Data transmission method and device

Abstract

A data transmission method and apparatus are provided, which relate to the field of communication technologies, and can reduce signaling overhead for reporting a status report and save resources during MBS data transmission. The method includes a distributed unit DU receiving a first Packet Data Convergence Protocol (PDCP) Packet Data Unit (PDU) from a central unit CU, where the first PDCP PDU carries data of a Multicast Broadcast Service (MBS). The DU transmits the first PDCP PDU to at least two terminal devices. The DU transmits a status report to the CU, where the status report indicates a result of the transmission of the first PDCP PDU to the at least two terminal devices.

Description

[Technical Field]

[0001] The present application relates to the field of communication technology, and in particular to data transmission methods and devices. [Background technology]

[0002] Multicast broadband service (MBS) is a service directed to multiple user equipments (UEs), such as live broadcast or scheduled program playback. There are two transmission modes for MBS data to be transmitted from the access network device to the terminal device. The first transmission mode is the point-to-multipoint (PTM) transmission mode, and the second transmission mode is the point-to-point (PTP) transmission mode.

[0003] The 5th Generation mobile communication technology (5G) system introduces a central unit (CU)-distributed unit (DU) split base station architecture. When packet data convergence protocol (PDCP) protocol data units (PDUs) are transmitted in the CU-DU architecture, the DU reports downlink data delivery status (DDDS) to the CU to communicate the transmission results of the PDCP PDUs to the DU, so that the CU can perform data flow control. However, the existing DDDS reporting solution has a large signaling overhead for MBS, causing resource waste. Summary of the Invention

[0004] The embodiments of the present application provide a data transmission method and apparatus, so as to reduce signaling overhead for reporting status reports and save resources during MBS data transmission.

[0005] According to a first aspect, a data transmission method is provided, the method including: a distributed unit (DU) receiving a first Packet Data Convergence Protocol (PDCP) Packet Data Unit (PDU) from a central unit (CU), the first PDCP PDU carrying data for a Multicast Broadcast Service (MBS); the DU transmitting the first PDCP PDU to at least two terminal devices; and the DU transmitting a status report to the CU, the status report indicating a result of the DU's transmission of the first PDCP PDU to the at least two terminal devices.

[0006] Based on the above technical solution, when a DU receives a first PDCP PDU from a CU, and the first PDCP PDU carries data of an MBS, the DU transmits the first PDCP PDU to at least two terminal devices and transmits a status report to the CU, where the status report indicates the result of transmitting the first PDCP PDU to the at least two terminal devices. Thus, when data of the MBS is transmitted, the signaling overhead for reporting the status report is reduced and resources are saved.

[0007] In one possible design, the status report indicates the result of the transmission of the first PDCP PDU to each of the at least two terminal devices. Based on this design, the terminal devices share the status report, thereby reducing signaling overhead.

[0008] In a possible design, the DU transmitting the first PDCP PDU to the at least two terminal devices includes: the DU transmitting the first PDCP PDU to the at least two terminal devices by using a radio link control (RLC) unacknowledged mode (UM).

[0009] In a possible design, the DU transmitting the first PDCP PDU to the at least two terminal devices includes: the DU transmitting the first PDCP PDU to the at least two terminal devices in a point-to-multipoint PTM mode.

[0010] In a possible design, the DU transmitting the first PDCP PDU to the at least two terminal devices includes: the DU transmitting the first PDCP PDU to a first terminal device of the at least two terminal devices by using RLC acknowledged mode AM, where the first terminal device includes at least one terminal device; the DU transmitting the first PDCP PDU to a second terminal device of the at least two terminal devices by using RLC UM, where the second terminal device includes at least one terminal device; and the status report indicating a result of the transmission of the first PDCP PDU to the first terminal device and a result of the transmission of the first PDCP PDU to the second terminal device. Based on this design, the results for the terminal devices are included in the status report, thereby reducing signaling overhead.

[0011] In a possible design, the DU transmitting the first PDCP PDU to the at least two terminal devices includes: the DU transmitting the first PDCP PDU in a PTM mode to a first terminal device of the at least two terminal devices, the first terminal device including at least one terminal device; the DU transmitting the first PDCP PDU in a PTP mode to a second terminal device of the at least two terminal devices, the second terminal device including at least one terminal device; and the status report indicating a result of the transmission of the first PDCP PDU to the first terminal device and a result of the transmission of the first PDCP PDU to the second terminal device. Based on this design, the results for the terminal devices are included in the status report, thereby reducing signaling overhead.

[0012] In a possible design, the DU transmitting the first PDCP PDU to the at least two terminal devices includes: the DU transmitting the first PDCP PDU in a PTM mode to a first terminal device of the at least two terminal devices, the first terminal device including at least one terminal device; the DU transmitting the first PDCP PDU in a PTP mode to a second terminal device of the at least two terminal devices, the second terminal device including at least one terminal device; and the status report indicating only a result of the transmission of the first PDCP PDU to the first terminal device. Based on this design, the result for the first terminal device is included in the status report, thereby reducing signaling overhead.

[0013] In a possible design, the DU sending the status report to the CU includes: the DU sending a first status report to the CU, where the first status report indicates a result of the transmission of the first PDCP PDU to the first terminal device; and the DU sending a second status report to the CU, where the second status report indicates a result of the transmission of the first PDCP PDU to the second terminal device. That is, the status report may be implemented based on two status reports. Based on this design, the first status report and the second status report may be sent separately, and the DU may send the status report without knowing the results of different transmission modes for all terminal devices, thereby improving the transmission efficiency of the status report.

[0014] In a possible design, the first status report carries first indication information, indicating that the first status report corresponds to the PTM mode. The second status report carries second indication information, indicating that the second status report corresponds to the PTP mode. Based on this design, the CU can determine, based on the first indication information, that the first status report is a combination of status reports of multiple terminal devices whose DUs transmit the first PDCP PDU in the PTM mode, and can determine, based on the second indication information, that the second status report is a combination of status reports of multiple terminal devices whose DUs transmit the first PDCP PDU in the PTP mode. When the CU determines the mode used by the DU to transmit the first PDCP PDU to at least two terminal devices, the CU can determine, based only on the first indication information and / or the second indication information, whether the received status report is complete, specifically, whether the status report is a combination of status reports of all terminal devices whose DUs transmit the first PDCP PDU, and whether the CU needs to wait for another status report.

[0015] In a possible design, the first status report carries ninth indication information, which indicates that the first status report corresponds to RLC AM. The second status report carries tenth indication information, which indicates that the second status report corresponds to RLC U. To MIt indicates that the ninth and tenth indications correspond to each other. Based on this design, the CU may determine, based on the ninth indication information, that the first status report is a combination of status reports of multiple terminal devices to which the DU transmits the first PDCP PDU by using RLC AM, and may determine, based on the tenth indication information, that the second status report is a combination of status reports of multiple terminal devices to which the DU transmits the first PDCP PDU by using RLC UM. When the CU determines the mode used by the DU to transmit the first PDCP PDU to at least two terminal devices, the CU may determine, based only on the ninth and / or tenth indication information, whether the received status report is complete, specifically, whether the status report is a combination of status reports of all terminal devices to which the DU transmits the first PDCP PDU, and whether the CU needs to wait for another status report.

[0016] In a possible design, the DU sending the first status report to the CU includes: the DU sending a sixth status report to the CU, the sixth status report indicating a result of in-order delivery of the first PDCP PDU to at least one of the first terminal devices; and the DU sending a seventh status report to the CU, the seventh status report indicating a result of out-of-order delivery of the first PDCP PDU to at least one of the first terminal devices. That is, the first status report may be implemented based on two status reports, thereby improving the efficiency of sending the status report.

[0017] In a possible design, the sixth status report carries eleventh indication information indicating that the sixth status report is a combination of status reports of terminal devices using ordered RLC AM among the first terminal devices, and the seventh status report carries twelfth indication information indicating that the seventh status report is a combination of status reports of terminal devices using unordered RLC AM among the first terminal devices.

[0018] In a possible design, the sixth status report carries thirteenth indication information indicating whether the sixth status report includes status reports of all of the first terminal devices, and / or the seventh status report carries thirteenth indication information indicating whether the seventh status report includes status reports of all of the first terminal devices. Based on this design, the CU may determine, based on the thirteenth indication information, whether the received sixth and / or seventh status report is complete, in other words, whether the sixth and / or seventh status report is a combination of status reports of all of the first terminal devices.

[0019] In a possible design, the first status report carries third indication information indicating whether the first status report includes status reports of all terminal devices included in the at least two terminal devices, and / or the second status report carries third indication information indicating whether the second status report includes status reports of all terminal devices included in the at least two terminal devices. Based on this design, when the DU, or the CU and the DU together, determines the mode used by the DU to transmit the first PDCP PDU to the at least two terminal devices, the CU may determine, based on the third indication information, whether the first status report and / or the second status report are complete, in other words, whether the first status report and / or the second status report are a combination of status reports of all terminal devices to which the DU transmits the first PDCP PDU.

[0020] In a possible design, the status report carries fourth indication information, and the fourth indication information indicates that the status report corresponds to RLC UM.

[0021] In a possible design, the status report carries first indication information, and the first indication information indicates that the status report corresponds to the PTM mode.

[0022] In a possible design, the status report carries fifth indication information, the fifth indication information indicating a desired buffer size for a radio bearer RB associated with the MBS, the first status report carries fifth indication information, the fifth indication information indicating a desired buffer size for a RB associated with the MBS, and / or the second status report carries fifth indication information, the fifth indication information indicating a desired buffer size for a RB associated with the MBS. Based on this design, the CU may determine a desired buffer size for a RB associated with the MBS based on the fifth indication information.

[0023] In a possible design, the status report carries sixth indication information, the sixth indication information indicating the desired data rate, the first status report carries sixth indication information, the sixth indication information indicating the desired data rate, and / or the second status report carries sixth indication information, the sixth indication information indicating the desired data rate. Based on this design, the CU may determine the desired data rate based on the sixth indication information.

[0024] In a possible design, the first PDCP PDU includes one or more PDCP PDUs, the status report carries seventh indication information, the seventh indication information indicating a highest sequence number (SN) of at least one PDCP PDU among the first PDCP PDUs that the DU has successfully transmitted, and / or the first status report carries seventh indication information, the seventh indication information indicating a highest sequence number (SN) of at least one PDCP PDU among the first PDCP PDUs that the DU has successfully transmitted, and / or the second status report carries seventh indication information, the seventh indication information indicating a highest sequence number (SN) of at least one PDCP PDU among the first PDCP PDUs that the DU has successfully transmitted. Based on this design, the CU may determine the highest sequence number (SN) of the at least one PDCP PDU among the first PDCP PDUs that the DU has successfully transmitted based on the seventh indication information.

[0025] In a possible design, the first PDCP PDU includes one or more PDCP PDUs, and the status report carries eighth indication information, and / or the first status report carries eighth indication information, and / or the second status report carries eighth indication information, wherein the eighth indication information indicates the number and starting SN of at least one PDCP PDU that has been successfully transmitted by a DU among the first PDCP PDUs, or the eighth indication information indicates the number and ending SN of at least one PDCP PDU that has been successfully transmitted by a DU among the first PDCP PDUs, or the eighth indication information indicates the starting SN and ending SN of at least one PDCP PDU that has been successfully transmitted by a DU among the first PDCP PDUs, or the eighth indication information indicates the number, starting SN, and ending SN of at least one PDCP PDU that has been successfully transmitted by a DU among the first PDCP PDUs.

[0026] In a possible design, the status report carries a bitmap indicating a result of the transmission of the first PDCP PDU to the at least two terminal devices, the first status report carries a bitmap indicating a result of the transmission of the first PDCP PDU to the first terminal device, and / or the second status report carries a bitmap indicating a result of the transmission of the first PDCP PDU to the second terminal device. Based on this design, the CU may determine the highest SN of at least one successfully transmitted PDCP PDU among the first PDCP PDUs based on the bitmap. MBS For PDCP PDUs carried in a CU, different PDCP PDUs may correspond to the PTP mode and the PTM mode separately. Therefore, feeding back the PDCP PDU transmission status based on the bitmap can avoid the following problem: when the highest SN indicated in the status report corresponding to the PTP mode and the highest SN indicated in the status report corresponding to the PTM mode are not the same, the CU cannot determine which highest SN should be used and it is difficult to decide.

[0027] In a possible design, the method further includes: the DU transmitting a third status report to the CU, the third status report being a status report dedicated to feeding back a desired buffer size of RBs associated with the MBS; the DU transmitting a fourth status report to the CU, the fourth status report being a status report dedicated to feeding back a desired data rate; and / or the DU transmitting a fifth status report to the CU, the fifth status report being a status report dedicated to feeding back a desired buffer size and a desired data rate of RBs associated with the MBS. Based on this design, for relevant information unrelated to the terminal device, the DU may feedback the information by using a status report dedicated to feedback of the information. Based on this design, the CU may determine the status report of the desired buffer size of RBs associated with the MBS based on the third status report and may also determine the desired data rate based on the fourth status report, or may determine the desired buffer size and the desired data rate of RBs associated with the MBS based on the fifth status report.

[0028] In a possible design, the DU sending the status report to the CU includes the DU sending the status report to the CU over a first channel, where the first channel is a General Packet Radio Service Tunneling Protocol (GTP-User Plane) U tunnel shared by multiple terminal devices. Alternatively, the DU sending the status report to the CU over a second channel, where the second channel is a GTP-U tunnel dedicated to a single terminal device. Based on this design, the DU may select an appropriate status report assembly method and an appropriate status report reporting method based on the GTP-U tunnel establishment status.

[0029] According to a second aspect, a data transmission method is provided, including a CU transmitting a first PDCP PDU to a DU, the first PDCP PDU carrying data of an MBS, and the CU receiving a status report from the DU, the status report indicating a result of transmitting the first PDCP PDU to at least two terminal devices.

[0030] In a possible design, the status report indicates the result of the transmission of the first PDCP PDU to each of the at least two end devices.

[0031] In one possible design, the CU receiving the status report from the DU includes the CU receiving a first status report from the DU, the first status report indicating a result of transmitting the first PDCP PDU to a first terminal device of the at least two terminal devices, the first terminal device including the at least one terminal device, and the CU receiving a second status report from the DU, the second status report indicating a result of transmitting the first PDCP PDU to a second terminal device of the at least two terminal devices, the second terminal device including the at least one terminal device.

[0032] In one possible design, the first status report carries first indication information, the first indication information indicating that the first status report corresponds to the PTM mode, and the second status report carries second indication information, the second indication information indicating that the second status report corresponds to the PTP mode.

[0033] In a possible design, the first status report carries ninth indication information, which indicates that the first status report corresponds to RLC AM. The second status report carries tenth indication information, which indicates that the second status report corresponds to RLC U. To M Indicates that it corresponds.

[0034] In a possible design, CU First status report Received from DU To do this: CU Sixth Status Report Received from DU and a sixth status report indicating a result of sequentially delivering the first PDCP PDU to at least one of the first terminal devices. CU The 7th status report Received from DU and the seventh status report indicates the result of out-of-order delivery of the first PDCP PDU to at least one of the first end devices.

[0035] In a possible design, the sixth status report carries eleventh indication information indicating that the sixth status report is a combination of status reports of terminal devices using ordered RLC AM among the first terminal devices, and the seventh status report carries twelfth indication information indicating that the seventh status report is a combination of status reports of terminal devices using unordered RLC AM among the first terminal devices.

[0036] In a possible design, the sixth status report carries thirteenth indication information, which indicates whether the sixth status report includes status reports of all terminal devices among the first terminal devices, and / or the seventh status report carries thirteenth indication information, which indicates whether the seventh status report includes status reports of all terminal devices among the first terminal devices.

[0037] In a possible design, the first status report carries third indication information, the third indication information indicating whether the first status report includes status reports of all terminal devices included in the at least two terminal devices, and / or the second status report carries third indication information, the third indication information indicating whether the second status report includes status reports of all terminal devices included in the at least two terminal devices.

[0038] In a possible design, the status report carries fourth indication information, and the fourth indication information indicates that the status report corresponds to RLC UM.

