CN115694719A

CN115694719A - Data forwarding method and device for switching scenes

Info

Publication number: CN115694719A
Application number: CN202110857567.0A
Authority: CN
Inventors: 刘菁; 董朋朋; 曹振臻
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2021-07-28
Filing date: 2021-07-28
Publication date: 2023-02-03
Also published as: WO2023005885A1

Abstract

A data forwarding method and device for a switching scene are used for improving the transmission reliability of a UE switching process under the condition of executing network coding function transmission. According to the method, the source sending device can send a first data packet subjected to network coding processing to the receiving device, and forwards a second data packet to a target sending device of the receiving device according to the first information from the receiving device, wherein the second data packet is used for restoring original data of the first data packet by the receiving device. The first information may indicate the first SDU of the SDUs of the second protocol layer recovered by the receiving device according to the first data packet, the number information of the redundant packets to be received, and the number information of the first data packets received accurately or incorrectly. The method and the device provided by the application can be applied to the extended reality XR service or other services with requirements on time delay.

Description

Data forwarding method and device for switching scenes

Technical Field

The present application relates to the field of communications technologies, and in particular, to a method and an apparatus for forwarding data in a switched scenario.

Background

In a handover scenario, a receiving device may switch from one transmitting device (referred to as a source transmitting device) to another transmitting device (referred to as a target transmitting device). In the switching process, the source sending device may forward data that is not successfully received by the receiving device before switching to the target sending device, so that the target sending device sends the data to the receiving device after switching, and the receiving device is prevented from losing the data.

However, in the prior art, the switching of the receiving device does not consider the situation that the source sending device sends data processed by Network Coding (NC) to the receiving device, so a scheme considering the NC application of the sending device in the switching scenario is urgently needed.

Disclosure of Invention

The present invention provides a data forwarding method for switching scenarios, which is used to provide a scheme of applying an NC technique in a switching scenario, so as to improve the transmission reliability of a receiving device in a switching process when a sending device sends data to a receiving device by using a network coding technique.

In a first aspect, a data transmission method is provided. The method may be implemented by a source sending device, which may be the sending device or a component in the sending device. The source transmission device is for example a base station. The source transmitting device may be operable to transmit data processed by the network coding function to the receiving device.

Based on the method, a first data packet may be sent to a receiving device by a source sending device, where the first data packet includes an original data packet and/or a first redundant packet, or the first data packet includes a systematic packet and/or a first redundant packet. The first redundant packet may be processed by the original packet to perform a network coding function, the original packet being obtained from the original data, and the system packet being obtained from the original packet. The raw data in the method may be a Service Data Unit (SDU) of a first protocol layer to be processed for a network coding function. The source sending device may also receive the first information from the receiving device, and send a second data packet to a destination sending device of the receiving device according to the first information, where the second data packet is used for the receiving device to recover the original data. The first information may be used to indicate at least one of: the receiving device recovers a first SDU in SDUs of a second protocol layer according to the first data packet, where the second protocol layer and the first protocol layer are the same protocol layer or different protocol layers, and the SDU of the second protocol layer corresponds to the SDU of the first protocol layer, for example, the SDU of the second protocol layer is the SDU of the first protocol layer, or the SDU of the second protocol layer is obtained by processing the second protocol layer according to the SDU of the first protocol layer; or, the number information of the redundant packets to be received, where the redundant packets to be received are used by the receiving device to recover the original data; or, the receiving device receives the number information of the first data packets correctly or receives the number information of the first data packets incorrectly.

By adopting the method, the source sending equipment can acquire the receiving condition of the receiving equipment for the first data packet before switching according to the first information, and accordingly can send the second data packet to the target sending equipment according to the first information for the receiving equipment to recover the original data corresponding to the first data packet, so that the receiving equipment can still obtain the original data before switching after switching, packet loss is avoided, and transmission reliability can be improved.

In one possible design, the source sending device may not need to send the second data packet to the destination sending device if the first information indicates that the receiving device successfully decoded the first data packet. By adopting the design, the first information can be used for indicating that the receiving equipment does not have packet loss before switching, and the source sending equipment is not required to forward data to the target sending equipment, so that signaling and processing overhead among the sending equipment are saved.

In one possible design, the target sending device is a device that communicates with the receiving device after the receiving device performs the handover, and the source sending device is a device that communicates with the receiving device before the receiving device performs the handover. By adopting the design, the application scene of the method provided by the application is a switching scene, and the data transmission reliability of the receiving equipment under the scene that the receiving equipment is switched from the source sending equipment to the target sending equipment can be improved. Or, the target sending device is an auxiliary station for communicating with the receiving device, and the source sending device is a main station for communicating with the receiving device, so that the data transmission reliability under the double-connection scene can be improved.

In one possible design, the second data packet may include a second redundancy packet corresponding to the original data, and the second redundancy packet may include the first redundancy packet, and/or include redundancy packets other than the first redundancy packet. The type of the second data packet is now a redundant packet type. By adopting the design, the source sending equipment can send the second redundant packet corresponding to the original data to the target sending equipment, the target sending equipment sends the data packet to the receiving equipment according to the second redundant packet, and the receiving equipment can recover the SDU of the first protocol layer which is not successfully recovered before switching according to the received data packet. Because the second redundant packet is processed by network coding, the target sending equipment does not need to execute the network coding processing on the second redundant packet, and the processing overhead of the target sending equipment can be reduced.

In one possible design, the source transmitting device may further transmit first indication information to the destination transmitting device, where the first indication information is used to indicate that the type of the second data packet is a redundant packet type. By adopting the design, the target sending equipment can know the type of the second data packet, if the type of the second data packet is the type of the redundant packet, the second data packet is already a data packet subjected to network coding processing, and the target sending equipment does not need to perform network coding processing on the second data packet any more, so that the processing overhead is saved, and the receiving equipment can be ensured to recover the SDU of the first protocol layer according to the second data packet.

In one possible design, if the second packet is carried in a General Packet Radio Service (GPRS) tunneling protocol (GTP) tunnel, the first indication information is carried in a GTP header field of the GTP tunnel. By adopting the design, the first indication information can be carried by the GTP header field, and the efficient and flexible indication of the first indication information is realized. Or, the second data packet is carried in a general packet radio service tunneling protocol GTP tunnel; the method further comprises the following steps:

and the source sending equipment sends first indication information to the target sending equipment, wherein the first indication information is used for indicating the identification of the GTP tunnel bearing the second data packet of the redundant packet type.

Optionally, the first indication information may include an identifier of the GTP tunnel carrying the second data packet of the redundant packet type. Further, information indicating the type of the redundant packet may be included. The identity of the GTP tunnel is, for example, a Terminal End Identity (TEID) of the GTP tunnel. For example, the first indication information may be carried in an Xn application protocol (Xn Ap) message. Therefore, the target sending equipment can determine whether the corresponding second data packet needs to be subjected to network coding processing according to the first indication information, and efficient and flexible indication of the first indication information is achieved.

In one possible design, the second data packet may also include a second SDU of the SDUs of the second protocol layer that does not include the first SDU. The type of the second packet at this time is SDU type. By adopting the design, the source sending equipment can forward the SDU of the second protocol layer which is not successfully recovered by the receiving equipment before switching to the target sending equipment, and the target sending equipment can send the second SDU to the receiving equipment without carrying out network coding processing on the second SDU, so that the processing overhead is saved. In addition, the scheme can avoid the receiving equipment from obtaining the repeated SDUs of the second protocol layer before and after switching, and avoid the receiving equipment from repeatedly submitting data packets.

In one possible design, the source sending device may also send second indication information to the target sending device. Wherein the second indication information is used for indicating whether the target sending device executes the processing of the network coding function on the second data packet; and/or the second indication information is used for indicating that the type of the second data packet is the SDU type. By adopting the design, the target sending equipment can determine that the network coding processing is not required to be carried out on the second data packet according to the second indication information, the processing overhead of the target sending equipment can be reduced, and the receiving equipment can be ensured to successfully recover the second SDU. For example, a possible implementation manner of the design is that a source sending device adds 1bit (bit) information in a GTP header field of an Xn interface to indicate whether a second data packet forwarded through a GTP tunnel needs to be processed by a network coding function of a target sending device, for example, a value of the 1bit information is 0, which indicates that the target sending device needs to perform processing of the network coding function on the second data packet. In another possible implementation manner, the second indication information may indicate Sequence Number (SN) corresponding to an SDU that the target transmission device needs to perform network coding processing, and then the target transmission device may not perform processing of the network coding function on an SDU with SN smaller than the SN indicated by the second indication information, or the second indication information may indicate Sequence Number (SN) corresponding to an SDU that the target transmission device does not need to perform network coding processing, so that the target transmission device may not perform processing of the network coding function on an SDU with SN smaller than or equal to the SN indicated by the second indication information. Alternatively, the second indication information may indicate an identifier of a GTP tunnel carrying the second SDU. The method further comprises the following steps: and the source sending equipment sends second indication information to the target sending equipment, wherein the first indication information is used for indicating the identification of the GTP tunnel bearing the second data packet of the SDU type. Optionally, the second indication information may include an identifier of the GTP tunnel carrying the second SDU. Further, information indicating the type of SDU can also be included. The identity of the GTP tunnel is, for example, a Terminal End Identity (TEID) of the GTP tunnel. For example, the second indication information may be carried in an Xn application protocol (Xn Ap) message. Therefore, the target sending device can determine whether the corresponding second SDU needs to be subjected to network coding processing according to the second indication information, and efficient and flexible indication of the second indication information is realized.

In one possible design, if the second data packet includes a second redundant packet or a second SDU, the source transmitting device may further transmit third indication information to the target transmitting device, where the third indication information is used to indicate information of a first coding block that the target transmitting device performs network coding function processing, or the third indication information is used to indicate information of a last coding block that the source transmitting device performs network coding function processing. With this design, the target sending device may determine information of the coding block corresponding to the second data packet according to the third indication information, and avoid a collision between the information of the coding block of the second redundant packet or the second SDU and information of the coding block obtained by the target sending device performing subsequent network coding processing, so as to ensure that the receiving device successfully decodes the coding block from the target sending device.

In one possible design, the second data packet may include a set of SDUs of the second protocol layer corresponding to the original data. With this design, if the source transmission device can perform network coding processing on a set of SDUs of the second protocol layer corresponding to the original data during the process of obtaining the first data packet, the source transmission device can transmit the set of SDUs of the second protocol layer to the target transmission device, where the set of SDUs of the second protocol layer may include SDUs of the second protocol layer that are not recovered before the switching of the receiving device and SDUs of the second protocol layer that have been recovered, so that the receiving device can obtain a system packet and/or a redundant packet obtained by network coding the set of SDUs from the target transmission device to recover the original data, thereby improving transmission reliability.

In one possible design, the source transmitting device or the target transmitting device may further transmit fourth indication information to the receiving device, the fourth indication information being used to instruct the receiving device to delete data that is duplicated with all or part of the data in the SDU of the set of second protocol layers, wherein the duplicated data includes at least one of: the PDU of the second protocol layer, the coding packet corresponding to the PDU of the second protocol layer, or the SDU of the second protocol layer successfully recovered through the coding packet corresponding to the PDU of the second protocol layer. The coded packet may include a redundant packet, or a redundant packet and a system packet. By adopting the design, the receiving device deletes the duplicate packets according to the fourth indication information, so that the receiving device can be prevented from repeatedly submitting the same data packets, for example, submitting the same data packets to a layer above the second protocol layer. Wherein, the source transmitting device or the target transmitting device may transmit the fourth indication information to the receiving device through a Radio Resource Control (RRC) message.

In this design, the fourth indication information indicates the receiving device to delete the duplicated data, for example:

the fourth indication information includes an encoding block identification block ID (or a block ID list, i.e., a plurality of block IDs), and the receiving device may delete at least one of: and the PDCP SDU successfully recovered through the coding packets with the block ID smaller than or equal to the block ID carried by the fourth indication information or the PDCP PDU corresponding to the coding packets. The encoded packets may include systematic packets and/or redundant packets, among others. Or,

the fourth indication information includes a PDCP SN (or a PDCP SN list, i.e., a plurality of PDCP SNs), and the receiving device may delete at least one of the following according to the fourth indication information: the PDCP PDUs corresponding to the SNs, the PDCP PDUs, that is, the PDCP PDUs corresponding to the SNs, the corresponding encoded packets, or the PDCP SDUs successfully recovered through the encoded packets. Wherein each PDCP SN corresponds to one PDCP PDU. Or,

the fourth indication information includes start PDCP SN information and a bit map, the start PDCP SN corresponding to the start PDCP PDU. The bitmap can be used to indicate the PDCP PDUs following the starting PDCP PDU that need to be deleted, and the receiving device can delete at least one of the following according to the bitmap: PDCP PDUs after the starting PDCP PDU, coding packets corresponding to the PDCP PDUs, or PDCP SDUs successfully recovered through the coding packets. Or,

the fourth indication information may indicate a first PDCP PDU and/or a last PDCP PDU that the UE needs to delete, so that the receiving device may delete at least one of: the PDU positioned between the first PDCP PDU and the last PDCP PDU, the coding packets corresponding to the PDCP PDUs, or the PDCP SDUs successfully recovered through the coding packets.

In one possible design, the first protocol layer and the second protocol layer are the same protocol layer, and the SDU of the second protocol layer corresponding to the first packet has a first sequence number, where the first sequence number is used to identify the SDU of the second protocol layer. Each of the set of SDUs of the second protocol layer includes a first sequence number. Or, each SDU of the second protocol layers in the set of SDUs of the second protocol layers has a corresponding first sequence number, the set of SDUs of the second protocol layers is carried in a gprs tunneling protocol GTP tunnel, and the first sequence number is carried in a GTP header field of the GTP tunnel. The first sequence number is used to identify an SDU of the second protocol layer. By adopting the design, the SDUs of the second protocol layer obtained before and after the switching of the receiving equipment comprise the first sequence number, so that the receiving equipment can identify whether the SDUs of the second protocol layer obtained before and after the switching are repeated according to the first sequence number, and if the SDUs are repeated, the repeated SDUs can be deleted so as to avoid the receiving equipment from repeatedly submitting the same data packet.

In one possible design, the source sending device may further receive sixth indication information from the target sending device, where the sixth indication information is used to indicate whether the target sending device supports the processing of the network coding function. With this design, the source transmitting device can know whether the target transmitting device supports network coding.

In one possible design, the source sending device may also send configuration information of the network coding function to the target sending device, the configuration information including at least one of: network coding type, coding block size, system packet size, original data packet size, system packet number, redundant packet number, coding coefficient selection, or convolution depth. With this design, the source transmission device can configure the configuration information of the network coding to the target transmission device, so that the target base station uses the information to perform the processing of the network coding function. And when the target sending equipment adopts the configuration information of the same network coding function as the source sending equipment to perform network coding processing on the second data packet, the receiving equipment can adopt the decoding information of the same network coding function to perform decoding processing on the data packet which is subjected to the network coding processing before and after switching, so that the decoding efficiency is improved.

In one possible design, the first protocol layer includes a Service Data Adaptation Protocol (SDAP), radio Link Control (RLC), or Packet Data Convergence Protocol (PDCP) layer, and the second protocol layer includes a PDCP layer. With this design, if the first protocol layer includes an SDAP layer and the second protocol layer is a PDCP layer, the network coding function of the source transmitting device is performed at the SDAP layer. At this time, the SDU of the PDCP layer, i.e., the SDAP PDU, includes a data packet that is processed by network coding, and the source transmitting device can recover, by the target transmitting device, the second SDU from the SDU of the second protocol layer that has not been successfully recovered before the receiving device switches, and the target transmitting device can transmit the data packet to the receiving device according to the second SDU, and the second SDU can be recovered by the receiving device. In addition, the first protocol layer includes a PDCP layer or an RLC layer, and in the case of the second protocol layer, the network coding of the source sending device is performed on the PDCP layer, and the source sending device forwards to the target sending device the PDCP SDU that has not undergone network coding or the redundant packet obtained by the first protocol layer through network coding, where the PDCP SDU that has not undergone network coding corresponds to the SDU of the first protocol layer to be recovered, and the target sending device sends the PDCP SDU to the receiving device after performing network coding or without performing network coding processing, so that the receiving device recovers the SDU of the first protocol layer to be recovered. In this case, whether to network code the PDCP SDU can be based on protocol conventions or indications to the receiving device.

In a second aspect, a method for forwarding data in a switched scenario is provided. The method may be implemented by a receiving device. The receiving device is, for example, a terminal device or a chip usable for a terminal device.

Based on the method, the receiving device can receive the first data packet from the source transmitting device and transmit the first information to the source transmitting device. The receiving device may also receive a third data packet from the destination transmitting device, the third data packet corresponding to a second data packet transmitted by the source transmitting device to the destination transmitting device, the first information being usable for determination of the second data packet, and the second data packet being usable for recovery of the original data by the receiving device.

In one possible example, the target sending device is a device that communicates with the receiving device after the receiving device performs handover, and the source sending device is a device that communicates with the receiving device before the receiving device performs handover.

In one possible example, the second data packet may include at least one of: a second redundant packet corresponding to the original data, a second SDU in the SDUs of the second protocol layer, or a group of SDUs of the second protocol layer corresponding to the original data.

In one possible example, if the second data packet includes a second redundant packet corresponding to the original data, and the first protocol layer is higher than the second protocol layer, and the third data packet corresponds to a PDU of the second protocol layer, the PDU of the second protocol layer may carry a fifth indication information for indicating whether the PDU of the second protocol layer is processed by the network coding function. By adopting the design, when the network coding function is executed by the first protocol layer higher than the second protocol layer, the receiving device can know whether the PDU of the second protocol layer is subjected to network coding processing according to the fifth indication information, so as to determine whether to execute corresponding decoding processing on the PDU of the second protocol layer, and correctly receive the data in the third data packet. And executing corresponding decoding processing on the PDU of the second protocol layer, wherein the decoding processing comprises the steps of obtaining the SDU of the second protocol layer according to the PDU of the second protocol layer and decoding the SDU of the second protocol layer. Optionally, the fifth indication information may include 1-bit information, for example, when the value of the 1-bit information is 0, the PDU of the second protocol layer is indicated to be subjected to network coding processing, and when the value of the 1-bit information is 1, the PDU of the second protocol layer is indicated to be not subjected to network coding processing. For example, the fifth indication information may be carried in a header field of the PDU.

