Communication method and communication apparatus

Abstract

Provided in the embodiments of the present application are a communication method and a communication apparatus, which enable the transmission of a first PDU set in a cascading scenario to be implemented. The method comprises: an access network device receiving first instruction information from a session management function network element, wherein the first instruction information is configured to instruct the access network device to add first information to a first protocol data unit set (PDU set); the access network device receiving one or more data packets of the first PDU set from a user plane function network element; and the access network device sending the one or more data packets of the first PDU set to a first terminal device, wherein at least one data packet among 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 by the first terminal device to process the data packets of the first PDU set on the basis of the first information when sending the first PDU set to a second terminal device.

Description

Communication method and communication device

[0001] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office on December 11, 2023, with application number 202311703401.9 and application name “Communication Method and Communication Device”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of communications, and more specifically, to a communication method and a communication device. Background Art

[0003] Currently, for real-time media services, such as the emerging virtual reality (VR) / artificial reality (AR) / mixed reality (MR) and cloud gaming services, end-to-end latency has extremely stringent requirements, and the corresponding data processing granularity of upper-layer media services during encoding and transmission is no longer based on the granularity of data packets. For example, when encoding at the media layer, it is often processed at granularity such as media frames or fragments, that is, media frames, fragments, etc. can be encoded independently; at the same time, the receiving side will also perform decoding and display processing at the corresponding granularity such as media frames or fragments. Basic data units such as media frames or fragments often contain multiple data packets. The standard calls the basic data unit of the above media service layer a protocol data unit set (PDU Set). PDU Set is the basic data unit that can be independently processed by the upper service layer.

[0004] However, current technical solutions do not consider scenarios where multiple nodes collaborate to implement PDU Set processing. For example, in a cascade scenario, where a first terminal device is connected to a second terminal device, there is currently no solution for joint processing of PDU Sets in such a cascaded scenario. Summary of the Invention

[0005] The embodiments of the present application provide a communication method and a communication device, which can realize the transmission of the first PDU Set in a cascade scenario or a switching scenario.

[0006] To achieve the above objectives, this application adopts the following technical solutions:

[0007] In a first aspect, a communication method is provided, which can be executed by an access network device, or by a component of the access network device, such as a processor, chip, or chip system of the access network device, or by a logic module or software that can implement all or part of the functions of the access network device. Taking the method as an example that can be executed by the access network device, the method includes: the access network device receives first indication information from a session management function network element, 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, 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.

[0008] The communication method provided by the embodiment of the present application is that the access network device adds the first information in 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 that instructs the access network device to add the first information in 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 scheme enables the intermediate transmission node in the cascade 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 cascade 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 terminal device of the first PDU Set based on the first information; or for example, the first terminal device determines whether to send the data packet of the first PDU Set to the second terminal device based on the first information.

[0009] In combination with the first aspect described above, the communication method provided in an embodiment of the present application further includes: the access network device determining first information based on 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 used by the first terminal device to send the first PDU Set to the second terminal device based on the transmission status of the data packets of the first PDU Set sent to the first terminal device, thereby 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 to be carried in the data packet of the first PDU Set subsequently sent by the access network device to the first terminal device based on the delay of the data packet of the first PDU Set that has been sent to the first terminal device, so that the updated first delay is more accurate, thereby avoiding the waste of transmission resources caused by sending the data packet of the first PDU Set to the second terminal device according to the unupdated first delay, which causes the second terminal device to not have time to decode the first PDU Set; for another example, the access network device determines whether to carry a packet loss indication in the data packet of the first PDU Set subsequently sent to the first terminal device based on the packet loss situation of the data packet of the first PDU Set that has been sent to the first terminal device, so as to avoid the waste of transmission resources caused by still sending the data packet of the first PDU Set to the second terminal device when packet loss occurs and the first PDU Set cannot be correctly decoded.

[0010] In combination with the above-mentioned first aspect, in a possible implementation manner, 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.

[0011] Among them, the first information is used when the first terminal device sends the first PDU Set to the second terminal device, and the data packets of the first PDU Set are processed according to the first information, including: the sequence number information of the first PDU Set, the sequence number information of each data packet in the first PDU Set, or at least one of 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 received data packets belonging to the first PDU Set to the second terminal device, thereby preparing for the execution of PDU Set granularity transmission. Among them, the data packets are transmitted in the form of PDU Set, which can ensure that they can be encoded and processed at the granularity of PDU Set at the sending end, and can be decoded and displayed at the granularity of PDU Set at the receiving end, thereby achieving end-to-end PDU Set granularity service experience guarantee.

[0012] In conjunction with the first aspect described above, in one possible implementation, the first information includes a first delay, which is used to indicate the transmission delay budget for the first PDU Set from the first terminal device to the second terminal device, that is, the maximum transmission delay of the first PDU Set from the first terminal device to the second terminal device. Specifically, the first delay can be the upper limit of the transmission delay from the time the first PDU Set arrives at the first terminal device to the time the last packet of the first PDU Set is sent to the second terminal device, or the upper limit of the transmission delay for all packets of the first PDU Set to be sent to the second terminal device. This solution ensures that the transmission delay threshold of the first PDU Set is met when the first PDU Set is sent from the access network device to the second terminal device via the first terminal device. Furthermore, the first terminal device sends packets of the first PDU Set to the second terminal device if one or more packets of the first PDU Set received from the access network device meet the first delay. If packets of the first PDU Set are still sent to the second terminal device even if the first delay is not met, the second terminal device will not have time to decode and display the first PDU Set, resulting in a waste of transmission resources.

[0013] In combination with the above-mentioned first aspect, in a possible implementation method, in an embodiment of the present application, the first delay is determined based on the time when the access network device sends the first data packet of the first PDU Set to the first terminal device and the delay budget PSDB of the first PDU Set, or the first delay is determined based on the time when the access network device receives the first PDU Set, the time when the first data packet of the first PDU Set is sent to the first terminal device, and the delay budget PSDB of the first PDU Set, wherein the PSDB of the first PDU Set is used to characterize the transmission delay budget of the first PDU Set.

[0014] In combination with the first aspect above, in one possible implementation, the communication method provided in an embodiment of the present application further includes: the access network device sends second indication information to the first terminal device, where the second indication information is used to indicate that packet loss occurred 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 can enable the first terminal device to determine not to send the data packets in the first PDU Set that have not yet been sent to the second terminal device based on the second indication information, thereby avoiding the waste of transmission resources caused by still sending the data packets of the first PDU Set to the second terminal device when packet loss occurs and the first PDU Set cannot be correctly decoded.

[0015] In a second aspect, a communication method is provided. The method can be executed by a first terminal device, or by a component of the first terminal device, such as a processor, chip, or chip system of the first terminal device, or can be implemented by a logic module or software that can implement all or part of the functions of the first terminal device. Taking the method that 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 belonging to a first protocol data unit set (PDU Set), and at least one of the one or more data packets carries first information; and the first terminal device processes the data packets of the first PDU Set based on the first information.

[0016] In the communication method provided by an embodiment of the present application, a first terminal device receives a first PDU Set from an access network device, and processes the data packets of the first PDU Set according to the first information added in 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 cascade 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 cascade 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 first terminal device based on the first information; or for example, the first terminal device determines whether to send the data packet of the first PDU Set to the second terminal device based on the first information.

[0017] In conjunction with the above-mentioned second aspect, in one possible implementation, in an embodiment of the present application, the first information is determined by the access network device based on the transmission status of the data packet of the first PDU Set sent to the first terminal device. This solution enables the access network device to determine the first information used by the first terminal device to send the first PDU Set to the second terminal device based on the transmission status of the data packet 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 based on the first information, so that the subsequent transmission of the data packet of the first PDU Set is more accurate. For example, the access network device determines the updated first delay to be carried in the data packet of the first PDU Set subsequently sent by the access network device to the first terminal device based on the delay of the data packet of the first PDU Set that has been sent to the first terminal device, so that the updated first delay is more accurate, thereby avoiding the waste of transmission resources caused by sending the data packet of the first PDU Set to the second terminal device according to the unupdated first delay, which causes the second terminal device to not have time to decode the first PDU Set; for another example, the access network device determines whether to carry a packet loss indication in the data packet of the first PDU Set subsequently sent to the first terminal device based on the packet loss situation of the data packet of the first PDU Set that has been sent to the first terminal device, so as to avoid the waste of transmission resources caused by still sending the data packet of the first PDU Set to the second terminal device when packet loss occurs and the first PDU Set cannot be correctly decoded.

[0018] In combination with the above-mentioned second aspect, 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 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 the one or more received data packets belonging to the first PDU Set to the second terminal device, thereby preparing for the execution of PDU Set granularity transmission. Among them, the data packets are transmitted in the form of PDU Set, which can ensure that they can be encoded and processed at the granularity of PDU Set at the sending end and can be decoded and displayed at the granularity of PDU Set at the receiving end, thereby achieving end-to-end PDU Set granularity service experience guarantee.

[0019] In combination with the second aspect above, in one possible implementation, the first information includes a first delay, and 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; the first terminal device processes the data packet 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 delay, the first terminal device sends the data packet of the first PDU Set to the second terminal device. This solution enables the first terminal device to send the data packet of the first PDU Set to the second terminal device when one or more data packets of the first PDU Set received from the access network device meet the first delay, ensuring that the transmission of the first PDU Set can meet the transmission delay budget; if the data packet of the first PDU Set is still sent to the second terminal device when the first delay is not met, the second terminal device cannot receive the first PDU Set within the transmission delay budget, resulting in the transmission of the first PDU Set failing to meet the transmission delay budget requirement, causing the second terminal device to be unable to decode and display the first PDU Set in a timely manner.

[0020] In combination with the above-mentioned second aspect, in a possible implementation method, in an embodiment of the present application, the first delay is determined based on the time when the access network device sends the first data packet of the first PDU Set to the first terminal device and the delay budget PSDB of the first PDU Set. The PSDB of the first PDU Set is used to characterize the transmission delay budget of the first PDU Set, that is, the transmission delay upper limit used by the first PDU Set when it is received from the access network device and sent to the second terminal device, or the transmission delay upper limit used by the first PDU Set when it is received from the core network and sent to the second terminal device.

[0021] In combination with the above-mentioned second aspect, in a possible implementation, the communication method provided by the embodiment of the present application further includes: the first terminal device receives second indication information from the access network device, the second indication information is used to indicate that packet loss occurs in the process of the access network device sending the first PDU Set data packet to the first terminal device, or the number of packet losses that occur; the first terminal device determines not to send the first PDU Set data packet to the second terminal device based on the second indication information. This solution can enable the first terminal device to determine not to send the data packet in the first PDU Set that has not been sent to the second terminal device based on the second indication information, thereby avoiding the waste of transmission resources caused by still sending the first PDU Set data packet to the second terminal device when the number of packet losses that occur causes the first PDU Set to be unable to be decoded and displayed on the second terminal device side.

[0022] In combination with the above-mentioned second aspect, in a possible implementation, in an embodiment of the present application, the first terminal device determines not to send data packets of the first PDU Set to the second terminal device based on the second indication information, including: the first terminal device determines the currently accumulated first packet loss number based on one or more received second indication information, the first packet loss number including the number of packet losses that occur in the process of the access network device sending data packets of the first PDU Set to the first terminal device, and / or the number of packet losses that occur in the process of the first terminal device sending data packets of the first PDU Set to the second terminal device; when the first packet loss number is greater than the first threshold, the first terminal device determines not to send 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 data packets in the first PDU Set that have not yet been sent to the second terminal device based on the first packet loss number, thereby avoiding the waste of transmission resources caused by still sending 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 on the second terminal device side.

[0023] On the third aspect, a communication method is provided, which can be executed by a source access network device, or by a component of the source access network device, such as a processor, chip, or chip system of the source access network device, or by a logic module or software that can implement all or part of the functions of the source access network device. Taking the method that can be executed by the source access network device as an example, the method includes: the source access network device receives a first protocol data unit set PDU Set; the source access network device 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 in the first PDU Set that have not yet been transmitted to the target access network device, wherein at least one of the data packets in the first PDU Set that have not yet been transmitted carries first information, and the first information is used for the target access network device to process the one or more data packets from the source access network device according to the first information when the target access network device sends one or more data packets from the source access network device to the terminal device.

[0024] In the communication method provided by an embodiment of the present application, a source access network device receives a first PDU Set from a user plane functional network element and sends part of the data packets of the first PDU Set to a terminal device. In the case where the terminal device switches to a target access network device, the source access network device sends the data packets in the first PDU Set that have not yet been transmitted to the target access network device, wherein at least one of the data packets in the first PDU Set that have not yet been transmitted 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 by the source access network device and the target access network device in a switching scenario, such as 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.

[0025] In combination with the third aspect above, the communication method provided in the embodiment of the present application also includes that the source access network device determines the first information based on the transmission status of the data packet 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 redundant packet ratio or packet loss indication carried in one or more data packets sent to the target access network device based on 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, thereby 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.

[0026] In combination with the above-mentioned third aspect, in a possible implementation manner, 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.

[0027] Among them, the first information is used when the target access network device sends one or more data packets from the source access network device to the terminal device, and the one or more data packets from the source access network device are processed according to the first information, including: the sequence number information of the first PDU Set, the sequence number information of each data packet in the first PDU Set, or at least one of 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 scheme can enable the target access network device to send the one or more data packets received belonging to the first PDU Set to the terminal device, thereby preparing for the execution of PDU Set granularity transmission. Among them, the data packets are transmitted in the form of PDU Set, which can ensure that they can be encoded and processed at the granularity of PDU Set at the sending end, and can be decoded and displayed at the granularity of PDU Set at the receiving end, thereby achieving end-to-end PDU Set granularity service experience guarantee.

[0028] In conjunction with the third aspect above, in one possible implementation, the first information includes a first delay, which is used to indicate the transmission delay budget for the data packets in the first PDU Set that have not yet been transmitted, or the first delay is used to indicate the transmission delay budget for the data packets in the first PDU Set that the source access network device sends to the target access network device. Specifically, the first delay can be the upper limit of the transmission delay for the data packets in the first PDU Set that have not yet been transmitted, from the time the target access network device receives the data packets that have not yet been transmitted to the time they are sent 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 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 delay range, ensuring that the transmission of the first PDU Set can meet the transmission delay budget requirement. If the untransmitted data packets 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 delay is not met, the terminal device will not have time to decode and display the first PDU Set, which will result in a waste of transmission resources.