[0039] In a possible design, the status report carries first indication information, and the first indication information indicates that the status report corresponds to the PTM mode.

[0040] In a possible design, the status report carries fifth indication information, the fifth indication information indicating a desired buffer size of the RB associated with the MBS, the first status report carries fifth indication information, the fifth indication information indicating a desired buffer size of the RB associated with the MBS, and / or the second status report carries fifth indication information, the fifth indication information indicating a desired buffer size of the RB associated with the MBS.

[0041] In a possible design, the status report carries sixth indication information, the sixth indication information indicating the desired data rate, the first status report carries sixth indication information, the sixth indication information indicating the desired data rate, and / or the second status report carries sixth indication information, the sixth indication information indicating the desired data rate.

[0042] In a possible design, the first PDCP PDU includes one or more PDCP PDUs, the status report carries seventh indication information, the seventh indication information indicating the highest SN of at least one PDCP PDU among the first PDCP PDUs that the DU has successfully transmitted, the first status report carries seventh indication information, the seventh indication information indicating the highest SN of at least one PDCP PDU among the first PDCP PDUs that the DU has successfully transmitted, and / or the second status report carries seventh indication information, the seventh indication information indicating the highest SN of at least one PDCP PDU among the first PDCP PDUs that the DU has successfully transmitted.

[0043] In a possible design, the first PDCP PDU includes one or more PDCP PDUs, and the status report carries eighth indication information, and / or the first status report carries eighth indication information, and / or the second status report carries eighth indication information, wherein the eighth indication information indicates the number and starting SN of at least one PDCP PDU that has been successfully transmitted by a DU among the first PDCP PDUs, or the eighth indication information indicates the number and ending SN of at least one PDCP PDU that has been successfully transmitted by a DU among the first PDCP PDUs, or the eighth indication information indicates the starting SN and ending SN of at least one PDCP PDU that has been successfully transmitted by a DU among the first PDCP PDUs, or the eighth indication information indicates the number, starting SN, and ending SN of at least one PDCP PDU that has been successfully transmitted by a DU among the first PDCP PDUs.

[0044] In a possible design, the status report carries a bitmap indicating a result of transmitting the first PDCP PDU to at least two terminal devices, the first status report carries a bitmap indicating a result of transmitting the first PDCP PDU to the first terminal device, and / or the second status report carries a bitmap indicating a result of transmitting the first PDCP PDU to the second terminal device.

[0045] In a possible design, the method further includes: the CU receiving from the DU a third status report, the third status report being a status report dedicated to feeding back a desired buffer size of an RB associated with the MBS; the CU receiving from the DU a fourth status report, the fourth status report being a status report dedicated to feeding back a desired data rate; and / or the CU receiving from the DU a fifth status report, the fifth status report being a status report dedicated to feeding back a desired buffer size and a desired data rate of an RB associated with the MBS.

[0046] In one possible design, the CU receiving the status report from the DU includes the CU receiving the status report from the DU via a first channel, the first channel being a General Packet Radio Service Tunneling Protocol (GTP-User Plane) U-tunnel shared by multiple terminal devices. Alternatively, the CU receiving the status report from the DU via a second channel, the second channel being a GTP-U-tunnel dedicated to a single terminal device.

[0047] In a possible design, the method further includes: the CU determining a desired buffer size for RBs associated with the MBS based on the fifth indication information carried in the status report and / or determining a desired data rate based on the sixth indication information carried in the status report. Alternatively, the CU determines a desired buffer size for RBs associated with the MBS based on the fifth indication information carried in the first status report or the fifth indication information carried in the second status report, and / or the CU determines a desired data rate based on the sixth indication information carried in the first status report or the sixth indication information carried in the second status report. Alternatively, the CU determines a desired buffer size for RBs associated with the MBS based on the third status report and / or determines a desired data rate based on the fourth status report. Alternatively, the CU determines a desired buffer size and / or a desired data rate for RBs associated with the MBS based on the fifth status report.

[0048] In a possible design, the method further includes: the CU determining, based on seventh indication information carried in the status report, the first status report, or the second status report, a highest SN of at least one successfully transmitted PDCP PDU among the first PDCP PDUs. Alternatively, the CU determining, based on eighth indication information carried in the status report, the first status report, or the second status report, a highest SN of at least one successfully transmitted PDCP PDU among the first PDCP PDUs. Alternatively, the CU determining, based on a bitmap carried in the status report, the first status report, or the second status report, a highest SN of at least one successfully transmitted PDCP PDU among the first PDCP PDUs.

[0049] According to a third aspect, a communication apparatus is provided, including a communication module configured to receive a first PDCP PDU from a CU, the first PDCP PDU carrying data of an MBS. The communication module is further configured to transmit the first PDCP PDU to at least two terminal devices. The communication module is further configured to transmit a status report to the CU, the status report indicating a result of transmitting the first PDCP PDU to the at least two terminal devices.

[0050] In a possible design, the status report indicates the result of the transmission of the first PDCP PDU to each of the at least two end devices.

[0051] In a possible design, the communication module is further configured to transmit the first PDCP PDU to the at least two terminal devices by using RLC UM.

[0052] In a possible design, the communication module is further configured to transmit the first PDCP PDU to the at least two terminal devices in the PTM mode.

[0053] In one possible design, the communication module is further configured to transmit the first PDCP PDU to a first terminal device of the at least two terminal devices, the first terminal device including at least one terminal device, by using RLC acknowledge AM and to transmit the first PDCP PDU to a second terminal device of the at least two terminal devices, the second terminal device including at least one terminal device, by using RLC UM. The status report indicates a result of transmitting the first PDCP PDU to the first terminal device and a result of transmitting the first PDCP PDU to the second terminal device.

[0054] In a possible design, the communication module is further configured to transmit the first PDCP PDU in a PTM mode to a first terminal of the at least two terminal devices, the first terminal device including at least one terminal device, and to transmit the first PDCP PDU in a PTP mode to a second terminal device of the at least two terminal devices, the second terminal device including at least one terminal device, and the status report indicates a result of transmitting the first PDCP PDU to the first terminal device and a result of transmitting the first PDCP PDU to the second terminal device.

[0055] In a possible design, the communication module is further configured to transmit the first PDCP PDU in a PTM mode to a first terminal of the at least two terminal devices, the first terminal device including at least one terminal device, and to transmit the first PDCP PDU in a PTP mode to a second terminal device of the at least two terminal devices, the second terminal device including at least one terminal device, and the status report indicates only a result of the transmission of the first PDCP PDU to the first terminal device.

[0056] In a possible design, the communication module is further configured to send a first status report to the CU, the first status report indicating a result of the transmission of the first PDCP PDU to the first terminal device, and the communication module is further configured to send a second status report to the CU, the second status report indicating a result of the transmission of the first PDCP PDU to the second terminal device.

[0057] In one possible design, the first status report carries first indication information, the first indication information indicating that the first status report corresponds to the PTM mode, and the second status report carries second indication information, the second indication information indicating that the second status report corresponds to the PTP mode.

[0058] In a possible design, the first status report carries ninth indication information, which indicates that the first status report corresponds to RLC AM. The second status report carries tenth indication information, which indicates that the second status report corresponds to RLC U. To M Indicates that it corresponds.

[0059] In a possible design, the communication module is further configured to send a sixth status report to the CU, the sixth status report indicating a result of in-order delivery of the first PDCP PDU to at least one of the first terminal devices, and a seventh status report to the CU, the seventh status report indicating a result of out-of-order delivery of the first PDCP PDU to at least one of the first terminal devices.

[0060] In a possible design, the sixth status report carries eleventh indication information indicating that the sixth status report is a combination of status reports of terminal devices using ordered RLC AM among the first terminal devices, and the seventh status report carries twelfth indication information indicating that the seventh status report is a combination of status reports of terminal devices using unordered RLC AM among the first terminal devices.

[0061] In a possible design, the sixth status report carries thirteenth indication information, which indicates whether the sixth status report includes status reports of all terminal devices among the first terminal devices, and / or the seventh status report carries thirteenth indication information, which indicates whether the seventh status report includes status reports of all terminal devices among the first terminal devices.

[0062] In a possible design, the first status report carries third indication information, the third indication information indicating whether the first status report includes status reports of all terminal devices included in the at least two terminal devices, and / or the second status report carries third indication information, the third indication information indicating whether the second status report includes status reports of all terminal devices included in the at least two terminal devices.

[0063] In a possible design, the status report carries fourth indication information, and the fourth indication information indicates that the status report corresponds to RLC UM.

[0064] In a possible design, the status report carries first indication information, and the first indication information indicates that the status report corresponds to the PTM mode.

[0065] In a possible design, the status report carries fifth indication information, the fifth indication information indicating a desired buffer size of a radio bearer RB associated with the MBS, the first status report carries fifth indication information, the fifth indication information indicating a desired buffer size of an RB associated with the MBS, and / or the second status report carries fifth indication information, the fifth indication information indicating a desired buffer size of an RB associated with the MBS.

[0066] In a possible design, the status report carries sixth indication information, the sixth indication information indicating the desired data rate, the first status report carries sixth indication information, the sixth indication information indicating the desired data rate, and / or the second status report carries sixth indication information, the sixth indication information indicating the desired data rate.

[0067] In a possible design, the first PDCP PDU includes one or more PDCP PDUs, the status report carries seventh indication information, the seventh indication information indicating the highest sequence number SN of at least one PDCP PDU among the first PDCP PDUs that the DU has successfully transmitted, the first status report carries seventh indication information, the seventh indication information indicating the highest sequence number SN of at least one PDCP PDU among the first PDCP PDUs that the DU has successfully transmitted, and / or the second status report carries seventh indication information, the seventh indication information indicating the highest sequence number SN of at least one PDCP PDU among the first PDCP PDUs that the DU has successfully transmitted.

[0068] In a possible design, the first PDCP PDU includes one or more PDCP PDUs, and the status report carries eighth indication information, and / or the first status report carries eighth indication information, and / or the second status report carries eighth indication information, wherein the eighth indication information indicates the number and starting SN of at least one PDCP PDU that has been successfully transmitted by a DU among the first PDCP PDUs, or the eighth indication information indicates the number and ending SN of at least one PDCP PDU that has been successfully transmitted by a DU among the first PDCP PDUs, or the eighth indication information indicates the starting SN and ending SN of at least one PDCP PDU that has been successfully transmitted by a DU among the first PDCP PDUs, or the eighth indication information indicates the number, starting SN, and ending SN of at least one PDCP PDU that has been successfully transmitted by a DU among the first PDCP PDUs.

[0069] In a possible design, the status report carries a bitmap indicating a result of transmitting the first PDCP PDU to at least two terminal devices, the first status report carries a bitmap indicating a result of transmitting the first PDCP PDU to the first terminal device, and / or the second status report carries a bitmap indicating a result of transmitting the first PDCP PDU to the second terminal device.

[0070] In a possible design, the communication module is further configured to send a third status report to the CU, the third status report being a status report dedicated to feeding back a desired buffer size of an RB associated with the MBS; the communication module is further configured to send a fourth status report to the CU, the fourth status report being a status report dedicated to feeding back a desired data rate; and / or the communication module is further configured to send a fifth status report to the CU, the fifth status report being a status report dedicated to feeding back a desired buffer size and a desired data rate of an RB associated with the MBS.

[0071] In one possible design, the communication module is further configured to send the status report to the CU over a first channel, the first channel being a General Packet Radio Service Tunneling Protocol (GTP-User Plane U) tunnel shared by multiple terminal devices. Alternatively, the communication module is further configured to send the status report to the CU over a second channel, the second channel being a GTP-U tunnel dedicated to a single terminal device.

[0072] According to a fourth aspect, a communication apparatus is provided, including a communication module configured to transmit a first PDCP PDU to a DU, the first PDCP PDU carrying data of an MBS, and further configured to receive a status report from the DU, the status report indicating a result of transmitting the first PDCP PDU to at least two terminal devices.

[0073] In a possible design, the status report indicates the result of the transmission of the first PDCP PDU to each of the at least two end devices.

[0074] In a possible design, the communication module is further configured to receive a first status report from the DU, the first status report indicating a result of transmitting the first PDCP PDU to a first terminal device of the at least two terminal devices, the first terminal device including the at least one terminal device, and the communication module is further configured to receive a second status report from the DU, the second status report indicating a result of transmitting the first PDCP PDU to a second terminal device of the at least two terminal devices, the second terminal device including the at least one terminal device.

[0075] In one possible design, the first status report carries first indication information, the first indication information indicating that the first status report corresponds to the PTM mode, and the second status report carries second indication information, the second indication information indicating that the second status report corresponds to the PTP mode.

[0076] In a possible design, the first status report carries ninth indication information, which indicates that the first status report corresponds to RLC AM, and the second status report carries tenth indication information, which indicates that the second status report corresponds to RLC UM.

[0077] In a possible design, the communication module is further configured to receive a sixth status report from the DU, the sixth status report indicating a result of in-order delivery of the first PDCP PDU to at least one terminal device of the first terminal devices, and a seventh status report from the DU, the seventh status report indicating a result of out-of-order delivery of the first PDCP PDU to at least one terminal device of the first terminal devices.

[0078] In a possible design, the sixth status report carries eleventh indication information indicating that the sixth status report is a combination of status reports of terminal devices using ordered RLC AM among the first terminal devices, and the seventh status report carries twelfth indication information indicating that the seventh status report is a combination of status reports of terminal devices using unordered RLC AM among the first terminal devices.

[0079] In a possible design, the sixth status report carries thirteenth indication information, which indicates whether the sixth status report includes status reports of all terminal devices among the first terminal devices, and / or the seventh status report carries thirteenth indication information, which indicates whether the seventh status report includes status reports of all terminal devices among the first terminal devices.

[0080] In a possible design, the first status report carries third indication information, the third indication information indicating whether the first status report includes status reports of all terminal devices included in the at least two terminal devices, and / or the second status report carries third indication information, the third indication information indicating whether the second status report includes status reports of all terminal devices included in the at least two terminal devices.

[0081] In a possible design, the status report carries fourth indication information, and the fourth indication information indicates that the status report corresponds to RLC UM.

[0082] In a possible design, the status report carries first indication information, and the first indication information indicates that the status report corresponds to the PTM mode.

[0083] In a possible design, the status report carries fifth indication information, the fifth indication information indicating a desired buffer size of the RB associated with the MBS, the first status report carries fifth indication information, the fifth indication information indicating a desired buffer size of the RB associated with the MBS, and / or the second status report carries fifth indication information, the fifth indication information indicating a desired buffer size of the RB associated with the MBS.

[0084] In a possible design, the status report carries sixth indication information, the sixth indication information indicating the desired data rate, the first status report carries sixth indication information, the sixth indication information indicating the desired data rate, and / or the second status report carries sixth indication information, the sixth indication information indicating the desired data rate.

[0085] In a possible design, the first PDCP PDU includes one or more PDCP PDUs, the status report carries seventh indication information, the seventh indication information indicating the highest SN of at least one PDCP PDU among the first PDCP PDUs that the DU has successfully transmitted, the first status report carries seventh indication information, the seventh indication information indicating the highest SN of at least one PDCP PDU among the first PDCP PDUs that the DU has successfully transmitted, and / or the second status report carries seventh indication information, the seventh indication information indicating the highest SN of at least one PDCP PDU among the first PDCP PDUs that the DU has successfully transmitted.

[0086] In a possible design, the first PDCP PDU includes one or more PDCP PDUs, and the status report carries eighth indication information, and / or the first status report carries eighth indication information, and / or the second status report carries eighth indication information, wherein the eighth indication information indicates the number and starting SN of at least one PDCP PDU that has been successfully transmitted by a DU among the first PDCP PDUs, or the eighth indication information indicates the number and ending SN of at least one PDCP PDU that has been successfully transmitted by a DU among the first PDCP PDUs, or the eighth indication information indicates the starting SN and ending SN of at least one PDCP PDU that has been successfully transmitted by a DU among the first PDCP PDUs, or the eighth indication information indicates the number, starting SN, and ending SN of at least one PDCP PDU that has been successfully transmitted by a DU among the first PDCP PDUs.