In one possible example, if the second data includes a second SDU of the second protocol layer and the third data packet corresponding to the second SDU includes a PDU of the second protocol layer, the receiving device may further receive fifth indication information from the source transmitting device, the fifth indication information being usable to indicate whether the PDU of the second protocol layer is subjected to the network coding process. With this design, if it is indicated that the PDU of the second protocol layer has not undergone network coding processing, the receiving device does not need to perform decoding corresponding to the network coding processing on the PDU of the second protocol layer in order to correctly receive the data in the third data packet. Optionally, the fifth indication information may be included in a PDU header field of the second protocol layer, and/or the fifth indication information may include 1-bit information.

In one possible example, the receiving device may receive fourth indication information from the source transmitting device or the target transmitting device, wherein the fourth indication information is usable to instruct the receiving device to delete data that is duplicated with all or part of the data in the set of SDUs of the second protocol layer, and the duplicated data includes at least one of: the PDU of the second protocol layer, the system and/or the redundant packet corresponding to the PDU of the second protocol layer, or the SDU of the second protocol layer successfully recovered through the system and/or the redundant packet corresponding to the PDU of the second protocol layer.

In this design, reference may be made to the corresponding description in the first aspect for a manner of instructing, through the fourth indication information, the receiving device to delete the repeated data, which is not described herein again.

In one possible example, if the second data includes a set of SDUs of the second protocol layer, and the second protocol layer and the first protocol layer are the same protocol layer, the SDUs of the second protocol layer corresponding to the first data packet and the third data packet each have a first sequence number, and the first sequence number is used to identify the SDUs of the second protocol layer. Each SDU in the set of SDUs of the second protocol layer includes a first sequence number, or each SDU of the second protocol layer in the set of SDUs of the second protocol layer has a corresponding first sequence number, the SDUs of the set of second protocol layers are carried in a gprs tunneling protocol GTP tunnel, and the first sequence number is carried in a GTP header field of the GTP tunnel.

In one possible design, the first protocol layer may include a SDAP layer, a RLC layer, or a PDCP layer, and the second protocol layer may include a PDCP layer.

Various terms in the methods and designs shown in the second aspect above may refer to the description of the corresponding terms in the first aspect.

The advantageous effects in the method and design shown in the second aspect above may be seen in the description of the response advantageous effects in the first aspect.

In a third aspect, a data transmission method is provided. The method may be implemented by a target sending device, which may be the sending device or a component in the sending device. The target transmitting device is for example a base station.

Based on the method, the target transmitting device receives a second data packet from the source transmitting device and transmits a third data packet to the receiving device, wherein the third data packet is obtained according to the second data packet. For example, the third packet is the second packet, or a packet obtained by processing according to the second packet. The second data packet is related to the first information, and the second data packet is used for recovering original data corresponding to the first data packet.

In one possible example, the second data packet includes a second redundant packet corresponding to the original data.

In one possible example, the target transmitting device may receive the first indication information from the source transmitting device.

In one possible example, the second data packet can include a second SDU of the SDUs of the second protocol layer.

In one possible example, the target sending device may also receive second indication information from the source sending device.

In one possible example, the target transmitting device may further receive third indication information from the source transmitting device.

In one possible example, the second data packet can include a set of SDUs of the second protocol layer corresponding to the original data.

In one possible example, the target transmitting device may further transmit fourth indication information to the receiving device. Optionally, the fourth indication information may be received from the source sending device for the target sending device.

In one possible example, if the second data includes a set of SDUs of the second protocol layer, the protocol data units PDU of the second protocol layer corresponding to the first data packet and the third data packet each include a first sequence number, and the first sequence number is used for identifying the SDUs of the second protocol layer; the SDU of each second protocol layer in the SDU of the second protocol layer comprises a first sequence number, the first sequence number is used for identifying the SDU of the second protocol layer, or the SDU of each second protocol layer in the SDU of the second protocol layer has a corresponding first sequence number, the first sequence number is used for identifying the SDU of the second protocol layer, and the SDU of the second protocol layer is loaded in a GTP tunnel, and the first sequence number can be carried in a GTP head field of the GTP tunnel.

In one possible example, the target transmission device may further receive sixth indication information from the source transmission device, the sixth indication information indicating whether the target transmission device supports the processing of the network coding function.

In one possible example, the target transmitting device may also receive configuration information from the network coding function of the source transmitting device.

Various terms in the methods and designs shown in the above third aspect, such as the first indication information, the second indication information, the third indication information, the fourth indication information, the configuration information of the network coding function, and the like, may refer to the descriptions of the corresponding terms in the first aspect or the second aspect.

The advantageous effects in the method and design shown in the above third aspect can be seen in the description of the respective advantageous effects in the first or second aspect.

In a fourth aspect, an embodiment of the present application provides a communication apparatus, which may implement the method implemented by the source sending device in the foregoing first aspect or any possible design thereof. The apparatus comprises corresponding units or means for performing the above-described method. The means comprising may be implemented by software and/or hardware means. The device may be, for example, a source sending device, or a chip, a chip system, a vehicle-mounted communication module, a processor, or the like, which can support the source sending device to implement the method described above.

Illustratively, the communication device may include a transceiver unit (or called communication module, transceiver module) and a processing unit (or called processing module), which may perform the corresponding functions of the source sending device in the first aspect or any possible design thereof. When the communication apparatus is a source transmission device, the transceiving unit may be a transmission unit when performing the transmitting step, the transceiving unit may be a reception unit when performing the receiving step, and the transceiving unit may be replaced by a transceiver, the transmission unit may be replaced by a transmitter, and the reception unit may be replaced by a receiver. The transceiver unit may include an antenna, a radio frequency circuit, and the like, and the processing unit may be a processor, such as a baseband chip and the like. When the communication apparatus is a component having the function of the source transmission device, the transceiver unit may be a radio frequency unit, and the processing unit may be a processor. When the communication device is a chip system, the transceiving unit may be an input/output interface of the chip system, and the processing unit may be a processor of the chip system, for example: a Central Processing Unit (CPU).

The transceiving unit may be adapted to perform the actions of receiving and/or transmitting performed by the source transmitting device in the first aspect or any possible design thereof. For example, it may be used to perform the transmission of the first data packet, the second data packet, the first to fourth indication information and the configuration information of the network coding function performed by the source transmission apparatus shown in the first aspect, and the reception of the first information and the sixth indication information shown in the first aspect.

The processing unit may be adapted to perform actions other than the receiving and transmitting performed by the source transmitting device in the first aspect or any possible design thereof. For example, the processing unit may be configured to generate a data packet and information transmitted by the source transmission apparatus in the method of the first aspect, or to process information received by the source transmission apparatus in the method of the first aspect.

Optionally, the communication device may include a transceiver module and/or a communication module.

Optionally, the communication device may include a processor and/or a transceiver. The communication device may also include a memory.

Alternatively, the communication means may be implemented by a circuit.

In a fifth aspect, an embodiment of the present application provides a communication apparatus, which may implement the method implemented by the receiving device in the second aspect or any possible design thereof. The device comprises corresponding units or means for performing the above-described method. The means comprised by the apparatus may be implemented by software and/or hardware. The apparatus may be, for example, a receiving device, or a chip, a chip system, a processor, or the like that can support the receiving device to implement the method described above.

For example, the communication device may include a transceiver unit (or communication module, transceiver module) and a processing unit (or processing module), which may perform the corresponding functions of the receiving device in the second aspect or any possible design thereof. When the communication apparatus is a receiving device, the transceiving unit may be a transmitting unit when performing the transmitting step, the transceiving unit may be a receiving unit when performing the receiving step, and the transceiving unit may be replaced by a transceiver, the transmitting unit may be replaced by a transmitter, and the receiving unit may be replaced by a receiver. The transceiving unit may comprise an antenna, a radio frequency circuit and the like, and the processing unit may be a processor, such as a baseband chip and the like. When the communication device is a component having the above-mentioned receiving apparatus function, the transceiver unit may be a radio frequency unit, and the processing unit may be a processor. When the communication device is a chip system, the transceiving unit may be an input/output interface of the chip system, and the processing unit may be a processor of the chip system, for example: a CPU.

The transceiving unit may be adapted to perform the actions of receiving and/or transmitting performed by the receiving device in the second aspect or any possible design thereof. For example, it may be used to perform the address for the reception of the first packet, the third packet, the fourth indication information, the fifth indication information, or to perform the transmission of the first information, performed by the receiving apparatus shown in the second aspect.

The processing unit may be adapted to perform actions other than the receiving and sending performed by the receiving device in the second aspect or any possible design thereof. For example, the processing unit may be adapted to generate information to be transmitted by the receiving device in the method of the second aspect, or to process data packets and information received by the receiving device in the method of the second aspect.

Optionally, the communication device may comprise a transceiver module and/or a communication module.

Alternatively, the communication means may be implemented by a circuit.

In a sixth aspect, an embodiment of the present application provides a communication apparatus, which may implement the method implemented by the target sending device in the third aspect or any possible design thereof. The apparatus comprises corresponding units or means for performing the above-described method. The means comprised by the apparatus may be implemented by software and/or hardware. The apparatus may be, for example, a target sending device, or a chip, a chip system, a processor, or the like that can support the target sending device to implement the foregoing method.

Illustratively, the communication device may include a transceiver unit (or communication module, transceiver module) and a processing unit (or processing module), which may perform the corresponding functions of the target sending device in the third aspect or any possible design thereof. When the communication apparatus is the target transmission device, the transceiving unit may be the transmission unit when the transmission step is performed, the transceiving unit may be the reception unit when the reception step is performed, and the transceiving unit may be replaced by a transceiver, the transmission unit may be replaced by a transmitter, and the reception unit may be replaced by a receiver. The transceiver unit may include an antenna, a radio frequency circuit, and the like, and the processing unit may be a processor, such as a baseband chip and the like. When the communication apparatus is a component having the above-described function of the target transmission device, the transceiver unit may be a radio frequency unit, and the processing unit may be a processor. When the communication device is a chip system, the transceiving unit may be an input/output interface of the chip system, and the processing unit may be a processor of the chip system, for example: a CPU.

The transceiving unit may be adapted to perform the actions of receiving and/or transmitting performed by the target transmitting device in the third aspect or any possible design thereof. For example, it is possible to perform the reception of the second packet, the first to fourth indication information, and the configuration information of the network coding function performed by the target transmission apparatus shown in the third aspect, and the transmission of the third packet and the sixth indication information shown in the third aspect. The processing unit may be adapted to perform actions other than the receiving and transmitting performed by the target transmitting device in the third aspect or any possible design thereof. For example, the processing unit may be adapted to generate data packets and information to be transmitted by the receiving device in the method of the third aspect, or to process data packets and information received by the receiving device in the method of the third aspect.

Alternatively, the communication means may be implemented by a circuit.

In a seventh aspect, a communication system is provided, which includes the communication apparatus shown in the fourth to sixth aspects.

In an eighth aspect, there is provided a computer readable storage medium for storing a computer instruction or a program which, when run on a computer, causes the computer to perform the method described in the first to third aspects or any one of its possible implementations.

A ninth aspect provides a computer program product which, when run on a computer, causes the computer to perform the method of the first to third aspects or any one of its possible designs.

In a tenth aspect, there is provided a circuit, coupled to a memory, for performing the method of the first to third aspects or any one of its possible implementations. The circuit may comprise a chip circuit, a chip or a system of chips, etc.

The advantageous effects of the above second to tenth aspects and their possible designs may be referred to those of the first aspect and its possible designs.

Drawings

Fig. 1 is a schematic architecture diagram of a communication system according to an embodiment of the present application;

fig. 2 (a) is a schematic architecture diagram of another communication system provided in the embodiment of the present application;

fig. 2 (b) is a schematic structural diagram of another communication system according to an embodiment of the present application;

fig. 2 (c) is a schematic structural diagram of another communication system according to an embodiment of the present application;

fig. 2 (d) is a schematic structural diagram of another communication system according to an embodiment of the present application;

fig. 3 is a schematic architecture diagram of another communication system according to an embodiment of the present application;

fig. 4 (a) is a schematic architecture diagram of another communication system provided in the embodiment of the present application;

fig. 4 (b) is a schematic diagram of an architecture of a protocol stack according to an embodiment of the present application;

fig. 4 (c) is an architecture diagram of another protocol stack provided in the embodiment of the present application;

fig. 5 is a schematic diagram of a handover process according to an embodiment of the present application;

fig. 6 is a schematic diagram of another handover process provided in the embodiment of the present application;

fig. 7 (a) is a schematic diagram of a network coding process provided in an embodiment of the present application;

fig. 7 (b) is a schematic diagram of another network coding process provided in the embodiment of the present application;

fig. 8 is a schematic diagram of another network encoding process provided in the embodiment of the present application;

fig. 9 is a schematic flowchart of a data forwarding method for scene switching according to an embodiment of the present application;

fig. 10 is a schematic diagram of another handover process provided in the embodiment of the present application;

fig. 11 is a schematic diagram of another handover process provided in the embodiment of the present application;

fig. 12 is a schematic diagram of another handover process provided in the embodiment of the present application;

fig. 13 is a schematic diagram of another handover process provided in the embodiment of the present application;

fig. 14 is a schematic diagram of another handover process provided in the embodiment of the present application;

fig. 15 is a schematic diagram of another handover process provided in the embodiment of the present application;

fig. 16 is a schematic structural diagram of a communication device according to an embodiment of the present application;

fig. 17 is a schematic structural diagram of another communication device according to an embodiment of the present application.

Detailed Description

The technical solutions in the embodiments of the present application will be described below with reference to the drawings in the embodiments of the present application.

In the embodiments of the present application, terms such as "first" and "second" are used to distinguish the same or similar items having substantially the same function and action. For example, the first information and the second information are only used for distinguishing different information, and the order of the first information and the second information is not limited. Those skilled in the art will appreciate that the terms "first," "second," etc. do not denote any order or quantity, nor do the terms "first," "second," etc. denote any order or importance.

In the embodiments of the present application, "at least one" means one or more, "a plurality" means two or more. "and/or" describes the association relationship of the associated objects, meaning that there may be three relationships, e.g., a and/or B, which may mean: a exists alone, A and B exist simultaneously, and B exists alone, wherein A and B can be singular or plural. The character "/" generally indicates that the former and latter associated objects are in an "or" relationship. "at least one of the following" or similar expressions refer to any combination of these items, including any combination of the singular or plural items. For example, at least one (one) of a, b, or c, may represent: a, b, c; a and b; a and c; b and c; or a and b and c. Wherein a, b and c can be single or multiple.

To facilitate understanding of the data transmission method provided in the embodiments of the present application, a system architecture and an application scenario of the data transmission method provided in the embodiments of the present application will be described below. It can be understood that the system architecture and the application scenario described in the embodiment of the present application are for more clearly illustrating the technical solution of the embodiment of the present application, and do not constitute a limitation on the technical solution provided in the embodiment of the present application.

Fig. 1 is a schematic architecture diagram of a communication system 1000 to which an embodiment of the present application is applied. As shown in fig. 1, the communication system includes a radio access network 100 and a core network 200, and optionally, the communication system 1000 may further include an internet 300. The radio access network 100 may include at least one radio access network device (e.g., 110a and 110b in fig. 1) and may further include at least one terminal (e.g., 120a-120j in fig. 1). The terminal is connected with the wireless access network equipment in a wireless mode, and the wireless access network equipment is connected with the core network in a wireless or wired mode. The core network device and the radio access network device may be separate physical devices, or the function of the core network device and the logical function of the radio access network device may be integrated on the same physical device, or a physical device may be integrated with a part of the function of the core network device and a part of the function of the radio access network device. The terminals and the radio access network devices can be connected with each other in a wired or wireless mode. Fig. 1 is a schematic diagram, and other network devices, such as a wireless relay device and a wireless backhaul device, may also be included in the communication system, which are not shown in fig. 1.

The radio access network device may be a device having a radio transceiving function. The radio access network device may be a device providing wireless communication function services, typically located on the network side, including but not limited to: a next generation base station (gnnodeb, gNB) in a fifth generation (5 th generation,5 g) communication system, a next generation base station in a sixth generation (6 th generation,6 g) mobile communication system, a base station in a future mobile communication system or an access Node in a WiFi system, a wireless access point, an evolved Node B (eNB) in an LTE system, a Radio Network Controller (RNC), a Node B (Node B, NB), a base station controller (base station controller, BSC), a home base station (e.g., home evolved Node B, or home Node B, RNC), a base band unit (base band unit, BBU), a transmission reception point (transmission reception point, TRP), a transmission point (transmission point, TP), a base transceiver station (base transceiver station, BTS), and the like.

In a network configuration, the access network device may comprise a Centralized Unit (CU) node, or a Distributed Unit (DU) node, or a RAN device comprising a CU node and a DU node, or a control plane CU node and a user plane CU node, and a RAN device of a DU node. The access network device provides service for a cell, and a user equipment communicates with a base station through transmission resources (for example, frequency domain resources or spectrum resources) used by the cell, where the cell may be a cell corresponding to the base station (for example, a base station), and the cell may belong to a macro base station or a base station corresponding to a small cell (small cell), where the small cell may include: urban cell (metro cell), micro cell (microcell), pico cell (pico cell), femto cell (femto cell), etc., and these small cells have the characteristics of small coverage and low transmission power, and are suitable for providing high-rate data transmission service. The radio access network device may be a macro base station (e.g., 110a in fig. 1), a micro base station or an indoor station (e.g., 110b in fig. 1), a relay node or a donor node, a device in a V2X communication system that provides a wireless communication service for a user equipment, a radio controller in a Cloud Radio Access Network (CRAN) scenario, a relay station, a vehicle-mounted device, a wearable device, a network device in a future evolution network, and the like. The embodiments of the present application do not limit the specific technology and the specific device form used by the radio access network device. For convenience of description, the following description will be made with a base station as an example of the radio access network apparatus.

