PDCP SN. Optionally, the sixth indication information further includes at least one PDCP SN in the second PDCP SN and the source network device corresponding to at least one PDCP SN in the second PDCP SN. At least one PDCP SN in the allocated PDCP SN.

With reference to the sixth aspect, the seventh aspect, or the eighth aspect, in some implementation manners of the sixth aspect, the seventh aspect, or the eighth aspect, the first offset value is determined according to the number of the second PDCP SDUs Yes, the second offset value is determined according to the first offset value and the number of fourth PDCP SDUs, where the fourth PDCP SDU is received by the target network device. Previously, the target network device in the first PDCP SDU has already used the parameters corresponding to the target network device to perform the PDCP SDU corresponding to the PDCP layer processing.

In the ninth aspect, the embodiments of the present application provide a communication device for executing the method in any one of the first to eighth aspects or any possible implementation of any one of the aspects. Specifically, the device includes A module for executing the method in any one of the above-mentioned first aspect to the eighth aspect or any possible implementation manner of any one of the aspects.

In a tenth aspect, an embodiment of the present application provides a communication device, including a processor and a transceiver. Optionally, memory may also be included. Wherein, the memory is used to store instructions, the processor is used to execute instructions stored in the memory, and when the processor executes the instructions stored in the memory, the execution causes the processor to execute any one of the first aspect to the eighth aspect Aspect or any possible implementation of any aspect.

In an eleventh aspect, an embodiment of the present application provides a computer-readable medium for storing a computer program, and the computer program includes a computer program for executing any one of the first to eighth aspects or any possible implementation of any one of the aspects. The instruction of the method in the way.

In the twelfth aspect, the embodiments of the present application also provide a computer program product containing instructions, when the computer program product is run on a computer, the computer is caused to execute any or any one of the first to eighth aspects Any possible implementation of the method.

In a thirteenth aspect, a chip is provided, including a processor and a communication interface. The processor is used to call and execute instructions from the communication interface. When the processor executes the instructions, the first aspect to the The method in any one of the eighth aspect or any possible implementation of any one of the aspects.

Optionally, the chip may further include a memory in which instructions are stored, and the processor is configured to execute instructions stored in the memory or instructions derived from other sources. When the instruction is executed, the processor is used to implement any one of the foregoing first to eighth aspects or the method in any possible implementation manner of any one of the aspects.

In a fourteenth aspect, a communication system is provided. The communication system includes a device capable of implementing the methods and various possible designs of the above-mentioned first aspect, and the above-mentioned methods and various possible designs of the above-mentioned second aspect are implemented. The function of the device.

In a fifteenth aspect, a communication system is provided. The communication system includes a device capable of implementing the methods and various possible designs of the foregoing third aspect, and the foregoing has the methods and various possible designs that implement the foregoing fourth aspect. The device with the functions of the above, and the above-mentioned device with the functions of the various methods and various possible designs of the above-mentioned fifth aspect.

In a sixteenth aspect, a communication system is provided. The communication system includes a device capable of implementing the methods and various possible designs of the above-mentioned sixth aspect, and the above-mentioned methods and various possible designs are provided for implementing the above-mentioned seventh aspect. The device with the functions of the above, and the above-mentioned device with the functions of the various methods and various possible designs of the above-mentioned eighth aspect.

Description of the drawings

Fig. 1 shows a schematic diagram of a network architecture to which an embodiment of the present application is applied.

Fig. 2 shows a schematic diagram of another network architecture to which an embodiment of the present application is applied.

Fig. 3 shows another schematic diagram of a network architecture to which an embodiment of the present application is applied.

Fig. 4 shows a schematic flowchart of data transmission at a PDCP layer.

FIG. 5 shows a schematic flowchart of a data transmission method provided by an embodiment of the present application.

FIG. 6 shows a schematic flowchart of another data transmission method provided by an embodiment of the present application.

FIG. 7 shows a schematic flowchart of another data transmission method provided by an embodiment of the present application.

Figure 8 shows a schematic diagram of the user plane protocol stack architecture on the network device side corresponding to downlink data transmission

FIG. 9 shows a schematic flowchart of another data transmission method provided in an embodiment of the present application.

FIG. 10 shows a schematic flowchart of another data transmission method provided by an embodiment of the present application.

FIG. 11 shows a schematic flowchart of another data transmission method provided by an embodiment of the present application.

FIG. 12 shows a schematic flowchart of another data transmission method provided by an embodiment of the present application.

FIG. 13 shows a schematic diagram of a wireless communication apparatus provided by an embodiment of the present application.

Fig. 14 shows a schematic structural diagram of a terminal device provided by the present application.

FIG. 15 shows a schematic structural diagram of a network device provided by an embodiment of the present application.

Detailed ways

The technical solution in this application will be described below in conjunction with the accompanying drawings.

The technical solutions of the embodiments of this application can be applied to various communication systems, such as: long term evolution (LTE) system, LTE frequency division duplex (FDD) system, LTE time division duplex (time division duplex) , TDD), universal mobile telecommunication system (UMTS), worldwide interoperability for microwave access (WiMAX) communication system, the future 5th generation (5G) system or new wireless ( new radio, NR), and subsequent evolution of communication systems.

The terminal equipment in the embodiments of this application may also be referred to as: user equipment (UE), mobile station (MS), mobile terminal (MT), access terminal, user unit, user station, Mobile station, mobile station, remote station, remote terminal, mobile device, user terminal, terminal, wireless communication device, user agent or user device, etc.

The terminal device may be a device that provides voice/data connectivity to the user, for example, a handheld device with a wireless connection function, a vehicle-mounted device, and so on. At present, some examples of terminals are: mobile phones (mobile phones), tablet computers, notebook computers, handheld computers, mobile internet devices (MID), wearable devices, virtual reality (VR) devices, and augmented reality. (augmented reality, AR) equipment, wireless terminals in industrial control, wireless terminals in self-driving, wireless terminals in remote medical surgery, and smart grids Wireless terminals, wireless terminals in transportation safety, wireless terminals in smart cities, wireless terminals in smart homes, cellular phones, cordless phones, session initiation protocols , SIP) phone, wireless local loop (wireless local loop, WLL) station, personal digital assistant (personal digital assistant, PDA), handheld device with wireless communication function, computing device or other processing device connected to wireless modem, vehicle Devices, wearable devices, terminal devices in the future 5G network or terminal devices in the future evolved public land mobile network (PLMN), etc., which are not limited in the embodiment of the present application.

As an example and not a limitation, in the embodiments of the present application, wearable devices can also be referred to as wearable smart devices. It is a general term for using wearable technology to intelligently design daily wear and develop wearable devices, such as glasses, Gloves, watches, clothing and shoes, etc. A wearable device is a portable device that is directly worn on the body or integrated into the user's clothes or accessories. Wearable devices are not only a kind of hardware device, but also realize powerful functions through software support, data interaction, and cloud interaction. In a broad sense, wearable smart devices include full-featured, large-sized, complete or partial functions that can be achieved without relying on smart phones, such as smart watches or smart glasses, and only focus on a certain type of application function, and need to cooperate with other devices such as smart phones. Use, such as all kinds of smart bracelets and smart jewelry for physical sign monitoring.

In addition, in the embodiments of the present application, the terminal device may also be a terminal device in the Internet of Things (IoT) system. IoT is an important part of the development of information technology in the future. Its main technical feature is to pass items through communication technology. Connect with the network to realize the intelligent network of human-machine interconnection and interconnection of things.

In addition, the network device in the embodiment of the present application may be a device used to communicate with terminal devices. The network device may also be called an access device or a radio access network device, and may be an evolved NodeB in the LTE system. , ENB or eNodeB), it can also be a wireless controller in a cloud radio access network (cloud radio access network, CRAN) scenario, or the access device can be a relay station, an access point, a vehicle-mounted device, a wearable device, and the future The access equipment in the 5G network or the network equipment in the future evolved PLMN network can be the access point (AP) in the WLAN, or the gNB in the new radio (NR) system. The application examples are not limited.

In a network structure, a network device may include a centralized unit (CU) node, or a distributed unit (DU) node, or a RAN device including a CU node and a DU node, or a control plane CU node (CU). -CP node), user plane CU node (CU-UP node) and RAN equipment of DU node.

Fig. 1 shows a schematic diagram of a network architecture to which an embodiment of the present application is applied. As shown in Fig. 1, when the terminal device moves, it is possible to switch the serving cell according to the change of the signal strength of the cell. In FIG. 1, the source network device is the network device to which the serving cell where the terminal device is currently located, and the target network device is the network device to which the target cell to which the terminal device will be handed over belongs. In the embodiments of the present application, the source network device and the target network device may be base stations of the same radio access type (RAT), or may be base stations of different RATs.

Fig. 2 shows a schematic diagram of another network architecture to which an embodiment of the present application is applied. As shown in Figure 2, the communication between network equipment and terminal equipment follows a certain protocol layer structure. For example, the control plane protocol layer structure can include the radio resource control (RRC) layer, the packet data convergence protocol (PDCP) layer, the radio link control (RLC) layer, and the media interface. Access control (media access control, MAC) layer and physical layer and other protocol layer functions. The user plane protocol layer structure can include the functions of the PDCP layer, the RLC layer, the MAC layer, and the physical layer; in one implementation, the PDCP layer can also include the service data adaptation protocol (SDAP) Floor.

The functions of these protocol layers can be implemented by one node or multiple nodes; for example, in an evolution structure, the access device can include a centralized unit (CU) and a distributed unit (DU) , Multiple DUs can be centrally controlled by one CU.

As shown in Figure 2, CU and DU can be divided according to the protocol layer of the wireless network. For example, the functions of the PDCP layer and the above protocol layers are set in the CU, and the protocol layers below the PDCP, such as the RLC layer and MAC layer, are set in the DU. In other words, the CU has functions above the PDCP layer (including PDCP, SDAP, and RRC), and the DU has functions below the PDCP layer (including RLC, MAC, and PHY).

This type of protocol layer division is just an example, it can also be divided in other protocol layers, for example, in the RLC layer, the functions of the RLC layer and above protocol layers are set in the CU, and the functions of the protocol layers below the RLC layer are set in the DU; Or, in a certain protocol layer, for example, part of the functions of the RLC layer and the functions of the protocol layer above the RLC layer are set in the CU, and the remaining functions of the RLC layer and the functions of the protocol layer below the RLC layer are set in the DU. In addition, it can also be divided in other ways, for example, by time delay. The functions that need to meet the delay requirement for processing time are set in the DU, and the functions that do not need to meet the delay requirement are set in the CU.

Fig. 3 shows another schematic diagram of a network architecture to which an embodiment of the present application is applied. Compared with the architecture shown in Figure 2, the control plane (CP) and user plane (UP) of the CU can also be separated and divided into different entities for implementation, namely the control plane CU entity (CU-CP entity) and the user plane CU entity (CU-UP entity).

In the above network architecture, the signaling generated by the CU can be sent to the terminal device through the DU, or the signaling generated by the terminal device can be sent to the CU through the DU. The DU can directly pass the protocol layer encapsulation without analyzing the signaling and transparently transmit it to the terminal device or CU. If the following embodiments involve the transmission of such signaling between the DU and the terminal device, at this time, the sending or receiving of the signaling by the DU includes this scenario.

In the above embodiments, the CU is divided into network equipment on the RAN side of the access network. In addition, the CU may also be divided into network equipment on the CN side of the core network, which is not limited here.

The devices in the following embodiments of the present application may be located in terminal equipment or network equipment according to their realized functions. When the above CU-DU structure is adopted, the network device may be a CU node, or a DU node, or a RAN device including a CU node and a DU node.

Fig. 4 shows a schematic flow chart of data transmission by the PDCP layer. Among them, when performing uplink data transmission, the sending end may be a terminal device, and the receiving end may be a network device. When performing downlink data transmission, the sending end may be a network device, and the receiving end may be a terminal device.

During data transmission, for the PDCP layer of the sender (that is, send the PDCP entity, or send the PDCP protocol stack), the relevant parameters corresponding to the sender (such as the header compression context, integrity protection parameters, keys, etc. corresponding to the sender) can be used , Process the PDCP service data unit (service data unit, SDU). As an example, the PDCP layer of the sender may perform PDCP sequence number (sequence number, SN) allocation and header compression (header compression) to the PDCP SDU in the transmission buffer (transmission buffer). After header compression, integrity protection, ciphering, add PDCP header, routing/duplication, etc. are processed to generate PDCP protocol data unit, PDU).

The PDCP layer at the receiving end (that is, the receiving PDCP entity or the receiving PDCP protocol stack) can use related parameters (such as header decompression context, integrity verification parameters, keys, etc.) to process the received PDCP PDUs. As an example, the PDCP layer at the receiving end may remove the PDCP header (remove PDCP header) from the received PDCP PDU. After removing the PDCP header, perform deciphering, integrity verification, reordering and duplicate discarding in the reception buffer, and then perform header decompression ( header decomposition) and other processing to get PDCP SDUs.

It should be noted that the PDCP layer at the receiving end or the transmitting end has a bearing granularity. That is, for one or more bearers established (or existing) between the terminal device and the network device, each of the one or more bearers has its own corresponding PDCP layer. In other words, corresponding to any one of the one or more bearers, the terminal device and the network device respectively establish (or exist) a PDCP layer corresponding to any one of the bearers. In the embodiment of the present application, the bearer includes a data radio bearer (DRB) and/or a signaling radio bearer (SRB).

In the embodiment of the present application, when the terminal device is in the process of switching from the source network device to the target network device, it does not support the terminal device to simultaneously perform uplink (UL) data transmission with the source network device and the target network device. That is, at a certain moment in the handover process, the terminal device performs UL data transmission with one of the source network device or the target network device. In other words, there is a moment in the handover process. Before this moment, the terminal device performs UL data transmission with the source network device, and after this moment, the terminal device performs UL data transmission with the target network device.

As an example, UL data transmission may include at least one of the following: physical uplink shared channel (PUSCH) transmission, hybrid automatic repeat request (HARQ) acknowledgement/negative acknowledgement, ACK/NACK) feedback transmission, automatic repeat request (ARQ) ACK/NACK feedback transmission, channel status information (CSI) feedback transmission, robust header compression (ROHC) feedback Transmission, media access control (medium access control, MAC) control element (CE) transmission, physical uplink control channel (physical uplink control channel, PUCCH) transmission. The MAC CE may include, for example, a buffer status report (buffer status report, BSR), a power headroom report (power headroom report, PHR), and so on. Exemplarily, PUSCH transmission may include transmission of new data packets (such as new PDCP SDUs) and transmission of unacknowledged data packets (such as unacknowledged PDCP SDUs).

Therefore, the embodiment of the present application can also be described as that the UL data transmission is switched from the source network device to the target network device at the above moment. That is to say, the embodiment of the present application clearly defines the moment when the UL data transmission of the terminal device is switched from the source network device to the target network device, so as to ensure that the terminal device reduces the interruption delay of UL data transmission during the switching process. Helps realize UL data transmission with 0ms interruption.

The method and device for data transmission provided by this application will be described in detail below with reference to the accompanying drawings.

The technical solution of the present application can be applied to a wireless communication system, and communication devices in the wireless communication system may have a wireless communication connection relationship. One of the communication devices may be, for example, a source network device or a chip configured in the source network device, and the other of the communication devices may be, for example, a target access device or a chip configured in a target device. The other one of the communication devices may be a terminal device, or a chip configured in the terminal device, for example.

In the following, without loss of generality, first, a data transmission process of a terminal device is taken as an example to describe the embodiments of the present application in detail. It can be understood that any terminal device in the wireless communication system or the chip configured in the terminal device can perform data transmission based on the same method, and any network device in the wireless communication system or the chip configured in the network device can be Data transmission can be based on the same method. This application does not limit this.

For convenience, the following description will be given by taking "UL data transmission" as "PUSCH transmission" as an example, but the embodiments of the present application are not limited thereto. For example, the "PUSCH transmission" appearing below can also be replaced with any one or more of the above-mentioned "UL data transmission". For example, "PUSCH transmission" can be replaced with "HARQ ACK/NACK feedback transmission", or " "PUSCH transmission" can be replaced with "ARQ ACK/NACK feedback transmission", or "PUSCH transmission" can be replaced with "PUSCH transmission and HARQ ACK/NACK feedback transmission", etc., which is not limited in this embodiment. The data transmission solution provided in the embodiment of the present application is also applicable to other uplink data that the terminal device needs to send to the network device.

FIG. 5 is a schematic flowchart of a data transmission method 500 from the perspective of device interaction. As shown in FIG. 5, the data transmission method 500 may include steps 510 to 530.

510. The network device acquires first indication information, where the first indication information is used to instruct the terminal device to switch from performing physical uplink shared channel PUSCH transmission with the source network device to performing PUSCH transmission with the target network device.

That is, before receiving the first indication information, the terminal device maintains PUSCH transmission with the source network device, and after receiving the first indication information, starts PUSCH transmission with the target network device. As an example, after receiving the first indication information, the terminal device may stop PUSCH transmission with the source network device, and start PUSCH transmission with the target network device. Here, the PUSCH transmission between the terminal device and the network device may refer to the data transmission between the terminal device and the network device through the PUSCH.

As an example, the first indication information may be a binary value (such as a bit), or a Boolean value, or a certain cell, or other manifestations, which are not limited in the embodiment of the present application. For example, when the bit of the first indication information is "1", it may instruct the terminal device to switch from physical uplink shared channel PUSCH transmission with the source network device to PUSCH transmission with the target network device. For another example, when the first indication information is a Boolean value and the Boolean value is "true", it may indicate that the terminal device is converted from physical uplink shared channel PUSCH transmission with the source network device to PUSCH transmission with the target network device.

In the embodiment of the present application, the network device that executes the method 500 may be a source network device or a target network device, which is not limited in the embodiment of the present application.

It should be noted that as the terminal device moves, the network device may send a handover message to the terminal device to instruct the terminal device to change the serving base station. After receiving the handover message, the terminal device establishes an RRC connection with the target network device. After the establishment of RRC with the target network device is completed, the terminal device starts data transmission with the target network device. Specifically, the handover message may be an RRC reconfiguration message including a synchronization reconfiguration (ReconfigurationWithSync) cell, or the handover message may be an RRC connection reconfiguration message including a mobility control information (MobilityControlInfo) cell. Not limited.

In some possible implementations of the embodiments of the present application, after receiving the "handover message", the terminal device can still maintain the RRC connection/data transmission with the source network device. For example, the terminal device can continue to communicate with the source network device. PUSCH transmission and/or PDSCH transmission are carried out in between, until the network device (such as the source network device or the target network device) notifies the terminal device to release the RRC connection/data transmission with the source network device.

