Communication method and communication device

Abstract

The embodiment of the invention provides a communication method and a communication device. Transmission of a first PDU (Protocol Data Unit) Set in a cascade scene can be realized. The method comprises: an access network device receiving first indication information from a session management function network element, the first indication information being used for indicating the access network device to add first information in a first protocol data unit set PDU Set; the access network equipment receives one or more data packets of a first PDU Set from a user plane function network element; the access network device sends one or more data packets of the first PDU Set to the first terminal device, at least one of the one or more data packets of the first PDU Set sent to the first terminal device carries first information, and the first information is used for sending the first PDU Set to the second terminal device when the first terminal device sends the first PDU Set to the second terminal device. And processing the data packet of the first PDU Set according to the first information.

Description

Technical Field

[0001] This application relates to the field of communications, and more particularly, to a communication method and a communication device. Background Art

[0002] Currently, for real-time media services, such as the currently emerging virtual reality (VR) / artificial reality (AR) / mixed reality (MR) and cloud gaming services, there are extremely stringent requirements for end-to-end latency, and the data processing granularity corresponding to the upper-layer media services during encoding and transmission is no longer based on the granularity of data packets. For example, during encoding in the media layer, processing is often performed at the granularity of media frames or slices, that is, media frames, slices, etc. can be independently encoded; at the same time, the receiving side also performs decoding and display processing at the corresponding granularity of media frames or slices. Basic data units such as media frames or slices often contain multiple data packets. Standardly, the basic data unit of the above-mentioned media service layer is called a protocol data unit set (PDU Set), and the PDU Set is the basic data unit that the upper-layer service layer can independently process.

[0003] However, in current technical solutions, the scenario of multiple nodes collaborating to implement PDU Set processing has not been considered. For example, in a cascaded scenario, that is, a scenario where a second terminal device is connected under a first terminal device, there is currently no solution for joint processing in the relevant PDU Set cascaded scenario. Summary of the Invention

[0004] Embodiments of this application provide a communication method and a communication device, which can enable the transmission of the first PDU Set in a cascaded scenario or a handover scenario.

[0005] To achieve the above objective, this application adopts the following technical solutions:

[0006] In a first aspect, a communication method is provided. This method can be executed by an access network device, or by components of the access network device, such as a processor, a chip, or a chip system of the access network device, or can also be implemented by a logic module or software that can implement all or part of the functions of the access network device. Taking the case where this method can be executed by an access network device as an example, the method includes: The access network device receives first indication information from a session management function network element, where the first indication information is used to instruct the access network device to add first information to a first protocol data unit set (PDU Set); The access network device receives one or more data packets of the first PDU Set from a user plane function network element; The access network device sends one or more data packets of the first PDU Set to a first terminal device, where at least one of the one or more data packets of the first PDU Set sent to the first terminal device carries the first information, and the first information is used for the first terminal device to process the data packets of the first PDU Set according to the first information when sending the first PDU Set to a second terminal device.

[0007] In the communication method provided by the embodiments of this application, the access network device adds the first information to at least one of the one or more data packets of the first PDU Set sent to the first terminal device according to the first indication information received from the session management function network element, which instructs the access network device to add the first information to the first PDU Set, so that the first terminal device can process the data packets of the first PDU Set according to the first information carried in at least one of the one or more data packets of the first PDU Set received from the access network device. This solution enables the intermediate transmission node in the cascaded scenario, that is, the first terminal device, to process the first PDU Set received from the access network device, thereby enabling the transmission of the first PDU Set in the cascaded scenario. For example, the first terminal device determines whether one or more data packets received from the access network device belong to the first PDU Set of the first terminal device according to the first information; or for example, the first terminal device determines whether to send the data packets of the first PDU Set to the second terminal device according to the first information.

[0008] Combined with the above first aspect, the communication method provided by the embodiments of the present application further includes: The access network device determines first information according to the transmission status of the data packets of the first PDU Set sent to the first terminal device. This solution enables the access network device to determine the first information for the first terminal device to send the first PDU Set to the second terminal device according to the transmission status of the data packets of the first PDU Set sent to the first terminal device, making the subsequent transmission of the data packets of the first PDU Set more accurate. For example, the access network device determines the updated first delay carried in the data packets of the first PDU Set subsequently sent to the first terminal device according to the delay of the data packets of the first PDU Set that have been sent to the first terminal device, making the updated first delay more accurate, so as to avoid wasting transmission resources caused by sending the data packets of the first PDU Set to the second terminal device according to the unupdated first delay and the second terminal device not having enough time to decode the first PDU Set; Another example is that the access network device determines whether to carry a packet loss indication in the data packets of the first PDU Set subsequently sent to the first terminal device according to the packet loss situation of the data packets of the first PDU Set that have been sent to the first terminal device, avoiding wasting transmission resources caused by still sending the data packets of the first PDU Set to the second terminal device when a packet loss occurs and the first PDU Set cannot be correctly decoded.

[0009] Combined with the above first aspect, in a possible implementation manner, the first information includes at least one of the following: the sequence number information of the first PDU Set, the sequence number information of each data packet in the first PDU Set, or the indication information of the last data packet in the first PDU Set.

[0010] Wherein, when the first information is used for the first terminal device to send the first PDU Set to the second terminal device, processing the data packets of the first PDU Set according to the first information includes: at least one of the sequence number information of the first PDU Set, the sequence number information of each data packet in the first PDU Set, or the indication information of the last data packet in the first PDU Set is used for the first terminal device to determine that one or more data packets received from the access network device belong to the first PDU Set. This solution can enable the first terminal device to send one or more data packets received that belong to the first PDU Set to the second terminal device, thus preparing for the transmission at the PDU Set granularity. Among them, the data packets are transmitted in the form of a PDU Set, which can ensure that encoding and processing can be performed at the PDU Set granularity at the sending end, and decoding and display can be performed at the PDU Set granularity at the receiving end, so as to achieve end-to-end service experience guarantee at the PDU Set granularity.

[0011] Combined with the above first aspect, in a possible implementation manner, the first information includes a first time delay, and the first time delay is used to indicate the transmission time delay budget of the first PDU Set from the first terminal device to the second terminal device, that is, the maximum transmission time delay of the first PDU Set from the first terminal device to the second terminal device. Specifically, the first time delay may be the upper limit of the transmission time delay from the arrival of the first PDU Set at the first terminal device to the last data packet of the first PDU Set being sent to the second terminal device, or the upper limit of the transmission time delay of all data packets of the first PDU Set being sent to the second terminal device. This solution enables the first PDU Set to be sent from the access network device to the second terminal device through the first terminal device, ensuring the transmission time delay threshold of the first PDU Set. At the same time, when one or more data packets of the first PDU Set received by the first terminal device from the access network device meet the first time delay, the first terminal device sends the data packets of the first PDU Set to the second terminal device; if the data packets of the first PDU Set are still sent to the second terminal device when the first time delay is not met, the second terminal device will not have enough time to decode and display the first PDU Set, which will lead to a waste of transmission resources.

[0012] Combined with the above first aspect, in a possible implementation manner, in the embodiments of the present application, the first time delay is determined according to the time when the access network device sends the first data packet of the first PDU Set to the first terminal device and the time delay budget PSDB of the first PDU Set, or the first time delay is determined according to the time when the access network device receives the first PDU Set, the time when the access network device sends the first data packet of the first PDU Set to the first terminal device, and the time delay budget PSDB of the first PDU Set, where the PSDB of the first PDU Set is used to represent the transmission time delay budget of the first PDU Set.

[0013] Combined with the above first aspect, in a possible implementation manner, the communication method provided by the embodiments of the present application further includes: the access network device sends second indication information to the first terminal device, and the second indication information is used to indicate that a packet loss occurs during the process of the access network device sending the data packets of the first PDU Set to the first terminal device, or the number of packet losses. This solution enables the first terminal device to determine not to send the unsent data packets in the first PDU Set to the second terminal device according to the second indication information, avoiding the waste of transmission resources caused by still sending the data packets of the first PDU Set to the second terminal device when a packet loss occurs and the first PDU Set cannot be correctly decoded.

[0014] In a second aspect, a communication method is provided. This method can be executed by a first terminal device, or by components of the first terminal device, such as a processor, a chip, or a chip system of the first terminal device, etc., and can also be implemented by a logic module or software that can implement all or part of the functions of the first terminal device. Taking the case where this method can be executed by the first terminal device as an example, the method includes: The first terminal device receives one or more data packets from an access network device, the one or more data packets belong to a first protocol data unit set PDU Set, and at least one of the one or more data packets carries first information; The first terminal device processes the data packets of the first PDU Set according to the first information.

[0015] In the communication method provided in the embodiments of the present application, the first terminal device receives the first PDU Set from the access network device, and processes the data packets of the first PDU Set according to the first information added to at least one of the one or more data packets of the first PDU Set sent to the first terminal device. This solution enables the intermediate transmission node in the cascading scenario, that is, the first terminal device, to process the received first PDU Set from the access network device, thereby enabling the transmission of the first PDU Set in the cascading scenario. For example, the first terminal device determines whether the one or more data packets received from the access network device belong to the first PDU Set of the first terminal device according to the first information; or for example, the first terminal device determines whether to send the data packets of the first PDU Set to the second terminal device according to the first information.

[0016] Combined with the second aspect above, in a possible implementation manner, in the embodiments of the present application, the first information is determined by the access network device according to the transmission status of the data packets of the first PDU Set sent to the first terminal device. This solution enables the access network device to determine the first information for the first terminal device to send the first PDU Set to the second terminal device according to the transmission status of the data packets of the first PDU Set sent to the first terminal device. That is, the first terminal device will send the first PDU Set to the second terminal device according to the first information, making the subsequent transmission of the data packets of the first PDU Set more accurate. For example, the access network device determines the updated first delay carried in the data packets of the first PDU Set to be sent to the first terminal device subsequently according to the delay of the data packets of the first PDU Set that have been sent to the first terminal device, making the updated first delay more accurate, so as to avoid wasting transmission resources caused by sending the data packets of the first PDU Set to the second terminal device according to the unupdated first delay and the second terminal device not having enough time to decode the first PDU Set. Another example is that the access network device determines whether to carry a packet loss indication in the data packets of the first PDU Set to be sent to the first terminal device subsequently according to the packet loss situation of the data packets of the first PDU Set that have been sent to the first terminal device, avoiding wasting transmission resources caused by still sending the data packets of the first PDU Set to the second terminal device when a packet loss occurs and the first PDU Set cannot be correctly decoded.

[0017] Combined with the second aspect above, in a possible implementation manner, the first information includes at least one of the following: the sequence number information of the first PDU Set, the sequence number information of each data packet in the first PDU Set, or the indication information of the last data packet in the first PDU Set. The first terminal device processes the first PDU Set according to the first information, including: the first terminal device determines that one or more data packets received from the access network device belong to the first PDU Set according to at least one of the sequence number information of the first PDU Set, the sequence number information of each data packet in the first PDU Set, or the indication information of the last data packet in the first PDU Set. This solution can enable the first terminal device to send one or more data packets received that belong to the first PDU Set to the second terminal device, thus preparing for the transmission at the PDU Set granularity. Among them, the data packets are transmitted in the form of a PDU Set, which can ensure that the encoding and processing can be performed at the PDU Set granularity at the sending end, and the decoding and display can be performed at the PDU Set granularity at the receiving end, so as to achieve the end-to-end service experience guarantee at the PDU Set granularity.

[0018] Combined with the above second aspect, in a possible implementation manner, the first information includes a first time delay, and the first time delay is used to indicate the transmission time delay budget of the first PDU Set from the first terminal device to the second terminal device; the first terminal device processes the data packets of the first PDU Set according to the first information, including: when one or more data packets received by the first terminal device from the access network device meet the first time delay, the first terminal device sends the data packets of the first PDU Set to the second terminal device. This solution enables the first terminal device to send the data packets of the first PDU Set to the second terminal device when one or more data packets of the first PDU Set received by the first terminal device from the access network device meet the first time delay, ensuring that the transmission of the first PDU Set can meet the transmission time delay budget; if the data packets of the first PDU Set are still sent to the second terminal device when the first time delay is not met, the second terminal device cannot receive the first PDU Set within the transmission time delay budget, resulting in the transmission of the first PDU Set not meeting the transmission time delay budget requirement, and causing the second terminal device to be unable to decode and display the first PDU Set in a timely manner.

[0019] Combined with the above second aspect, in a possible implementation manner, in the embodiments of the present application, the first time delay is determined according to the time when the access network device sends the first data packet of the first PDU Set to the first terminal device and the time delay budget PSDB of the first PDU Set. The PSDB of the first PDU Set is used to represent the transmission time delay budget of the first PDU Set, that is, the upper limit of the transmission time delay used for the first PDU Set to be received by the access network device and sent to the second terminal device, or the upper limit of the transmission time delay used for the first PDU Set to be received by the core network and sent to the second terminal device.

[0020] Combined with the above second aspect, in a possible implementation manner, the communication method provided in the embodiments of the present application further includes: the first terminal device receives second indication information from the access network device, and the second indication information is used to indicate that packet loss occurs during the process of the access network device sending the data packets of the first PDU Set to the first terminal device, or the number of packets lost; the first terminal device determines not to send the data packets of the first PDU Set to the second terminal device according to the second indication information. This solution can enable the first terminal device to determine not to send the unsent data packets in the first PDU Set to the second terminal device according to the second indication information, avoiding the waste of transmission resources caused by still sending the data packets of the first PDU Set to the second terminal device when the number of lost packets causes the first PDU Set to be unable to be decoded and displayed on the second terminal device side.

[0021] Combined with the second aspect above, in a possible implementation, in the embodiments of the present application, the first terminal device determines not to send the data packets of the first PDU Set to the second terminal device according to the second indication information, including: the first terminal device determines the currently accumulated first packet loss number according to one or more received second indication information, and the first packet loss number includes the number of packet losses that occur during the process of the access network device sending the data packets of the first PDU Set to the first terminal device, and / or the number of packet losses that occur during the process of the first terminal device sending the data packets of the first PDU Set to the second terminal device; in the case where the first packet loss number is greater than the first threshold, the first terminal device determines not to send the data packets of the first PDU Set to the second terminal device. This solution can enable the first terminal device to determine not to send the unsent data packets in the first PDU Set to the second terminal device according to the first packet loss number, and avoid wasting transmission resources caused by still sending the data packets of the first PDU Set to the second terminal device when the number of packet losses causes the first PDU Set to be unable to be decoded and displayed at the second terminal device side.

[0022] In a third aspect, a communication method is provided. This method can be executed by the source access network device, or by components of the source access network device, such as the processor, chip, or chip system of the source access network device, etc., and can also be implemented by a logic module or software that can implement all or part of the functions of the source access network device. Taking the example that this method can be executed by the source access network device, this method includes: the source access network device receives the first protocol data unit set PDU Set; the source access network device sends partial data packets of the first PDU Set to the terminal device; in the case where the terminal device switches to the target access network device, the source access network device sends the unsent data packets in the first PDU Set to the target access network device, where at least one data packet in the unsent data packets in the first PDU Set carries the first information, and the first information is used for the target access network device to process one or more data packets from the source access network device according to the first information when sending one or more data packets from the source access network device to the terminal device.

[0023] In the communication method provided by the embodiment of the present application, the source access network device receives a first PDU Set from the user plane function network element and sends partial data packets of the first PDU Set to the terminal device. When the terminal device switches to the target access network device, the source access network device sends the data packets in the first PDU Set that have not been transmitted to the target access network device, where at least one of the data packets in the data packets in the first PDU Set that have not been transmitted carries first information, and the target access network device processes one or more data packets received from the source access network device according to the first information. This solution ensures the joint transmission of the first PDU Set between the source access network device and the target access network device in the handover scenario. For example, the target access network device determines whether to transmit one or more data packets from the source access network device according to the first information, or the target access network device determines whether one or more data packets received from the source access network device belong to the first PDU Set according to the first information.

[0024] Combined with the above third aspect, the communication method provided by the embodiment of the present application further includes that the source access network device determines the first information according to the transmission status of the data packets of the first PDU Set sent to the terminal device. This solution can enable the target access network device to send one or more data packets from the source access network device to the terminal device more accurately. For example, the source access network device can determine the first redundancy packet ratio or the packet loss indication carried in one or more data packets sent to the target access network device according to the packet loss situation of the data packets that have been transmitted in the data packets of the first PDU Set sent to the terminal device, avoiding the waste of transmission resources caused by still sending one or more data packets from the source access network device to the terminal device when a packet loss occurs and the first PDU Set cannot be correctly decoded.

[0025] In a possible implementation manner combined with the above third aspect, the first information includes at least one of the following: the sequence number information of the first PDU Set, the sequence number information of each data packet in the first PDU Set, or the indication information of the last data packet in the first PDU Set.

[0026] Among them, when the first information is used for the target access network device to send one or more data packets from the source access network device to the terminal device, processing the one or more data packets from the source access network device according to the first information includes: at least one of the sequence number information of the first PDU Set, the sequence number information of each data packet in the first PDU Set, or the indication information of the last data packet in the first PDU Set is used for the target access network device to determine that the one or more data packets received from the source access network device belong to the first PDU Set. This solution can enable the target access network device to send the one or more data packets received and belonging to the first PDU Set to the terminal device, thus preparing for the transmission at the PDU Set granularity. Among them, the data packets are transmitted in the form of PDU Sets, which can ensure that encoding and processing can be performed at the PDU Set granularity at the sending end, and decoding and display can be performed at the PDU Set granularity at the receiving end, so as to realize the end-to-end service experience guarantee at the PDU Set granularity.

[0027] Combined with the above third aspect, in a possible implementation manner, the first information includes a first time delay. The first time delay is used to indicate the transmission time delay budget of the data packets not yet transmitted in the first PDU Set, or the first time delay is used to indicate the transmission time delay budget of the data packets sent from the source access network device to the target access network device in the first PDU Set. Specifically, the first time delay may be the upper limit of the transmission time delay from the target access network device receiving the data packet not yet transmitted to sending it to the terminal device for the data packets not yet transmitted in the first PDU Set. This solution can enable the target access network device to transmit the one or more data packets of the first PDU Set received from the source access network device according to the received first time delay, and ensure that the one or more data packets of the first PDU Set from the source access network device are sent to the terminal device within the first time delay range, ensuring that the transmission of the first PDU Set can meet the requirements of the transmission time delay budget. If the data packets not yet transmitted in the one or more data packets of the first PDU Set from the source access network device are still sent to the terminal device when the first time delay is not satisfied, the terminal device will not have enough time to decode and display the first PDU Set, which will further lead to a waste of transmission resources.