[0029] In conjunction with the third aspect described above, in one possible implementation, in an embodiment of the present application, the first delay is determined based on the delay budget PSDB of the first PDU Set. The PSDB of the first PDU Set is used to represent the transmission delay budget of the first PDU Set. (Ignoring handover of the terminal device, the PSDB of the first PDU Set is the upper limit requirement for the transmission delay from the time the access network device receives the first PDU Set to the time the first PDU Set is sent to the terminal device, or the upper limit requirement for the transmission delay from the time the user plane function network element receives the first PDU Set to the time the first PDU Set is sent to the terminal device. Exemplarily, receiving the first PDU Set by the access network device or the user plane function network element means receiving the first data packet of the first PDU Set.)

[0030] In combination with the above-mentioned third aspect, in a possible implementation method, 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 packet that has not yet been transmitted 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.

[0031] In conjunction with the third aspect above, in one 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 that have not yet been transmitted in the first PDU Set to the number of redundant packets corresponding to the data packets that have not yet been transmitted in the first PDU Set, or the first redundant packet ratio is the upper limit of tolerable packet loss among the data packets that have not yet been transmitted in the first PDU Set. This solution can avoid the waste of transmission resources caused by still sending data packets of the first PDU Set to the terminal device when the number of data packets lost 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.

[0032] In combination with the third aspect above, in a possible implementation, in an embodiment of the present application, the source access network device sends the data packets in the first PDU Set that have not yet been transmitted 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 meets the first condition, the source access network device sends the data packets in the first PDU Set that have not yet been transmitted to the target access network device. In this scheme, the source access network device sends the data packets in the first PDU Set that have not yet been transmitted to the target access network device when it determines that the data packets in the partial data packets of the first PDU Set currently sent to the terminal device can ensure the correct decoding of the first PDU Set, thereby avoiding the waste of transmission resources caused by sending the data packets in the first PDU Set that have not yet been transmitted to the target access network device when the first PDU Set cannot be correctly decoded.

[0033] In combination with the third aspect above, in a possible implementation, the first condition is that no packet loss occurs.

[0034] In combination with the third aspect above, in a possible implementation, the first condition is that the number of packet losses is less than or equal to the number of redundant data packets corresponding to the first PDU Set.

[0035] In combination with the third aspect above, in a possible implementation, the communication method provided in the embodiment of the present application further includes: the source access network device sends a first indication message to the target access network device, and the first indication message is used to indicate that at least one first data packet in the first PDU Set being transmitted to the terminal device through the source access network device has been lost. This solution enables the source access network device to promptly 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 has been lost, thereby avoiding the waste of transmission resources caused by the target access network device still sending the data packet 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.

[0036] In conjunction with the third aspect above, in a possible implementation, the first indication information is further used to indicate the number of at least one first data packet that has been lost. This solution allows the target access network device to determine the number of at least one first data packet that has been lost.

[0037] In combination with the third aspect above, in one possible implementation, the communication method provided in the embodiment 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 the target access network device not sending 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 in the first PDU Set being transmitted to the terminal device via the source access network device, thereby increasing the transmission success rate of data packets in the first PDU Set that have not been transmitted or have failed to be transmitted from the target access network device to the terminal device.

[0038] In a fourth aspect, a communication method is provided, which can be executed by a target access network device, or by a component of the target access network device, such as a processor, chip, or chip system of the target access network device, or can be implemented by a logic module or software that can realize all or part of the functions of the target access network device. Taking the method that can be executed by the target access network device as an example, the 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, the one or more data packets are data packets that have not yet been transmitted in the first protocol data unit set PDU Set, wherein at least one of the one or more data packets carries first information; the data packets that have not yet 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.

[0039] In the communication method provided by an embodiment of the present application, a source access network device receives a first PDU Set from a user plane functional network element and sends part of the data packets of the first PDU Set to a terminal device. In the case where the terminal device switches to a target access network device, the source access network device sends the data packets in the first PDU Set that have not yet been transmitted to the target access network device, wherein at least one of the data packets in the first PDU Set that have not yet been transmitted 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 scheme ensures the joint transmission of the first PDU Set by the source access network device and the target access network device in the switching scenario, such as 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.

[0040] In combination with the fourth aspect above, in a possible implementation, in an embodiment of the present application, the first information is determined by the source access network device based on the transmission status of the data packet 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 proportion of first redundant packets or packet loss indications carried in one or more data packets sent to the target access network device based on the packet loss status of the data packets that have been transmitted in the data packets of the first PDU Set sent to the terminal device, thereby 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.

[0041] In conjunction with the fourth aspect above, in one 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 target access network device processes one or more data packets from the source access network device based on the first information, including: the target access network device determines that the one or more data packets received from the source access network device belong to the first PDU Set based on 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 enables the target access network device to send the one or more received data packets belonging to the first PDU Set to the terminal device, thereby realizing transmission processing at the PDU Set granularity. The data packets are transmitted in the form of a PDU Set, which can ensure that they can be encoded and processed at the granularity of the PDU Set at the sending end and can be decoded and displayed at the granularity of the PDU Set at the receiving end, thereby realizing end-to-end PDU Set granularity service experience guarantee.

[0042] In conjunction with the fourth aspect above, in one possible implementation, the first information includes a first delay, which is used to indicate the transmission delay budget of the data packets that have not yet been transmitted in the first PDU Set, or the transmission delay budget of the data packets that the source access network device sends to the target access network device in the first PDU Set. Specifically, the first delay can be the upper limit of the transmission delay of the data packets that have not yet been transmitted in the first PDU Set from the target access network device receiving the data packets that have not yet been transmitted 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 the one or more data packets received from the source access network device meet the first delay, the target access network device sends the 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 the one or more data packets of the first PDU Set received from the source access network device according to the received first delay, and ensure that the one or more data packets of the first PDU Set sent from the source access network device to the terminal device within the first delay range ensure that the transmission of the first PDU Set can meet the transmission delay budget requirement. If one or more data packets of the first PDU Set from the source access network device that have not yet been transmitted are still sent to the terminal device without meeting the first delay, the terminal device will not have time to decode and display the first PDU Set, which will result in a waste of transmission resources.

[0043] In combination with the above-mentioned fourth aspect, in a possible implementation method, in an embodiment of the present application, 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.

[0044] In combination with the above-mentioned fourth aspect, in a possible implementation method, 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 packet that has not yet been transmitted 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.

[0045] In conjunction with the fourth aspect above, in one 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 that have not yet been transmitted in the first PDU Set to the number of redundant packets corresponding to the data packets that have not yet 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 yet been transmitted in the first PDU Set. The target access network device processes one or more data packets from the source access network device based on the first information, including: the target access network device determines a first number of data packets that are lost in the process of sending one or more data packets from the source access network device to the terminal device; if the first number 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 that have not yet been transmitted in the one or more data packets from the source access network device. This solution can avoid the waste of transmission resources caused by still sending data packets of the first PDU Set to the terminal device when the number of data packets that are lost 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.

[0046] In combination with the fourth aspect above, in a possible implementation, the packet loss situation of some data packets of the first PDU Set sent by the source access network device to the terminal device is that no packet loss occurs.

[0047] In combination with the fourth aspect above, in a possible implementation, the packet loss situation of some data packets of 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.

[0048] In conjunction with the fourth aspect above, the communication method provided in an embodiment of the present application further includes: the target access network device receiving the lost data packets from the already transmitted data packets in the first PDU Set from the source access network device. This solution can improve the transmission success rate of the first PDU Set.

[0049] In combination with the fourth aspect above, in a possible implementation, the communication method provided in the embodiment 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 in the first PDU Set being transmitted to the terminal device through the source access network device has been lost. This solution enables the source access network device to promptly 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 has been lost, thereby avoiding the waste of transmission resources caused by the target access network device still sending the data packet of 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.

[0050] In conjunction with the fourth aspect, in a possible implementation, the first indication information is further used to indicate the number of at least one first data packet that has been lost. This solution allows the target access network device to determine the number of at least one first data packet that has been lost.

[0051] In conjunction with the fourth aspect above, in one possible implementation, the communication method provided in the embodiment 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 in the first PDU Set being transmitted to the terminal device via the source access network device, thereby increasing the transmission success rate of data packets in the first PDU Set that have not been transmitted or have failed to be transmitted from the target access network device to the terminal device.

[0052] In a fifth aspect, a communication device is provided for implementing the various methods described above. The communication device may be the access network device described 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 described 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 described 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 described in the fourth aspect, or a device included in the target access network device, such as a chip.

[0053] The communication device includes modules, units, or means corresponding to the above-mentioned method, which can be implemented by hardware, software, or hardware executing corresponding software implementation. The hardware or software includes one or more modules or units corresponding to the above-mentioned functions.

[0054] 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), respectively configured to implement the output (or sending) and input (or receiving) functions of any of the above aspects and any possible designs thereof. The processing module may be configured to implement the processing functions of any of the above aspects and any possible designs thereof.

[0055] Optionally, the communication device further includes a storage module for storing program instructions and data.

[0056] In a sixth aspect, a communication device is provided, comprising: at least one processor configured to execute a computer program or instruction, or to cause the communication device to execute the method described in any of the above aspects through a logic circuit. The communication device may be the access network device described 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 described 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 described 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 described in the fourth aspect, or a device included in the target access network device, such as a chip.

[0057] 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 is integrated with the processor, or the memory is independent of the processor.

[0058] In one possible design, the communication device further includes a communication interface for inputting and / or outputting signals.

[0059] 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 (computer execution instructions are stored in a memory, may be read directly from the memory, or may pass through other devices) and transmit them to the processor.

[0060] In some possible designs, the communication interface is used to communicate with modules outside the communication device.

[0061] 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.

[0062] In a seventh aspect, a communication device is provided, comprising: a logic circuit and an interface circuit; the interface circuit is configured to input and / or output information; and the logic circuit is configured to execute the method described in any of the above aspects, processing the input information and / or generating output information. The communication device may be the access network device described 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 described 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 described 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 described in the fourth aspect, or a device included in the target access network device, such as a chip.

[0063] 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 output information, and the above-mentioned receiving action / function can be understood as input information.

[0064] In an eighth aspect, a computer-readable storage medium is provided, in which a computer program or instruction is stored. When the computer program or instruction is executed by a processor, the method described in any one of the above aspects is executed.

[0065] In a ninth aspect, a computer program product is provided, which, when executed by a processor, enables the method described in any one of the above aspects to be executed.

[0066] In a tenth aspect, a communication device is provided, which includes a module / unit for executing the method described in the first aspect, or the second aspect, or the third aspect, or the fourth aspect.

[0067] In the eleventh aspect, a communication system is provided, which includes the access network device described in the first aspect and the first terminal device described in the second aspect; or, the communication system includes the source access network device described in the third aspect and the target access network device described in the fourth aspect.

[0068] Among them, the technical effects brought about by any design method in the fifth to eleventh aspects can be referred to the technical effects brought about by different design methods in the above-mentioned first aspect, or second aspect, or third aspect, or fourth aspect, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] Figure 1 is a schematic diagram of the 5G network architecture;

[0070] FIG2 is a schematic diagram of the architecture of a layer 3 relay architecture;

[0071] FIG3 is a schematic diagram of a communication system provided in an embodiment of the present application;

[0072] FIG4 is a schematic diagram of another communication system provided in an embodiment of the present application;

[0073] FIG5 is a schematic diagram of transmission of a first PDU Set in a handover scenario provided by an embodiment of the present application;

[0074] FIG6 is a schematic structural diagram of a communication device 600 provided in an embodiment of the present application;

[0075] FIG7 is a schematic diagram of an example of a communication method provided in an embodiment of the present application;

[0076] FIG8 is a schematic diagram of another example of a communication method provided in an embodiment of the present application;

[0077] FIG9 is a schematic diagram of a communication device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0078] The communication method provided in the embodiments of the present application can be applied to various communication systems, such as wireless fidelity (Wi-Fi) network systems, vehicle to everything (V2X) communication systems, device-to-device (D2D) communication systems, vehicle network communication systems, fourth-generation (4G) mobile communication systems, such as long-term evolution (LTE) communication systems, world-wide interoperability for microwave access (WiMAX) communication systems, fifth-generation (5G) mobile communication systems (such as new radio (NR) systems), or future communication systems, such as 5.5G, sixth-generation (6G) mobile communication systems, etc.

[0079] To facilitate understanding, the relevant technologies of the embodiments of the present application are first briefly introduced.

[0080] Related technologies 1. Fifth generation (5G) network architecture:

[0081] The 5G network architecture defined in the 3rd Generation Partnership Project (3GPP) standard is mainly divided into two parts: the access network (AN) and the core network. As shown in Figure 1, terminal devices access the core network through the access network.

[0082] As shown in Figure 1, the access network may include radio access network (RAN) equipment, which is used to implement 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 function (UDM) network element. In addition, it may also include authentication server function (AUSF) network element, network slice selection function (NSSF) network element, application function (AF) network element, etc. The following is a brief introduction to the relevant network elements shown in Figure 1.

[0083] DN stands for data network (DN), which is mainly used to provide data transmission services to users, such as Internet Protocol (IP) Multimedia Service (IMS).

[0084] RAN equipment includes but is not limited to evolved base stations (NodeB or eNB or e-NodeB, evolutionary Node B), wireless fidelity (WiFi) access points (AP), etc.

[0085] The AMF network element is mainly responsible for mobility management in the mobile network, such as user location update, user network registration, user switching, etc.

[0086] The SMF network element is responsible for session management in mobile networks, such as session establishment, modification, and release. Specific functions include allocating IP addresses to users and selecting the UPF that provides packet forwarding capabilities.

[0087] The PCF network element is mainly responsible for providing policies to AMF and SMF, such as quality of service (QoS) policy and slice selection policy.

[0088] The UDM network element is mainly responsible for storing user data, such as contract information and authentication / authorization information.

[0089] The AF network element is mainly responsible for providing service requirements to the 3GPP network, such as influencing service routing and interacting with the PCF network element for policy control.