A terminal may also be referred to as a terminal device, a User Equipment (UE), a Mobile Station (MS), a Mobile Terminal (MT), etc., and may be an entity, such as a mobile phone, on the user side for receiving or transmitting signals. The terminal device may be a User Equipment (UE), wherein the UE includes a handheld device, a vehicle-mounted device, a wearable device, or a computing device having wireless communication functionality. Illustratively, the UE may be a mobile phone (mobile phone), a tablet computer, or a computer with wireless transceiving function. The terminal device may also be a Virtual Reality (VR) terminal device, an Augmented Reality (AR) terminal device, a wireless terminal in industrial control, a wireless terminal in unmanned driving, a wireless terminal in telemedicine, a wireless terminal in smart grid, a wireless terminal in smart city (smart city), a wireless terminal in smart home (smart home), and so on. The terminal can be widely applied to various scenes, for example, device-to-device (D2D), vehicle-to-equipment (V2X) communication, machine-type communication (MTC), internet of things (IOT), virtual reality, augmented reality, industrial control, automatic driving, telemedicine, smart grid, smart furniture, smart office, smart wearing, smart transportation, smart city, and the like. The terminal can be cell-phone, panel computer, take the computer of wireless transceiver function, wearable equipment, vehicle, unmanned aerial vehicle, helicopter, aircraft, steamer, robot, arm, intelligent home equipment etc.. In the embodiment of the present application, the apparatus for implementing the function of the terminal may be a terminal; or may be a device capable of supporting the terminal to implement the function, such as a chip system, or a communication module, or a modem, etc., which may be installed in the terminal. In the embodiment of the present application, the chip system may be composed of a chip, and may also include a chip and other discrete devices. In the technical solution provided in the embodiment of the present application, a device for implementing a function of a terminal is a terminal, and the terminal is a UE as an example, the technical solution provided in the embodiment of the present application is described. The embodiment of the present application does not limit the specific technology and the specific device form adopted by the terminal device.

Optionally, the UE may also be configured to act as a base station. For example, the UE may act as a scheduling entity that provides sidelink signals between UEs in vehicle-to-outside-association (V2X), device-to-device (D2D), peer-to-peer (P2P), or the like.

The base stations and terminals may be fixed or mobile. The base station and the terminal can be deployed on land, including indoors or outdoors, handheld or vehicle-mounted; can also be deployed on the water surface; it may also be deployed on airborne airplanes, balloons, and satellite vehicles. The embodiment of the application does not limit the application scenarios of the base station and the terminal.

The roles of base station and terminal may be opposite, e.g., helicopter or drone 120i in fig. 1 may be configured as a mobile base station, 120i being the base station for those terminals 120j that access radio access network 100 through 120 i; however, for the base station 110a, 120i is a terminal, i.e. the base station 110a and 120i communicate with each other via a radio interface protocol. Of course, 110a and 120i may communicate with each other through an interface protocol between the base station and the base station, and in this case, 120i is also the base station as compared to 110 a. Therefore, the base station and the terminal may be collectively referred to as a communication apparatus, and 110a, 110b, and 120a to 120j in fig. 1 may be referred to as communication apparatuses having their respective corresponding functions, for example, a communication apparatus having a base station function or a communication apparatus having a terminal function.

The base station and the terminal, the base station and the base station, and the terminal can communicate through the authorized spectrum, the unlicensed spectrum, or both the authorized spectrum and the unlicensed spectrum; communication may be performed in a frequency spectrum of 6 gigahertz (GHz) or less, in a frequency spectrum of 6GHz or more, or in a frequency spectrum of 6GHz or less and in a frequency spectrum of 6GHz or more. The embodiments of the present application do not limit the spectrum resources used for wireless communication.

In the embodiments of the present application, the functions of the base station may also be performed by a module (e.g., a chip) in the base station, or may also be performed by a control subsystem including the functions of the base station. The control subsystem including the base station function may be a control center in an application scenario of the terminal, such as a smart grid, industrial control, intelligent transportation, and smart city. The functions of the terminal may also be performed by a module (e.g., a chip or a modem) in the terminal, or by a device including the functions of the terminal.

Further, the present application may be applied to various specific communication scenarios, for example, scenarios such as point-to-point transmission between a base station and a terminal or between terminals (e.g., fig. 2 (a) is point-to-point transmission between a base station and a terminal), multi-hop transmission between a base station and a terminal (e.g., fig. 2 (b) and fig. 2 (c)), dual Connectivity (DC) or multi-connection between multiple base stations and terminals (e.g., fig. 2 (d)). It should be noted that, the specific communication application scenarios described above are only examples and are not limiting. In particular, from the perspective of services, the embodiments of the present application are applicable to a variety of service scenarios, such as a data coding scenario in an extended reality (XR) service, an upstream high-capacity scenario, and the like. In addition, fig. 2 (a) to 2 (d) do not limit the network architecture applicable to the present application, and the present application does not limit the uplink, downlink, access link, backhaul (backhaul) link, sidelink (sidelink) and other transmissions.

Referring to fig. 3, fig. 3 is a simplified schematic diagram of a communication system provided in an embodiment of the present application. For simplicity, fig. 3 only shows base station 110, UE 120, and network 130. The base station 110 comprises an interface 111 and a processor 112. The processor 112 may optionally store a program 114. The base station 110 may optionally include a memory 113. Memory 113 may optionally store a program 115.UE 120 includes an interface 121 and a processor 122. The processor 122 may optionally store a program 124.UE 120 may optionally include memory 123. Memory 123 may optionally store a program 125. These components work together to provide the various functions described in this application. For example, processor 112 and interface 121 work together to provide a wireless connection between base station 110 and UE 120. Processor 122 and interface 121 cooperate to implement downlink transmissions and/or uplink transmissions for UE 120.

The network 130 may include one or

more network nodes

130a, 130b to provide core network functionality. The

network nodes

130a, 130b may be 5G core network nodes, or earlier generation (e.g. 4G, 3G or 2G) core network nodes. For example, the

networks

130a, 130b may be Access Management Functions (AMFs), mobility Management Entities (MMEs), and the like. Network 130 may also include one or more network nodes in a Public Switched Telephone Network (PSTN), a packet data network, an optical network, an Internet Protocol (IP) network. Wide Area Networks (WANs), local Area Networks (LANs), wireless Local Area Networks (WLANs), wired networks, wireless networks, metropolitan area networks, and other networks to enable communication between UEs 120 and/or base stations 110.

A processor (e.g., processor 112 and/or processor 122) may include one or more processors and be implemented as a combination of computing devices. The processors (e.g., processor 112 and/or processor 122) may each include one or more of the following: a microprocessor, microcontroller, digital Signal Processor (DSP), digital Signal Processing Device (DSPD), application Specific Integrated Circuit (ASIC), field Programmable Gate Array (FPGA), programmable Logic Device (PLD), gating logic, transistor logic, discrete hardware circuitry, processing circuitry, or other suitable hardware, firmware, and/or combination of hardware and software for performing the various functions described herein. The processor (e.g., processor 112 and/or processor 122) may be a general-purpose processor or a special-purpose processor. For example, processor 112 and/or processor 122 may be a baseband processor or a central processor. The baseband processor may be used to process communication protocols and communication data. The central processor may be used to cause the base station 110 and/or the UE 120 to execute software programs and process data in the software programs.

Interfaces (e.g., interfaces 111 and/or 121) may include components for enabling communication with one or more computer devices (e.g., UEs, BSs, and/or network nodes). In some embodiments, the interface may include wires for coupling a wired connection, or pins for coupling a wireless transceiver, or chips and/or pins for a wireless connection. In some embodiments, the interface may include a transmitter, a receiver, a transceiver, and/or an antenna. The interface may be configured to use any available protocol (e.g., 3GPP standard).

The programs in this application are used to represent software in a broad sense. Non-limiting examples of software are program code, programs, subroutines, instructions, instruction sets, code segments, software modules, applications, software applications, and the like. The programs may be executable in the processor and/or the computer to cause the base station 110 and/or the UE 120 to perform various functions and/or processes described herein.

The memory (e.g., storage 113 and/or storage 123) may store data that is manipulated by the

processors

112, 122 when executing software. The

memories

113, 123 may be implemented using any memory technology. For example, the memory may be any available storage medium that can be accessed by the processor and/or computer. Non-limiting examples of storage media include: RAM, ROM, EEPROM, CD-ROM, removable media, optical disk storage, magnetic disk storage media, magnetic storage devices, flash memory, registers, state memory, remote mounting storage, local or remote memory components, or any other medium that can carry or store software, data, or information and that can be accessed by a processor/computer.

The memory (e.g., storage 113 and/or storage 123) and the processor (e.g., processor 112 and/or processor 122) may be provided separately or integrated together. The memory may be used in connection with the processor such that the processor can read information from, store information in, and/or write information to the memory. The memory 113 may be integrated in the processor 112. The memory 123 may be integrated in the processor 122. The processor (e.g., processor 113 and/or processor 123) and the memory (e.g., processor 112 and/or processor 122) may be disposed in an integrated circuit (e.g., the integrated circuit may be disposed in a UE or a base station or other network node).

As shown in fig. 4 (a), taking gNB as an example, when the base station adopts a CU-DU separation architecture, one possible application scenario of the method in the present application includes: the gNB consists of 1 gNB-CU and 1 or more gNB-DUs, wherein one gNB-DU can be connected to only one gNB-CU, the gNB-CU and the gNB-DU are connected through an F1 interface, and the gNB-CU and a 5G core network (5G core, 5GC) are connected through an NG interface. The gNB and the gNB (or gNB-CU) can be connected through an Xn (or Xn-C) interface.

The UE may access the gNB-CU through the gNB-DU, and optionally, a physical layer (PHY), a Medium Access Control (MAC) and a Radio Link Control (RLC) layer function that is peer to the UE is located on the gNB-DU, and a PDCP, service Data Adaptation Protocol (SDAP) and RRC layer function that is peer to the UE is located on the gNB-CU, as shown in fig. 4 (b) and (c).

For the control plane, as shown in fig. 4 (b), in the Uplink (UL) direction, the gNB-DU encapsulates the RRC message generated by the UE in an F1 application protocol (F1 AP) message of the F1 interface and sends the encapsulated RRC message to the gNB-CU. In a Downlink (DL) direction, a gNB-CU encapsulates an RRC message in an F1AP message and sends the message to a gNB-DU, and the gNB-DU extracts the RRC message from the F1AP message, maps the RRC message to an SRB (SRB 0/SRB1/SRB 2) corresponding to a radio (Uu) interface and sends the RRC message to UE. As shown in fig. 4 (b), the control plane may also relate to the processing of the gNB-DU and the gNB-CU at the protocol layers such as Stream Control Transmission Protocol (SCTP), IP, layer 2 (L2) or layer 1 (L1), etc., and to the processing of the UE and the gNB-DU at the protocol layers such as RLC, MAC, and PHY, etc., and to the processing of the UE and the gNB-CU at the protocol layers such as RRC and PDCP, etc.

For the user plane, as shown in fig. 4 (c), in the UL direction, the gNB-DU maps the UE packet received from the Uu interface DRB to the user plane (GTP-U) of the corresponding General Packet Radio Service (GPRS) tunneling protocol (GTP) tunnel, and sends the UE packet to the gNB-CU. In the DL direction, the gNB-CU maps the UE data packet into the corresponding GTP tunnel and sends the GTP tunnel to the gNB-DU, the gNB-DU extracts the UE data packet from the GTP tunnel, and maps the UE data packet onto the DRB corresponding to the Uu interface and sends the DRB to the UE. As shown in fig. 4 (b), the user plane may also relate to processing of the gNB-DU and the gNB-CU at a protocol layer such as User Datagram Protocol (UDP), IP, L2, or L1, and to processing of the UE and the gNB-DU at a protocol layer such as RLC, MAC, and PHY, and to processing of the UE and the gNB-CU at a protocol layer such as SDAP and PDCP.

In existing mechanisms, the UE may perform a handover. The handover here is, for example, a handover of the UE from a source base station, e.g., source gNB (S-gNB), to a target base station, e.g., target gNB (T-gNB). Wherein, the processing in the switching process is different for the services using different RLC transmission modes. The RLC transmission mode includes an Unacknowledged Mode (UM) and an Acknowledged Mode (AM). In the AM mode, in order to ensure reliability of service transmission, automatic repeat-request (ARQ) processing needs to be performed, that is, the UE needs to feed back an RLC status report in the RLC layer, so that the source base station triggers ARQ retransmission. In the UM mode, the reliability of service transmission is not required to be guaranteed, and ARQ processing is not required to be performed, i.e., the receiving end does not need to feed back the RLC status report. When the base station adopts a CU-DU separation architecture, after receiving an RLC status report fed back by the UE, the gbb-DU can know the receiving condition of the UE for a PDCP Protocol Data Unit (PDU), and send a downlink data transmission status (DDDS) message to the gbb-CU, where the DDDS message can carry the receiving condition information of the PDCP PDU by the UE, so as to further notify the receiving condition of the PDCP PDU by the UE to the gbb-CU.

It should be understood that, in the present application, in the case of a CU-DU split architecture, the CU of the source base station may be denoted as S-gNB-CU, and the DU of the source base station may be denoted as S-gNB-DU. Similarly, the CU of the target base station can be denoted as T-gNB-CU and the DU of the target base station can be denoted as T-gNB-DU.

Here, the following data processing is taken as an example, and the processing method of each of the source base station, the target base station, and the UE when handover occurs will be described.

UM mode

(1) The source base station forwards PDCP SDUs to the target base station, excluding SDUs that have been processed by the PDCP layer of the source base station and sent to the RLC layer. That is, as long as the source base station transfers PDCP PDUs corresponding to PDCP SDUs to the RLC layer, the source base station does not forward the PDCP SDUs to the target base station on the Xn interface regardless of whether the UE receives the PDCP SDUs.

(2) And the target base station sets the TX _ NEXT to be 0, namely, the forwarded PDCP SDU received through the Xn interface is numbered and processed from the PDCP SN =0, and the PDCP PDU is generated and sent to the UE.

(3) The UE sets RX _ NEXT to 0, i.e., resumes receiving PDCP PDUs from SN =0.

As shown in fig. 5, the PDCP layer of the S-gNB (source gNB) receives PDCP SDU1, PDCP SDU2, PDCP SDU3 and PDCP SDU4 from the upper layer, where PDCP SDU1 and PDCP SDU2 have been processed by the PDCP layer to generate PDCP PDU1 and PDCP PDU2 and delivered to the RLC layer, and then during the UE handover process, the S-gNB-CU only forwards PDCP SDU3 and PDCP SDU4 to the T-gNB-CU through the Xn-C interface, and does not forward PDCP SDU1 and PDCP SDU2 to the T-gNB-CU any more. In this application, the PDCP layer process refers to at least one of an association PDCP SN, header compression, ciphering/integrity protection process, or adding a PDCP header. And on the side of the T-gNB (target gNB), starting from SN =0, processing the PDCP SDU from the S-gNB, performing PDCP layer processing on the PDCP SDU to generate PDCP PDU and transmitting the generated PDCP PDU to the UE. For example: the T-gNB generates PDCP PDU3 using SN =0 for PDCP SDU3 and transmits it to the UE, and the T-gNB generates PDCP PDU4 using SN =1 for SDU4 and transmits it to the UE. The UE receives the corresponding PDCP PDU from the T-gbb starting from SN =0.

(II) AM mode

(1) The source base station forwards PDCP SDUs to the target base station, which excludes SDUs that the UE has successfully received. That is, the RLC layer of the source base station can determine the reception condition of RLC SDUs (equivalent to PDCP PDUs) at the UE side according to ARQ feedback of the UE. The source base station forwards the PDCP SDU corresponding to the RLC SDU which does not receive the RLC ACK feedback to the target base station on an Xn interface, because the PDCP SDU is processed in the source base station and is associated with a PDCP SN, in order to ensure the continuity of the service, when the source base station forwards the PDCP SDU to the target base station, the source base station also needs to forward the SN associated with the SDU, so that the target base station generates the PDCP PDU to send to the UE after continuously processing the PDCP SDU by using the original associated SN. For example, the source base station forwards the PDCP SDU to the target base station through a GTP tunnel and carries the associated SN of the PDCP SDU in a GTP tunnel header field. In addition, the source base station also forwards PDCP SDUs which are not processed by the PDCP layer to the target base station on an Xn interface, and the target base station processes the PDCP SDUs by using DL COUNT values carried in the SN state transfer message to generate PDCP PDUs and sends the PDCP PDUs to the UE. And (3) the UE processes the received PDCP PDUs in sequence according to the sizes of the SNs.

As shown in fig. 6, the source base station receives PDCP SDU1, PDCP SDU2, PDCP SDU3, and PDCP SDU4, wherein PDCP SDU1 and PDCP SDU2 are processed by the PDCP layer to generate PDCP PDU1 (corresponding to PDCP SN = 0) and PDCP PDU2 (corresponding to PDCP SN = 1), and then the generated PDCP PDU1 and PDCP SDU2 are sent to the UE. According to the feedback of the RLC status report of the UE, the source base station can know that the UE has not correctly received the SDU2, therefore, in the switching process of the UE, the source base station forwards the PDCP SDU2, the PDCP SDU3 and the PDCP SDU4 to the target base station on an Xn interface, and carries the information of PDCP SN =1 when forwarding the SDU2, and in addition, the source base station also sends an SN status transfer message to the target base station, and the DL COUNT value carried in the message contains the information of PDCP SN = 2. The target base station processes the received SDU2 by using SN =1 to generate a PDCP PDU2 and then sends the PDCP PDU2 to the UE, processes the received PDCP SDU3 by using SN =2 to generate a PDU3 and then sends the PDU3 to the UE, and processes the received PDCP SDU4 by using SN =3 to generate a PDU4 and then sends the PDU4 to the UE.

The foregoing briefly explains the system architecture and possible application scenarios of the embodiments of the present application, and in order to better understand the technical solutions of the embodiments of the present application, the following briefly introduces network coding.