[0028] Combined with the above third aspect, in a possible implementation, in the embodiments of the present application, the first time delay is determined according to the Packet Delay Budget (PSDB) of the first PDU Set, and the PSDB of the first PDU Set is used to characterize the transmission delay budget of the first PDU Set. (Without considering the case where the terminal device undergoes a handover, the PSDB of the first PDU Set is the upper limit requirement of the transmission delay used by the access network device to receive the first PDU Set and send the first PDU Set to the terminal device, or the upper limit requirement of the transmission delay used by the user plane function network element to receive the first PDU Set and send the first PDU Set to the terminal device; exemplarily, the access network device or the user plane function network element receiving the first PDU Set means receiving the first data packet of the first PDU Set.)

[0029] Combined with the above third aspect, in a possible implementation, the first time delay is determined according to the PSDB of the first PDU Set, including: the first time delay information is determined according to the PSDB of the first PDU Set and at least one of the following: the time when the source access network device receives the first data packet in the first PDU Set; the start time when the source access network device sends the untransmitted data packets in the first PDU Set to the target access network device; or, the link delay from the source access network device to the target access network device.

[0030] Combined with the above third aspect, in a possible implementation, the first information includes the first redundant packet ratio; wherein, the first redundant packet ratio is the ratio of the number of data packets included in the untransmitted data packets in the first PDU Set to the number of redundant packets corresponding to the untransmitted data packets in the first PDU Set, or the first redundant packet ratio is the upper limit of tolerable packet loss in the untransmitted data packets in the first PDU Set. This solution can avoid wasting transmission resources caused by still sending the data packets of the first PDU Set to the terminal device when the number of lost packets is greater than the maximum number of redundant packets corresponding to the first redundant packet ratio and the first PDU Set cannot be correctly decoded and displayed.

[0031] Combined with the above-mentioned third aspect, in a possible implementation manner, in the embodiments of the present application, the source access network device transmits the data packets in the first PDU Set that have not been transmitted to the target access network device, including: if the packet loss situation of the data packets that have been transmitted in a part of the first PDU Set sent to the terminal device meets the first condition, the source access network device transmits the data packets in the first PDU Set that have not been transmitted to the target access network device. In this solution, when the source access network device determines that the data packets that have been transmitted in a part of the first PDU Set currently sent to the terminal device can ensure the correct decoding of the first PDU Set, it transmits the data packets in the first PDU Set that have not been transmitted to the target access network device, avoiding the waste of transmission resources caused by transmitting the data packets in the first PDU Set that have not been transmitted to the target access network device when the first PDU Set cannot be correctly decoded.

[0032] Combined with the above-mentioned third aspect, in a possible implementation manner, the first condition is that no packet loss occurs.

[0033] Combined with the above-mentioned third aspect, in a possible implementation manner, the first condition is that the number of lost packets is less than or equal to the number of redundant data packets corresponding to the first PDU Set.

[0034] Combined with the above-mentioned third aspect, in a possible implementation manner, the communication method provided by the embodiments of the present application further includes: the source access network device sends the first indication information to the target access network device, and the first indication information is used to indicate that at least one first data packet being transmitted by the source access network device to the terminal device in the first PDU Set is lost. This solution enables the source access network device to timely notify the target access network device when it discovers that at least one first data packet being transmitted by the source access network device to the terminal device is lost, avoiding the waste of transmission resources caused by the target access network device still transmitting the data packets in the first PDU Set to the terminal device when at least one first data packet is lost and the first PDU Set cannot be correctly decoded.

[0035] Combined with the above-mentioned third aspect, in a possible implementation manner, the first indication information is further used to indicate the number of at least one first data packet with packet loss. This solution can enable the target access network device to determine the number of at least one first data packet with packet loss.

[0036] Combined with the above third aspect, in a possible implementation, the communication method provided by the embodiments of the present application further includes: the source access network device sends at least one first data packet to the target access network device. This solution can avoid that the target access network device does not send one or more data packets of the first PDU Set from the source access network device to the terminal device due to the loss of at least one first data packet being transmitted by the source access network device in the first PDU Set, and increases the transmission success rate of the data packets that have not been transmitted or have failed to be transmitted in the first PDU Set from the target access network device to the terminal device.

[0037] In a fourth aspect, a communication method is provided. This method can be executed by the target access network device, or by components of the target access network device, such as the processor, chip, or chip system of the target access network device, etc., and can also be implemented by a logic module or software that can implement all or part of the functions of the target access network device. Taking the case where this method can be executed by the target access network device as an example, this method includes: when the terminal device switches to the target access network device, the target access network device receives one or more data packets from the source access network device, and the one or more data packets are the data packets that have not been transmitted in the first protocol data unit set PDU Set, where at least one of the one or more data packets carries first information; the data packets that have not been transmitted in the first PDU Set are the remaining data packets after the source access network device sends part of the data packets of the first PDU Set to the terminal device; the target access network device processes the one or more data packets from the source access network device according to the first information.

[0038] In the communication method provided by the embodiments of the present application, the source access network device receives the first PDU Set from the user plane function network element and sends part of the data packets of the first PDU Set to the terminal device. When the terminal device switches to the target access network device, the source access network device sends the data packets that have not been transmitted in the first PDU Set to the target access network device, where at least one of the data packets that have not been transmitted in the first PDU Set carries first information, and the target access network device processes the one or more data packets received from the source access network device according to the first information. This solution ensures the joint transmission of the first PDU Set between the source access network device and the target access network device in the handover scenario. For example, the target access network device determines whether to transmit one or more data packets from the source access network device according to the first information, or the target access network device determines whether the one or more data packets received from the source access network device belong to the first PDU Set according to the first information.

[0039] Combined with the above fourth aspect, in a possible implementation manner, in the embodiments of the present application, the first information is determined by the source access network device according to the transmission status of the data packets in the first PDU Set sent to the terminal device. This solution can enable the target access network device to send one or more data packets from the source access network device to the terminal device more accurately. For example, the source access network device can determine the first redundancy packet ratio or packet loss indication carried in one or more data packets sent to the target access network device according to the packet loss situation of the data packets that have been transmitted in the data packets of the first PDU Set sent to the terminal device, avoiding the waste of transmission resources caused by still sending one or more data packets from the source access network device to the terminal device when packet loss occurs and the first PDU Set cannot be correctly decoded.

[0040] Combined with the above fourth aspect, in a possible implementation manner, the first information includes at least one of the following: the sequence number information of the first PDU Set, the sequence number information of each data packet in the first PDU Set, or the indication information of the last data packet in the first PDU Set. The target access network device processes one or more data packets from the source access network device according to the first information, including: the target access network device determines that one or more data packets received from the source access network device belong to the first PDU Set according to at least one of the sequence number information of the first PDU Set, the sequence number information of each data packet in the first PDU Set, or the indication information of the last data packet in the first PDU Set. This solution can enable the target access network device to send one or more data packets belonging to the first PDU Set received to the terminal device, thereby realizing the transmission processing at the PDU Set granularity. Among them, the data packets are transmitted in the form of PDU Sets, which can ensure that encoding and processing can be performed at the PDU Set granularity at the sending end, and decoding and display can be performed at the PDU Set granularity at the receiving end, thereby realizing the end-to-end service experience guarantee at the PDU Set granularity.

[0041] Combined with the above fourth aspect, in a possible implementation, the first information includes a first time delay, and the first time delay is used to indicate the transmission time delay budget of the data packets that have not been transmitted in the first PDU Set, or the transmission time delay budget of the data packets sent by the source access network device to the target access network device in the first PDU Set. Specifically, the first time delay may be the upper limit of the transmission time delay from the target access network device receiving the data packet that has not been transmitted in the first PDU Set to sending it to the terminal device. The target access network device processes one or more data packets from the source access network device according to the first information, including: when one or more data packets received from the source access network device meet the first time delay, the target access network device sends one or more data packets of the first PDU Set received from the source access network device to the terminal device. This solution can enable the target access network device to transmit one or more data packets of the first PDU Set received from the source access network device according to the received first time delay, and ensure that one or more data packets of the first PDU Set from the source access network device are sent to the terminal device within the first time delay range, ensuring that the transmission of the first PDU Set can meet the requirements of the transmission time delay budget. If one or more data packets that have not been transmitted in the first PDU Set from the source access network device are still sent to the terminal device when the first time delay is not met, the terminal device will not have enough time to decode and display the first PDU Set, which will result in a waste of transmission resources.

[0042] Combined with the above fourth aspect, in a possible implementation, in the embodiments of the present application, the first time delay is determined according to the per-packet delay budget (PSDB) of the first PDU Set, and the PSDB of the first PDU Set is used to represent the transmission time delay budget of the first PDU Set.

[0043] Combined with the above fourth aspect, in a possible implementation, the first time delay is determined according to the PSDB of the first PDU Set, including: the first time delay information is determined according to the PSDB of the first PDU Set and at least one of the following: the time when the source access network device receives the first data packet in the first PDU Set; the start time when the source access network device sends the data packets that have not been transmitted in the first PDU Set to the target access network device; or, the link time delay from the source access network device to the target access network device.

[0044] Combined with the above fourth aspect, in a possible implementation, the first information includes a first redundant packet ratio; wherein, the first redundant packet ratio is the ratio of the number of data packets included in the data packets not yet transmitted in the first PDU Set to the number of redundant packets corresponding to the data packets not yet transmitted in the first PDU Set, or the first redundant packet ratio is the upper limit of tolerable packet loss in the data packets not yet transmitted in the first PDU Set. The target access network device processes one or more data packets from the source access network device according to the first information, including: the target access network device determines a first quantity of data packets that are lost during the process of sending one or more data packets from the source access network device to the terminal device; in the case where the first quantity is greater than the number of redundant packets corresponding to the first redundant packet ratio, the target access network device determines not to send the data packets not yet transmitted in one or more data packets from the source access network device. This solution can avoid wasting transmission resources caused by still sending the data packets of the first PDU Set to the terminal device when the number of lost data packets is greater than the maximum number of redundant packets corresponding to the first redundant packet ratio and the first PDU Set cannot be correctly decoded and displayed.

[0045] Combined with the above fourth aspect, in a possible implementation, the packet loss situation of some data packets in the first PDU Set sent by the source access network device to the terminal device is that no packet loss occurs.

[0046] Combined with the above fourth aspect, in a possible implementation, the packet loss situation of some data packets in the first PDU Set sent by the source access network device to the terminal device is that the number of lost packets is less than or equal to the number of redundant data packets corresponding to the first PDU Set.

[0047] Combined with the above fourth aspect, the communication method provided by the embodiments of the present application further includes: the target access network device receives the lost data packets in the data packets that have been transmitted and completed in the first PDU Set from the source access network device. This solution can improve the transmission success rate of the first PDU Set.

[0048] Combined with the above fourth aspect, in a possible implementation, the communication method provided by the embodiments of the present application further includes: the target access network device receives first indication information from the source access network device, and the first indication information is used to indicate that at least one first data packet being transmitted by the source access network device to the terminal device in the first PDU Set is lost. This solution enables the source access network device to timely notify the target access network device when it discovers that at least one first data packet being transmitted by the source access network device to the terminal device is lost, and avoids wasting transmission resources caused by the target access network device still sending the data packets of the first PDU Set when at least one first data packet is lost and the first PDU Set cannot be correctly decoded.

[0049] Combined with the above fourth aspect, in a possible implementation, the first indication information is further used to indicate the number of at least one first data packet for which packet loss occurs. This solution enables the target access network device to determine the number of at least one first data packet for which packet loss occurs.

[0050] Combined with the above fourth aspect, in a possible implementation, the communication method provided by the embodiments of the present application further includes: the target access network device receives at least one first data packet from the source access network device. This solution can avoid the situation where the target access network device does not send one or more data packets of the first PDU Set from the source access network device to the terminal device due to packet loss of at least one first data packet being transmitted by the source access network device in the first PDU Set, and increases the transmission success rate of the data packets that have not been transmitted or have transmission failures in the first PDU Set from the target access network device to the terminal device.

[0051] In a fifth aspect, a communication device is provided for implementing the above various methods. The communication device can be the access network device in the first aspect, or a device included in the access network device, such as a chip; or, the communication device can be the first terminal device in the second aspect, or a device included in the first terminal device, such as a chip; or, the communication device can be the source access network device in the third aspect, or a device included in the source access network device, such as a chip; or, the communication device can be the target access network device in the fourth aspect, or a device included in the target access network device, such as a chip.

[0052] The communication device includes corresponding modules, units, or means for implementing the above methods. The module, unit, or means can be implemented by hardware, software, or by hardware executing corresponding software. The hardware or software includes one or more modules or units corresponding to the above functions.

[0053] In some possible designs, the communication device may include a processing module and a communication module. The communication module may include an output module (or a sending module) and an input module (or a receiving module), which are respectively used to implement the functions of the output type (or the sending type) and the input type (or the receiving type) in any of the above aspects and any of their possible designs. The processing module can be used to implement the processing functions in any of the above aspects and any of their possible designs.

[0054] Optionally, the communication device further includes a storage module for storing program instructions and data.

[0055] In a sixth aspect, a communication device is provided, including: at least one processor, which is used to run computer programs or instructions, or is used to enable the communication device to execute the method described in any of the above aspects through logic circuits. The communication device may be the access network device in the first aspect, or a device included in the access network device, such as a chip; or, the communication device may be the first terminal device in the second aspect, or a device included in the first terminal device, such as a chip; the communication device may be the source access network device in the third aspect, or a device included in the source access network device, such as a chip; the communication device may be the target access network device in the fourth aspect, or a device included in the target access network device, such as a chip.

[0056] In some possible designs, the communication device further includes a memory for storing computer instructions and / or configuration files of logic circuits. Optionally, the memory and the processor are integrated together, or the memory is independent of the processor.

[0057] In a possible design, the communication device further includes a communication interface for inputting and / or outputting signals.

[0058] In some possible designs, the communication interface is an interface circuit for reading and writing computer instructions. For example, the interface circuit is used to receive computer execution instructions (the computer execution instructions are stored in the memory, and may be directly read from the memory or may pass through other devices) and transmit them to the processor.

[0059] In some possible designs, the communication interface is used to communicate with modules outside the communication device.

[0060] In some possible designs, the communication device may be a chip system. When the communication device is a chip system, the chip system may include a chip, or may include a chip and other discrete devices.

[0061] In a seventh aspect, a communication device is provided, including: a logic circuit and an interface circuit; the interface circuit is used to input information and / or output information; the logic circuit is used to execute the method described in any of the above aspects, and process and / or generate output information according to the input information. The communication device may be the access network device in the first aspect, or a device included in the access network device, such as a chip; or, the communication device may be the first terminal device in the second aspect, or a device included in the first terminal device, such as a chip; or, the communication device may be the source access network device in the third aspect, or a device included in the source access network device, such as a chip; or the communication device may be the target access network device in the fourth aspect, or a device included in the target access network device, such as a chip.

[0062] It can be understood that when the communication device provided in any one of the fifth to seventh aspects is a chip, the above-mentioned sending action / function can be understood as outputting information, and the above-mentioned receiving action / function can be understood as inputting information.

[0063] In an eighth aspect, a computer-readable storage medium is provided. A computer program or instruction is stored in the computer-readable storage medium. When the computer program or instruction is executed by a processor, the method described in any one of the above aspects is executed.

[0064] In a ninth aspect, a computer program product is provided. When the computer program product is executed by a processor, the method described in any one of the above aspects is executed.

[0065] In a tenth aspect, a communication device is provided. The communication device includes modules / units for executing the method described in the first aspect, or the second aspect, or the third aspect, or the fourth aspect above.

[0066] In an eleventh aspect, a communication system is provided. The communication system includes the access network device described in the first aspect above and the first terminal device described in the second aspect; alternatively, the communication system includes the source access network device described in the third aspect above and the target access network device described in the fourth aspect.

[0067] Among them, for the technical effects brought by any one of the design manners in the fifth to eleventh aspects, reference can be made to the technical effects brought by different design manners in the first aspect, or the second aspect, or the third aspect, or the fourth aspect above, which will not be elaborated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0068] Figure 1 It is a schematic diagram of a 5G network architecture;

[0069] Figure 2 It is a schematic diagram of a layer 3 relay architecture;

[0070] Figure 3 It is a schematic diagram of a communication system provided by an embodiment of the present application;

[0071] Figure 4 It is a schematic diagram of another communication system provided by an embodiment of the present application;

[0072] Figure 5 It is a transmission schematic diagram of a first PDU Set in a handover scenario provided by an embodiment of the present application;

[0073] Figure 6 It is a schematic diagram of the structure of a communication device 600 provided by an embodiment of the present application;

[0074] Figure 7It is a schematic diagram of an example of the communication method provided by an embodiment of the present application;

[0075] Figure 8 It is a schematic diagram of another example of the communication method provided by an embodiment of the present application;

[0076] Figure 9 It is a schematic diagram of the communication device provided by an embodiment of the present application. Detailed implementation manners

[0077] The communication method provided by an embodiment of the present application can be applied to various communication systems, such as a wireless fidelity (Wi-Fi) network system, a vehicle to everything (V2X) communication system, a device-to-device (D2D) communication system, a vehicle networking communication system, a 4th generation (4G) mobile communication system, such as a long term evolution (LTE) communication system, a worldwide interoperability for microwave access (WiMAX) communication system, a 5th generation (5G) mobile communication system (such as a new radio (NR) system), or a future communication system, such as 5.5G, a 6th generation (6G) mobile communication system, etc.

[0078] For ease of understanding, the related technologies of the embodiments of the present application are briefly introduced first.

[0079] Related technology 1. 5th generation (5G) network architecture:

[0080] The 5G network architecture defined in the 3rd generation partnership project (3GPP) standard is mainly divided into two parts: an access network (AN) and a core network. As Figure 1 shown, the terminal device accesses the core network through the access network.

[0081] Among them, as Figure 1As shown, the access network may include radio access network (RAN) devices for implementing functions related to wireless access. The core network mainly includes the following key logical network elements: access and mobility management function (AMF) network element, session management function (SMF) network element, user plane function (UPF) network element, policy control function (PCF) network element, unified data management (UDM) network element. In addition, it may also include an authentication server function (AUSF) network element, a network slice selection function (NSSF) network element, an application function (AF) network element, etc. The following briefly introduces Figure 1 the relevant network elements shown.

[0082] DN is the data network (DN), mainly used to provide data transmission services for users, such as Internet Protocol (IP) multimedia services (IP Multi-media Service, IMS), etc.

[0083] RAN devices include, but are not limited to, evolved base stations (NodeB or eNB or e-NodeB, evolutional NodeB), wireless fidelity (WiFi) access points (access point, AP), etc.

[0084] The AMF network element is mainly responsible for mobility management in the mobile network, such as user location update, user registration to the network, user handover, etc.

[0085] The SMF network element is mainly responsible for session management in the mobile network, such as session establishment, modification, and release. Specific functions include allocating IP addresses for users, selecting UPFs that provide packet forwarding functions, etc.

[0086] The PCF network element is mainly responsible for providing policies to the AMF and SMF, such as quality of service (QoS) policies, slice selection policies, etc.

[0087] The UDM network element is mainly responsible for storing user data, such as subscription information, authentication / authorization information.