[0090] The UPF network element is mainly responsible for processing user messages, such as forwarding and billing.

[0091] The terminal device accesses the DN by establishing a protocol data unit (PDU) session (PDU session) between the terminal to the RAN to the UPF to the DN.

[0092] The AUSF network element is mainly responsible for providing terminal device authentication services for the AMF network element.

[0093] The NSSF network element is mainly responsible for selecting the network slice that serves the terminal device.

[0094] In addition, referring to Figure 1, Nx represents the logical interface or service-oriented 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; and N13 is the interface between the AUSF network element and the UDM network element.

[0095] Related Technology 2: Proximity-based services (ProSe) communications:

[0096] ProSe communication, also known as short-range service communication, is a typical service scenario in D2D communication. ProSe communication can include direct communication of proximity services and communication from proximity service terminal devices to network relay. For proximity service terminal device to network relay communication (referred to as ProSe relay communication), when a terminal device (referred to as terminal device 1) is out of network coverage, or the communication signal between it and the RAN device is poor, or other terminal devices (referred to as terminal device 2) are required 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 referred to as 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 referred to as 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 may be used to provide ProSe functions that support remote terminal devices to connect to the network, so that the remote terminal devices can communicate with the DN through the ProSe functions provided by the relay terminal device, that is, ProSe relay communication.

[0097] To support ProSe functionality, 3GPP introduced a layer 3 relay architecture.

[0098] Figure 2 is a schematic diagram of the architecture of the layer 3 relay architecture. As shown in Figure 2, 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 to achieve 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 to achieve ProSe communication. Alternatively, the relay terminal device may also establish or modify a PDU session for the remote terminal device so that the remote terminal device can perform an internet key exchange (IKE) process with a non-3GPP interworking function (N3IWF) through the PDU session to establish an internet protocol security (IPsec) tunnel for signaling and perform a non-access stratum (NAS) registration process. In this way, the remote terminal device can establish a PDU session of the remote terminal device through the PDU session established by the relay terminal device and the N3IWF, and obtain services from the DN to realize 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 there is no specific limitation on this.

[0099] It should be noted that in the layer 3 relay architecture, the remote terminal device can be called a 5G ProSe layer 3 remote terminal device, a ProSe layer 3 remote terminal device, or a layer 3 remote terminal device.

[0100] Related Technology 3. Quality of Service (QoS) flow.

[0101] In the 5G system (5GS), when a terminal device needs to communicate with a service, it establishes a PDU session. Within this PDU session, the corresponding QoS flow carries the service flow. Specifically, the terminal device obtains the internet protocol (IP) address of the network through the PDU session establishment process, thereby interacting with external service servers and achieving service communication. Based on the service flow description information, the 5GS maps the corresponding service to different QoS flows and performs the corresponding QoS processing.

[0102] Related technology 4. QoS processing mechanism at PDU Set granularity.

[0103] 5GC identifies the relationship between different data packets and PDU Sets, and schedules, processes, and transmits all data packets in the PDU Set as a whole to ensure the user's service experience.

[0104] In order to determine which data packets in the QoS flow belong to the same PDU Set, after the downlink data packet arrives at the UPF network element, the UPF network element determines the PDU Set accordingly and adds the corresponding PDU Set information to the data packet of the downlink PDU Set. The PDU Set information includes PDU Set sequence number (PSSN), PDU Set size information, indication information of the last data packet in the PDU Set, PDU Set importance (PSI), etc. The PDU Set information is added to the user plane general packet radio service (GPRS) tunneling protocol (GTP-U) layer of the data packet in the PDU Set to assist the RAN equipment in performing PDU Set QoS processing.

[0105] Before this process, the RAN device will receive the PDU Set QoS parameters from the SMF network element. The PDU Set QoS parameters include the PDU Set transmission delay budget (PSDB), PDU Set error rate (PSER), PDU Set integrity processing information (for example, the data packets in the PDU Set need to be transmitted successfully and completely, and packet loss or damage cannot be tolerated), etc. Among them, 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, PSDB refers to the upper limit of the transmission delay required from the UPF network element to receive the first data packet of the PDU Set to the transmission to the terminal device. Alternatively, PSDB can also be the upper limit of the transmission time required for each PDU Set from the RAN device to the terminal device. In this case, the PSDB is also called the RAN device PSDB. In the embodiment of the present 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 from the RAN device to receive the first data packet of the PDU Set to transmit the PDU Set to the terminal device.

[0106] The RAN device performs PDU Set processing based on the PDU Set information and PDU Set QoS parameters in the downlink data packet.

[0107] Related technology 5. Data packet transmission failure (packet loss) scenario.

[0108] In one possible implementation, when a data packet is transmitted between a RAN device and a terminal device, if the delay required for the data packet transmission exceeds the data packet transmission delay budget, the data packet may be considered lost. Specifically, if the data packet transmission delay budget is exhausted but the radio link control (RLC) layer does not have time to send the data packet to the media access control (MAC) layer for transmission, and the data packet remains in the RLC buffer, the data packet is considered lost. The data packet transmission delay budget for transmission between the RAN device and the terminal device is the access network data packet transmission delay budget.

[0109] In another possible implementation, a feedback mechanism exists between the RAN device and the terminal device, that is, the RAN device determines whether the data packet is successfully transmitted based on the feedback from the terminal device. Specifically, when a data packet is sent to the MAC layer for transmission, the MAC layer will determine whether the data packet will eventually be sent successfully based on the feedback from 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 reassemble the upper-layer data packet to ensure that the data packet is suitable for channel transmission). Furthermore, the MAC layer provides feedback to the upper-layer RLC or packet data convergence protocol (PDCP). This implementation ensures that the RAN device can perceive the packet loss of each data packet when scheduling transmission. It should be noted that the specific implementation will ultimately depend on the implementation of the RAN device product.

[0110] Related technology 6. PDU Set processing scenarios.

[0111] Depending on the application layer implementation, the following scenarios exist for the processing of PDU Set:

[0112] Processing scenario 1:

[0113] If a data packet in a PDU Set is lost or damaged, the entire PDU Set will be difficult to decode and display correctly.

[0114] Processing scenario 2:

[0115] Some data packets in a PDU Set are lost or damaged. The receiving client can recover, decode, and display the data packets received before the first lost data packet in the PDU Set, but it is difficult to correctly decode and display the subsequent data packets.

[0116] Processing scenario three:

[0117] The transmitter of the service layer / application layer will perform forward error correction (FEC) on the current PDU Set before sending the PDU Set, that is, by adding additional redundant data packets to avoid damage to 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 data packets lost in the PDU Set exceeds the maximum number of redundant packets, it will make it difficult to correctly decode and display the entire PDU Set. For example, a PDU Set includes 30 data packets. After FEC, the PDU Set includes 40 data packets, including 10 redundant data packets. During the transmission of the PDU Set, the number of packet loss is 10 or less, which does not affect the correct decoding and display of the PDU Set. It should be noted that in the following embodiments, if the processing scenario three is involved, that is, the PDU Set undergoes FEC processing, it is considered that the PDU Set contains redundant data packets.

[0118] After at least one of the above three processing scenarios occurs, the RAN device usually does not send the remaining data packets in the PDU Set (data packets that have not yet been transmitted).

[0119] The communication method provided in the embodiments of the present application is introduced below.

[0120] In the description of this application, unless otherwise specified, " / " indicates that the objects associated before and after are in an "or" relationship, for example, A / B can represent A or B; "and / or" in this application is merely a description of the association relationship of associated objects, indicating that three relationships may exist, for example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone, where A and B can be singular or plural.

[0121] In the description of this application, unless otherwise specified, "plurality" means two or more than two. "At least one of the following items" or similar expressions refers to any combination of these items, including any combination of single items or plural items. For example, at least one of a, b and / or c can be represented by: a, b, c, ab, ac, bc, or abc, where a, b, c can be single or plural.

[0122] In addition, to facilitate the clear description of the technical solutions of the embodiments of the present application, in the embodiments of the present application, the words "first" and "second" are used to distinguish between identical or similar items with substantially the same functions and effects. Those skilled in the art will understand that the words "first" and "second" do not limit the quantity or execution order, and the words "first" and "second" do not necessarily mean different.

[0123] In the embodiments of this application, words such as "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of this application should not be construed as being preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner to facilitate understanding.

[0124] It will be understood that the “embodiment” mentioned throughout the specification means that the specific features, structures or characteristics related to the embodiment 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 will be understood that in the various embodiments of the present application, the size of the sequence number of each process does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiment of the present application.

[0125] It is understood that some optional features in the embodiments of the present application may, in certain scenarios, be implemented independently of other features, such as the solution on which they are currently based, to solve corresponding technical problems and achieve corresponding effects. They may also be combined with other features in certain scenarios as needed. Accordingly, the devices provided in the embodiments of the present application may also implement these features or functions accordingly, which will not be described in detail here.

[0126] In this application, unless otherwise specified, the same or similar parts between the various embodiments can refer to each other. In the various embodiments of this application, unless otherwise specified and there is no logical conflict, the terms and / or descriptions between different embodiments are consistent and can be referenced to each other, and the technical features in different embodiments can be combined to form new embodiments based on their inherent logical relationships. The following description of the embodiments of this application does not constitute a limitation on the scope of protection of this application.

[0127] To facilitate understanding of the embodiments of the present application, the communication system applicable to the embodiments of the present application is first described in detail using the communication system in the cascade scenario shown in Figure 3 and the communication system in the switching scenario shown in Figure 4 as examples.

[0128] For example, Figure 3 is a schematic diagram of a communication system provided in an embodiment of the present application. As shown in Figure 3, the communication system includes: an access network device and a first terminal device.

[0129] An access network device is used 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 PDU Set, where the first information is used by the first terminal device to send the first PDU Set to the second terminal device.

[0130] The access network device is also used to receive one or more data packets of the first PDU Set from the user plane functional network element, and send 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 by the access network device to the first terminal device carries the first information.

[0131] The first terminal device is used 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.

[0132] Optionally, as shown in FIG3 , the communication system includes a session management function network element and / or a user plane function network element.

[0133] The session management function network element is used to send first indication information to the access network device.

[0134] The user plane functional network element is configured to send one or more data packets of the first PDU Set to the access network device.

[0135] Optionally, as shown in FIG3 , the communication system further includes: a second terminal device, configured to receive a data packet of the first PDU Set from the first terminal device.

[0136] Optionally, in a cascade scenario, the first terminal device may be a relay terminal device in the layer 3 relay architecture as shown in FIG. 2 , and the second terminal device may be a remote terminal device in the layer 3 relay architecture as shown in FIG. 2 .

[0137] For example, Figure 4 is a schematic diagram of another communication system provided in an embodiment of the present application. As shown in Figure 4, the communication system includes: a source access network device, a target access network device, and a terminal device.

[0138] The source access network device is used to receive the first PDU Set from the user plane functional network element and send a partial data packet of the first PDU Set to the terminal device.

[0139] When the terminal device switches to the target access network device, the source access network device is further configured to send data packets in the first PDU Set that have not yet been transmitted to the target access network device. At least one of the data packets in the first PDU Set that have not yet been transmitted carries first information, and the first information is used to transmit the data packets in the first PDU Set that have not yet been transmitted.

[0140] 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.

[0141] Optionally, in an embodiment 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 part of the data packets of the first PDU Set from the source access network device.

[0142] Optionally, the terminal device is further used to receive one or more data packets from the target access network device.

[0143] Optionally, as shown in FIG4 , the communication system includes a user plane functional network element.

[0144] For example, Figure 5 shows a schematic diagram of the transmission of the first PDU Set in a handover scenario. As shown in Figure 5, before the terminal device switches to the target access network device, the source access network device sends some 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 yet been transmitted to the target access network device. Furthermore, the target access network device may send one or more data packets from the source access network device to the terminal device.

[0145] Optionally, the terminal device involved in the present application (for example, the first terminal device or the second terminal device in the communication system shown in FIG3 , or the terminal device in the communication system shown in FIG4 ) can be a user equipment (UE), an access terminal, a terminal unit, a user station, a terminal station, a mobile station, a mobile station, a remote station, a remote terminal, a user terminal terminal equipment, TE), a mobile device, a wireless communication device, a terminal agent, a tablet computer (pad), a handheld device with wireless communication function, a computing device or other processing device connected to a wireless modem, a vehicle-mounted device, a vehicle-mounted communication module, a wearable device, or a terminal device. The access terminal can be a cellular phone, a cordless phone, a session initiation protocol (SIP) phone, a wireless local loop (WLL) station, a personal digital assistant (PDA), a handheld device with wireless communication function, a computing device or other processing device connected to a wireless modem, a vehicle-mounted device, a drone, a robot, a smart point of sale (point of The invention relates to a wireless communication device for a point of sale (POS) machine, a customer-premises equipment (CPE) or a wearable device, a virtual reality (VR) terminal device, an augmented reality (AR) terminal device, a wireless terminal in industrial control, a wireless terminal in self-driving, a wireless terminal in remote medical, a wireless terminal in a smart grid, a wireless terminal in transportation safety, a wireless terminal in a smart city, a wireless terminal in a smart home, etc. Alternatively, the terminal may be a terminal with a communication function in the Internet of Things (IoT), such as a terminal in V2X (such as a vehicle networking device), a terminal in D2D communication, or a terminal in M2M communication. The terminal may be mobile or fixed. In addition, the embodiments of the present application do not limit the device form of the terminal. The device for realizing the function of the terminal device may be a terminal device; or it may be a device that can support the terminal device to realize the function, such as a chip system. The device may be installed in the terminal device or used in combination with the terminal device.In the embodiment of the present application, the chip system can be composed of chips, or can include chips and other discrete devices.