The network coding function in the present application includes network coding of an original data packet and adding a coding packet header. The network coding can be realized by an encoder, the input of the encoder is K original data packets, the output of the encoder is N coded data packets (coded packets for short), wherein N and K are positive integers, and N is greater than K. The coded packets include N-K (N minus K) redundant packets and K systematic packets, or N redundant packets (i.e., the coded packets are all redundant packets and do not include systematic packets). The content of the body of the system packet is consistent with the content of the original data packet (that is, the system packet is composed of a header of the encoding packet and the original data packet), that is, the encoding coefficient of the system packet is a unit vector. Alternatively, the system packet may be obtained by directly adding a header to the original data packet. The coding coefficients of the redundant packet are non-unit vectors. Through the correlation between the content of the redundant packet and the content of the original data packet generating the redundant packet, the receiving device can recover the original data packet which is not successfully received through decoding the redundant packet and the original data packet or the system packet which is successfully received together. Based on the characteristics of network coding, the packet sizes of the original data packets are equal. Further, the network coding function may further include processing the original data to obtain equal-sized original data packets, where the processing may include one or more of splitting, concatenating, or padding (padding). The network coding function of the transmitting device corresponds to the network decoding function of the receiving device. The receiving device may recover the K original data packets by decoding at least K encoded packets that were successfully received together. The protocol layer having the network coding function or the decoding function corresponding to the network coding is referred to as a network coding/decoding layer, and in the present application, the network coding/decoding layer is referred to as a network coding layer for short, that is, the protocol layer having the network coding is referred to as a network coding layer. In this application, the original data may be SDU of a certain protocol layer.

The network coding layer may be a Radio Resource Control (RRC) layer, an SDAP layer, a PDCP layer, a Backhaul Adaptation Protocol (BAP) layer, a Radio Link Control (RLC) layer, a Medium Access Control (MAC) layer, or a PHY layer. The network coding layer may also be a new protocol layer other than the PHY layer, the MAC layer, the RLC layer, the BAP layer, the PDCP layer, the SDAP layer, and the RRC layer, and may be a network coding layer added above the PDCP layer (e.g., in 5G NR, a network coding layer is added between the PDCP layer and the SDAP layer), or a network coding layer added above the BAP layer, or a network coding layer is added between the PDCP layer and the RLC layer, or a network coding layer is added between the RLC layer and the MAC layer, or a network coding layer is added between the MAC layer and the PHY layer.

Commonly used network coding schemes include two broad classes of block codes and convolutional codes, wherein the scheme of the block code includes one or more of Random Linear Network Coding (RLNC), deterministic Linear Network Coding (DLNC), batch sparse code (bat code), erasure code (erasure code), fountain code (fountain code), maximum distance separable code (MDS code), lubar transform code (LT) code, fast cyclone (rapid cyclone) code, raptor q code, rateless (rate) code, and Reed-Solomon (Reed-Solomon, RS) code, etc., and the scheme of the convolutional code includes one or more of Convolutional Network Coding (CNC) code, stream coding (CNC) and sliding window coding (window).

Two possible network coding flows for the network coding function of the sending device (called originating for short) are described below.

A first possible network coding procedure:

the method includes acquiring original data, where the original data may be SDUs of a protocol layer that performs network coding, that is, PDUs received by the protocol layer that performs network coding. Describing the original data as a PDU, the sending device may obtain the original data packet with the same size by performing one or more of segmentation, concatenation, padding, and the like on one or more PDUs. The original data packet carries a corresponding relation between each original data packet and one or more PDUs corresponding to the original data packet. The carrying may be explicit carrying, for example, carrying a position mapping relationship between each original data packet and one or more PDUs corresponding to the original data packet, or implicit carrying, for example, the corresponding relationship between each original data packet and one or more PDUs corresponding to the original data packet is default. So that the receiving device (called simply the receiving end) can recover the PDU from the original packet based on the correspondence.

Optionally, the header of each original data packet carries a correspondence between the original data packet and one or more PDUs corresponding to the original data packet. In this case, one possible implementation is: the PDU is firstly subjected to one or more of the processing of the segmentation, the cascade connection, the padding and the like to obtain original data, and then a packet header is added to the original data to obtain an original data packet with the same size.

Optionally, the correspondence may be indicated by a segmentation and/or concatenation condition of the one or more PDUs.

It is to be understood that if the original data itself is equal-sized, the step of obtaining the original data packet with equal-sized by one or more of dividing, concatenating or padding one or more PDUs or SDUs can be skipped, i.e. the PDUs or SDUs are the original data packets with equal-sized.

Fig. 7 (a) and fig. 7 (b) take PDU sizes as original Data and the corresponding relationship mentioned above is carried by a Header (denoted as Header) as an example, PDU1 to PDU4 are processed to obtain original Data1 to PDU4, where the processing of PDU may be one or more of division, concatenation or padding. The size of the original data may or may not be equal. Then, the group of original data is subjected to a packet header adding operation to obtain K original data packets, i.e., pkt1 to Pkt4 in fig. 7 (a) and fig. 7 (b), where the original data packets can be understood as data packets that are not encoded, and the original data packets have the same size.

And then a plurality of original data packets with the same size are coded.

Specifically, encoding a plurality of original packets of equal size may be performed in any one of three ways.

Mode 1 as shown in fig. 7 (a), N-K encoded packets, which may be referred to as redundant packets or check packets, i.e., EPkt1 to EPkt2 shown in fig. 7 (a), can be obtained by encoding a set of K original data packets and adding an encoded packet Header (denoted as NC _ Header). Wherein K is a positive integer, and N is a positive integer not less than K.

Through the operation, the transmitting end finally transmits K original data packets and N-K redundant packets.

Modes

2 and 3 are shown in fig. 7 (b), N encoded packets, such as EPkt1 to EPkt6 in the figure, are obtained by processing K original data packets, and the encoded packets may be divided into systematic packets and redundant packets, and the systematic packets may also be referred to as systematic data packets. Wherein the encoded packet header may include a coefficient factor field indicating that the encoded coefficient of the encoded packet is obtained. The system (EPkt 1-EPkt 4) is composed of a coding packet header and a packet body, the content of the packet body is consistent with that of an original data packet, and a coefficient factor field included in the packet header is a unit vector. Therefore, the process of processing the original data packet to obtain the systematic packet may include two

modes

2 and 3, where K is a positive integer and N is a positive integer not less than K.

In the method 2, the system packet is generated by directly adding the encoding packet header to the original data packet, i.e. without encoding.

In the method 3, the original data packet is encoded, that is, after being encoded by the coefficient factor which is a unit vector, and the system packet is generated by adding the packet header of the encoded packet.

The redundant packets in the

modes

2 and 3 are generated in the same manner, and are generated by encoding an original data packet and adding an encoded packet header. As shown in fig. 7 (b), N-K redundant packets (e.g., EPkt5 to EPkt 6) are generated from K original data packets (e.g., pkt1 to Pkt 4) by encoding and adding encoded packet headers, and the packet parts (EData 1 to EData 1) thereof are the result of the addition of the K original data packets multiplied by coefficient factors, wherein the coefficient factors are non-unit vectors.

Through the above operation, the transmitting end finally transmits N encoded packets.

Correspondingly, still taking fig. 7 (a) as an example, for the receiving end, for the mode 1, the receiving end receives at least K data packets, and the K data packets are linearly independent, that is, the rank of the corresponding coefficient matrix is equal to K, so that the receiving end can recover K original data packets through decoding, and then recover corresponding PDUs. The at least K data packets may be all redundant packets, or some original data packets and some redundant packets, which is not limited herein. It is understood that if the receiving end receives K original data packets, the decoding may not be performed.

For the mode 2 and the mode 3, still taking fig. 7 (b) as an example, the receiving end receives at least K data packets, and the K data packets are linearly independent, that is, the rank of the corresponding coefficient matrix is equal to K, so that the receiving end can recover K original data packets through decoding, and then recover corresponding PDUs. The at least K data packets may be all redundant packets, or may be partially systematic packets and partially redundant packets, which is not limited herein. It can be understood that if the receiving end receives K systematic packets, decoding may not be performed, and the header processing of the de-encoded packets may be performed.

In the above network coding function, original data packets with equal size are obtained by performing one or more of segmentation, concatenation, or padding on one or more original data, where the original data packets carry a correspondence between each original data packet and one or more original data corresponding to the original data packet.

A second possible network coding procedure:

in a second possible network coding process, the original data packet with equal size may be obtained by one or more of virtual partitioning, concatenation or padding. In this way, the original data and the header information of each original data are mapped into a cache, which may be a real cache or a virtual cache, and the header information of each original data indicates the location of each original data mapped in the cache. And then obtaining a plurality of original data packets with the same size from the cache. And then coding a plurality of original data packets with the same size to obtain a coded packet. The manner of obtaining a plurality of original data packets with equal size from the buffer may be preset, or indicated to the receiving end by the transmitting end, or indicated to the other party after determined by the controlling party of the two parties of data transmission. In this way, the original data packet has no header, but the equal-sized data segment obtained from the buffer in the present solution is still referred to as the original data packet in consideration of the alignment with the description in the first way. It is understood that the original data packet in the present scheme may also be referred to as an original data segment.

The method for encoding a plurality of original data packets with equal size to obtain encoded packets is similar to the method 1 in the first possible implementation procedure, and is different from the method 1 in that after encoding, a transmitting end sends one or more original data and header information of the one or more original data, and one or more redundant packets obtained by encoding.

It will be appreciated that the input to the network coding layer may be one or more original data units, such as original data, and the output of the network coding layer may be one or more PDUs, which may include the aforementioned original data packets and redundant packets, or the aforementioned systematic packets and redundant packets. Outputting the one or more PDUs may be understood as outputting the one or more PDUs to a module subsequently processing the one or more PDUs in the terminal device or in the network device via the communication interface. It is to be understood that the output referred to in this application may refer to sending signals over an air interface, or may refer to outputting signals to other modules in an apparatus (e.g., a terminal device or a network device) through a communication interface. The specific process is specifically described in the application scenario, and is not described herein again.

The specific coding operation is briefly described by taking RLNC as an exampleAnd (5) clearing. The RLNC scheme uses a coding block (block) as a coding unit, wherein one coding block comprises a plurality of original data packets with the same size, and a group of coding packets can be obtained by constructing a coding coefficient matrix to code the original data packets. Typically, the coefficients in the matrix of coding coefficients are chosen randomly in a finite field, such as a Galois Field (GF). Referring to fig. 8, fig. 8 is a schematic diagram of random linear network coding. As shown in FIG. 8, the coefficient matrix (i.e., A in FIG. 8) is encoded ^(W+R)×W ) The size is (W + R) × W, i.e., (W + R) rows and W columns, wherein, in this example, one row vector in the coding coefficient matrix is referred to as a coding coefficient vector, and the coding block (X in fig. 8) containing W original data packets is processed by decoding ^W×1 ) Performing network coding to obtain W + R coded data (Y in FIG. 8) ^(W+R)×1 ) The corresponding code rate is represented as W/(W + R), or the corresponding redundancy rate is represented as R/(W + R). Wherein, the coding coefficient matrix randomly selects coefficients in GF (q) domain, q represents the size of Galois field, the value of Galois field is interval [0, q-1 ]]. W and R are both positive integers. It should be understood that in the RLNC scheme, there is no association between each coding block, where W + R coded data obtained by performing network coding on a coding block including W original data packets, that is, the coding operation is performed on each independent coding block, and the redundancy (code rate) of each coding block may be the same or different. The encoding end/transmitting equipment uniformly adds packet header information to W original data packets and the generated W + R encoded data and then transmits the W original data packets, and when the decoding end/receiving equipment receives at least W correct encoded packets which are not linearly related to the encoding coefficient vector, or when the decoding end/receiving equipment receives at least W correct encoded packets and the rank of the encoding coefficient matrix corresponding to the received encoded packets is W, the W original data packets can be correctly decoded and recovered. This is because the encoded packet fuses information of several original data packets, so that the receiving device can recover the original data packets by using the encoded packet.

Some terms referred to in the present application are described below.

The system comprises the following steps: the encoding data generated by multiplying the original data packet by the encoding coefficient of the unit vector is added with the encoding packet header, or the original data packet is directly added with the encoding packet header to obtain the encoding data. E.g. original numbersThe data packet is network coded by a coding coefficient matrix (namely, A (W + R) xW in figure 8) with the size of (W + R) xW to obtain W + R coded data, wherein the coding coefficient matrix can be written into

Sub-matrix I formed by W rows _W Is a unit matrix composed of W unit vectors, and W + R encoded data obtained corresponding to I _W The partial W coded data are the data parts of the W system packets, and the system packets are obtained by adding packet header information to the coded data.

Redundant packets: the method is generated by network coding the original data packet, and the coding coefficient of the redundant packet is a non-unit vector. For example, the network coding is performed by using a coding coefficient matrix (i.e., a (W + R) × W in fig. 8) with a size of (W + R) × W to obtain W + R coded data, wherein the coding coefficient matrix can be written as

Corresponding to G in W + R encoded data _R×W The partial R coded data is the data part of R redundant coded packets, and the R coded data is added with packet header information to obtain redundant packets. In the embodiments of the present application, the term "redundant packet" may also be referred to as "check packet", and both may be used interchangeably.

Network coding grouping: the term "block code" refers to a set of network coded packets that contain a plurality of original data packets. For example, dividing each W original data packets into a network coding packet for independent network coding may obtain the coded data corresponding to the network coding packet. In embodiments of the present application, the term "network coded packet" may also be referred to as a "network coded block", "coded packet", or "coded block".

Network coding window: the network coding window is a term used for a network coding scheme or a convolutional code comprising a sliding window, the network coding window is a set comprising a plurality of original data packets, and the original data packets contained in different network coding windows can be partially identical. For example, W original data packets are obtained by sliding a window for L original data packets, L and W are positive integers, L is not less than W, the positive integers are used as a current network coding window, the W original data packets in the network coding window are network coded to obtain coded data corresponding to the network coding window, the network coding window is slid to obtain another group of original data packets as data packets to be coded, it should be noted that the size of the network coding window may be different before and after the sliding, the size of the network coding window refers to the number of the original data packets contained in the network coding window, and the original data packets contained in the network coding window before and after the sliding may be partially the same. In the embodiments of the present application, the term "network coding window" may also be referred to as "network coding window", "network coding sliding window", "coding window", "sliding window", or "sliding window", etc.

Network coding depth: the network coding window is a term used for a network coding scheme or a convolutional code including a sliding window, and the network coding depth is the number of original data packets coded within the network coding window or the size of the network coding window. For example, W original data packets are obtained by sliding a window for L original data packets, where L and W are both positive integers and L is not less than W, and are used as a current network coding window, and network coding is performed on W original data packets in the network coding window to obtain coded data corresponding to the network coding window, where the current network coding depth is W. In the embodiments of the present application, the term "network coded depth" may also be referred to as "network coded convolutional depth", "coded depth", "convolutional depth", "sliding window size", or "window size", etc.

Network coding convolution depth: the same as 'network coding depth'.

Network coding sliding window: the same as the network coding window.

A finite field: also called galois field, is a field that contains only a limited number of elements and can perform addition, subtraction, multiplication and division operations without the result of the addition, subtraction, multiplication and division operations exceeding the set of fields.

The decoding condition is corresponding to the network coding, and the decoding condition indicates the success rate and/or failure rate of decoding corresponding to the network coding packet or the network coding sliding window within a period of time, wherein all original data packets in the network coding packet or the network coding sliding window are successfully decoded, which is called as the success rate of decoding the network coding packet or the network coding sliding window, otherwise, the success rate is called as the failure rate of decoding the network coding packet or the network coding sliding window, i.e. the ratio of the network coding packet successfully decoded within a period of time to all the network coding packets, or the ratio of the network coding sliding window successfully decoded within a period of time to all the network coding sliding windows, and the failure rate is the ratio of the network coding packet failed in decoding within a period of time to all the network coding packets, or the ratio of the network coding sliding window failed in decoding within a period of time to all the network coding sliding windows.

Network coding rate: the network coding rate refers to a ratio of the number of original data packets to the number of coded packets, or the network coding rate refers to a ratio of the number of original data packets newly participating in coding in a current coding window to the number of total data packets corresponding to the current coding window, or a ratio of the number of original data packets contained in the current network coding window to the number of coded packets corresponding to the current network coding window. The number of the original data packets newly participating in encoding is the number of the original data packets contained after the sliding window slides minus the number of the original data packets contained before the sliding window slides, and the number of the encoding packets is the sum of the number of the system packets and the number of the redundant packets, or the number of the redundant packets.

Network coding layer: the network coding layer refers to a protocol layer with a network coding function, and the network coding layer may be one or more of RRC layer, SDAP layer, PDCP layer, BAP layer, RLC layer, MAC layer, or PHY layer and other protocol layers with the network coding function. The specific layer is not limited in this application. The network coding layer may also be a new protocol layer other than the above protocol layers, for example, the new protocol layer may be above the PDCP layer, above the BAP layer, between the PDCP layer and the RLC layer, between the RLC layer and the MAC layer, or between the MAC layer and the PHY layer, and the location of the new protocol layer may not be limited in this application. In the embodiments of the present application, the term "network coding layer" may also be referred to as "coding/decoding layer", "network coding/decoding layer", or other names, which are not limited in this application.

Decoding corresponding to network coding: the decoding of the network coding is the inverse process of the network coding, and the original data packet can be recovered by multiplying the inverse matrix of the matrix corresponding to the coding data by utilizing the received coding data.

Rank (rank) of the encoded data versus matrix: the number of packets for which the coding coefficient vectors are linearly independent can be reflected.

Protocol Data Unit (PDU): the PDU, which contains information from the upper layer and additional information from the entity of the current layer, is transferred to the next lower layer.

Service data unit (PDCP SDU): the data unit transferred between protocol layers is data from or to be transferred to an upper layer.

The method provided by the embodiment of the present application is described below with reference to a flowchart.

It should be understood that the method provided by the embodiment of the present application may be executed by a sending device and a receiving device. The sending device may be the foregoing base station, or may be a host node, for example: an Integrated Access Backhaul (IAB) host (IAB node, integrated access and backhaul). The receiving device may be a UE or a relay node, such as an IAB node. The following describes actions performed by the receiving device by taking the UE as an example, and actions performed by the transmitting device by taking the base station as an example, actions performed by other receiving nodes may refer to actions of the UE, and actions performed by other transmitting nodes may refer to actions of the base station.