That is, for uplink transmission, the terminal device performs PUSCH transmission with the source network device before receiving the handover message, and after receiving the handover message, it can still maintain the PUSCH transmission with the source network device.

520. The network device sends the foregoing first indication information to the terminal device. Correspondingly, the terminal device receives the first indication information.

In some possible implementation manners, the first indication information may be that after the terminal device successfully accesses/switches to the target network device (for example, after the RRC establishment between the terminal device and the target network device is completed), the source network device or The target network device sent to the terminal device. As an example, after the target network device receives the RRC reconfiguration complete message sent by the terminal device, the target network device or the source network device may perform step 520, that is, the target network device or the source network device sends the first indication information to the terminal device.

In an example, after receiving the RRC reconfiguration complete message sent by the terminal device, the target network device may send indication information to the source network device to indicate that the terminal device has successfully accessed/switched to the target network device. After receiving the instruction information, the source network device may send the foregoing first instruction information to the terminal device. In some possible implementation manners, when the source network device obtains the first indication information, the source network device may receive the first indication information from the target network device.

530. The terminal device switches from performing PUSCH transmission with the source network device to performing PUSCH transmission with the target network device according to the first indication information.

That is, at the moment when the terminal device receives the first indication information, the UL data transmission of the terminal device is switched from the source network device to the target network device.

Optionally, after receiving the handover message, the terminal device may also receive the first indication information sent by the network device. After receiving the first indication information, the terminal device may start PUSCH transmission with the target network device, and the terminal device may maintain PUSCH transmission with the source network device before receiving the first indication information. That is, the terminal device maintains PUSCH transmission with the source network device until the first indication information is received, and after receiving the first indication information, the terminal device can perform PUSCH transmission with the target network device.

In some possible implementation manners, after receiving the first indication information, the terminal device may start PUSCH transmission with the target network device. Optionally, after receiving the first indication information, the terminal device may continue to maintain PUSCH transmission with the source network device. For example, if the terminal device supports the capability, the terminal device may continue to transmit the PUSCH after receiving the first indication information. Continue to maintain the PUSCH transmission with the source network device until the source network device has a radio link failure.

Therefore, in the embodiment of the present application, the network device sends the first instruction information to the terminal device to instruct the terminal device to switch from PUSCH transmission with the source network device to PUSCH transmission with the target network device, that is, when receiving the first instruction information The PUSCH transmission with the source network device was maintained before, and after receiving the first indication information, the PUSCH transmission with the target network device is started. The embodiment of the application can clearly define that the PUSCH data transmission of the terminal device is switched from the source network device to the target network device. The time of the network equipment is to ensure that the terminal equipment reduces the UL data transmission interruption time delay during the handover process, and further helps the terminal equipment to achieve 0ms data transmission interruption during the handover process.

Different from the foregoing implementation manner of sending the first indication information (by the target network device or the source network device) after the target network device receives the RRC reconfiguration complete message, in another possible implementation manner, the target network device may send the first indication information to After the terminal device sends a random access response (RAR) message, the source network device or the target network device sends the first indication information to the terminal device. In other words, the terminal device can receive the first indication information after receiving the RAR message sent by the target network device, and after receiving the first indication information, perform PUSCH transmission with the source network device into PUSCH transmission with the target network device. That is, the terminal device maintains PUSCH transmission with the source network device before receiving the first indication information, and performs PUSCH transmission with the target network device after receiving the first indication information.

Or, in another possible implementation manner, after the target network device sends a random access response (RAR) message and UL grant information to the terminal device, the source network device or the target network device sends the first network device to the terminal device. One instruction information. In other words, the terminal device may receive the first indication information after receiving the random access response RAR message sent by the target network device and the UL grant information allocated by the target network device, and after receiving the first indication information, the terminal device can communicate with the source The network device performs PUSCH transmission into PUSCH transmission with the target network device, that is, the terminal device maintains PUSCH transmission with the source network device before receiving the first instruction information, and after receiving the first instruction information, communicates with the target network device. The device performs PUSCH transmission.

Or, in another possible implementation manner, after the target network device sends the UL grant message to the terminal device, the source network device or the target network device may send the first indication information to the terminal device. In other words, the terminal device may receive the first indication information after receiving the UL grant information allocated by the target network device, and after receiving the first indication information, perform PUSCH transmission with the source network device into PUSCH transmission with the target network device. Transmission, that is, the terminal device maintains PUSCH transmission with the source network device before receiving the first indication information, and performs PUSCH transmission with the target network device after receiving the first indication information.

In some optional embodiments, when the source network device or the target network device does not send the first indication information, the terminal device may send the RRC reconfiguration complete message, and/or receive the RAR message, and/or receive the UL grant information, The PUSCH transmission with the source network device is converted to the PUSCH transmission with the target network device. That is, the terminal device maintains PUSCH transmission with the source network device before sending the RRC reconfiguration complete message, and/or receiving the RAR message, and/or receiving the UL grant information, and sends the RRC reconfiguration complete message, and/or Or after receiving the RAR message, and/or receiving the UL grant information, perform PUSCH transmission with the target network device.

In some possible implementation manners, the network device may also determine the second indication information, which is used to indicate the uplink data packet that the terminal device needs to send to the target network device after converting to PUSCH transmission with the target network device The smallest data convergence protocol PDCP serial number SN. After determining the second indication information, the network device may send the second indication information to the terminal device. Here, the network device may be a source network device or a target network device. Correspondingly, the terminal device receives the second indication information. Here, the uplink data packet may be a PUSCH data packet. For example, the PUSCH data packet may include new data packets (such as new PDCP SDUs) and unacknowledged data packets (such as unacknowledged PDCP SDUs). In this way, the terminal device can determine the PDCP SN of the uplink data packet that needs to be sent to the target network device according to the second indication information.

In a possible situation, the second indication information includes the PDCP SN of the first uplink data packet sent by the terminal device to the target network device. In other words, the network device can directly indicate to the terminal device the PDCP SN of the first uplink data packet sent by the terminal device to the target network device.

As an example, before sending the foregoing first indication information to the terminal device, the source network device has successfully received an uplink data packet with a PDCP SN of 0-50 from the terminal device. At this time, the second indication information may be 51, which indicates that the PDCP SN of the first uplink data packet that the terminal device will send to the target network device is 51. In other words, among the PDCP SNs corresponding to the uplink data packets sent by the terminal device to the target network device, the smallest PDCP SN is 51.

As another example, before sending the above-mentioned first indication information to the terminal device, the source network device has successfully received from the terminal device an uplink data packet with a PDCP SN of 0-45 and a PDCP SN of 48, 50. In one implementation, the second indication information may be 46, indicating that the PDCP SN of the first uplink data packet that the terminal device will send to the target network device is 46, and the second indication information can also indicate that the PDCP SN is 46. The upstream data packet was not successfully received by the source network device. That is, the terminal device needs to retransmit the uplink data packet whose PDCP SN is 46. For example, the terminal device sends the uplink data packet whose PDCP SN is 46 to the target network device. Optionally, the terminal device also sends uplink data packets with PDCP SN of 47-50 respectively, and subsequent uplink data packets to the target network device. Or, in another implementation manner, the second indication information may be 46, 47, and 49, indicating that the PDCP SN of the first three uplink data packets that the terminal device will send to the target network device are 46, 47, and 49 respectively, and at the same time The second indication information can also indicate that the uplink data packets whose PDCP SNs are 46, 47, and 49 are not successfully received by the source network device. In other words, the terminal device needs to retransmit the uplink data packets whose PDCP SN is 46, 47, and 49. For example, the terminal device sends the uplink data packets whose PDCP SN is 46, PDCP SN is 47, and PDCP SN is 49. Target network device. After that, the terminal device sends the uplink data packet with the PDCP SN of 51 and later to the target network device.

In another possible situation, the second indication information may include a UL PDCP status report, and the UL PDCP status report is used to obtain the minimum PDCP SN of the uplink data packet that needs to be sent to the target network device. Here, the UL PDCP status report is generated by the source network device according to the reception status of the uplink data packet received from the terminal device, and is used to indicate the reception status of the uplink data packet sent by the terminal device to the source network device, where the reception status includes successful reception Or the reception fails.

It should be noted that the above "received successfully" refers to the network device successfully receiving the uplink data packet sent by the terminal device, and it can also be described as the terminal device successfully sending the uplink data packet to the network device, and the two indicate the same or similar meaning. In addition, the above-mentioned "reception failure" refers to that the network device did not successfully receive the uplink data packet sent by the terminal device. It can also be described as the terminal device failed to send the uplink data packet to the network device, and the two have the same or similar meaning.

As an example, before sending the above-mentioned first indication information to the terminal device, the source network device generates/acquires the PDCP status report of the uplink data packet whose PDCP SN is 0-50 sent by the terminal device. When the PDCP status report is used to indicate that the uplink data packets with PDCP SN 0-50 sent by the terminal device to the source network device are successfully received, the minimum PDCP SN of the uplink data packet that the terminal device needs to send to the target network device is 51. When the PDCP status report is used to indicate that the PDCP SN sent by the terminal device to the source network device is 0-47, and the uplink data packet with PDCP SN of 49 is successfully received, and the uplink data packet with PDCP of 48 and PDCP SN of 50 is not successfully received At this time, the minimum PDCP SN of the uplink data packet that the terminal device needs to send to the target network device is 48. In one implementation, the terminal device needs to retransmit uplink data packets with PDCP SN of 48 and 50 respectively. For example, the terminal device sends uplink data packets with PDCP SN of 48 and PDCP SN of 50 to the target network device. Or, in another implementation, the terminal device needs to retransmit the uplink data packets with PDCP SN of 48, 49, and 50 respectively. For example, the terminal device sets PDCP SN to 48, PDCP SN to 49, and PDCP SN to 50. The uplink data packet is sent to the target network device. After that, the terminal device sends the uplink data packet with the PDCP SN of 51 and later to the target network device.

In other possible situations, the second indication information may include the PDCP SN corresponding to the last uplink data packet in the sequenced uplink data packets successfully sent by the terminal device to the source network device, then the terminal device sends the data to the target network device at this time. The PDCP SN of the first uplink data packet (or the smallest PDCP SN of the uplink data packet sent by the terminal device to the target network device) is the first PDCP SN after the PDCP SN included in the second indication information. In other words, the minimum PDCP SN of the uplink data packet sent by the terminal device to the target network device is the PDCP SN included in the second indication information plus "1".

In some possible descriptions, the second indication information may include the largest PDCP SN in the sequential uplink data packets successfully sent by the terminal device to the source network device, then the smallest uplink data packet sent by the terminal device to the target network device at this time The PDCP SN is the first PDCP SN after the PDCP SN included in the second indication information. In other words, the PDCP SN of the first uplink data packet sent by the terminal device to the target network device is the PDCP SN included in the second indication information plus "1".

As an example, before sending the foregoing first indication information to the terminal device, the source network device has successfully received an uplink data packet with a PDCP SN of 0-50 from the terminal device. At this time, the second indication information may be 50, indicating that the PDCP SN of the first uplink data packet that the terminal device will send to the target network device is 51, or the minimum value of the uplink data packet that the terminal device will send to the target network device The PDCP SN is 51.

As another example, before sending the above-mentioned first indication information to the terminal device, the source network device has successfully received from the terminal device an uplink data packet with a PDCP SN of 0-45 and a PDCP SN of 48, 50. In one implementation, the second indication information may be 45, indicating that the PDCP SN of the first uplink data packet that the terminal device will send to the target network device is 46, and the second indication information can also indicate that the PDCP SN is 46. The upstream data packet was not successfully received by the source network device. That is, the terminal device needs to retransmit the uplink data packet whose PDCP SN is 46. For example, the terminal device sends the uplink data packet whose PDCP SN is 46 to the target network device. Optionally, the terminal device also sends uplink data packets with PDCP SN of 47-50 respectively, and subsequent uplink data packets to the target network device.

In some possible implementations, when the method 500 is executed by the target network device, the target network device may first obtain an uplink PDCP status report from the source network device, and then determine the uplink PDCP status report that the terminal device needs to send to the target network device based on the PDCP status report The minimum PDCP SN of the data packet, or the PDCP status report is sent to the terminal device.

In some possible implementations, when the method 500 is executed by the source network device, the source network device can determine the minimum PDCP SN of the uplink data packet that the terminal device needs to send to the target network device after generating the PDCP status report, and then The minimum PDCP SN is sent to the terminal device. Alternatively, the source network device may send the PDCP status report to the terminal device.

In some possible embodiments of the present application, the PDCP SN included in the foregoing second indication information may be of a bearer granularity. That is, each bearer may have its own corresponding PDCP SN value, and the above PDCP SN corresponding to each bearer may be the same or different, which is not limited in the embodiment of the present application. In the embodiments of the present application, the bearer refers to a radio bearer (RB) between a terminal device and a network device. As an example, the RB may be a data radio bearer (DRB) or a signaling radio bearer (SRB), but the embodiment of the present application is not limited to this.

In a specific example, the RBs established/existed between the terminal device and the network device include RB1 and RB2, and the second indication information may be used to indicate the first PDCP SN corresponding to RB1 and the second PDCP SN corresponding to RB2. Among them, the first PDCP SN and the second PDCP SN may be the same or different.

Exemplarily, the second indication information may be used to indicate the PDCP SN of the first uplink data packet sent by the terminal device on RB1 to the target network device (or the minimum PDCP SN of the uplink data packet sent by the terminal device on RB1 to the target network device) SN), and the second indication information may be used to indicate the PDCP SN of the first uplink data packet sent by the terminal device on RB2 to the target network device (or the smallest value of the uplink data packet sent by the terminal device on RB2 to the target network device) PDCP SN).

Alternatively, the second indication information may be used to indicate the largest PDCP SN in the sequential uplink data packets successfully sent by the terminal device on RB1 to the source network device (or, the sequential uplink data packets successfully sent by the terminal device on RB1 to the source network device) The PDCP SN corresponding to the last uplink data packet in the data packet, and the second indication information can be used to indicate the largest PDCP SN (or, The PDCP SN corresponding to the last uplink data packet in the sequenced uplink data packets successfully sent by the terminal device on the RB2 to the source network device.

Optionally, in addition to the PDCP SN, the foregoing second indication information may also include the RB identity (ID) corresponding to the PDCP SN. Still taking the above example as an example for description, the RBs established/existing between the terminal device and the network device include RB1 and RB2, and the second indication information may be used to indicate the first PDCP SN corresponding to RB1. Optionally, the second indication information further includes the RB ID (such as "1") corresponding to the first PDCP SN. In addition, the second indication information may be used to indicate the second PDCP SN corresponding to RB2. Optionally, the second indication information further includes the RB ID (such as "2") corresponding to the second PDCP SN.

In some optional embodiments, the above-mentioned second indication information may not include the RB ID, and the association relationship between the PDCP SN and the RB contained in the second indication information is agreed by the agreement. For example, the first PDCP SN included in the second indication information corresponds to the smallest RB ID, the second PDCP SN included in the second indication information corresponds to the next smallest RB ID, and so on, the second indication information includes The last PDCP SN corresponds to the largest RB ID. For another example, the first PDCP SN included in the second indication information corresponds to the largest RB ID, the second PDCP SN included in the second indication information corresponds to the second largest RB ID, and so on, the second indication information The last PDCP SN included corresponds to the smallest RB ID. Alternatively, other correspondences between PDCP SN and RB may also be agreed upon, which is not limited in the embodiment of the present application. It should be noted that the maximum/minimum RB ID here refers to the maximum/minimum RB ID corresponding to the RB established/existing between the terminal device and the network device.

In some possible embodiments of the present application, the second indication information may be of bearing granularity. In other words, each bearer may have corresponding second indication information. As an example, the second indication information corresponding to the first bearer may indicate the minimum PDCP SN of the uplink data packet that the terminal device needs to send to the target network device on the first bearer. At this time, the second indication information is of bearer granularity, and it can also be understood that PDCP SN is of bearer granularity.

In a possible implementation manner, when the second indication information is sent on the first bearer, the second indication information may be used to indicate that on the first bearer, the terminal device needs to send the minimum uplink data packet to the target network device. PDCP SN. Optionally, when the network device sends the second indication information, it may also indicate to the terminal device the bearer identifier corresponding to the second indication information. For example, when the second indication information is sent on the first bearer, the network device may indicate to the terminal device the RB ID corresponding to the second indication information, that is, the RB ID corresponding to the first bearer.

Exemplarily, the second indication information may be included in a layer 2 message. For example, the second indication information or other messages may be sent through a PDCP control PDU, which is not limited in the embodiment of the present application. Further, the second indication information corresponding to different bearers can be sent through layer 2 messages (such as PDCP control PDU messages) on each bearer. That is, the layer 2 message sent on a certain bearer can include the corresponding bearer. The second instruction information. Optionally, in addition to the second indication information, the layer 2 message may also include a bearer identifier corresponding to the second indication information.

In a specific example, the network device transmits the second indication information through the PDCP control PDU. For example, if the network device sends the first PDCP control PDU on the first bearer and the first PDCP control PDU contains the second indication information, then On the first bearer, the minimum PDCP SN of the uplink data packet that the terminal device needs to send to the target network device may be determined according to the second indication information included in the first PDCP control PDU. For another example, if the network device sends a second PDCP control PDU on the second bearer, and the second PDCP control PDU contains second indication information, then on the second bearer, the terminal device needs to send an uplink data packet to the target network device The minimum PDCP SN may be determined according to the second indication information included in the second PDCP control PDU.

In a specific example, the network device transmits the second indication information through the RRC message, for example, if the RRC message contains the second indication information corresponding to the first bearer, the second indication information corresponding to the second bearer, and optionally The RRC message also includes the bearer identifier corresponding to the first bearer and the bearer identifier corresponding to the second bearer. On the first bearer, the minimum PDCP SN of the uplink data packet that the terminal device needs to send to the target network device can be based on The second indication information corresponding to the first bearer is determined; on the second bearer, the minimum PDCP SN of the uplink data packet that the terminal device needs to send to the target network device can be determined according to the second indication information corresponding to the second bearer.

In some possible embodiments of the present application, the target network device may also allocate uplink grant (UL grant) information to the terminal device, and the uplink grant information is used for PUSCH transmission between the terminal device and the target network device. The terminal device can obtain the UL grant according to the UL grant information, and use the UL grant to perform uplink data transmission with the target network device. As an example, the UL grant information may include PUSCH resource information, modulation and coding scheme (modulation and coding scheme, MCS) information, etc., which are not limited in the embodiment of the present application.