[0146] Optionally, the access network device involved in the present application (for example, the access network device in the communication system shown in Figure 3, or the source access network device and the target access network device in the communication system shown in Figure 4) can be an evolved base station (NodeB or eNB or e-NodeB, evolutionary Node B) in a long term evolution (LTE) system or an enhanced LTE (LTE-advanced, LTE-A) system, such as a traditional macro base station eNB and a micro base station eNB in ​​a heterogeneous network scenario. Alternatively, it can include a next generation node B (gNB) in a new radio (NR) system. Alternatively, it can include a transmission reception point (TRP), a home base station (for example, a home evolved NodeB, or a home Node B, HNB), a base band unit (BBU), a base band pool (BBU pool), or a wireless fidelity (WiFi) access point (AP), etc. Alternatively, it may include a base station in a non-terrestrial network (NTN), which can be deployed on an aircraft or satellite. In an NTN, the access network device can function as a Layer 1 (L1) relay, a base station, or an integrated access and backhaul (IAB) node. Alternatively, the access network device can be a device that implements base station functions in the IoT, such as drone communications, V2X, D2D, or machine-to-machine (M2M) devices.

[0147] In some possible scenarios, the access network device may also be a module or unit that can implement some of the functions of the base station. For example, the first network device may be a centralized unit (CU), a distributed unit (DU), a CU-control plane (CP), a CU-user plane (UP), or a radio unit (RU). The CU and DU may be set separately, or may be included in the same network element, such as a baseband unit (BBU). The RU may be included in a radio frequency device or radio frequency unit, such as a remote radio unit (RRU), an active antenna unit (AAU), or a remote radio head (RRH).

[0148] In different systems, 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 (open RAN, ORAN) system. In the ORAN system, CU may also be referred to as open (open, O)-CU, DU may also be referred to as O-DU, CU-CP may also be referred to as O-CU-CP, CU-UP may also be referred to as O-CU-UP, and RU may also be referred to as O-RU. Any 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.

[0149] Optionally, the base station in the embodiment of the present 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., and the embodiments of the present application do not make specific limitations on this.

[0150] Optionally, the user plane function network element involved in this application may be a UPF network element of a 5G communication architecture, or a network element with user plane function network element functions in other communication systems. The session management function network element involved in this application may be an SMF network element of a 5G communication architecture, or a network element with session management function network element functions in other communication systems. This application does not limit this.

[0151] The relevant 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 implemented by the communication device 600 in Figure 6. Figure 6 is a structural diagram of the communication device 600 provided in an 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 is only exemplary and is described by taking the communication interface 604 and one processor 601 as an example), and optionally may also include a memory 603.

[0152] The processor 601 can be a general-purpose central processing unit (CPU), a microprocessor, an application-specific integrated circuit (ASIC), or one or more integrated circuits used to control the execution of the program of the present application.

[0153] The communication line 602 may include a path for connecting different components.

[0154] The communication interface 604 may be a transceiver module for communicating with other devices or communication networks, such as Ethernet, RAN, or wireless local area networks (WLAN). For example, the transceiver module may be a device such as a transceiver or a transceiver. Alternatively, the communication interface 604 may be a transceiver circuit within the processor 601, which is used to implement signal input and output to the processor.

[0155] The memory 603 may be a device having 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 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.), a magnetic disk storage medium or other magnetic storage device, or any other medium that can be used to carry or store 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 be independent and connected to the processor via a communication line 602. The memory may also be integrated with the processor.

[0156] The memory 603 is used to store computer-executable instructions for executing the solution of the present application, and the execution is controlled by the processor 601. The processor 601 is used to execute the computer-executable instructions stored in the memory 603, thereby implementing the communication method provided in the embodiment of the present application.

[0157] Alternatively, optionally, in an embodiment of the present application, the processor 601 may also perform processing-related functions in the communication method provided in the following embodiments of the present application, and the communication interface 604 is responsible for communicating with other devices or communication networks, which is not specifically limited in the embodiments of the present application.

[0158] Optionally, the computer-executable instructions in the embodiments of the present application may also be referred to as application code, which is not specifically limited in the embodiments of the present application.

[0159] In a specific implementation, as an embodiment, the processor 601 may include one or more CPUs, such as CPU0 and CPU1 in FIG6 .

[0160] In a specific implementation, as an embodiment, the communication device 600 may include multiple processors, such as the processor 607 and the processor 601 in FIG6 . 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: a central processing unit (CPU), a microprocessor, a digital signal processor (DSP), a microcontroller unit (MCU), or an artificial intelligence processor, etc., and each computing device may include one or more cores for executing software instructions to perform calculations or processing.

[0161] In a specific implementation, as an embodiment, the communication device 600 may further include an output device 605 and an input device 606. The output device 605 communicates with the processor 601 and can display information in a variety of ways. For example, the output device 605 can be a liquid crystal display (LCD), a light emitting diode (LED) display device, a cathode ray tube (CRT) display device, or a projector. The input device 606 communicates with the processor 601 and can receive user input in a variety of ways. For example, the input device 506 can be a mouse, a keyboard, a touch screen device, or a sensor device.

[0162] The communication device 600 described above may also sometimes be referred to as a communication device, and may be a general-purpose device or a dedicated device. For example, the communication device 600 may be a desktop computer, a portable 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 similar structure to that shown in FIG6 . The embodiments of the present application do not limit the type of the communication device 600.

[0163] In addition, the composition structure shown in FIG6 does not constitute a limitation on the communication device. In addition to the components shown in FIG6, the communication device may include more or fewer components than shown in the figure, or combine certain components, or arrange the components differently.

[0164] The communication method provided in the embodiment of the present application is described below in conjunction with the communication system shown in Figure 3 or Figure 4.

[0165] It should be noted that in the following embodiments of the present application, the message names, parameter names, or information names between network elements are only examples. In other embodiments, they may also be other names. The communication method provided in this application does not make specific limitations on this.

[0166] It is understood that in the embodiments of the present application, each network element may perform some or all of the steps in the embodiments of the present application. These steps or operations are merely examples, and the embodiments of the present application may also perform other operations or variations of various operations. In addition, the steps may be performed in a different order than those presented in the embodiments of the present application, and it is possible that not all operations in the embodiments of the present application need to be performed.

[0167] FIG7 is a schematic diagram of an example of a communication method provided in an embodiment of the present application. The method can be applied to the communication system shown in FIG3. The method is described by taking the interaction between 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 subject that performs the session management function network element action in the method can also be a device / module in the session management function network element, such as a chip, processor, or processing unit in the session management function network element; the subject that performs the user plane function network element action in the method can also be a device / module in the user plane function network element, such as a chip, processor, or processing unit in the user plane function network element; the subject that performs the access network device action in the method can also be a device / module in the access network device, such as a chip, processor, or processing unit in the access network device; the subject that performs the first terminal device action in the method can also be a device / module in the first terminal device, such as a chip, processor, or processing unit in the first terminal device; the subject that performs the second terminal device action in the method can also be a device / module in the second terminal device, such as a chip, processor, or processing unit in the second terminal device, and the embodiments of the present application do not specifically limit this. In the embodiments of the present application, the processing performed by a single execution entity (for example, an access network device, a first terminal device, or a second terminal device) may also be divided into multiple execution entities, which may be logically and / or physically separated. For example, as shown in FIG7 , method 700 includes the following steps:

[0168] 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.

[0169] In an embodiment of the present application, the first indication information is used to instruct the access network device to add the first information to the first PDU Set. Exemplarily, the first indication information is used to instruct the access network device to add the first information to the first PDU Set sent to the first terminal device. In an embodiment of the present application, the first information is used by the first terminal device to process a data packet of the first PDU Set according to the first information when sending the first PDU Set to the second terminal device.

[0170] In an embodiment of the present application, the first indication information may 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 in the first PDU Set according to the pre-configuration. If the first indication information is pre-configured in the access network device, step S710 is optional.

[0171] 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 in the first PDU Set. For example, if the specially configured 5QI is configured by the operator and the value of the specially configured 5QI is "200", it may instruct the access network device to add the first indication information in the first PDU Set.

[0172] In one possible implementation, the first indication information is only used to instruct the access network device to add the first information in the first PDU Set, and the access network device determines which data packet or 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 of 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 other partial data packets of 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 sequence numbers; or, optionally, the access network device adds the first information to 10 data packets with odd sequence 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 packet 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 are not limited to this.

[0173] In another possible implementation, the first indication information is used to instruct the access network device to which data packet or packets of the first PDU Set to add the first information. Optionally, the first indication information is used to instruct the access network device to add the first information to the first packet of the first PDU Set; or, optionally, the first indication information is used to instruct the access network device to add the first information to each data packet of the first PDU Set; or, optionally, the first indication information is used to instruct the access network device to add the first information to the first packet and other partial data packets of the first PDU Set. For example, the first PDU Set includes 20 data packets, and the first indication information is used to instruct the access network device to add the first information to the first 10 data packets; or, optionally, the first indication information is used to instruct the access network device to add the first information to the first packet and the 10 data packets with even numbers; or, optionally, the first indication information is used to instruct the access network device to add the first information to the 10 data packets with odd numbers; or, optionally, the first indication information is used to instruct the access network device to add the first information to the first packet and other random data packets; or, optionally, the first indication information is used to instruct the access network device to add the first information to the data packets of the first PDU Set according to other rules, which is not limited in this embodiment of the present application.

[0174] It should be noted that adding the first information in the first packet can ensure that the method of the embodiment of the present application achieves better technical effects. The solution of not adding the first information in the first packet can also be within the protection scope of the embodiment of the present application. The embodiment of the present application is introduced by adding the first information in the first packet. It should be noted that the first packet of the first PDU Set can usually be received.

[0175] Optionally, in an embodiment of the present application, the first indication information is sent by the session management function network element to the access network device based on the connection between the first terminal device and the second terminal device; or, optionally, the first indication information is sent by the policy control function network element to the access network device based on the connection between the first terminal device and the second terminal device; or, optionally, the first indication information is sent by the session management function network element to the access network device based on other information, such as the session management network element is determined based on information provided by the third-party application side through the policy control network element. This embodiment of the present application does not limit this.

[0176] Exemplarily, the first terminal device is the relay terminal device introduced in related technology 2, such as a mobile phone; the second terminal device is the remote terminal device introduced in related technology 2, such as AR glasses.

[0177] S720: The user plane function network element sends one or more data packets of the first PDU Set to the access network device. Correspondingly, the access network device receives one or more data packets of the first PDU Set from the user plane function network element.

[0178] In an embodiment of the present application, one or more data packets of the first PDU Set sent by the user plane functional network element to the access network device include the first PDU Set information. Please refer to the relevant description of related technology 4 and will not repeat it here.

[0179] Optionally, in an embodiment of the present application, the one or more data packets of the first PDU Set sent by the user plane functional network element to the access network device include data packets that the user plane functional network element is currently sending to the access network device and data packets received by the access network device from the user plane functional network element. Exemplarily, the data packets of the first PDU Set sent by the user plane functional network element to the access network device are data packets 1 to data packets 10 (the following examples all assume that the data packets of the first PDU Set are sent in ascending order of data packet sequence numbers, which will not be repeated here), the data packets of the first PDU Set received by the access network device from the user plane functional network element are data packets 1 to data packets 8, and data packets 9-10 are in the process of being transmitted.

[0180] Through the above example, it can be understood that the one or more data packets of the first PDU Set sent by the user plane functional network element to the access network device are not equivalent to the one or more data packets of the first PDU Set received by the access network device from the user plane functional network element. Similarly, the 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 the one or more data packets received by the first terminal device from the access network device. This is explained uniformly here and will not be repeated.

[0181] Under normal circumstances, no packet loss occurs when the user plane functional network element sends the first PDU Set data packet to the access network device. Therefore, the embodiment of the present application does not provide a detailed introduction to the situation where packet loss occurs when the user plane functional network element sends the first PDU Set data packet to the access network device.

[0182] 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.

[0183] In an embodiment 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 part 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 will 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 data packets 10, and the access network device gradually sends one or more data packets of the first PDU Set to the first terminal device, such as sending data packets 1 to data packets 8 at time 1 (this example assumes 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 first information described below, or may not carry the sequence number information, and the access network device sends 8 data packets of the first PDU Set to the first terminal device), and sends data packets 9-10 at the subsequent time 2. 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 data packets of the received one or more data packets of the first PDU Set to the first terminal device.

[0184] In an embodiment of the present application, at least one of the one or more data packets of a first PDU Set sent by an access network device to a first terminal device carries first information, and the first information carried in the at least one data packet is added by the access network device based on the first indication information. Accordingly, 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, wherein the one or more data packets belong to the first PDU Set.

[0185] Optionally, in an embodiment of the present application, the first information is carried in a header of a data packet; optionally, the first information is carried in other locations of the data packet, which is not limited in the embodiment of the present application. Exemplarily, the first information can be carried in the PDCP layer or the service data adaptation protocol (SDAP) layer of the downlink data packet, which is not limited in the embodiment of the present application.

[0186] It should be noted that one or more data packets of the first PDU Set sent by the user plane functional 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, and the data packet of the first PDU Set sent by the first terminal device to the second terminal device in the following step S750 does not carry the first information. Since the identifier of the first PDU Set transmitted in the three processes, for example, the serial number information of the first PDU Set is the same, the first PDU Set in the three processes can be considered to be the same first PDU Set.

[0187] Of course, the first PDU Set data packet sent by the user plane functional network element to the access network device carries the first PDU Set information. The first PDU Set information is used by the access network device to determine which data packets in the QoS flow belong to the first PDU Set, or in other words, the first PDU Set information is used by the user plane functional network element to send the first PDU Set to the access network device. In the embodiment of the present application, the first information is different from the first PDU Set information, or in other words, the first information and the first PDU Set information have different functions, and the first information is used by the first terminal device to send the first PDU Set to the second terminal device.

[0188] The embodiment of the present application lists the information that the first information may include, and the following embodiment will provide a detailed introduction to each information in the corresponding steps.

[0189] The first information may include: sequence number information of the first PDU Set, sequence number information of each data packet in the first PDU Set, importance information of the first PDU Set, indication information of the last data packet in the first PDU Set, a first delay, second indication information, etc. The aforementioned information may be determined by the access network device and added to at least one data packet in the first PDU Set.

[0190] S740: The first terminal device processes the data packet of the first PDU Set according to the first information.

[0191] In an embodiment of the present application, the first terminal device processing the data packets of the first PDU Set according to the first information may include: the first terminal device determining that one or more data packets received from the access network device belong to the first PDU Set according to the first information; or, the first terminal device processing the data packets of the first PDU Set according to the first information may also include: the first terminal device determining whether to send the data packets of the first PDU Set to the second terminal device according to the first information. Alternatively, the first terminal device processing the data packets of the first PDU Set according to the first information may include: the first terminal device first determines that one or more data packets received from the access network device belong to the first PDU Set according to the first information, and then determines whether to send the data packets belonging to the first PDU Set to the second terminal device according to the first information. The following embodiments will be introduced respectively.