[0087] In a possible design, the status report carries a bitmap indicating a result of transmitting the first PDCP PDU to at least two terminal devices, the first status report carries a bitmap indicating a result of transmitting the first PDCP PDU to the first terminal device, and / or the second status report carries a bitmap indicating a result of transmitting the first PDCP PDU to the second terminal device.

[0088] In a possible design, the communication module is further configured to receive a third status report from the DU, the third status report being a status report dedicated to feeding back a desired buffer size of an RB associated with the MBS; the communication module is further configured to receive a fourth status report from the DU, the fourth status report being a status report dedicated to feeding back a desired data rate; and / or the communication module is further configured to receive a fifth status report from the DU, the fifth status report being a status report dedicated to feeding back a desired buffer size and a desired data rate of an RB associated with the MBS.

[0089] In a possible design, the communication module is further configured to receive a status report from the DU via a first channel, the first channel being a General Packet Radio Service Tunneling Protocol (GTP-User Plane) U-tunnel shared by multiple terminal devices. Alternatively, the communication module is further configured to receive a status report from the DU via a second channel, the second channel being a GTP-U-tunnel dedicated to a single terminal device.

[0090] In a possible design, the apparatus further includes a processing module. The processing module is configured to determine a desired buffer size for RBs associated with the MBS based on the fifth indication information carried in the status report and / or determine a desired data rate based on the sixth indication information carried in the status report. Alternatively, the processing module is further configured to determine a desired buffer size for RBs associated with the MBS based on the fifth indication information carried in the first status report or the fifth indication information carried in the second status report and / or determine a desired data rate based on the sixth indication information carried in the first status report or the sixth indication information carried in the second status report. Alternatively, the processing module is further configured to determine a desired buffer size for RBs associated with the MBS based on the third status report and / or determine a desired data rate based on the fourth status report. Alternatively, the processing module is further configured to determine a desired buffer size and / or a desired data rate for RBs associated with the MBS based on the fifth status report.

[0091] In a possible design, the processing module is further configured to determine, based on seventh indication information carried in the status report, the first status report, or the second status report, the highest SN of at least one successfully transmitted PDCP PDU among the first PDCP PDUs. Alternatively, the processing module is further configured to determine, based on eighth indication information carried in the status report, the first status report, or the second status report, the highest SN of at least one successfully transmitted PDCP PDU among the first PDCP PDUs. Alternatively, the processing module is further configured to determine, based on a bitmap carried in the status report, the first status report, or the second status report, the highest SN of at least one successfully transmitted PDCP PDU among the first PDCP PDUs.

[0092] According to a fifth aspect, a communication device is provided, the communication device including a processor and a transceiver configured to implement the method provided in any one of the first aspect, the second aspect, or the design of the first aspect and the second aspect, the processor configured to perform the processing operations of the corresponding method, and the transceiver configured to perform the receiving / transmitting operations of the corresponding method.

[0093] According to a sixth aspect, a computer-readable storage medium is provided, the computer-readable storage medium storing computer instructions, which, when executed by a computer, can cause the computer to perform the method provided in any one of the first aspect, the second aspect, or the design of the first and second aspects.

[0094] According to a seventh aspect, there is provided a computer program product comprising computer instructions which, when executed on a computer, enable the computer to perform the method provided in any one of the first aspect, the second aspect, or the design of the first and second aspects.

[0095] According to an eighth aspect, a chip is provided, including a processor, which, when executing instructions, is configured to perform a method provided in any of the designs of the first and second aspects.

[0096] According to a ninth aspect, a chip is provided. The chip includes a processing circuit and a transceiver pin. The processing circuit and the transceiver pin are configured to implement the method provided in any one of the first aspect, the second aspect, and the design of the first and second aspects. The processing circuit is configured to perform the processing operations of the corresponding method, and the transceiver pin is configured to perform the receive / transmit operations of the corresponding method.

[0097] According to a tenth aspect, there is provided a communication system, comprising a communication device provided in accordance with the third aspect or any one of the designs of the third aspect, and a communication device provided in accordance with the fourth aspect or any one of the designs of the fourth aspect.

[0098] It should be noted that the technical effects obtained by the design of any of the second to tenth aspects should refer to the technical effects obtained by the corresponding design of the first aspect, and the details will not be described again here. [Brief explanation of the drawings]

[0099] [Figure 1] 1 is a schematic diagram of the architecture of a data transmission system according to an embodiment of the present application; [Figure 2] 1A is a schematic diagram of the architecture of a 4G base station according to an embodiment of the present application, and FIG. 1B is a schematic diagram of the architecture of a 5G base station according to an embodiment of the present application. [Figure 3] FIG. 2 is a schematic diagram of a CU-DU architecture divided based on protocol stacks, according to an embodiment of the present application. [Figure 4] 1 is a schematic diagram of a structure of a communication device according to an embodiment of the present application; [Figure 5] FIG. 10 is a schematic diagram of the structure of another communication device according to an embodiment of the present application. [Figure 6] 1 is a schematic diagram of an MBS transmission architecture according to an embodiment of the present application; [Figure 7] 1 is a schematic flowchart of a data transmission method according to an embodiment of the present application; [Figure 8] FIG. 2 is a schematic diagram of a bitmap of a PDCP PDU according to an embodiment of the present application. DETAILED DESCRIPTION OF THE INVENTION

[0100] The following describes the technical solutions in the embodiments of the present application with reference to the accompanying drawings in the embodiments of the present application.

[0101] In the description of this application, unless otherwise specified, " / " means "or." For example, A / B may represent A or B. The term "and / or" in this specification describes only an association relationship between related objects and indicates that three relationships may exist. For example, A and / or B may represent the following three relationships: only A exists, both A and B exist, and only B exists. Furthermore, "at least one" means one or more, and "multiple" means two or more. Terms such as "first" and "second" do not limit the quantity and execution order, and terms such as "first" and "second" do not indicate a clear distinction.

[0102] It should be noted that terms such as "example," "for example," and the like are used herein as examples, illustrations, or explanations. Any embodiment or design scheme described herein as an "example" or "for example" should not be described as preferred or having more advantages than other embodiments or design schemes. Indeed, the use of words such as "example," "for example," and the like is intended to concretely present the relevant concept.

[0103] In the description of this application, "indication" may include direct indication and indirect indication, or may include explicit indication and implicit indication. Information indicated by specific information is called referent information. In a specific implementation process, there are multiple ways to indicate referent information. For example, referent information may be directly indicated based on the referent information, an index of the referent information, etc. As another example, referent information may be indirectly indicated by indicating other information. There is an association relationship between the other information and the referent information. As another example, only a part of the referent information may be indicated, and the remaining part of the referent information is already known or pre-agreed upon. Furthermore, specific information may also be indicated by using a pre-agreed (e.g., specified in a protocol) arrangement sequence of various information to reduce indication overhead to some extent.

[0104] Furthermore, the network architectures and service scenarios described in the embodiments of the present application are intended to more clearly describe the technical solutions in the embodiments of the present application, and do not constitute limitations on the technical solutions provided in the embodiments of the present application. Those skilled in the art may recognize that with the advancement of network architectures and the emergence of new service scenarios, the technical solutions provided in the embodiments of the present application may also be applicable to similar technical problems.

[0105] 1 shows a data transmission system 100 according to an embodiment of the present application. The data transmission system includes a CU 101, a DU 102, and at least one terminal device. In this system architecture, the communication system is formed by a CU-DU split base station and multiple terminal devices. Optionally, one CU may be connected to multiple DUs (not shown). In the communication system, MBS data is transmitted from the CU to the DU, and then transmitted by the DU to multiple terminal devices.

[0106] Optionally, the CU and DU in this embodiment of the present application may communicate with each other directly, or may communicate with each other via transfer by other devices, which is not particularly limited in this embodiment of the present application.

[0107] 1 may be used in various communication systems, such as a new radio (NR) communication system using 5G communication technology, a future evolved system, or a system integrating multiple communications. The technical solutions provided herein may be applied to multiple application scenarios, such as machine-to-machine (M2M), macro-micro communication, enhanced mobile broadband (eMBB), ultra-reliable low-latency communication (uRLLC), massive machine-type communication (mMTC), E-UTRA new radio dual connectivity (EN-DC) networking, multicast broadcast single frequency network (MBSFN), and single frequency network (SFN) scenarios.

[0108] Optionally, the terminal device in this embodiment of the present application is a device equipped with a wireless transceiver function. The terminal device may be located on the ground, including indoors, outdoors, handheld, or vehicle-mounted, or may be located on the water surface (e.g., on a boat), or may be located in the air (e.g., on an airplane, balloon, or satellite). The terminal device may be user equipment (UE). The UE may be a handheld device, a vehicle, an in-vehicle device, a wearable device, or a computing device equipped with a wireless communication function. For example, the UE may be a mobile phone, a tablet computer, or a computer equipped with a wireless transceiver function. The terminal device may be a virtual reality (VR) terminal device, an augmented reality (AR) terminal device, a wireless terminal device in industrial control, a wireless terminal device in unmanned driving, a wireless terminal device in telemedicine, a wireless terminal device in a smart grid, a wireless terminal device in a smart city, a wireless terminal device in a smart home, etc. In this embodiment of the present application, an apparatus configured to implement the functions of a terminal device may be a terminal device, or may be an apparatus that can assist a terminal device to implement functions, such as a chip system. In this embodiment of the present application, the chip system may include a chip, or may include a chip and other discrete components. In this embodiment of the present application, an example in which an apparatus configured to implement the functions of a terminal device is a terminal device is used to describe the technical solution provided in this embodiment of the present application.

[0109] For example, Figure 2a is a schematic architecture diagram of a base station in the 4th Generation mobile communication technology (4G) system. A 4G base station is called an evolved NodeB (eNB). From the perspective of physical module structure, a 4G base station may include a baseband unit (BBU), a radio remote unit (RRU), and an antenna. Each 4G base station has a set of BBUs and is directly connected to the core network via the BBUs.

[0110] Figure 2b is a schematic architecture diagram of a base station in the 5th Generation mobile communication technology (5G) system. A 5G base station is called a gNodeB (gNB / ng-eNB) and may include a CU and a DU. In the 5G base station architecture, the RRU and antenna in a 4G base station are combined into an active antenna unit (AAU), and the BBU in a 4G base station is divided into a CU and a DU. The DU parts of different 5G base stations are deployed independently, and the CU parts of different 5G base stations are deployed centrally. Each 5G base station has a DU. Different 5G base stations share a CU to access the core network for centralized management.

[0111] It should be understood that the 4G base station and the 5G base station are specific examples, and both belong to the radio access network device and are configured to achieve the functions of the radio access network or the radio access device. Therefore, the base station can also be replaced by the radio access network.

[0112] Optionally, the CU and DU in the embodiments of the present application may be understood as divisions of radio access network devices from the perspective of logical functions. The CU and DU may be physically separated or co-located. This is not particularly limited in this embodiment of the present application. The CU and DU may be connected via an interface, for example, the interface may be an F1 interface. The CU and DU may be divided based on the protocol layer of the radio network. For example, as shown in FIG. 3, the functions of the radio resource control (RRC) layer, service data adaptation protocol (SDAP) layer, and PDCP layer may be set in the CU and used to implement functions such as data encryption / decryption, integrity protection, and sorting. The functions of the radio link control (RLC) layer, media access control (MAC) layer, physical layer (PHY), etc. may be set in the DU and used to implement functions such as feedback, scheduling, data packet segmentation, and concatenation. It should be understood that such division of the CU and DU processing functions based on protocol layers is merely an example, and the division may be performed in other ways, which is not particularly limited in this embodiment of the present application.

[0113] The CU and DU are connected via an F1 interface. The CU corresponds to a gNB and is connected to a core network via an NG interface; the CU corresponds to a gNB and is connected to another gNB via an Xn interface; and the CU may also correspond to a gNB and is connected to another eNB via an X2 interface to perform dual connectivity operations. It should be understood that all of the above interfaces are logical interfaces. In 5G networks and other future networks, the above interfaces may have other names, which is not a limitation in this embodiment of the present application.

[0114] For example, referring to Figure 3, a procedure for transmitting MBS data based on a radio access network protocol stack is described. The MBS data first arrives at the PDCP layer of the CU. After being processed by the PDCP layer of the CU, the MBS data is delivered to the RLC layer of the DU. The RLC layer of the DU then delivers the MBS data to the MAC layer and the physical layer, and finally, the MBS data is transmitted to the terminal device via the antenna over the air interface. Correspondingly, each protocol layer of the terminal device performs corresponding processing on the data packets in the reverse order to that on the base station side to receive the MBS data.

[0115] It should be understood that MBS data needs to be processed at each layer when it is present at each layer, and each layer has a corresponding functional entity for performing a corresponding function, for example, a PDCP entity at the PDCP layer or an RLC entity at the RLC layer.

[0116] 1 in this embodiment of the present application may be implemented by one device, or may be implemented together by multiple devices, or may be a functional module within a device. This is not particularly limited in this embodiment of the present application. It should be understood that the above functions may be network elements within a hardware device, or may be software functions executed on dedicated hardware, or may be virtual modules instantiated on a platform (e.g., a cloud platform).

[0117] For example, the CU or DU in Fig. 1 in this embodiment of the present application may be implemented by the communication device in Fig. 4. Fig. 4 is a schematic diagram of a hardware structure of a communication device according to an embodiment of the present application. The communication device 400 includes a processor 401, a communication line 402, a memory 403, and at least one communication interface (in Fig. 4, the fact that the communication device 400 includes the communication interface 404 is merely used as an example for explanation).

[0118] The processor 401 may be a general-purpose central processing unit (CPU), a microprocessor, an application-specific integrated circuit (ASIC), or one or more integrated circuits configured to control program execution of the solutions of the present application.

[0119] The communication lines 402 may include channels that transmit information between the above components.

[0120] The communication interface 404 may be referred to as a transceiver or any transceiver-based device and is configured to communicate with other devices or communication networks, such as Ethernet, a radio access network (RAN), or a wireless local area network (WLAN).

[0121] Memory 403 may be read-only memory (ROM) or other type of static storage device capable of storing static information and instructions, or random access memory (RAM) or other type of dynamic storage device capable of storing information and instructions. Alternatively, memory 403 may be electrically erasable programmable read-only memory (EEPROM), compact disc read-only memory (CD-ROM) or other compact disc storage, optical disc storage (including compact optical discs, laser discs, optical discs, digital versatile discs, Blu-ray discs, etc.), magnetic disc storage media or other magnetic storage devices, or any other medium usable to carry expected program code in the form of instructions or data structures and accessible by a computer. However, memory 403 is not limited to these. The memory may exist independently and be connected to the processor via communication lines 402. Alternatively, the memory may be integrated with the processor.

[0122] The memory 403 is configured to store computer instructions for implementing the solutions of the present application, and the processor 401 controls the execution. The processor 401 is configured to execute the computer instructions stored in the memory 403 to implement the data transmission methods provided in the following embodiments of the present application.

[0123] Optionally, the computer instructions in this embodiment of the present application may also be referred to as application program code, which is not particularly limited in this embodiment of the present application.

[0124] During specific implementation, in an embodiment, the processor 401 may include one or more CPUs, for example, CPU0 and CPU1 in FIG.

[0125] In a specific implementation, in an embodiment, communication device 400 may include multiple processors, such as processor 401 and processor 408 of FIG. 4. Each of the processors may be a single-core (single-CPU) processor or a multi-core (multi-CPU) processor. A processor herein may be one or more devices, circuits, and processing cores configured to process data (e.g., computer instructions).

[0126] During specific implementation, in an embodiment, the communication device 400 may further include an output device 405 and an input device 406. The output device 405 communicates with the processor 401 and may display information in multiple ways.

[0127] For example, the CU and / or DU in Fig. 1 in this embodiment of the present application may alternatively be implemented by the communication device 500 in Fig. 5. The communication device 500 includes a processing module 501 and a communication module 502.