In some possible situations, when the method 500 is executed by the target network device, the target network device may send the uplink authorization information to the terminal device. In some possible situations, when the method 500 is executed by the source network device, the target network device may send the uplink authorization information to the source network device, and then the source network device sends the uplink authorization information to the terminal device. Correspondingly, the terminal device receives the uplink authorization information. In this way, after receiving the uplink authorization information, the terminal device can send an uplink data packet to the target network device according to the uplink authorization information.

In some optional embodiments, the terminal device may also obtain uplink authorization information in advance. Here, "pre-acquisition" may include indication or pre-defined by network device signaling, for example, protocol definition. Among them, "pre-defined" can be implemented by pre-saving corresponding codes, tables or other methods that can be used to indicate related information in the equipment (for example, including terminal equipment and network equipment). This application does not make any specific implementation methods. limited.

In some possible embodiments, at least one of the first indication information, the second indication information, and the uplink authorization information may be included in the same message and sent to the terminal device, or separately sent to the terminal device in different messages This embodiment of the application does not limit this.

In some possible embodiments, the second indication information may also be used to instruct the terminal device to switch from physical uplink shared channel PUSCH transmission with the source network device to PUSCH transmission with the target network device. At this time, the minimum data convergence protocol PDCP sequence number SN of the uplink data packet that needs to be sent to the target network device after the terminal device is converted to perform PUSCH transmission with the target network device can be instructed to implicitly indicate that the terminal device is transferred from The physical uplink shared channel PUSCH transmission with the source network device is converted to the PUSCH transmission with the target network device. In this manner, the first indication information is optional, that is, the first indication information may not be sent.

As an example, the foregoing message may be an RRC message, or a layer 2 message, or a physical layer message, which is not limited in the embodiment of the present application. Among them, the layer 2 message may be, for example, PDCP control (control) PDU, MAC CE, and so on. The physical layer message may be, for example, downlink control information (DCI) or the like.

In some possible implementations, when the uplink data packet sent by the terminal device to the target network device corresponds to multiple uplink bearers, if the above message is an RRC message, MAC CE, or DCI, the message may also include 2. The RB ID corresponding to the PDCP SN indicated by the indication information, or the RB ID corresponding to the second indication information. If the message carrying the second indication information is a PDCP control PDU, the PDCP control PDU may be sent on its corresponding RB. In this way, the terminal device can determine the RB ID corresponding to the PDCP SN indicated by the second indication information or the RB ID corresponding to the second indication information according to the RB receiving the PDCP control PDU.

In some possible implementations, when the uplink data packet sent by the terminal device to the target network device corresponds to multiple uplink bearers, if the above message is an RRC message, MAC CE, or DCI, the message may not include The RB ID corresponding to the PDCP SN indicated by the second indication information or does not include the RB ID corresponding to the second indication information. At this time, the correspondence between PDCP SN and RB ID can be defined in advance. In some optional embodiments, the network device pre-configures the correspondence between the PDCP SN and the RB ID, or the correspondence between the PDCP SN and the RB ID may be pre-defined by a protocol, which is not limited in the embodiment of the present application.

It should be understood that the examples in the embodiments of the present application are only used to more clearly illustrate the embodiments provided in the present application, and do not limit the technical solutions of the embodiments of the present application.

Therefore, in the embodiments of the present application, the network device instructs the terminal device to transfer the uplink data transmission (for example, PUSCH data transmission) of the terminal device from the source network device to the target network device through the network device. After that, it starts to perform uplink data transmission with the target network device to ensure that the terminal device reduces the UL data transmission interruption delay during the handover process, and further, helps to achieve 0ms UL data transmission interruption. Further, by instructing the terminal device to transmit the minimum PDCP SN or UL grant information of the uplink data packet that needs to be sent to the target network device after converting to PUSCH transmission with the target network device, thereby informing the terminal device how to correctly communicate with the target network device. The network equipment performs uplink data transmission to ensure correct reception on the network equipment side.

FIG. 6 is a schematic flowchart of another data transmission method 600 shown from the perspective of device interaction. In the method 600, the target network device sends the above-mentioned first indication information to the terminal device. It should be understood that FIG. 6 shows the steps or operations of the data transmission method, but these steps or operations are only examples, and the embodiment of the present application may also perform other operations or variations of each operation in FIG. 6. In addition, the various steps in FIG. 6 may be performed in a different order from that presented in FIG. 6, and it is possible that not all the operations in FIG. 6 are to be performed.

601: The source network device sends a handover message to the terminal device.

Correspondingly, the terminal device receives the handover message.

Exemplarily, the handover message may be an RRC reconfiguration message including a synchronization reconfiguration ReconfigurationWithSync cell, or the handover message may be an RRC connection reconfiguration message including a mobility control information MobilityControlInfo cell, which is not limited in this embodiment of the application. .

Optionally, the handover message may contain relevant information of the target cell, such as the physical cell identifier (PCI) of the target cell, frequency information of the target cell, and the temporary cell wireless network identifier assigned by the target cell to the terminal device. (cell radio network temporary identifier, C-RNTI), resource information required to access the target cell, such as random access control channel (RACH) resource information) and so on.

In other possible implementation manners, the target network device may send the handover message to the terminal device, which is not limited in the embodiment of the present application.

602: After the terminal device receives the handover message, the terminal device can still perform PUSCH transmission with the source network device.

As an example, the terminal device may use the first parameter corresponding to the source network device to process the PDCP SDU to be sent to the source network device. For the sender (such as the source network device or the terminal device), the first parameter corresponding to the source network device may include at least one of the following: the header compression context corresponding to the source network device (such as ROHC context), the key corresponding to the source network device, Integrity protection parameters corresponding to the source network device, etc. For example, the terminal device uses the header compression context corresponding to the source network device for header compression, uses the integrity protection parameter corresponding to the source network device for integrity protection, and uses the key corresponding to the source network device for encryption and other processing. For details, please refer to the description in FIG.

In addition, after the terminal device receives the handover message, the terminal device can still perform PDSCH transmission with the source network device. As an example, the terminal device can still receive the PDCP PDU from the source network device. The terminal device may use the second parameter corresponding to the source network device to process the PDCP PDU received from the source network device. For the receiver (such as the source network device or the terminal device), the second parameter corresponding to the source network device includes at least one of the following: the header decompression context corresponding to the source network device (such as ROHC context), the key corresponding to the source network device, Integrity verification parameters corresponding to the source network device, etc. For example, the terminal device uses the key corresponding to the source network device to decrypt, uses the integrity verification parameter corresponding to the source network device to perform integrity verification, and uses the header decompression context corresponding to the source network device to perform header decompression and other processing.

603: The terminal device sends an RRC reconfiguration complete (RRC reconfiguration complete) message to the target network device.

The RRC reconfiguration complete message indicates that the terminal device has successfully switched to the target network device, or indicates that the establishment of the RRC connection/data transmission channel between the terminal device and the target network device is completed.

Correspondingly, the target network device receives the RRC reconfiguration complete message.

As an example, after receiving the handover message, the terminal device can try to handover to the target cell according to the information content contained in the handover message. For example, the terminal device performs a random access procedure with the target cell. After the random access procedure is successful, the terminal device sends an RRC reconfiguration complete (RRC reconfiguration complete) message to the network device to which the target cell belongs (that is, the target network device).

604. After receiving the RRC reconfiguration complete message, the target network device sends third indication information to the source network device, where the third indication information is used to indicate to the source network device that the terminal device has successfully accessed (ie switched) to the target network equipment.

605: After receiving the third indication information, the source network device sends the UL PDCP status report to the target network device.

The UL PDCP status report is generated by the source network device according to the reception status of the uplink data packet received from the terminal device, and is used to indicate the reception status of the uplink data packet sent by the terminal device to the source network device.

Specifically, the UL PDCP status report can be referred to the description in FIG. 5. For brevity, it will not be repeated here.

606. The target network device sends a first message to the terminal device, where the first message includes first indication information, and the first indication information is used to instruct the terminal device to switch from PUSCH transmission with the source network device to PUSCH transmission with the target network device .

Optionally, the first message may also include second indication information, which is used to indicate that the terminal device needs to send the minimum uplink data packet to the target network device after converting to PUSCH transmission with the target network device. PDCP SN. As an example, the second indication information may be a specific value X, or the foregoing UL PDCP status report, which is not limited in the embodiment of the present application. Among them, the value X is used to represent PDCP SN, and X is a natural number.

Optionally, after step 603, the target network device may also allocate uplink authorization information to the terminal device. In some possible implementation manners, the first message may also include uplink authorization information allocated by the target network device to the terminal device.

Specifically, the first indication information, the second indication information, and the uplink authorization information can be referred to the description in FIG. 5, which is not repeated here for brevity.

As an example, the first message may be an RRC message, PDCP control PDU, MAC CE, or DCI, etc., which is not limited in the embodiment of the present application.

In some possible implementation manners, the value X (ie, PDCP SN) and UL PDCP status report may be carried in a granular manner, or the second indication information may be carried in a granular manner. For details, please refer to the description in FIG. 5. For brevity, details are not repeated here.

607: The terminal device performs uplink transmission conversion.

As an example, uplink transmission conversion refers to PUSCH transmission conversion. For example, after the terminal device receives the first message, optionally, once the UL grant information allocated by the target network device is obtained, the terminal device can switch from PUSCH transmission with the source network device to PUSCH transmission with the target network device.

608: After completing the uplink transmission conversion, the terminal device performs PUSCH transmission with the target network device.

As an example, the terminal device maintains PUSCH transmission with the source network device until the first message is received (or until the UL grant information allocated by the target network device is obtained). After receiving the first message (or after obtaining UL grant information allocated by the target network device), the terminal device may perform PUSCH transmission with the target network device. Optionally, if the terminal device is capable of supporting it, after receiving the first message, the terminal device may continue to maintain PUSCH transmission with the source network device until the source network device has a radio link failure.

As an example, the terminal device may use the first parameter corresponding to the target network device to process the PDCP SDU to be sent to the target network device. For the sender (for example, during DL transmission, the sender is the target network device, or during UL transmission, the sender is a terminal device), the first parameter corresponding to the target network device includes at least one of the following: a header corresponding to the target network device Compression context (such as ROHC context), key corresponding to the target network device, integrity protection parameters corresponding to the target network device, etc. For example, starting from the first uplink data packet that needs to be sent to the target network device, the terminal device uses the header compression context corresponding to the target network device for header compression, uses the integrity protection parameters corresponding to the target network device for integrity protection, and uses the target The key corresponding to the network device performs encryption and other processing. For details, please refer to the description in FIG.

After the terminal device successfully switches to the target network device, the terminal device can receive the PDCP PDU from the target network device. The terminal device uses the second parameter corresponding to the target network device to process the PDCP PDU received from the target network device. For the receiver (for example, during UL transmission, the receiver is the target network device, or during DL transmission, the receiver is a terminal device), the second parameter corresponding to the target network device includes at least one of the following: a header corresponding to the target network device Decompression context (such as ROHC context), key corresponding to the target network device, integrity verification parameters corresponding to the target network device, etc. For example, the terminal device uses the key corresponding to the target network device to decrypt, uses the integrity verification parameter corresponding to the target network device to perform integrity verification, and uses the header decompression context corresponding to the target network device to perform header decompression and other processing. For details, please refer to the description in FIG.

Therefore, in the embodiment of the present application, the terminal device is instructed by the network device to indicate the time when the PUSCH data transmission of the terminal device is converted from the source network device to the target network device, which is beneficial to realize that the terminal device starts to communicate with the target network after determining the above-mentioned conversion time. The device performs uplink data transmission to ensure that the terminal device reduces the UL data transmission interruption delay during the handover process, and further, helps to achieve 0ms UL data transmission interruption. Further, by instructing the terminal device to transmit the minimum PDCP SN or UL grant information of the uplink data packet that needs to be sent to the target network device after converting to PUSCH transmission with the target network device, the terminal device is notified how to correctly communicate with the target network device. The network equipment performs uplink data transmission to ensure correct reception on the network equipment side. At this time, the source network device does not need to forward the first indication information, so system signaling overhead can be saved.

FIG. 7 is a schematic flowchart of another data transmission method 700 from the perspective of device interaction. In the method 700, the source network device sends the above-mentioned first indication information to the terminal device. It should be understood that FIG. 7 shows the steps or operations of the data transmission method, but these steps or operations are only examples, and the embodiment of the present application may also perform other operations or variations of each operation in FIG. 7. In addition, the various steps in FIG. 7 may be performed in a different order from that presented in FIG. 7, and it is possible that not all the operations in FIG. 7 are to be performed.

701: The source network device sends a handover message to the terminal device. Correspondingly, the terminal device receives the handover message.

702. After the terminal device receives the handover message, the terminal device can still perform PUSCH transmission with the source network device.

703. The terminal device sends an RRC reconfiguration complete (RRC reconfiguration complete) message to the target network device, indicating that the terminal device has successfully switched to the target network device, or indicating that the RRC connection/data transmission channel between the terminal device and the target network device has been established. .

704. After receiving the RRC reconfiguration complete message, the target network device sends third indication information to the source network device, where the third indication information is used to indicate to the source network device that the terminal device has successfully accessed (ie switched) to the target network equipment.

Specifically, for 701 to 704, please refer to the description of 601 to 604 in FIG.

Optionally, after step 703, the target network device may also allocate uplink authorization information to the terminal device. After allocating the uplink authorization information to the terminal device, the target network device may also send the uplink authorization information to the source network device. In some possible implementation manners, the uplink authorization information and the third indication information may be carried in the same message and sent to the source network device, or sent separately to the terminal device, which is not limited in the embodiment of the present application.

Specifically, the uplink authorization information can be referred to the description in FIG. 5, and for the sake of brevity, it will not be repeated here.

705. The source network device sends a second message to the terminal device, where the second message includes first indication information, and the first indication information is used to instruct the terminal device to switch from PUSCH transmission with the source network device to PUSCH transmission with the target network device .

Optionally, the second message may also include second indication information, which is used to indicate that the terminal device needs to send the minimum uplink data packet to the target network device after converting to PUSCH transmission with the target network device. PDCP SN. As an example, the second indication information may be a specific value X or a UL PDCP status report, which is not limited in the embodiment of the present application. Among them, the value X is used to represent PDCP SN, and X is a natural number.

Optionally, in a case where the source network device receives the uplink authorization information sent by the target network device, the second message may also include the uplink authorization information allocated by the target network device to the terminal device.

As an example, the second message may be an RRC message, PDCP control PDU, MAC CE, or DCI, etc., which is not limited in the embodiment of the present application.

706: The terminal device performs uplink transmission conversion.

707. After completing the uplink transmission conversion, the terminal device performs PUSCH transmission with the target network device.

Specifically, 706 and 707 can be referred to the descriptions of 607 and 608 in FIG.

Therefore, in the embodiment of the present application, the terminal device is instructed by the network device to indicate the time when the PUSCH data transmission of the terminal device is converted from the source network device to the target network device, which is beneficial to realize that the terminal device starts to communicate with the target network after determining the above-mentioned conversion time. The device performs uplink data transmission to ensure that the terminal device reduces the UL data transmission interruption delay during the handover process, and further, helps to achieve 0ms UL data transmission interruption. Further, by instructing the terminal device to transmit the minimum PDCP SN or UL grant information of the uplink data packet that needs to be sent to the target network device after converting to PUSCH transmission with the target network device, the terminal device is notified how to correctly communicate with the target network device. The network equipment performs uplink data transmission to ensure correct reception on the network equipment side.

At this time, optionally, the source network device may receive the first indication information from the target network device and/or the minimum PDCP SN of the uplink data packet that the terminal device needs to send to the target network device. At this time, the source network device forwards the first indication information and/or the minimum PDCP SN of the uplink data packet that the terminal device needs to send to the target network device, which can be more flexible to indicate the above conversion time and/or terminal device needs to the terminal device The minimum PDCP SN of the uplink data packet sent to the target network device.

In the embodiment of the present application, after the source network device sends a handover message to the terminal device, data can be forwarded with the target network device. FIG. 8 shows a schematic diagram of the user plane protocol stack architecture on the network device side corresponding to downlink (DL) data transmission. As shown in Figure 8, after receiving PDCP SDUs from a user plane function (UPF), the source network device can allocate PDCP SNs to the PDCP SDUs respectively. The source network device may forward all or part of the PDCP SDUs allocated with the PDCP SN and the PDCP SN (PDCP SDUs with associated PDCP SN) associated with each of the PDCP SDUs to the target network device. PDCP SDUs that are not forwarded to the target network device are processed by the source network device such as header compression, encryption, and header addition, and then sent to the terminal device via the RLC1, MAC1, and PHY1 of the source network device. These PDCP SDUs forwarded to the target network device are processed by the target network device such as header compression, encryption, and header addition, and then sent to the terminal device via the RLC2, MAC2, and PHY2 of the target network device.

It should be noted that FIG. 8 shows an example of the PDCP layer, but the embodiment of the present application is not limited to this. As an example, FIG. 8 shows some of the functions of the PDCP layer. For details, refer to the description in FIG. 4.

In a possible implementation manner, duplication can be performed on the network device side, that is, for data corresponding to a certain PDCP SN, the source network device can produce 2 PDCP SDUs. One of the PDCP SDUs is compressed and encrypted by the source network device itself, that is, compressed using the header compression context of the source network device (for example, header compression #1 in Figure 8), encrypted using the key of the source network device, etc. After processing (such as encryption #1 in Figure 8), a PDCP PDU is generated, and then sent by the source network device to the terminal device. Another PDCP SDU is forwarded by the source network device to the target network device, and the target network device performs compression, encryption, etc., that is, uses the header compression context of the target network device for compression (for example, header compression #2 in Figure 8), use After the key of the target network device is encrypted and other processing (such as encryption #2 in FIG. 8), a PDCP PDU is generated. When the terminal device successfully connects to the target network device (for example, after the terminal device sends an RRC reconfiguration complete message to the target network device), the target network device can send the above-mentioned PDCP PDU(s) processed by the target network device to the terminal equipment.

In another possible implementation manner, the network device side may not perform duplication, that is, the source network device may receive one or more PDCP SDU(s) from the UPF, and the source network device's own PDCP layer performs header compression, After encryption and other processing, it is sent to the terminal device. Alternatively, the source network device can allocate PDCP SN to one or more PDCP SDU(s) received from UPF, and then forward these PDCP SDU(s) (ie, PDCP SDUs with associated PDCP SN) respectively allocated with PDCP SN For the target network device, the target network device performs header compression and encryption. When the terminal device successfully accesses the target network device, the target network device can send the PDCP PDU(s) processed by the target network device to the terminal device.