It should be understood that in a handover scenario, a UE may be handed over from one transmitting device (referred to as a source transmitting device) to another transmitting device (referred to as a target transmitting device), for example, the source transmitting device may be a source base station and the target transmitting device may be a target base station. The method provided by the embodiment of the present application is described below by taking UE, source network device, and target network device as execution subjects. The source network device may be a source base station or a gNB-CU (hereinafter referred to as a source gNB-CU) of the source base station in a CU-DU separation scenario, and/or the target network device may be a target base station or a gNB-CU (hereinafter referred to as a target gNB-CU) of a target base station in the CU-DU separation scenario.

In the following description of the present application, a data transmission or reception method provided in the embodiments of the present application is described by taking an example in which a source transmission device is a source base station, a target transmission device is a target base station, a reception device is a UE, and a network code is a block code. It is to be understood that the embodiments of the present application are also applicable to network coding as convolutional codes. The embodiments of the present application may be applied to a handover scenario or a dual connectivity scenario, which is described below with the handover scenario as an example. In the switching scene, the target sending equipment is equipment which communicates with the UE after the UE performs switching, and the source sending equipment is equipment which communicates with the UE before the UE performs switching.

As shown in fig. 9, the data transmitting or receiving method provided in the embodiment of the present application may include the following steps:

s101: the source base station transmits a first data packet to the UE.

It should be understood that the present application does not limit the protocol layer (which may be referred to as the first protocol layer later) of the process by which the source base station performs the network coding function. The first protocol layer may be one of a SDAP layer, a PDCP layer, or an RLC layer. For example, taking the first protocol layer as an SDAP layer as an example, the PDCP SDU received by the PDCP layer of the source base station is a data packet that is processed by the SDAP to perform a network coding function, and at this time, the PDCP layer of the source base station may perform PDCP layer processing on the PDCP SDU to obtain a PDCP PDU. For another example, taking the PDCP layer performing the network coding function as an example, the PDCP layer of the source base station may perform the network coding function on the PDCP SDU, perform PDCP layer processing, obtain a PDCP PDU, and send the PDCP PDU to the UE. The process of performing network coding on the PDCP SDU can refer to the description of fig. 7 (a) and/or fig. 7 (b), but should not be construed as being limited to the process of performing the network coding function by using the method shown in fig. 7 (a) and fig. 7 (b).

In this application, the first data packet may include an original data packet and/or a first redundant packet, or the first data packet may include a systematic packet and/or a first redundant packet, where the first redundant packet is obtained by performing a network coding operation according to the original data packet, the systematic packet is obtained according to the original data packet, and the original data packet is obtained according to the original data. In this application, the original data is SDU to be processed by the network coding function of the first protocol layer. For example, when the source base station performs the processing of the network coding function by using the method shown in fig. 7 (a), the first data packet from the source base station to the UE may include a redundant packet EPkt1 and a redundant packet EPkt2. For another example, when the source base station performs the processing of the network coding function by using the method shown in fig. 7 (b), the first data packet may include system packets EPkt1 to EPkt4 and redundant packets EPkt5 to EPkt6.

Accordingly, the UE receives the first data packet and then performs a corresponding decoding process of the network coding function, which may specifically refer to the description of the decoding process of the UE shown in fig. 7 (a) and/or fig. 7 (b).

S102: the UE sends first information to the source base station, and the first information can be used for indicating the receiving condition of the UE for the first data packet.

Specifically, the first information may indicate a first SDU of SDUs of a second protocol layer, e.g., a PDCP layer, recovered by the UE according to the first data packet. Wherein the SDUs of the second protocol layer correspond to the original data (i.e. the SDUs of the first protocol layer), or the SDUs of the second protocol layer are all SDUs of the second protocol layer obtained from the original data. The first SDU is the SDU of the second protocol layer recovered by the UE according to the first data packet, and comprises part or all of the SDUs of the second protocol layer.

Alternatively, the first information may indicate information on the number of redundant packets to be received, and the redundant packets to be received may be used for the UE to recover the original data. The first information may then be used to request a redundant packet to be received. For example, if there are n unrecovered first SDUs in the UE, the UE may indicate that the number of redundant packets to be received by the UE is n through the first information to request no less than n redundant packets.

Or the number information of the first data packets correctly received by the UE. The source base station may determine, according to the number information, the number of first data packets that the UE has not correctly received, and then the source base station may send second redundant packets that are not less than the number to the target base station.

Alternatively, the first information may indicate information on the number of first data packets that the UE did not correctly receive (or erroneously receive), and the source base station may transmit not less than the number of second redundant packets to the target base station.

In addition, the method provided by the embodiment of the present application may also be used in a transmission scenario of the UM mode or the AM mode of the RLC layer. In the AM mode, the first information may be an RLC status report or a feedback information other than the RLC status report, and is used to trigger the source base station to send the second data to the target base station. In UM mode, the first information may also be a PDCP status report sent to the source base station before the UE switches to the target base station. The source base station may send indication information to the UE for indicating the UE to send the PDCP status report to the source base station before the UE is handed over to the target base station. Alternatively, the first information may be other feedback information sent by the UE to the source base station before the handover to the target base station.

Accordingly, the source base station receives the first information.

S103: and the source base station sends a second data packet to the target base station according to the first information, wherein the second data packet is used for the UE to recover the original data of the first data packet.

In this application, the type of the second data packet may include a redundant packet type, or the second data packet includes a second redundant packet, and the second redundant packet corresponds to the original data. Here, corresponding to the original data, it means that the second data packet is a redundant packet obtained by a network coding operation from the original data. The second redundant packet may be the same as the first redundant packet, or may be a redundant packet obtained by the source base station through network coding operation again after receiving the first information, where the coding coefficient matrix for obtaining the second redundant packet may be the same as or different from the coding coefficient matrix for obtaining the first data packet, and the application is not particularly limited.

The second data packet may also include a second SDU of the SDUs of the second protocol layer that corresponds to the SDU of the first protocol layer, and the second SDU does not include the first SDU. The first SDU is an SDU of the second protocol layer recovered by the UE according to the first data packet, that is, the second SDU is an SDU of the second protocol layer that is not recovered by the UE according to the first data packet. Taking the second protocol layer as a PDCP layer, the second SDU may be a second PDCP SDU that the UE has not recovered from the PDCP SDUs.

The second data packet may also include a set of SDUs of the second protocol layer corresponding to the original data packet. The SDUs of the second protocol layer correspond to the same coding block (the convolutional codes correspond to the same coding window), that is, the SDUs of the first protocol layer corresponding to the SDUs of the second protocol layer are used as a group of SDUs to perform network coding operation. The SDUs of the second protocol layer include SDUs of the second protocol layer which are not recovered by the UE according to the first data packet. Taking the example that the second protocol layer is a PDCP layer, the set of SDUs of the second protocol layer may be a set of PDCP SDUs corresponding to the same coding block.

Accordingly, the target base station receives the second data packet.

S104: and the target base station sends a third data packet to the UE, and the third data packet is obtained according to the second data packet. For example, the third packet is obtained by performing PDCP layer processing and/or network coding processing on the second packet according to the manner of obtaining the third packet from the second packet. For example, the second packet may be a PDCP SDU, and the third packet may be a PDCP PDU.

Optionally, if the second data packet includes the second redundant packet or includes the second SDU in the SDUs of the second protocol layer, the target base station does not need to perform a network coding operation on the second redundant packet, for example, the target base station may send the second data to the third data packet as the third data packet. The target base station may perform a network coding operation on the second redundant packet if the second data packet includes a set of SDUs of the second protocol layer corresponding to the original data.

Accordingly, the UE may receive the third data packet and recover the original data from the third data packet.

By using the method shown in fig. 9, the source base station can know the receiving condition of the first data packet before the handover of the UE according to the first information, and the source base station can also send the second data packet to the target base station according to the first information, so that the UE can recover the original data corresponding to the first data packet according to the data packet received from the target base station, so that the UE can still obtain the original data before the handover after the handover, and packet loss is avoided, thereby improving transmission reliability.

In addition, the first information may also indicate that the UE successfully decoded the first data packet, and then the source base station does not need to send the second data packet to the target base station at this time. The source base station can transmit data to the target base station according to the first information or the packet loss does not occur before the UE is switched, so that signaling and processing overhead between the base stations are saved.

In the method provided by the embodiment of the present application, the source base station sends the second data packet to the target base station. It should be understood that, in the following example, the first data packet includes a system packet and a first redundant packet as an example, and in practical applications, the first data packet may also include an original data packet and a first redundant packet, and the application is not particularly limited. In addition, the following example is described by taking a deployment manner of base stations with separated CUs-DUs as an example, according to actual needs, a source base station in the following description may be replaced by a source gNB-CU, a target base station may be replaced by a target gNB-CU, and in actual applications, a base station with separated CU-DU deployment may also be replaced by a base station with combined CU and DU deployment.

Example 1

In example 1, the source base station and the target base station both support the network coding function, and the network coding function is located in the PDCP layer. In addition, example 1 is described by taking as an example a scheme (i.e., the scheme illustrated in fig. 7 (b)) in which the source base station transmits the encoded packet including the systematic packet and the redundant packet to the UE before handover, and the target base station transmits the encoded packet including the systematic packet and the redundant packet to the UE after handover.

Example 1 may include the following steps 1 to 3:

step 1, the source base station sends PDCP PDU to the UE, wherein the PDCP PDU comprises a system packet or a redundant packet.

The source base station performs network coding function processing on a plurality of received PDCP SDUs (which can be called original data) to generate coded packets (including systematic packets and redundant packets), and then adds PDCP headers to the generated coded packets to generate PDCP PDUs. As shown in fig. 10, the source base station performs network coding function processing on the received PDCP SDU1, PDCP SDU2, and PDCP SDU3 to generate 4 coded packets (including 2 systematic packets and 2 redundant packets), and then adds a PDCP header to the 4 coded packets to generate a PDCP PDU0 (including systematic packet 1), a PDCP PDU1 (including systematic packet 2), a PDCP PDU2 (including redundant packet 1), and a PDCP PDU3 (including redundant packet 2), that is, PDCP PDU0 to PDCP PDU3 serve as first data packets. That is, the coded packets and PDCP PDUs have a one-to-one correspondence, i.e.: one coded packet corresponds to one PDCP PDU.

And 2, the source base station receives the first information sent by the UE.

The source base station receives first information sent by the UE. Accordingly, the UE transmits the first information to the source base station.

The first information is used for indicating the condition that the UE receives the coded packet, and comprises at least one of the following information:

the method comprises the steps of successfully decoding indication information of PDCP PDU 0-PDCP PDU3, successfully received PDCP SDU information, to-be-received redundant packet number information, correctly received first data packet (or PDCP PDU) number information or incorrectly received first data packet (or PDCP PDU) number information.

And 3, the source base station forwards data to the target base station according to the first information.

In the present application, unless specifically stated otherwise, the forwarding refers to that the source base station forwards data to the target base station according to the first information.

The source base station forwards data to the target base station over the Xn interface (the forwarded data may be referred to as forwarded data, including but not limited to the second data packet, and may also include PDCP SDUs that the source base station has not undergone PDCP layer processing, and/or PDCP SDUs that have performed processing for network coding functions at the source base station but have not yet been sent to the UE). In example 1, the type of the forwarding data includes at least a redundant packet type, or the type of the second data packet in example 1 is a redundant packet type. In addition, the type of forwarding data in example 1 may further include an SDU type.

The following description is made separately depending on the type of forwarding data.

a. The source base station forwards the second redundant packet to the target base station on the Xn interface. The second redundant packet is the second data packet.

As a possible implementation manner, the source base station forwards the second redundant packet to the target base station according to the first information sent by the UE. The forwarded second redundant packet may include a redundant packet that the source base station has not yet sent to the UE. And the number of the forwarded second redundant packets is greater than or equal to the number of redundant packets which need to be received when the UE successfully decodes the original data.

For example, if the first information is information indicating the number of the second redundant packets requested by the UE, the number of the redundant packets that the UE still needs to receive to successfully decode and recover the original data may be indicated by the first information. Or, if the first information is the number information of the first data packets correctly received by the UE, the source base station may determine, according to the first information, the number of second redundant packets that the UE needs to receive after successfully decoding and recovering the original data. Or, the first information is the number information of the encoded packets that the UE did not correctly receive, and the source base station may determine, according to the first information and the number information of the first data packets that the source base station has sent to the UE, the number of the second redundant packets that the UE needs to receive after successfully decoding and recovering the original data.

As shown in fig. 10, the source base station performs network coding function processing on the received PDCP SDU1, PDCP SDU2, and PDCP SDU3 to generate 4 coded packets (including 2 systematic packets and 2 redundant packets), and then adds a PDCP header to the 4 coded packets to generate a PDCP PDU0 (including systematic packet 1), a PDCP PDU1 (including systematic packet 2), a PDCP PDU2 (including redundant packet 1), and a PDCP PDU3 (including redundant packet 2), where the PDCP PDU0 to PDCP PDU3 are first data packets or coded packets. It should be understood that, in the present application, the PDCP PDU refers to a PDCP PDU with SN = n, where n is a non-negative integer. For example, PDCP PDU0 in fig. 10 refers to PDCP PDU with SN =0 in fig. 10, PDCP PDU1 refers to PDCP PDU with SN =1 in fig. 10, PDCP PDU2 refers to PDCP PDU with SN =2 in fig. 10, and so on.

Assuming that the UE successfully receives 3 coded packets, it can successfully decode and recover the original data PDCP SDU1, PDCP SDU2 and PDCP SDU3, however, since the UE only receives PDCP PDU0 and PDCP PDU2, that is: the UE only successfully receives 2 coded packets (namely, system packet 1 and redundant packet 1), and can successfully decode and recover PDCP SDU1, PDCP SDU2 and PDCP SDU3 by 1 coded packet. The first information sent by the UE to the source base station at this time may include: information of 1 redundant packet is requested, information of 2 encoded packets is correctly received, or information of 2 encoded packets is not correctly received.

According to the first information, the source base station does not forward PDCP SDU1, PDCP SDU2 and PDCP SDU3 on the Xn interface, but forwards a second redundant packet obtained by the network coding function processing of this group of PDCP SDUs, for example: the forwarded second redundant packet is a redundant packet generated after the first information is received and the network coding function is processed according to the PDCP SDU1, the PDCP SDU2 and the PDCP SDU3, and is called as a redundant packet 3. Optionally, the redundant packet 3 is a redundant packet that is not yet sent by the source base station, and is different from both the redundant packet 1 and the redundant packet 2.

Optionally, in the above example, the first information may also be DDDS feedback (only applicable to the source base station adopting the CU-DU separation architecture) or an RLC status report, and the redundant packet 3 forwarded by the source base station on the Xn interface according to the first information is a second redundant packet that the UE has not successfully received or a redundant packet to be received by the UE. In this case, the first information may include information about the first data packet correctly received by the UE and/or information about the first data packet unsuccessfully received by the UE. For example, as shown in fig. 10, when the first information is DDDS feedback, the DDDS feedback may include information of successfully receiving PDCH PDU0 and PDCP PDU2, information of unsuccessfully receiving PDCP PDU1 and PDCP PDU3, and the like, and the source base station may know, according to the DDDS feedback, that the UE has not successfully received the redundant packet 2, and then the second redundant packet forwarded by the source base station to the target base station may be the redundant packet 2 (i.e., the redundant packet included in PDCP PDU 3).

b. In addition to forwarding the second redundant packet, the source base station may also forward PDCP SDUs to the target base station on an Xn interface.

Wherein, the PDCP SDUs forwarded by the Xn interface include PDCP SDUs that have not been processed by the PDCP layer of the source base station and/or PDCP SDUs that have been processed by the network coding function at the source base station but have not been sent to the UE. As shown in fig. 10, the source base station has not performed PDCP layer processing on the received PDCP SDU4, PDCP SDU5, and PDCP SDU6 (PDCP layer processing refers to at least one of associating PDCP SNs, header compression, ciphering/integrity protection processing, or adding a PDCP header), or the source base station performs processing with a network coding function on the received PDCP SDU4, PDCP SDU5, and PDCP SDU6 but has not generated a PDCP PDU, or the source base station performs processing with a network coding function on the received PDCP SDU4, PDCP SDU5, and PDCP SDU6 and adds a PDCP header to generate a PDCP PDU, but the generated PDCP PDU has not been sent to the UE, and then the source base station may send the PDCP SDU4, PDCP SDU5, and PDCP SDU6 to the target base station (target gsb-CU) through an Xn interface. For the example shown in fig. 10, the third packet may include PDCP PDU4 generated by the target base station.

Thus, in example 1, the source base station may forward the second redundant packet and PDCP SDUs to the target base station on an Xn interface. Wherein, for the second data packet of the redundant packet type, the target base station does not need to perform the processing of the network coding function, and for the PDCP SDU, the target base station needs to perform the processing of the network coding function. In order to enable the target base station to distinguish the type of the forwarding data received from the source base station, optionally, the source base station may send first indication information to the target base station, where the first indication information is used to indicate that the type of the second data packet is a redundant packet type. For example, when the second data packet sent by the source base station to the target base station includes a second redundant packet, the first indication information may be used to indicate that the type of the second data packet is a redundant packet type, and the target base station may ignore performing the network coding process on the second data packet.

Or, the first indication information may be used to indicate which forwarding data require the target base station to perform the processing of the network coding function, or indicate which forwarding data do not require the processing of the network coding function, and for a data packet that does not require the processing of the network coding function and is indicated by the first indication information, the target base station may ignore the processing of the network coding performed on the second data packet. For example, the first indication information is 1-bit indication information, which indicates that the target base station is required to perform the processing of the network coding function on the forwarding data when the value of the indication information is 0, and indicates that the target base station is not required to perform the processing of the network coding function on the forwarding data when the value of the indication information is 1.

