Communication method and communication apparatus

Abstract

The present application relates to a communication method and a communication apparatus. The method comprises: an application function network element providing information for synchronous transmission of multi-modal traffic flows, and a user plane function network element identifying an associated PDU set between the multi-modal traffic flows on the basis of the information, and adding association information to a GTP-U of the associated PDU set, such that an access network device can determine the associated PDU set, and then perform synchronous transmission of the associated PDU set, or the access network device identifies the associated PDU set between the multi-modal traffic flows on the basis of the information provided by the application function network element, so as to perform synchronous transmission of the associated PDU set. Thus, synchronous transmission guarantee for multi-modal traffic flows can be achieved.

Description

Communication method and communication device

[0001] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office of China on November 29, 2023, with application number 202311634986.3 and invention name “A 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 in particular, to a communication method and a communication device. Background Art

[0003] Multimodal services generally refer to services that include multiple modal service flows. For example, a multimodal service flow can include service flows in different modalities, such as audio, video, tactile, temperature, and / or brightness. For example, a common multimedia service may include audio, video, and / or control data. To provide a good and consistent service experience, synchronized transmission between the multiple service flows of a multimodal service is required.

[0004] Therefore, how to ensure synchronous transmission between multiple service flows of multimodal services has become an urgent problem that needs to be solved.

[0005] Summary of the Invention

[0006] The present application provides a communication method and a communication device to achieve synchronous transmission guarantee of multiple service flows of multimodal services.

[0007] In the first aspect, a communication method is provided, which can be executed by an access network device. Unless otherwise specified, "access network device" can refer to the access network device itself, or it can refer to a device that can support the access network device to implement its functions. For the sake of convenience, the access network device will be used for description below.

[0008] The method includes: an access network device obtains first indication information, where the first indication information is used to indicate that a first service flow and a second service flow are associated; the access network device receives a first protocol data unit set (PDU Set) of the first service flow and a second PDU Set of the second service flow, where the first PDU Set and / or the second PDU Set carry association information, and the association information is used by the access network device to determine that the first PDU Set and the second PDU Set are associated; the access network device synchronously transmits the first PDU Set and the second PDU Set based on the first indication information and the association information.

[0009] Based on the above method, the access network device can determine that the first PDU Set of the first service flow and the second PDU Set of the second service flow are associated according to the first indication information and the association information carried by the first PDU Set and / or the second PDU Set, and then synchronously transmit the associated PDU Set, thereby achieving synchronous transmission guarantee of multiple service flows.

[0010] In combination with the first aspect, in some implementations, the method also includes: the access network device obtains second indication information, and the second indication information is used to indicate the synchronization requirement between the first service flow and the second service flow; the access network device synchronously transmits the first PDU Set and the second PDU Set according to the first indication information and the associated information, including: the access network device synchronously transmits the first PDU Set and the second PDU Set according to the first indication information, the associated information and the second indication information.

[0011] Optionally, the synchronization requirement comes from the core network side, such as an application function network element, a session management function network element, or a policy control function network element.

[0012] Based on the above implementation method, the access network device can transmit the PDU Set associated with the first business flow and the second business flow according to the synchronization requirements between the first business flow and the second business flow, which helps to achieve synchronous transmission guarantee of multiple business flows.

[0013] In combination with the first aspect or any implementation thereof, in other implementations, the synchronization requirement includes a maximum transmission delay difference between PDU Sets associated with the first service flow and the second service flow. Alternatively, the synchronization requirement includes an overall transmission delay requirement between the PDU Sets associated with the first service flow and the second service flow, such as a delay budget requirement from receiving the first data packet of any associated PDU Set to sending all associated PDU Sets.

[0014] Based on the above implementation method, the access network device can transmit the PDU Set associated in the first business flow and the second business flow according to the maximum value of the transmission delay difference between the PDU Sets associated between the first business flow and the second business flow or the overall transmission delay requirement between the PDU Sets associated between the first business flow and the second business flow, which helps to achieve synchronous transmission guarantee of multiple business flows.

[0015] In combination with the first aspect or any implementation manner thereof, in some other implementation manners, the access network device synchronously transmits the first PDU Set and the second PDU Set according to the first indication information and the association information, including: the access network device determines that the first service flow and the second service flow are associated according to the first indication information; the access network device determines that the first PDU Set and the second PDU Set are associated according to the association information; and the access network device synchronously transmits the associated first PDU Set and second PDU Set.

[0016] In combination with the first aspect or any implementation manner thereof, in some other implementation manners, the first PDU Set and / or the second PDU Set carries association information, including: the first PDU Set carries first association information, and the second PDU Set carries second association information; the access network device determines that the first PDU Set and the second PDU Set are associated based on the association information, including: when the first association information and the second association information are the same, the difference between the first association information and the second association information is within a threshold range, or the difference between the first association information and the second association information is less than or equal to a threshold, the access network device determines that the first PDU Set and the second PDU Set are associated.

[0017] Based on the above implementation, the access network device can determine the PDU Sets associated with multiple service flows, and then synchronously transmit the associated PDU Sets, thereby ensuring the synchronous transmission of multiple service flows.

[0018] In combination with the first aspect or any implementation thereof, in some other implementations, the threshold value comes from the core network side, such as an application function network element, a session management function network element, a policy control function network element or a user plane function network element.