For the terminal device, after receiving the handover message, the terminal device can maintain the data transmission with the source network device, that is, the terminal device side maintains the user plane protocol stack architecture corresponding to the source network device, and the user plane protocol corresponding to the source network device The stack does not perform layer 2 recovery/re-establishment. In addition, the terminal device establishes a user plane protocol stack architecture corresponding to the target network device for random access and data transmission with the target network device. Among them, layer 2 includes the MAC/RLC/PDCP protocol layer.

Before the terminal device releases the connection with the source network device, the terminal device maintains two sets of security keys (also referred to as security contexts)/two sets of header compression contexts (or header decompression contexts). The terminal device uses the corresponding key/header decompression context to process the received data packet (PDCP PDU(s)) according to whether the received data packet comes from the source network device or the target network device. Specifically, for the PDCP PDU(s) received from the source network device, the terminal device uses the security key corresponding to the source network device to decrypt, and the header decompression context corresponding to the source network device performs header decompression and other processing. For the PDCP PDU(s) received from the target network device, the terminal device uses the security key corresponding to the target network device to decrypt, and the header decompression context corresponding to the target network device performs header decompression and other processing.

After the terminal device successfully accesses the target network device, it can use the header decompression context corresponding to the target network device and the key corresponding to the target network device to process the data packets (PDCP PDU(s)) received from the target network device. However, for example, assuming that the network device side does not support packet duplication, even if the terminal device has received downlink data packets from the target network device at this time, the source network device may have unsuccessfully sent DL data to the terminal device. The time source network device needs to forward these unsuccessfully sent DL data packets to the target network device, and then the target network device sends it to the terminal device. If the source network device transfers to the target network device the PDCP SDU(s) each assigned with PDCP SN, after the target network device receives these PDCP SDU(s) each assigned with PDCP SN, it uses the corresponding header compression of the target network device The context and the key corresponding to the target network device perform header compression and encryption on these PDCP SDUs. However, this may cause the terminal device to fail to correctly receive the DL data received from the target network device. For example, the packets for header decompression are required to be in order. For example, when robust header compression (ROHC)/decompression requires data packets to be in order, the terminal device is required to be in order when receiving from the target network device. Before the data packets that need to be retransmitted by the target network device are not successfully sent on the source network device side, the data packets with the sequence numbers after these retransmitted data packets have been received from the target network device. Therefore, the terminal device receives the data packets from the network device side. The PDCP SN of the received downlink data packet is out of order, which will cause the header decompression of the terminal device to be out of order/failure, which will cause the DL reception to fail.

As an example, after the source network device sends a handover message to the terminal device, for a certain DL bearer, the source network device continues to send PDCP SN 10-100 data packets to the terminal device, that is, the source network device uses its own corresponding After the header compression context performs header compression and its own key is encrypted, it is sent to the terminal device. In addition, the source network device can forward PDCP SDUs with PDCP SN 101-120 to the target network device. The target network device uses the header compression context corresponding to the target network device, and the key pair PDCP SN corresponding to the target network device is 101- After 120 PDCP SDUs undergo header compression, encryption, and other processing, PDCP PDUs are generated. After the terminal device successfully connects to the target network device, the target network device can send PDCP PDUs starting with PDCP SN 101 to the terminal device in sequence. That is to say, the target network device sends PDCP PDUs of 101, 102, ... obtained by processing the header compression context/key on the target network device side to the terminal device. If the target network device sends a PDCP SN 110 data packet to the terminal device, it receives the PDCP SN 90-100 data packet forwarded by the source network device (that is, the source network device fails to successfully set the PDCP SN to 90). -100 data packets are sent to the terminal device). At this time, if the target network device uses its own corresponding header compression context and its own key to perform header compression and encryption on PDCP SDUs with a PDCP SN of 90-100, it will cause the terminal device to be unable to correctly perform processing from the target network device. DL data reception.

Based on this, the embodiment of the present application provides a data transmission method, which forwards at least one PDCP PDU(s) that was not successfully sent to the terminal device to the target network device through the source network device, instead of forwarding the unsuccessful forwarding to the target network device. PDCP SDU(s), so that the target network device does not need to use its own header compression context and key to process the DL data that has not been successfully sent by the source network device, which can help the terminal device to correctly access the target network device Perform DL data reception.

FIG. 9 is a schematic flowchart of a data transmission method 900 from the perspective of device interaction. It should be understood that FIG. 9 shows the steps or operations of the data transmission method, but these steps or operations are only examples, and the embodiment of the present application may also perform other operations or variations of each operation in FIG. 9. In addition, the various steps in FIG. 9 may be performed in a different order from that presented in FIG. 9, and it is possible that not all the operations in FIG. 9 are to be performed. As shown in FIG. 9, the data transmission method may include steps 901 to 906.

901: The source network device determines that it fails to send a downlink data packet to the terminal device.

After the source network device sends a handover message to the terminal device, the source network device can continue to send downlink data packets to the terminal device. For example, the source network device sends a part of PDCP PDU(s) generated after processing by itself to the terminal device. In addition, the source network device may forward part of the PDCP SDU(s) allocated with PDCP SN to the target network device, and the target network device processes these PDCP SDU(s) to generate PDCP PDU(s). After the terminal device successfully accesses the target network device, the target network device can send the PDCP PDU(s) generated after processing by itself to the terminal device.

In some possible implementations, after the terminal device has successfully connected to the target network device, or after the target network device has sent PDCP PDU(s) to the terminal device, 901 occurs, that is, the source network device determines to Part or all of the PDCP PDU(s) sent by the device failed. In FIG. 9, the PDCP PDU(s) that the source network device fails to send to the terminal network device may be referred to as the first PDCP PDU(s).

As an example, after the source network device sends a handover message to the terminal device, the source network device continues to send to the terminal device PDCP SN 10-100 DL packets, that is, the source network device uses the header compression context and source corresponding to the source network device. The integrity protection parameters corresponding to the network device and the key corresponding to the source network device perform header compression, integrity protection, and encryption on the PDCP SDUs whose PDCP SN is 10-100 respectively, and then send the generated PDCP PDUs to the terminal equipment. In addition, after the source network device sends a handover message to the terminal device, the source network device can send PDCP SDUs with PDCP SN 101-120 to the target network device, that is, the source network device sends the target network device to the target network device with PDCP SN assigned PDCP SDUs and the PDCP SN associated with each PDCP SDU. In other words, what the source network device sends to the target network device is PDCP SDUs with associated PDCP SN. However, when the terminal device has successfully connected to the target network device, or after the terminal device has been able to perform downlink data transmission with the target network device, for example, when the terminal device has adopted the header compression context corresponding to the target network device, and the target network device corresponding After the integrity protection parameters and the key corresponding to the target network device are processed separately for the PDCP PDUs with SN 101-110 received from the target network device, the source network device finds that the PDCP SN is not successfully changed to 90- 100 PDCP PDUs are sent to the terminal device (in other words, PDCP SDUs with a PDCP SN of 90-100 are not successfully sent to the terminal device). Here, the PDCP PDUs with the PDCP SN of 90-100 are an example of the foregoing first PDCP PDU(s).

In a possible implementation manner, after the source network device performs header compression and encryption on a certain PDCP SDU, it obtains the PDCP PDU corresponding to the PDCP SDU. Then, the source network device sends the PDCP PDU to the terminal device, and when the terminal device successfully receives the PDCP PDU, it feeds back an acknowledgement (acknowledge, ACK) for the PDCP PDU to the source network device. When the source network device does not receive the ACK for the PDCP PDU sent by the terminal device within a specified time period after the PDCP PDU is sent to the terminal device, it can be considered that the PDCP PDU is not successfully sent. Or, when the source network device receives the NACK for the PDCP PDU sent by the terminal device, it can be considered that the PDCP PDU was not successfully sent.

902: The source network device sends the first PDCP PDU(s) in step 901 to the target network device.

In other words, for at least one PDCP SDU(s) that the source network device failed to successfully send to the terminal device, the source network device uses its own corresponding header compression context, integrity protection parameters, keys, etc., to the at least one PDCP SDU(s). s) After processing, generate at least one corresponding PDCP PDU(s), and then, the source network device sends the at least one PDCP PDU(s) to the target network device. Correspondingly, the target network device receives the at least one PDCP PDU(s).

Continuing the example in 901, at this time, the source network device may send PDCP PDUs with a PDCP SN of 90-100 to the target network device. Among them, PDCP PDUs with a PDCP SN of 90-100 are generated by the source network device after processing using its own corresponding header compression context, integrity protection parameters, keys, and so on.

It should be noted that, here only the PDCP SN is 90-100 respectively as an example for description, but the embodiment of the present application is not limited to this. Here, the PDCP SN corresponding to the unsuccessfully sent downlink data packets may be continuous or non-continuous, and both fall within the protection scope of the embodiments of the present application. As an example, the PDCP SN corresponding to the unsuccessfully sent downlink data packet may be 95 and 98, respectively.

In some possible embodiments, step 903 may be performed, that is, the source network device sends fourth indication information to the terminal device, and the fourth indication information is used to indicate that at least one PDCP PDU(s) in step 902 (ie, the first PDCP PDU( s)) One-to-one correspondence with at least one PDCP SN, that is, at least one PDCP PDU(s) (i.e., the first PDCP PDU(s)) that the source network device did not successfully send to the terminal device in step 901 corresponds to at least one PDCP one-to-one SN. Correspondingly, the terminal device receives the fourth indication information.

In some possible implementations, the fourth indication information may include at least one PDCP SN respectively associated with at least one PDCP PDU(s) (that is, the first PDCP PDU(s)) in step 902, that is, the fourth indication information may Including the PDCP SN corresponding to each PDCP PDU in the first PDCP PDU(s). In other possible implementation manners, the fourth indication information may include the smallest PDCP SN in at least one PDCP PDU(s) (that is, the first PDCP PDU(s)) in step 902, and a bitmap. The bitmap can be used to indicate the PDCP PDU corresponding to the smallest PDCP SN and the reception status of the subsequent PDCP PDU. For example, the fourth indication information may include 95 and 011011, indicating that PDCP PDUs with SNs of 95 and 98 were not successfully sent, and PDCP PDUs with SNs of 96, 97, 99, and 100 were successfully sent.

In some possible embodiments, step 903 may not be executed, but step 903' may be executed, where 903' includes steps 904 and 905.

904. The source network device sends fourth indication information to the target network device, where the fourth indication information is used to indicate at least one corresponding to at least one PDCP PDU(s) (ie, the first PDCP PDU(s)) in step 902. PDCP SN, that is, at least one PDCP SN that has a one-to-one correspondence with at least one PDCP PDU(s) (that is, the first PDCP PDU(s)) that the source network device did not successfully send to the terminal device in step 901. Correspondingly, the target network device receives the fourth indication information.

905: The target network device sends the foregoing fourth instruction information to the terminal device. Correspondingly, the terminal device receives the fourth indication message.

That is, in step 903, the source network device indicates to the terminal device the PDCP SN corresponding to the downlink data packets that are not successfully sent to the terminal device in step 901. In step 903', the source network device may first indicate to the target network device the PDCP SN corresponding to the downlink data packets that were not successfully sent to the terminal device in step 901, and then the target network device indicates to the terminal device that the unsuccessful transmission to the terminal device The PDCP SN corresponding to the downlink data packet of the terminal device.

In this embodiment of the application, at least one PDCP SN corresponding to at least one PDCP SDU(s) (that is, the first PDCP PDU(s)) that is not successfully sent to the terminal device may be continuous or non-continuous. This depends on the at least one PDCP PDU(s) (that is, the first PDCP PDU(s)) forwarded by the source network device to the target network device in step 902. As an example, when the PDCP SN corresponding to at least one PDCP PDU(s) (that is, the first PDCP PDU(s)) forwarded by the source network device to the target device in step 902 is 90-100, the fourth indication information indicates The PDCP SN of is 90-100, for example, the fourth indication information includes a value of 90-100. When the PDCP SN corresponding to at least one PDCP PDU(s) (that is, the first PDCP PDU(s)) forwarded by the source network device to the target network device in step 902 is 95 and 98, the PDCP indicated by the fourth indication information The SN are respectively 95 and 98. For example, the fourth indication information includes the values 95 and 98.

Exemplarily, the fourth indication information in step 904 may be carried in an Xn message or X2 message. For example, the Xn message or X2 message is an SN status transfer (SN status transfer) message, or other messages. Not limited.

Exemplarily, the fourth indication information in step 903 or step 905 may be carried in an RRC message, or a layer 2 message, or a physical layer message, which is not limited in the embodiment of the present application. The layer 2 message may be, for example, PDCP control PDU, MAC CE, etc., the physical layer message may be DCI, and the RRC message may be an RRC reconfiguration message, which is not limited in this embodiment.

In some possible embodiments, the PDCP SN indicated by the fourth indication information may be of bearer granularity, that is, different bearers may have their respective corresponding PDCP SNs. Alternatively, the fourth indication information may be of bearing granularity. The embodiments of this application do not limit this. Specifically, the carrying granularity of the fourth indication information is similar to the carrying granularity of the second indication information, and reference may be made to the description of the second indication information above. For brevity, details are not repeated here.

906: The target network device sends the first PDCP PDU(s), that is, the at least one PDCP PDU(s) described in step 902, to the terminal device. Correspondingly, the terminal device receives the first PDCP PDU(s) from the target network device.

For a PDCP PDU received from the target network device, if the PDCP SN corresponding to the PDCP PDU is included in the PDCP SN indicated by the fourth indication information, the terminal device uses the header decompression context corresponding to the source network device to perform the header Decompress, use the key corresponding to the source network device for decryption and other processing. If the PDCP SN corresponding to the PDCP PDU is not included in the PDCP SN indicated by the fourth indication information, the terminal device uses the header decompression context corresponding to the target network device to perform header decompression, and uses the key corresponding to the target network device to perform header decompression. Decryption and other processing.

As an example, when the PDCP SN indicated by the fourth indication information is 90-100, for example, when the fourth indication information is a value of 90-100, it can be understood that the fourth indication information is used to instruct the terminal device to receive information from the target network device. The received PDCP SNs are respectively 90-100 PDCP PDUs. Use the header decompression context corresponding to the source network device and the key corresponding to the source network device to perform header decompression, decryption, etc., then the terminal device receives from the target network device When the PDCP SN is 90-100 PDCP PDUs, the header decompression context corresponding to the source network device is used for header decompression, and the key corresponding to the source network device is used for decryption and other processing. When the terminal device receives PDCP PDUs with PDCP SN 101-120 from the target network device, it uses the header decompression context corresponding to the target network device to minus the header decompression, and uses the key corresponding to the target network device to perform decryption and other processing.

In some possible implementation manners, the order in which the terminal device receives data packets from the network device side (such as the source network device and/or the target network device) may not be limited. In other words, the terminal device may first receive the PDCP PDU corresponding to any PDCP SN in the PDCP SN 101-120, and then receive the PDCP PDU corresponding to any PDCP SN in the PDCP SN 90-100; or First receive the PDCP PDU corresponding to any PDCP SN of 90-100, and then receive the PDCP PDU corresponding to any PDCP SN of 101-120.

Therefore, in the embodiment of the present application, the source network device forwards at least one PDCP PDU(s) (that is, the first PDCP PDU(s)) that is not successfully sent to the terminal device to the target network device, and the target network device transmits the at least one PDCP PDU(s) to the target network device. The PDCP PDU(s) is sent to the terminal device, and the source network device or the target network device indicates to the terminal device that the at least one PDCP PDU(s) corresponds to at least one PDCP SN, and for the at least one PDCP SN received from the target network device For part or all of PDCP PDU(s), the terminal device uses the header compression context and key corresponding to the source network device to process, so that the terminal device can correctly receive DL data from the target network device.

The embodiment of the application also provides a data transmission method. After obtaining the reception status/status report for the downlink data packet sent by the source network device to the terminal device, the target network device can start to check the PDCP SDU in its own buffer area. (s) Carry out the corresponding treatment. In other words, before obtaining the reception status/status report for the downlink data packet sent by the source network device to the terminal device, if the target network device receives the PDCP SDU(s) forwarded by the source network device, the target network device is not correct These PDCP SDU(s) are processed accordingly, but are stored in its own buffer area. After obtaining the receiving status/status report for the downlink data packet sent by the source network device to the terminal device, the target network device performs header compression and encryption on all PDCP SDU(s) in its own buffer area, and then communicates with the terminal device. The device performs downlink data transmission. Here, all PDCP SDU(s) include PDCP SDU(s) that the source network device has not successfully sent to the terminal device, and PDCP SDU(s) that the source network device forwards to the target network device and needs to be sent by the target network device to the terminal device. In this way, for the PDCP PDU(s) received from the target network device, the terminal device can use the key corresponding to the target network device to decrypt, and the header decompression context corresponding to the target network device to perform header decompression and other processing, so that the terminal The device can correctly receive DL data from the target network device.

FIG. 10 is a schematic flowchart of a data transmission method 1000 from the perspective of device interaction. It should be understood that FIG. 10 shows the steps or operations of the data transmission method, but these steps or operations are only examples, and the embodiment of the present application may also perform other operations or variations of each operation in FIG. 10. In addition, the various steps in FIG. 10 may be performed in a different order from that presented in FIG. 10, and it is possible that not all operations in FIG. 10 are to be performed. As shown in FIG. 10, the data transmission method may include steps 1001 to 1006.

1001. The source network device sends the first PDCP SDU to the target network device.

Correspondingly, the target network device receives the first PDCP SDU. The first PDCP SDU may include one PDCP SDU or include multiple PDCP SDUs.

As an example, after sending a handover message to the terminal device, the source network device may forward at least one PDCP SDU(s) assigned with a PDCP SN and its associated PDCP SN (PDCP SDUs with associated PDCP SN) to the target network device.

Specifically, after sending the handover message to the terminal device, the source network device sends the first PDCP SDU allocated with the PDCP SN and the PDCP SN respectively associated with each PDCP SDU of the first PDCP SDU to the target network device.

In one example, the source network device uses a general packet radio service tunnelling protocol user (GPRS tunnelling protocol user, GTP-U) extension header (extension header) to send the PDCP SN to the target network device. For example, for a certain PDCP SDU in the first PDCP SDU, the source network device can send the PDCP SN corresponding to the PDCP SDU through the GTP-U extension header corresponding to the PDCP SDU (that is, the source network device can send to the target network device The GTP-U extension header corresponding to the PDCP SDU, and the GTP-U extension header contains the PDCP SDU corresponding to the PDCP SDU. The source network device can use the GTP-U corresponding to each PDCP SDU in the first PDCP SDU. The U extension header is used to respectively send the PDCP SN corresponding to each PDCP SDU in the first PDCP SDU.