[0128] In this embodiment, communication device 500 is provided by incorporating functional modules obtained by division, where the modules may be ASICs, circuits, processors executing one or more software or firmware programs, memory, integrated logic circuits, and / or other components capable of providing the functionality described above. In a simple embodiment, one skilled in the art may envision that communication device 500 may take the form of communication device 400 shown in FIG. 4.

[0129] Specifically, the functions / implementation processes of the communication module 502 and the processing module 501 in Figure 5 may be implemented by the processor 401 in the communication device 400 shown in Figure 4 by invoking computer instructions stored in the memory 403. Alternatively, the functions / implementation processes of the processing module 501 in Figure 4 may be implemented by the processor 401 in the communication device 400 shown in Figure 4 by invoking computer instructions stored in the memory 403, and the functions of the communication module 502 in Figure 5 may be implemented by the communication interface 404 in the communication device 400 shown in Figure 4.

[0130] The communication device 500 provided in this embodiment can implement the data transmission method described below, so please refer to the method embodiment below for the technical effects that can be achieved by the communication device 500. The details will not be described again here.

[0131] It should be noted that the above modules can be implemented by software, hardware, or a combination thereof. When any one of the above modules is implemented by software, the software exists in the form of computer program instructions and is stored in a memory. A processor is configured to execute the program instructions and implement the above method procedures. The processor may be configured within a system-on-a-chip (SoC) or an ASIC, or may be an independent semiconductor chip. In addition to the cores used to execute software instructions and perform operations or processes, the processor may further include required hardware accelerators such as a field programmable gate array (FPGA), a programmable logic device (PLD), or logic circuits that implement dedicated logical operations.

[0132] When the above modules are implemented using hardware, the hardware may be any one or any combination of a CPU, microprocessor, digital signal processing (DSP) chip, microcontroller unit (MCU), artificial intelligence processor, ASIC, SoC, FPGA, PLD, dedicated digital circuitry, hardware accelerator, or non-integrated discrete device, and the hardware may execute necessary software or may be software-independent to perform the method procedures described below.

[0133] It should be noted that in the embodiments of the present application, the names of functions, network elements, or information between devices, the names of parameters in the information, etc. are merely examples. In specific implementations, the names may be other names. This is not particularly limited in the embodiments of the present application.

[0134] In the following, unless otherwise specified, the meanings expressed by terminal device and user equipment are the same, and the meanings expressed by access network device and base station are the same.

[0135] To facilitate understanding by those skilled in the art, the following describes some technical terms and related concepts.

[0136] 1.MBS transmission

[0137] A multimedia broadcast multicast service (MBMS) or multicast broadcast service (MBS) is a service directed to multiple UEs, such as a live broadcast service or scheduled program playback.

[0138] Multicast transmission technology is a technology in which an access network device transmits MBS data to multiple UEs simultaneously. The MBS data may be transmitted to the UEs by the network device in a unicast manner by establishing a dedicated bearer for the UE, or may be transmitted to the UE in a multicast manner by establishing a dedicated bearer for the MBS. If multiple UEs need to receive the MBS data, if the service is transmitted in a unicast manner, dedicated bearers need to be established for multiple UEs, consuming resources. If the service is transmitted to the UEs in a multicast manner, a dedicated bearer for the MBS can be established, and all UEs interested in the MBS can receive the MBS through the dedicated bearer for the MBS, thereby saving air interface resources, improving spectrum utilization, and increasing transmission rates.

[0139] For example, Figure 6 shows a process of transmitting MBS data. As shown in Figure 6, the MBS data is from a data server. First, the server sends the MBS data to a core network, then the core network sends the MBS data to an access network device, and finally, the access network device sends the MBS data to at least one UE.

[0140] For an access network device that supports MBS, there are two transmission modes for MBS data to be transmitted from the access network device to the UE. The first transmission mode is the point-to-multipoint (PTM) transmission mode, and the second transmission mode is the point-to-point (PTP) transmission mode. The PTM transmission mode can also be called a group scheduling scheme or multicast transmission mode.

[0141] 2.PTM transmission mode

[0142] The PTM transmission mode is a transmission mode in which a network device transmits data of a service to multiple terminal devices simultaneously. When PTM transmission is used, when an access network device (e.g., a base station) transmits data for the same data, multiple terminal devices receive the data simultaneously.

[0143] 3.PTP transmission mode

[0144] The PTP transmission mode is a transmission mode in which an access network device transmits service data to a terminal device. When PTP transmission is used, for the same data, the access network device (e.g., a base station) establishes a separate transmission channel with each terminal device and then transmits the data to each terminal device individually.

[0145] 4. RLC Entity Transmission Mode

[0146] In the radio protocol stack, the transmission modes of the RLC entity included in the RLC layer include the following three types:

[0147] (1) Transparent mode (TM): The RLC entity does not process data and only provides a pass-through of data. An RLC entity using this transmission mode is called a TM RLC entity (or TM entity for short).

[0148] (2) Unacknowledged mode (UM): The RLC entity provides all RLC functions except for retransmission and resegmentation. Even if an error occurs during data packet transmission, the RLC entity in this transmission mode does not have the retransmission function and can only provide unreliable transmission services. An RLC entity using this transmission mode is called a UM RLC entity (or UM entity for short). When a network device transmits data to a terminal device in PTM mode, the RLC entity supports UM transmission, which is called RLC UM for short.

[0149] (3) Acknowledged mode (AM): The RLC entity provides all RLC functions, including ARQ functionality. The RLC entity provides reliable transmission services through error detection and retransmission. An RLC entity using this transmission mode is called an AM RLC entity (abbreviated as AM entity). When a network device transmits data to a terminal device in PTP mode, the RLC entity supports UM transmission or AM transmission, which is abbreviated as RLC UM or RLC AM.

[0150] 5. Different frame formats of packet headers of data packets transmitted between CU and DU

[0151] Currently, when user plane data (e.g., PDCP PDU) is transmitted between a CU and a DU, three different frame formats of the packet header of a data packet are specified in the existing protocol to help the CU perform data flow control for the transmission of the user plane data packet, in other words, to help the CU control the process of user plane data transmission and prevent data loss. The DU can feedback information such as packet loss, retransmission, and sending of acknowledgment to the CU based on the data packet header frame in the different formats, so that the CU can perform data flow control based on the feedback information. For example, the data packet header frame in the different formats provides the following specific functions: (1) Providing NR user (U) specific sequence number (SN) information for user data transmitted from a node carrying NR PDCP to a corresponding node of a specific data radio bearer; (2) information about the success of the continuous delivery of NR PDCP PDUs from the corresponding node to the UE for user data associated with a particular data radio bearer; (3) Information about NR PDCP PDUs that were not delivered to the UE or sent to lower layers; (4) Information of the NR PDCP PDU of user data associated with a particular data radio bearer; (5) Information of downlink NR PDCP PDUs to be discarded for user data associated with a particular data radio bearer; (6) information about the current desired buffer size at the corresponding node for transmitting user data associated with a particular data radio bearer to the UE; (7) information of the current desired data rate (in bytes) at the corresponding node for transmitting user data associated with a particular data radio bearer to the UE; (8) Information regarding the success of the continuous delivery mode of the NR PDCP PDU from the corresponding node to the UE for retransmission of user data associated with a specific data radio bearer; (9) Information of the NR PDCP PDU sent to lower layers for retransmission of user data associated with a particular data radio bearer; (10) Information on specific events at corresponding nodes; (11) information about the radio link quality from the corresponding node for the transmission of user data associated with a particular data radio bearer; and (12) Information about QoS for monitoring user data associated with a particular data radio bearer from a corresponding node.

[0152] For example, Table 1, Table 2, and Table 3 show specific different frame formats for the packet header of a data packet. [Table 1]

[0153] (1) PDU Type: Indicates the type of the PDU data packet, where 0 indicates that the data packet is downlink user data.

[0154] (2) Spare: Indicates a reserved field.

[0155] (3) DL Discard Blocks: Indicates a block packet loss flag. 0 indicates that the DL Discard Block Count field, DL Discard NR PDCP PDU SN Start (First Block) field, and Discard Block Size (Last Block) field are not present, and 1 indicates that the DL Discard Block Count field, DL Discard NR PDCP PDU SN Start (First Block) field, and Discard Block Size (Last Block) field are present.

[0156] (4) DL Flush: 0 indicates that the DL Discard NR PDCP PDU SN field is not present, and 1 indicates that the DL Discard NR PDCP PDU SN field is present.

[0157] (5) ReportPolling: Indicates the polling flag. 0 indicates that the peer node does not need to respond with a status report, and 1 indicates that the peer node needs to respond with a status report.

[0158] (6) Support Information Report Polling Flag: 0 indicates that the peer end does not need to respond with support information data, and 1 indicates that the peer end needs to respond with support information data.

[0159] (7) Retransmission flag: A retransmission flag that indicates whether the NR-U packet is a retransmitted packet.

[0160] (8) NR-U Sequence Number: Indicates the NR-U SN allowed by PDCP.

[0161] (9) DL Discard NR PDCP PDU SN: When DL Flush is 1, this field is present and indicates that PDCP requires all packets before the PDCP SN number to be discarded.

[0162] (10) Number of DL Discarded Blocks: When DL Discarded Blocks is 1, this field is present and indicates the number of blocks to be discarded.

[0163] (11) DL Discard NR PDCP PDU SN Start: When DL Discard Block is 1, this field is present and indicates that PDCP requires that the number of packets up to the Discard Block Size, starting from (and including) the SN number, be discarded.

[0164] (12) Discard Block Size: When DL Discard Block is 1, this field is present and indicates the number of packets to be discarded. [Table 2]

[0165] (1) PDU type: 1 indicates that the data packet is a Downlink Data Delivery Status (DDDS).

[0166] (2) Desired buffer size for related DRB: indicates the desired DU buffer size for the related data radio bearer (DRB). Desired data rate: indicates the desired data rate for the DRB, i.e., the desired data rate of the UE associated with the DRB. The two pieces of information can be used to assist the CU in performing data flow control. After receiving the data frame DDDS shown in Table 2, the CU continues to transmit PDCP PDUs with the desired bits to the DU based on the two pieces of information in the data frame and the highest SN of the PDCP PDUs currently present in the DU until the CU next receives the DDDS.

[0167] (3) Successfully Delivered NR PDCP Sequence Number: Indicates the highest SN of the NR PDCP PDU that the CU successfully transmitted to the UE. This information may be specifically indicated as the information described in the following (i) and (ii).

[0168] (i) Highest NR PDCP PDU sequence number (AM) successfully delivered in order to the UE: Indicates the highest SN of the NR PDCP PDU that the DU successfully delivered in order to the UE, and AM indicates that the DU transmits the PDCP PDU to the UE by using RLC AM.

[0169] (ii) Number / Start / End of Successfully Delivered Out-of-Order PDCP Sequence Number Ranges (AM): Indicates the number / Start SN / End SN of NR PDCP PDUs that the DU successfully delivered to the UE out of order, and AM indicates that the DU transmits PDCP PDUs to the UE by using RLC AM.

[0170] (4) Transmitted NR PDCP sequence number: Indicates the NR PDCP PDU successfully transmitted by the UE. This information may be specifically indicated as the information described in the following (iii).

[0171] (iii) Highest NR PDCP PDU Sequence Number (UM) transmitted to lower layer: Indicates the highest SN number of the NR PDCP PDU that the DU successfully transmitted to the lower layer, where the lower layer refers to the MAC layer and the physical layer. UM indicates that the DU transmits the PDCP PDU to the UE using RLC UM.

[0172] The information in (i), (ii) and (iii) may also be used to assist the CU in performing data flow control.

[0173] (5) Number / Start / End of "Lost" NR-U Packets: Indicates the number / Start SN / End SN of lost NR-U data packets. This information is introduced to avoid desynchronization of NR PDCP hyperframe numbers (HFNs) between UEs.

[0174] (6) Successfully delivered retransmitted NR PDCP sequence number: Indicates the SN of the NR PDCP PDU that the DU successfully retransmitted to the UE. Retransmitted NR PDCP sequence number: Indicates the SN of the NR PDCP PDU that the DU retransmitted to the lower layer. Based on these two messages, the CU can determine the specific PDCP PDU that the DU retransmitted to the UE or to the lower layer. [Table 3]

[0175] PDU type: 2 indicates that the data packet is aiding information data.

[0176] The information may be used to assist the CU in adjusting the procedure for transmitting PDCP PDUs to the UE. For example, the CU may adjust the procedure for transmitting PDCP PDUs to the UE based on the assistance information in the following cases:

[0177] (1) A corresponding node (e.g., DU) sends radio link quality support information of the relevant DRB and / or a proposal to activate PDCP duplication to a node (e.g., CU) carrying an NR PDCP entity.

[0178] (2) The corresponding node sends the radio link quality assistance information of the associated RLC entity to the node carrying the NR PDCP entity.

[0179] The quality support information in (1) and (2) may further include uplink (UL) delay information and / or downlink (DL) delay information measured by a corresponding node (e.g., DU).

[0180] The above describes the technical terms and related concepts in the embodiments of the present application, and the details will not be described again below.

[0181] In this embodiment of the present application, the F1 scenario is a scenario in which a CU of a base station communicates with a DU of the base station, and the X2 scenario is a scenario in which a CU of a base station communicates with a DU of another base station. In the above scenarios, to ensure data transmission reliability, when receiving an NR-U data packet transmitted by a DU, the RLC entity of the DU manages the NR-U SN number, i.e., the SN number of the PDCP PDU, using a receive window. For example, the RLC entity of the DU can keep up to 1024 out-of-order SN bits using the receive window.

[0182] In addition, the DU further reports the DDDS to the CU, so that the CU performs data flow control on data packets sent to the DU. Currently, the DU can report the DDDS to the CU in the following three ways:

[0183] Method 1: When a DU uses RLC UM to send a new radio-user (NR-U) data packet (i.e., a PDCP PDU) to a terminal device, after the DU receives information indicating successful packet assembly at the MAC layer, the DU sends an NR-U status report, i.e., a DDDS, to the PDCP entity of the CU. Furthermore, the DU also starts a periodic timer and periodically sends a DDDS to the CU.

[0184] Method 2: DU is RLC A M When using the DD-U protocol to transmit an NR-U packet to a terminal device, after receiving a feedback report from the terminal device, the RLC entity of the DU sends a DDDS to the PDCP entity of the CU. Furthermore, the DU also starts a periodic timer and periodically transmits a DDDS to the CU.

[0185] Method 3: When receiving a polling packet sent by the CU, the DU immediately sends a DDDS to the CU.

[0186] Currently, when MBS data is transmitted in a CU-DU architecture, the CU reports the DDDS to the DU in two ways.

[0187] Method A: A GTP-U tunnel shared by multiple terminal devices and a GTP-U tunnel dedicated to a single terminal device are established between the CU and the DU. Currently, at least when the DU transmits data to multiple terminal devices in PTM mode, the CU sends an MBS data packet to the DU via the shared GTP-U tunnel, and the data packet includes an MBS data PDCP PDU and a packet header downlink user data (DL USER DATA) (i.e., PDU type 0 shown in Table 1). The DU feeds back the DDDS of each terminal device (i.e., PDU type 1 shown in Table 2) to the CU via a dedicated GTP-U tunnel.

[0188] Method B: A GTP-U tunnel shared by multiple terminal devices and a GTP-U tunnel dedicated to a single terminal device are established between the CU and the DU. Currently, at least when the DU transmits data to multiple terminal devices in PTM mode, the CU sends an MBS data packet to the DU through the shared GTP-U tunnel, and the data packet includes an MBS data PDCP PDU and a packet header DL USER DATA. The DU feeds back the DDDS of each terminal device to the CU through the shared GTP-U tunnel. In this way, the DDDS report fed back by the DU to the CU carries the index of the terminal device, so that the CU can determine the terminal device to which the DDDS belongs and then retransmit the PDCP PDU to that terminal device.