[0088] The AF network element is mainly responsible for providing service requirements to the 3GPP network, such as influencing service routing, interacting with the PCF network element for policy control, etc.

[0089] The UPF network element is mainly responsible for processing user packets, such as forwarding, charging, etc.

[0090] The terminal device accesses the DN by establishing a Protocol Data Unit (PDU) session between the terminal, RAN, UPF, and DN.

[0091] The AUSF network element is mainly responsible for providing authentication services for the terminal device to the AMF network element.

[0092] The NSSF network element is mainly responsible for selecting the network slice that serves the terminal device.

[0093] In addition, referring to Figure 1 , Nx represents the logical interface or service-based interface between two network elements, which is used for communication between network elements. For example, N1 is the interface between the terminal device and the AMF network element; N2 is the interface between the access network device and the AMF network element; N3 is the interface between the access network device and the UPF network element; N9 is the interface between different UPF network elements; N6 is the interface between the UPF network element and the DN; N4 is the interface between the UPF network element and the SMF network element; N11 is the interface between the AMF network element and the SMF network element; N7 is the interface between the SMF network element and the PCF network element; N5 is the interface between the PCF network element and the AF network element; N14 is the interface between different AMF network elements; N15 is the interface between the AMF network element and the PCF network element; N22 is the interface between the NSSF network element and the AMF network element; N12 is the interface between the AUSF network element and the AMF network element; N8 is the interface between the UDM network element and the AMF network element; N13 is the interface between the AUSF network element and the UDM network element.

[0094] Related technology 2. Proximity based services (ProSe) communication:

[0095] ProSe communication, also known as proximity service communication, is a typical service scenario in D2D communication. ProSe communication can include direct communication of proximity services and communication from a proximity service terminal device to a network relay. For communication from a proximity service terminal device to a network relay (which can be simply referred to as ProSe relay communication), when a certain terminal device (denoted as terminal device 1) is outside the network coverage, or has poor communication signals with the RAN device, or needs other terminal devices (denoted as terminal device 2) to assist in data transmission, terminal device 1 can obtain services from the network with the assistance of terminal device 2. At this time, terminal device 1 can be called a proximity service remote terminal device (ProSe remote UE), or a 5G proximity service remote terminal device (5G ProSe remote UE), or simply a remote terminal device (remote UE). Terminal device 2 can be called a proximity service terminal device to network relay (ProSe UE-to-network relay), or a 5G proximity service terminal device to network relay (5G ProSe UE-to-network relay), or simply a relay terminal device (relay UE). The relay terminal device can be used to provide the ProSe function to support the connection of the remote terminal device to the network, so that the remote terminal device can communicate with the DN through the ProSe function provided by the relay terminal device, that is, ProSe relay communication.

[0096] To support the ProSe function, 3GPP has introduced a layer 3 relay architecture.

[0097] Figure 2 Figure for the architecture diagram of the layer 3 relay architecture. As Figure 2As shown, the remote terminal device establishes a PC5 connection with the relay terminal device, and the relay terminal device accesses the 5G core network (5G core, 5GC) through the RAN device. In this way, the remote terminal device obtains services from the DN through the PC5 connection and the 5G core network accessed by the relay terminal device, realizing ProSe communication. For example, the relay terminal device can establish or modify a protocol data unit (PDU) session for the remote terminal device and notify the SMF network element to store the relevant information of the remote terminal device in the session management (SM) context. In this way, the remote terminal device can obtain services from the DN through the PDU session of the relay terminal device, realizing ProSe communication. Alternatively, the relay terminal device can also establish or modify a PDU session for the remote terminal device so that the remote terminal device can establish an IPsec tunnel for signaling with the non-3GPP interworking function (N3IWF) through the IKE (Internet Key Exchange) process of this PDU session and execute the non-access stratum (NAS) registration process. In this way, the remote terminal device can establish a PDU session of the remote terminal device with the N3IWF through the PDU session established by the relay terminal device and obtain services from the DN, realizing ProSe relay communication. In addition, the relay terminal device can be located in the home public land mobile network (PLMN) or in the visited PLMN, and no specific limitation is made in this regard.

[0098] It should be noted that in the layer 3 relay architecture, the remote terminal device can be referred to as a 5G ProSe layer 3 remote terminal device, a ProSe layer 3 remote terminal device, or a layer 3 remote terminal device.

[0099] Related technology 3. Quality of service (QoS) flow.

[0100] In a 5G communication system (5G system, 5GS), when a terminal device has a service communication requirement, a PDU session is established. Specifically, the corresponding QoS flow carries the service flow in the PDU session. Specifically, the terminal device obtains an Internet Protocol (IP) address through the PDU session establishment process to interact with an external service server and achieve service communication. The 5GS maps the corresponding service to different QoS flows based on service flow description information and performs corresponding QoS processing.

[0101] Related technology 4. QoS processing mechanism at the PDU Set granularity.

[0102] The 5GC schedules, processes, and transmits all the data packets within the PDU Set as a whole by identifying the relationship between different data packets and the PDU Set, ensuring the user's service experience.

[0103] To determine which data packets in the QoS flow belong to the same PDU Set, after the downlink data packets arrive at the UPF network element, the UPF network element determines the PDU Set accordingly and adds the corresponding PDU Set information to the data packets in the downlink PDU Set. The PDU Set information includes PDU Set sequence number information (PSSN), PDU Set size information, indication information of the last data packet within the PDU Set, PDU Set importance information (PSI), etc. The PDU Set information is added to the General Packet Radio Service (GPRS) tunneling protocol - user plane (GTP - U) layer of the data packets in the PDU Set to assist the RAN device in performing PDU Set QoS processing.

[0104] Before this process, the RAN device receives PDU Set QoS parameters from the SMF network element. The PDU Set QoS parameters include the transmission delay budget of the PDU Set (PDU Set delay budget, PSDB), the PDU Set error rate (PDU Set error rate, PSER), the PDU Set integrity processing information (for example, the data packets in the PDU Set need to be transmitted successfully in a complete manner, and packet loss or damage is not tolerated), etc. Among them, the PSDB is used to characterize the time required for each PDU Set transmission, that is, the time required for each PDU Set to be transmitted from the UPF network element to the RAN device and then to the terminal device. Specifically, the PSDB refers to the upper limit of the transmission delay required for the UPF network element to receive the first data packet of the PDU Set and transmit it to the terminal device. Alternatively, the PSDB can also be the upper limit of the transmission time required for each PDU Set to be transmitted from the RAN device to the terminal device. In this case, the PSDB is also referred to as the RAN device PSDB. In the embodiments of this application, if the transmission between the RAN device and the terminal device is involved, the PSDB actually refers to the RAN device PSDB, that is, the upper limit of the transmission delay required for the RAN device to receive the first data packet of the PDU Set and transmit the PDU Set to the terminal device.

[0105] The RAN device performs PDU Set processing based on the PDU Set information and PDU Set QoS parameters in the downlink data packet.

[0106] Related art 5. Packet transmission failure (packet loss) scenario.

[0107] In a possible implementation, when a data packet is transmitted between the RAN device and the terminal device, if the delay required for the data packet transmission exceeds the data packet transmission delay budget of the data packet, it can be considered that the data packet is lost. Specifically, when the data packet transmission delay budget is exhausted and the radio link control (RLC) layer has not had time to send the data packet to the media access control (MAC) layer for transmission and the data packet is still in the RLC buffer, it will be considered that the data packet is lost. Among them, the data packet transmission delay budget for the data packet transmitted between the RAN device and the terminal device is the access network data packet transmission delay budget.

[0108] In another possible implementation, there is a feedback mechanism between the RAN device and the terminal device, that is, the RAN device determines whether a data packet is successfully transmitted according to the feedback from the terminal device. Specifically, when the data packet is sent to the MAC layer for transmission, the MAC layer determines whether the data packet will be successfully transmitted finally according to the feedback of the hybrid automatic repeat-request (HARQ): the MAC layer saves the mapping relationship between the data packet and the MAC layer transmission data block (the MAC layer may split and reorganize the upper-layer data packet to ensure that the data packet is suitable for channel transmission). Further, the MAC layer feeds back to the upper-layer RLC or packet data convergence protocol (PDCP). This implementation ensures that the RAN device can perceive the packet loss situation of each data packet during scheduling transmission. It should be noted that the specific implementation will ultimately depend on the RAN device product implementation.

[0109] Related technology 6. Processing scenarios of PDU Set.

[0110] Depending on the application layer implementation, there are the following scenarios for the processing of PDU Set:

[0111] Processing scenario 1:

[0112] The loss or corruption of a data packet in the PDU Set will make it difficult to correctly decode and display the entire PDU Set.

[0113] Processing scenario 2:

[0114] When some data packets in the PDU Set are lost or corrupted, the receiving-side client can recover, decode, and display the data packets before the first lost data packet in the received PDU Set, but the subsequent data packets are difficult to correctly decode and display.

[0115] Processing scenario 3:

[0116] Before sending a PDU Set, the sender at the service layer / application layer performs forward error correction (FEC) on the current PDU Set, that is, by adding extra redundant data packets to avoid the degradation of the service experience caused by packet loss during transmission. There is a maximum limit on the number of redundant packets in each PDU Set. If the number of lost data packets in a PDU Set exceeds the maximum number of redundant packets, it will be difficult to correctly decode and display the entire PDU Set. For example, a PDU Set contains 30 data packets. After FEC, the PDU Set contains 40 data packets, including 10 redundant data packets. During the transmission of this PDU Set, the number of lost packets within 10 or less than 10 does not affect the correct decoding and display of this PDU Set. It should be noted that in the following embodiments, if the processing scenario three is involved, that is, the PDU Set has undergone FEC processing, it is considered that the PDU Set contains redundant data packets.

[0117] After at least one of the above three processing scenarios occurs, generally, the RAN device does not send the remaining data packets (packets that have not been transmitted) within the PDU Set.

[0118] Next, the communication method provided by the embodiments of the present application will be introduced.

[0119] In the description of the present application, unless otherwise specified, " / " means that the objects associated before and after are in an "or" relationship. For example, A / B may represent A or B; "and / or" in the present application is only a description of the association relationship of the associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. Here, A and B can be singular or plural.

[0120] In the description of the present application, unless otherwise specified, "a plurality of" means two or more than two. "At least one (or more) of the following or similar expressions refers to any combination of these items, including any combination of single item (or more) or plural items (or more). For example, at least one (or more) of a, b, and (or) c can represent: a, b, c, a - b, a - c, b - c, or a - b - c, where a, b, and c can be single or multiple.

[0121] In addition, in order to clearly describe the technical solutions of the embodiments of the present application, in the embodiments of the present application, terms such as "first" and "second" are used to distinguish the same items or similar items with basically the same functions and effects. Those skilled in the art can understand that the terms "first", "second", etc. do not limit the quantity and execution order, and the terms "first", "second", etc. do not necessarily mean different.

[0122] In the embodiments of the present application, words such as "exemplary" or "for example" are used to represent examples, illustrations or explanations. Any embodiment or design solution described as "exemplary" or "for example" in the embodiments of the present application should not be construed as being more preferred or advantageous than other embodiments or design solutions. Rather, the use of words such as "exemplary" or "for example" is intended to present relevant concepts in a specific manner for easy understanding.

[0123] It can be understood that the "embodiments" mentioned throughout the specification mean that specific features, structures or characteristics related to the embodiments are included in at least one embodiment of the present application. Therefore, throughout the specification, the various embodiments do not necessarily refer to the same embodiment. In addition, these specific features, structures or characteristics can be combined in one or more embodiments in any suitable manner. It can be understood that in the various embodiments of the present application, the magnitude of the serial numbers of the various processes does not mean the order of execution, and the execution order of the various processes should be determined according to their functions and internal logics, and should not constitute any limitation to the implementation process of the embodiments of the present application.

[0124] It can be understood that some optional features in the embodiments of the present application, in some scenarios, can be implemented independently without relying on other features, such as the current solution they are based on, to solve the corresponding technical problems and achieve the corresponding effects. In some scenarios, they can also be combined with other features according to requirements. Correspondingly, the devices given in the embodiments of the present application can also implement these features or functions accordingly, which will not be elaborated here.

[0125] In the present application, unless otherwise specified, the same or similar parts between the various embodiments can be referred to each other. In the various embodiments of the present application, if there is no special specification and logical conflict, the terms and / or descriptions between different embodiments are consistent and can be mutually referred to, and the technical features in different embodiments can be combined to form new embodiments according to their internal logical relationships. The embodiments of the present application described below do not constitute a limitation to the protection scope of the present application.

[0126] To facilitate the understanding of the embodiments of the present application, first, a communication system in a cascaded scenario shown in Figure 3 and a communication system in a handover scenario shown in Figure 4 will be taken as examples to illustrate in detail the communication system applicable to the embodiments of the present application.

[0127] Exemplarily, Figure 3 is a schematic diagram of a communication system provided by an embodiment of the present application. As Figure 3 shown, the communication system includes: an access network device and a first terminal device.

[0128] An access network device, configured to receive first indication information from a session management function network element, where the first indication information is used to indicate that the access network device adds first information to a first PDU Set, and the first information is used for a first terminal device to send the first PDU Set to a second terminal device.

[0129] The access network device is further configured to receive one or more data packets of the first PDU Set from a user plane function network element, and send the one or more data packets of the first PDU Set to the first terminal device, where at least one of the one or more data packets of the first PDU Set sent by the access network device to the first terminal device carries the first information.

[0130] The first terminal device is configured to receive one or more data packets from the access network device, and process the data packets of the first PDU Set according to the first information.

[0131] Optionally, as Figure 3 shown, the communication system includes a session management function network element and / or a user plane function network element.

[0132] The session management function network element is configured to send the first indication information to the access network device.

[0133] The user plane function network element is configured to send one or more data packets of the first PDU Set to the access network device.

[0134] Optionally, as Figure 3 shown, the communication system further includes: a second terminal device, configured to receive the data packets of the first PDU Set from the first terminal device.

[0135] Optionally, in a cascaded scenario, the first terminal device may be a relay terminal device in a layer 3 relay architecture as Figure 2 shown, and the second terminal device may be a remote terminal device in a layer 3 relay architecture as Figure 2 shown.

[0136] Exemplarily, Figure 4 is a schematic diagram of another communication system provided by an embodiment of this application. As Figure 4 shown, the communication system includes: a source access network device, a target access network device, and a terminal device.

[0137] The source access network device is configured to receive the first PDU Set from the user plane function network element and send partial data packets of the first PDU Set to the terminal device.

[0138] When the terminal device switches to the target access network device, the source access network device is further configured to send the data packets in the first PDU Set that have not been transmitted to the target access network device. At least one of the data packets in the first PDU Set that have not been transmitted carries first information, and the first information is used to transmit the data packets in the first PDU Set that have not been transmitted.

[0139] The target access network device is configured to receive one or more data packets from the source access network device and process the one or more data packets from the source access network device according to the first information.

[0140] Optionally, in the embodiments of the present application, the target access network device is further configured to send one or more data packets from the source access network device to the terminal device. The terminal device is configured to receive partial data packets of the first PDU Set from the source access network device.

[0141] Optionally, the terminal device is further configured to receive one or more data packets from the target access network device.

[0142] Optionally, as Figure 4 shown, the communication system includes a user plane function network element.

[0143] For example, Figure 5 shows a schematic diagram of the transmission of the first PDU Set in a handover scenario. As Figure 5 shown, before the terminal device switches to the target access network device, the source access network device sends partial data packets of the first PDU Set to the terminal device; when the terminal device switches to the target access network device, the source access network device sends the data packets in the first PDU Set that have not been transmitted to the target access network device. Further, the target access network device may send one or more data packets from the source access network device to the terminal device.

[0144] Optionally, the terminal device involved in the present application (for example, Figure 3 the first terminal device and the second terminal device in the communication system shown, or, Figure 4The terminal device in the communication system shown) can be a user equipment (UE), access terminal, terminal unit, user station, terminal station, mobile station, mobile device, remote station, remote terminal, user terminal, terminal equipment (TE), mobile device, wireless communication device, terminal agent, tablet computer (pad), handheld device with wireless communication function, computing device or other processing device connected to a wireless modem, vehicle-mounted device, vehicle-mounted communication module, wearable device, or terminal device. The access terminal can be a cellular phone, cordless phone, session initiation protocol (SIP) phone, wireless local loop (WLL) station, personal digital assistant (PDA), handheld device with wireless communication function, computing device or other processing device connected to a wireless modem, vehicle-mounted device, drone, robot, intelligent point of sale (POS) machine, customer-premises equipment (CPE) or wearable device, virtual reality (VR) terminal device, augmented reality (AR) terminal device, wireless terminal in industrial control, wireless terminal in self-driving, wireless terminal in remote medical, wireless terminal in smart grid, wireless terminal in transportation safety, wireless terminal in smart city, wireless terminal in smart home, etc. Alternatively, the terminal can be a terminal with communication function in the internet of things (IoT), such as a terminal in V2X (e.g., vehicle-to-everything device), a terminal in D2D communication, or a terminal in M2M communication, etc. The terminal can be mobile or fixed. In addition, the embodiments of the present application do not limit the device form of the terminal. The device for implementing the function of the terminal device can be the terminal device; it can also be a device capable of supporting the terminal device to implement this function, such as a chip system. The device can be installed in the terminal device or used in matching with the terminal device. In the embodiments of the present application, the chip system can be composed of chips or can include chips and other discrete devices.

[0145] Optionally, the access network device involved in the present application (for example, Figure 3 the access network device in the communication system shown, or, Figure 4 the source access network device and the target access network device in the communication system shown), may be an evolved Node B (NodeB or eNB or e-NodeB, evolutional Node B) in a Long Term Evolution (LTE) system or an enhanced LTE (LTE-Advanced, LTE-A) system, such as a traditional macro eNB and a micro eNB in a heterogeneous network scenario. Alternatively, it may include a next generation Node B (gNB) in a New Radio (NR) system. Alternatively, it may include a Transmission Reception Point (TRP), a Home evolved NodeB (for example, home evolved NodeB, or home Node B, HNB), a Base Band Unit (BBU), a BBU pool, or a Wireless Fidelity (WiFi) Access Point (AP), etc. Alternatively, it may include a base station in a Non-Terrestrial Network (NTN), that is, it may be deployed on an airborne platform or a satellite. In the NTN, the access network device may act as a Layer 1 (L1) relay, or may act as a base station, or may act as an Integrated Access and Backhaul (IAB) node. Alternatively, the access network device may be a device that implements the base station function in the IoT, such as a device that implements the base station function in drone communication, V2X, D2D, or Machine-to-Machine (M2M).

[0146] In some possible scenarios, the access network device may also be a module or unit capable of implementing some functions of the base station. For example, the first network device may be a central unit (CU), a distributed unit (DU), a CU - control plane (CP), a CU - user plane (UP), or a radio unit (RU), etc. The CU and the DU may be set separately, or may also be included in the same network element, such as a baseband unit (BBU). The RU may be included in a radio frequency device or a radio frequency unit, such as included in a remote radio unit (RRU), an active antenna unit (AAU), or a remote radio head (RRH).