[0192] 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.

[0193] In an embodiment of the present application, a first terminal device processes a data packet of a first PDU Set based on first information, including: the first terminal device determining that one or more data packets received from an access network device belong to the first PDU Set based on at least one of 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. This solution enables the first terminal device to send the one or more received data packets belonging to the first PDU Set to a second terminal device, thereby preparing for transmission at PDU Set granularity.

[0194] Exemplarily, the first terminal device determines that the received data packet belongs to the first PDU Set based on the sequence number information of the first PDU Set included in the first information in the received data packet.

[0195] It should be noted that if the first terminal device also processes other PDU Sets while processing the first PDU Set, each of 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.

[0196] Exemplarily, the first terminal device determines that the received data packet belongs to the first PDU Set based on the indication information of the last data packet in the first PDU Set included in the first information in the received data packet, and that the 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 packet before the data packet belongs to the first PDU Set based on the indication information of the last data packet in the first PDU Set included in the data packet received from the access network device.

[0197] Alternatively, as a possible implementation method, the first terminal device determines that one or more data packets received from the access network device belong to the first PDU Set based on 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 based on the fact that the PDU Set currently being processed by the first terminal device is only the first PDU Set.

[0198] It should be noted that, in the description of the following embodiments, the first terminal device receiving one or more data packets from the access network device is described as the first terminal device receiving one or more data packets of the first PDU Set from the access network device.

[0199] In the embodiment of the present application, the first terminal device determines whether to send the data packet of the first PDU Set to the second terminal device according to the first information. Alternatively, the first terminal device sends the data packet 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 packet 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 packet of the first PDU Set to the second terminal device according to the first information. This embodiment of the present application does not limit this.

[0200] In the embodiment of the present application, the first terminal device sending the data packets of the first PDU Set to the second terminal device may be that the first terminal device sends the data packets of the first PDU Set to the second terminal device in sequence. In layman's terms, not all data packets of the first PDU Set are sent instantly. The first terminal device not sending the data packets of the first PDU Set to the second terminal device may be that the first terminal device does not send any data packet of the first PDU Set to the second terminal device, or, after sending one or more data packets of the first PDU Set to the second terminal device, the first terminal device does not send the data packets of the first PDU Set that have not yet been sent to the second terminal to the second terminal.

[0201] Optionally, the first information includes a first delay. In an embodiment of the present application, the first delay is used to indicate a transmission delay budget for the first PDU Set from the first terminal device to the second terminal device, that is, an upper limit of the transmission delay required from the first terminal device receiving the first data packet of the first PDU Set to sending the first PDU Set to the second terminal device.

[0202] In this embodiment of the present application, the first delay is determined based on 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 represent the transmission delay budget of the first PDU Set. For a description of the PSDB of the first PDU Set, please refer to the relevant description in Related Art 4 and will not be repeated here. This solution allows the access network device to determine the first delay based on the transmission time of the first PDU Set.

[0203] For example, the time when the access network device receives the first data packet of the first PDU Set from the user plane functional network element is t0, the time 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 delay is t-(t1-t0), where the PSDB of the first PDU Set is the RAN device PSDB introduced in related technology 4 at this time.

[0204] In one 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 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 the one or more data packets of the first PDU Set can be sent to the second terminal device within the first delay.

[0205] In an embodiment of the present application, one or more data packets of the first PDU Set received by the first terminal device from the access network device meet the first delay, which can ensure that there is a remaining transmission delay budget within the first 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.

[0206] Exemplarily, the first delay is 20ms, the first PDU Set includes 20 data packets, the transmission delay budget of each data packet of the first PDU Set from the first terminal device to the second terminal device is 10ms, the one or more data packets received by the first terminal device from the access network device are data packets 1-data packet 10, and the data packets sent by the first terminal device to the second terminal device at the same time are data packets 1-data packet 5, that is, the first terminal device has spent a delay of 10ms to send data packets 1-data packet 5 to the second terminal device, and the remaining first delay is 10ms. The first terminal device determines to send data packets 6-data packet 10 to the second terminal device based on the remaining delay budget of 10ms for data packets 6-data packet 10 (greater than or equal to the delay budget for data packets 6-data packet 10, that is, 10ms).

[0207] Optionally, if there is no remaining transmission delay budget within the first delay, the first terminal device does not send, to the second terminal device, the data packet that has not yet been sent among the one or more data packets received from the access network device.

[0208] Optionally, the access network device adds a first 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 delay. The first terminal device sends or does not send to the second terminal device the data packet that has not been sent among the one or more data packets received from the access network device based on the first delay and the transmission delay budget remaining within the current first delay (for example, the second data packet of the first PDU Set received by the first terminal device carries the first delay, the first terminal device determines the transmission delay budget remaining within the current first delay based on the delay of 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 based on the remaining transmission delay budget).

[0209] Optionally, the access network device adds an updated first delay in the process of sending one or more data packets of the first PDU Set to the first terminal device, that is, the first delay may change during the transmission of one or more data packets of the first PDU Set; the first terminal device receives a data packet from the access network device carrying the first delay, 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 is calculated from the receipt of the data packet carrying the first delay, and it is necessary to ensure that the data packet in the subsequent first PDU Set is transmitted to the second terminal device side within the first delay. Alternatively, the above-mentioned updated first delay can 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 a first delay to 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 to other data packets sent to the first terminal device except the first packet. The first terminal device sends the data packet to the second terminal device or not 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 the data packet to the second terminal device or not according to the remaining transmission delay budget within the first delay carried in the data packet.

[0210] Optionally, the first information includes a transmission delay budget for each data packet in the first PDU Set determined by the first delay, where the transmission delay budget for each data packet is a transmission delay budget for the data packet from the first terminal device to the second terminal device. For example, if the first delay is 20 ms, the first PDU Set includes 20 data packets, and the transmission delay budget for each data packet in the first PDU Set is 9 ms.

[0211] The following introduces two scenarios in which the access network device determines to send or not send the first PDU Set data packet to the first terminal device based on the packet loss situation.

[0212] Case 1:

[0213] For PDU Set processing scenario 1 or 2 in related technology 6, if packet loss occurs during the process of the access network device sending the first PDU Set data packet to the first terminal device, the access network device determines not to send the first PDU Set data packet to the first terminal device. If packet loss does not occur during the process of the access network device sending the first PDU Set data packet to the first terminal device, the access network device determines to send the first PDU Set data packet to the first terminal device.

[0214] Case 2:

[0215] For the third processing scenario of PDU Set in related technology 6, if the cumulative number of packet losses occurring in the process of the access network device sending the first PDU Set data packet to the first terminal device is greater than the first threshold, the access network device determines not to send the first PDU Set data packet to the first terminal device.

[0216] If the cumulative 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 is less than or equal to a first threshold, the access network device determines to send the data packets of the first PDU Set to the first terminal device. Alternatively, when the access network device sends the first PDU Set to the first terminal device, it needs to ensure that the number of packet losses that occur during the transmission of the data packets of the first PDU Set is within the first threshold.

[0217] In the above situation 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 packet losses that the first PDU Set can tolerate.

[0218] It should be noted that the access network device does not perceive whether packet loss occurs in the process of the first terminal device sending the first PDU Set to the second terminal device.

[0219] In an embodiment of the present application, the access network device does not send the data packet of the first PDU Set to the first terminal device, which may be that the access network device does not send the data packet in the first PDU Set that has not been sent, or the data packet that has not been successfully sent, to the first terminal device; the access network device sends the data packet of the first PDU Set to the first terminal device, which may be that the access network device sends the data packet in the first PDU Set that has not been sent, or the data packet that has not been successfully sent, to the first terminal device. The following introduces two scenarios in which the first terminal device determines whether to send or not to send the data packet of the first PDU Set to the second terminal device based on 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.

[0220] Case 3:

[0221] For processing scenario one or processing scenario two of the PDU Set in related technology 6, if packet loss occurs in 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 in 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.

[0222] It should be noted that, corresponding to the above-mentioned situation one, 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 perceive whether packet loss occurs in 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 occurred in the process of the access network device sending the first PDU Set to the first terminal device based on the fact that no data packet of the first PDU Set is subsequently received from the access network device. 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, and the indication information is used to instruct the first terminal device not to 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 occurred in 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 occurred in 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 an identifier of the first PDU Set, such as the sequence number information of the PDU Set.

[0223] If no packet loss occurs when the first terminal device sends the first PDU Set to the second terminal device, and no packet loss occurs when the access network device sends 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.

[0224] It should be noted that, corresponding to the above-mentioned situation one, the first terminal device can determine that no packet loss occurs in the process of the access network device sending the first PDU Set data packet to the first terminal device based on the fact that the first PDU Set data packet can always be received from the access network device. It should be noted that the embodiment of the present application is based on the access network device sending information (for example, the second indication information described below) to the first terminal device through the data packet. The situation where the access network device sends information to the first terminal device through the control information is not described in detail in the embodiment of the present application.

[0225] Case 4:

[0226] For the third processing scenario of PDU Set in related technology 6, if the first terminal device determines that the sum of the number of packet losses that occurred in the process of the first terminal device sending the first PDU Set data packet to the second terminal device and the number of packet losses that occurred in the process of the access network device sending the first PDU Set data packet to the first terminal device is greater than the first threshold, the first terminal device determines not to send the first PDU Set data packet to the second terminal device. Wherein, packet loss may not occur in the process of the access network device sending the first PDU Set data packet to the first terminal device, and packet loss may not occur in the process of the first terminal device sending the first PDU Set data packet to the second terminal device, and accordingly, the number of packet losses can be considered to be 0.

[0227] If the first terminal device determines that the sum of the number of packet losses that occur when the first terminal device sends the first PDU Set data packet to the second terminal device and the number of packet losses that occur when the access network device sends the first PDU Set data packet to the first terminal device is less than or equal to the first threshold, the first terminal device determines to send the first PDU Set data packet to the second terminal device.

[0228] In an embodiment of the present application, the first terminal device does not send the data packet of the first PDU Set to the second terminal device, which may be that the first terminal device does not send the data packet in the first PDU Set that has not been sent, or the data packet that has not been successfully sent to the second terminal device; the first terminal device sends the data packet of the first PDU Set to the second terminal device, which may be that the first terminal device sends the data packet in the first PDU Set that has not been sent, or the data packet that has not been successfully sent to the second terminal device.

[0229] Optionally, as shown in FIG7 , the communication method provided in the embodiment of the present application further includes:

[0230] 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.

[0231] In an embodiment 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.

[0232] In an embodiment of the present application, the access network device sends second indication information to the first terminal device via a data packet. For example, corresponding to scenario four, the access network device adds the second indication information to a data packet sent to the first terminal device after the data packet in which the packet loss occurred. Optionally, the first information includes the second indication information; alternatively, the second indication information is separate information within the data packet, which is not limited in this embodiment of the present application.

[0233] Or, exemplarily, corresponding to situation three, 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 embodiment of the present application will not be described in detail, and steps S750 and S760 are mainly explained around situation four.

[0234] S760: The first terminal device determines not to send the data packet of the first PDU Set to the second terminal device based on the second indication information.

[0235] In an embodiment of the present application, the first terminal device determines not to send a data packet of the first PDU Set to the second terminal device based on the second indication information. Alternatively, in an embodiment of the present application, before the first terminal device determines not to send a data packet of the first PDU Set to the second terminal device based on the second indication information, the first terminal device first determines not to send a data packet of the first PDU Set to the second terminal device based on the second indication information.

[0236] In an embodiment of the present application, the first terminal device determines not to send data packets of the first PDU Set to the second terminal device based on the second indication information. This can be done by the first terminal device determining not to send data packets in the first PDU Set that have not yet been sent to the second terminal device based on the second indication information. This solution can enable the first terminal device to determine not to send data packets in the first PDU Set that have not yet been sent to the second terminal device based on the second indication information, thereby avoiding the waste of transmission resources caused by still sending data packets of the first PDU Set to the second terminal device even if packet loss occurs and the first PDU Set cannot be correctly decoded.

[0237] In one possible implementation, the second indication information is also used to indicate the second packet loss number in the first PDU Set, where the second packet loss number is the number of data packets that have been lost in the process of the access network device sending the data packets of the first PDU Set to the first terminal device, as determined by the access network device.

[0238] Optionally, each time packet loss occurs during the process of the access network device sending a data packet of the first PDU Set to the first terminal device, the access network device sends an updated second packet loss number to the terminal device. For example, when the access network device sends a data packet of the first PDU Set to the first terminal device, packet loss occurs for the first time, and the second packet loss number indicated by the second indication information is 1. When the access network device sends a data packet of the first PDU Set to the first terminal device, packet loss occurs for the second time, and the second packet loss number indicated by the second indication information is 2. And so on. That is, the second packet loss number indicated by the second indication information is notified to the first terminal device in the form of an increment, which will not be repeated here.

[0239] Optionally, every time n packet losses occur during the process of the access network device sending the first PDU Set data packet to the first terminal device, the access network device sends an updated second packet loss number to the terminal device. For example, if the fifth packet loss occurs during the process of the access network device sending the first PDU Set data packet to the first terminal device, the access network device sends a second indication message to the first terminal device, and the second packet loss number indicated by the second indication message is 5. If the tenth packet loss occurs during the process of the access network device sending the first PDU Set data packet to the first terminal device, the access network device sends a second indication message to the first terminal device, and the second packet loss number indicated by the second indication message is 10, and so on, which will not be repeated here.

[0240] In one 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 number, wherein the first difference is the number of redundant data packets remaining within the first threshold or the upper limit of redundant data packets for transmitting the first PDU Set. The description of updating the first difference can refer to the description of updating the second packet loss number described above. For example, the first difference can be updated once each packet loss occurs, or once every n packet losses occur. The details are not repeated here.

[0241] In one possible implementation, the second indication information is also used to indicate the first redundant packet ratio, which 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 the number of packet losses is within the first redundant ratio during the transmission of the first PDU Set. Among them, 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 once each time a packet loss occurs, or the first redundant packet ratio can be updated once every n packet losses occur. No further details will be given here.