[0189] The DDDS is reported to the DRB of the terminal in both Method A and Method B. For different terminal devices, the CU allocates different DRBs. That is, the DDDS is reported to a single terminal device in both Method A and Method B. When a DU transmits a PDCP PDU to a terminal device by using RLC UM, the DU generates a DDDS after transmitting the PDCP PDU transmitted to the terminal device to a lower layer, and the DDDS indicates the space in the DU's buffer and / or the status of PDCP PDUs lost at the F1 interface. When a DU transmits a PDCP PDU to a terminal device by using RLC AM, the DU generates a DDDS after transmitting the PDCP PDU to the terminal device and receiving feedback from the terminal device, and the DDDS indicates the reception status of the PDCP PDU of the terminal device. Then, the DU transmits the DDDS to the CU to notify the transmission status of the PDCP PDU and the space in the DU's buffer, so that the CU then transmits data to the DU's buffer.

[0190] Note that for an MBS, the data of the MBS transmitted to multiple terminal devices is the same. The CU transmits a PDCP PDU to the DU via the F1 interface, and the DU stores the received PDCP PDU in a buffer and then transmits the PDCP PDU to multiple terminal devices in PTM and / or PTP mode. In this case, the data packets received by the multiple terminal devices are the same data packets stored in the DU. When RLC UM is used, the DDDS generated by the DU is independent of the terminal device. As a result, when the DU transmits the DDDS to the CU using Method A or Method B, repeated signaling overhead occurs, causing resource waste. When RLC AM is used, the DU individually reports the DDDS of each terminal device using Method A or Method B, which also causes large signaling overhead and resource waste.

[0191] In order to solve the above technical problems, the embodiments of the present application provide a data transmission method. The data transmission method provided in the embodiments of the present application will be described below with reference to the accompanying drawings.

[0192] In this application, the DU receives at least one PDCP PDU from the CU, where the at least one PDCP PDU carries data of an MBS. The DU transmits the at least one PDCP PDU to at least two terminal devices. The DU then transmits a status report to the CU. The status report is obtained by the DU by combining results of transmitting the PDCP PDUs to multiple (at least two) terminal devices. The mode in which the DU transmits the at least one PDCP PDU to the at least two terminal devices may include any one or more of the following: RLC UM, RLC AM, PTM, PTP, etc.

[0193] 7 illustrates a data transmission system according to an embodiment of the present application. The method includes the following steps:

[0194] S701: A CU sends a first PDCP PDU to a DU. In response, the DU receives the first PDCP PDU sent by the CU.

[0195] In step S701, the operations performed by the CU may be performed by the communication interface 404 of the communication device 400 and the communication module 502 of the communication device 500. Alternatively, the operations performed by the DU may be performed by the communication interface 404 of the communication device 400 and the communication module 502 of the communication device 500.

[0196] The first PDCP PDU carries data of the MBS, and may be one or more PDCP PDUs, which is not a limitation of the present application.

[0197] The CU may transmit the first PDCP PDU to the DU via the F1 channel. Correspondingly, the DU may receive the first PDCP PDU transmitted by the CU via the F1 channel. The F1 channel includes a GTP-U tunnel shared by multiple terminal devices and a GTP-U tunnel dedicated to a single terminal device. The tunnel used by the CU to transmit the first PDCP PDU to the DU is not particularly limited in this application.

[0198] S702: The DU sends a first PDCP PDU to at least two terminal devices.

[0199] In step S702, the operations performed by the DU may be performed by the communication interface 404 of the communication device 400 and the communication module 502 of the communication device 500.

[0200] After receiving the first PDCP PDU, the DU stores the first PDCP PDU in a buffer of the DU, and transmits the processed first PDCP PDU to at least two terminal devices.

[0201] Optionally, the DU may send the first PDCP PDU to at least two terminal devices in the following design.

[0202] Design 1: A DU transmits a first PDCP PDU to at least two terminal devices by using RLC UM. Note that when a DU transmits data to a terminal device in PTM mode, only RLC UM is supported in that mode. When a DU transmits data to a terminal device in PTP mode, both RLC AM and RLC UM may be supported in that mode. Therefore, in this design, a DU transmitting a first PDCP PDU to at least two terminal devices by using RLC UM includes a case where a DU transmits a first PDCP PDU to at least two terminal devices in PTM mode and PTP mode that support RLC UM.

[0203] Design 2: A DU sends a first PDCP PDU to at least two terminal devices in PTM mode.

[0204] Design 3: The DU transmits the first PDCP PDU by using RLC AM to a first terminal device among the at least two terminal devices, where the first terminal device includes at least one terminal device; and the DU transmits the first PDCP PDU by using RLC UM to a second terminal device among the at least two terminal devices, where the second terminal device includes at least one terminal device.

[0205] Design 4: The DU transmits the first PDCP PDU in a PTM mode to a first terminal device among the at least two terminal devices, the first terminal device including at least one terminal device, and the DU transmits the first PDCP PDU in a PTP mode to a second terminal device among the at least two terminal devices, the second terminal device including at least one terminal device.

[0206] Optionally, the mode in which the DU transmits the first PDCP PDU to the at least two terminal devices may be determined independently by the CU, or independently by the DU, or jointly by the DU and the CU.

[0207] S703: The DU sends a status report to the CU. In response, the CU receives the status report sent by the DU.

[0208] In step S703, the operations performed by the CU may be performed by the communication interface 404 of the communication device 400 and the communication module 502 of the communication device 500. Alternatively, the operations performed by the DU may be performed by the communication interface 404 of the communication device 400 and the communication module 502 of the communication device 500.

[0209] The status report indicates the result of the transmission of the first PDCP PDU to at least two terminal devices. In other words, the status report is obtained by the DU by "combining" the results of the transmission of the first PDCP PDU to at least two terminal devices. The status report may also be referred to as a DDDS, although this is not a limitation in the present application.

[0210] For ease of description, the "result of the transmission of the first PDCP PDU" is referred to as the "transmission result" for short. Note that "combined" means that the status report is a "transmission result" determined by the DU based on the "transmission results" of each of the at least two terminal devices to indicate the transmission results of the at least two terminal devices. "Combined" does not mean simply listing the "transmission results" of the at least two terminal devices in one status report to indicate the transmission results of the at least two terminal devices.

[0211] For example, the first PDCP PDU is three PDCP PDUs, and SN1 to SN3 identify three PDCP PDUs. For example, the at least two terminal devices are three terminal devices, and the three terminal devices are UE1 to UE2. 3 is identified by

[0212] The frame structure described in Table 2 above is used as an example. It is assumed that the DU transmits SN1 to SN3 from UE1 to UE3 in PTM mode. It is assumed that SN1 and SN2 successfully transmit to the three terminal devices, but SN3 fails to transmit to UE2. In this case, the "combined" status report carries the "highest transmitted NR PDCP sequence number" filled with "SN#2". Note that "SN#2" means that the SN number is 2. This is described uniformly here and will not be described in detail again below. In this way, the transmission results of SN1 to SN3 to the three terminal devices are shown.

[0213] In the above case, the "combined" status report is filled with "Highest Transmitted NR PDCP Sequence Number" filled with "SN#3" to indicate the result of transmission from SN1 to SN3 to UE1, and "SN#" to indicate the result of transmission from SN1 to SN3 to UE2. 2 " the highest transmitted NR PDCP sequence number" filled in with "SN#" to indicate the result of transmission from SN1 to SN3 to UE3. 3 Instead of carrying the "highest transmitted NR PDCP sequence number" that is filled with ".

[0214] Based on the above technical problem, when a DU receives a first PDCP PDU from a CU, and the first PDCP PDU carries data of an MBS, the DU transmits the first PDCP PDU to at least two terminal devices and transmits a status report to the CU, where the status report indicates a result of transmitting the first PDCP PDU to the at least two terminal devices. Thus, when the data of the MBS is transmitted, the signaling overhead for reporting the status report is reduced and resources are saved.

[0215] Optionally, the DU may send a status report to the CU via the first channel. Correspondingly, the CU receives the status report sent by the DU via the first channel. The first channel is a GTP-U tunnel shared by multiple terminal devices.

[0216] Optionally, the DU may send a status report to the CU via a second channel. Correspondingly, the CU receives the status report sent by the DU via the second channel. The second channel is a GTP-U tunnel dedicated to a single terminal device.

[0217] The status report indicates the result of transmitting the first PDCP PDU to each of at least two terminal devices. For example, there are three terminal devices. The DU transmits the first PDCP PDU to the three terminal devices, and the status report indicates the result of transmitting the first PDCP PDU to the three terminal devices.

[0218] Optionally, the status report may be a status report of multiple terminal devices with relatively low priority, i.e., at least two terminal devices are terminal devices with relatively low priority. For terminal devices with relatively high priority or terminal devices whose transmission results are marked as "cannot be combined with transmission results of other terminal devices", the above method of "DDDS reporting for a single terminal device" may be used. This is not a limitation in the present application.

[0219] The following specifically describes the design of step S702 and the status report based on the frame format shown in Table 2.

[0220] When the above design 1 is used, the status report is an "RLC UM" status report. RLC UM is the mode used when a DU transmits the first PDCP PDU to a terminal device, and for ease of description, this form is used for expression. This is uniformly described here and will not be described again in detail below. The status report indicates the result of the DU transmitting the first PDCP PDU to each of at least two terminal devices by using RLC UM.

[0221] For example, the at least two terminal devices are five terminal devices, UE1 to UE5 identify the five terminal devices, the first PDCP PDU is the five PDCP PDUs, and SN1 to SN5 identify the five PDCP PDUs.

[0222] In this case, the DU transmits SN1, SN2, SN3, SN4, and SN5 to UE1, UE2, UE3, UE4, and UE5 by using RLC UM. SN1 and SN2 successfully transmit to the five UEs, but SN3 only successfully transmits to UE3 and UE5 and fails to transmit to the remaining three terminal devices. In this case, the frame format of the status report may include a "highest transmitted NR PDCP sequence number" field filled with "SN#2." In other words, the status report indicates the result of the DU transmitting the first PDCP PDU to the five terminal devices by using RLC UM.

[0223] If design 2 above is used, the status report is a "PTM" status report and indicates the result of the DU transmitting the first PDCP PDU in PTM mode to each of the at least two terminal devices.

[0224] The above example is still used for description. In this case, the frame format of the status report may include a "Highest Transmitted NR PDCP Sequence Number" field filled with "SN#2". In other words, the status report indicates the result of the DU transmitting the first PDCP PDU to five terminal devices in PTM mode.

[0225] When design 3 above is used, the status report is an “RLC AM and RLC UM” status report and indicates the result of the transmission of the first PDCP PDU to the first terminal device and the result of the transmission of the first PDCP PDU to the second terminal device.

[0226] An example in which the at least two terminal devices are five terminal devices is still used. UE1 to UE5 identify the five terminal devices, the first PDCP PDU is the five PDCP PDUs, and SN1 to SN5 identify the five PDCP PDUs. For example, the first terminal devices are UE1, UE3, and UE4, and the second terminal devices are UE2 and UE5.

[0227] For example, in this case, the DU transmits SN1, SN2, SN3, SN4, and SN5 to UE1, UE3, and UE4 by using RLC AM, and transmits SN1, SN2, SN3, SN4, and SN5 to UE2 and UE5 by using RLC UM. It is assumed that when the DU uses RLC AM, SN1, SN2, and SN3 are successfully transmitted to UE1, UE3, and UE4, SN4 is only successfully transmitted to UE3, and SN5 is only successfully transmitted to UE4. When the DU uses RLC UM, SN1 and SN2 are successfully transmitted to UE2 and UE5, but SN3 and SN5 are only successfully transmitted to UE2, and SN4 is only successfully transmitted to UE5. Therefore, in this case, the status report is filled with "Highest Delivery Successful NR PDCP Sequence" filled with "SN#2". S number The NR PDCP Sequence Number field may contain the "Highest Transmitted NR PDCP Sequence Number" field, which is filled with "SN#4".

[0228] For example, in this case, DU: RLC SN1 to SN5 are transmitted to UE1, UE3, and UE4 by using AM, and SN1 to SN5 are transmitted to UE2 and UE5 by using RLC UM. SN1, SN2, SN3, and SN4 are successfully transmitted from UE1 to UE5, and SN 5 It is assumed that UE3 and UE4 are successful in transmitting to UE1, UE2, and UE5, but are unsuccessful in transmitting to UE1, UE2, and UE5. Therefore, in this case, a new field, e.g., "Highest Successful NR PDCP Sequence Number" can be added. S number The "Highest Successfully Delivered NR PDCP Sequence Number" field may be defined in the frame format described in Table 3 above, where the field is filled with "SN#4" to indicate that the highest SN of the current first PDCP PDU successfully transmitted to at least two terminal devices is 4. Alternatively, an existing field in the frame format shown in Table 2, e.g., "Highest Successfully Delivered NR PDCP Sequence Number" field may be filled with "SN#4" to indicate that the highest SN of the current first PDCP PDU successfully transmitted to at least two terminal devices is 4. S number The "Highest Transmitted NR PDCP Sequence Number" or "Highest Transmitted NR PDCP Sequence Number" may be reused, and the field filled with "SN#4" to indicate that the highest SN of the current first PDCP PDU successfully transmitted to at least two terminal devices is 4.

[0229] It should be noted that the frame format of the status report, the fields included in the frame format, and the corresponding filling method are not particularly limited in this application, which are uniformly described here and will not be described in detail again below.

[0230] When the above design 4 is used, there are specific cases of designs 5 and 6 described below.

[0231] Design 5: The status report is a "PTP and PTM" status report, indicating the result of the transmission of the first PDCP PDU to the first terminal device and the result of the transmission of the first PDCP PDU to the second terminal device.

[0232] Optionally, in this design, the status report may carry indication information to indicate that the status report is a "PTP and PTM" status report.

[0233] For example, the indication information may be implemented by reusing the current index (which may also be called an indication) in the frame format shown in Table 2, such as "Highest NR PDCP SN Index Delivered" and "Highest NR PDCP SN Index Transmitted," or by newly defining the "PTP and PTM" index. The specific implementation of the indication information is not particularly limited in this application.

[0234] An example in which the at least two terminal devices are five terminal devices is still used. UE1 to UE5 identify the five terminal devices, the first PDCP PDU is the five PDCP PDUs, and SN1 to SN5 identify the five PDCP PDUs. For example, the first terminal devices are UE1, UE3, and UE4, and the second terminal devices are UE2 and UE5. In this case, the DU transmits SN1, SN2, SN3, SN4, and SN5 to UE1, UE3, and UE4 in PTP mode, and transmits SN1, SN2, SN3, SN4, and SN5 to UE2 and UE5 in PTM mode.

[0235] It is assumed that if the DU uses PTP, SN1, SN2, and SN3 successfully transmit to UE1, UE3, and UE4, SN4 only successfully transmits to UE3, and SN5 only successfully transmits to UE4. If the DU uses PTM, SN1 and SN2 successfully transmit to UE2 and UE5, but SN3 and SN5 only successfully transmit to UE2, and SN4 only successfully transmits to UE5. Thus, in this case, the status report may include the "Highest Successfully Delivered NR PDCP Sequence Number" field filled with "SN#2" and the "Highest Transmitted NR PDCP Sequence Number" field filled with "SN#4." Note that this method requires prior agreement that the "highest successfully delivered NR PDCP sequence number" represents a field that is filled when a DU transmits its first PDCP PDU to a terminal device in PTP mode, and the "highest transmitted NR PDCP sequence number" represents a field that is filled when a DU transmits its first PDCP PDU to a terminal device in PTM mode. Alternatively, the status report may include the "highest successfully delivered NR PDCP sequence number" field filled with "SN#4" and the "highest transmitted NR PDCP sequence number" field filled with "SN#2." Note that this method also requires prior agreement that the "highest successfully delivered NR PDCP sequence number" represents a field that is filled when a DU transmits its first PDCP PDU to a terminal device in PTM mode, and the "highest transmitted NR PDCP sequence number" represents a field that is filled when a DU transmits its first PDCP PDU to a terminal device in PTP mode.

[0236] Accordingly, it should be noted that the specific fields that are specifically agreed to be filled in when the DU transmits the first PDCP PDU to the terminal device in PTP mode, and the specific fields that are specifically agreed to be filled in when the DU transmits the first PDCP PDU to the terminal device in PTM mode, are not particularly limited in this application.