[0147] In different systems, the CU (or CU - CP and CU - UP), DU, or RU may also have different names, but those skilled in the art can understand their meanings. For example, the access network device may be a network device or a module of a network device in an open radio access network (ORAN) system. In the ORAN system, the CU may also be called an open (O) - CU, the DU may also be called an O - DU, the CU - CP may also be called an O - CU - CP, the CU - UP may also be called an O - CU - UP, and the RU may also be called an O - RU. Any one of the CU (or CU - CP, CU - UP), DU, and RU in this application may be implemented by a software module, a hardware module, or a combination of a software module and a hardware module.

[0148] Optionally, the base stations in the embodiments of this application may include various forms of base stations, such as: macro base stations, micro base stations (also called small stations), relay stations, access points, home base stations, TRPs, transmitting points (TPs), mobile switching centers, etc. The embodiments of this application do not make specific limitations on this.

[0149] Optionally, the user plane function network element involved in this application may be a UPF network element in a 5G communication architecture, or a network element with the function of a user plane function network element in other communication systems. The session management function network element involved in this application may be an SMF network element in a 5G communication architecture, or a network element with the function of a session management function network element in other communication systems. This application does not make limitations on this.

[0150] The related functions of the access network devices (source access network device, target access network device) and terminal devices (first terminal device, second terminal device) involved in this application can be achieved throughFigure 6 It is implemented by the communication device 600 in Figure 6 FIG. It is a schematic structural diagram of the communication device 600 provided in the embodiment of the present application. The communication device 600 includes one or more processors 601, a communication line 602, and at least one communication interface ( Figure 6 In

[0151] The processor 601 may be a general-purpose central processing unit (CPU), a microprocessor, an application-specific integrated circuit (ASIC), or one or more integrated circuits for controlling the execution of the program of the solution of the present application.

[0152] The communication line 602 may include a path for connecting different components.

[0153] The communication interface 604 may be a transceiver module for communicating with other devices or communication networks, such as Ethernet, RAN, wireless local area networks (WLAN), etc. For example, the transceiver module may be a device such as a transceiver or a transceiver. Optionally, the communication interface 604 may also be a transceiver circuit located within the processor 601 to implement signal input and signal output of the processor.

[0154] The memory 603 may be a device with a storage function. For example, it may be a read-only memory (ROM) or other types of static storage devices that can store static information and instructions, a random access memory (RAM) or other types of dynamic storage devices that can store information and instructions, or it may also be an electrically erasable programmable read-only memory (EEPROM), a compact disc read-only memory (CD-ROM) or other optical disc storage, optical disc storage (including compact discs, laser discs, optical discs, digital versatile discs, Blu-ray discs, etc.), magnetic disk storage media or other magnetic storage devices, or any other medium that can be used to carry or store the desired program code in the form of instructions or data structures and can be accessed by a computer, but is not limited thereto. The memory may exist independently and be connected to the processor through the communication line 602. The memory may also be integrated with the processor.

[0155] Among them, the memory 603 is used to store computer-executable instructions for executing the solution of this application, and is controlled by the processor 601 to execute. The processor 601 is used to execute the computer-executable instructions stored in the memory 603, so as to implement the communication method provided in the embodiments of this application.

[0156] Alternatively, optionally, in the embodiments of this application, it may also be that the processor 601 executes the functions related to processing in the communication method provided in the following embodiments of this application, and the communication interface 604 is responsible for communicating with other devices or communication networks. The embodiments of this application do not make specific limitations on this.

[0157] Optionally, the computer-executable instructions in the embodiments of this application may also be referred to as application code. The embodiments of this application do not make specific limitations on this.

[0158] In a specific implementation, as an embodiment, the processor 601 may include one or more CPUs, such as Figure 6 CPU0 and CPU1 in

[0159] In a specific implementation, as an embodiment, the communication device 600 may include multiple processors, such as Figure 6 processor 607 and processor 601 in

[0160] Each of these processors may be a single-core processor or a multi-core processor. The processors here may include but are not limited to at least one of the following: central processing unit (CPU), microprocessor, digital signal processor (DSP), microcontroller unit (MCU), or artificial intelligence processor and other types of computing devices that run software. Each computing device may include one or more cores for executing software instructions to perform operations or processing.

[0161] The above-mentioned communication device 600 may sometimes also be referred to as a communication device, which may be a general-purpose device or a dedicated device. For example, the communication device 600 may be a desktop computer, a laptop computer, a network server, a personal digital assistant (PDA), a mobile phone, a tablet computer, a wireless terminal device, an embedded device, or a device having a Figure 6 similar structure in

[0162] In addition, Figure 6 the constituent structure shown in Figure 6 does not constitute a limitation on the communication device. Except for

[0163] The communication method provided by the embodiments of the present application will be described below in conjunction with Figure 3 or Figure 4 the communication system shown in

[0164] It should be noted that in the following embodiments of the present application, the message names between each network element, the names of each parameter, or the names of each piece of information, etc. are only examples, and in other embodiments, they may also be other names. The communication method provided by the present application does not make specific limitations on this.

[0165] It can be understood that in the embodiments of the present application, each network element may execute some or all of the steps in the embodiments of the present application. These steps or operations are only examples, and the embodiments of the present application may also execute other operations or various deformations of the operations. In addition, each step may be executed in a different order presented in the embodiments of the present application, and it is possible that not all of the operations in the embodiments of the present application need to be executed.

[0166] Figure 7 is a schematic diagram of an example of the communication method provided by the embodiments of the present application. This method can be applied to, for example, Figure 3The communication system shown is described by taking the interaction of a session management function network element, a user plane function network element, an access network device, a first terminal device, and a second terminal device as an example. Of course, the entity that executes the actions of the session management function network element in this method can also be a device / module in the session management function network element, such as a chip, a processor, a processing unit, etc. in the session management function network element; the entity that executes the actions of the user plane function network element in this method can also be a device / module in the user plane function network element, such as a chip, a processor, a processing unit, etc. in the user plane function network element; the entity that executes the actions of the access network device in this method can also be a device / module in the access network device, such as a chip, a processor, a processing unit, etc. in the access network device; the entity that executes the actions of the first terminal device in this method can also be a device / module in the first terminal device, such as a chip, a processor, a processing unit, etc. in the first terminal device; the entity that executes the actions of the second terminal device in this method can also be a device / module in the second terminal device, such as a chip, a processor, a processing unit, etc. in the second terminal device. The embodiments of the present application do not make specific limitations on this. In the embodiments of the present application, the processing executed by a single execution entity (for example, an access network device, a first terminal device, or a second terminal device) can also be divided into being executed by multiple execution entities, and these execution entities can be logically and / or physically separated. Exemplarily, as Figure 7 shown, method 700 includes the following steps:

[0167] S710, the session management function network element sends first indication information to the access network device. Correspondingly, the access network device receives the first indication information from the session management function network element.

[0168] In the embodiments of the present application, the first indication information is used to instruct the access network device to add first information to the first PDU Set. Exemplarily, the first indication information is used to instruct the access network device to add first information to the first PDU Set sent to the first terminal device. In the embodiments of the present application, the first information is used for the first terminal device to process the data packets of the first PDU Set according to the first information when sending the first PDU Set to the second terminal device.

[0169] In the embodiments of the present application, the first indication information can also be pre-configured in the access network device, that is, the access network device does not need to receive the first indication information, and the access network device adds the first information to the first PDU Set according to the pre-configuration. If the first indication information is pre-configured in the access network device, then step S710 is optional.

[0170] Exemplarily, the first indication information may be a specially configured 5G QoS identifier (5G QoS identifier, 5QI), and the specially configured 5QI instructs the access network device to add the first information to the first PDU Set. For example, the specially configured 5QI is configured by the operator, and the value of the specially configured 5QI is "200", then it can instruct the access network device to add the first indication information to the first PDU Set.

[0171] In a possible implementation manner, the first indication information is only used to instruct the access network device to add the first information to the first PDU Set, and the access network device determines in which or which data packets of the first PDU Set sent to the first terminal device to add the first information. Optionally, the access network device adds the first information to the first packet in the first PDU Set sent to the first terminal device; or, optionally, the access network device adds the first information to each data packet in the first PDU Set sent to the first terminal device; or, optionally, the access network device adds the first information to the first packet and some other data packets in the first PDU Set sent to the first terminal device. For example, the first PDU Set includes 20 data packets, and the access network device adds the first information to the first 10 data packets; or, optionally, the access network device adds the first information to the first packet and 10 data packets with even serial numbers; or, optionally, the access network device adds the first information to 10 data packets with odd serial numbers; or, optionally, the access network device adds the first information to the first packet and other random data packets; or, optionally, the access network device selects the data packets in the first PDU Set to which the first information is to be added according to other rules, and the embodiments of the present application do not limit this.

[0172] In another possible implementation, the first indication information is used to indicate in which packet or packets of the first PDU Set the access network device adds the first information. Optionally, the first indication information is used to indicate that the access network device adds the first information to the first packet of the first PDU Set; or, optionally, the first indication information is used to indicate that the access network device adds the first information to each packet of the first PDU Set; or, optionally, the first indication information is used to indicate that the access network device adds the first information to the first packet and some other packets of the first PDU Set. For example, if the first PDU Set includes 20 packets, the first indication information is used to indicate that the access network device adds the first information to the first 10 packets; or, optionally, the first indication information is used to indicate that the access network device adds the first information to the first packet and 10 packets with even sequence numbers; or, optionally, the first indication information is used to indicate that the access network device adds the first information to 10 packets with odd sequence numbers; or, optionally, the first indication information is used to indicate that the access network device adds the first information to the first packet and some other random packets; or, optionally, the first indication information is used to indicate that the access network device adds the first information to the packets of the first PDU Set according to other rules. The embodiments of the present application do not limit this.

[0173] It should be noted that adding the first information to the first packet can ensure that the method of the embodiments of the present application achieves better technical effects. The solution of not adding the first information to the first packet is also within the protection scope of the embodiments of the present application. The embodiments of the present application are introduced by taking adding the first information to the first packet as an example. It should be noted that the first packet of the first PDU Set can usually be received.

[0174] Optionally, in the embodiments of the present application, the first indication information is sent by the session management function network element to the access network device according to the fact that the first terminal device is connected to the second terminal device; or, optionally, the first indication information is sent by the policy control function network element to the session management function network element to indicate the session management function network element to send to the access network device according to the fact that the first terminal device is connected to the second terminal device; or, optionally, the first indication information is sent by the session management function network element to the access network device according to other information, such as the session management network element determines based on the information provided by the third-party application side through the policy control network element. The embodiments of the present application do not limit this.

[0175] Exemplarily, the first terminal device is the relay terminal device introduced in Related Art 2, such as a mobile phone; the second terminal device is the remote terminal device introduced in Related Art 2, such as an AR glasses.

[0176] S720, the user plane function network element sends one or more packets of the first PDU Set to the access network device. Correspondingly, the access network device receives one or more packets of the first PDU Set from the user plane function network element.

[0177] In the embodiments of the present application, one or more data packets of the first PDU Set sent by the user plane function network element to the access network device include the first PDU Set information, which can refer to the relevant description of Related Art 4 and will not be elaborated here.

[0178] Optionally, in the embodiments of the present application, one or more data packets of the first PDU Set sent by the user plane function network element to the access network device include the data packets that the user plane function network element is sending to the access network device and the data packets received by the access network device from the user plane function network element. Exemplarily, the data packets of the first PDU Set sent by the user plane function network element to the access network device are Data Packet 1 - Data Packet 10 (in the following examples, it is assumed that the data packets of the first PDU Set are sent in ascending order of the packet numbers, and this will not be elaborated further), and the data packets of the first PDU Set received by the access network device from the user plane function network element are Data Packet 1 - Data Packet 8, and Data Packets 9 - 10 are in the process of transmission.

[0179] Through the above example, it can be understood that one or more data packets of the first PDU Set sent by the user plane function network element to the access network device are not equivalent to one or more data packets of the first PDU Set received by the access network device from the user plane function network element. Similarly, one or more data packets of the first PDU Set sent by the access network device to the first terminal device in S730 below are not equivalent to one or more data packets received by the first terminal device from the access network device. This is uniformly explained here and will not be elaborated further.

[0180] Under normal circumstances, there is no packet loss during the process of the user plane function network element sending the data packets of the first PDU Set to the access network device. Therefore, the embodiments of the present application do not introduce in detail the situation of packet loss during the process of the user plane function network element sending the data packets of the first PDU Set to the access network device.

[0181] S730, the access network device sends one or more data packets of the first PDU Set to the first terminal device. Correspondingly, the first terminal device receives one or more data packets from the access network device.

[0182] In the embodiments of the present application, one or more data packets of the first PDU Set sent by the access network device to the first terminal device are some or all of the one or more data packets received by the access network device from the user plane function network element. That is, the access network device does not immediately send all the data packets received from the user plane function network element to the first terminal device. For example, the data packets of the first PDU Set received by the access network device from the user plane function network element are data packets 1 to 10, and the access network device gradually sends one or more data packets of the first PDU Set to the first terminal device. For example, at time 1, data packets 1 to 8 are sent (in this example, it is assumed that the one or more data packets of the first PDU Set sent by the access network device to the first terminal device carry the sequence number information of each data packet in the first PDU Set included in the following first information, or may not carry the sequence number information. The access network device sends 8 data packets of the first PDU Set to the first terminal device), and at a subsequent time 2, data packets 9 to 10 are sent. It can be understood that the access network device receives one or more data packets of the first PDU Set from the user plane function network element while sending one or more of the one or more data packets of the received first PDU Set to the first terminal device.

[0183] In the embodiments of the present application, at least one of the one or more data packets of the first PDU Set sent by the access network device to the first terminal device carries the first information, and the first information carried in the at least one data packet is added by the access network device according to the first indication information. Correspondingly, at least one of the one or more data packets received by the first terminal device from the access network device carries the first information, where the one or more data packets belong to the first PDU Set.

[0184] Optionally, in the embodiments of the present application, the first information is carried in the packet header of the data packet; optionally, the first information is carried in other positions of the data packet, and the embodiments of the present application do not make any limitations in this regard. Exemplarily, the first information may be carried in the PDCP layer or the service data adaptation protocol (SDAP) layer of the downlink data packet, and the embodiments of the present application do not make any limitations in this regard.

[0185] It should be noted that one or more data packets of the first PDU Set sent by the user plane function network element to the access network device do not carry the first information. At least one data packet of the one or more data packets of the first PDU Set sent by the access network device to the first terminal device carries the first information. The data packets of the first PDU Set sent by the first terminal device to the second terminal device in the following step S750 do not carry the first information. Since the identifier of the first PDU Set transmitted in the three processes, such as the sequence number information of the first PDU Set, is the same, it can be considered that the first PDU Sets in the three processes are the same first PDU Set.

[0186] Of course, the data packets of the first PDU Set sent by the user plane function network element to the access network device carry the first PDU Set information. Among them, the first PDU Set information is used for the access network device to determine which data packets in the QoS flow belong to the first PDU Set. Or rather, the first PDU Set information is used for the user plane function network element to send the first PDU Set to the access network device. There is a difference between the first information and the first PDU Set information in the embodiments of the present application. Or rather, the functions of the first information and the first PDU Set information are different. The first information is used for the first terminal device to send the first PDU Set to the second terminal device.

[0187] The embodiments of the present application list the information that the first information may include here. The following embodiments will introduce each piece of information in detail in the corresponding steps.

[0188] The first information may include: the sequence number information of the first PDU Set, the sequence number information of each data packet in the first PDU Set, the importance information of the first PDU Set, the indication information of the last data packet in the first PDU Set, the first delay, the second indication information, etc. Among them, the above various possible included information is determined by the access network device and added to at least one data packet of the first PDU Set.

[0189] S740. The first terminal device processes the data packets of the first PDU Set according to the first information.

[0190] In an embodiment of the present application, the first terminal device processes the data packets of the first PDU Set according to the first information, which may include: the first terminal device determines, according to the first information, that one or more data packets received from the access network device belong to the first PDU Set; or, the first terminal device processes the data packets of the first PDU Set according to the first information may further include: the first terminal device determines, according to the first information, whether to send the data packets of the first PDU Set to the second terminal device. Or, the first terminal device processes the data packets of the first PDU Set according to the first information may include: the first terminal device first determines, according to the first information, that one or more data packets received from the access network device belong to the first PDU Set, and then determines, according to the first information, whether to send the data packets belonging to the first PDU Set to the second terminal device. The following embodiments will be introduced separately.

[0191] Optionally, the first information includes at least one of the following: the sequence number information of the first PDU Set, the sequence number information of each data packet in the first PDU Set, or the indication information of the last data packet in the first PDU Set.

[0192] In an embodiment of the present application, the first terminal device processes the data packets of the first PDU Set according to the first information, including: the first terminal device determines, according to at least one of the sequence number information of the first PDU Set, the sequence number information of each data packet in the first PDU Set, or the indication information of the last data packet in the first PDU Set, that one or more data packets received from the access network device belong to the first PDU Set. This solution can enable the first terminal device to send one or more data packets received and belonging to the first PDU Set to the second terminal device, thus preparing for the transmission at the PDU Set granularity.

[0193] Exemplarily, the first terminal device determines that the received data packet belongs to the first PDU Set according to the sequence number information of the first PDU Set included in the first information in the received data packet.

[0194] It should be noted that if the first terminal device also processes other PDU Sets when processing the first PDU Set, each data packet in the one or more data packets sent by the access network device to the first terminal device carries the sequence number information of the first PDU Set.

[0195] Exemplarily, the first terminal device determines that the received data packet belongs to the first PDU Set according to the indication information of the last data packet in the first PDU Set included in the first information in the received data packet, and this data packet is the last data packet in the first PDU Set. It should be noted that the first terminal device determines that the data packets before this data packet belong to the first PDU Set according to the indication information of the last data packet in the first PDU Set included in the data packets received from the access network device.

[0196] Alternatively, as a possible implementation, the first terminal device determines that one or more data packets received from the access network device belong to the first PDU Set according to other information. For example, the first terminal device determines that one or more data packets received from the access network device belong to the first PDU Set according to the fact that the only PDU Set it is currently processing is the first PDU Set.

[0197] It should be noted that in the description of the following embodiments, it is described that the first terminal device receives one or more data packets from the access network device as one or more data packets of the first PDU Set received by the first terminal device from the access network device.

[0198] In the embodiments of the present application, the first terminal device determines whether to send the data packets of the first PDU Set to the second terminal device according to the first information. It can be that the first terminal device sends the data packets of the first PDU Set to the second terminal device according to the first information, or the first terminal device sends the data packets of the first PDU Set to the second terminal device according to the first information. Alternatively, before the first terminal device sends or does not send the data packets of the first PDU Set to the second terminal device according to the first information, the first terminal device first determines whether to send the data packets of the first PDU Set to the second terminal device according to the first information, and the embodiments of the present application do not limit this.