For example, if data is forwarded to the target base station through the GTP tunnel on the Xn interface, the source base station may carry the first indication information in a GTP header field of the GTP tunnel. For example: and only when the source base station forwards the second redundant packet to the target base station, the GTP header field of the GTP tunnel carries the first indication information, and when the PDCP SDU is forwarded, the GTP header field of the GTP tunnel does not carry the first indication information. Alternatively, the identity of the GTP tunnel (e.g., GTP TEID) may be sent by the source sending device to the target sending device. Further, the source sending device sends a corresponding relationship to the target sending device, where the corresponding relationship includes a corresponding relationship between the identifier of the GTP tunnel and the first indication information, so that the target sending device knows that the first indication information is used to indicate whether the second packet needs to perform the network coding function. For example, the source sending device sends an XnAp message to the target sending device, where the first indication information corresponding to the identifier of the GTP tunnel and the identifier of the GTP tunnel may be carried, or the correspondence relationship is carried.

Optionally, the source base station may further send third indication information to the target base station, where the third indication information is used for the target base station to determine information of a first coding block that performs network coding function processing. Illustratively, the third indication information is a block Identifier (ID).

In a possible implementation manner, the third indication information may be used to indicate information of a first coding block performing network coding function processing on the target base station. As shown in fig. 10, the source base station performs one or more of the processes of dividing, cascading, and padding on PDCP SDU1, PDCP SDU2, and PDCP SDU3 to obtain a plurality of original data packets with equal size, and forms an encoding block from the original data packets, performs encoding operation and adds an encoding packet header to the encoding block to generate an encoding packet, where the encoding packet header of the generated encoding packet carries a corresponding encoding block identifier (block ID), for example: block ID 0, when the UE is switched, the source base station sends third indication information containing block ID1 to the target base station. And according to the indication information of the block ID1, the target base station executes the processing of the network coding function on the PDCP SDU4, the PDCP SDU5 and the PDCP SDU6 to generate a coding packet, and the coding packet head of the generated coding packet can carry the corresponding coding block identification block ID1. For the UE, the UE can only jointly decode the encoded packets belonging to the same block ID to ensure successful decoding, that is: the coded packets belonging to block ID 0 are subjected to combined decoding to recover PDCP SDU1, PDCP SDU2 and PDCP SDU3, and the coded packets belonging to block ID1 are subjected to combined decoding to recover PDCP SDU4, PDCP SDU5 and PDCP SDU6. If the target base station resets the coding block identifiers from the coding packets corresponding to the PDCP SDU4, 5 and 6, the coding block identifiers of the coding packets may collide with the coding block identifiers of the redundant packets from the source base station, resulting in a failure of decoding the UE.

In another possible implementation manner, the third indication information may be used to indicate information of a last coding block that performs network coding function processing on the source base station, and the target base station learns, according to the third indication information, a number of a first coding block that performs network coding function processing on the target base station. For example, as shown in fig. 10, one or more of the processes of splitting, cascading, padding, and the like of PDCP SDU1, PDCP SDU2, and PDCP SDU3 on the source base station obtain a plurality of original data packets with equal size, and form one coding block from the original data packets, perform coding operation and add a coding packet header to the coding block to generate a coding packet, where the coding packet header of the generated coding packet carries a corresponding coding block identifier, for example: block ID 0, when the UE is switched, the source base station sends third indication information containing the block ID 0 to the target base station. And according to the indication information of the block ID 0, the target base station executes the processing of the network coding function on the PDCP SDU4, the PDCP SDU5 and the PDCP SDU6 to generate a coding packet, and the coding packet head of the generated coding packet can carry a corresponding coding block identification block ID1. For the UE, the UE can only perform joint decoding on the encoded packets belonging to the same block ID to ensure successful decoding, that is: the coding packets belonging to the block ID 0 are jointly decoded to recover PDCP SDU1, PDCP SDU2 and PDCP SDU3, and the coding packets belonging to the block ID1 are jointly decoded to recover PDCP SDU4, PDCP SDU5 and PDCP SDU6.

For example, the third indication information may be carried in an existing SN status migration message, or the third indication information may also be carried in a GTP header field and sent together with the forwarding data.

In the above example 1, a scheme in which the source base station and the target base station transmit the coded packets to the UE before and after the handover is taken as an example (i.e., the method illustrated in fig. 7 (b), where the coded packets include systematic packets and redundant packets). Example 1 is also applicable to a scheme in which the source base station and the target base station transmit the original data packet and the redundant packet to the UE before and after the handover, respectively (i.e., the scheme illustrated in fig. 7 (a)), or other network coding schemes. In the scheme of sending the original data packet and the redundant packet to the UE by the source base station and the target base station before and after the handover, the system packet in the above description needs to be replaced by the original data packet, and the coded packet needs to be replaced by the original data packet and the redundant packet, which is not described herein again.

Example 2

In example 2, the source base station and the target base station both support the network coding function, and the network coding function is located in the PDCP layer. In addition, example 2 is described by taking as an example a scheme in which the source gNB-CU transmits the coded packet including the systematic packet and the redundant packet to the UE before the handover, and the target gNB-CU transmits the coded packet including the systematic packet and the redundant packet to the UE after the handover (i.e., the scheme illustrated in fig. 7 (b)).

In example 2, the second data packet includes a second PDCP SDU that the UE has not successfully recovered before handover, or that does not include a PDCP SDU that the UE successfully recovered from before handover. Specifically, the forwarding data in example 2 includes PDCP SDUs that have not been processed by the PDCP layer by the source base station, and/or includes second PDCP SDUs.

As shown in fig. 11, in example 2, the source base station may perform network coding function processing on the received PDCP SDU1, PDCP SDU2, and PDCP SDU3 to generate 4 coded packets (including 2 systematic packets and 2 redundant packets), and then add a PDCP header to the 4 coded packets to generate PDCP PDU0 (including systematic packet 1), PDCP PDU1 (including systematic packet 2), PDCP PDU2 (including redundant packet 1), and PDCP PDU3 (including redundant packet 2), that is, PDCP PDU0 to PDCP PDU3 serve as the first data packets. Because the UE only successfully receives the PDCP PDU0 and the PDCP PDU2, wherein the PDCP PDU0 comprises the system packet 1, and the system packet 1 comprises the complete PDCP SDU1, the UE can successfully recover the PDCP SDU1 through the received PDCP PDU 0. Assuming that the UE successfully receives 3 coded packets, it can successfully decode and recover the original data PDCP SDU1, PDCP SDU2 and PDCP SDU3, however, since the UE only receives PDCP PDU0 and PDCP PDU2, that is: the UE only successfully receives 2 coded packets (i.e., systematic packet 1 and redundant packet 1), and therefore, the UE cannot recover PDCP SDU2 and PDCP SDU3, and the first SDU is PDCP SDU2 and PDCP SDU3. The first information transmitted by the UE to the source base station at this time may include information of PDCP SDU1 successfully recovered by the UE or PDCP SDU2 and PDCP SDU3 not recovered by the UE.

Therefore, during the UE handover, the source gNB-CU forwards only PDCP SDU2 and PDCP SDU3 to the target gNB-CU, i.e. the second PDCP SDU comprises PDCP SDU2 and PDCP SDU3. In addition, the source gNB-CU may also forward PDCP SDU4, PDCP SDU5 and PDCP SDU6 to the target gNB-CU. The forwarding process of PDCP SDU4, PDCP SDU5, and PDCP SDU6 is the same as in example 1, and is not described here again. For the example shown in fig. 11, the third data packet may include PDCP PDU4 and PDCP PDU5 generated by the target base station.

It should be appreciated that although the target gNB-CU receives PDCP SDUs from the Xn interface, the processing is different for different PDCP SDUs. The target base station can obtain PDCP PDU4 and PDCP PDU5 shown in fig. 11 according to PDCP SDU2 and PDCP SDU3, while PDCP SDU4, PDCP SDU5 and PDCP SDU6 require the target base station to perform processing of the network coding function, and the PDCP PDUs obtained through the network coding processing include PDCP PDU6 to PDCP PDU9. In order to distinguish the processing modes of the PDCP SDUs by the target base station, there are two implementation modes:

as a possible implementation manner, when the source base station forwards data to the target base station, it needs to additionally indicate whether the PDCP SDU forwarded through the Xn interface needs to perform the processing of the network coding function, for example, the source base station sends second indication information to the target base station, where the second indication information is used to indicate whether the target base station performs the processing of the network coding function on the PDCP SDU forwarded through the Xn interface. The second indication information may be indication information that is displayed, for example, the second indication information is used for displaying processing that indicates whether to perform a network coding function on PDCP SDUs forwarded through the Xn interface. Alternatively, the second indication information may also be implicit indication information, such as: the second indication information is a block ID, and for the target base station, the network coding function is only performed on the forwarding PDCP SDUs carrying the second indication information, and the network coding function is not performed on the forwarding PDCP SDUs not carrying the second indication information. Optionally, the second indication information may be further configured to indicate whether the type of the second data packet is an SDU type, and if the second data packet is a second PDCP SDU, the second indication information may indicate that the type of the second data packet is an SDU type, and accordingly, when the second indication information indicates that the type of the second data packet is an SDU type, the target base station does not need to perform processing of the network coding function on the second data packet.

Illustratively, the second indication information may be carried in a GTP header field of the Xn interface. For example, as shown in fig. 11, when the source gNB-CU forwards PDCP SDU2 and PDCP SDU3 to the target gNB-CU, the source gNB-CU carries second indication information in the GTP header field to indicate that the PDCP SDU2 and PDCP SDU3 do not need to perform the processing of the network coding function on the target base station, and when the source gNB-CU forwards PDCP SDU4, PDCP SDU5, and PDCP SDU6 to the target gNB-CU, the source gNB-CU carries second indication information in the GTP header field to indicate that the PDCP SDU4, PDCP SDU5, and PDCP SDU6 need to perform the processing of the network coding function on the target base station.

Or when the source gNB-CU forwards PDCP SDU2 and PDCP SDU3 to the target gNB-CU, the source gNB-CU carries second indication information in a GTP header field to indicate that the PDCP SDU2 and PDCP SDU3 do not need to execute the processing of the network coding function on the target base station, and when the source gNB-CU forwards PDCP SDU4, PDCP SDU5 and PDCP SDU6 to the target gNB-CU, the second indication information is not carried in the GTP header field, the target base station executes the processing of the network coding function by default on the PDCP SDU4, PDCP SDU5 and PDCP SDU6 which do not carry the second indication information.

Or when the source gNB-CU forwards PDCP SDU2 and PDCP SDU3 to the target gNB-CU, the second indication information is not carried in the GTP header field, the target base station does not execute the processing of the network coding function by default on the PDCP SDU2 and PDCP SDU3 which do not carry the second indication information, and when the source gNB-CU forwards PDCP SDU4, PDCP SDU5 and PDCP SDU6 to the target gNB-CU, the second indication information is carried in the GTP header field to indicate that the PDCP SDU4, PDCP SDU5 and PDCP SDU6 need to execute the processing of the network coding function on the target base station.

Optionally, the second indication information may indicate information of a starting PDCP SDU performing network coding function processing at the target base station. Illustratively, the information of the starting PDCP SDU includes a SN number corresponding to the PDCP SDU. For example, as shown in fig. 11, the target base station starts to perform the processing of the network coding function from PDCP SDU4, and the second indication information includes an SN number corresponding to PDCP SDU4, the target base station does not need to perform the processing of the network coding function on PDCP SDU2 and PDCP SDU3.

Optionally, similar to the third indication information sent by the source base station to the target base station in example 1, the source base station may further send the third indication information to the target base station in example 2, where the third indication information is used for the target base station to determine information of the first coding block for performing the network coding function processing. The implementation manner of the third indication information may refer to the implementation manner of the third indication information in example 1, and is not described herein again. For example, the third indication information may be used to indicate the number of the first coding block performing network coding function processing on the target base station, or the third indication information may be used to indicate the number of the last coding block performing network coding function processing on the source base station.

In example 2, since the PDCP PDUs received by the UE from the target base station include PDCP PDUs (e.g., PDCP PDU6 to PDCP PDU9 shown in fig. 11) processed by the network coding function and PDCP PDUs (e.g., PDCP PDU4 and PDCP PDU5 shown in fig. 11) not processed by the network coding function, in order for the UE to distinguish the received PDCP PDUs, the target base station needs to send fifth indication information to the UE, where the fifth indication information is used to indicate whether the PDCP PDUs are processed by the network coding function or not, or to indicate whether the PDCP PDUs need to be subjected to network decoding, so that the UE performs different processing on the received PDCP PDUs.

Optionally, the fifth indication information may be a displayed indication, that is: displaying and indicating whether the PDCP PDU is processed by a network coding function or not, or displaying and indicating whether the PDCP PDU needs to execute the processing of network decoding or not; or, the fifth indication information may be an implicit indication, that is: indicating that the effective payload of the PDCP PDU carries a coding packet or a PDCP SDU.

For example, the target base station may add indication information (i.e., fifth indication information) in the PDCP header field for indicating whether the PDCP PDU needs to be decoded by the network. The fifth indication information may be 1-bit information, for example, when the value of the 1-bit information is 0, the fifth indication information is used to indicate that the PDCP PDU needs to perform the network decoding process, and when the value of the 1-bit information is 1, the fifth indication information is used to indicate that the PDCP PDU does not need to perform the network decoding process. Taking fig. 11 as an example, the target base station does not perform the processing of the network coding function on the PDCP SDU2 and the PDCP SDU3, and may continue to use the existing mechanism to generate the corresponding PDCP PDU4 and PDCP PDU5 after the PDCP SDU2 and the PDCP SDU3 are processed by the PDCP layer, and send the generated PDCP PDU4 and PDCP PDU5 to the UE, where the PDCP PDU4 and PDCP PDU5 may carry fifth indication information indicating that the processing of the network coding function is not performed. The target base station can also generate coding packets for the PDCP SDU4, the PDCP SDU5 and the PDCP SDU6 after the processing of network coding, then the coding packets are added with PDCP header operation to generate corresponding PDCP PDU6 to PDCP SDU9 and are sent to the UE, the PDCP PDU6 to PDCP SDU9 can carry fifth indication information indicating the processing of the network coding function, correspondingly, the UE can know whether the received PDCP PDU needs to execute the processing of network coding according to the fifth indication information carried in the PDCP header field, if the indication does not need to execute the processing of network coding, the UE directly restores the PDCP PDU to the corresponding PDCP SDU by using the existing mechanism, and if the indication needs to execute the processing of network coding, the UE restores the PDCP PDU to the corresponding PDCP SDU after the processing of the network coding function.

For example, the UE receives PDCP PDU4 and PDCP PDU5 sent by the target base station, where fifth indication information carried in the PDCP header field indicates that the PDCP PDU4 and PDCP PDU5 do not need to perform network decoding processing, and also receives PDCP PDU6 to PDCP SDU9 sent by the target base station, where fifth indication information carried in the PDCP header fields of the PDCP PDU6 to PDCP SDU9 indicates that the PDCP PDU needs to perform network decoding processing.

Or, the UE receives PDCP PDU4 and PDCP PDU5 sent by the target base station, wherein if the PDCP header field does not carry the fifth indication information, the UE defaults that the PDCP PDU4 and PDCP PDU5 do not need to perform network decoding; and the UE receives PDCP PDU6 to PDCP SDU9 sent by the target base station, wherein if fifth indication information carried in PDCP header fields of the PDCP PDU6 to PDCP SDU9 indicates that the network decoding processing needs to be executed, the UE needs to execute the network decoding processing on the PDCP PDU6 to PDCP SDU 9.

Or, the UE receives the PDCP PDU4 and PDCP PDU5 sent by the target base station, wherein the fifth indication information carried in the PDCP header field, so that the UE does not need to perform network decoding processing on the PDCP PDU4 and PDCP PDU 5; and the UE receives PDCP PDU6 to PDCP SDU9 sent by the target base station, wherein if the PDCP header fields of the PDCP PDU6 to PDCP SDU9 do not carry the fifth indication information, the UE defaults that the PDCP PDU6 to PDCP SDU9 need to execute the processing of network decoding.

Optionally, the UE may further determine whether network decoding processing needs to be performed on the PDCP PDU from the target base station according to the size of the PDCP PDU received from the target base station. Because the sizes of different coded packets are the same, the sizes of the PDCP PDUs after the PDCP packet headers are respectively added to the different coded packets are also the same, but the sizes of the PDCP SDUs are generally different, so that the sizes of the PDCP PDUs directly generated by the different PDCP SDUs are different. If the sizes of the PDCP PDUs received by the UE are the same, the UE may consider that the payload of the PDCP PDU carries an encoded packet, and needs to perform network decoding on the PDCP PDU. If the UE receives PDCP PDUs with the same size and receives other PDCP PDUs with sizes different from the PDCP PDUs, it may be considered that PDCP SDUs are carried in the payload of the other PDCP PDUs, and the UE does not need to perform network decoding on the other PDCP PDUs but still needs to perform network decoding on the PDCP PDUs with the same size.

Example 2 is described by taking as an example a scheme in which the source base station and the target base station transmit coded packets including systematic packets and redundant packets to the UE before and after handover, respectively (i.e., the method illustrated in fig. 7 (b)). Example 2 is also applicable to a scheme (i.e., the scheme illustrated in fig. 7 (a)) in which the source base station and the target base station transmit the original data packet and the redundant packet to the UE before and after the handover, respectively, or other network coding schemes. In the scheme of sending the original data packet and the redundant packet to the UE by the source base station and the target base station before and after the handover, the system packet in the above description needs to be replaced by the original data packet, and the coded packet needs to be replaced by the original data packet and the redundant packet, which is not described herein again.

Example 3

In example 3, the source base station and the target base station both support the network coding function, and the network coding function is located in the PDCP layer. In addition, example 3 is described taking as an example a scheme in which the source gNB-CU transmits the coded packet including the systematic packet and the redundant packet to the UE before the handover, and the target gNB-CU transmits the coded packet including the systematic packet and the redundant packet to the UE after the handover (i.e., the scheme illustrated in fig. 7 (b)).

In example 3, the second data packet includes a set of PDCP SDUs corresponding to the same coding block. Optionally, at least one PDCP SDU in the group of PDCP SDUs is unrecovered by the UE before handover from a packet received from the source base station, or the group of PDCP SDUs includes a second PDCP SDU. At this time, the source base station may forward PDCP SDUs to the target base station on an Xn interface, wherein the PDCP SDUs forwarded through the Xn interface include PDCP SDUs that have not been processed by the PDCP layer of the source base station and/or the set of PDCP SDUs.