[0237] Alternatively, whether a field is filled when a DU transmits the first PDCP PDU to a terminal device in PTP mode or when a DU transmits the first PDCP PDU to a terminal device in PTM mode may be indicated by another indication method. For example, a bit may be used for the indication, with "0" representing PTM mode and "1" representing PTP mode. Optionally, the specific field to which the additional indication is added and the indication method are not limited by this application.

[0238] Alternatively, new fields may be defined in the frame format shown in Table 2, such as "Highest Successfully Transmitted NR PDCP Sequence Number for PTP" to instruct the DU to transmit the first PDCP PDU to the first terminal device in PTP mode, and / or "Highest Successfully Transmitted NR PDCP Sequence Number for PTM" to instruct the DU to transmit the first PDCP PDU to the second terminal device in PTM mode.

[0239] For example, in this case, SN1 to SN5 are transmitted to UE1, UE3, and UE4 by using PTP, and SN1 to SN5 are transmitted to UE2 and UE5 by using PTM. SN1, SN2, SN3, and SN4 are transmitted from UE1 to UE5 successfully, and SN 5 It is assumed that UE3 and UE4 are successful in transmitting to UE1, UE2, and UE5, but are unsuccessful in transmitting to UE1, UE2, and UE5. Therefore, in this case, a new field, e.g., "Highest Successful NR PDCP Sequence Number" can be added. S number The "Highest Successfully Delivered NR PDCP Sequence Number" field may be defined in the frame format described in Table 3 above, where the field is filled with "SN#4" to indicate that the highest SN of the current first PDCP PDU successfully transmitted to at least two terminal devices is 4. Alternatively, an existing field in the frame format shown in Table 2, e.g., "Highest Successfully Delivered NR PDCP Sequence Number" field may be filled with "SN#4" to indicate that the highest SN of the current first PDCP PDU successfully transmitted to at least two terminal devices is 4. S numberThe "Highest Transmitted NR PDCP Sequence Number" or "Highest Transmitted NR PDCP Sequence Number" may be reused, and the field filled with "SN#4" to indicate that the highest SN of the current first PDCP PDU successfully transmitted to at least two terminal devices is 4.

[0240] Design 6: The status report is a "PTM" status report and indicates only the result of the transmission of the first PDCP PDU to the first terminal device. Specifically, in this design, the DU combines only the transmission result of the first terminal device that transmitted the first PDCP PDU in PTM mode, and does not combine the transmission result of the second terminal device that transmitted the first PDCP PDU in PTP mode. It may be understood that "used only" in the embodiments of the present application is a relative concept with respect to the first terminal device and the second terminal device. For example, "used only" for the first terminal device means that it is not used for the second terminal device. The above description does not exclude the status report from including other information.

[0241] For example, in this design, the frame format of the status report may be the same as the frame format of the status report in above Design 2. The details will not be described again here.

[0242] It should be noted that the frame format of the status report and the manner and / or content of filling the relevant fields in the frame format are merely examples for description and do not constitute specific limitations on the status report. The status report may alternatively indicate corresponding information based on another field. This is not limited in this application and is uniformly described here. Details will not be described below.

[0243] Optionally, when the DU transmits the first PDCP PDU to the second terminal device by using PTP, one status report may indicate the result of transmitting the first PDCP PDU to the second terminal device, or the result of transmitting the first PDCP PDU to each terminal device included in the second terminal device may be indicated individually by a status report, i.e., in the above-mentioned manner of "DDDS Report for a Single Terminal Device." In this design, the status report of the second terminal device is not particularly limited in this application.

[0244] Optionally, if the DU indicates the result of transmitting the first PDCP PDU to the second terminal device in the above-described manner of "Reporting a DDDS for a Single Terminal Device," and the DU transmits a status report to the CU via shared GTP-U, the status report can carry an index number of the terminal device, thereby allowing the CU to identify the second terminal device to which the status report belongs. For example, the index number may be expressed in the following manner: when the status report is first transmitted, the UE ID and the indication sequence number may be carried to inform the CU that the UE ID corresponds to the indication sequence number. When the status report is transmitted again, only the indication sequence number is carried. In this way, the CU can directly determine the terminal device to which the status report belongs based on the indication sequence number, thereby reducing signaling overhead. Alternatively, the index number may be expressed in a manner that the indication sequence number is agreed upon in advance. For example, the CU, DU, and UE share one indication sequence number to represent the UE ID. The specific expression method of the UE index is not limited by this application.

[0245] When the above design 3 and / or the above design 5 are used, step S703 may also be specifically implemented as a subsequent step.

[0246] Step S703a: The DU sends a first status report to the CU. Correspondingly, the CU receives the first status report sent by the DU.

[0247] In step S703a, the operations performed by the CU may be performed by the communication interface 404 of the communication device 400 and the communication module 502 of the communication device 500. Alternatively, the operations performed by the DU may be performed by the communication interface 404 of the communication device 400 and the communication module 502 of the communication device 500.

[0248] The first status report indicates the result of the transmission of the first PDCP PDU to the first terminal device.

[0249] Step S703b: The DU sends a second status report to the CU. Correspondingly, the CU receives the second status report sent by the DU.

[0250] In step S703b, the operations performed by the CU may be performed by the communication interface 404 of the communication device 400 and the communication module 502 of the communication device 500. Alternatively, the operations performed by the DU may be performed by the communication interface 404 of the communication device 400 and the communication module 502 of the communication device 500.

[0251] The second status report indicates the result of the transmission of the first PDCP PDU to the second terminal device.

[0252] Specifically, the status report may be specifically implemented as a first status report and a second status report, and the DU may separately send the first status report and the second status report to the CU. Note that the order of step S703a and step S703b may be interchanged. The order in which the DU sends the first status report and the second status report to the CU is not particularly limited in this application.

[0253] Optionally, based on the above Design 3, step S703a may also be specifically implemented as a subsequent step.

[0254] S703c: The DU sends a sixth status report to the CU. In response, the CU receives the sixth status report sent by the DU.

[0255] In step S703c, the operations performed by the CU may be performed by the communication interface 404 of the communication device 400 and the communication module 502 of the communication device 500. Alternatively, the operations performed by the DU may be performed by the communication interface 404 of the communication device 400 and the communication module 502 of the communication device 500.

[0256] The sixth status report indicates a result of sequentially delivering the first PDCP PDU to at least one terminal device included in the first terminal device.

[0257] S703d: The DU sends a seventh status report to the CU. In response, the CU receives the seventh status report sent by the DU.

[0258] In step S703d, the operations performed by the CU may be performed by the communication interface 404 of the communication device 400 and the communication module 502 of the communication device 500. Alternatively, the operations performed by the DU may be performed by the communication interface 404 of the communication device 400 and the communication module 502 of the communication device 500.

[0259] The seventh status report indicates the result of out-of-order delivery of the first PDCP PDU to at least one end device included in the first end device.

[0260] It should be noted that the order of performing step S703c and step S703d may be interchanged, and the order of performing step S703c and step S703d is not particularly limited in the present application.

[0261] Optionally, related indications and information unrelated to the transmission result of the PDCP PDU to the terminal device, such as "Last Frame Index," "Cause Report," and "Cause Value" shown in Table 2, may also be included in the status report. Alternatively, related indications and information unrelated to the transmission result of the PDCP PDU to the terminal device may not be included in the status report, and the DU reports the indications and information separately to the CU. In this case, the above-mentioned individual reporting method may be used, or a method similar to the combination method in this application may be used. Furthermore, for the assistance information shown in Table 3, the above-mentioned individual reporting method may also be used, or a method similar to the combination method in this application may be used. The method of reporting partial information is not particularly limited in this application.

[0262] It should be noted that after receiving a status report, the CU needs to determine whether the status report is a status report for all terminal devices, for example, to determine whether to wait for a subsequent status report in order to perform subsequent actions.

[0263] Therefore, optionally, the first status report and the second status report may further include the following design:

[0264] Referring to Design 4 above, the first status report and the second status report may include the following Design A.

[0265] Design A: The first status report carries first indication information, and the first indication information indicates that the first status report corresponds to the PTM mode. Note that "the first status report corresponds to the PTM mode" means that the first status report is a "PTM" status report, specifically, that the first status report is a combination of status reports of terminal devices whose DUs transmit the first PDCP PDUs in the PTM mode.

[0266] In a possible implementation, the first indication information may reuse an index in Table 2, such as "Highest PDCP SN Index Transmitted" or other index, to indicate that the first status report is a "PTM" status report.

[0267] In another possible implementation, since PTM only supports RLC UM, the first indication information may use the "highest transmitted NR PDCP sequence number" field in the frame structure shown in Table 2 to implicitly indicate that the first status report is a "PTM" status report.

[0268] In yet another possible implementation, the first indication information may explicitly indicate that the first status report is a "PTM" status report by adding an additional field "PTM", e.g., a newly defined index or field.

[0269] In yet another possible implementation, the first indication information may alternatively be implemented by using other fields in the frame structure shown in Table 2 and by adding a field to the other fields to indicate that the first status report is a “PTM” status report.

[0270] The second status report carries second indication information, and the second indication information indicates that the second status report corresponds to the PTP mode. It should be noted that "the second status report corresponds to the PTP mode" means that the second status report is a "PTP" status report, specifically, that the second status report is a combination of status reports of terminal devices whose DUs transmit the first PDCP PDUs in the PTP mode.

[0271] In possible implementations, 2 The indication information may explicitly indicate that the second status report is a "PTP" status report by adding an additional field "PTP".

[0272] In another possible implementation, 2 The indication information may alternatively be implemented by using other fields in the frame structure shown in Table 2 and by adding fields to other fields to indicate that the second status report is a "PTP" status report.

[0273] For example, in design A, when the CU determines to send the first PDCP PDU to the first terminal device in PTM mode and determines to send the first PDCP PDU to the second terminal device in PTP mode, if the CU first receives the first status report, the CU can determine, based on the first indication information, that the first status report is a status report of the first terminal device, and then needs to wait for the second status report, i.e., the status report of the second terminal device; alternatively, if the CU first receives the second status report, the CU can determine, based on the second indication information, that the second status report is a status report of the second terminal device, and then needs to wait for the first status report, i.e., the status report of the first terminal device.

[0274] Referring to Design 3 above, the first status report and the second status report may include Design B below.

[0275] Design B: The first status report carries ninth indication information, and the ninth indication information indicates that the first status report corresponds to RLC AM. Note that "the first status report corresponds to RLC AM" means that the first status report is an "RLC AM" status report, specifically, that the first status report is a combination of status reports of terminal devices whose DUs transmit first PDCP PDUs by using RLC AM.

[0276] In a possible implementation, the ninth indication information is that the first status report is RLC To indicate that this is an "AM" status report, an index in Table 2, such as "Highest PDCP SN Index Transmitted," "Delivered NR PDCP SN Range Index," or other index may be reused.

[0277] In another possible implementation, the ninth indication information may use the “Highest Successfully Delivered NR PDCP Sequence Number” field in the frame structure shown in Table 2 to indicate that the first status report is an “RLC AM” status report.

[0278] In yet another possible implementation, the ninth indication information may explicitly indicate that the first status report is an “RLC AM” status report by adding an additional field “AM.” For example, an index or field may be newly defined.

[0279] In yet another possible implementation, the ninth indication information may alternatively be implemented by using other fields in the frame structure shown in Table 2 and in addition to other fields to indicate that the first status report is an “RLC AM” status report.

[0280] The second status report carries tenth indication information, which indicates that the second status report corresponds to RLC UM. Note that "the second status report corresponds to RLC UM" means that the second status report is an "RLC UM" status report, specifically, that the second status report is a combination of status reports of terminal devices in which the DU transmits the first PDCP PDU by using RLC UM.

[0281] In a possible implementation, the tenth indication information may reuse an index in Table 2, such as "highest transmitted PDCP SN index" or other index, to indicate that the second status report is an "RLC UM" status report.

[0282] In another possible implementation, the 10th indication information may use the “Highest Transmitted NR PDCP Sequence Number” field in the frame structure shown in Table 2 to indicate that the second status report is an “RLC UM” status report.

[0283] In yet another possible implementation, the tenth indication information may be provided by adding an additional field "UM" to indicate that the second status report is RLC It may explicitly indicate that it is a "UM" status report. For example, an index or field is newly defined.

[0284] In yet another possible implementation, the tenth indication information may alternatively be implemented by using other fields in the frame structure shown in Table 2 and in addition to other fields to indicate that the second status report is an “RLC UM” status report.

[0285] For example, in design B, if the CU determines to send the first PDCP PDU to the first terminal device by using RLC AM and determines to send the first PDCP PDU to the second terminal device by using RLC UM, if the CU receives the first status report first, the CU can determine, based on the first indication information, that the first status report is a status report of the first terminal device and further needs to wait for the second status report, i.e., the status report of the second terminal device; alternatively, if the CU receives the second status report first, the CU can determine, based on the second indication information, that the second status report is a status report of the second terminal device and further needs to wait for the first status report, i.e., the status report of the first terminal device.

[0286] Further, with reference to Design 3, the first status report may include the sixth status report and the seventh status report.

[0287] The sixth and seventh status reports may include the following designs a and b.

[0288] Design a: The sixth status report carries eleventh indication information, which indicates that the sixth status report is a combination of status reports of terminal devices using ordered RLC AM among the first terminal devices. The seventh status report carries twelfth indication information, which indicates that the seventh status report is a combination of status reports of terminal devices using unordered RLC AM among the first terminal devices.

[0289] The eleventh indication may use the "Highest NR PDCP PDU Sequence Number Successfully Delivered in Order to UE" field in the frame structure shown in Table 2 to indicate that the sixth status report is an "out-of-order AM" status report. Alternatively, an index in Table 2, such as the "Highest NR PDCP SN Index Delivered" or another index, may be reused to indicate that the sixth status report is an "out-of-order AM" status report. This is not a limitation of the present application.

[0290] The twelfth indication information may use the "Number / Start / End of Successfully Delivered Unordered PDCP Sequence Number Ranges" fields in the frame structure shown in Table 2 to indicate that the seventh status report is an "Unordered AM" status report. Alternatively, an index in Table 2, such as "Delivered NR PDCP SN Range Index" or another index, may be reused to indicate that the seventh status report is an "Unordered AM" status report. This is not a limitation of the present application.

[0291] Optionally, a field may be added separately to the eleventh instruction information and / or the twelfth instruction information for instructions, which is not particularly limited in the present application.

[0292] In this design, the DU receives the sixth status report and determines based on the eleventh indication that the current status report is an “order” status report. Specifically, the status report indicates that the DU RLC It can be determined that the status report is a combination of status reports of terminal devices that deliver the first PDCP PDU in order by using AM, or that it is an "out-of-order" status report, specifically, that the status report is a combination of status reports of terminal devices that deliver the first PDCP PDU out of order by using RLC by the DU.

[0293] Design b: The sixth status report carries thirteenth indication information, which indicates whether the sixth status report includes status reports of all terminal devices included in the first terminal device, in other words, whether the sixth status report is a combination of the status reports of all terminal devices included in the first terminal device, and / or the seventh status report carries thirteenth indication information, which indicates whether the seventh status report includes status reports of all terminal devices included in the first terminal device, in other words, whether the seventh status report is a combination of the status reports of all terminal devices included in the first terminal device.

[0294] For example, the sixth status report is used as an example. The thirteenth indication information may take the form of adding a "complete" field. If the field is "0", it indicates that the status report is incomplete, specifically, that the sixth status report is not a combination of the status reports of all the terminal devices included in the first terminal device. If the field is "1", it indicates that the status report is complete, specifically, that the sixth status report is a combination of the status reports of all the terminal devices included in the first terminal device.

[0295] Optionally, the CU may determine only the type of the status report, specifically, whether the status report is an "ordered" status report or an "unordered" status report, based on the above design a. However, the CU cannot determine whether the status report is a combination of the status reports of all terminal devices included in the first terminal device. Therefore, the CU may refer to designs a and b to determine whether the received status report is complete.