[0199] In the embodiments of the present application, the first terminal device sending the data packets of the first PDU Set to the second terminal device can be that the first terminal device sequentially sends the data packets of the first PDU Set to the second terminal device. Generally speaking, not all the data packets of the first PDU Set are sent instantaneously. The first terminal device not sending the data packets of the first PDU Set to the second terminal device can be that the first terminal device does not send any data packet of the first PDU Set to the second terminal device, or it can be that after the first terminal device sends one or more data packets of the first PDU Set to the second terminal device, it does not send the data packets of the first PDU Set that have not been sent to the second terminal to the second terminal device.

[0200] Optionally, the first information includes a first time delay. In the embodiments of the present application, the first time delay is used to indicate the transmission time delay budget of the first PDU Set from the first terminal device to the second terminal device, that is, the upper limit of the transmission time delay required from the moment when the first data packet of the first PDU Set is received by the first terminal device to the moment when the first PDU Set is sent to the second terminal device.

[0201] In the embodiments of the present application, the first time delay is determined according to the time when the access network device sends the first data packet of the first PDU Set to the first terminal device and the PSDB of the first PDU Set. The PSDB of the first PDU Set is used to characterize the transmission time delay budget of the first PDU Set. For the description of the PSDB of the first PDU Set, reference can be made to the relevant description in Related Art 4, which will not be elaborated here. This solution enables the access network device to determine the first time delay according to the sending time of the first PDU Set.

[0202] Exemplarily, the moment when the access network device receives the first data packet of the first PDU Set from the user plane function network element is t0, the moment when the access network device starts to send the first data packet of the first PDU Set to the first terminal device is t1, and the PSDB of the first PDU Set is t. Then the first time delay is t - (t1 - t0), where the PSDB of this first PDU Set is the RAN device PSDB introduced in Related Art 4 at this time.

[0203] In a possible implementation, the first terminal device processes the data packets of the first PDU Set according to the first information, including: the first terminal device determines whether to send the data packets of the first PDU Set to the second terminal device according to the first information. Further, when one or more data packets of the first PDU Set received by the first terminal device from the access network device meet the first time delay, the first terminal device sends the data packets of the first PDU Set to the second terminal device, that is, when sending one or more data packets of the first PDU Set, it is necessary to ensure that one or more data packets of the first PDU Set can be sent to the second terminal device within the first time delay.

[0204] In the embodiments of the present application, that one or more data packets of the first PDU Set received by the first terminal device from the access network device meet the first time delay may mean that there is still a remaining transmission time delay budget within the first time delay to ensure that the first terminal device can send one or more PDU Sets of the first PDU Set received from the access network device to the second terminal device.

[0205] Exemplarily, the first time delay is 20 ms, the first PDU Set includes 20 data packets, the transmission time delay budget for each data packet in the first PDU Set from the first terminal device to the second terminal device is 10 ms, the one or more data packets received by the first terminal device from the access network device are data packet 1 - data packet 10, the data packets simultaneously sent by the first terminal device to the second terminal device are data packet 1 - data packet 5, that is, the time delay already spent for the first terminal device to send data packet 1 - data packet 5 to the second terminal device is 10 ms, 10 ms remains for the first time delay, and the first terminal device determines to send data packet 6 - data packet 10 to the second terminal device according to the time delay budget of 10 ms for the remaining data packet 6 - data packet 10 (greater than or equal to the time delay budget of data packet 6 - data packet 10, that is, 10 ms).

[0206] Optionally, if there is no remaining transmission time delay budget within the first time delay, the first terminal device does not send the data packets that have not been sent among the one or more data packets received from the access network device to the second terminal device.

[0207] Optionally, the access network device adds the first time delay to the first packet or each data packet of the first PDU Set sent to the first terminal device. The first packet or each data packet received by the first terminal device from the access network device carries the first time delay. The first terminal device determines whether to send the data packets that have not been sent among the one or more data packets received from the access network device to the second terminal device according to the first time delay and the remaining transmission time delay budget within the current first time delay (for example, the second data packet of the first PDU Set received by the first terminal device carries the first time delay. The first terminal device determines the remaining transmission time delay budget within the current first time delay according to the time delay for sending the first packet of the first PDU Set to the second terminal device, and sends the second data packet of the first PDU Set to the second terminal device according to the remaining transmission time delay budget).

[0208] Optionally, the access network device adds an updated first delay during the process of sending one or more data packets of the first PDU Set to the first terminal device, that is, during the transmission of one or more data packets of the first PDU Set, the first delay may change; the first terminal device receives the first delay carried in the data packet from the access network device, and the first terminal device sends one or more data packets in the first PDU Set received from the access network device to the second terminal device according to the first delay. Specifically, the first delay starts to be calculated from the moment the data packet carrying the first delay is received, and it is necessary to ensure that the subsequent data packet in the first PDU Set is transmitted to the second terminal device side within the first delay. Alternatively, the above updated first delay may also be referred to as the remaining delay budget within the first delay, that is, the first information includes the remaining transmission delay budget within the first delay. For example, the access network device adds the first delay in the first packet of the first PDU Set sent to the first terminal device, and the access network device adds the remaining transmission delay budget within the first delay in the other data packets except the first packet sent to the first terminal device. The first terminal device sends or does not send the data packet to the second terminal device according to the remaining transmission delay budget within the first delay carried in the data packet received from the access network device, that is, the access network device determines the remaining transmission delay budget within the first delay and adds the remaining transmission delay budget within the first delay to the data packet, so that the access network device sends or does not send the data packet to the second terminal device according to the remaining transmission delay budget within the first delay carried in the data packet.

[0209] Optionally, the first information includes the transmission delay budget of each data packet in the first PDU Set determined by the first delay, and the transmission delay budget of each data packet is the transmission delay budget of the data packet from the first terminal device to the second terminal device. For example, the first delay is 20 ms, the first PDU Set includes 20 data packets, and the transmission delay budget of each data packet in the first PDU Set is 9 ms.

[0210] The following introduces two scenarios in which the access network device determines whether to send the data packets of the first PDUSet to the first terminal device according to the packet loss situation.

[0211] Case 1:

[0212] For scenario 1 or scenario 2 of the PDU Set processing in related art 6, if packet loss occurs during the process of the access network device sending the data packets of the first PDU Set to the first terminal device, the access network device determines not to send the data packets of the first PDU Set to the first terminal device. If no packet loss occurs during the process of the access network device sending the data packets of the first PDU Set to the first terminal device, the access network device determines to send the data packets of the first PDU Set to the first terminal device.

[0213] Scenario 2:

[0214] For the third processing scenario of the PDU Set in Related Art 6, if the cumulative number of packet losses during the process of the access network device sending the data packet of the first PDU Set to the first terminal device is greater than the first threshold, the access network device determines not to send the data packet of the first PDU Set to the first terminal device.

[0215] If the cumulative number of packet losses during the process of the access network device sending the data packet of the first PDU Set to the first terminal device is less than or equal to the first threshold, the access network device determines to send the data packet of the first PDU Set to the first terminal device. Alternatively, during the process of the access network device sending the first PDU Set to the first terminal device, it is necessary to ensure that the number of packet losses during the transmission of the data packet of the first PDU Set is within the range of the first threshold.

[0216] In the above Scenario 2, optionally, the first threshold is the maximum number of redundant packets of the first PDU Set configured by the session management function network element, or the first threshold is the maximum number of tolerable packet losses of the first PDU Set.

[0217] It should be noted that the access network device does not perceive whether packet losses occur during the process of the first terminal device sending the first PDUSet to the second terminal device.

[0218] In the embodiments of this application, the access network device not sending the data packet of the first PDU Set to the first terminal device may be that the access network device does not send the data packets that have not been sent or have not been successfully sent in the first PDU Set to the first terminal device; the access network device sending the data packet of the first PDU Set to the first terminal device may be that the access network device sends the data packets that have not been sent or have not been successfully sent in the first PDU Set to the first terminal device. The following separately introduces two scenarios in which the first terminal device determines whether to send the data packet of the first PDU Set to the second terminal device according to the packet loss situation. Optionally, whether the access network device sends the data packet of the first PDU Set to the first terminal device affects whether the first terminal device sends the data packet of the first PDU Set to the second terminal device.

[0219] Scenario 3:

[0220] For the first processing scenario or the second processing scenario of the PDU Set in the related art 6, if packet loss occurs during the process of the first terminal device sending the data packet of the first PDU Set to the second terminal device, or packet loss occurs during the process of the access network device sending the data packet of the first PDU Set to the first terminal device, the first terminal device determines not to send the data packet of the first PDU Set to the second terminal device.

[0221] It should be noted that for the above-mentioned first case, since the access network device does not send the next data packet in the first PDU Set after the packet loss, the access network device cannot notify the first terminal device of the packet loss through the data packet. In other words, the first terminal device does not sense whether packet loss occurs during the process of the access network device sending the data packet of the first PDU Set to the first terminal device. In this scenario, the first terminal device can determine that packet loss occurs during the process of the access network device sending the first PDU Set to the first terminal device based on the fact that it does not receive the data packet of the first PDU Set from the access network device subsequently. Alternatively, the access network device can create an empty data packet and send it to the first terminal device. The empty data packet carries indication information, where the indication information is used to indicate that the first terminal device does not send the data packet of the first PDU Set to the second terminal device, or the indication information is used to indicate that packet loss occurs during the process of the access network device sending the first PDU Set to the first terminal device. Furthermore, the first terminal device can determine that packet loss occurs during the process of the access network device sending the data packet of the first PDU Set to the first terminal device based on the indication information. Optionally, the indication information carries the identifier of the first PDU Set, such as the sequence number information of the PDU Set.

[0222] If no packet loss occurs during the process of the first terminal device sending the first PDU Set to the second terminal device, and no packet loss occurs during the process of the access network device sending the data packet of the first PDU Set to the first terminal device, the first terminal device determines to send the data packet of the first PDU Set to the second terminal device.

[0223] It should be noted that for the above-mentioned first case, the first terminal device can determine that no packet loss occurs during the process of the access network device sending the data packet of the first PDU Set to the first terminal device based on the fact that it can always receive the data packet of the first PDU Set from the access network device. It should be noted that the embodiments of the present application are described based on the access network device sending information (such as the following second indication information) to the first terminal device through data packets. The case where the access network device sends information to the first terminal device through control information is not elaborated in the embodiments of the present application.

[0224] Case 4:

[0225] For the third processing scenario of the PDU Set in Related Art 6, if the first terminal device determines that the sum of the number of packet losses that occur during the process of the first terminal device sending the data packet of the first PDU Set to the second terminal device and the number of packet losses that occur during the process of the access network device sending the data packet of the first PDU Set to the first terminal device is greater than the first threshold, then the first terminal device determines not to send the data packet of the first PDU Set to the second terminal device. Among them, packet loss may not occur during the process of the access network device sending the data packet of the first PDU Set to the first terminal device, and packet loss may not occur during the process of the first terminal device sending the data packet of the first PDU Set to the second terminal device, then correspondingly, it can be considered that the number of packet losses that occur is 0.

[0226] If the first terminal device determines that the sum of the number of packet losses that occur during the process of the first terminal device sending the data packet of the first PDU Set to the second terminal device and the number of packet losses that occur during the process of the access network device sending the data packet of the first PDU Set to the first terminal device is less than or equal to the first threshold, then the first terminal device determines to send the data packet of the first PDU Set to the second terminal device.

[0227] In the embodiments of the present application, the first terminal device not sending the data packet of the first PDU Set to the second terminal device may be that the first terminal device does not send the data packets that have not been sent or have not been successfully sent in the first PDU Set to the second terminal device; the first terminal device sending the data packet of the first PDU Set to the second terminal device may be that the first terminal device sends the data packets that have not been sent or have not been successfully sent in the first PDU Set to the second terminal device.

[0228] Optionally, as Figure 7 shown, the communication method provided by the embodiments of the present application further includes:

[0229] S750, the access network device sends second indication information to the first terminal device. Correspondingly, the first terminal device receives the second indication information from the access network device.

[0230] In the embodiments of the present application, the second indication information is used to indicate that packet loss occurs during the process of the access network device sending the data packet of the first PDU Set to the first terminal device.

[0231] In the embodiments of the present application, the access network device sends the second indication information to the first terminal device through a data packet. Exemplarily, for the corresponding situation four, the access network device adds the second indication information to a data packet after the data packet in which packet loss occurs in the data packets sent to the first terminal device. Optionally, the first information includes the second indication information; optionally, the second indication information is separate information in the data packet, and the embodiments of the present application do not limit this.

[0232] Alternatively, by way of example, corresponding to Case 3, the access network device creates an empty data packet, and the access network device sends the second indication information to the first terminal device through the empty data packet. This is not elaborated in the embodiments of the present application. Steps S750 and S760 mainly focus on Case 4 for description.

[0233] S760. The first terminal device determines not to send the data packets of the first PDU Set to the second terminal device according to the second indication information.

[0234] In the embodiments of the present application, the first terminal device determines not to send the data packets of the first PDU Set to the second terminal device according to the second indication information, which may be that the first terminal device does not send the data packets of the first PDU Set to the second terminal device according to the second indication information. Alternatively, in the embodiments of the present application, before the first terminal device does not send the data packets of the first PDU Set to the second terminal device according to the second indication information, the first terminal device first determines not to send the data packets of the first PDU Set to the second terminal device according to the second indication information.

[0235] In the embodiments of the present application, the first terminal device determines not to send the data packets of the first PDU Set to the second terminal device according to the second indication information, which may be that the first terminal device determines not to send the unsent data packets in the first PDU Set to the second terminal device according to the second indication information. This solution can enable the first terminal device to determine not to send the unsent data packets in the first PDU Set to the second terminal device according to the second indication information, and avoid wasting transmission resources caused by still sending the data packets of the first PDU Set to the second terminal device in the case of packet loss resulting in the first PDU Set being unable to be correctly decoded.

[0236] In a possible implementation manner, the second indication information is further used to indicate the second packet loss number in the first PDU Set, and the second packet loss number is the number of data packets that have been lost during the process of the access network device sending the data packets of the first PDU Set to the first terminal device determined by the access network device.

[0237] Optionally, every time a packet loss occurs during the process of the access network device sending the data packets of the first PDU Set to the first terminal device, the access network device sends an updated second packet loss count to the terminal device. For example, when the first packet loss occurs during the process of the access network device sending the data packets of the first PDU Set to the first terminal device, the second packet loss count indicated by the second indication information is 1. When the second packet loss occurs during the process of the access network device sending the data packets of the first PDU Set to the first terminal device, the second packet loss count indicated by the second indication information is 2, and so on. That is, the second packet loss count indicated by the second indication information is notified to the first terminal device in an incremental form, which will not be elaborated here.

[0238] Optionally, every time n packet losses occur during the process of the access network device sending the data packets of the first PDU Set to the first terminal device, the access network device sends an updated second packet loss count to the terminal device. For example, when the 5th packet loss occurs during the process of the access network device sending the data packets of the first PDU Set to the first terminal device, the access network device sends the second indication information to the first terminal device, and the second packet loss count indicated by the second indication information is 5. When the 10th packet loss occurs during the process of the access network device sending the data packets of the first PDU Set to the first terminal device, the access network device sends the second indication information to the first terminal device, and the second packet loss count indicated by the second indication information is 10, and so on, which will not be elaborated here.

[0239] In a possible implementation, the second indication information is further used to indicate a first difference, where the first difference is the difference between the first threshold and the second packet loss count. Here, the first difference is the number of remaining redundant data packets within the first threshold or the upper limit of the redundant data packets for transmitting the first PDU Set. The description of the update of the first difference can refer to the description of the updated second packet loss count above. For example, the first difference can be updated every time a packet loss occurs, or the first difference can be updated every time n packet losses occur, which will not be elaborated here.

[0240] In a possible implementation, the second indication information is further used to indicate a first redundant packet ratio, where the first redundant packet ratio is the ratio of the first difference to the number of data packets in the first PDU Set that the first terminal device has not yet sent to the second terminal device. According to the description in the above possible implementation, the second indication information is used to indicate the updated first redundant packet ratio, and the first terminal device sends the first PDU Set to the second terminal device according to the updated first redundant ratio, which can ensure that during the transmission of the first PDU Set, the number of packet losses is within the range of the first redundant ratio. Here, the update of the first redundant packet ratio can refer to the description of the updated first difference above. For example, the first redundant packet ratio can be updated every time a packet loss occurs, or the first redundant packet ratio can be updated every time n packet losses occur, which will not be elaborated here.

[0241] In the embodiment of the present application, the first terminal device determines not to send the data packets of the first PDU Set to the second terminal device according to the second indication information in the above several possible implementation manners.

[0242] Alternatively, as a possible implementation manner, the policy control function network element or the session management function network element may determine a second threshold and a third threshold according to the information provided by the application function network element or pre-configured information. Wherein, the second threshold is the maximum number of redundant packets corresponding to the first PDU Set from the access network device to the first terminal device, and the third threshold is the maximum number of redundant packets corresponding to the first PDU Set from the first terminal device to the second terminal device. Furthermore, the access network device sends the data packets of the first PDU Set to the first terminal device based on the second threshold, so as to ensure that the number or proportion of lost packets during the process of the access network device sending the data packets of the first PDU Set to the first terminal device is within the range of the second threshold. Or, the access network device determines not to send the data packets of the first PDU Set to the first terminal device according to the number of lost packets during the process of the access network device sending the data packets of the first PDU Set to the first terminal device being greater than the second threshold; Similarly, the first terminal device sends the data packets of the first PDU Set to the second terminal device based on the third threshold, so as to ensure that the number or proportion of lost packets during the process of the first terminal device sending the data packets of the first PDU Set to the second terminal device is within the range of the third threshold. Or, the first terminal device determines not to send the data packets of the first PDU Set to the second terminal device according to the number of lost packets during the process of the first terminal device sending the data packets of the first PDU Set to the second terminal device being greater than the third threshold.

[0243] Optionally, Figure 7 The above embodiment is illustrated by taking the case where the second indication information is not carried in the first information. Of course, as described above, the second indication information may also be carried in the first information. At this time, the above steps S750 and S760 are not executed. Step S740 is that the first terminal device processes the data packets of the first PDU Set according to the first information, including: the first terminal device determines whether to send the data packets of the first PDU Set to the second terminal device according to the first information. Further, the first terminal device determines not to send the data packets of the first PDU Set to the second terminal device according to the second indication information. The relevant description can refer to the description of step S760 and will not be elaborated here.

[0244] In a possible implementation manner, S760 specifically includes:

[0245] S761, the first terminal device determines the current cumulative first packet loss number according to the number of received second indication information.