Optionally, the source network device can send to the target network device the hyperframe number (hyperframe number, HFN) corresponding to each PDCP SDU in the first PDCP SDU through the SN status transfer message, that is, the SN status transfer message can Contains the HFN corresponding to each PDCP SDU in the first PDCP SDU. Or, optionally, the source network device may send the hyperframe number (HFN) corresponding to at least one PDCP SDU in the first PDCP SDU to the target network device through the SN status transfer message, that is, the SN status transfer message May include at least one HFN, and the at least one HFN corresponds to at least one PDCP SDU in the first PDCP SDU. Or, optionally, the source network device can send the hyperframe number (hyperframe number, HFN) corresponding to any PDCP SDU in the first PDCP SDU to the target network device through the SN status transfer message, that is, in the SN status transfer message It may include the HFN corresponding to any one of the PDCP SDUs in the first PDCP SDU. For example, the source network device can send to the target network device the PDCP SDU corresponding to the smallest PDCP SN in the first PDCP SDU through the SN status transfer message. HFN, or the source network device can send the HFN corresponding to the PDCP SDU corresponding to the largest PDCP SN in the first PDCP SDU to the target network device through the SN status transfer message, or the source network device can send the SN status transfer message to the target network device. The network device sends the HFN corresponding to the PDCP SDU corresponding to any PDCP SN in the first PDCP SDU, which is not limited in the embodiment of the present application.

Or, in another example, the source network device uses the GTP-U extension header to send the PDCP SN to the target network device. For example, for a certain PDCP SDU in the first PDCP SDU, the source network device can use the GTP-U corresponding to the PDCP SDU. U extension header to send the PDCP SN corresponding to the PDCP SDU (that is, the source network device can send the GTP-U extension header corresponding to the PDCP SDU to the target network device, and the GTP-U extension header includes the PDCP SN corresponding to the PDCP SDU ), the source network device may respectively send the PDCP SN corresponding to each PDCP SDU in the first PDCP SDU through the GTP-U extension header corresponding to each PDCP SDU in the first PDCP SDU respectively. Optionally, the source network device sends the COUNT value corresponding to at least one PDCP SDU in the first PDCP SDU to the target network device through the SN status transfer message, and the COUNT value may refer to the COUNT value of the uplink data packet and/or the downlink data The COUNT value of the packet, specifically, the COUNT value can include the PDCP SN value and the HFN value. That is, the SN status transfer message may include the COUNT value corresponding to at least one PDCP SDU in the first PDCP SDU, respectively.

Or, optionally, in the above two examples, the source network device can use the user plane protocol stack to send PDCP SN to the target network device. For details, refer to the protocol TS38.425, or the source network device can use the protocol data unit (protocol data unit). Unit, PDU) The session (session) user plane protocol stack sends the PDCP SN to the target network device. For details, please refer to the protocol TS38.415. I won't repeat them here.

Or, in another example, the source network device sends the COUNT value corresponding to at least one PDCP SDU in the first PDCP SDU to the target network device through the SN status transfer message, and the COUNT value may refer to the COUNT value of the uplink data packet and/ Or the COUNT value of the downstream data packet. Specifically, the COUNT value may include the PDCP SN value and the HFN value. That is, the SN status transfer message may include the COUNT value corresponding to at least one PDCP SDU in the first PDCP SDU. In this example, it is not necessary to send the PDCP SN through the GTP-U extension header. This embodiment does not limit this.

1002. The source network device determines that it fails to send a downlink data packet to the terminal device.

After the source network device sends the handover message to the terminal device, the downlink data packet sent to the terminal device may fail to be sent. For example, the source network device may send part of the PDCP SDU(s) to the terminal device after header compression and encryption are performed by the source network device itself. In step 1002, some or all of the PDCP SDU(s) in this part of PDCP SDU(s) may fail to be sent. Here, these PDCP SDU(s) that have failed to send may be referred to as the second PDCP SDU. The second PDCP SDU may include one PDCP SDU or include multiple PDCP SDUs.

It should be noted that the order of execution of step 1001 and step 1002 is not limited. For example, step 1001 can be executed before step 1002, or step 1001 can be executed after step 1002, or step 1001 and step 1002 can be executed simultaneously .

1003. The source network device sends the second PDCP SDU to the target network device. Correspondingly, the target network device receives the second PDCP SDU.

As an example, after the source network device sends a handover message to the terminal device, the source network device continues to send the terminal device PDCP SN 10-100 DL data packets, that is, the source network device uses the header compression context and source corresponding to the source network device. The integrity protection parameters corresponding to the network device and the key corresponding to the source network device perform header compression, integrity protection, and encryption on the PDCP SDUs whose PDCP SN is 10-100 respectively, and then send the generated PDCP PDUs to the terminal equipment. In addition, after the source network device sends a handover message to the terminal device, it can send PDCP SDUs with PDCP SN 101-120 to the target network device, that is, the source network device sends PDCP SDUs with PDCP SN assigned to the target network device. , And the PDCP SN associated with each PDCP SDU. In other words, what the source network device sends to the target network device is PDCP SDUs with associated PDCP SN. After the target network device receives the PDCP SDUs with the PDCP SN of 101-120 respectively, it can be stored in the buffer area, but does not perform header compression, encryption, and other processing on these PDCP SDUs. A possible situation is that the source network device finds that it has not successfully sent PDCP PDUs with a PDCP SN of 90-100 to the terminal device (in other words, it has not successfully sent PDCP SDUs with a PDCP SN of 90-100 to the terminal device. ). Here, PDCP SDUs with PDCP SNs 101-120 are an example of the first PDCP SDU, and PDCP SDUs with PDCP SNs 90-100 are an example of the second PDCP SDU. At this time, the source network device may forward PDCP SDUs (PDCP SDUs with associated PDCP SN) with a PDCP SN of 90-100 to the target network device, that is, the source network device sends the second PDCP SDU to the target network device.

1004. The terminal device sends fifth indication information to the target network device, where the fifth indication information is used to indicate that the terminal device has not successfully received the second PDCP SDU from the source network device. As an example, the fifth indication information may be used to indicate that the terminal device does not have the PDCP SN corresponding to the second PDCP SDU successfully received from the source network device.

In a possible implementation manner, the fifth indication information may be a PDCP status report. The PDCP status report is used to indicate the reception status of the downlink data packet received by the terminal device from the source network device. For example, the PDCP status report may be used for Indicate the receiving status of the downlink data packets whose PDCP SN is 90-100. The target network device may determine, according to the PDCP status report, that the terminal device has not successfully received the second PDCP SDU from the source network device. As an example, it may be determined that the terminal device does not have the PDCP SN corresponding to the first PDCP SDU successfully received from the source network device.

As an example, the PDCP status report may include the reception status of data packets whose PDCP SN is 10-100, where the reception status of data packets whose PDCP SN is 10-89 is received successfully, and PDCP SN is 90-100 data. The receiving status of the packet is receiving failure. Alternatively, the PDCP status report may include the reception status of data packets whose PDCP and SN are 60-100, which is not limited in this embodiment.

In other possible implementation manners, the terminal device may also send the PDCP status report to the source network device, and the source network device sends the PDCP status report to the target network device.

In some possible embodiments, the PDCP SN indicated by the fifth indication information may be of bearer granularity, that is, different bearers may have their respective corresponding PDCP SNs. Alternatively, the fifth indication information may be of bearing granularity. The embodiments of this application do not limit this. Specifically, the carrying granularity of the fifth indication information is similar to the carrying granularity of the second indication information. Refer to the above description of the second indication information. For brevity, details are not repeated here.

It should be noted that the order of execution of step 1003 and step 1004 is not limited. For example, step 1003 can be executed before step 1004, or step 1003 can be executed after step 1004, or step 1003 and step 1004 can be executed simultaneously .

1005. After receiving the fifth indication information, the target network device may use its corresponding parameters to process the first PDCP SDU and the second PDCP SDU. As an example, the target network device uses the header compression context corresponding to the target network device to compress the first PDCP SDU and the second PDCP SDU, and uses the key corresponding to the target network device to encrypt the first PDCP SDU and the second PDCP SDU, etc. deal with. Among them, the target network device can first perform header compression and encryption on the second PDCP SDU, and then perform header compression and encryption on the first PDCP SDU; or, the target network device can use other processing methods, which are not limited. .

It should be noted that step 1005 is executed after step 1004. That is to say, the target network device only starts the corresponding processing of the PDCP layer after learning the reception status of all the downlink data packets sent by the source network device to the terminal device. That is, before receiving the fifth indication information, the target network device does not process the PDCP SDU(s) received from the source network device, for example, the first PDCP SDU and the second PDCP SDU. . After receiving the fifth indication information, the target network device performs header compression and encryption on the first PDCP SDU and the second PDCP SDU. Correspondingly, after header compression and encryption are performed on the first PDCP SDU, the first PDCP PDU is obtained, and after header compression and encryption are performed on the second PDCP SDU, the second PDCP PDU is obtained.

1006. The target network device sends the first PDCP PDU and the second PDCP PDU to the terminal device. Specifically, the target network device may first send the second PDCP PDU to the terminal device, and then send the first PDCP PDU. Correspondingly, the terminal device receives the first PDCP PDU and the second PDCP PDU, and uses the parameters corresponding to the target network device to process the first PDCP PDU and the second PDCP PDU. For example, use the header decompression context corresponding to the target network device to decompress the first PDCP PDU and the second PDCP PDU, and use the key corresponding to the target network device to decrypt the first PDCP PDU and the second PDCP PDU. Specifically, the terminal device may first perform header decompression and decryption processing on the second PDCP PDU, and then perform header decompression and decryption processing on the first PDCP PDU.

Therefore, in this embodiment of the application, the target network device may, after acquiring the reception status of the downlink data packet sent by the source network device to the terminal device, forward the source network device to all PDCP SDUs of the target network device for header compression, encryption, etc. Processing and sending to the terminal device, the terminal device can use the header decompression context corresponding to the target network device to perform header decompression and the security key corresponding to the target network device to decrypt, so that the terminal device can correctly perform processing from the target network device DL data reception.

The embodiment of the application also provides a data transmission method. It is assumed that when the target network device has successfully sent a downlink data packet with a PDCP SN of Y to the terminal device, the source network device will unsuccessfully send the PDCP SDU( s) Send to the target network device. At this time, the target network device regards the PDCP SN corresponding to these PDCP SDU(s) as (Y+1), (Y+2), (Y+3)..., and the target network device forwards the source network device The received PDCP SDU(s) that are not successfully sent to the terminal device are sent to the terminal device after header compression and encryption are performed on these PDCP SDU(s) using the header compression context and key corresponding to the target network device. In addition, the terminal device can be notified of the corresponding processing method, so that the terminal device can correctly decompress and decrypt the received PDCP PDUs, thereby helping the terminal device to correctly receive DL data from the target network device.

FIG. 11 is a schematic flowchart of a data transmission method 1100 from the perspective of device interaction. It should be understood that FIG. 11 shows the steps or operations of the data transmission method, but these steps or operations are only examples, and the embodiment of the present application may also perform other operations or variations of each operation in FIG. 11. In addition, the various steps in FIG. 11 may be performed in a different order from that presented in FIG. 11, and it is possible that not all operations in FIG. 11 are to be performed. As shown in FIG. 11, the admission control method may include steps 1101 to 1107.

1101. The source network device sends the first PDCP SDU to the target network device.

Correspondingly, the target network device receives the first PDCP SDU. After the target network device receives the first PDCP SDU, it uses the header compression context and key corresponding to the target network device to perform corresponding processing. The first PDCP SDU may include one PDCP SDU or include multiple PDCP SDUs.

As an example, after sending a handover message to the terminal device, the source network device may forward at least one PDCP SDU(s) assigned with a PDCP SN and its associated PDCP SN (PDCP SDUs with associated PDCP SN) to the target network device. After the target network device receives the at least one PDCP SDU(s), it uses the header compression context, key, etc., corresponding to the target network device to perform header compression, encryption, and other processing.

1102: The source network device fails to send a downlink data packet to the terminal device. The PDCP SDU(s) whose transmission fails are called the second PDCP SDU. The second PDCP SDU may include one PDCP SDU or include multiple PDCP SDUs. For details, refer to step 1002 in FIG. 10.

It should be noted that the order of execution of step 1101 and step 1102 is not limited. For example, step 1101 can be executed before step 1102, or step 1101 can be executed after step 1102, or step 1101 and step 1102 can be executed simultaneously .

1103. The target network device sends a fourth PDCP PDU to the terminal device. Among them, the fourth PDCP PDU is the PDCP PDU corresponding to the part of the PDCP SDU (such as the fourth PDCP SDU) in the first PDCP SDU in step 1101, that is, the fourth PDCP PDU is the part of the PDCP of the first PDCP SDU from the target network device SDU (such as the fourth PDCP SDU) is generated after processing. Wherein, the fourth PDCP PDU may include one PDCP PDU or include multiple PDCP PDUs.

Specifically, the target network device may use the header compression context, key, etc., corresponding to the target network device to perform corresponding processing on the fourth PDCP SDU. Optionally, the target network device sends the fourth PDCP PDU obtained after processing to the terminal device.

Here, the PDCP SN corresponding to the fourth PDCP PDU is consistent with the PDCP SN corresponding to the fourth PDCP SUD, that is, the PDCP SN that is always allocated to the source network device can be recorded as the fourth PDCP SN.

Step 1103 occurs after the terminal device successfully accesses/switches to the target network device. For example, after the target network device receives the RRC reconfiguration complete message sent by the terminal device, the target network device executes step 1103.

1104. The source network device sends the second PDCP SDU to the target network device. Correspondingly, the target network device receives the second PDCP SDU. The second PDCP SDU may include one PDCP SDU or include multiple PDCP SDUs. Specifically, for the second PDCP SDU, reference may be made to the description in 1003 in FIG. 10, which is not repeated here for brevity.

It should be noted that the order of execution of step 1103 and step 1104 is not limited. For example, step 1103 can be executed before step 1104, or step 1103 can be executed after step 1104, or step 1103 and step 1104 can be executed simultaneously .

1105. The target network device uses its own corresponding parameters to compare the second PDCP SDU and the third PDCP SDU (the third PDCP SDU is the PDCP SDU remaining after the fourth PDCP SDU is removed from the first PDCP SDU, and the third PDCP SDU may include One PDCP SDU or multiple PDCP SDUs) are processed. As an example, the target network device uses its own corresponding header compression context to perform header compression on the second PDCP SDU, and uses its own key to encrypt the second PDCP SDU to obtain the second PDCP PDU. Similarly, the target network device Use its own corresponding header compression context to perform header compression on the third PDCP SDU, and use its corresponding key to encrypt the third PDCP SDU and other processing to obtain the third PDCP PDU. It should be noted that the target network device may first perform header compression and encryption on the second PDCP SDU, and then perform header compression and encryption on the third PDCP SDU.

Exemplarily, after the target network device sends a part of the first PDCP SDU (that is, the fourth PDCP SDU) to the terminal device, it receives the second PDCP SDU from the source network device. In this case, the target network device may first perform the second PDCP SDU. The SDU performs header compression, decryption, and other processing. After that, the target network device continues to compress and decrypt the PDCP SDU that is not sent in the first PDCP SDU (that is, the third PDCP SDU, which is the PDCP SDU in the first PDCP SDU that has not been sent to the terminal device). Wait for processing.

In this case, the target network device can re-allocate the PDCP SN (may be called the third PDCP SN) for the third PDCP SDU on the basis of the PDCP SN allocated by the source network device for the third PDCP SDU. Based on the PDCP SN allocated for the second PDCP SDU, the device re-allocates the PDCP SN (may be referred to as the second PDCP SN) for the second PDCP SDU. Wherein, the third PDCP SN has a first offset value relative to the PDCP SN allocated by the source network device to the third PDCP SDU, and the second PDCP SN allocates the second PDCP SDU to the source network device The PDCP SN has a second offset value.

In some possible implementation manners, the first offset value is determined according to the number of second PDCP SDUs that are not successfully sent to the terminal device, that is, the first offset value is equal to the second PDCP that is not successfully sent to the terminal device. The number of SDUs. The second offset value is based on the first offset value, and before the target network device receives the second PDCP SDU, the target network device has already checked some of the SDUs in the first PDCP SDU (that is, the fourth PDCP SDU). ) The number of PDCP SDUs (that is, the number of fourth PDCP SDUs, for example, the value is P) subjected to the corresponding processing of the PDCP layer is determined, that is, the second offset value is equal to the first offset value plus P. Alternatively, the second offset value is based on the first offset value and the number of fourth PDCP PDUs that have been sent to the terminal device before the target network device receives the second PDCP SDU (for example, , The value is determined by P), that is, the second offset value is equal to the first offset value plus P.

Take, for example, that the PDCP SN corresponding to the first PDCP SDU is 101-120, and the PDCP SN corresponding to the second PDCP SDU is 90-100 as an example. When the target network device performs header compression and encryption on the PDCP SDUs whose PDCP SN is 101-110 (that is, the fourth PDCP SDU), it receives PDCP SDUs whose PDCP SN is 90-100 from the source network device. At this time, the target network device may not continue to process the PDCP SDUs (that is, the third PDCP SDU) whose PDCP SN is 111-120, but instead process the PDCP SDUs (that is, the second PDCP SDU) whose PDCP SN is 90-100. Header compression, encryption and other processing. At this time, the target network device can interpret "PDCP SDUs with PDCP SN 90-100 respectively" as (pretend to be) "PDCP SN' (ie, the second PDCP SN) PDCP SDUs with 111-121 respectively". Then, the target network device performs header compression and decryption on the PDCP SDUs assigned by the source network device with SN 111-120 (that is, the third PDCP SDU). Correspondingly, the target network device sets the "PDCP assigned by the source network device" "PDCP SDUs with SN 111-120 respectively" is understood as (pretending to be) "PDCP SN' (that is, the third PDCP SN) is PDCP SDUs with 122-131 respectively". If the subsequent target network device also receives the PDCP SDU, the new PDCP SDU with the subsequent PDCP SN of Z will be processed according to the PDCP SN' of (Z+11). Here, "11" represents the number of second PDCP SDUs.

In a possible implementation, in addition to "PDCP SN", the packet header of PDCP PDU may also include "PDCP SN'" (ie virtual serial number), so that the terminal device can determine the PDCP PDU corresponding to the PDCP packet header. PDCP SN (that is, the actual serial number), so as to correctly receive DL data from the target network device.