[0242] In an embodiment of the present application, the first terminal device determines not to send the data packet of the first PDU Set to the second terminal device based on the second indication information in the above-mentioned possible implementation methods.

[0243] Alternatively, as a possible implementation, the policy control function network element or the session management function network element may determine the second threshold and the third threshold based on information provided by the application function network element or preconfigured information. 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 value, ensuring that the number or proportion of packet loss occurring in 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 value, or the access network device determines not to send the data packets of the first PDU Set to the first terminal device based on the number of packet loss occurring in 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 value; similarly, the first terminal device sends the data packets of the first PDU Set to the second terminal device based on the third threshold value, ensuring that the number or proportion of packet loss occurring in 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 value, or the first terminal device determines not to send the data packets of the first PDU Set to the second terminal device based on the number of packet loss occurring in 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 value.

[0244] Optionally, the embodiment described in FIG7 is illustrated by taking the case where the second indication information is not carried in the first information as an example. Of course, as described above, the second indication information may also be carried in the first information. In this case, the above steps S750 and S760 are not performed. Step S740 is that the first terminal device processes the data packet of the first PDU Set according to the first information, including: the first terminal device determines whether to send the data packet of the first PDU Set to the second terminal device according to the first information, and further, the first terminal device determines not to send the data packet of the first PDU Set to the second terminal device according to the second indication information. For related descriptions, please refer to the description of step S760, which will not be repeated here.

[0245] In one possible implementation, S760 specifically includes:

[0246] S761, the first terminal device determines the current accumulated number of first packet losses based on the number of received second indication information.

[0247] In an embodiment of the present application, the first packet loss number includes the number of packet losses that occur when the access network device sends the first PDU Set data packet to the first terminal device, and / or the number of packet losses that occur when the first terminal device sends the first PDU Set data packet to the second terminal device.

[0248] It should be noted that, in S761, the first number of packet losses is determined by the first terminal device, and the second number of packet losses indicated by the second indication information in the above S750 is determined by the access network device.

[0249] S762: When the first packet loss number is greater than the first threshold, the first terminal device determines not to send the data packet of the first PDU Set to the second terminal device.

[0250] In a possible implementation, the first packet loss number is greater than the first threshold by 1, and the first terminal device determines not to send the data packet of the first PDU Set to the second terminal device.

[0251] For example, the number of second indication messages received by the first terminal device is 5, the number of packet losses that occur during the process of the first terminal device sending data packets of the first PDU Set to the first terminal device is 5, and the first threshold is 9. The first terminal device determines not to send data packets of the first PDU Set to the second terminal device based on the first packet loss number being 10, which is greater than the first threshold 9. This solution allows the first terminal device to determine not to send data packets in the first PDU Set that have not yet been sent to the second terminal device based on the cumulative first packet loss number exceeding the first threshold, thereby avoiding the waste of transmission resources caused by still sending data packets of the first PDU Set to the second terminal device when the first packet loss number exceeds the first threshold and the first PDU Set cannot be correctly decoded.

[0252] Alternatively, as a possible implementation method, packet loss occurs during the process of the access network device sending 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 loss occurs during the process of the access network device sending data packets of the first PDU Set to the first terminal device based on the discontinuous sequence numbers of the multiple data packets of the first PDU Set received from the access network device. Furthermore, the first terminal device determines the current accumulated first packet loss number based on the number of discontinuous sequence numbers of the multiple data packets received from the access network device, and then, when the first packet loss number is greater than the first threshold, the first terminal device determines not to send data packets of the first PDU Set to the second terminal device. This implementation method is based on the first information including the sequence number information of each data packet of the first PDU Set.

[0253] It should be noted that, in the embodiment of the present application, for each data packet carrying the first information in one or more data packets of the first PDU Set sent by the access network device to the first terminal device, the first information carried may be different, so that the scheme in the above possible implementation method can be implemented. For example, the first packet of the first PDU Set sent by the access network device to the first terminal device carries the first delay, or each data packet of the first PDU Set sent by the access network device to the first terminal device except the first packet carries the remaining delay budget within the first delay, or each data packet of the first PDU Set sent by the access network device to the first terminal device carries the sequence number information of the data packet, or each data packet of the first PDU Set sent by the access network device to the first terminal device carries the sequence number information of the first PDU Set, or the last data packet of the first PDU Set sent by the access network device to the first terminal device carries the indication information of the last data packet of the first PDU Set. The embodiment of the present application does not limit this.

[0254] Regarding the communication method shown in FIG. 7 , in one possible implementation, although not shown, the communication method provided in the embodiment of the present application further includes:

[0255] S770, the access network device determines the first information according to the transmission status of the data packet of the first PDU Set sent to the first terminal device.

[0256] For example, when the first information includes the second indication information, the access network device determines the first information based on packet loss occurring during the process of sending the first PDU Set to the first terminal device; 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 based on the remaining transmission delay budget within the first delay during the process of sending the data packet 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 packet of the first PDU Set that the access network device has not yet sent to the first terminal device, that is, the access network device determines the first information carried in the data packet of the first PDU Set that the access network device has not yet sent to the first terminal device based on the transmission status of the data packet of the first PDU Set that has been sent to the first terminal device. For other examples of the access network device determining the first information carried in the data packet of the first PDU Set that the access network device has not yet sent to the first terminal device based on the transmission status of the data packet of the first PDU Set sent to the first terminal device, please refer to the description of various corresponding possible implementation methods in the above embodiments, and will not be repeated here.

[0257] In the communication method provided by an embodiment of the present application, an 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 a first terminal device based on first indication information received from a session management function network element that instructs the access network device to add the first information in the first PDU Set, so that the first terminal device determines whether to send a data packet of the first PDU Set to a second terminal device based on 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 cascade scenario, i.e., the first terminal device, to obtain the transmission status of the first PDU Set and transmit the first PDU Set accordingly based on the first information.

[0258] Figure 8 is a schematic diagram of another example of a communication method provided in an embodiment of the present application. The method can be applied to the communication system shown in Figure 4. The method is 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 subject that executes the user plane function network element action in the method can also be a device / module in the user plane function network element, such as a chip, processor, processing unit, etc. in the user plane function network element; the subject that executes the source access network device action in the method can also be a device / module in the source access network device, such as a chip, processor, processing unit, etc. in the source access network device; the subject that executes the target access network device action in the method can also be a device / module in the target access network device, such as a chip, processor, processing unit, etc. in the target access network device; the subject that executes the terminal device action in the method can also be a device / module in the terminal device, such as a chip, processor, processing unit, etc. in the terminal device, and the embodiment of the present application does not specifically limit this. In the embodiment of the present application, the processing performed by a single execution entity (for example, a user plane function network element, a source access network device, a target access network device, and a terminal device) may also be divided into multiple execution entities, which may be logically and / or physically separated. For example, as shown in FIG8 , method 800 includes:

[0259] 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.

[0260] In an embodiment of the present application, the first PDU Set sent by the user plane functional network element to the source access network device carries the first PDU Set information. For the first PDU Set information, please refer to the relevant description in related technology 4 and will not be repeated here.

[0261] In an embodiment of the present application, the user plane functional network element sending the first PDU Set to the source access network device can be the user plane functional network element sending a data packet of the first PDU Set to the source access network device. Regarding the user plane functional network element sending the data packet of the first PDU Set to the source access network device, reference can be made to the relevant description of S720 user plane functional network element sending one or more data packets of the first PDU Set to the access network device. This embodiment of the present application does not provide a detailed description of this.

[0262] S820: The source access network device sends a portion of the data packets of the first PDU Set to the terminal device. Correspondingly, the terminal device receives the portion of the data packets of the first PDU Set from the source access network device.

[0263] 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 equivalent to some data packets of the first PDU Set received by the terminal device from the source access network device. For the relevant description of some data packets of the first PDU Set sent by the source access network device to the terminal device being not equivalent to some data packets of the first PDU Set received by the terminal device from the source access network device, reference can be made to the relevant description of one or more data packets of the first PDU Set sent by the user plane functional network element to the access network device being not equivalent to one or more data packets of the first PDU Set received by the access network device from the network element in S720, which will not be repeated here.

[0264] It should be noted that the partial 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, wherein the data packets that have been transmitted include at least one of data packets received by the terminal device or data packets that have been lost. The source access network device may determine that data packets have been lost according to the method described in Related Technology 5 above.

[0265] S830: When the terminal device switches to the target access network device, the source access network device sends the untransmitted data packets in the first PDU Set to the target access network device. Correspondingly, the target access network device receives one or more data packets from the source access network device.

[0266] In one possible implementation, the data packets that have not yet been transmitted in the first PDU Set sent by the source access network device to the target access network also include the data packets that failed to be sent by the source access network device to the terminal device, and at least one of the partial data packets that the source access network device is currently sending to the terminal device, thereby improving the success rate of transmission of the first PDU Set, which is not limited here.

[0267] In one possible implementation, if the packet loss of the already transmitted data packets in the partial data packets 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 data packets in the first PDU Set that have not yet been transmitted to the target access network device. In this solution, the source access network device sends the data packets in the first PDU Set that have not yet been transmitted to the target access network device when it determines that the already transmitted data packets in the partial data packets of the first PDU Set currently sent to the terminal device can ensure the correct decoding of the first PDU Set, thereby avoiding the waste of transmission resources caused by sending the data packets in the first PDU Set that have not yet been transmitted to the target access network device even if the first PDU Set cannot be correctly decoded.

[0268] Optionally, the first condition is that no packet loss occurs. In an embodiment of the present application, if the data packets that have been transmitted in some of the data packets of the first PDU Set sent by the source access network device to the terminal device are lost, which will cause the first PDU Set to be unable to be correctly decoded as described in the processing scenario one and the processing scenario two in the related technology 6, 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 when no packet loss occurs. In this scheme, 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 data packets that have been transmitted in some of the data packets of the first PDU Set currently sent to the terminal device have not been lost. When it is ensured that the data packets that have not been transmitted in the first PDU Set are sent to the target access network device when the first PDU Set is correctly decoded, the data packets that have not been transmitted in the first PDU Set are sent to the target access network device, thereby avoiding the waste of transmission resources caused by 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] Optionally, the first condition is that the number of packet losses is less than or equal to the number of redundant data packets corresponding to the first PDU Set. In an embodiment of the present application, if the number of packet losses of the data packets that have been transmitted and are lost in some of the 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, which will cause the first PDU Set to be unable to be correctly decoded as described in the processing scenario three in the related technology 6, 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 when the number of packet losses is less than or equal to the maximum number of redundant packets of the first PDU Set. The maximum number of redundant packets of the first PDU Set is the number of redundant packets configured by the session management function network element for the first PDU Set. In this scheme, 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 data packets among the data packets that have been transmitted in 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. When it is ensured that the first PDU Set is correctly decoded, the data packets that have not been transmitted in the first PDU Set are sent to the target access network device, avoiding the waste of transmission resources caused by 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.

[0270] In an embodiment of the present application, the untransmitted data packets 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 the 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 packets 1-10. After the terminal device switches to the target access network device, the untransmitted data packets in the first PDU Set are data packets 11-20.

[0271] Similarly, the data packets that have not yet 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. Please refer to the description in S720 and will not repeat them here.

[0272] In an embodiment of the present application, at least one data packet among the data packets that have not yet been 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 the 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 that have not yet been 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 that have not yet been transmitted in the first PDU Set; or, optionally, the at least one data packet carrying the first information is the first packet and part of the data packets among the data packets that have not yet been transmitted in the first PDU Set. The manner in which the first information is carried in at least one data packet among the data packets that have not yet been transmitted in the first PDU Set sent by the source access network device to the target access network device can refer to the description of the manner in which the first information is carried in at least one data packet among the one or more data packets of the first PDU Set sent by the access network device to the first terminal device in S730, and will not be repeated here.

[0273] The embodiment of the present application lists the information that the first information may include, and the following embodiment will provide a detailed introduction to each information in the corresponding steps.

[0274] The first information may include: sequence number information of the first PDU Set, sequence number information of each data packet in the first PDU Set, importance information of the first PDU Set, indication information of the last data packet in the first PDU Set, a first latency, a first redundant packet ratio, etc. The above-mentioned various possible information is determined by the source access network device and added to at least one data packet among the data packets in the first PDU Set that have not yet been transmitted and sent to the target access network device.

[0275] S840: The target access network device processes one or more data packets from the source access network device according to the first information.

[0276] In an embodiment of the present application, the target access network device processing one or more data packets from the source access network device according to the first information may include the target access network device determining that the one or more data packets received from the source access network device belong to the first PDU Set according to the first information, and the target access network device processing the first PDU Set according to the first information may also include the target access network device determining 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. 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 the target access network device first determining that the one or more data packets received from the source access network device belong to the first PDU Set according to the first information, and then determining whether to send one or more data packets from the source access network device belonging to the first PDU Set to the terminal device according to the first information. The following embodiments will be introduced respectively.

[0277] 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.

[0278] In an embodiment of the present application, a target access network device processes one or more data packets from a source access network device based on first information, including: the target access network device determines that the one or more data packets received from the source access network device belong to the first PDU Set based on 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 indication information of the last data packet in the first PDU Set. This solution enables the target access network device to send the one or more received data packets belonging to the first PDU Set to a terminal device, thereby implementing transmission processing at the PDU Set granularity.

[0279] In an embodiment of the present application, regarding the relevant description of the target access network device determining that one or more received data packets belong to the first PDU Set based on 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, you can refer to the relevant description of the first terminal device determining that one or more received data packets belong to the first PDU Set based on 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 in S730, which will not be repeated here.

[0280] It should be noted that the following embodiments are described with the one or more data packets from the source access network device being one or more data packets of the first PDU Set from the source access network device.

[0281] In an embodiment of the present application, the target access network device determines whether to send one or more data packets from the source access network device to the terminal device based on the first information. This can be the target access network device sending one or more data packets from the source access network device to the terminal device based on the first information, or the target access network device not sending one or more data packets from the source access network device to the terminal device based on the first information. Alternatively, before the target access network device sends or does not send the one or more data packets from the source access network device to the terminal device based on the first information, the target access network device first determines whether to send the one or more data packets from the source access network device to the terminal device based on the first information.