[0246] In the embodiment of the present application, the first packet loss count includes the number of packet losses that occur during the process of the access network device sending the data packets of the first PDU Set to the first terminal device, and / or the number of packet losses that occur during the process of the first terminal device sending the data packets of the first PDU Set to the second terminal device.

[0247] It should be noted that in S761, the first terminal device determines the first packet loss count, and the second packet loss count indicated by the second indication information in the above S750 is determined by the access network device.

[0248] S762. When the first packet loss count is greater than the first threshold, the first terminal device determines not to send the data packets of the first PDU Set to the second terminal device.

[0249] In a possible implementation, the first packet loss count is 1 greater than the first threshold, and the first terminal device determines not to send the data packets of the first PDU Set to the second terminal device.

[0250] For example, the number of the second indication information received by the first terminal device is 5, the number of packet losses that occur during the process of the first terminal device sending the data packets of the first PDU Set to the first terminal device is 5, the first threshold is 9, and the first terminal device determines not to send the data packets of the first PDU Set to the second terminal device according to the first packet loss count of 10, which is greater than the first threshold of 9. This solution enables the first terminal device to determine not to send the data packets in the first PDU Set that have not been sent to the second terminal device according to the first packet loss count of the cumulative packet losses exceeding the first threshold, avoiding the waste of transmission resources caused by still sending the data packets of the first PDU Set to the second terminal device when the first packet loss count of the packet losses exceeds the first threshold and the first PDU Set cannot be correctly decoded.

[0251] Alternatively, as a possible implementation, packet losses occur during the process of the access network device sending the data packets of the first PDU Set to the first terminal device, and the second indication information is not sent to the first terminal device. The first terminal device can determine that packet losses occur during the process of the access network device sending the data packets of the first PDU Set to the first terminal device according to the discontinuous sequence numbers of the multiple data packets of the first PDU Set received from the access network device. Further, the first terminal device determines the currently cumulative first packet loss count according to the number of discontinuous sequence numbers of the multiple data packets received from the access network device. Then, when the first packet loss count is greater than the first threshold, the first terminal device determines not to send the data packets of the first PDU Set to the second terminal device. This implementation is based on the first information including the sequence number information of each data packet of the first PDU Set.

[0252] It should be noted that in the embodiments of the present application, for each data packet carrying the first information among one or more data packets of the first PDU Set sent by the access network device to the first terminal device, the carried first information may be different, so that the solutions in the above possible implementation manners can be implemented. For example, the first delay is carried in the first packet of the first PDU Set sent by the access network device to the first terminal device, or the remaining delay budget within the first delay is carried in each data packet other than the first packet of the first PDU Set sent by the access network device to the first terminal device, or the sequence number information of the data packet is carried in each data packet of the first PDU Set sent by the access network device to the first terminal device, or the sequence number information of the first PDU Set is carried in each data packet of the first PDU Set sent by the access network device to the first terminal device, or the indication information of the last data packet of the first PDU Set is carried in the last data packet of the first PDU Set sent by the access network device to the first terminal device. The embodiments of the present application do not limit this.

[0253] For the above Figure 7 In a possible implementation manner of the communication method shown above, although not shown, the communication method provided by the embodiments of the present application further includes:

[0254] S770. The access network device determines the first information according to the transmission status of the data packets of the first PDU Set sent to the first terminal device.

[0255] For example, when the first information includes the second indication information, the access network device determines the first information according to the packet loss that occurs during the process of sending the first PDU Set to the first terminal device; and for another example, when the first information includes the remaining transmission delay budget within the first delay, the access network device determines the first information according to the remaining transmission delay budget within the first delay during the process of sending the data packets of the first PDU Set to the first terminal device. It should be understood that the first information determined by the access network device is the first information carried in the data packets of the first PDU Set that the access network device has not sent to the first terminal device, that is, the access network device determines the first information carried in the data packets of the first PDU Set that the access network device has not sent to the first terminal device according to the transmission status of the data packets of the first PDU Set that have been sent to the first terminal device. Other examples of the access network device according to the transmission status of the data packets of the first PDU Set sent to the first terminal device can refer to the descriptions in the various corresponding possible implementation manners in the above embodiments, and will not be elaborated here.

[0256] In the communication method provided by an embodiment of this application, an access network device adds first information to at least one data packet among one or more data packets of a first PDU Set sent to a first terminal device according to first indication information received from a session management function network element, indicating that the access network device adds the first information to the first PDU Set. This enables the first terminal device to determine whether to send data packets of the first PDU Set to a second terminal device according to the first information carried in at least one data packet among one or more data packets of the first PDU Set received from the access network device. This solution enables an intermediate transmission node in a cascaded scenario, that is, the first terminal device, to obtain the transmission status of the first PDU Set and accordingly perform the transmission of the first PDU Set according to the first information.

[0257] Figure 8 It is a schematic diagram of another example of the communication method provided by an embodiment of this application. This method can be applied to a communication system as shown in Figure 4 The method will be described by taking the interaction of a user plane function network element, a source access network device, a target access network device, and a terminal device as an example. Of course, the entity that performs the actions of the user plane function network element in this method can also be a device / module in the user plane function network element, such as a chip, a processor, a processing unit, etc. in the user plane function network element; the entity that performs the actions of the source access network device in this method can also be a device / module in the source access network device, such as a chip, a processor, a processing unit, etc. in the source access network device; the entity that performs the actions of the target access network device in this method can also be a device / module in the target access network device, such as a chip, a processor, a processing unit, etc. in the target access network device; the entity that performs the actions of the terminal device in this method can also be a device / module in the terminal device, such as a chip, a processor, a processing unit, etc. in the terminal device. Embodiments of this application do not make specific limitations in this regard. In an embodiment of this application, the processing performed by a single execution entity (for example, the user plane function network element, the source access network device, the target access network device, and the terminal device) can also be divided into being performed by multiple execution entities, and these execution entities can be logically and / or physically separated. Exemplarily, as described in Figure 8 The method 800 includes:

[0258] S810, the user plane function network element sends a first PDU Set to the source access network device. Correspondingly, the source access network device receives the first PDU Set from the user plane function network element.

[0259] In an embodiment of this application, the first PDU Set information is carried in the first PDU Set sent by the user plane function network element to the source access network device. For the first PDU Set information, reference can be made to the relevant description in Related Art 4, and details are not described herein again.

[0260] In an embodiment of the present application, the user plane function network element sending a first PDU Set to the source access network device may be the data packet of the first PDU Set sent by the user plane function network element to the source access network device. For the description of the data packet of the first PDU Set sent by the user plane function network element to the source access network device, reference may be made to the relevant description of one or more data packets of the first PDU Set sent by the user plane function network element S720 to the access network device, and the embodiments of the present application will not describe it in detail.

[0261] S820, the source access network device sends some data packets of the first PDU Set to the terminal device. Correspondingly, the terminal device receives some data packets of the first PDU Set from the source access network device.

[0262] In an embodiment of the present application, some data packets of the first PDU Set sent by the source access network device to the terminal device are not the same as some data packets of the first PDU Set received by the terminal device from the source access network device. For the relevant description that some data packets of the first PDU Set sent by the source access network device to the terminal device are not the same as some data packets of the first PDU Set received by the terminal device from the source access network device, reference may be made to the relevant description in S720 that one or more data packets of the first PDU Set sent by the user plane function network element to the access network device are not the same as one or more data packets of the first PDU Set received by the access network device from the network element, and details will not be described here.

[0263] It should be noted that some data packets of the first PDU Set sent by the source access network device to the terminal device include data packets that have been transmitted and data packets that are being transmitted to the terminal device. Among them, the data packets that have been transmitted include at least one of the data packets received by the terminal device or the data packets that have been lost. Among them, the source access network device may determine that a data packet is lost according to the method described in the above related art 5.

[0264] S830, in the case where the terminal device switches to the target access network device, the source access network device sends the data packets in the first PDU Set that have not been transmitted to the target access network device. Correspondingly, the target access network device receives one or more data packets from the source access network device.

[0265] In a possible implementation, the data packets in the first PDU Set that have not been transmitted sent by the source access network device to the target access network also include at least one of the data packets that the source access network device fails to send to the terminal device and some data packets that the source access network device is sending to the terminal device, so as to improve the transmission success rate of the first PDU Set, which is not limited here.

[0266] In a possible implementation, if the packet loss situation of the packets that have been transmitted in a part of the first PDU Set sent by the source access network device to the terminal device meets the first condition, the source access network device sends the packets in the first PDU Set that have not been transmitted to the target access network device. In this solution, when the source access network device determines that the packets that have been transmitted in a part of the first PDU Set currently sent to the terminal device can ensure the correct decoding of the first PDU Set, it sends the packets in the first PDU Set that have not been transmitted to the target access network device, avoiding the waste of transmission resources caused by still sending the packets in the first PDU Set that have not been transmitted to the target access network device when the first PDU Set cannot be correctly decoded.

[0267] Optionally, the first condition is that no packet loss occurs. In the embodiments of the present application, if packet loss occurs in the packets that have been transmitted in a part of the first PDU Set sent by the source access network device to the terminal device, it will cause the first PDU Set to be unable to be correctly decoded as described in Scenario 1 and Scenario 2 in Related Art 6. Then, when no packet loss occurs, the source access network device sends the packets in the first PDU Set that have not been transmitted to the target access network device. In this solution, the source access network device sends the packets in the first PDU Set that have not been transmitted to the target access network device only when it determines that no packet loss occurs in the packets that have been transmitted in a part of the first PDU Set currently sent to the terminal device. It can send the packets in the first PDU Set that have not been transmitted to the target access network device when it can ensure the correct decoding of the first PDU Set, avoiding the waste of transmission resources caused by still sending the packets in the first PDU Set that have not been transmitted to the target access network device when the first PDU Set cannot be correctly decoded.

[0268] Optionally, the first condition is that the number of lost packets is less than or equal to the number of redundant data packets corresponding to the first PDU Set. In the embodiments of the present application, if the number of lost packets of the data packets that have been transmitted among the partial data packets of the first PDU Set sent by the source access network device to the terminal device is greater than the maximum number of redundant packets of the first PDU Set, it will cause the first PDU Set to be unable to be correctly decoded as described in Scenario 3 of Related Art 6. Then, when the number of lost packets is less than or equal to the maximum number of redundant packets of the first PDU Set, the source access network device sends the data packets that have not been transmitted in the first PDU Set to the target access network device. Among them, the maximum number of redundant packets of the first PDU Set is configured by the session management function network element for the first PDU Set. In this solution, the source access network device sends the data packets that have not been transmitted in the first PDU Set to the target access network device only when it determines that the number of lost packets of the data packets that have been transmitted among the partial data packets of the first PDU Set currently sent to the terminal device is less than or equal to the number of redundant data packets corresponding to the first PDU Set. This can ensure that the data packets that have not been transmitted in the first PDU Set are sent to the target access network device under the condition that the first PDU Set can be correctly decoded, and avoid wasting transmission resources by still sending the data packets that have not been transmitted in the first PDU Set to the target access network device when the first PDU Set cannot be correctly decoded.

[0269] In the embodiments of the present application, the data packets that have not been transmitted in the first PDU Set sent by the source access network device to the destination access network device are the remaining data packets after the source access network device sends partial data packets of the first PDU Set to the terminal device before the terminal device switches to the target access network. For example, the first PDU Set includes 20 data packets. Before the terminal device switches to the target access network device, the data packets of the first PDU Set sent by the source access network device to the terminal device are Data Packet 1 - Data Packet 10. After the terminal device switches to the target access network device, the data packets that have not been transmitted in the first PDU Set are Data Packet 11 - Data Packet 20.

[0270] Similarly, the data packets that have not been transmitted in the first PDU Set sent by the source access network device to the target access network device are not equivalent to one or more data packets received by the target access network device from the source access network device. For details, refer to the description in S720 and will not be elaborated here.

[0271] In the embodiment of the present application, at least one data packet among the data packets not yet transmitted in the first PDU Set sent by the source access network device to the target access network device carries the first information, and at least one data packet among one or more data packets received by the target access network device from the source access network device carries the first information. Optionally, the at least one data packet carrying the first information is the first packet of the data packets not yet transmitted in the first PDU Set; or, optionally, the at least one data packet carrying the first information is each data packet among the data packets not yet transmitted in the first PDU Set; or, optionally, the at least one data packet carrying the first information is the first packet and some data packets among the data packets not yet transmitted in the first PDU Set. Among them, the manner in which at least one data packet among the data packets not yet transmitted in the first PDU Set sent by the source access network device to the target access network device carries the first information can refer to the description of the manner in which at least one data packet among one or more data packets of the first PDU Set sent by the access network device to the first terminal device in S730, which will not be elaborated here.

[0272] In the embodiment of the present application, the possible information included in the first information is enumerated here, and the following embodiments will introduce each information in detail in the corresponding steps.

[0273] The first information may include: the sequence number information of the first PDU Set, the sequence number information of each data packet in the first PDU Set, the importance information of the first PDU Set, the indication information of the last data packet in the first PDU Set, the first delay, the first redundancy packet ratio, etc. Among them, the above various possible information is determined by the source access network device and added to at least one data packet among the data packets not yet transmitted in the first PDU Set sent to the target access network device.

[0274] S840, the target access network device processes one or more data packets from the source access network device according to the first information.

[0275] In the embodiments of the present application, the target access network device processes one or more data packets from the source access network device according to the first information, which may include that the target access network device determines, according to the first information, that one or more data packets received from the source access network device belong to the first PDU Set. The target access network device processing the first PDU Set according to the first information may further include that the target access network device determines, according to the first information, whether to send one or more data packets of the first PDU Set from the source access network device to the terminal device. Alternatively, the target access network device processing one or more data packets from the source access network device according to the first information may include that the target access network device first determines, according to the first information, that one or more data packets received from the source access network device belong to the first PDU Set, and then determines, according to the first information, whether to send one or more data packets from the source access network device belonging to the first PDU Set to the terminal device. The following embodiments will be introduced separately.

[0276] Optionally, the first information includes at least one of the following: sequence number information of the first PDU Set, sequence number information of each data packet in the first PDU Set, or indication information of the last data packet in the first PDU Set.

[0277] In the embodiments of the present application, the target access network device processes one or more data packets from the source access network device according to the first information, including: the target access network device determines, according to at least one of the sequence number information of the first PDU Set, the sequence number information of each data packet in the first PDU Set, or the indication information of the last data packet in the first PDU Set, that one or more data packets received from the source access network device belong to the first PDU Set. This solution can enable the target access network device to send one or more data packets received and belonging to the first PDU Set to the terminal device, thereby implementing transmission processing at the PDU Set granularity.

[0278] In the embodiments of the present application, for the related description of the target access network device determining that one or more received data packets belong to the first PDU Set according to at least one of the sequence number information of the first PDU Set, the sequence number information of each data packet in the first PDU Set, or the indication information of the last data packet in the first PDU Set, reference may be made to the related description in S730 where the first terminal device determines that one or more received data packets belong to the first PDU Set according to at least one of the sequence number information of the first PDU Set, the sequence number information of each data packet in the first PDU Set, or the indication information of the last data packet in the first PDU Set, and details will not be elaborated here.

[0279] It should be noted that in the following embodiments, one or more data packets from the source access network device are described as one or more data packets of the first PDU Set from the source access network device.

[0280] In the embodiments of the present application, based on the first information, the target access network device determines whether to send one or more data packets from the source access network device to the terminal device. This may be that the target access network device sends one or more data packets from the source access network device to the terminal device according to the first information, or it may be that the target access network device does not send one or more data packets from the source access network device to the terminal device according to the first information. Alternatively, before the target access network device sends or does not send one or more data packets from the source access network device to the terminal device according to the first information, the target access network device first determines whether to send one or more data packets from the source access network device to the terminal device according to the first information.

[0281] In the embodiments of the present application, the first information is used to transmit the data packets in the first PDU Set that have not been transmitted. In other words, the first information is used for the target access network device to determine whether to send one or more of the data packets in the first PDU Set received from the source access network device that have not been transmitted to the terminal device.

[0282] It should be noted that for the sake of clear description, the data packets in the first PDU Set that have not been transmitted are only used to represent the remaining data packets after the source access network device sends a part of the data packets of the first PDU Set to the terminal device before the terminal device switches to the target access network. For the part of the data packets of the first PDU Set sent by the source access network device to the terminal device, in the following optional steps, the lost data packets or the data packets being transmitted in this part of the data packets, together with the data packets in the first PDU Set that have not been transmitted, are sent from the source access network device to the target access network device, and the target access network device re - sends them to the terminal device. In the embodiments of the present application, since this part of the data packets has been transmitted from the source access network device to the terminal device, this part of the data packets is not included in the scope of the data packets in the first PDU Set that have not been transmitted.

[0283] Optionally, the first information includes a first delay. The first delay is used to indicate the transmission delay budget of the first PDU Set from the first terminal device to the second terminal device, that is, the upper limit of the transmission delay required from the time the first terminal device receives the first data packet of the first PDU Set to the time it sends the first PDU Set to the second terminal device.

[0284] In the embodiments of the present application, the first time delay is determined according to the PSDB of the first PDU Set, including: the first time delay information is determined according to the PSDB of the first PDU Set and at least one of the following: the time when the source access network device receives the first data packet in the first PDU Set; the start time when the source access network device sends the data packets that have not been transmitted in the first PDU Set to the target access network device, and the link delay from the source access network device to the target access network device. It should be noted that the first PSDB is the RAN device PSDB in the above related art 4.

[0285] Exemplarily, the first time delay is determined according to the PSDB of the first PDU Set, the time when the source access network device receives the first data packet in the first PDU Set, and the start time when the source access network device sends the data packets that have not been transmitted in the first PDU Set to the target access network device. For example, the moment when the source access network device receives the first data packet of the first PDU Set from the user plane function network element is t', the start time when the source access network device sends the data packets of the first PDU Set to the target access network device is t", and the PSDB of the first PDU Set is t, then the first time delay is t - (t" - t').

[0286] Exemplarily, the first time delay is determined according to the PSDB of the first PDU Set, the time when the source access network device receives the first data packet in the first PDU Set, the start time when the source access network device sends the data packets that have not been transmitted in the first PDU Set to the target access network device, and the link delay from the source access network device to the target access network device. For example, the moment when the source access network device receives the first data packet of the first PDU Set from the user plane function network element is t', the start time when the source access network device sends the data packets of the first PDU Set to the target access network device is t", the link delay from the source access network device to the target access network device is t''', and the PSDB of the first PDU Set is t, then the first time delay is t - (t" - t') - t'''.

[0287] In a possible implementation, the target access network device processes one or more data packets of the first PDU Set from the source access network device according to the first information, including: the target access network device determines whether to send one or more data packets of the first PDU Set from the source access network device to the terminal device according to the first information. Further, when one or more data packets of the first PDU Set received by the target access network device from the source access network device meet the first delay, the target access network device sends the data packets that have not been transmitted in one or more data packets of the first PDU Set from the source access network device to the terminal device. Or, the target access network device needs to ensure that one or more data packets of the first PDU Set from the source access network device are sent to the terminal device within the first delay.