1106. The target network device sends sixth indication information to the terminal device, where the sixth indication information is used to indicate that the third PDCP SN corresponding to the third PDCP PDU received by the terminal device from the target network device and the source network device are third The mapping relationship between the PDCP SN allocated by the PDCP SDU, and the sixth indication information may also be used to indicate that the second PDCP SN corresponding to the second PDCP PDU received by the terminal device from the target network device and the source network device are The mapping relationship between the PDCP SNs allocated by the second PDCP SDU.

In other words, the sixth indication information can indicate how the target network device processes the third PDCP SDU and the second PDCP SDU. For example, the sixth indication information may include the first offset value and the second offset value. At this time, for the second PDCP PDU received from the target network device (the second PDCP PDU is generated after the target network device uses its own parameters to process the second PDCP SDU), PDCP SN' is equal to PDCP SN plus the first Two offset value. For the third PDCP PDU received from the target network device (the third PDCP PDU is generated after the target network device uses its own parameters to process the third PDCP SDU), PDCP SN' is equal to PDCP SN plus the first offset value. In this way, the terminal device can correctly receive the downlink data packet received from the target network device according to the sixth indication information.

Alternatively, the sixth indication information may include the PDCP SN' allocated by the target network device and the PDCP SN allocated by the corresponding source network device. For example, the sixth indication information may include at least one PDCP SN in the third PDCP SN and the associated PDCP SN. At least one PDCP SN in the PDCP SN allocated by the source network device corresponding to at least one PDCP SN in the third PDCP SN, and the sixth indication information further includes at least one PDCP SN in the second PDCP SN SN and at least one PDCP SN in the PDCP SN allocated by the source network device corresponding to at least one PDCP SN in the second PDCP SN, or the sixth indication information may be expressed in other forms, this embodiment There is no restriction on this.

In some possible implementation manners, the target network device may also send the sixth indication information to the source network device, and the source network device sends the sixth indication information to the terminal device, which is not limited in this embodiment of the application.

In some possible embodiments, the foregoing first offset value and second offset value may be of bearing granularity, that is, different bearers may have respective corresponding first offset values and second offset values. Alternatively, the sixth indication information may be of bearing granularity. The embodiments of this application do not limit this. Specifically, the carrying granularity of the sixth indication information is similar to the carrying granularity of the second indication information, and reference may be made to the description of the second indication information above. For brevity, details are not repeated here.

1107. The target network device sends the third PDCP PDU (the third PDCP PDU is generated after the target network device uses its own parameters to process the third PDCP SDU) and the second PDCP PDU to the terminal device. Correspondingly, the terminal device receives the third PDCP PDU and the second PDU, and processes the third PDCP PDU and the second PDCP PDU according to the sixth indication information and using the parameters corresponding to the target network device.

As an example, the terminal device learns the mapping relationship between PDCP SN' and PDCP SN corresponding to the second PDCP PDU received from the target network device according to the sixth indication information, and learns that the second PDCP PDU received from the target network device is mapped 3. The mapping relationship between PDCP SN' and PDCP SN corresponding to PDCP PDU. The terminal device can use the key corresponding to the target network device to decrypt the third PDCP PDU and the second PDCP PDU according to at least one of PDCP SN and PDCP SN'; according to at least one of PDCP SN and PDCP SN', use the target The header decompression context corresponding to the network device decompresses the third PDCP PDU and the second PDCP PDU. Exemplarily, the target network device may first process the second PDCP SDU (such as header compression, encryption, etc.), and then process the third PDCP SDU (such as header compression, encryption, etc.). Correspondingly, the terminal device may first process the second PDCP PDU (such as decryption, header decompression, etc.), and then process the third PDCP PDU (such as decryption, header decompression, etc.).

Therefore, in the embodiment of the present application, the target network device sends the unsuccessfully sent PDCP SDU(s) forwarded by the source network device to the terminal device after special processing. For example, the target network device can assign a virtual PDCP SDU(s) forwarded by the source network device to PDCP SDU(s) that are not successfully sent to the terminal device, and PDCP SDU(s) that the target network device has not yet sent to the terminal device, The corresponding processing method (for example, the mapping relationship between the actual PDCP SN and the virtual PDCP SN'; or, for example, the first offset value and the second offset value) is notified to the terminal device, so that the terminal device can correctly respond to the slave The PDCP PDUs received by the target network device are processed, so that the terminal device can correctly receive DL data.

For uplink data transmission, in a possible implementation manner, after the terminal device successfully accesses the target cell, or after the terminal device sends an RRC reconfiguration complete message to the target network device, the uplink data transmission can be converted. In other words, before the terminal device successfully connects to the target network device, the terminal device only performs uplink data transmission with the source network device. After the terminal device successfully connects to the target network device, the terminal device only performs uplink data with the target network device. transmission. As an example, when the terminal device receives a random access response (RAR) message sent by the target network device, it means that the terminal device successfully accesses the target cell.

Specifically, for the uplink data carried by a certain UL, before the uplink data transmission conversion, the terminal device uses the header compression context corresponding to the source network device to perform header compression, and the key corresponding to the source network device is encrypted and sent to Source network device. As an example, the terminal device may send UL data packets with PDCP and SN of 0-50 to the source network device. Once the terminal device performs the UL data transmission conversion, for the uplink data carried by the UL, the terminal device uses the header compression context corresponding to the target network device to perform header compression, and the key corresponding to the target network device is encrypted and sent to the target network equipment. As an example, the terminal device may send the subsequent UL data packets of the PDCP SN starting from 51 to the target network device.

However, after the UL data transmission conversion, the terminal device finds that some of the UL data packets previously sent to the source network device have not been successfully received by the source network device. As an example, suppose the terminal device, after sending a UL data packet with a PDCP SN of 60 to the target network device, learns that the UL data packet with a PDCP SN of 45 sent to the source network device has not been successfully received by the source network device. For example, the terminal device receives the PDCP status report corresponding to the UL data packet sent by the terminal device to the source network device from the network device side (such as the source network device or the target network device), and finds that the UL data packet with a PDCP SN of 45 is not successfully sent To the source network device. It should be noted that here, a data packet is not successfully received as an example. In the embodiment of this application, there may be multiple data packets that are not successfully received, and the PDCP SN corresponding to the multiple data packets may be continuous. , It may also be non-continuous, which is not limited in the embodiment of the present application.

The embodiment of the application provides a data transmission method. The terminal device can process the UL data packet that is not successfully sent to the source network device using the parameters corresponding to the source network device (for example, using the header compression context corresponding to the source network device). After header compression, the key corresponding to the source network device is encrypted, and then sent to the target network device, and then the target network device directly forwards the data packet received from the source network device to the source network device, and the source network device Use its own corresponding parameters for processing (for example, use the header decompression context corresponding to the source network device to perform header decompression, and the key corresponding to the source network device to decrypt it), so that the terminal device can correctly transmit UL data.

FIG. 12 is a schematic flowchart of a data transmission method 1200 from the perspective of device interaction. It should be understood that FIG. 12 shows the steps or operations of the data transmission method, but these steps or operations are only examples, and the embodiment of the present application may also perform other operations or variations of each operation in FIG. 12. In addition, the various steps in FIG. 12 may be performed in a different order from that presented in FIG. 12, and it is possible that not all the operations in FIG. 12 are to be performed. As shown in FIG. 12, the admission control method may include steps 1201 to 1206.

1201. The terminal device sends an RRC reconfiguration complete message to the target network device. At this time, the terminal device performs UL data transmission conversion, that is, the terminal device switches from PUSCH transmission with the source network device to PUSCH transmission with the target network device. That is, the terminal device maintains PUSCH transmission with the source network device before sending the RRC reconfiguration complete message, and starts PUSCH transmission with the target network device after sending the RRC reconfiguration complete message. As an example, the time when the RRC reconfiguration complete message is sent is used as the time when the terminal device performs UL data transmission conversion, and the time when the terminal device receives the earliest UL grant sent by the target network device can also be used as the terminal device to perform UL data transmission conversion. Time, or other, this embodiment does not limit this.

As an example, before step 1201, for the uplink data, the terminal device uses the parameters corresponding to the source network device to process the PDCP SDU, and sends the PDCP PDU obtained after the processing to the source network device. In a possible way, the moment when the terminal device completes the random access process is used as the moment when the terminal device performs UL data transmission conversion. For example, the terminal device performs UL after receiving the random access response RAR message sent by the target network device. Data transmission conversion, or the time when the terminal device receives the random access response message is taken as the time when the terminal device performs UL data transmission conversion. After step 1201, for subsequent UL data packets, the terminal device uses the parameters corresponding to the target network device to process the PDCP SDU, and sends the PDCP PDU obtained after the processing to the target network device.

1202. The terminal device fails to send an uplink data packet to the source network device. That is to say, after step 1201, that is, when the terminal device has been converted from PUSCH with the source network device to PUSCH transmission with the target network device, 1202 occurs, that is, the terminal device discovers that the terminal device has switched to the source before the UL data transmission conversion time. The uplink data packet sent by the network device fails (the uplink data packet failure here can be understood as PDCP SDU failure, or it can also be understood as PDCP PDU failure. For the following description, collectively referred to as PDCP PDU failure).

After the PUSCH conversion of the terminal device, it is found that the PDCP PDU sent to the source network device before the PUSCH conversion fails, for example, the fifth PDCP PDU fails. The fifth PDCP PDU may include one PDCP PDU or include multiple PDCP PDUs. Among them, the fifth PDCP PDU is generated after the terminal device uses the parameters corresponding to the source network device to process the fifth PDCP SDU. For example, the terminal device uses the header compression context corresponding to the source network device, the key corresponding to the source network device, etc. Perform header compression and decryption on the fifth PDCP SDU.

1203. The terminal device sends the uplink data packet whose transmission failed in step 1202, that is, the fifth PDCP PDU, to the target network device. Obviously, in addition to the fifth PDCP PDU, the terminal device will also send other PDCP PDUs to the target network device. For example, the terminal device will also send a new packet to the target network device.

Optionally, the header of the fifth PDCP PDU carries eighth indication information, which is used to indicate that the fifth PDCP PDU is a PDCP PDU that the terminal device has not successfully sent to the source network device. The eighth indication information may be a binary value (such as a bit), or a Boolean value, or other manifestations, and is not limited.

In some possible implementation manners, an indication field may be added to the header of the fifth PDCP PDU, and the indication field is used to indicate whether the PDCP PDU needs to be forwarded to the source network device. As an example, the indication field can be a bit. When the bit is "0", it means that the corresponding data packet needs to be forwarded by the target network device to the source network device, and the source network device uses the corresponding parameters to process the data packet ; When the bit is "1", it means that the corresponding data packet does not need to be forwarded by the target network device to the source network device. Or vice versa, which is not limited in the embodiment of the present application. Or, the indication field can be a Boolean value. When the Boolean value is "true", it means that the corresponding data packet needs to be forwarded to the source network device by the target network device, and the source network device will process the data packet; when the Boolean value is "true" When the value is "false", it means that the corresponding data packet does not need to be forwarded by the target network device to the source network device. Or vice versa, which is not limited in the embodiment of the present application.

1204. Optionally, the terminal device sends seventh indication information to the target network device, which is used to indicate that the fifth PDCP PDU is uplink data that failed to be successfully sent to the source network device. In an example, the seventh indication information is used to indicate the PDCP SN corresponding to the fifth PDCP PDU, for example, the seventh indication information includes the PDCP SN corresponding to the fifth PDCP PDU, respectively. Correspondingly, the target network device receives the seventh indication information, and determines that the PDCP PDU (that is, the fifth PDCP PDU) indicated by the seventh indication information needs to be forwarded to the source network device.

In other possible descriptions, the seventh indication information may also be used to indicate to the target network device which PDCP PDUs need to be forwarded by the target network device to the source network device, which is not limited in this embodiment of the application.

In an optional embodiment of the present application, if the header of the fifth PDCP PDU carries indication information, step 1204 may not be performed.

As an example, the terminal device may send a message to the target network device, and the message may include the seventh indication information. As an example, at this time, the seventh indication information may include the PDCP SN corresponding to the fifth PDCP PDU that the terminal device failed to successfully send to the source network device. Here, the PDCP SN included in the seventh indication information may be continuous or non-continuous, depending on the PDCP PDU that the terminal device failed to successfully send to the source network device in step 1203.

Optionally, the foregoing message may be an RRC message, or a layer 2 message, or a physical layer message, which is not limited in the embodiment of the present application. The layer 2 message may be, for example, PDCP control PDU, MAC CE, etc., and the physical layer message may be DCI.

In some possible embodiments, the PDCP SN indicated by the seventh indication information may be of bearer granularity, that is, different bearers may have their own corresponding PDCP SNs. Or, the seventh indication information may be of bearing granularity. The embodiments of this application do not limit this. Specifically, the carrying granularity of the seventh indication information is similar to the carrying granularity of the second indication information. Refer to the above description of the second indication information. For brevity, details are not repeated here.

It should be noted that the order of execution of step 1203 and step 1204 (if executed) is not limited. For example, step 1203 can be executed before step 1204, or step 1203 can be executed after step 1204, or, step 1203 and step 1203 can be executed before step 1204. Step 1204 can be performed at the same time.

1205. The target network device sends a fifth PDCP PDU to the source network device. Correspondingly, the source network device receives the fifth PDCP PDU from the target network device.

For the PDCP PDU received by the target network device from the terminal device, if the PDCP SN corresponding to the PDCP PDU is included in the PDCP SN indicated by the seventh indication information, or the packet header of the PDCP PDU includes a packet used to indicate that the PDCP PDU is a terminal The PDCP PDU indication information (such as the eighth indication information) that the device did not successfully send to the source network device, that is, the PDCP PDU is the fifth PDCP PDU, the target network device forwards the PDCP PDU to the source network device, and the source network device Use its own header decompression context for header decompression, and use its own key for decryption and other processing. The source network device can send the processed data packet to the UPF, or forward it to the target network device, and the target network device can send it to the UPF.

If the PDCP SN corresponding to the PDCP PDU received by the target network device from the terminal device is not included in the PDCP SN indicated by the seventh indication information, or the packet header of the PDCP PDU contains a header indicating that the PDCP PDU does not need to be forwarded to the source The indication information of the network device, or the packet header of the PDCP PDU does not contain indication information indicating that the PDCP PDU is a PDCP PDU that the terminal device has not successfully sent to the source network device, then the target network device uses its own corresponding header to decompress The context decompresses the PDCP PDU received from the terminal device, and uses the key corresponding to the target network device to decrypt the PDCP PDU received from the terminal device. The target network device can send the processed data packet to the UPF.

As an example, after the terminal device sends a UL data packet with a PDCP SN of 60 to the target network device, it learns that the UL data packet with a PDCP SN of 45 is not successfully received by the source network device. At this time, for a PDCP SDU with a PDCP SN of 45, the terminal device uses the header compression context corresponding to the source network device to perform header compression, uses the key corresponding to the source network device to perform encryption and other processing, and then generates a PDCP PDU with a PDCP SN of 45.

Then, the terminal device sends the PDCP PDU with a PDCP SN of 45 (that is, the fifth PDCP PDU) to the target network device, and instructs the target network device to forward the PDCP PDU to the source network device. In a possible way, the packet header of the PDCP PDU with the PDCP SN of 45 includes indication information for instructing the target network device to forward the PDCP PDU with the PDCP SN of 45 to the source network device. In a possible manner, the terminal device may send seventh indication information to the network device. The seventh indication information includes 45, which is used to instruct the target network device to forward the PDCP PDU with the PDCP SN of 45 to the source network device.

After the target network device receives the PDCP PDU with a PDCP SN of 45, it forwards it to the source network device according to the indication information on the packet header or the seventh indication information. After receiving the PDCP PDU, the source network device uses the header decompression context corresponding to the source network device to perform header decompression, and uses the key corresponding to the source network device to perform decryption and other processing to obtain the PDCP SDU with a PDCP SN of 45. Then, the source network device may send the UL data packet with the PDCP SN of 45 to the UPF. Alternatively, the source network device may send the UL data packet with a PDCP SN of 45 to the target network device, and the target network device sends it to the UPF.

Therefore, in the embodiment of the present application, the terminal device may process the UL data packet that was not successfully sent to the source network device using the parameters corresponding to the source network device, for example, use the header compression context corresponding to the source network device to perform header compression , The key corresponding to the source network device is encrypted and sent to the target network device, and instructs the target network device to forward these data packets to the source network device, and the source network device uses its own header decompression context to perform header decompression , Its own key is decrypted and other processing, so that the terminal device can correctly send UL data, and the network device side can correctly receive UL data.

It can be understood that, in the foregoing method embodiments, the method implemented by the terminal device can also be implemented by a component (such as a chip or circuit, etc.) that can be configured in the terminal device, and is implemented by a network device (source network device or target network device). The implementation method can also be implemented by a component (for example, a chip or a circuit, etc.) that can be configured in a network device.

It can be understood that, in the various embodiments of the present application, the interaction between the network device (the source network device or the target network device) and the terminal device can also be applied to the interaction between the CU and the terminal device, or the DU and the terminal device. The interaction between. It can be understood that the interaction mechanism between the network device and the terminal device in the various embodiments of the present application can be appropriately modified to adapt to the interaction between the CU or DU and the terminal device.

According to the foregoing method, FIG. 13 is a schematic diagram of a wireless communication apparatus 1300 provided in an embodiment of this application.

In some embodiments, the apparatus 1400 may be a terminal device, or a chip or circuit, for example, a chip or circuit that can be provided in a terminal device.

In some embodiments, the apparatus 1400 may be a source network device, or a chip or circuit, for example, a chip or circuit that can be provided in the source network device.

In some embodiments, the apparatus 1400 may be a target network device, or a chip or circuit, for example, a chip or circuit that can be installed in the target network device.

In a possible manner, the apparatus 1300 may include a processing unit 1310 (that is, an example of at least one processor) and a transceiver unit 1330. In some possible implementations, the transceiver unit 1330 may include a receiving unit and a sending unit.

Optionally, the transceiver unit 1330 may be implemented by a transceiver or a transceiver-related circuit or interface circuit.

Optionally, the device may further include a storage unit 1320. In a possible manner, the storage unit 1320 is used to store information such as instructions and/or data. The storage unit 1320 may be realized by a memory.

In some possible designs, the processing unit 1310 is configured to execute information such as instructions and/or data stored in the storage unit 1320, so that the apparatus 1300 implements the steps performed by the terminal device in the foregoing method. Alternatively, the processing unit 1310 may be used to call the data of the storage unit 1320, so that the apparatus 1300 implements the steps performed by the terminal device in the foregoing method.