[0296] For example, if the CU first receives the sixth status report and determines based on the eleventh indication information that the status report is an “order” status report, and determines based on the thirteenth indication information that the status report is incomplete, specifically, that the status report is not a status report for all terminal devices among the first terminal devices that use RLC AL, the CU may determine that it needs to wait for further “out-of-order” status reports.

[0297] For example, if the CU first receives the seventh status report and determines based on the twelfth indication information that the status report is an "out of order" status report, and based on the thirteenth indication information that the status report is complete, the CU may determine that it does not need to wait for the "in order" status report.

[0298] With reference to the above design A and design B, the first status report and the second status report may further include the following design C.

[0299] Design C: The first status report carries third indication information, and the third indication information indicates whether the first status report includes status reports of all terminal devices included in the at least two terminal devices, in other words, whether the first status report is a combination of status reports of all terminal devices included in the at least two terminal devices; and / or The second status report carries third indication information, and the third indication information indicates whether the second status report includes status reports of all terminal devices included in the at least two terminal devices, in other words, whether the second status report is a combination of status reports of all terminal devices included in the at least two terminal devices.

[0300] Similarly, the third indication information may alternatively be implemented in the above manner of the thirteenth indication information, and the details will not be described again here.

[0301] For example, in this design, referring to Design A above, when the DU, or the DU and CU together, determine to transmit a first PDCP PDU to a first terminal device in PTM mode and a first PDCP PDU to a second terminal device in PTP mode, if the CU first receives a first status report, the CU may only determine, based on the first indication information, that the first status report is a combination of the status reports of the first terminal device. The CU cannot determine whether the second device is still present, in other words, whether the CU needs to wait for a second status report. In this case, referring to Design C, the CU may determine, based on the third indication information, whether the first status report is complete, specifically, whether the first status report is a combination of the status reports of all terminal devices. If the first status report is complete, the CU may determine that the CU does not need to continue waiting for a second status report. If the first status report is incomplete, the CU may determine that the CU needs to wait for a second status report.

[0302] For example, in this design, referring to Design B above, if the DU, or the DU and CU together, decide to transmit a first PDCP PDU to a first terminal device using RLC AM and to a second terminal device using RLC UM, if the CU first receives the first status report, the CU cannot determine whether the second terminal device is still present; in other words, the CU cannot determine whether it needs to wait for a second status report. In this case, referring to Design C, the CU may determine whether the first status report is complete, specifically, whether the first status report is a combination of status reports from all terminal devices, based on the third indication information. If the first status report is complete, the CU may determine that it does not need to continue waiting for a second status report. If the first status report is incomplete, the CU may determine that it needs to wait for a second status report.

[0303] For example, in this design, regardless of whether the CU, or the DU, or the CU and the DU together determine the mode in which to transmit the first PDCP PDU to the first terminal device and the second terminal device, assuming that the CU first receives the first status report, the CU may determine whether the first status report is complete based only on the third indication information. If the third indication information indicates that the first status report is complete, the CU determines that the CU does not need to continue waiting for another status report, and if the third indication information indicates that the first status report is incomplete, the CU determines that the CU needs to continue waiting for another status report.

[0304] Optionally, in design 1 above, the status report may include design D below.

[0305] Design D: The status report carries fourth indication information, and the fourth indication information indicates that the status report corresponds to RLC UM. Note that "the status report corresponds to RLC UM" means that the status report is an "RLC UM" status report, and specifically, the status report is a combination of status reports of terminal devices in which the CU transmits the first PDCP PDU by using RLC UM.

[0306] Optionally, the fourth instruction information may alternatively use the implementation of the tenth instruction information, the details of which will not be described again here.

[0307] For example, in this design, when the CU determines to send a first PDCP PDU to at least two terminal devices by using RLC UM, assuming that the CU receives a status report, the CU can determine, based only on the fourth indication information, that the status report is complete, in other words, the status report is a combination of the status reports of all the terminal devices, and the CU can determine that the CU does not need to continue waiting for another status report.

[0308] If the CU receives a status report when the DU, or the DU and CU together, determine to transmit the first PDCP PDU to at least two terminal devices by using RLC UM, the CU cannot determine whether the status report is complete based only on the fourth indication information. In this case, if a third terminal device exists and the third terminal device is at least one terminal device other than the at least two terminal devices, in other words, if the DU transmits the first PDCP PDU to the third terminal device and at least two terminal devices, the status report should further carry a "complete" indication, specifically, whether the status report is a combination of the status reports of all terminal devices to which the DU transmits the first PDCP PDU. If the indication indicates that the status report is complete, the CU determines that it does not need to continue waiting for another status report. If the indication indicates that the status report is incomplete, the CU determines that it needs to continue waiting for another status report.

[0309] Optionally, the "complete" indication may alternatively be implemented in the manner described above in the thirteenth indication information, the details of which will not be described again here.

[0310] For example, in this design, regardless of whether the CU, or the DU, or the CU and DU together determine the mode in which to transmit the first PDCP PDU to the first and second terminal devices, assuming the CU receives a status report, the CU may determine whether the status report is complete based solely on the “complete” indication carried in the status report. If the indication indicates that the status report is complete, the CU may determine that the CU does not need to continue waiting for another status report, and if the indication indicates that the status report is incomplete, the CU may determine that the CU needs to continue waiting for another status report.

[0311] Optionally, in Design 2 above, the status report may include Design E below.

[0312] Design E: The status report carries first indication information, and the first indication information indicates that the status report corresponds to the PTM mode. "The status report corresponds to the PTM mode" means that the status report is a "PTM" status report, specifically, the status report is a combination of status reports of terminal devices whose DUs transmit first PDCP PDUs in the PTM mode.

[0313] For example, in this design, when the CU determines to send the first PDCP PDU to at least two terminal devices in PTM mode, assuming that the CU receives a status report, the CU can determine, based only on the first indication information, that the status report is complete, in other words, the status report is a combination of the status reports of all the terminal devices, and the CU can determine that the CU does not need to continue waiting for other status reports.

[0314] Otherwise it is the same as design D above and the details will not be described again here.

[0315] Optionally, the status report, the first status report, and the second status report may further carry any one or more of the following information (1) to (5):

[0316] (1) Fifth indication information: The fifth indication information indicates the desired buffer size of the radio bearer RB associated with the MBS.

[0317] Optionally, the CU may determine a desired buffer size of a radio bearer RB associated with the MBS based on the fifth indication information. The operations performed by the CU may be performed by the processor 401 of the communication device 400 by invoking an application program stored in the memory 403, or may be performed by the processing module 501 of the communication device 500.

[0318] In a possible implementation, the fifth indication information may be implemented by adding an "MBS" indication to the "Desired Buffer Size for Data Radio Bearer" field in the frame structure shown in Table 2.

[0319] In another possible implementation, the fifth indication information may directly change the "Desired Buffer Size of Data Radio Bearer" field in the frame structure shown in Table 2 to the "Desired Buffer Size of MBS Radio Bearer" field, or may change the "Desired Buffer Size of Data Radio Bearer" field to the "Related MBS This may be implemented by modifying the "Desired Buffer Size" field in the

[0320] In yet another possible implementation, the fifth indication information is a "Desired Buffer Size of MBS Radio Bearer" field or a "Related MBS Alternatively, the method may be implemented by adding a "Desired Buffer Size" field separately.

[0321] The implementation of the fifth instruction information is not limited in this application.

[0322] (2) Sixth instruction information: The sixth instruction information indicates a desired data rate.

[0323] Optionally, the CU may determine the desired data rate based on the sixth indication information. The operations performed by the CU may be performed by the processor 401 of the communication device 400 by invoking an application program stored in the memory 403, or may be performed by the processing module 501 of the communication device 500.

[0324] For example, the sixth indication information may be implemented as a "Desired Data Rate" field shown in Table 2. Alternatively, the sixth indication information may be implemented in other ways, which is not limited in this application.

[0325] For example, in an example in which a CU determines a desired data rate when it receives multiple status reports, e.g., when it receives a first status report and a second status report, if both the first status report and the second status report carry sixth indication information, the CU may determine the desired data rate based on the sixth indication information of the first-received status report. For example, assuming that the CU receives the first status report first, the CU may determine the desired data rate based on the sixth indication information of the first status report, and assuming that the CU receives the second status report first, the CU may determine the desired data rate based on the sixth indication information of the second status report.

[0326] For example, when the CU receives multiple status reports, for example, if the multiple status reports include the above-mentioned "DDDS Report for Single UE" status report and also include a status report provided in the embodiment of the present application ("DDDS Report for Multiple UEs" status report), the CU may choose to determine the desired data rate based on the sixth indication information carried in the status report provided in the embodiment of the present application. Alternatively, the CU may further determine the desired data rate based on the related indication information in the "DDDS Report for Single UE" status report.

[0327] Optionally, the manner in which the CU determines the desired buffer size of the radio bearer RB associated with the MBS may be similar to the manner in which the CU determines the desired data rate, and the details will not be described again here.

[0328] (3) Seventh Indication Information: The seventh indication information indicates the highest sequence number SN of at least one PDCP PDU that has been successfully transmitted among the first PDCP PDUs.

[0329] For example, the seventh indication information may be specifically implemented as a "Highest Successfully Delivered NR PDCP Sequence Number" field, a "Highest Transmitted NR PDCP Sequence Number" field, a "Highest NR PDCP PDCP PDU Sequence Number Successfully Delivered in Order to the UE" field, etc. in the frame structure shown in Table 2.

[0330] (4) Eighth instruction information: The eighth instruction information indicates the number and start SN of at least one PDCP PDU that has been successfully transmitted by a DU among the first PDCP PDUs; alternatively, the eighth instruction information indicates the number and end SN of at least one PDCP PDU that has been successfully transmitted by a DU among the first PDCP PDUs; alternatively, the eighth instruction information indicates the start SN and end SN of at least one PDCP PDU that has been successfully transmitted by a DU among the first PDCP PDUs; alternatively, the eighth instruction information indicates the number, start SN, and end SN of at least one PDCP PDU that has been successfully transmitted by a DU among the first PDCP PDUs.

[0331] For example, the eighth indication information may be specifically implemented in any combination of three fields, namely, the "Number of successfully delivered unordered PDCP sequence number ranges" field, the "Start of successfully delivered unordered PDCP sequence number range" field, and the "End of successfully delivered unordered PDCP sequence number range" field in the frame structure shown in Table 2.

[0332] (5) Bitmap: The bitmap indicates the results of transmitting the first PDCP PDU to at least two terminal devices.

[0333] For example, the bitmap may be implemented by newly defining an index in the frame structure shown in Table 2. If the index is "0", in other words, if the index is not present, the status report does not carry the associated field of the bitmap. If the index is "1", the status report may carry the associated field of the bitmap. The specific implementation of the bitmap is not limited by this application.

[0334] For example, the bitmap may be shown in Figure 8, and the transmission result is [1,1,0,0,0,1,1,0]. It is assumed that the first PDCP PDU includes eight PDCP PDUs from SN1 to SN8. For example, the at least two terminal devices include three terminal devices, namely, UE1 to UE3. SN1, SN4, SN6, and SN8 are transmitted by the DU to UE1, UE2, and UE3 in PTP mode. SN2, SN3, SN5, and SN7 are transmitted by the DU to UE1, UE2, and UE3 in PTM mode. SN1 is successfully transmitted to UE1, UE2, and UE3, and "1" indicates that SN1 is successfully transmitted. 。S SN2, SN6, and SN7 successfully transmitted to UE1, UE2, and UE3, respectively, with a "1" indicating successful transmission of the PDCP PDU. SN3 failed to transmit to the three UEs, with a "0" indicating that SN3 failed to transmit. Similarly, a "0" indicates that SN4, SN5, and SN8 also failed to transmit.

[0335] MBS For PDCP PDUs carried in the PTP mode, different PDCP PDUs may correspond to the PTP mode and the PTM mode separately. Therefore, feeding back the PDCP PDU transmission status based on the bitmap can avoid the problem that when the highest SN indicated in the status report corresponding to the PTP mode and the highest SN indicated in the status report corresponding to the PTM mode are not the same, the CU cannot determine which highest SN should be used and it is difficult to determine.

[0336] Optionally, the CU may determine the highest SN of at least one of the first PDCP PDUs that has been successfully transmitted based on the seventh indication, the eighth indication, or the bitmap. The operations performed by the CU may be performed by the processor 401 of the communication device 400 by invoking an application program stored in the memory 403, or may be performed by the processing module 501 of the communication device 500.

[0337] For example, when a DU receives multiple status reports, e.g., when the DU receives a first status report and a second status report, both the first status report and the second status report carry seventh indication information, the seventh indication information carried in the first status report indicates that the highest SN of at least one PDCP PDU successfully transmitted by the DU is 8, and the seventh indication information carried in the second status report indicates that the highest SN of at least one PDCP PDU successfully transmitted by the DU is 5, the DU may select the highest SN of both highest SNs; in other words, the CU determines "8" as the highest SN of at least one PDCP PDU successfully transmitted among the first PDCP PDUs.

[0338] Optionally, the method shown in FIG. 7 may further include the following steps (not shown):

[0339] S704: The DU sends a third status report to the CU, and the CU correspondingly receives the third status report sent by the DU, where: In step S704, the operations performed by the CU may be performed by the communication interface 404 of the communication device 400 and the communication module 502 of the communication device 500, or the operations performed by the DU may be performed by the communication interface 404 of the communication device 400 and the communication module 502 of the communication device 500; The third status report is a status report dedicated to feeding back the desired buffer size of the RB associated with the MBS; and / or

[0340] S705: The DU sends a fourth status report to the CU, and the CU receives the fourth status report sent by the DU accordingly, where: In step S705, the operations performed by the CU may be performed by the communication interface 404 of the communication device 400 and the communication module 502 of the communication device 500, or the operations performed by the DU may be performed by the communication interface 404 of the communication device 400 and the communication module 502 of the communication device 500; the fourth status report is a status report dedicated to feedback of the desired data rate; and / or

[0341] S706: The DU sends a fifth status report to the CU, and in response, the CU receives the fifth status report sent by the DU.

[0342] The fifth status report is a status report dedicated to feeding back the desired buffer size and desired data rate of the RB associated with the MBS.

[0343] In step S706, the operations performed by the CU may be performed by the communication interface 404 of the communication device 400 and the communication module 502 of the communication device 500. Alternatively, the operations performed by the DU may be performed by the communication interface 404 of the communication device 400 and the communication module 502 of the communication device 500.

[0344] Optionally, the CU may determine a status report of a desired buffer size of the RB associated with the MBS based on the third status report, may determine a desired data rate based on the fourth status report, or may determine a desired buffer size and a desired data rate of the RB associated with the MBS based on the fifth status report. Optionally, the status report, the first status report, and the second status report may further carry other information, such as related information indicating a packet loss status, such as "reported number of lost NR-U sequence number ranges," "start of lost NR-U sequence number range," and "end of lost NR-U sequence number range" in the frame structure shown in Table 2. The CU may further determine a packet loss status of the first PDCP PDU based on the information.

[0345] Optionally, the embodiments of the present application further provide a computer-readable storage medium, which stores computer instructions, and when the computer instructions are executed by a computer, the computer can perform the methods described in the above embodiments.

[0346] Optionally, the embodiments of the present application further provide a computer program product carrying computer instructions, which, when executed by a computer, enable the computer to perform the methods described in the above embodiments.

[0347] Optionally, the present embodiment further provides a chip including a processing circuit and a transceiver pin, the processing circuit and the transceiver pin being configured to implement the method described in the above embodiment, the processing circuit being configured to perform the processing operations of the corresponding method, and the transceiver pin being configured to perform the receive / transmit operations of the corresponding method.

[0348] Those skilled in the art will understand that all or part of the above embodiments can be implemented by software, hardware, firmware, or any combination thereof. When software is used to implement the embodiments, all or part of the embodiments can be implemented in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the procedures or functions of the embodiments of the present application are generated in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions may be stored in a computer-readable storage medium or transmitted from a computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions may be transmitted from a website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, optical fiber, or Digital Subscriber Line (DSL)) or wireless (e.g., infrared, radio wave, or microwave) transmission. The computer-readable storage medium may be any available medium accessible by a computer or a data storage device, such as a server or data center, incorporating one or more available media. The usable media may be magnetic media (e.g., floppy disks, hard disks, or magnetic tapes), optical media (e.g., Digital Versatile Disks (Digital Video Discs, DVDs)), semiconductor media (e.g., Solid-State Drives (SSDs)), and the like.