[0288] In the embodiments of this application, the description of one or more data packets of the first PDU Set received by the target access network device from the source access network device meeting the first delay can refer to the relevant description in S740 about one or more data packets received by the first terminal device from the access network device meeting the first delay, which will not be elaborated here.

[0289] Optionally, the first information further includes the remaining transmission delay budget within the first delay. The description of the remaining delay budget within the first delay can refer to the description of the remaining transmission delay budget within the first delay in S740, which will not be elaborated here.

[0290] Optionally, the first information includes the transmission delay budget for each data packet in one or more data packets from the source access network device determined by the first delay. The transmission delay budget for each data packet can refer to the transmission delay budget for each data packet in the first PDU Set determined by the first delay in S740, which will not be elaborated here.

[0291] It should be noted that the following description of redundant data packets corresponds to processing scenario three in related art 6. If it corresponds to processing scenario one or processing scenario two in related art 6, the target access network device can determine not to send the data packets that have not been transmitted in one or more data packets of the first PDU Set from the source access network device to the terminal device according to the packet loss occurring during the process of sending one or more data packets of the first PDU Set from the source access network device to the terminal device.

[0292] Optionally, the first information includes a first redundant packet ratio. The first redundant packet ratio is the ratio of the number of data packets included in the data packets that have not been transmitted in the first PDU Set to the number of redundant data packets corresponding to the data packets that have not been transmitted in the first PDU Set, or the first redundant packet ratio is the ratio of the redundant data packets in the data packets that have not been transmitted in the first PDU Set (that is, referring to the description of Related Art 6, the data packets that have not been transmitted in the first PDU Set include redundant data packets), or the first redundant packet ratio is the upper limit of tolerable packet loss in the data packets that have not been transmitted in the first PDU Set.

[0293] In the embodiment of the present application, the number of redundant data packets corresponding to the data packets that have not been transmitted in the first PDU Set is the difference between the maximum number of redundant data packets of the first PDU Set and the number of lost packets of the data packets that have been transmitted and lost among the partial data packets of the first PDU Set sent by the source access network device to the terminal device.

[0294] For example, the first PDU Set includes 40 data packets, the number of partial data packets of the first PDU Set sent by the source access network device to the terminal device is 20, then the data packets that have not been transmitted in the first PDU Set are 20, the number of lost packets of the data packets that have been transmitted and lost among the partial data packets of the first PDU Set sent by the source access network device to the terminal device is 5, the maximum number of redundant data packets of the first PDU Set is 10, then the number of redundant data packets corresponding to the data packets that have not been transmitted in the first PDU Set is 5, and the first redundant packet ratio is 5 / 20.

[0295] In the embodiment of the present application, the upper limit of tolerable packet loss in the data packets that have not been transmitted in the first PDU Set can be understood as that if the number of lost packets exceeds this upper limit of packet loss, the target access network device does not send the data packets that have not been transmitted in one or more data packets of the first PDU Set from the source access network device to the terminal device.

[0296] In a possible implementation, the target access network device processes one or more data packets from the source access network device according to the first information, including: the target access network device determines whether to send one or more data packets of the first PDU Set from the source access network device to the terminal device according to the first information. Further, first, the target access network device determines the first quantity of data packets that are lost during the process of sending one or more data packets of the first PDU Set from the source access network device to the terminal device; in the case where the first quantity is greater than the quantity of redundant data packets corresponding to the first redundancy packet ratio, the target access network device determines not to send the data packets that have not been transmitted among one or more data packets of the first PDU Set from the source access network device. This solution can avoid wasting transmission resources caused by still sending the data packets of the first PDU Set to the terminal device when the first quantity of lost data packets causes the first PDU Set to be unable to be correctly decoded.

[0297] Optionally, the first information includes a second redundant packet ratio. As a possible implementation, the source access network device may send to the target access network device the packets that have been lost among the packets that have been transmitted in the partial data packets of the first PDU Set sent by the source access network device to the terminal device in S830 above. Correspondingly, the source access network device determines the second redundant packet ratio, which is the ratio of the first threshold to the sum of the packets that have not been transmitted in the first PDU Set and the packets that have been lost and sent to the target access network device. That is, it can be understood that the source access network device sends the packets that have been lost to the target access network device for retransmission by the target access network device, which is equivalent to that the partial data packets of the first PDU Set sent by the source access network device to the terminal device have not been lost, and the current number of redundant data packets is still the first threshold. For example, if the number of packets that have not been transmitted in the first PDU Set is 20, the first threshold is 10, and the number of packets that have been lost among the packets that have been transmitted in the partial data packets sent by the source access network device to the terminal device and sent by the source access network device to the target access network device is 6, then the second redundant packet ratio is 10 / (20 + 6). The source access network device sending the packets that have been lost among the packets that have been transmitted in the partial data packets of the first PDU Set sent by the source access network device to the terminal device to the target access network device can increase the transmission success probability of the first PDU Set. Optionally, the first information includes a third redundant packet ratio. As a possible implementation, the source access network device may send to the target terminal device the data packets that are being transmitted by the source access network device to the terminal device. Correspondingly, the source access network device determines the third redundant packet ratio, which is the ratio of the number of redundant data packets corresponding to the packets that have not been transmitted in the first PDU Set to the sum of the packets that have not been transmitted in the first PDU Set and the data packets that are being transmitted by the source access network device to the terminal device. Optionally, the source access network device may stop transmitting the data packets that are being transmitted by the source access network device to the terminal device.

[0298] Optionally, although not shown, the communication method provided in the embodiments of the present application further includes:

[0299] S831. The source access network device determines the first information according to the transmission status of the data packets of the first PDU Set sent to the terminal device.

[0300] Exemplarily, when the transmission status of the data packets of the first PDU Set sent by the source access network device to the terminal device is packet loss, the first information is correspondingly determined to include the above first redundant packet ratio, which is described in the description of the first redundant packet ratio in the embodiments of the present application above and will not be elaborated here.

[0301] Optionally, as Figure 8As shown in the figure, the communication method provided by the embodiment of the present application further includes:

[0302] S850, the source access network device sends first indication information to the target access network device. Correspondingly, the target access network device receives the first indication information from the source access network device.

[0303] In the embodiment of the present application, the first indication information is used to indicate that at least one first data packet being transmitted to the terminal device through the source access network device in the first PDU Set is lost.

[0304] It should be noted that during the process of the source access network device sending the data packets in the first PDU Set that have not been transmitted to the target access network device, one or more data packets in the part of the data packets sent by the source access network device to the terminal device may also be in the process of transmission, and in this process, if a packet loss occurs, the source access network device can send the first indication information to the target access network device.

[0305] Optionally, the first indication information can be added to the GTP-U layer of the data packet sent by the source access network device to the target access network device. Exemplarily, the first indication information can include the identification information of the first PDU Set, such as the sequence number information of the first PDU Set; optionally, the first indication information is other control plane information, and the embodiment of the present application does not limit this.

[0306] In a possible implementation manner, corresponding to processing scenario one or processing scenario two in related art 6, the first data packet being transmitted to the terminal device through the source access network device in the first PDU Set is lost, and the target access network device determines not to send the data packets in the first PDU Set of the source access network device that have not been transmitted to the terminal device.

[0307] In another possible implementation manner, corresponding to processing scenario three in related art 6, the target access network device determines an updated first redundancy packet ratio according to the first indication information, and determines whether to send one or more data packets in the first PDU Set of the source access network device to the terminal device according to the updated first redundancy packet ratio. For example, the first redundancy packet ratio is 5 / 20, the target access network device receives the first indication information from the source access network device, and determines that the updated first redundancy packet ratio is (5 - 1) / 20. This example is based on the fact that the target access network device has not yet sent the first data packet in one or more data packets in the first PDU Set of the source access network device to the terminal device. If the target access network device has already sent at least one data packet in one or more data packets in the first PDU Set of the source access network device to the terminal device, then the value of 20 is correspondingly reduced.

[0308] In the above two possible implementation manners, when the source access network device discovers that at least one first data packet being transmitted by the source access network device to the terminal device is lost, the source access network device can notify the target access network device in a timely manner, so as to avoid waste of transmission resources caused by the target access network device still sending data packets of the first PDU Set to the terminal device when the first PDU Set cannot be correctly decoded due to the loss of at least one first data packet.

[0309] Optionally, the first indication information is further used to indicate the number of at least one first data packet for which packet loss occurs. For example, the first indication information is sent once every n packet losses. This solution can enable the target access network device to determine the number of at least one first data packet for which packet loss occurs.

[0310] Optionally, as Figure 8 shown, the communication method provided in the embodiments of the present application further includes:

[0311] S860, the source access network device sends at least one first data packet to the target access network device. Correspondingly, the target access network device receives at least one first data packet from the source access network device.

[0312] In the embodiments of the present application, the source access network device can send at least one first data packet to the target access network device, and the target access network device sends it to the terminal device, so as to avoid that the target access network device does not send one or more data packets of the first PDU Set from the source access network device to the terminal device due to the loss of at least one first data packet being transmitted by the source access network device in the first PDU Set, and increases the transmission success rate of the data packets that have not been transmitted in the first PDU Set from the target access network device to the terminal device.

[0313] In the communication method provided in the embodiments of the present application, the source access network device receives a first PDU Set from a user plane function network element and sends partial data packets of the first PDU Set to the terminal device. When the terminal device switches to the target access network device, the source access network device sends the data packets that have not been transmitted in the first PDU Set to the target access network device, where at least one data packet of the data packets that have not been transmitted in the first PDU Set carries first information, and the target access network device determines whether to send one or more data packets received from the source access network device to the terminal device according to the first information. This solution ensures the joint transmission of the source access network device and the target access network device for the first PDU Set in the handover scenario.

[0314] The above mainly introduced the solution provided by the embodiments of the present application from the perspective of the interaction among the session management function network element, the user plane function network element, the access network device, the first terminal device, and the second terminal device. Alternatively, the above mainly introduced the solution provided by the embodiments of the present application from the perspective of the interaction among the user plane function network element, the source access network device, the target access network device, and the terminal device. Correspondingly, the embodiments of the present application further provide a communication device, which is used to implement the above various methods. The communication device can be any device or network element in the above method embodiments, or a device including any of the above devices or network elements, or a component applicable to any of the above devices or network elements. It can be understood that, in order to implement the above functions, the communication device includes the corresponding hardware structure and / or software module for executing each function. Those skilled in the art should easily realize that, combining the units and algorithm steps of each example described in the embodiments disclosed herein, the present application can be implemented in the form of hardware or a combination of hardware and computer software. Whether a certain function is executed in the way of hardware or computer software driving hardware depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present application.

[0315] For example, Figure 9 is a schematic diagram of the communication device provided by the embodiments of the present application, where the communication device includes a transceiver module 910 and a processing module 920. The transceiver module 910, which can also be referred to as a transceiver unit, is used to implement the transceiver function. For example, it can be a transceiver circuit, a transceiver, a transceiver, or a communication interface.

[0316] Taking the communication device as the access network device in the above method embodiments (which can be a chip of the access network device, or a module of the access network device, or a device inside the access network device) as an example:

[0317] The transceiver module 910 is used to receive the first indication information from the session management function network element, and the first indication information is used to indicate the access network device to add the first information to the first PDU Set.

[0318] The transceiver module 910 is further used to receive one or more data packets of the first PDU Set from the user plane function network element.

[0319] The processing module 920 is used to add the first information to at least one of the one or more data packets of the first PDU Set from the user plane function network element.

[0320] The transceiver module 910 is further configured to send one or more data packets of the first PDU Set to the first terminal device. At least one of the one or more data packets of the first PDU Set sent to the first terminal device carries first information, where the first information is used for the first terminal device to process the data packets of the first PDU Set according to the first information when sending the first PDU Set to the second terminal device.

[0321] In a possible implementation, the processing module 920 is further configured to determine the first information according to the transmission status of the data packets of the first PDU Set sent to the first terminal device.

[0322] In a possible implementation, the first information includes at least one of the following: the sequence number information of the first PDU Set, the sequence number information of each data packet in the first PDU Set, or the indication information of the last data packet in the first PDU Set. Wherein, the first information is used for the first terminal device to process the data packets of the first PDU Set according to the first information when sending the first PDU Set to the second terminal device, including: at least one of the sequence number information of the first PDU Set, the sequence number information of each data packet in the first PDU Set, or the indication information of the last data packet in the first PDU Set is used for the first terminal device to determine that one or more data packets received from the transceiver module 910 belong to the first PDU Set.

[0323] In a possible implementation, the first information includes a first time delay, and the first time delay is the transmission time delay budget of the first PDU Set from the first terminal device to the second terminal device.

[0324] In a possible implementation, the first time delay is determined according to the time when the transceiver module 910 sends the first data packet of the first PDU Set to the first terminal device and the time delay budget PSDB of the first PDU Set, where the PSDB of the first PDU Set is used to represent the transmission time delay budget of the first PDU Set.

[0325] In the embodiments of the present application, the transceiver module 910 is further configured to send second indication information to the first terminal device, where the second indication information is used to indicate that packet loss occurs during the process of the access network device sending the data packets of the first PDU Set to the first terminal device.

[0326] Taking the communication device as the first terminal device in the above method embodiment (which may be a chip of the first terminal device, or a module of the first terminal device, or a device inside the first terminal device) as an example:

[0327] A transceiver module 910 is configured to receive one or more data packets from an access network device. Among them, the one or more data packets belong to a first PDU Set, and at least one of the one or more data packets carries first information.

[0328] A processing module 920 is configured to process the data packets of the first PDU Set according to the first information.

[0329] In a possible implementation, the first information is determined by the access network device according to the transmission status of the data packets of the first PDU Set sent to the transceiver module 910.

[0330] In a possible implementation, the first information includes at least one of the following: sequence number information of the first PDU Set, sequence number information of each data packet in the first PDU Set, or indication information of the last data packet in the first PDU Set. The processing module 920 is configured to process the data packets of the first PDU Set according to the first information, including: determining that one or more data packets received by the transceiver module 910 from the access network device belong to the first PDU Set according to at least one of the sequence number information of the first PDU Set, sequence number information of each data packet in the first PDU Set, or indication information of the last data packet in the first PDU Set.

[0331] In a possible implementation, the first information includes a first time delay, and the first time delay is the transmission time delay budget of the first PDU Set from the first terminal device to the second terminal device. The processing module 920 is configured to process the data packets of the first PDU Set according to the first information, including: when the processing module 920 determines that one or more data packets received from the access network device satisfy the first time delay, the transceiver module 910 sends the data packets of the first PDU Set to the second terminal device.

[0332] In a possible implementation, the first time delay is determined according to the time when the access network device sends the first data packet of the first PDU Set to the first terminal device and the time delay budget PSDB of the first PDU Set, and the PSDB of the first PDU Set is used to represent the transmission time delay budget of the first PDU Set.

[0333] In the embodiments of the present application, the transceiver module 910 is further configured to receive second indication information from the access network device, and the second indication information is used to indicate that packet loss occurs during the process of the access network device sending the data packets of the first PDU Set to the first terminal device.

[0334] The processing module 920 is further configured to determine not to send the data packets of the first PDU Set to the second terminal device according to the second indication information.

[0335] In the embodiment of the present application, the processing module 920 is further configured to determine not to send the data packets of the first PDU Set to the second terminal device according to the second indication information, including: the processing module 920 is further configured to determine the current cumulative number of first packet losses according to the number of received second indication information, and the first packet loss number includes the number of packet losses that occur during the process of the access network device sending the data packets of the first PDU Set to the transceiver module 910, and / or the number of packet losses that occur during the process of the transceiver module 910 sending the data packets of the first PDU Set to the second terminal device. In the case where the first packet loss number is greater than the first threshold, the processing module 920 determines not to send the data packets of the first PDU Set to the second terminal device.

[0336] Taking the communication device as the source access network device in the above method embodiment (which can be the chip of the source access network device, or the module of the source access network device, or the device inside the source access network device) as an example:

[0337] The transceiver module 910 is configured to receive the first PDU Set and send some data packets of the first PDU Set to the terminal device.

[0338] The processing module 920 is configured to add the first information to at least one of the data packets that have not been transmitted in the first PDU Set sent to the target access network device when the terminal device switches to the target access network device.

[0339] The transceiver module 910 is further configured to send the data packets that have not been transmitted in the first PDU Set to the target access network device when the terminal device switches to the target access network device. Among them, at least one of the data packets that have not been transmitted in the first PDU Set carries the first information, and the first information is used for the target access network device to process one or more data packets from the transceiver module 910 according to the first information when sending one or more data packets from the transceiver module 910 to the terminal device.

[0340] In a possible implementation manner, the processing module 920 is further configured to determine the first information according to the transmission status of the data packets of the first PDU Set sent to the terminal device.

[0341] In a possible implementation, the first information includes at least one of the following: the sequence number information of the first PDU Set, the sequence number information of each data packet in the first PDU Set, or the indication information of the last data packet in the first PDU Set. Wherein, when the target access network device sends one or more data packets from the source access network device to the terminal device, the first information is used to process the one or more data packets from the source access network device, including: at least one of the sequence number information of the first PDU Set, the sequence number information of each data packet in the first PDU Set, or the indication information of the last data packet in the first PDU Set is used for the target access network device to determine that one or more data packets received from the transceiver module 910 belong to the first PDU Set.

[0342] In a possible implementation, the first information includes a first delay, and the first delay is used to indicate the transmission delay budget of the data packets that have not been transmitted in the first PDU Set.

[0343] In a possible implementation, the first delay is determined according to the delay budget PSDB of the first PDU Set, and the PSDB of the first PDU Set is used to characterize the transmission delay budget of the first PDU Set.

[0344] In a possible implementation, the first delay is determined according to the PSDB of the first PDU Set, including: the first delay information is determined according to the PSDB of the first PDU Set and at least one of the following: the time when the transceiver module 910 receives the first data packet in the first PDU Set; the start time when the transceiver module 910 sends the data packets that have not been transmitted in the first PDU Set to the target access network device; or, the link delay from the communication device to the target access network device.

[0345] In a possible implementation, the first information includes a first redundancy packet ratio. Wherein, the first redundancy packet ratio is the ratio of the number of data packets included in the data packets that have not been transmitted in the first PDU Set to the number of redundant packets corresponding to the data packets that have not been transmitted in the first PDU Set, or the first redundancy packet ratio is the upper limit of tolerable packet loss in the data packets that have not been transmitted in the first PDU Set.

[0346] In the embodiments of the present application, the transceiver module 910 sends the data packets that have not been transmitted in the first PDU Set to the target access network device, including: if the packet loss situation of the data packets that have been transmitted in the partial data packets of the first PDU Set sent to the terminal device satisfies the first condition, the transceiver module 910 sends the data packets that have not been transmitted in the first PDU Set to the target access network device.