In some possible designs, the processing unit 1310 is configured to execute information such as instructions and/or data stored in the storage unit 1320, so that the apparatus 1300 implements the steps performed by the source network device in the foregoing method. Alternatively, the processing unit 1310 may be used to call the data of the storage unit 1320, so that the apparatus 1300 implements the steps performed by the source network device in the foregoing method.

In some possible designs, the processing unit 1310 is configured to execute information such as instructions and/or data stored in the storage unit 1320, so that the apparatus 1300 implements the steps performed by the target network device in the foregoing method. Alternatively, the processing unit 1310 may be used to call the data of the storage unit 1320, so that the apparatus 1300 implements the steps performed by the target network device in the foregoing method.

For example, the processing unit 1310, the storage unit 1320, and the transceiver unit 1330 can communicate with each other through internal connection paths to transfer control and/or data signals. For example, the storage unit 1320 is used to store a computer program, and the processing unit 1310 can be used to call and run the calculation program from the storage unit 1320 to control the transceiver unit 1330 to receive and/or send signals to complete the above method. Steps for terminal equipment. The storage unit 1320 may be integrated in the processing unit 1310, or may be provided separately from the processing unit 1310.

Optionally, if the apparatus 1300 is a communication device (for example, a terminal device, or a source network device, or a target network device), the transceiver unit 1330 includes a receiver and a transmitter. Among them, the receiver and the transmitter may be the same or different physical entities. When they are the same physical entity, they can be collectively referred to as transceivers.

Optionally, if the device 1300 is a chip or a circuit, the transceiver unit 1330 includes an input interface and an output interface.

As an implementation manner, the function of the transceiver unit 1330 may be implemented by a transceiver circuit or a dedicated chip for transceiver. The processing unit 1310 may be implemented by a dedicated processing chip, a processing circuit, a processing unit, or a general-purpose chip.

As another implementation manner, a general-purpose computer may be considered to implement the communication device (for example, a terminal device, or a source network device, or a target network device) provided in the embodiments of the present application. That is, the program code for realizing the functions of the processing unit 1310 and the transceiver unit 1330 is stored in the storage unit 1320. The general processing unit implements the functions of the processing unit 1310 and the transceiver unit 1330 by executing the code in the storage unit 1320.

In some embodiments, the apparatus 1300 may be a terminal device, or a chip or circuit provided in the terminal device.

When the apparatus 1300 may be a terminal device, or a chip or circuit provided in the terminal device, in some optional embodiments, the transceiver unit 1330 is configured to receive first indication information, and the first indication information is used to indicate that the terminal device is operated by The physical uplink shared channel PUSCH transmission with the source network device is converted to PUSCH transmission with the target network device, wherein the terminal device maintains the PUSCH transmission with the source network device before receiving the first indication information, so The terminal device starts to perform PUSCH transmission with the target network device after receiving the first indication information.

The processing unit 1310 is configured to switch from PUSCH transmission with the source network device to PUSCH transmission with the target network device according to the first indication information.

Optionally, the transceiving unit 1330 is further configured to receive second indication information, where the second indication information is used to indicate that the terminal device needs to transmit to the target network device after converting to PUSCH transmission with the target network device. The minimum data convergence protocol PDCP serial number SN of the uplink data packet sent by the network device.

Optionally, the second indication information includes the PDCP SN of the first uplink data packet sent by the terminal device to the target network device.

Optionally, the second indication information includes a PDCP status report, and the PDCP status report is used to obtain the minimum PDCP SN of the uplink data packet that needs to be sent to the target network device.

Optionally, the PDCP SN is of bearer granularity.

Optionally, the transceiving unit 1330 is further configured to receive uplink authorization information, where the uplink authorization information is allocated by the target network device to the terminal device and used for PUSCH transmission between the terminal device and the target network device .

Optionally, the transceiver unit 1330 is further configured to send an RRC reconfiguration complete message to the target network device, or receive a random access response RAR message sent by the target network device.

When the apparatus 1300 may be a terminal device, or a chip or circuit provided in the terminal device, in some optional embodiments, the transceiver unit 1330 is used for the fourth indication information, and the fourth indication information is used for indicating the connection with at least one packet At least one PDCP sequence number SN corresponding to the data convergence protocol PDCP protocol data unit PDU one-to-one, and the at least one PDCP PDU is a PDCP PDU that the source network device fails to send to the terminal device.

The transceiving unit 1330 is further configured to receive the at least one PDCP PDU from a target network device, and process the at least one PDCP PDU using parameters corresponding to the source network device, wherein the at least one PDCP PDU received from the target network device A PDCP PDU is a PDCP PDU from the source network device.

When the apparatus 1300 may be a terminal device, or a chip or circuit provided in a terminal device, in some optional embodiments, the transceiver unit 1330 is further configured to obtain sixth indication information, and the sixth indication information is used to indicate the terminal The mapping relationship between the third PDCP SN corresponding to the third PDCP PDU received by the device from the target network device and the PDCP SN allocated by the source network device for the third PDCP SDU, and the second received from the target network device The mapping relationship between the second PDCP SN corresponding to the PDCP PDU and the PDCP SN allocated by the source network device for the second PDCP SDU, where the third PDCP PDU corresponds to the target network device using the target network device The parameters of is generated after processing the third PDCP SDU from the source network device, and the third PDCP SN is allocated by the target network device, and the second PDCP PDU is used by the target network device The parameters corresponding to the target network device are generated after processing the second PDCP SDU from the source network device, and the second PDCP SN is allocated by the target network device, and the third PDCP SDU is Before the target network device receives the second PDCP SDU, the target network device in the first PDCP SDU sent by the source network device to the target network device has not used the parameters corresponding to the target network device The PDCP SDU to be processed, and the second PDCP SDU is a PDCP SDU that the terminal device does not successfully receive from the source network device.

The transceiver unit 1330 is further configured to receive the third PDCP PDU and the second PDCP PDU from the target network device.

The processing unit 1310 is configured to process the third PDCP PDU and the second PDCP PDU using parameters corresponding to the target network device according to the sixth indication information.

Optionally, the processing unit 1310 is specifically configured to: obtain, according to the sixth indication information, the third PDCP SN corresponding to the third PDCP PDU received by the terminal device from the target network device and that the source network device is the third PDCP The mapping relationship between the PDCP SN allocated by the SDU, and the mapping between the second PDCP SN corresponding to the second PDCP PDU received from the target network device and the PDCP SN allocated by the source network device for the second PDCP SDU relationship.

Then, according to the PDCP SN allocated by the source network device for the second PDCP SDU and the second PDCP SN, the parameters corresponding to the target network device are used to process the second PDCP PDU.

According to the PDCP SN allocated by the source network device to the third PDCP SDU and the third PDCP SN, use the parameters corresponding to the target network device to process the third PDCP PDU.

When the device 1300 is configured in or is a terminal device, each module or unit in the device 1300 can be used to execute various actions or processing procedures performed by the terminal device in the foregoing method. Here, in order to avoid redundant description, detailed descriptions are omitted.

In some embodiments, the apparatus 1300 may be a network device, or a chip or circuit provided in the network device. The network device can be a source network device or a target network device.

When the apparatus 1300 is a network device, or a chip or circuit provided in the network device, in some optional embodiments, the processing unit 1310 is configured to obtain first indication information, and the first indication information is used to indicate the The terminal device converts the physical uplink shared channel PUSCH transmission with the source network device to PUSCH transmission with the target network device.

The transceiver unit 1330 is configured to send the first instruction information to the terminal device, where the terminal device maintains PUSCH transmission with the source network device before receiving the first instruction information, and the terminal device After receiving the first indication information, the device starts to perform PUSCH transmission with the target network device.

Optionally, the processing unit 1310 is further configured to determine second indication information, where the second indication information is used to indicate that the terminal device needs to transmit to the target network device after converting to PUSCH transmission with the target network device. The minimum data convergence protocol PDCP serial number SN of the uplink data packet sent by the network device;

The transceiving unit 1330 is further configured to send the second indication information to the terminal device.

Optionally, the PDCP SN is of bearer granularity.

Optionally, the processing unit 1310 is further configured to determine uplink authorization information, and the sending unit is further configured to send the uplink authorization information to the terminal device, where the uplink authorization information is allocated by the target network device to all The terminal device is used for PUSCH transmission between the terminal device and the target network device.

Optionally, the apparatus 1300 is the target network device or a chip in the target network device, and the transceiving unit 1330 is further configured to send third instruction information to the source network device, and the third instruction information It is used to indicate to the source network device that the terminal device successfully switches to the target network device.

Optionally, the transceiving unit 1330 is further configured to receive a PDCP status report from the source network device, where the PDCP status report is used to obtain the minimum number of uplink data packets of the uplink data that needs to be sent to the target network device. PDCP SN.

When the device 1300 is configured in or is the target network device, each module or unit in the device 1300 can be used to perform various actions or processing procedures performed by the target network device in the above method. Here, in order to avoid repetition, the details are omitted. Description.

When the apparatus 1300 is the source network device or a chip in the source network device, the transceiving unit 1330 is further configured to receive third instruction information sent by the target network device, and the third instruction information is used for Indicating to the source network device that the terminal device successfully switches to the target network device.

Optionally, the transceiver unit 1330 is further configured to receive uplink authorization information sent by the target network device, where the uplink authorization information is allocated to the terminal device by the target network device and used for the terminal device and the target network The device performs PUSCH transmission.

When the device 1300 is configured in or is the source network device, each module or unit in the device 1300 can be used to perform various actions or processing procedures performed by the source network device in the foregoing method. Here, in order to avoid repetition, the details are omitted. Description.

When the device 1300 is a target network device, or a chip or circuit set in the network device, in some optional embodiments, the transceiver unit 1330 is configured to receive at least one PDCP PDU from the source network device, the at least one PDCP PDU It is the PDCP PDU that the source network device did not successfully send to the terminal device.

The transceiver unit 1330 is further configured to receive fourth indication information from the source network device, where the fourth indication information is used to indicate the at least one PDCP sequence number SN corresponding to the at least one PDCP PDU in a one-to-one manner.

The transceiver unit 1330 is further configured to send the fourth indication information and the at least one PDCP PDU to the terminal device.

When the apparatus 1300 is a target network device, or a chip or circuit set in the network device, in some optional embodiments, the transceiver unit 1330 is configured to receive the first PDCP SDU from the source network device, and the source network device PDCP SN allocated for the first PDCP SDU.

The transceiving unit 1330 is further configured to receive a second PDCP SDU from the source network device, and the PDCP SN allocated by the source network device for the second PDCP SDU, and the second PDCP SDU is not from the terminal device The PDCP SDU successfully received by the source network device.

The transceiving unit 1330 is further configured to send a third PDCP PDU and a second PDCP PDU to the terminal device, where the third PDCP PDU refers to the target network device using the parameters corresponding to the target network device to compare the third PDCP The second PDCP PDU is generated after the SDU is processed, and the second PDCP PDU is generated after the target network device uses the parameters corresponding to the target network device to process the second PDCP SDU, and the third PDCP SDU is generated in the Before the target network device receives the second PDCP SDU, the target network device in the first PDCP SDU has not yet processed the PDCP SDU using the parameters corresponding to the target network device;

The transceiver unit 1330 is further configured to send sixth indication information, where the sixth indication information is used to indicate the third PDCP SN corresponding to the third PDCP PDU and the PDCP SN allocated by the source network device for the third PDCP SDU. And the mapping relationship between the second PDCP SN corresponding to the second PDCP PDU and the PDCP SN allocated by the source network device for the second PDCP SDU, where the second PDCP SN and the The third PDCP SN is allocated by the target network device.

When the apparatus 1300 is a source network device, or a chip or circuit set in the source network device, in some optional embodiments, the transceiver unit 1330 is configured to send at least one PDCP PDU to the target network device, and the at least one PDCP The PDU is a PDCP PDU that the source network device did not successfully send to the terminal device.

The transceiver unit 1330 is further configured to send fourth indication information to the terminal device or the target network device, where the fourth indication information is used to indicate at least one PDCP sequence number SN corresponding to the at least one PDCP PDU one-to-one .

When the apparatus 1300 is a source network device, or a chip or circuit set in the source network device, in some optional embodiments, the transceiver unit 1330 is configured to send the first PDCP SDU to the target network device, and the source network device PDCP SN allocated for the first PDCP SDU.

The transceiver unit 1330 is further configured to send a second PDCP SDU to the target network device, and the PDCP SN allocated by the source network device to the second PDCP SDU, and the second PDCP SDU is not slaved to the terminal device. The PDCP SDU successfully received by the source network device.

The transceiver unit 1330 is further configured to receive sixth indication information from the target network device, where the sixth indication information is used to indicate the third PDCP SN corresponding to the third PDCP PDU received by the terminal device from the target network device The mapping relationship with the PDCP SN allocated by the source network device for the third PDCP SDU, and the second PDCP SN corresponding to the second PDCP PDU received from the target network device and the source network device are the second The mapping relationship between the PDCP SN allocated by the PDCP SDU, where the third PDCP PDU is after the target network device uses the parameters corresponding to the target network device to process the third PDCP SDU from the source network device The third PDCP SN is generated and allocated by the target network device, and the second PDCP PDU is the target network device using the parameters corresponding to the target network device to compare the second PDCP SN from the source network device. SDU is generated after processing and the second PDCP SN is allocated by the target network device, and the third PDCP SDU is before the target network device receives the second PDCP SDU, the first PDCP SDU The PDCP SDU that the target network device in has not yet used the parameters corresponding to the target network device for processing.

The transceiver unit 1330 is further configured to send the sixth indication information to the terminal device.

For the concepts related to the technical solutions provided in the embodiments of the present application and related concepts, explanations, detailed descriptions, and other steps involved in the device 1300, please refer to the descriptions of these contents in the foregoing methods or other embodiments, which are not repeated here.

FIG. 14 is a schematic structural diagram of a terminal device 1400 provided by this application. The terminal device 1400 can execute the actions performed by the terminal device in the foregoing method embodiments.

For ease of description, FIG. 14 only shows the main components of the terminal device. As shown in FIG. 14, the terminal device 1400 includes a processor, a memory, a control circuit, an antenna, and an input and output device.

The processor is mainly used to process the communication protocol and communication data, and to control the entire terminal device, execute the software program, and process the data of the software program. For example, it is used to support the terminal device to execute the above-mentioned transmission precoding matrix instruction method embodiment. The described action. The memory is mainly used to store software programs and data, for example, to store the codebook described in the above embodiments. The control circuit is mainly used for the conversion of baseband signals and radio frequency signals and the processing of radio frequency signals. The control circuit and the antenna together can also be called a transceiver, which is mainly used to send and receive radio frequency signals in the form of electromagnetic waves. Input and output devices, such as touch screens, display screens, keyboards, etc., are mainly used to receive data input by users and output data to users.

When the terminal device is turned on, the processor can read the software program in the storage unit, interpret and execute the instructions of the software program, and process the data of the software program. When data needs to be sent wirelessly, the processor performs baseband processing on the data to be sent, and outputs the baseband signal to the radio frequency circuit. The radio frequency circuit performs radio frequency processing on the baseband signal and sends the radio frequency signal to the outside in the form of electromagnetic waves through the antenna. When data is sent to the terminal device, the radio frequency circuit receives the radio frequency signal through the antenna, converts the radio frequency signal into a baseband signal, and outputs the baseband signal to the processor, and the processor converts the baseband signal into data and processes the data.

Those skilled in the art can understand that, for ease of description, FIG. 14 only shows a memory and a processor. In an actual terminal device, there may be multiple processors and memories. The memory may also be referred to as a storage medium or a storage device, etc., which is not limited in the embodiment of the present application.

For example, the processor may include a baseband processor and a central processing unit. The baseband processor is mainly used to process communication protocols and communication data. The central processing unit is mainly used to control the entire terminal device, execute software programs, and process software programs. data. The processor in FIG. 14 integrates the functions of the baseband processor and the central processing unit. Those skilled in the art can understand that the baseband processor and the central processing unit may also be independent processors and are interconnected by technologies such as a bus. Those skilled in the art can understand that the terminal device may include multiple baseband processors to adapt to different network standards, the terminal device may include multiple central processors to enhance its processing capabilities, and the various components of the terminal device may be connected through various buses. The baseband processor may also be expressed as a baseband processing circuit or a baseband processing chip. The central processing unit can also be expressed as a central processing circuit or a central processing chip. The function of processing the communication protocol and the communication data may be built in the processor, or stored in the storage unit in the form of a software program, and the processor executes the software program to realize the baseband processing function.

Exemplarily, in the embodiment of the present application, the antenna and control circuit with the transceiving function can be regarded as the transceiving unit 1410 of the terminal device 1400, and the processor with the processing function can be regarded as the processing unit 1420 of the terminal device 1400. As shown in FIG. 14, the terminal device 1400 includes a transceiving unit 1410 and a processing unit 1420. The transceiving unit may also be referred to as a transceiver, a transceiver, a transceiving device, and so on. Optionally, the device for implementing the receiving function in the transceiving unit 1410 can be regarded as the receiving unit, and the device for implementing the sending function in the transceiving unit 1410 can be regarded as the sending unit, that is, the transceiving unit includes a receiving unit and a sending unit. Exemplarily, the receiving unit may also be called a receiver, a receiver, a receiving circuit, etc., and the sending unit may be called a transmitter, a transmitter, or a transmitting circuit, etc.

FIG. 15 is a schematic structural diagram of a network device 1500 provided by an embodiment of the application, which may be used to implement the function of an access device (for example, a primary base station or a secondary base station) in the foregoing method. The network device 1500 includes one or more radio frequency units, such as a remote radio unit (RRU) 1510 and one or more baseband units (BBU) (also referred to as digital units, digital units, DU) 1520. The RRU 1510 may be called a transceiver unit, a transceiver, a transceiver circuit, or a transceiver, etc., and it may include at least one antenna 1511 and a radio frequency unit 1512. The RRU 1510 part is mainly used for receiving and sending of radio frequency signals and conversion of radio frequency signals and baseband signals, for example, for sending the signaling messages described in the foregoing embodiments to terminal equipment. The BBU1520 part is mainly used for baseband processing, control of the base station, and so on. The RRU 1510 and the BBU 1520 may be physically set together, or may be physically separated, that is, a distributed base station.

The BBU 1520 is the control center of the base station, and may also be called a processing unit, which is mainly used to complete baseband processing functions, such as channel coding, multiplexing, modulation, and spreading. For example, the BBU (processing unit) 1320 may be used to control the base station 40 to execute the operation flow of the network device in the foregoing method embodiment.