[0282] In an embodiment of the present application, the first information is used to transmit data packets that have not yet been transmitted in the first PDU Set. In other words, the first information is used by the target access network device to determine whether to send one or more data packets among the data packets that have not yet been transmitted in the first PDU Set received from the source access network device to the terminal device.

[0283] It should be noted that, for the sake of clarity of description, the data packets that have not been transmitted in the first PDU Set are only used to represent 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 before the terminal device switches to the target access network. For the partial data packets of the first PDU Set sent by the source access network device to the terminal device, in the following optional steps, the data packets that have been lost or the data packets being transmitted in this part of the data packets are connected with the data packets that have not been transmitted in the first PDU Set and sent from the source access network device to the target access network device, and the target access network device resends them to the terminal device. In the embodiment 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 listed as within the scope of the data packets that have not been transmitted in the first PDU Set.

[0284] Optionally, the first information includes a first delay, which 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 first terminal device receiving the first data packet of the first PDU Set to sending the first PDU Set to the second terminal device.

[0285] In this embodiment of the present application, the first delay is determined based on the PSDB of the first PDU Set, including: the first delay information is determined based on 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; 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 Related Technology 4 described above.

[0286] Exemplarily, the first delay is determined based on 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 packet in the first PDU Set that has not yet been transmitted 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 functional network element is t', the start time when the source access network device sends the data packet of the first PDU Set to the target access network device is t", the PSDB of the first PDU Set is t, then the first delay is t-(t"-t').

[0287] Exemplarily, the first delay is determined based on 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 packet in the first PDU Set that has not yet been transmitted 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 functional network element is t', the start time when the source access network device sends the data packet 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', the PSDB of the first PDU Set is t, then the first delay is t-(t')-t'.

[0288] In one 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 the one or more data packets of the first PDU Set from the source access network device received by the target access network device meet the first delay, the target access network device sends the data packets of the one or more data packets of the first PDU Set from the source access network device that have not been transmitted to the terminal device. Alternatively, the target access network device needs to 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 delay.

[0289] In an embodiment of the present 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 repeated here.

[0290] Optionally, the first information further includes a remaining transmission delay budget within the first delay. For a description of the remaining delay budget within the first delay, reference may be made to the description of the remaining transmission delay budget within the first delay in S740, which will not be repeated here.

[0291] Optionally, the first information includes a 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 repeated here.

[0292] It should be noted that the following description of redundant data packets corresponds to processing scenario three in related technology 6. If it corresponds to processing scenario one or processing scenario two in related technology 6, the target access network device may determine not to send the untransmitted data packets in the one or more data packets of the first PDU Set from the source access network device to the terminal device based on packet loss occurring in the process of sending one or more data packets of the first PDU Set from the source access network device to the terminal device.

[0293] 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 yet been transmitted in the first PDU Set to the number of redundant data packets corresponding to the data packets that have not yet been transmitted in the first PDU Set, or the first redundant packet ratio is the ratio of redundant data packets in the data packets that have not yet been transmitted in the first PDU Set (that is, referring to the description of related technology 6, the data packets that have not yet been transmitted in the first PDU Set include redundant data packets), or the first redundant packet ratio is the tolerable upper limit of packet loss in the data packets that have not yet been transmitted in the first PDU Set.

[0294] In an embodiment of the present application, the number of redundant data packets corresponding to the data packets that have not yet been transmitted in the first PDU Set is the difference between the maximum number of redundant data packets in the first PDU Set and the number of lost data packets that have been lost among some data packets in the first PDU Set sent by the source access network device to the terminal device.

[0295] 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 number of data packets that have not been transmitted in the first PDU Set is 20. The number of data packets 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.

[0296] In an embodiment of the present application, the tolerable upper limit of packet loss in the data packets that have not yet been transmitted in the first PDU Set can be understood as the number of packet losses exceeding the upper limit of packet loss, and the target access network device does not send the data packets that have not yet been transmitted in one or more data packets of the first PDU Set from the source access network device to the terminal device.

[0297] In one possible implementation, the target access network device processes one or more data packets from the source access network device based on 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 based on the first information; further, first, the target access network device determines a first number of data packets lost in the process of sending one or more data packets of the first PDU Set from the source access network device to the terminal device; when the first number is greater than the number of redundant data packets corresponding to the first redundant packet ratio, the target access network device determines not to send the data packets that have not yet been transmitted in the one or more data packets of the first PDU Set from the source access network device. This solution can avoid the waste of transmission resources caused by still sending data packets of the first PDU Set to the terminal device when the first number of lost data packets makes the first PDU Set unable to be correctly decoded.

[0298] 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 data packets that have been lost among the data 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. Accordingly, the source access network device determines a second redundant packet ratio, which is the ratio of the first threshold value to the sum of the data packets in the first PDU Set that have not yet been transmitted and the data packets that have been lost and sent to the target access network device. In other words, it can be understood that the source access network device sends the data packets that have been lost to the target access network device, which is retransmitted by the target access network device. This is equivalent to the fact 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 remains at the first threshold value. For example, if the number of data packets in the first PDU Set that have not yet been transmitted is 20, the first threshold value is 10, and the number of data packets that have been lost among the partial data packets 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 sends to the target access network device the data packets that have been lost among the data 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, which can improve the success rate of transmission of the first PDU Set. Optionally, the first information includes a third redundant packet ratio. As a possible implementation method, the source access network device can send to the target terminal device the data packets that are being transmitted to the terminal device through the source access network device. Accordingly, 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 data packets that have not been transmitted in the first PDU Set to the sum of the data packets that have not been transmitted in the first PDU Set and the data packets that are being transmitted to the terminal device through the source access network device. Optionally, the source access network device can stop transmitting to the terminal device the data packets that are being transmitted to the terminal device through the source access network device.

[0299] Optionally, although not shown, the communication method provided in the embodiment of the present application further includes:

[0300] S831. The source access network device determines first information according to the transmission status of the data packet of the first PDU Set sent to the terminal device.

[0301] Exemplarily, the source access network device determines that packet loss has occurred based on the transmission status of the data packet of the first PDU Set sent to the terminal device, and accordingly determines that the first information includes the above-mentioned first redundant packet ratio. This is introduced in the description of the above-mentioned first redundant packet ratio in the embodiment of the present application and will not be repeated here.

[0302] Optionally, as shown in FIG8 , the communication method provided in the embodiment of the present application further includes:

[0303] 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.

[0304] In an embodiment of the present application, the first indication information is used to indicate that at least one first data packet in the first PDU Set that is being transmitted to the terminal device through the source access network device has been lost.

[0305] It should be noted that, in the process of the source access network device sending the data packets that have not yet been transmitted in the first PDU Set to the target access network device, one or more data packets among the data packets sent by the source access network device to the terminal device may also be in the transmission process. If packet loss occurs during this process, the source access network device can send a first indication information to the target access network device.

[0306] Optionally, the first indication information may 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 may include identification information of the first PDU Set, such as sequence number information of the first PDU Set. Optionally, the first indication information may be other control plane information, which is not limited in this embodiment of the present application.

[0307] In one possible implementation, corresponding to processing scenario one or processing scenario two in related technology 6, the first data packet in the first PDU Set that is being transmitted to the terminal device through the source access network device is lost, and the target access network device determines not to send the data packets that have not yet been transmitted in one or more data packets of the first PDU Set from the source access network device to the terminal device.

[0308] In another possible implementation, corresponding to the processing scenario three in related technology 6, the target access network device determines the updated first redundant packet ratio based on the first indication information, and determines whether to send one or more data packets of the first PDU Set from the source access network device to the terminal device based on the updated first redundant packet ratio. For example, the first redundant 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 redundant 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 of the one or more data packets of the first PDU Set from the source access network device to the terminal device. If the target access network device has already sent at least one data packet of the one or more data packets of the first PDU Set from the source access network device to the terminal device, the value of 20 is correspondingly reduced.

[0309] The above two possible implementation methods can enable the source access network device to promptly 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, thereby avoiding the waste of transmission resources caused by the target access network device still sending the data packet of 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.

[0310] Optionally, the first indication information is further used to indicate the number of at least one first data packet that has been lost. For example, the first indication information is sent once every n packet losses. This solution allows the target access network device to determine the number of at least one first data packet that has been lost.

[0311] Optionally, as shown in FIG8 , the communication method provided in the embodiment of the present application further includes:

[0312] 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 the at least one first data packet from the source access network device.

[0313] In an embodiment of the present application, the source access network device can send at least one first data packet to the target access network device, which then sends it to the terminal device. This can avoid the target access network device not sending 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 in the first PDU Set being transmitted to the terminal device through the source access network device, thereby increasing the transmission success rate of the data packets in the first PDU Set that have not yet been transmitted from the target access network device to the terminal device.

[0314] In the communication method provided by an embodiment of the present application, a source access network device receives a first PDU Set from a user plane functional network element and sends a portion of data packets of the first PDU Set to a terminal device. When the terminal device switches to a target access network device, the source access network device sends data packets in the first PDU Set that have not yet been transmitted to the target access network device, wherein at least one of the data packets in the first PDU Set that have not yet been transmitted carries first information. 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 based on the first information. This solution ensures the joint transmission of the first PDU Set by the source access network device and the target access network device in the switching scenario.

[0315] The above description primarily describes the solutions provided by the embodiments of the present application from the perspective of interaction between 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. Alternatively, the above description primarily describes the solutions provided by the embodiments of the present application from the perspective of interaction between a user plane function network element, a source access network device, a target access network device, and a terminal device. Accordingly, the embodiments of the present application also provide a communication device for implementing the various methods described above. The communication device can be any device or network element in the above method embodiments, or a device that includes any of the above devices or network elements, or a component that can be used in any of the above devices or network elements. It will be understood that, to implement the above functions, the communication device includes hardware structures and / or software modules corresponding to each function. Those skilled in the art will readily appreciate that, in conjunction with the various exemplary units and algorithm steps described in the embodiments disclosed herein, the present application can be implemented in hardware or a combination of hardware and computer software. Whether a function is implemented in hardware or by computer software driving hardware depends on the specific application and design constraints of the technical solution. Professionals and technicians may use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of the present application.

[0316] For example, FIG9 is a schematic diagram of a communication device provided in an embodiment of the present application, wherein the communication device includes a transceiver module 910 and a processing module 920. The transceiver module 910, which may also be referred to as a transceiver unit, is used to implement transceiver functions, and may be, for example, a transceiver circuit, a transceiver, a transceiver, or a communication interface.

[0317] Taking the communication device as the access network device in the above method embodiment (which may be a chip of the access network device, or a module of the access network device, or an internal device of the access network device) as an example:

[0318] The transceiver module 910 is used 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 the first PDU Set.

[0319] The transceiver module 910 is further configured to receive one or more data packets of the first PDU Set from the user plane functional network element.

[0320] The processing module 920 is configured to add first information to at least one data packet of one or more data packets of a first PDU Set from a user plane functional network element.

[0321] 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, and the first information is used by 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.

[0322] In a possible implementation, the processing module 920 is further configured to determine the first information according to a transmission status of a data packet of the first PDU Set sent to the first terminal device.

[0323] In one 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 first information is used by 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, 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, 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.

[0324] In a possible implementation, the first information includes a first delay, where the first delay is a transmission delay budget of the first PDU Set from the first terminal device to the second terminal device.

[0325] In one possible implementation, the first delay is determined based on the time when the transceiver module 910 sends the first data packet of the first PDU Set to the first terminal device and the delay budget PSDB of the first PDU Set. The PSDB of the first PDU Set is used to characterize the transmission delay budget of the first PDU Set.

[0326] In an embodiment of the present application, the transceiver module 910 is further used to send 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 first PDU Set data packet to the first terminal device.

[0327] 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 an internal device of the first terminal device) as an example:

[0328] The transceiver module 910 is configured to receive one or more data packets from an access network device, wherein 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.

[0329] The processing module 920 is configured to process the data packet of the first PDU Set according to the first information.

[0330] In a possible implementation, the first information is determined by the access network device according to a transmission status of a data packet of the first PDU Set sent to the transceiver module 910 .

[0331] In one 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 based on the first information, including 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, to determine that one or more data packets received by the transceiver module 910 from the access network device belong to the first PDU Set.

[0332] In one possible implementation, the first information includes a first delay, where the first delay is a transmission delay budget for the first PDU Set from the first terminal device to the second terminal device. The processing module 920 is configured to process data packets of the first PDU Set based on the first information, including: if the processing module 920 determines that one or more data packets received from the access network device meet the first delay, the transceiver module 910 sending the data packets of the first PDU Set to the second terminal device.

[0333] In one possible implementation, the first delay is determined based on the time when the access network device sends the first data packet of the first PDU Set to the first terminal device and the delay budget PSDB of the first PDU Set. The PSDB of the first PDU Set is used to characterize the transmission delay budget of the first PDU Set.

[0334] In an embodiment of the present application, the transceiver module 910 is further used to receive second indication information from the access network device, where the second indication information is used to indicate that packet loss occurs during the process of the access network device sending the first PDU Set data packet to the first terminal device.

[0335] The processing module 920 is further used to determine not to send the data packet of the first PDU Set to the second terminal device according to the second indication information.

[0336] In an embodiment of the present application, the processing module 920 is further used to determine not to send the data packets of the first PDU Set to the second terminal device based on the second indication information, including: the processing module 920 is also used to determine the current accumulated first packet loss number based on the number of received second indication information, the first packet loss number including the number of packet losses that occurred in 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 occurred in the process of the transceiver module 910 sending the data packets of the first PDU Set to the second terminal device. When 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.

[0337] Taking the communication device as the source access network device in the above method embodiment (which may be a chip of the source access network device, or a module of the source access network device, or an internal device of the source access network device) as an example:

[0338] The transceiver module 910 is configured to receive a first PDU Set and send a partial data packet of the first PDU Set to a terminal device.

[0339] The processing module 920 is configured to add first information to at least one data packet among the data packets that have not yet 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.

[0340] The transceiver module 910 is further configured to send untransmitted data packets in the first PDU Set to the target access network device when the terminal device switches to the target access network device. At least one of the untransmitted data packets in the first PDU Set carries first information, and the first information is used to process the one or more data packets from the transceiver module 910 according to the first information when the target access network device sends the one or more data packets from the transceiver module 910 to the terminal device.