[0349] It should be understood that in some embodiments provided herein, the disclosed systems, devices, and methods may be implemented in other ways. For example, the described device embodiments are merely examples. For example, the division into modules is merely a logical division of function, and other divisions may be used in actual implementation. For example, multiple modules or components may be combined or integrated into other systems, or some features may be omitted or not implemented. Furthermore, any mutual couplings or direct couplings or communication connections shown or discussed may be implemented through some interface. Indirect couplings or communication connections between devices or modules may be implemented in electrical or other forms.

[0350] The units described as separate blocks may or may not be physically separated, and the parts shown as units may or may not be physical units, i.e., they may be located in one place or distributed across multiple devices. Some or all of the units may be selected based on actual requirements to achieve the objectives of the solutions of the embodiments.

[0351] Based on the above description of implementation, those skilled in the art can clearly understand that the present application can be implemented by software in addition to required general-purpose hardware, or by hardware alone. In most situations, the former is a preferred implementation. Based on such understanding, the technical solutions of the present application can be essentially or in part implemented in the form of a software product. A computer software product is stored in a computer-readable storage medium, such as a floppy disk, a hard disk, or an optical disk, and includes some instructions that instruct a computer device (which may be a personal computer, a server, a network device, etc.) to perform the methods described in the embodiments of the present application.

[0352] The above description is merely a specific implementation of the present application and is not intended to limit the scope of protection of the present application. Any modifications or replacements within the technical scope disclosed in the present application should fall within the scope of protection of the present application. Therefore, the scope of protection of the present application should be subject to the scope of protection of the claims.

[0353] This application claims priority to Chinese Patent Application No. 202110487916.4, filed with the State Intellectual Property Office of the People's Republic of China on April 30, 2021, for the invention titled "DATA TRANSMISSION METHOD AND APPARATUS," and the prior Chinese patent application is incorporated herein by reference in its entirety.

Claims

1. 1. A data transmission method, comprising: receiving, by a distribution unit (DU), a first Packet Data Convergence Protocol (PDCP) Packet Data Unit (PDU) from a central unit (CU), the first PDCP PDU carrying Multicast Broadcast Service (MBS) data; transmitting the first PDCP PDU to at least two terminal devices via the PDCP PDU; transmitting, by the DU, a status report to the CU indicating a result of the transmission of the first PDCP PDU by the DU to the at least two terminal devices; and the status report is obtained by the DU by combining results of transmitting the first PDCP PDU to the at least two terminal devices; the status report is a downlink data delivery status, and the downlink data delivery status includes a first field, the first field indicating a highest sequence number (SN) of all the first PDCP PDUs that the DU has successfully transmitted to the at least two terminal devices; method.

2. transmitting the first PDCP PDU to at least two terminal devices by the PDCP PDU; transmitting the first PDCP PDU to the at least two terminal devices by using a Radio Link Control (RLC) Unacknowledged Mode (UM) with the DU. The method of claim 1.

3. transmitting the first PDCP PDU to at least two terminal devices by the PDCP PDU; transmitting the first PDCP PDU to the at least two terminal devices in a point-to-multipoint (PTM) mode using the DU. The method of claim 1.

4. transmitting the first PDCP PDU to at least two terminal devices by the PDCP PDU; transmitting, by the PDCP PDU, the first PDCP PDU to a first terminal device of the at least two terminal devices by using an RLC acknowledged mode (AM), the first terminal device including at least one terminal device; and transmitting, via the DU, the first PDCP PDU to a second terminal device of the at least two terminal devices by using an RLC UM, the second terminal device including at least one terminal device; the status report indicating a result of the transmission of the first PDCP PDU to the first terminal device and a result of the transmission of the first PDCP PDU to the second terminal device. The method of claim 1.

5. Sending a status report by the DU to the CU includes: transmitting, by the DU, a first status report to the CU indicating a result of transmission of the first PDCP PDU to the first terminal device; and transmitting, by the DU, a second status report to the CU indicating a result of the transmission of the first PDCP PDU to the second terminal device. The method of claim 4.

6. the first status report carries first indication information, the first indication information indicating that the first status report corresponds to the RLC AM; the second status report carries second indication information, and the second indication information indicates that the second status report corresponds to the RLC UM. The method of claim 5.

7. the first status report carries third indication information, the third indication information indicating whether the first status report includes status reports of all terminal devices included in the at least two terminal devices; and / or the second status report carries third indication information, and the third indication information indicates whether the second status report includes status reports of all terminal devices included in the at least two terminal devices; 7. The method according to claim 5 or 6.

8. the status report carries fourth indication information, and the fourth indication information indicates that the status report corresponds to the RLC UM. The method of claim 2.

9. the status report carries first indication information, the first indication information indicating that the status report corresponds to the PTM mode. The method of claim 3.

10. the status report carries a fifth indication, the fifth indication indicating a desired buffer size of a radio bearer RB associated with the MBS; and / or the status report carries sixth indication information, the sixth indication information indicating a desired data rate.

10. The method according to any one of claims 5 to 9.

11. the first PDCP PDU includes one or more PDCP PDUs, and the status report carries seventh indication information, the seventh indication information indicating a highest sequence number (SN) of at least one PDCP PDU among the first PDCP PDUs that has been successfully transmitted by the PDCP PDU; 11. The method according to any one of claims 5 to 10.

12. 1. A data transmission method, comprising: transmitting, by the CU, a first PDCP PDU carrying data of the MBS to the DU; receiving, by the CU, from the DU a status report indicating a result of the transmission of the first PDCP PDU by the DU to at least two terminal devices; and the status report is obtained by the DU by combining results of transmitting the first PDCP PDU to the at least two terminal devices; the status report is a downlink data delivery status, and the downlink data delivery status includes a first field, and the first field indicates a highest SN of all the first PDCP PDUs that the DU has successfully transmitted to the at least two terminal devices. method.

13. Receiving a status report from the DU by the CU includes: receiving, by the CU, from the DU, a first status report indicating a result of transmission of the first PDCP PDU to a first terminal device of the at least two terminal devices, the first terminal device including at least one terminal device; receiving, by the CU, from the DU, a second status report indicating a result of transmission of the first PDCP PDU to a second terminal device of the at least two terminal devices, the second terminal device including at least one terminal device. The method of claim 12.

14. the first status report carries first indication information, the first indication information indicating that the first status report corresponds to a PTM mode; the second status report carries second indication information, and the second indication information indicates that the second status report corresponds to a PTP mode. The method of claim 13.

15. the first status report carries third indication information, the third indication information indicating whether the first status report includes status reports of all terminal devices included in the at least two terminal devices; and / or the second status report carries third indication information, and the third indication information indicates whether the second status report includes status reports of all terminal devices included in the at least two terminal devices; 15. The method of claim 13 or 14.

16. the status report carries fourth indication information, and the fourth indication information indicates that the status report corresponds to RLC UM.

16. The method according to any one of claims 12 to 15.

17. the status report carries first indication information, and the first indication information indicates that the status report corresponds to a PTM mode.

14. The method according to claim 12 or 13.

18. the status report carries a fifth indication, the fifth indication indicating a desired buffer size of a RB associated with the MBS; and / or the status report carries sixth indication information, the sixth indication information indicating a desired data rate.

18. The method according to any one of claims 13 to 17.

19. the first PDCP PDU includes one or more PDCP PDUs, and the status report carries seventh indication information, the seventh indication information indicating a highest SN of at least one PDCP PDU among the first PDCP PDUs that has been successfully transmitted; 19. The method of any one of claims 13 to 18.

20. The method comprises: determining, by the CU, the desired buffer size of the RB associated with the MBS based on the fifth indication information carried in the status report, and / or determining, by the CU, the desired data rate based on the sixth indication information carried in the status report; determining, by the CU, the desired buffer size of the RB associated with the MBS based on a third status report, and / or determining the desired data rate based on a fourth status report; or determining, by the CU, the desired buffer size and / or the desired data rate of the RB associated with the MBS based on a fifth status report; Further comprising:

20. The method of claim 18.

21. The method comprises: determining, by the CU, the highest SN of the at least one PDCP PDU among the first PDCP PDUs whose DUs have been successfully transmitted based on the seventh indication carried in the status report; determining, by the CU, based on eighth indication information carried in the status report, the highest SN of the at least one PDCP PDU among the first PDCP PDUs whose DU has been successfully transmitted; or determining, by the CU, the highest SN of the at least one PDCP PDU among the first PDCP PDUs for which the DU was successfully transmitted based on a bitmap carried in the status report; Further comprising:

20. The method of claim 19.

22. A communication device having a communication module, The communication module is configured to receive a first PDCP PDU from a CU, the first PDCP PDU carrying data of an MBS; the communication module is configured to transmit the first PDCP PDU to at least two terminal devices; the communication module is configured to send a status report to the CU, the status report indicating a result of the transmission of the first PDCP PDU by the communication apparatus to the at least two terminal devices; the status report is obtained by the communication device by combining results of transmitting the first PDCP PDU to the at least two terminal devices; the status report is a downlink data delivery status, and the downlink data delivery status includes a first field, the first field indicating a highest sequence number (SN) of all the first PDCP PDUs that the communication device has successfully transmitted to the at least two terminal devices; Communication equipment.

23. the communication module is further configured to transmit the first PDCP PDU to the at least two terminal devices by using RLC UM.

23. The communication device of claim 22.

24. the communication module is further configured to transmit the first PDCP PDU to the at least two terminal devices in a PTM mode.

23. The communication device of claim 22.

25. the communication module is further configured to transmit the first PDCP PDU to a first terminal device of the at least two terminal devices by using RLC AM, the first terminal device including at least one terminal device; the communication module is further configured to transmit the first PDCP PDU to a second terminal device of the at least two terminal devices by using RLC UM, the second terminal device including at least one terminal device; the status report indicating a result of the transmission of the first PDCP PDU to the first terminal device and a result of the transmission of the first PDCP PDU to the second terminal device.

23. The communication device of claim 22.

26. the communication module is further configured to send a first status report to the CU indicating a result of transmitting the first PDCP PDU to the first terminal device; the communication module is further configured to send a second status report to the CU indicating a result of the transmission of the first PDCP PDU to the second terminal device.

26. The communication device of claim 25.

27. the first status report carries first indication information, the first indication information indicating that the first status report corresponds to the RLC AM; the second status report carries second indication information, and the second indication information indicates that the second status report corresponds to the RLC UM.

27. The communication device of claim 26.

28. the first status report carries third indication information, the third indication information indicating whether the first status report includes status reports of all terminal devices included in the at least two terminal devices; and / or the second status report carries third indication information, and the third indication information indicates whether the second status report includes status reports of all terminal devices included in the at least two terminal devices; 28. A communication device according to claim 26 or 27.

29. the status report carries fourth indication information, and the fourth indication information indicates that the status report corresponds to the RLC UM.

24. The communication device of claim 23.

30. the status report carries first indication information, the first indication information indicating that the status report corresponds to the PTM mode.

25. The communication device of claim 24.

31. the status report carries a fifth indication, the fifth indication indicating a desired buffer size of a radio bearer RB associated with the MBS; and / or the status report carries sixth indication information, the sixth indication information indicating a desired data rate.

31. A communication device according to any one of claims 26 to 30.

32. the first PDCP PDU includes one or more PDCP PDUs, and the status report carries seventh indication information, the seventh indication information indicating a highest sequence number (SN) of at least one PDCP PDU successfully transmitted by the communication device among the first PDCP PDUs; 32. A communication device according to any one of claims 26 to 31.

33. A communication device having a communication module, The communication module is configured to transmit a first PDCP PDU to a DU, the first PDCP PDU carrying data of an MBS; The communication module is further configured to receive a status report from the DU, the status report indicating a result of the transmission of the first PDCP PDU by the DU to at least two terminal devices; the status report is obtained by the DU by combining results of transmitting the first PDCP PDU to the at least two terminal devices; the status report is a downlink data delivery status, and the downlink data delivery status includes a first field, the first field indicating a highest sequence number (SN) of all the first PDCP PDUs that the DU has successfully transmitted to the at least two terminal devices; Communication equipment.

34. the communication module is further configured to receive from the PDCP PDU a first status report indicating a result of transmission of the first PDCP PDU to a first terminal device of the at least two terminal devices, the first terminal device including at least one terminal device; the communication module is further configured to receive from the PDCP PDU a second status report indicating a result of transmission of the first PDCP PDU to a second terminal device of the at least two terminal devices, the second terminal device including at least one terminal device.

34. The communication device of claim 33.

35. the first status report carries first indication information, the first indication information indicating that the first status report corresponds to a PTM mode; the second status report carries second indication information, and the second indication information indicates that the second status report corresponds to a PTP mode.

35. The communication device of claim 34.

36. the first status report carries third indication information, the third indication information indicating whether the first status report includes status reports of all terminal devices included in the at least two terminal devices; and / or the second status report carries third indication information, and the third indication information indicates whether the second status report includes status reports of all terminal devices included in the at least two terminal devices; 36. A communication device according to claim 34 or 35.

37. the status report carries fourth indication information, and the fourth indication information indicates that the status report corresponds to RLC UM.

37. A communication device according to any one of claims 33 to 36.

38. the status report carries first indication information, and the first indication information indicates that the status report corresponds to a PTM mode.

35. A communication device according to claim 33 or 34.

39. the status report carries a fifth indication, the fifth indication indicating a desired buffer size of a RB associated with the MBS; and / or the status report carries sixth indication information, the sixth indication information indicating a desired data rate.

39. A communication device according to any one of claims 34 to 38.

40. the first PDCP PDU includes one or more PDCP PDUs, and the status report carries seventh indication information, the seventh indication information indicating a highest SN of at least one PDCP PDU among the first PDCP PDUs that has been successfully transmitted; 40. A communication device according to any one of claims 34 to 39.

41. further comprising a processing module; the processing module is configured to determine the desired buffer size of the RB associated with the MBS based on the fifth indication carried in the status report, and / or to determine the desired data rate based on the sixth indication carried in the status report; the processing module is configured to determine the desired buffer size for the RB associated with the MBS based on a third status report and / or to determine the desired data rate based on a fourth status report; or the processing module is configured to determine the desired buffer size and / or the desired data rate of the RB associated with the MBS based on a fifth status report.

40. The communication device of claim 39.

42. further comprising a processing module; the processing module is configured to determine, based on the seventh indication carried in the status report, the highest SN of the at least one PDCP PDU among the first PDCP PDUs whose PDCP PDUs have been successfully transmitted; the processing module is configured to determine, based on eighth indication information carried in the status report, the highest SN of the at least one PDCP PDU among the first PDCP PDUs for which the PDCP PDU was successfully transmitted; or the processing module is configured to determine, based on a bitmap carried in the status report, the highest SN of the at least one PDCP PDU among the first PDCP PDUs for which the PDCP PDU was successfully transmitted.

41. The communication device of claim 40.

43. 1. A computer-readable storage medium having computer instructions, comprising: The computer instructions, when executed on a computer, enable the computer to carry out the method of any one of claims 1 to 11. A computer-readable storage medium.

44. A computer program comprising: The computer program, when executed on a computer, enables the computer to carry out the method according to any one of claims 1 to 11. Computer program.

45. A chip having a processor, When the processor executes the instructions, the processor is capable of performing the method of any one of claims 1 to 11. Tips.

46. 1. A computer-readable storage medium having computer instructions, comprising: The computer instructions, when executed on a computer, enable the computer to carry out the method of any one of claims 12 to 21. A computer-readable storage medium.

47. A computer program comprising: The computer program, when executed on a computer, enables the computer to carry out the method according to any one of claims 12 to 21. Computer program.

48. A chip having a processor, When the processor executes the instructions, the processor is capable of performing the method of any one of claims 12 to 21. Tips.

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