In an example, the BBU 1520 may be composed of one or more single boards, and multiple single boards may jointly support a radio access network of a single access standard (such as an LTE system or a 5G system), and may also support different connections. Enter the standard wireless access network. The BBU 1520 further includes a memory 1521 and a processor 1522. The memory 1521 is used to store necessary instructions and data. For example, the memory 1521 stores the codebook in the above-mentioned embodiment and the like. The processor 1522 is used to control the base station to perform necessary actions, for example, used to control the base station to execute the operation procedure of the network device in the foregoing method embodiment. The memory 1521 and the processor 1522 may serve one or more single boards. In other words, the memory and the processor can be set separately on each board. It can also be that multiple boards share the same memory and processor. In addition, necessary circuits can be provided on each board.

In a possible implementation manner, with the development of system-on-chip (SoC) technology, all or part of the functions of part 1520 and part 1510 can be realized by SoC technology, for example, a base station function chip Realization, the base station function chip integrates a processor, a memory, an antenna interface and other devices, the program of the base station related functions is stored in the memory, and the processor executes the program to realize the related functions of the base station. Optionally, the base station function chip can also read a memory external to the chip to implement related functions of the base station.

It should be understood that the structure of the network device illustrated in FIG. 15 is only a possible form, and should not constitute any limitation in the embodiment of the present application. This application does not exclude the possibility of other types of base station structures that may appear in the future.

It should be understood that, in this embodiment of the application, the processor may be a central processing unit (central processing unit, CPU), and the processor may also be other general-purpose processors, digital signal processors (digital signal processors, DSP), and dedicated integration Circuit (application specific integrated circuit, ASIC), ready-made programmable gate array (field programmable gate array, FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or the processor may also be any conventional processor or the like.

It should also be understood that the memory in the embodiments of the present application may be volatile memory or non-volatile memory, or may include both volatile and non-volatile memory. Among them, the non-volatile memory can be read-only memory (ROM), programmable read-only memory (programmable ROM, PROM), erasable programmable read-only memory (erasable PROM, EPROM), and electrically available Erase programmable read-only memory (electrically EPROM, EEPROM) or flash memory. The volatile memory may be random access memory (RAM), which is used as an external cache. By way of exemplary but not restrictive description, many forms of random access memory (RAM) are available, such as static random access memory (static RAM, SRAM), dynamic random access memory (DRAM), and synchronous dynamic random access memory (DRAM). 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 connection dynamic random access memory Take memory (synchlink DRAM, SLDRAM) and direct memory bus random access memory (direct rambus RAM, DR RAM).

The foregoing embodiments may be implemented in whole or in part by software, hardware, firmware or any other combination. When implemented by software, the above-mentioned embodiments may be implemented in the form of a computer program product in whole or in part. The computer program product includes one or more computer instructions or computer programs. When the computer instructions or computer programs are loaded or executed on the computer, the processes or functions described in the embodiments of the present application are generated in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. The computer instructions may be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions may be transmitted from a website, computer, server, or data center. Transmission to another website, computer, server or data center via wired (such as infrared, wireless, microwave, etc.). 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 or a data center that includes one or more sets of available media. The usable medium may be a magnetic medium (for example, a floppy disk, a hard disk, a magnetic tape), an optical medium (for example, a DVD), or a semiconductor medium. The semiconductor medium may be a solid state drive.

The embodiments of the present application also provide a computer-readable medium on which a computer program is stored, and when the computer program is executed by a computer, the steps performed by the terminal device in any of the above embodiments or the steps performed by the target network device are implemented. Or the steps performed by the source network device.

The embodiments of the present application also provide a computer program product that, when executed by a computer, implements the steps performed by the terminal device in any of the above embodiments, or the steps performed by the target network device, or the steps performed by the source network device .

According to the method provided in the embodiment of the present application, the embodiment of the present application also provides a communication system, which includes the aforementioned source network device, target network device, and terminal device.

The embodiment of the present application also provides a system chip, which includes a communication unit and a processing unit. The processing unit may be a processor, for example. The communication unit may be, for example, a communication interface, an input/output interface, a pin or a circuit, or the like. The processing unit can execute computer instructions to make the chip in the communication device execute the steps performed by the terminal device provided in the embodiments of the present application, or the steps performed by the target network device, or the steps performed by the source network device.

Optionally, the computer instructions are stored in a storage unit.

The various embodiments in this application can be used independently or in combination, which is not limited here. For example, the uplink data transmission method and the downlink data transmission method provided in the embodiments of the present application can be used independently or in combination, and both fall within the protection scope of the embodiments of the present application.

In addition, various aspects or features of the present application can be implemented as methods, devices, or products using standard programming and/or engineering techniques. The term "article of manufacture" used in this application encompasses a computer program accessible from any computer-readable device, carrier, or medium. For example, computer-readable media may include, but are not limited to: magnetic storage devices (for example, hard disks, floppy disks, or tapes, etc.), optical disks (for example, compact discs (CD), digital versatile discs (DVD)) Etc.), smart cards and flash memory devices (for example, erasable programmable read-only memory (EPROM), cards, sticks or key drives, etc.). In addition, various storage media described herein may represent one or more devices and/or other machine-readable media for storing information. The term "machine-readable medium" may include, but is not limited to, wireless channels and various other media capable of storing, containing, and/or carrying instructions and/or data.

It should be understood that "and/or" describes the association relationship of the associated objects, which means that there can be three kinds of relationships, for example, A and/or B, which can mean: A alone exists, A and B exist at the same time, and B alone exists. Happening. The character "/" generally indicates that the associated objects before and after are in an "or" relationship. "At least one" refers to one or more than one; "At least one of A and B", similar to "A and/or B", describes the association relationship of associated objects, indicating that there can be three relationships, for example, A and B At least one of them can mean: A alone exists, A and B exist at the same time, and B exists alone.

A person of ordinary skill in the art may realize that the units and algorithm steps of the examples described in combination with the embodiments disclosed herein can be implemented by electronic hardware or a combination of computer software and electronic hardware. Whether these functions are performed by hardware or software depends on the specific application and design constraint conditions of the technical solution. Professionals and technicians can use different methods for each specific application to implement the described functions, but such implementation should not be considered beyond the scope of this application.

Those skilled in the art can clearly understand that, for the convenience and conciseness of description, the specific working process of the system, device and unit described above can refer to the corresponding process in the foregoing method embodiment, which will not be repeated here.

In the several embodiments provided in this application, it should be understood that the disclosed system, device, and method may be implemented in other ways. For example, the device embodiments described above are merely illustrative, for example, the division of the units is only a logical function division, and there may be other divisions in actual implementation, for example, multiple units or components may be combined or It can be integrated into another system, or some features can be ignored or not implemented. In addition, the displayed or discussed mutual coupling or direct coupling or communication connection may be indirect coupling or communication connection through some interfaces, devices or units, and may be in electrical, mechanical or other forms.

The units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the objectives of the solutions of the embodiments.

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

If the function is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer readable storage medium. Based on this understanding, the technical solution of the present application essentially or the part that contributes to the existing technology or the part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including Several instructions are used to make a computer device (which may be a personal computer, a server, or a network device, etc.) execute all or part of the steps of the methods described in the various embodiments of the present application. The aforementioned storage media include: U disk, mobile hard disk, read-only memory (Read-Only Memory, ROM), random access memory (Random Access Memory, RAM), magnetic disk or optical disk and other media that can store program code .

The above are only specific implementations of this application, but the protection scope of this application is not limited to this. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed in this application. Should be covered within the scope of protection of this application. Therefore, the protection scope of this application should be subject to the protection scope of the claims.

Claims

A method of data transmission, characterized in that it comprises:

Receive first indication information, where the first indication information is used to indicate that the physical uplink shared channel PUSCH transmission with the source network device is converted to the PUSCH transmission with the target network device, wherein the terminal device before receiving the first indication information Maintaining PUSCH transmission with the source network device, and the terminal device starts PUSCH transmission with the target network device after receiving the first indication information;

According to the first indication information, the PUSCH transmission with the source network device is converted to the PUSCH transmission with the target network device.
The method according to claim 1, further comprising:

Receive second indication information, where the second indication information is used to indicate the minimum data convergence protocol PDCP sequence number SN of the uplink data packet that needs to be sent to the target network device after conversion to PUSCH transmission with the target network device .
The method according to claim 2, wherein the second indication information includes a minimum PDCP SN of an uplink data packet sent to the target network device.
The method according to claim 2, wherein the second indication information includes a PDCP status report, and the PDCP status report is used to obtain the minimum PDCP SN of the uplink data packet that needs to be sent to the target network device .
The method according to any one of claims 2-4, wherein the PDCP SN is of bearer granularity.
The method according to any one of claims 1-5, further comprising:

Receive uplink authorization information, where the uplink authorization information is allocated to a terminal device by the target network device and used for PUSCH transmission between the terminal device and the target network device.
The method according to any one of claims 1-6, wherein before the receiving the first indication information, the method further comprises:

Send an RRC reconfiguration complete message to the target network device, or receive a random access response RAR message sent by the target network device.
A method of data transmission, characterized in that it comprises:

Acquiring first indication information, where the first indication information is used to instruct the terminal device to switch from physical uplink shared channel PUSCH transmission with the source network device to PUSCH transmission with the target network device;

The first instruction information is sent to the terminal device, where the terminal device maintains PUSCH transmission with the source network device before receiving the first instruction information, and the terminal device is receiving the first instruction information. After an indication message, PUSCH transmission with the target network device is started.
The method according to claim 8, further comprising:

Acquire second indication information, where the second indication information is used to indicate the minimum data convergence protocol of the uplink data packet that the terminal device needs to send to the target network device after converting to PUSCH transmission with the target network device PDCP serial number SN;

Sending the second indication information to the terminal device.
The method according to claim 9, wherein the second indication information includes a minimum PDCP SN of an uplink data packet sent by the terminal device to the target network device.
The method according to claim 9 or 10, wherein the second indication information includes a PDCP status report, and the PDCP status report is used to obtain the minimum number of uplink data packets that need to be sent to the target network device. PDCP SN.
The method according to any one of claims 9-11, wherein the PDCP SN is of bearer granularity.
The method according to any one of claims 8-12, further comprising:

Send uplink authorization information to the terminal device, where the uplink authorization information is allocated by the target network device to the terminal device and used for PUSCH transmission between the terminal device and the target network device.
The method according to any one of claims 8-13, wherein before the obtaining the first indication information, the method further comprises:

After receiving the RRC reconfiguration complete message from the terminal device, or after sending the RAR message to the terminal device, send third indication information to the source network device, where the third indication information is used to The source network device instructs the terminal device to successfully switch to the target network device.
The method according to claim 14, further comprising:

A PDCP status report is received from the source network device, where the PDCP status report is used to obtain the minimum PDCP SN of the uplink data packet of the uplink data that needs to be sent to the target network device.
The method according to any one of claims 8-13, wherein before the obtaining the first indication information, the method further comprises:

Receiving third indication information sent by the target network device, where the third indication information is used to indicate to the source network device that the terminal device successfully switches to the target network device.
The method according to claim 16, further comprising:

Receiving uplink authorization information sent by the target network device, where the uplink authorization information is allocated to the terminal device by the target network device and used for PUSCH transmission between the terminal device and the target network device.
A method of data transmission, characterized in that it comprises:

Receive fourth indication information, where the fourth indication information is used to indicate at least one PDCP sequence number SN corresponding to at least one packet data convergence protocol PDCP protocol data unit PDU one-to-one, and the at least one PDCP PDU is the source network device unsuccessful PDCP PDU sent to terminal equipment;

The at least one PDCP PDU is received from the target network device, and the at least one PDCP PDU is processed using parameters corresponding to the source network device, wherein the at least one PDCP PDU received from the target network device is from the source PDCP PDU of network equipment.
A method of data transmission, characterized in that it comprises:

Sending at least one PDCP PDU to the target network device, where the at least one PDCP PDU is a PDCP PDU that the source network device has not successfully sent to the terminal device;

Send fourth indication information to the terminal device or the target network device, where the fourth indication information is used to indicate at least one PDCP sequence number SN corresponding to the at least one PDCP PDU one-to-one.
A method of data transmission, characterized in that it comprises:

Receiving at least one PDCP PDU from a source network device, where the at least one PDCP PDU is a PDCP PDU that the source network device has not successfully sent to the terminal device;

Receiving fourth indication information from the source network device, where the fourth indication information is used to indicate the at least one PDCP sequence number SN corresponding to the at least one PDCP PDU;

Sending the fourth indication information and the at least one PDCP PDU to the terminal device.
A method of data transmission, characterized in that it comprises:

Acquire sixth indication information, which is used to indicate the mapping between the third PDCP SN corresponding to the third PDCP PDU received by the terminal device from the target network device and the PDCP SN allocated by the source network device for the third PDCP SDU Relationship, and the mapping relationship between the second PDCP SN corresponding to the second PDCP PDU received from the target network device and the PDCP SN allocated by the source network device for the second PDCP SDU, where the third PDCP The PDU is generated after the target network device uses the parameters corresponding to the target network device to process the third PDCP SDU from the source network device, and the third PDCP SN is allocated by the target network device The second PDCP PDU is generated after the target network device uses the parameters corresponding to the target network device to process the second PDCP SDU from the source network device, and the second PDCP SN is Allocated by the target network device, the third PDCP SDU is the first PDCP SDU sent by the source network device to the target network device before the target network device receives the second PDCP SDU The PDCP SDU that the target network device has not processed using the parameters corresponding to the target network device, and the second PDCP SDU is the PDCP SDU that the terminal device has not successfully received from the source network device;

The third PDCP PDU and the second PDCP PDU are received from the target network device, and the parameters corresponding to the target network device are used to process the third PDCP PDU and the second PDCP PDU according to the sixth indication information. PDCP PDU.
The method according to claim 21, wherein the processing the third PDCP PDU and the second PDCP PDU according to the sixth indication information using parameters corresponding to the target network device comprises:

Acquiring, according to the sixth indication information, the mapping relationship between the third PDCP SN corresponding to the third PDCP PDU received by the terminal device from the target network device and the PDCP SN allocated by the source network device for the third PDCP SDU, And, the mapping relationship between the second PDCP SN corresponding to the second PDCP PDU received from the target network device and the PDCP SN allocated by the source network device for the second PDCP SDU;

Process the second PDCP PDU according to the PDCP SN allocated by the source network device for the second PDCP SDU and the second PDCP SN, using the parameters corresponding to the target network device;

According to the PDCP SN allocated by the source network device to the third PDCP SDU and the third PDCP SN, use the parameters corresponding to the target network device to process the third PDCP PDU.
A method of data transmission, characterized in that it comprises:

Receiving a first PDCP SDU from a source network device, and a PDCP SN allocated by the source network device for the first PDCP SDU;

Receive a second PDCP SDU from the source network device, and the PDCP SN allocated by the source network device for the second PDCP SDU, the second PDCP SDU is a PDCP SDU that the terminal device did not successfully receive from the source network device ；

Send a third PDCP PDU and a second PDCP PDU to the terminal device, where the third PDCP PDU is generated by the target network device after processing the third PDCP SDU using the parameters corresponding to the target network device, and The second PDCP PDU is generated after the target network device uses the parameters corresponding to the target network device to process the second PDCP SDU, and the third PDCP SDU is generated when the target network device receives the second PDCP SDU. Before the PDCP SDU, the target network device in the first PDCP SDU has not yet processed the PDCP SDU using the parameters corresponding to the target network device;

Send sixth indication information, where the sixth indication information is used to indicate the mapping relationship between the third PDCP SN corresponding to the third PDCP PDU and the PDCP SN allocated by the source network device for the third PDCP SDU, and The mapping relationship between the second PDCP SN corresponding to the second PDCP PDU and the PDCP SN allocated by the source network device for the second PDCP SDU, where the second PDCP SN and the third PDCP SN are the Assigned by the target network device.
A method of data transmission, characterized in that it comprises:

Sending the first PDCP SDU to the target network device and the PDCP SN allocated by the source network device for the first PDCP SDU;

Send a second PDCP SDU to the target network device, and the PDCP SN allocated by the source network device for the second PDCP SDU, and the second PDCP SDU is a PDCP SDU that the terminal device did not successfully receive from the source network device ；

Receive sixth indication information from the target network device, where the sixth indication information is used to instruct the terminal device to receive the third PDCP SN corresponding to the third PDCP PDU received from the target network device and the source network device is the third The mapping relationship between the PDCP SN allocated by the PDCP SDU, and the second PDCP SN corresponding to the second PDCP PDU received from the target network device and the PDCP SN allocated by the source network device for the second PDCP SDU Mapping relationship, where the third PDCP PDU is generated after the target network device uses the parameters corresponding to the target network device to process the third PDCP SDU from the source network device, and the third PDCP SN Is allocated by the target network device, the second PDCP PDU is generated after the target network device uses the parameters corresponding to the target network device to process the second PDCP SDU from the source network device, and the The second PDCP SN is allocated by the target network device, and the third PDCP SDU is before the target network device receives the second PDCP SDU, and the target network device in the first PDCP SDU has not PDCP SDU processed using the parameters corresponding to the target network device;

Sending the sixth indication information to the terminal device.
The method according to any one of claims 21 to 24, wherein the sixth indication information comprises a first offset value and a second offset value, and the first offset value is relative to the third PDCP SN The source network device is the offset of the PDCP SN allocated by the third PDCP SDU, and the second offset value is the PDCP allocated by the second PDCP SN to the source network device for the second PDCP SDU SN offset; or

The sixth indication information includes at least one PDCP SN in the third PDCP SN and at least one of the PDCP SN allocated by the source network device corresponding to the at least one PDCP SN in the third PDCP SN PDCP SN, and at least one PDCP SN in the second PDCP SN and at least one PDCP SN in the PDCP SN allocated by the source network device corresponding to at least one PDCP SN in the second PDCP SN .
The method according to any one of claims 21-25, wherein the first offset value is determined according to the number of the second PDCP SDU, and the second offset value is determined according to the first An offset value and the number of fourth PDCP SDUs are determined, where the fourth PDCP SDU is before the target network device receives the second PDCP SDU, the target network in the first PDCP SDU The PDCP SDU processed by the device using the parameters corresponding to the target network device.
A communication device comprising a module for executing the method according to any one of claims 1 to 26.
A communication device, comprising a processor and a memory, the memory stores instructions, and when the processor executes the instructions, the device executes the method according to any one of claims 1 to 26 .
A computer-readable storage medium, characterized in that a computer program or instruction is stored in the storage medium, and when the computer program or instruction is executed by a communication device, the computer program or instruction is implemented as described in any one of claims 1 to 26 Methods.
A chip, characterized by comprising a processor and a communication interface, the processor is used to call and run instructions from the communication interface, and when the processor executes the instructions, it can implement any of claims 1 to 26 The method described in one item.