[0341] In a possible implementation, the processing module 920 is further configured to determine the first information according to a transmission status of a data packet of the first PDU Set sent to the terminal device.

[0342] In one 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 first information is used when the target access network device sends one or more data packets from the source access network device to the terminal device, and processes the one or more data packets from the source access network device according to the first information, including: 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, for the target access network device to determine that the one or more data packets received from the transceiver module 910 belong to the first PDU Set.

[0343] In a possible implementation, the first information includes a first delay, where the first delay is used to indicate a transmission delay budget for data packets that have not yet been transmitted in the first PDU Set.

[0344] In a possible implementation, the first delay is determined according to a 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.

[0345] In one possible implementation, the first delay is determined based on the PSDB of the first PDU Set, including: the first delay information is determined based on 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 packet that has not yet 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.

[0346] In one possible implementation, the first information includes a first redundant packet ratio. The first redundant packet ratio is a ratio of the number of data packets included in the data packets that have not yet been transmitted in the first PDU Set to the number of redundant packets corresponding to the data packets that have not yet been transmitted in the first PDU Set, or the first redundant packet ratio is an upper limit of tolerable packet loss in the data packets that have not yet been transmitted in the first PDU Set.

[0347] In an embodiment 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 some data packets of the first PDU Set sent to the terminal device meets 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.

[0348] In a possible implementation, the first condition is that no packet loss occurs.

[0349] 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.

[0350] In one possible implementation, the transceiver module 910 is further used to send a first indication message to the target access network device, where the first indication message is used to indicate that at least one first data packet in the first PDU Set being transmitted to the terminal device through the transceiver module 910 has been lost.

[0351] In a possible implementation, the first indication information is further used to indicate the number of at least one first data packet that is lost.

[0352] 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.

[0353] 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 an internal device of the target access network device) as an example:

[0354] Transceiver module 910 is configured to receive one or more data packets from a source access network device when the terminal device switches to a target access network device. The one or more data packets are data packets in the first PDU Set that have not yet been transmitted. At least one of the one or more data packets carries the first information; the data packets in the first PDU Set that have not yet 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.

[0355] The processing module 920 is configured to process one or more data packets from the source access network device according to the first information.

[0356] In an embodiment of the present application, the first information is determined by the source access network device based on the transmission status of the data packet of the first PDU Set sent to the terminal device.

[0357] In one 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 processes one or more data packets from the source access network device based on the first information, including: the processing module 920 is configured to determine that the one or more data packets received by the transceiver module 910 from the source access network device belong to the first PDU Set based on 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.

[0358] In one possible implementation, the first information includes a first delay, where the first delay is used to indicate a transmission delay budget for data packets in the first PDU Set that have not yet been transmitted. The processing module 920 is configured to process one or more data packets from the source access network device based on the first information, including: when the one or more data packets received from the source access network device meet the first delay, the transceiver module 910 is configured to send the one or more data packets received from the first PDU Set of the source access network device to the terminal device.

[0359] In a possible implementation, the first delay is determined according to a 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.

[0360] In one possible implementation, the first delay is determined based on the PSDB of the first PDU Set, including: the first delay information is determined based on 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 packet that has not yet been 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.

[0361] In one 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 yet been transmitted in the first PDU Set to the number of redundant packets corresponding to the data packets that have not yet 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 yet 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 the first number of data packets that are lost in the process of sending one or more data packets from the source access network device to the terminal device. In the case that the first number is greater than the number of redundant packets corresponding to the first redundant packet ratio, the processing module 920 is also used to determine not to send the data packets that have not yet been transmitted in the one or more data packets from the source access network device.

[0362] In a possible implementation, the packet loss situation of some data packets of the first PDU Set sent by the source access network device to the terminal device is that no packet loss occurs.

[0363] In a possible implementation, the packet loss situation of some data packets of 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.

[0364] In the embodiment of the present application, the transceiver module 910 is further configured to receive lost data packets from the data packets that have been transmitted in the first PDU Set from the source access network device.

[0365] In an embodiment of the present application, the transceiver module 910 is also used to receive 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 in the first PDU Set being transmitted to the terminal device through the source access network device has been lost.

[0366] In the embodiment of the present application, the transceiver module 910 is further configured to receive at least one first data packet from a source access network device.

[0367] All relevant contents of each step involved in the above method embodiment can be referred to the functional description of the corresponding functional module and will not be repeated here. Optionally, the communication device may further include a storage module 930, which 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.

[0368] In the embodiment of the present application, the first communication node is presented in the form of various functional modules divided in an integrated manner. The "module" here can refer to a specific ASIC, circuit, processor and memory that executes one or more software or firmware programs, integrated logic circuit, and / or other devices that can provide the above functions. In a simple embodiment, those skilled in the art can imagine that the communication device can take the form of the communication device 600 shown in Figure 6.

[0369] For example, the processor 601 in the communication device 600 shown in FIG6 can call the computer execution instructions stored in the memory 603 so that the communication device 600 executes the perception method in the above method embodiment.

[0370] Specifically, the functions / implementation processes of the transceiver module 910 and the processing module 920 in FIG9 can be implemented by the processor 601 in the communication device 600 shown in FIG6 calling computer-executable instructions stored in the memory 603. Alternatively, the functions / implementation processes of the processing module 920 in FIG9 can be implemented by the processor 601 in the communication device 600 shown in FIG6 calling computer-executable instructions stored in the memory 603, and the functions / implementation processes of the transceiver module 910 in FIG9 can be implemented by the communication interface 604 in the communication device 600 shown in FIG6.

[0371] It should be understood that one or more of the above modules or units can be implemented by software, hardware, or a combination of the two. When any of the above modules or units is implemented in software, the software exists in the form of computer program instructions and is stored in a memory, and a processor can be used to execute the program instructions and implement the above method flow. The processor can be built into an SoC (system on chip) or an ASIC, or it can be an independent semiconductor chip. In addition to the core used to execute software instructions to perform calculations or processing within the processor, it can further include necessary hardware accelerators, such as field programmable gate arrays (FPGAs), PLDs (programmable logic devices), or logic circuits that implement dedicated logic operations.

[0372] 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, a 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 not rely on the software to execute the above method flow.

[0373] Optionally, an embodiment of the present application further provides a communication device (for example, the communication device may be a chip or a chip system), which includes a processor for implementing the method in any of the above method embodiments. In one possible design, the communication device also 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 may be composed of a chip, or it may include a chip and other discrete devices, which is not specifically limited in the embodiment of the present application.

[0374] Optionally, an embodiment of the present application also provides a computer-readable storage medium, which stores a computer program or instruction. When the computer program or instruction is 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 methods.

[0375] Optionally, an embodiment of the present application further provides a communication system, which includes the communication device described in the above method embodiment.

[0376] In the above embodiments, all or part of the embodiments can be implemented by software, hardware, firmware, or any combination thereof. When implemented using a software program, all or part of the embodiments can be implemented in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions according to the embodiments of the present application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. 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 one website, computer, server, or data center to another website, computer, server, or data center via a wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) method. 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 data center that includes one or more media integrated therein. The available medium may be a magnetic medium (eg, a floppy disk, a hard disk, a magnetic tape), an optical medium (eg, a DVD), or a semiconductor medium (eg, a solid state disk (SSD)).

[0377] Although the present application is described herein in conjunction with various embodiments, in the process of implementing the claimed application, those skilled in the art may understand and implement other variations of the disclosed embodiments by reviewing the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other components or steps, and "a" or "an" does not exclude multiple situations. A single processor or other unit may implement several functions listed in the claims. Certain measures are recorded in different dependent claims, but this does not mean that these measures cannot be combined to produce good results.

[0378] Although the present application has been described with reference to specific features and embodiments thereof, it is apparent that various modifications and combinations may be made thereto without departing from the scope of the present application. Accordingly, this specification and the drawings are merely illustrative of the present application as defined by the appended claims and are deemed to cover any and all modifications, variations, combinations or equivalents within the scope of the present application. Obviously, those skilled in the art may make various modifications and variations to the present application without departing from the scope of the present application. Thus, the present application is intended to include such modifications and variations as fall within the scope of the claims of the present application and their equivalents.

Claims

1. A communication method, characterized in that: include: 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 in 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 processing the data packets of the first PDU Set according to the first information when the first terminal device sends the first PDU Set to the second terminal device.

2. The method according to claim 1, characterized in that The method also includes: the access network device determines the first information according to the transmission status of the data packet 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: 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; wherein, the first information is used for processing the data packets of the first PDU Set according to the first information when the first terminal device sends the first PDU Set to the second terminal device, including: 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 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 delay, which is a transmission 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 delay is determined based on the time when the access network device sends the first data packet of the first PDU Set to the first terminal device and 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.

6. The method according to any one of claims 1 to 5, characterized in that The method further comprises: The access network device sends 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 packet of the first PDU Set to the first terminal device.

7. A communication method, characterized in that: include: The first terminal device receives one or more data packets from the access network device, where 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.

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

9. The method according to claim 7, characterized in that: 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 packet 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 based on 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, characterized in that The first information includes a first delay, where the first delay is a transmission delay budget of the first PDU Set from the first terminal device to the second terminal device; The first terminal device processes the data packet 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 delay, the first terminal device sends the data packet of the first PDU Set to the second terminal device.

11. The method according to claim 10, characterized in that The first delay is determined based on the time when the access network device sends the first data packet of the first PDU Set to the first terminal device and 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.

12. The method according to any one of claims 7 to 11, characterized in that The method further comprises: The first terminal device receives second indication information from the access network device, where the second indication information is used to indicate that packet loss occurs during the process in which the access network device sends 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 based on the second indication information.

13. The method according to claim 12, characterized in that The first terminal device determines, according to the second indication information, not to send a data packet of the first PDU Set to the second terminal device, including: The first terminal device determines a currently accumulated first number of packet losses according to the number of received second indication information, where the first number of packet losses includes the number of packet losses that occur when the access network device sends the first PDU Set data packet to the first terminal device, and / or the number of packet losses that occur when the first terminal device sends the first PDU Set data packet to the second terminal device; When the first packet loss number is greater than a first threshold, the first terminal device determines not to send the data packet of the first PDU Set to the second terminal device.

14. A communication device, characterized in that: include: A transceiver module, configured to receive first indication information from a session management function network element, wherein the first indication information is used to instruct the access network device to add first information in a first protocol data unit set PDU Set; The transceiver module is further used to receive one or more data packets of the first PDU Set from the user plane function network element; The transceiver module is also used to send 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 to process the data packets of the first PDU Set according to the first information when the first terminal device sends the first PDU Set to the second terminal device.

15. The device according to claim 14, characterized in that The communication device also includes a processing module, which is used to determine the first information according to the transmission status of the data packet 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: 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; wherein, the first information is used for processing the data packets of the first PDU Set according to the first information when the first terminal device sends the first PDU Set to the second terminal device, including: 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 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 delay, which is a transmission delay budget of the first PDU Set from the first terminal device to the second terminal device.

18. The device according to claim 17, characterized in that The first delay is determined based on the time when the access network device sends the first data packet of the first PDU Set to the first terminal device and 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.

19. The device according to any one of claims 14 to 18, characterized in that The method transceiver module is also used for: Send second indication information to the first terminal device, where the second indication information is used to indicate that packet loss occurs in the process of the access network device sending the data packet of the first PDU Set to the first terminal device.

20. A communication device, characterized in that: include: A transceiver module, configured to receive one or more data packets from an access network device, wherein 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 is used to process the data packet of the first PDU Set according to the first information.

21. The device according to claim 20, characterized in that The first information is determined by the access network device according to the transmission status of the data packet of the first PDU Set sent to the first terminal device.

22. The device according to claim 20, characterized in that 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 used to process the data packets of the first PDU Set according to the first information, including: the processing module is used to determine that one or more data packets received from the access network device belong to the first PDU Set based on 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 device according to any one of claims 20 to 22, characterized in that The first information includes a first delay, where the first delay is a transmission delay budget of the first PDU Set from the first terminal device to the second terminal device; The processing module is used to process the data packet 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 delay, the transceiver module sends the data packet of the first PDU Set to the second terminal device.

24. The device according to claim 23, characterized in that The first delay is determined based on the time when the access network device sends the first data packet of the first PDU Set to the first terminal device and 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.

25. The device according to any one of claims 20 to 24, characterized in that The transceiver module is further used to receive second indication information from the access network device, where the second indication information is used to indicate that packet loss occurs during the process in which the access network device sends the data packet of the first PDU Set to the first terminal device; The processing module is also used to determine not to send the data packet of the first PDU Set to the second terminal device based on the second indication information.

26. The device according to claim 25, characterized in that The processing module is also used to determine, according to the second indication information, not to send the data packet of the first PDU Set to the second terminal device, including: The processing module is further used to determine the currently accumulated first packet loss number according to the number of the second indication information received, where the first packet loss number includes the number of packet losses that occur in the process of the access network device sending the first PDU Set data packet to the first terminal device, and / or the number of packet losses that occur in the process of the first terminal device sending the first PDU Set data packet to the second terminal device; When the first packet loss number is greater than a first threshold, the processing module determines not to send the data packet of the first PDU Set to the second terminal device.

27. A communication device, characterized in that: The communication device comprises a module for executing the method according to any one of claims 1 to 6, or comprises a module for executing the method according to any one of claims 7 to 13.

28. A communication device, characterized in that: The communication device comprises a processor; the processor is configured to execute the method according to any one of claims 1 to 6, or to cause the communication device to execute the method according to any one of claims 7 to 13.

29. A computer-readable storage medium, characterized in that: The computer-readable storage medium comprises instructions, which, when executed, enable the method according to any one of claims 1 to 6 to be implemented, or enable the method according to any one of claims 7 to 13 to be implemented.

30. A computer program product, characterized in that The computer program product comprises instructions, which, when executed, enable the method according to any one of claims 1 to 6 to be implemented, or enable the method according to any one of claims 7 to 13 to be implemented.

31. A communication system, characterized in that: The communication system comprises the communication device according to any one of claims 14 to 19 and the communication device according to any one of claims 20 to 26.

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