As shown in fig. 12, the source base station performs one or more of segmentation, concatenation, and padding on received PDCP SDU1, PDCP SDU2, and PDCP SDU3 to obtain a plurality of original data packets with equal size, and forms an encoding block from the original data packets to perform encoding operation and add packet headers of the encoding packets to generate 4 encoding packets (including 2 system packets and 2 redundant packets), and then adds PDCP headers to the 4 encoding packets to generate PDCP PDU0 (including system packet 1), PDCP PDU1 (including system packet 2), PDCP PDU2 (including redundant packet 1), and PDCP PDU3 (including redundant packet 2), that is, the first data packet includes PDCP PDU0 to PDCP PDU3. Wherein the coding block corresponds to PDCP SDU1, PDCP SDU2 and PDCP SDU3. Because the UE only successfully receives the PDCP PDU0 and the PDCP PDU2, wherein the PDCP PDU0 comprises a system packet 1, and the system packet 1 comprises a complete PDCP SDU1, the UE can successfully recover the PDCP SDU1 through the received PDCP PDU 0. Assuming that the UE successfully receives 3 coded packets, it can successfully decode and recover the original data PDCP SDU1, PDCP SDU2 and PDCP SDU3, however, since the UE only receives PDCP PDU0 and PDCP PDU2, that is: the UE only successfully receives 2 coded packets (i.e., systematic packet 1 and redundant packet 1), and therefore, the UE cannot recover PDCP SDU2 and PDCP SDU3, i.e.: the UE has not successfully decoded and recovered all PDCP SDUs corresponding to the coding block. Therefore, in the UE handover process, the source gNB-CU needs to forward PDCP SDU1, PDCP SDU2, and PDCP SDU3 to the target gNB-CU, and the target base station can generate PDCP PDUs 0 to 3 through the processing of the network coding function according to PDCP SDU1, PDCP SDU2, and PDCP SDU3. In addition, the source gNB-CU also needs to forward PDCP SDU4, PDCP SDU5 and PDCP SDU6 to the target gNB-CU, and the target base station can generate PDCP PDUs 4 to 7 according to the processing of the PDCP SDU4, PDCP SDU5 and PDCP SDU6 by the network coding function. The forwarding process of PDCP SDU4, PDCP SDU5, and PDCP SDU6 is the same as in example 1, and is not described here again. It is to be understood that, for the example shown in fig. 12, the third packet may include PDCP PDUs 0 to 3 generated by the target base station.

For the UE, before handover, PDCP SDU1 can be successfully recovered from PDCP PDU0 sent by the source base station. After the switching, the UE successfully recovers PDCP SDU1, PDCP SDU2 and PDCP SDU3 according to PDCP PDU 0-PDCP PDU3 sent by the target base station. In order to avoid the duplicate delivery of the data packets (i.e. avoid the PDCP layer of the UE repeatedly delivering the PDCP SDU1 to the upper layer), the UE needs to delete the data related to the coding blocks corresponding to the PDCP SDU1, PDCP SDU2 and PDCP SDU3 received from the source base station, including the UE deleting at least one of the following data: and the UE recovers the PDCP SDU from the PDCP PDU received from the source base station, the PDCP PDUs corresponding to the PDCP SDU1, the PDCP SDU2 and the PDCP SDU3 received from the source base station by the UE, or the coding packets contained in the PDCP PDUs corresponding to the PDCP SDU1, the PDCP SDU2 and the PDCP SDU3 received from the source base station by the UE. The PDCP SDU recovered by the UE according to the PDCP PDU received from the source base station may be a PDCP SDU directly recovered from the PDCP PDU, or a PDCP SDU recovered by decoding an encoded packet included in the PDCP PDU.

As shown in fig. 12, the UE deletes at least one of the following data: PDCP SDU1 recovered from PDCP PDU0 received from the source base station, PDCP PDU0 and PDCP PDU2 received from the source base station, and system packet 1 corresponding to PDCP PDU0 received from the source base station and redundant packet 1 corresponding to PDCP PDU2.

Optionally, the UE may receive an indication information (which may be referred to as a fourth indication information) that may be used to instruct the UE to delete data that overlaps all or part of the data in a group of PDCP SDUs. For example, the fourth indication information may be used to indicate at least one of a duplicate PDCP PDU that needs to be deleted by the UE, an encoded packet corresponding to the PDCP PDU, or a PDCP SDU recovered by a system packet and/or a redundant packet corresponding to the PDCP PDU. The indication information may be generated by the source base station or generated by the target base station. Illustratively, the fourth indication information may be carried in an RRC message.

As a possible implementation manner, the fourth indication information includes a block ID (or a block ID list), and the UE may determine, according to the indication information, the coding packet that needs to be deleted. For example, the block ID carried in the coding packets needs to be deleted and is less than or equal to the block ID carried in the indication information, so that the UE deletes the coding packets, the PDCP SDUs successfully recovered by the coding packets, or at least one of the PDCP PDUs corresponding to the coding packets.

As another possible implementation, the fourth indication information includes a PDCP SN (or a PDCP SN list). The UE may determine PDCP PDUs to be deleted according to the indication information, where the deleted PDCP PDUs include PDCP PDUs corresponding to the SN received from the source base station, so that the UE may delete at least one of the PDCP PDUs, encoded packets corresponding to the PDCP PDUs, or PDCP SDUs successfully recovered through the encoded packets.

As another possible implementation manner, the fourth indication information includes start PDCP SN information and a bitmap (bitmap). The starting PDCP SN is used for indicating the first PDCP PDU which needs to be deleted by the UE from the PDCP PDUs received from the source base station, and the bitmap can be used for indicating the PDCP PDUs which need to be deleted and are positioned behind the starting PDCP PDU. The UE may then delete at least one of the PDCP PDUs, the encoded packets corresponding to the PDCP PDUs, or the PDCP SDUs successfully recovered from the encoded packets.

As another possible implementation, the fourth indication information includes start PDCP SN and termination PDCP SN information. The starting PDCP SN is used for indicating the first PDCP PDU which needs to be deleted by the UE from the PDCP PDUs received from the source base station, and the ending PDCP SN is used for indicating the last PDCP PDU which needs to be deleted by the UE from the PDCP PDUs received from the source base station. After receiving the indication information, the UE deletes all PDCP PDUs from the first PDCP PDU to the last PDCP PDU received from the source base station. The UE may then delete at least one of the PDCP PDUs, the encoded packets corresponding to the PDCP PDUs, or the PDCP SDUs successfully recovered from the encoded packets.

As shown in fig. 12, the source base station performs one or more of the processing of dividing, cascading, and padding on PDCP SDU1, PDCP SDU2, and PDCP SDU3 to obtain a plurality of original data packets with equal size, and forms an encoding block from the original data packets to perform encoding operation and add an encoding packet header to generate an encoding packet, where the encoding packet carries fourth indication information, and the fourth indication information indicates block ID =0. And the source base station generates a PDCP PDU after adding a PDCP header to the coded packet and sends the PDCP PDU to the UE. The UE successfully receives the PDCP PDU0 and the PDCP PDU2 transmitted by the source base station. The UE deletes at least one of the following data according to the fourth indication information:

PDCP PDU0 and PDCP PDU2; or,

a system packet 1 corresponding to the PDCP PDU0 and a redundant packet 1 corresponding to the PDCP PDU2; or,

and 3.PDCP SDU1 recovered by PDCP PDU0.

Example 4

Similar to example 3, in this embodiment, the source base station forwards PDCP SDUs to the target base station on an Xn interface, where the PDCP SDUs forwarded through the Xn interface include PDCP SDUs that have not been processed by the PDCP layer by the source base station, and/or a group of PDCP SDUs corresponding to the same coding block. In example 4, the second data packet is a group of PDCP SDUs corresponding to the same coding block, at least one PDCP SDU in the group of PDCP SDUs not recovered by the UE from a data packet received from the source base station before handover, or the group of PDCP SDUs includes the second PDCP SDU.

The difference from example 3 is that in example 4, the PDCP SDU sent by the source base station to the UE and the PDCP SDU forwarded by the source base station to the target base station carry an identifier (which may be referred to as a first sequence number) for identifying the PDCP SDU, that is: the source base station may be considered to form a PDCP SDU 'by the PDCP SDU and the corresponding first sequence number, and send the PDCP SDU' to the UE after being processed as the PDCP SDU, and forward the PDCP SDU 'to the target base station on the Xn interface, and the target base station obtains the PDCP PDU according to the PDCP SDU' and forwards the PDCP PDU to the UE, so that the UE carries the first sequence number according to the PDCP SDU obtained from the PDCP PDU of the target base station. The first sequence number may then be represented by SN', i.e.: the PDCP SDU 'is composed of PDCP SDU and SN'. The UE may identify whether the PDCP SDU 'from the target base station and the PDCP SDU' from the source base station are duplicated according to the SNs ', and delete the duplicated PDCP SDUs' if the UE obtains the duplicated PDCP SDUs 'from the source base station and the target base station, respectively, to avoid the UE submitting the duplicated PDCP SDUs' to an upper layer. It can be seen that the UE need not be instructed by the fourth indication information in this example which data to delete.

Optionally, there are two possible implementations in example 4:

as a possible implementation manner, as shown in fig. 13, the source base station may add a header field for each PDCP SDU to carry the associated SN 'of the SDU, and generate a PDCP SDU'. The source base station forwards the PDCP SDU' to the target base station through the GTP tunnel. After receiving the PDCP SDU ', the target base station processes the PDCP SDU' by adopting the existing PDCP SDU processing mechanism and sends data to the UE. The UE performs duplicate packet detection based on the SNs 'carried in the PDCP SDUs' from the source and target base stations, respectively. Duplicate PDCP SDUs ' may be deleted if the UE finds that the SN ' carried in the PDCP SDU ' from the source base station is the same as the SN ' carried in the PDCP SDU ' from the target base station. Wherein for the example shown in fig. 13, the third data packet may include PDCP PDUs 0 to 3 generated by the target base station.

As another possible implementation manner, as shown in fig. 14, the source base station encapsulates the PDCP SDU in a GTP tunnel and sends the GTP tunnel to the target base station, and carries the SN' corresponding to the PDCP SDU in the GTP header field. The target base station extracts PDCP SDU and corresponding SN ' from the GTP tunnel, and sends data to the UE by adopting the existing PDCP SDU processing mechanism after generating the PDCP SDU ' by the PDCP SDU and the corresponding SN '. The UE performs duplicate packet detection based on the SNs 'carried in the PDCP SDUs' from the source and target base stations, respectively. The UE can identify the PDCP SDU from the source base station and the repeated PDCP SDU in the PDCP SDU from the target base station according to the value of the SN ', and if the SN' carried in the GTP header field of the PDCP SDU from the source base station is found to be the same as the SN 'carried in the GTP header field of the PDCP SDU' from the target base station, the PDCP SDU can be deleted. Wherein for the example shown in fig. 14, the third data packet may include PDCP PDUs 0 to 3 generated by the target base station.

Examples 3 and 4 above illustrate an example of a scheme in which the source base station and the target base station transmit coded packets including systematic packets and redundant packets to the UE, respectively, before and after handover (i.e., the method illustrated in fig. 7 (b)). Examples 3 and 4 are also applicable to a scheme (i.e., the scheme illustrated in fig. 7 (a)) in which the source base station and the target base station transmit the original data packet and the redundant packet to the UE before and after the handover, respectively, or other network coding schemes. In the scheme of sending the original data packet and the redundant packet to the UE by the source base station and the target base station before and after the handover, the system packet in the above description needs to be replaced by the original data packet, and the coded packet needs to be replaced by the original data packet and the redundant packet, which is not described herein again.

Example 5

In example 5, the source base station supports the network coding function, but the target base station does not support the network coding function. Example 5 illustrates a network coding function located above the PDCP layer, for example, the network coding function is located in a protocol layer newly introduced between the PDCP layer and the SDAP layer, or the network coding function is located in the SDAP layer, or the network coding function is located above the SDAP layer. In addition, example 5 is described taking as an example a scheme in which the pre-handover source gNB-CU transmits encoded packets including systematic packets and redundant packets to the UE (i.e., the method illustrated in fig. 7 (b)).

In this embodiment, since the network coding function is located above the PDCP layer, the PDCP SDU received by the source base station has been processed by the network coding function. In addition, in example 5, the second data packet sent by the source base station to the target base station through the Xn interface in the UE handover process is PDCP SDU that the UE has not successfully received, so that the PDCP SDU forwarded through the Xn interface is processed by the network coding function, and the target base station performs PDCP layer processing on the PDCP SDU that the UE has not successfully received, generates PDCP PDU and sends the PDCP PDU to the UE. In addition, because the target base station does not support the processing of the network coding function, the target base station does not process the PDCP SDUs received from the core network by the network coding function, and the target base station performs PDCP layer processing on the PDCP SDUs to generate PDCP PDUs and sends the PDCP PDUs to the UE.

As shown in fig. 15, if the UE indicates to the source base station through the first information that PDCP SDU2 and PDCP SDU3 are not received, the S-gbb-CU may transmit PDCP SDU2 and PDCP SDU3 to the T-gbb-CU. As shown in fig. 15, the third data packet in this example includes PDCP PDUs obtained from PDCP SDU2 and PDCP SDU3.

For the UE, there are two kinds of processing for the PDCP SDUs received from the target base station, the network decoding processing needs to be performed on the PDCP SDUs that are processed by the network coding function, and the network decoding processing does not need to be performed on the PDCP SDUs that are not processed by the network coding function, so that the UE needs to distinguish the two kinds of PDCP SDUs received from the target base station, and at this time, the target base station may send fifth indication information to the UE, and the implementation manner of the fifth indication information may refer to the description of the fifth indication information in example 2, and is not described herein again. According to the fifth indication information, when the network coding function is executed by the first protocol layer higher than the second protocol layer, the receiving device may learn whether the PDCP PDU is subjected to the network coding processing according to the fifth indication information, so as to determine whether to execute the decoding processing corresponding to the network coding on the PDCP PDU, so as to correctly receive the data in the third data packet. The decoding process of the PDCP PDU comprises the step of decoding the PDCP SDU after the PDCP SDU is obtained according to the PDCP PDU.

The present embodiment is also applicable to a scenario where the network coding function is located in the PDCP layer, that is, the source base station supports the network coding function, and the target base station does not support the network coding function, for example, in the Xn interface data forwarding manner described in example 1, the source base station forwards the redundant packet to the target base station at the Xn interface, and the PDCP SDU received by the target base station from the core network generates a PDCP PDU without being processed by the network coding function, and sends the PDCP PDU to the UE. In this case, the UE also needs to distinguish the two PDCP SDUs received from the target base station, and the target base station needs to send the fifth indication information to the UE.

Example 5 illustrates a scheme in which the UE receives the coded packet (i.e., the method illustrated in fig. 7 (b), where the coded packet includes a systematic packet and a redundant packet). The embodiment is also applicable to a scheme (i.e., the scheme illustrated in fig. 7 (a)) in which the UE receives the original data packet and the redundant packet or other network coding schemes, and the specific implementation manner may refer to the implementation manner of the scheme in which the UE receives the coded packet, and is not described again. In the scheme for receiving the original data packet and the redundant packet by the UE, the coded packet in the above description needs to be replaced by the original data packet and the redundant packet, which is not described herein again.

In addition, in the present application, in the case that the source base station and the target base station both support the network coding function, during the UE handover preparation process, the source base station may further send related information such as configuration information (including network coding related parameter information) of the network coding function to the target base station, so that the target base station uses the information to perform processing of the network coding function. Specifically, the network coding related parameter information may include at least one of a network coding type, a size of a coding block, a size of a systematic packet, a size of an original data packet, a number of systematic packets, a number of original data packets, a number of redundant packets, a selection of coding coefficients, or a convolution depth. If the source base station and the target base station use the same parameters to perform the processing of the network coding function, the UE may use the same set of parameters to decode the coded packets from the source base station and the target base station, respectively, so as to improve the decoding efficiency.

Optionally, the target base station may send sixth indication information to the source base station, where the sixth indication information is used to indicate whether the target base station supports the network coding function. The source base station and the target base station may implement any one of example 1 to example 4 above if the target base station supports the network coding function. If the target base station does not support the network coding function, the source base station and the target base station may implement the scheme shown in example 5 above.

Based on the same inventive concept, the embodiments of the present application further provide a communication apparatus, configured to implement the above functions implemented by the source sending device, the receiving device, and/or the target sending device. The device may include the structure shown in fig. 16 and/or fig. 17.

As shown in fig. 16, a communication device provided in an embodiment of the present invention may include a transceiver module 1620 and a processing module 1610, where the transceiver module 1620 and the processing module 1610 are coupled to each other. The communications apparatus may be configured to perform the steps performed by any one or more of the source transmitting device (or source base station), the receiving device (or UE), or the target transmitting device (or target base station) shown in fig. 9-15 above. In particular, the transceiver module 1620 can be used to support communication of a communication device, and the transceiver module 1620 can also be referred to as a communication unit, a communication interface, a transceiver module, or a transceiver unit. The transceiver module 1620 may have a wireless communication function, for example, to communicate with the UE through a wireless communication method, and may have a wired communication function, for supporting the communication device to communicate through a wired communication interface (e.g., xn interface). The processing module 1610 may be configured to enable the communication apparatus to perform the steps performed by any one or more of the source sending device, the receiving device, or the target sending device shown in the above method embodiments, and some steps not shown in the above embodiments, the steps including, but not limited to: generate information and messages to be transmitted by the transceiver module 1620, and/or perform demodulation and decoding processing on signals received by the transceiver module 1620.

When the source transmitting device provided in the embodiment of the present application is implemented by the structure shown in fig. 16, the transceiver module 1620 may be configured to transmit a first data packet to a receiving device. The transceiver module 1620 may also receive the first information from the receiving device. The transceiver module 1620 may further transmit the second data packet to the target transmission apparatus according to the first information.

In one possible example, the transceiver module 1620 may be further configured to transmit at least one of: the first indication information to the fourth indication information, the configuration information of the network coding function, or the first indication information corresponding to the GTP tunnel and used for sending the identifier of the GTP tunnel carrying the second data packet.