[0347] In a possible implementation, the first condition is that no packet loss occurs.

[0348] In a possible implementation, the first condition is that the number of lost packets is less than or equal to the number of redundant data packets corresponding to the first PDU Set.

[0349] In a possible implementation, the transceiver module 910 is further configured to send first indication information to the target access network device, where the first indication information is used to indicate that at least one first data packet being transmitted to the terminal device in the first PDU Set by the transceiver module 910 is lost.

[0350] In a possible implementation, the first indication information is further used to indicate the number of at least one first data packet for which packet loss occurs.

[0351] In a possible implementation, the transceiver module 910 is further configured to send at least one first data packet to the target access network device.

[0352] Taking the communication device as the target access network device in the above method embodiment (which may be a chip of the target access network device, or a module of the target access network device, or a device inside the target access network device) as an example:

[0353] The transceiver module 910 is configured to receive one or more data packets from the source access network device when the terminal device switches to the target access network device. Among them, the one or more data packets are data packets in the first PDU Set that have not been transmitted. At least one of the one or more data packets carries first information; the data packets in the first PDU Set that have not been transmitted are the remaining data packets after the source access network device sends some data packets of the first PDU Set to the terminal device.

[0354] The processing module 920 is configured to process one or more data packets from the source access network device according to the first information.

[0355] In the embodiment of the present application, the first information is determined by the source access network device according to the transmission status of the data packets in the first PDU Set sent to the terminal device.

[0356] In a possible implementation, the first information includes at least one of the following: the sequence number information of the first PDU Set, the sequence number information of each data packet in the first PDU Set, or the indication information of the last data packet in the first PDU Set. The processing module 920 processes one or more data packets from the source access network device according to the first information, including: the processing module 920 is used to determine that one or more data packets received by the transceiver module 910 from the source access network device belong to the first PDU Set according to at least one of the sequence number information of the first PDU Set, the sequence number information of each data packet in the first PDU Set, or the indication information of the last data packet in the first PDU Set.

[0357] In a possible implementation, the first information includes a first delay, and the first delay is used to indicate the transmission delay budget of the data packets not yet transmitted in the first PDU Set. The processing module 920 is used to process one or more data packets from the source access network device according to the first information, including: when one or more data packets received from the source access network device meet the first delay, the transceiver module 910 is used to send one or more data packets of the first PDU Set received from the source access network device to the terminal device.

[0358] In a possible implementation, the first delay is determined according to the delay budget PSDB of the first PDU Set, and the PSDB of the first PDU Set is used to characterize the transmission delay budget of the first PDU Set.

[0359] In a possible implementation, the first delay is determined according to the PSDB of the first PDU Set, including: the first delay information is determined according to the PSDB of the first PDU Set and at least one of the following: the time when the source access network device receives the first data packet in the first PDU Set; the start time when the source access network device sends the data packets not yet transmitted in the first PDU Set to the transceiver module 910; or, the link delay from the source access network device to the communication device.

[0360] In a possible implementation, the first information includes a first redundant packet ratio. The first redundant packet ratio is the ratio of the number of data packets included in the data packets that have not been transmitted in the first PDU Set to the number of redundant packets corresponding to the data packets that have not been transmitted in the first PDU Set, or the first redundant packet ratio is the upper limit of tolerable packet loss in the data packets that have not been transmitted in the first PDU Set. The processing module 920 processes one or more data packets from the source access network device according to the first information, including: the processing module 920 determines a first quantity of data packets that experience packet loss during the process of sending one or more data packets from the source access network device to the terminal device. In the case where the first quantity is greater than the number of redundant packets corresponding to the first redundant packet ratio, the processing module 920 is further configured to determine not to send the data packets that have not been transmitted in one or more data packets from the source access network device.

[0361] In a possible implementation, no packet loss occurs in some of the data packets of the first PDU Set sent by the source access network device to the terminal device.

[0362] In a possible implementation, the number of lost packets in some of the data packets of the first PDU Set sent by the source access network device to the terminal device is less than or equal to the number of redundant data packets corresponding to the first PDU Set.

[0363] In an embodiment of the present application, the transceiver module 910 is further configured to receive the lost data packets in the data packets that have been transmitted and completed in the first PDU Set from the source access network device.

[0364] In an embodiment of the present application, the transceiver module 910 is further configured to receive first indication information from the source access network device, where the first indication information is used to indicate that at least one first data packet being transmitted from the source access network device to the terminal device in the first PDU Set experiences packet loss.

[0365] In an embodiment of the present application, the transceiver module 910 is further configured to receive at least one first data packet from the source access network device.

[0366] Among them, all relevant contents of each step involved in the above method embodiment can be cited in the function description of the corresponding functional module, and will not be elaborated here. Optionally, the communication device may further include a storage module 930, and the storage module 930 may be used to store instructions and / or data, and the processing module 920 may read the instructions and / or data in the storage module 930.

[0367] In an embodiment of the present application, the first communication node is presented in the form of dividing each functional module in an integrated manner. Here, the "module" may refer to a specific ASIC, circuit, a processor and a memory that execute one or more software or firmware programs, an integrated logic circuit, and / or other devices that can provide the above functions. In a simple embodiment, those skilled in the art can think that the communication device can adopt Figure 6 the form of the communication device 600 shown.

[0368] For example, Figure 6 the processor 601 in the communication device 600 shown can call the computer-executable instructions stored in the memory 603, so that the communication device 600 executes the sensing method in the above method embodiment.

[0369] Specifically, Figure 9 the functions / implementation processes of the transceiver module 910 and the processing module 920 in can be implemented by Figure 6 the processor 601 in the communication device 600 shown calling the computer-executable instructions stored in the memory 603. Or, Figure 9 the function / implementation process of the processing module 920 in can be implemented by Figure 6 the processor 601 in the communication device 600 shown calling the computer-executable instructions stored in the memory 603, Figure 9 the function / implementation process of the transceiver module 910 in can be implemented by Figure 6 the communication interface 604 in the communication device 600 shown.

[0370] It should be understood that one or more of the above modules or units can be implemented by software, hardware, or a combination of both. When any of the above modules or units is implemented by software, the software exists in the form of computer program instructions and is stored in the memory. The processor can be used to execute the program instructions and implement the above method flow. The processor can be built into a SoC (system on a chip) or an ASIC, or it can be an independent semiconductor chip. In addition to the core for the processor to execute software instructions for arithmetic or processing, it may further include necessary hardware accelerators, such as a field programmable gate array (FPGA), a PLD (programmable logic device), or a logic circuit for implementing dedicated logical operations.

[0371] When the above modules or units are implemented in hardware, the hardware can be any one or any combination of a CPU, a microprocessor, a digital signal processing (DSP) chip, a microcontroller unit (MCU), an artificial intelligence processor, an ASIC, an SoC, an FPGA, a PLD, a dedicated digital circuit, a hardware accelerator, or a non-integrated discrete device, which can run the necessary software or execute the above method flow without relying on software.

[0372] Optionally, an embodiment of the present application further provides a communication device (for example, the communication device can be a chip or a chip system), which includes a processor for implementing the method in any of the above method embodiments. In a possible design, the communication device further includes a memory. The memory is used to store necessary program instructions and data, and the processor can call the program code stored in the memory to instruct the communication device to execute the method in any of the above method embodiments. Of course, the memory may not be in the communication device. When the communication device is a chip system, it can be composed of chips or can include chips and other discrete devices, and the embodiments of the present application do not make specific limitations on this.

[0373] Optionally, an embodiment of the present application further provides a computer-readable storage medium, in which computer programs or instructions are stored. When they run on a communication device, the communication device can execute the method described in any of the above method embodiments or any of its implementation manners.

[0374] Optionally, an embodiment of the present application further provides a communication system, which includes the communication device described in the above method embodiment.

[0375] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented using a software program, it can be implemented in whole or in part 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 processes or functions according to the embodiments of the present application are generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. The computer instructions can be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions can be transmitted from a website, a computer, a server, or a data center to another website, computer, server, or data center in a wired manner (such as coaxial cable, optical fiber, digital subscriber line (DSL)) or a wireless manner (such as infrared, wireless, microwave, etc.). The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device such as a server or a data center that contains one or more media integrated therein. The available medium can be a magnetic medium (such as a floppy disk, a hard disk, a magnetic tape), an optical medium (such as a DVD), or a semiconductor medium (such as a solid state disk (SSD)), etc.

[0376] Although the present application has been described in conjunction with various embodiments, however, in the process of implementing the claimed present application, those skilled in the art can understand and implement other variations of the disclosed embodiments by viewing the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other components or steps, and "a" or "one" does not exclude a plurality. A single processor or other unit can implement several functions recited in the claims. Certain measures are recited in mutually different dependent claims, but this does not mean that these measures cannot be combined to produce good results.

[0377] Although the present application has been described in conjunction with specific features and their embodiments, it is obvious that various modifications and combinations can be made without departing from the scope of the present application. Accordingly, the present specification and the drawings are merely exemplary descriptions of the present application defined by the appended claims, and are considered to have covered any and all modifications, variations, combinations, or equivalents within the scope of the present application. Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalent technologies, the present application is also intended to include these changes and modifications.

Claims

1. A communication method, characterized in that, it includes: The access network device receives first indication information from the session management function network element, and the first indication information is used to instruct the access network device to add first information to a first protocol data unit set (PDU Set); The access network device receives one or more data packets of the first PDU Set from the user plane function network element; The access network device sends one or more data packets of the first PDU Set to the first terminal device, wherein at least one of the one or more data packets of the first PDU Set sent to the first terminal device carries the first information, and the first information is used for the first terminal device to process the data packets of the first PDU Set according to the first information when sending the first PDU Set to the second terminal device.

2. The method according to claim 1, characterized in that, the method further includes: the access network device determines the first information according to the transmission status of the data packets of the first PDU Set sent to the first terminal device.

3. The method according to claim 1, characterized in that, the first information includes at least one of the following: the sequence number information of the first PDU Set, the sequence number information of each data packet in the first PDU Set, or the indication information of the last data packet in the first PDU Set; wherein, when the first information is used for the first terminal device to process the data packets of the first PDU Set when sending the first PDU Set to the second terminal device, it includes: at least one of the sequence number information of the first PDU Set, the sequence number information of each data packet in the first PDU Set, or the indication information of the last data packet in the first PDU Set is used for the first terminal device to determine that one or more data packets received from the access network device belong to the first PDU Set.

4. The method according to any one of claims 1 to 3, characterized in that, the first information includes a first time delay, and the first time delay is the transmission time delay budget of the first PDU Set from the first terminal device to the second terminal device.

5. The method according to claim 4, characterized in that, the first time delay is determined according to the time when the access network device sends the first data packet of the first PDU Set to the first terminal device and the packet scheduling delay budget (PSDB) of the first PDU Set, and the PSDB of the first PDU Set is used to represent the transmission time delay budget of the first PDU Set.

6. The method according to any one of claims 1 to 5, characterized in that, the method further includes: The access network device sends second indication information to the first terminal device, and the second indication information is used to indicate that packet loss occurs during the process of the access network device sending the data packets of the first PDU Set to the first terminal device.

7. A communication method, characterized in that, Including: A first terminal device receives one or more data packets from an access network device, the one or more data packets belonging to a first protocol data unit set (PDU Set), and at least one of the one or more data packets carries first information; The first terminal device processes the data packets of the first PDU Set according to the first information.

8. The method according to claim 7, wherein, The first information is determined by the access network device according to the transmission status of the data packets of the first PDU Set sent to the first terminal device.

9. The method according to claim 7, wherein, The first information includes at least one of the following: sequence number information of the first PDU Set, sequence number information of each data packet in the first PDU Set, or indication information of the last data packet in the first PDU Set; The first terminal device processes the data packets of the first PDU Set according to the first information, including: The first terminal device determines that one or more data packets received from the access network device belong to the first PDU Set according to at least one of the sequence number information of the first PDU Set, the sequence number information of each data packet in the first PDU Set, or the indication information of the last data packet in the first PDU Set.

10. The method according to any one of claims 7 to 9, wherein, The first information includes a first time delay, and the first time delay is the transmission time delay budget of the first PDU Set from the first terminal device to the second terminal device; The first terminal device processes the data packets of the first PDU Set according to the first information, including: When one or more data packets received by the first terminal device from the access network device satisfy the first time delay, the first terminal device sends the data packets of the first PDU Set to the second terminal device.

11. The method according to claim 10, wherein, The first time delay is determined according to the time when the access network device sends the first data packet of the first PDU Set to the first terminal device and the packet scheduling delay budget (PSDB) of the first PDU Set, and the PSDB of the first PDU Set is used to represent the transmission time delay budget of the first PDU Set.

12. The method according to any one of claims 7 to 11, wherein, The method further includes: The first terminal device receives second indication information from the access network device, and the second indication information is used to indicate that packet loss occurs during the process of the access network device sending the data packets of the first PDU Set to the first terminal device; The first terminal device determines not to send the data packets of the first PDU Set to the second terminal device according to the second indication information.

13. The method according to claim 12, wherein, The first terminal device determines not to send the data packets of the first PDU Set to the second terminal device according to the second indication information, including: The first terminal device determines the currently accumulated first packet loss count according to the quantity of the received second indication information, where the first packet loss count includes the number of packets lost during the process of the access network device sending the data packets of the first PDU Set to the first terminal device, and / or the number of packets lost during the process of the first terminal device sending the data packets of the first PDU Set to the second terminal device; When the first packet loss count is greater than a first threshold, the first terminal device determines not to send the data packets of the first PDU Set to the second terminal device.

14. A communication device, characterized in that, it includes: a transceiver module, configured to receive first indication information from a session management function network element, where the first indication information is used to instruct the access network device to add first information to a first protocol data unit set (PDU Set); the transceiver module is further configured to receive one or more data packets of the first PDU Set from a user plane function network element; the transceiver module is further configured to send one or more data packets of the first PDU Set to the first terminal device, where at least one of the one or more data packets of the first PDU Set sent to the first terminal device carries the first information, and the first information is used for the first terminal device to process the data packets of the first PDU Set according to the first information when sending the first PDU Set to a second terminal device.

15. The device according to claim 14, characterized in that, the communication device further includes a processing module, configured to determine the first information according to the transmission status of the data packets of the first PDU Set sent to the first terminal device.

16. The device according to claim 14, characterized in that, the first information includes at least one of the following: the sequence number information of the first PDU Set, the sequence number information of each data packet in the first PDU Set, or the indication information of the last data packet in the first PDU Set; where the first information is used for the first terminal device to process the data packets of the first PDU Set according to the first information when sending the first PDU Set to a second terminal device, including: at least one of the sequence number information of the first PDU Set, the sequence number information of each data packet in the first PDU Set, or the indication information of the last data packet in the first PDU Set is used for the first terminal device to determine that one or more data packets received from the access network device belong to the first PDU set.

17. The device according to any one of claims 14 to 16, characterized in that, The first information includes a first time delay, which is the transmission time delay budget of the first PDU Set from the first terminal device to the second terminal device.

18. The apparatus according to claim 17, wherein, the first time delay is determined according to the time when the access network device sends the first data packet of the first PDU Set to the first terminal device and the PSDB of the first PDU Set, and the PSDB of the first PDU Set is used to represent the transmission time delay budget of the first PDU Set.

19. The apparatus according to any one of claims 14 to 18, wherein, the method transceiver module is further configured to: send second indication information to the first terminal device, where the second indication information is used to indicate that packet loss occurs during the process of the access network device sending the data packets of the first PDU Set to the first terminal device.

20. A communication apparatus, wherein, comprises: a transceiver module, configured to receive one or more data packets from an access network device, the one or more data packets belong to a first protocol data unit set (PDU Set), and at least one of the one or more data packets carries first information; a processing module, configured to process the data packets of the first PDU Set according to the first information.

21. The apparatus according to claim 20, wherein, the first information is determined by the access network device according to the transmission status of the data packets of the first PDU Set sent to the first terminal device.

22. The apparatus according to claim 20, wherein, the first information includes at least one of the following: sequence number information of the first PDU Set, sequence number information of each data packet in the first PDU Set, or indication information of the last data packet in the first PDU Set; The processing module is configured to process the data packets of the first PDU Set according to the first information, including: the processing module is configured to determine that one or more data packets received from the access network device belong to the first PDU Set according to at least one of the sequence number information of the first PDU Set, the sequence number information of each data packet in the first PDU Set, or the indication information of the last data packet in the first PDU Set.

23. The apparatus according to any one of claims 20 to 22, wherein, the first information includes a first time delay, which is the transmission time delay budget of the first PDU Set from the first terminal device to the second terminal device; The processing module is configured to process the data packets of the first PDU Set according to the first information, including: when the processing module determines that one or more data packets received from the access network device meet the first time delay, the transceiver module sends the data packets of the first PDU Set to the second terminal device.

24. The apparatus according to claim 23, wherein, The first time delay is determined according to the time when the access network device sends the first data packet of the first PDU Set to the first terminal device and the packet delay budget (PSDB) of the first PDU Set, and the PSDB of the first PDU Set is used to represent the transmission delay budget of the first PDU Set.

25. The apparatus according to any one of claims 20 to 24, wherein, the transceiver module is further configured to receive second indication information from the access network device, and the second indication information is used to indicate that packet loss occurs during the process of the access network device sending the data packets of the first PDU Set to the first terminal device; the processing module is further configured to determine not to send the data packets of the first PDU Set to the second terminal device according to the second indication information.

26. The apparatus according to claim 25, wherein, the processing module is further configured to determine not to send the data packets of the first PDU Set to the second terminal device according to the second indication information, including: the processing module is further configured to determine the current cumulative number of first packet losses according to the number of the received second indication information, and the first packet loss number includes the number of packet losses that occur during the process of the access network device sending the data packets of the first PDU Set to the first terminal device, and / or the number of packet losses that occur during the process of the first terminal device sending the data packets of the first PDU Set to the second terminal device; when the number of the first packet losses is greater than a first threshold, the processing module determines not to send the data packets of the first PDU Set to the second terminal device.

27. A communication apparatus, wherein, the communication apparatus includes a module for executing the method according to any one of claims 1 to 6, or includes a module for executing the method according to any one of claims 7 to 13.

28. A communication apparatus, wherein, the communication apparatus includes a processor; the processor is configured to execute the method according to any one of claims 1 to 6, or cause the communication apparatus to execute the method according to any one of claims 7 to 13.

29. A computer-readable storage medium, wherein, the computer-readable storage medium includes instructions, and when the instructions are run, the method according to any one of claims 1 to 6 is implemented, or the method according to any one of claims 7 to 13 is implemented.

30. A computer program product, wherein, the computer program product includes instructions, and when the instructions are run, the method according to any one of claims 1 to 6 is implemented, or the method according to any one of claims 7 to 13 is implemented.

31. A communication system, wherein, the communication system includes the communication apparatus according to any one of claims 14 to 19 and the communication apparatus according to any one of claims 20 to 26.

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