In one possible example, the transceiver module 1620 may be further configured to receive at least one of: the first information or the sixth indication information.

When the receiving device provided in this embodiment of the present application is implemented by the structure shown in fig. 16, the transceiver module 1620 may be configured to receive a first data packet from a source transmitting device and transmit first information. The transceiver module 1620 may also be configured to receive a third data packet from the target transmitting device.

In one possible example, the transceiver module 1620 may be further configured to receive at least one of: fourth indication information or fifth indication information.

When the target transmission device provided in the embodiment of the present application is implemented by the structure shown in fig. 16, the transceiver module 1620 may be configured to receive the second data packet from the source transmission device and transmit the third data packet. The transceiver module 1620 may be further configured to receive a third data packet from the target sending device, and/or receive an identifier of a GTP tunnel carrying the second data packet and first indication information corresponding to the identifier of the GTP tunnel.

In one possible example, the transceiver module 1620 may be further configured to transmit a sixth indication information.

In one possible example, the transceiver module 1620 may be further configured to receive at least one of: the first indication information to the fourth indication information, or the configuration information of the network coding function.

It should be understood that various terms appearing in the device embodiments and details of various possible implementations may be referred to in the description or explanation of the method embodiments above, and are not repeated here.

Fig. 17 is a schematic structural diagram of another communication apparatus for performing actions performed by at least one of a source sending device, a receiving device, or a target sending device according to an embodiment of the present application. As shown in fig. 17, the communication device may include a processor and a memory. The processor is mainly used for processing a communication protocol and communication data, controlling the communication device, executing a software program, processing data of the software program, and the like. The memory is used primarily for storing software programs and data. The communication interface is mainly used for communication between the source sending device and the target sending device.

The above communication apparatus may further include an antenna and a radio frequency circuit for performing communication by wireless communication, for example, the source transmission device or the target transmission device may transmit data to the receiving device through the antenna and the radio frequency circuit, and the receiving device may receive data through the antenna and the radio frequency circuit. When data (or information and signals) need to be sent, the processor of the communication device can also perform baseband processing on the data to be sent, and outputs baseband signals to the radio frequency circuit, and the radio frequency circuit performs radio frequency processing on the baseband signals and then sends the radio frequency signals to the outside in the form of electromagnetic waves through the antenna. When data (or information and signals) are transmitted to the communication device, the radio frequency circuit receives radio frequency signals through the antenna, converts the radio frequency signals into baseband signals and outputs the baseband signals to the processor, and the processor converts the baseband signals into data and processes the data.

In the embodiment of the present application, an antenna and/or a radio frequency circuit having a transceiving function may be regarded as a transceiving unit of a communication device. The transceiving unit may further comprise a communication interface or the like. The transceiving unit may be a functional unit that is capable of performing a transmitting function and a receiving function; alternatively, the transceiver unit may include two functional units, namely, a receiver unit capable of implementing a receiving function and a transmitter unit capable of implementing a transmitting function. A processor having processing functionality may also be considered a processing unit of a communication device. As shown in fig. 17, the communication device may include a transceiving unit 1710 and a processing unit 1720. A transceiver unit may also be referred to as a transceiver, a transceiving device, etc. A processing unit may also be referred to as a processor, a processing board, a processing module, a processing device, or the like. Optionally, a device for implementing the receiving function in the transceiving unit 1710 may be regarded as a receiving unit, and a device for implementing the transmitting function in the transceiving unit 1710 may be regarded as a transmitting unit, that is, the transceiving unit 1710 includes a receiving unit and a transmitting unit. A transceiver unit may also sometimes be referred to as a transceiver, transceiver circuit, or the like. A receiving unit may also be referred to as a receiver, a receiving circuit, or the like. A transmitting unit may also sometimes be referred to as a transmitter, or a transmitting circuit, etc.

It is understood that the transceiving unit 1710 may correspond to the transceiving module 1620, or the transceiving module 1620 may be implemented by the transceiving unit 1710. The transceiving unit 1710 is configured to perform a transmitting operation and a receiving operation of at least one of a source transmitting device, a receiving device, or a target transmitting device in the embodiments illustrated in the present application, and/or other processes for supporting the techniques described herein. The processing unit 1720 may correspond to the processing module 1610, or the processing module 1610 may be implemented by the processing unit 1720. The processing unit 1720 is configured to perform operations other than transceiving operations for at least one of a source transmitting device, a receiving device, or a target transmitting device of the embodiments illustrated herein, e.g., to perform all operations except receiving and transmitting performed by at least one of the source transmitting device, the receiving device, or the target transmitting device of the embodiments illustrated herein, and/or to support other processes for the techniques described herein.

That is, the actions performed by the processing module 1610 in the above example can be performed by the processing unit 1720 shown in fig. 17, and are not described again. Likewise, the actions performed by the transceiver module 1620 may be performed by the transceiver 1710 shown in fig. 17.

For ease of illustration, only one memory and processor are shown in FIG. 17. In an actual communication device, there may be one or more processors and one or more memories. The memory may also be referred to as a storage medium or a storage device, etc. The memory may be provided independently of the processor, or may be integrated with the processor, which is not limited in this embodiment.

It is understood that in this application, "when 8230, if" and "if" all refer to a device that performs the corresponding process in an objective manner, and are not intended to be limiting in time, nor do they require certain judgment actions to be taken in the implementation of the device, nor do they imply other limitations.

The term "simultaneously" in this application is to be understood as meaning at the same point in time, within a period of time, within the same period of time, and in particular in conjunction with the context.

It is understood that in the embodiments of the present application, "B corresponding to a" means that B is associated with a. "determining B from a" does not mean determining B from a alone, but may also determine B from a and/or other information.

The correspondence shown in the tables in the present application may be configured or predefined. The values of the information in each table are merely examples, and may be configured as other values, which is not limited in the present application. When the correspondence between the information and each parameter is configured, it is not always necessary to configure all the correspondences indicated in each table. For example, in the table in the present application, the correspondence shown in some rows may not be configured. For another example, appropriate modification adjustments, such as splitting, merging, etc., can be made based on the above tables. The names of the parameters in the tables may be other names understandable by the communication device, and the values or the expression of the parameters may be other values or expressions understandable by the communication device. When the above tables are implemented, other data structures may be used, for example, arrays, queues, containers, stacks, linear tables, pointers, linked lists, trees, graphs, structures, classes, heaps, hash tables, or the like may be used.

Predefinition in this application may be understood as defining, predefining, storing, pre-negotiating, pre-configuring, curing, or pre-firing.

In the embodiment of the present application, it should be noted that the above method embodiments of the present application may be applied to a processor, or may be implemented by a processor. The processor may be an integrated circuit chip having signal processing capabilities. In implementation, the steps of the above method embodiments may be performed by integrated logic circuits of hardware in a processor or instructions in the form of software. The processor may be a general purpose processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), an array of Field Programmable Gates (FPGA) or other programmable logic devices, discrete gate or transistor logic, or discrete hardware components. The various methods, steps, and logic blocks disclosed in the embodiments of the present application may be implemented or performed. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like. The steps of the method disclosed in connection with the embodiments of the present application may be directly implemented by a hardware decoding processor, or implemented by a combination of hardware and software modules in the decoding processor. The software module may be located in ram, flash memory, rom, prom, or eprom, registers, etc. storage media as is well known in the art. The storage medium is located in a memory, and a processor reads information in the memory and completes the steps of the method in combination with hardware of the processor.

It will be appreciated that the memory in the embodiments of the subject application can be either volatile memory or nonvolatile memory, or can include both volatile and nonvolatile memory. The non-volatile memory may be a read-only memory (ROM), a Programmable ROM (PROM), an Erasable PROM (EPROM), an Electrically Erasable PROM (EEPROM), or a flash memory. Volatile memory can be Random Access Memory (RAM), which acts as external cache memory. By way of example, but not limitation, many forms of RAM are available, such as Static Random Access Memory (SRAM), dynamic Random Access Memory (DRAM), synchronous Dynamic Random Access Memory (SDRAM), double data rate SDRAM, enhanced SDRAM, SLDRAM, synchronous Link DRAM (SLDRAM), and direct rambus RAM (DR RAM). It should be noted that the memory of the systems and methods described herein is intended to comprise, without being limited to, these and any other suitable types of memory.

The methods provided by the above embodiments may be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented in software, may be implemented in whole or in part in the form of a computer program product. The computer program product may include one or more computer instructions. When loaded and executed on a computer, cause the processes or functions described in accordance with the embodiments of the application to occur, in whole or in part. The computer may be a general purpose computer, a special purpose computer, a network of computers, or other programmable device. The computer instructions may be stored in a computer readable storage medium or transmitted from one computer readable storage medium to another computer readable storage medium, for example, the computer instructions may be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, digital Subscriber (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device, such as a server, a data center, etc., that includes one or more available media. The usable medium may be a magnetic medium (e.g., a floppy disk, a hard disk, a magnetic disk), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., a Solid State Disk (SSD)), among others.

Those of ordinary skill in the art will appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application.

It can be clearly understood by those skilled in the art that, for convenience and simplicity of description, the specific working processes of the above-described systems, apparatuses and units may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again.

In the several embodiments provided in the present application, it should be understood that the disclosed system, apparatus and method may be implemented in other ways. For example, the above-described apparatus embodiments are merely illustrative, and for example, the division of the units is only one logical division, and other divisions may be realized in practice, for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or units, and may be in an electrical, mechanical or other form.

The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.

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

The functions, if implemented in the form of software functional units and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present application or portions thereof that substantially contribute to the prior art may be embodied in the form of a software product stored in a storage medium and including instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present application. And the aforementioned storage medium includes: u disk, removable hard disk, read only memory, random access memory, magnetic or optical disk, etc. for storing program codes.

Claims

1. A method of transmitting data, comprising:

a source sending device sends a first data packet to a receiving device, wherein the first data packet comprises an original data packet and/or a first redundant packet, or the first data packet comprises a system packet and/or a first redundant packet, the first redundant packet is obtained by network coding of the original data packet, the original data packet is obtained according to original data, the system packet is obtained according to the original data packet, and the original data is a Service Data Unit (SDU) of a first protocol layer to be processed by a network coding function;

the source sending equipment receives first information from the receiving equipment;

the source sending equipment sends a second data packet to target sending equipment of the receiving equipment according to the first information, wherein the second data packet is used for recovering the original data by the receiving equipment;

wherein the first information is used to indicate at least one of:

the receiving device recovers a first SDU in SDUs of a second protocol layer according to the first data packet, wherein the second protocol layer and the first protocol layer are the same protocol layer or different protocol layers, the SDU of the second protocol layer corresponds to the SDU of the first protocol layer, or,

the number information of the redundant packets to be received, wherein the redundant packets to be received are used for recovering the original data by the receiving equipment; or,

information on the number of the first packets correctly received by the receiving device, or,

information on the number of the first data packets that the receiving device did not correctly receive.

2. The method of claim 1, wherein the target sending device is a device that communicates with the receiving device after the receiving device performs handover, and the source sending device is a device that communicates with the receiving device before the receiving device performs handover.

3. The method according to claim 1 or 2, wherein the second data packet comprises a second redundancy packet corresponding to the original data, and the second redundancy packet comprises the first redundancy packet and/or a redundancy packet different from the first redundancy packet.

4. The method of claim 3, further comprising:

and the source sending equipment sends first indication information to the target sending equipment, wherein the first indication information is used for indicating that the type of the second data packet is a redundant packet type.

5. The method of claim 4, wherein the second data packet is carried in a general packet radio service tunneling protocol (GTP) tunnel, and the first indication information is carried in a GTP header field of the GTP tunnel.

6. The method of claim 1 or 2, wherein the second data comprises a second SDU, of the SDUs of the second protocol layer, which does not include the first SDU.

7. The method of claim 6, further comprising:

the source sending equipment sends second indication information to the target sending equipment;

wherein the second indication information is used for indicating whether the target sending device executes the processing of the network coding function on the second data packet; and/or the presence of a gas in the gas,

the second indication information is used for indicating that the type of the second data packet is the SDU type.

8. The method of claim 6 or 7, further comprising:

the source sending device sends third indication information to a target sending device, where the third indication information is used to indicate the target sending device to execute information of a first coding block processed by a network coding function, or the third indication information is used to indicate the source sending device to execute information of a last coding block processed by the network coding function.

9. The method of claim 1 or 2, wherein the second data packet comprises a set of SDUs of the second protocol layer to which the original data corresponds.

10. The method of claim 9, further comprising:

the source sending device sends fourth indication information to the receiving device, where the fourth indication information is used to instruct the receiving device to delete data that is duplicated with all or part of data in the SDU of the second protocol layer, and the duplicated data includes at least one of: the PDU of the second protocol layer, the system package and/or the redundant package corresponding to the PDU of the second protocol layer, or the SDU of the second protocol layer successfully recovered through the system package and/or the redundant package corresponding to the PDU of the second protocol layer.

11. The method of claim 9 or 10, wherein the first protocol layer and the second protocol layer are the same protocol layer, and the SDU of the second protocol layer corresponding to the first packet includes a first sequence number;

and a set of each of the SDUs of the second protocol layer include a first sequence number, the first sequence number being used to identify the SDUs of the second protocol layer.

12. The method of any one of claims 1-11, further comprising:

the source sending device receives sixth indication information from the target sending device, where the sixth indication information is used to indicate whether the target sending device supports the processing of the network coding function.

13. The method of claim 12, further comprising:

the source sending device sends configuration information of the network coding function to the target sending device, wherein the configuration information comprises at least one of the following items:

network coding type, coding block size, system packet number, redundant packet number, coding coefficient selection, or convolution depth.

14. The method of any one of claims 1-13, wherein the first protocol layer comprises a service data adaptation protocol, SDAP, radio link control, RLC, or packet data convergence protocol, PDCP, layer, and the second protocol layer comprises a PDCP layer.

15. A data receiving method, comprising:

receiving, by a receiving device, a first data packet from a source sending device, where the first data packet includes an original data packet and/or a first redundant packet, or the first data packet includes a system packet and/or a first redundant packet, where the first redundant packet is obtained by network coding of the original data packet, the original data packet is obtained according to original data, the system packet is obtained according to the original data packet, and the original data is a service data unit SDU of a first protocol layer to be processed by a network coding function;

the receiving device sends first information to the source sending device, the first information is used for determining a second data packet from the source sending device to a target sending device, the second data packet is used for the receiving device to recover the original data, and the first information is used for indicating at least one of the following:

the number information of the first data packets which are not correctly received by the receiving equipment;

the receiving device receives a third data packet from the target transmitting device, wherein the third data packet corresponds to the second data packet.

16. The method of claim 15, wherein the target sending device is a device that communicates with the receiving device after the receiving device performs handover, and the source sending device is a device that communicates with the receiving device before the receiving device performs handover.

17. The method according to claim 15 or 16, wherein the second data packet comprises a second redundant packet corresponding to the original data, the second redundant packet comprises the first redundant packet and/or a redundant packet different from the first redundant packet; or,

the second data packet includes a second SDU of the SDUs of the second protocol layer, the second SDU not including the first SDU; or,

the second data packet includes a set of SDUs of the second protocol layer corresponding to the original data.

18. The method of claim 17, wherein the second data packet comprises a second redundant packet corresponding to the original data, the first protocol layer is higher than the second protocol layer, the third data packet corresponds to a PDU of the second protocol layer, and the PDU of the second protocol layer carries fifth indication information indicating whether the PDU is processed by a network coding function.

19. The method of claim 17, wherein the second data packet comprises the second SDU, and a third data packet corresponding to the second SDU comprises a PDU of the second protocol layer, the PDU carrying fifth indication information indicating whether the PDU is processed by a network coding function.

20. The method of claim 17, wherein the second data packet comprises SDUs for the set of the second protocol layers, further comprising:

the receiving device receives fourth indication information from the source transmitting device or the target transmitting device, where the fourth indication information is used to instruct the receiving device to delete data that is duplicated with all or part of data in the SDUs of the second protocol layer, and the duplicated data includes at least one of: the PDU of the second protocol layer, the system and/or the redundant packet corresponding to the PDU of the second protocol layer, or the SDU of the second protocol layer successfully recovered through the system and/or the redundant packet corresponding to the PDU of the second protocol layer.

21. The method of claim 17, wherein the second data packet comprises the set of SDUs of the second protocol layer, the first protocol layer and the second protocol layer are the same protocol layer, and the SDUs of the second protocol layer corresponding to the first data packet and the third data packet each comprise a first sequence number;

and each of the SDUs of the second protocol layer comprises a first sequence number, and the first sequence number is used for identifying the SDU of the second protocol layer.

22. The method of any one of claims 15-21, wherein the first protocol layer comprises a SDAP layer, a RLC layer, or a PDCP layer, and wherein the second protocol layer comprises a PDCP layer.

23. A data transmission method, comprising:

receiving, by a target sending device, a second data packet from a source sending device, where the second data packet is used by a receiving device to recover original data, and the original data is used for determining a first data packet sent by the source sending device to the receiving device, where the first data packet includes an original data packet and/or a first redundant packet, or the first data packet includes a system packet and/or a first redundant packet, where the first redundant packet is obtained by network coding the original data packet, the original data packet is obtained according to original data, the system packet is obtained according to the original data packet, and the original data is a service data unit SDU of a first protocol layer to be processed by a network coding function;

the target sending device sends a third data packet to the receiving device, wherein the third data packet corresponds to the second data packet;

wherein the second data packet relates to first information indicating at least one of:

the receiving device recovers a first SDU in SDUs of a second protocol layer according to the first data packet, wherein the second protocol layer and the first protocol layer are the same protocol layer or different protocol layers, and the SDU of the second protocol layer corresponds to the SDU of the first protocol layer, or,

24. A computer-readable storage medium having computer-readable instructions stored thereon which, when executed, perform the method of any of claims 1-23.

25. A computer program product having stored therein computer readable instructions which, when executed, perform the method of any one of claims 1 to 23.

26. An apparatus comprising circuitry to perform the method of any of claims 1-23.

27. An apparatus comprising a processor coupled with a memory, the memory storing instructions that, when executed, cause the apparatus to perform the method of any of claims 1-23.

28. An apparatus comprising means for performing the method of any one of claims 1-23.