[0019] In combination with the first aspect or any implementation manner thereof, in some other implementation manners, the association information is used to indicate the offset value between the identification information of the associated PDU Set between the first business flow and the second business flow; the first PDU Set also carries first identification information, and the second PDU Set also carries second identification information; the access network device determines that the first PDU Set and the second PDU Set are associated based on the association information, including: when the difference between the first identification information and the second identification information is equal to the offset value, the access network device determines that the first PDU Set and the second PDU Set are associated.

[0020] Based on the above implementation, the access network device can receive the offset value between the identification information of the PDU Set associated between the first service flow and the second service flow through the user plane. Compared with pre-configuring the offset value through the control plane, the obtained offset value can be more consistent with the current service flow, which helps to ensure the synchronous transmission of multiple service flows. That is, this association information is sent to the access network device through the user plane.

[0021] In combination with the first aspect or any implementation manner thereof, in some other implementation manners, the first PDU Set carries the association information, the second PDU Set does not carry the association information, and the association information includes the identifier of the second service flow and the offset value, that is, the access network device can find the second PDU Set associated with the PDU Set in the second service flow based on the identifier of the second service flow carried by the first PDU Set and the offset value; or, the first PDU Set does not carry the association information, the second PDU Set carries the association information, and the association information includes the identifier of the first service flow and the offset value, that is, the access network device can find the first PDU Set associated with the PDU Set in the first service flow based on the identifier of the first service flow carried by the second PDU Set and the offset value; or, the first PDU Set and / or the second PDU Set carry association information, including: the first PDU Set carries the first association information, the second PDU Set carries the second association information, the first association information includes the identifier of the reference service flow and the first offset value, and the first offset value is the associated PDU between the first service flow and the reference service flow. The offset value between the identification information of the reference service flow and the reference service flow is selected from the group consisting of the first PDU Set and the second PDU Set, the second association information includes the identifier of the reference service flow and the second offset value, and the second offset value is the offset value between the identification information of the associated PDU Set between the second service flow and the reference service flow; or, the first PDU Set and / or the second PDU Set carry association information, including: the first PDU Set carries first association information, the second PDU Set carries second association information, the first association information includes the identifier of the second service flow and the offset value, and the second association information includes the identifier of the first service flow and the offset value; or, the first PDU Set and / or the second PDU Set carry association information, including: the first PDU Set carries first association information, the second PDU Set carries second association information, the first association information includes first identification information, and the second association information includes the first identification information, so that the access network device determines that the first PDU Set is associated with the second PDU Set based on the same first identification information carried in the associated first service flow and the second service flow, and synchronously transmits the associated first PDU Set and second PDU Set.

[0022] In combination with the first aspect or any implementation manner thereof, in some other implementation manners, the first identification information is the first PDU Set sequence number (SN), and the second identification information is the second PDU Set SN; or, the first identification information is the first timestamp, and the second identification information is the second timestamp; or the first identification information is the first PDU Set synchronization sequence identifier, and the second identification information is the second PDU Set synchronization sequence identifier, wherein the first PDU Set synchronization sequence identifier and the second PDU Set synchronization sequence identifier are used to identify the sequence information corresponding to the first PDU Set and the second PDU Set and are the same. Exemplarily, the first PDU Set sequence identifier and the second PDU Set sequence identifier can be the first PDU Set sequence number and the second PDU Set sequence number.

[0023] In combination with the first aspect or any implementation manner thereof, in some other implementation manners, the method further includes: the access network device receives an offset value between the association information of the associated PDU Set between the first service flow and the second service flow from the user plane function network element or the application function network element through control plane signaling; the first PDU Set and / or the second PDU Set carries association information, including: the first PDU Set carries first association information, and the second PDU Set carries second association information; the access network device determines that the first PDU Set and the second PDU Set are associated based on the association information, including: when the difference between the first association information and the second association information is equal to the offset value, the access network device determines that the first PDU Set and the second PDU Set are associated.

[0024] Based on the above implementation method, the access network device can receive the offset value between the identification information of the associated PDU Set between the first service flow and the second service flow through the control plane. Compared with obtaining the offset value through the user plane, it can reduce the implementation complexity and directly identify the associated first PDU Set and second PDU Set based on the pre-configured offset value.

[0025] In combination with the first aspect or any implementation thereof, in some other implementations, the first association information is a first PDU Set SN, and the second association information is a second PDU Set SN; or, the first association information is a first timestamp, and the second association information is a second timestamp.

[0026] In combination with the first aspect or any implementation manner thereof, in some other implementation manners, the association information is included in a general packet radio service tunneling protocol-user plane (GTP-U) header of the PDU Set.

[0027] Exemplarily, the association information is included in the GTP-U layer of the data packet corresponding to the PDU Set.

[0028] In combination with the first aspect or any implementation manner thereof, in some other implementation manners, the first indication information includes an identifier of the first business flow and an identifier of the second business flow; or, the first indication information includes an identifier of the first business flow, an identifier of the first session to which the first business flow belongs, an identifier of the first terminal device to which the first session belongs, an identifier of the second business flow, an identifier of the second session to which the second business flow belongs, and / or an identifier of the second terminal device to which the second session belongs.

[0029] On the second aspect, a communication method is provided, which can be executed by a user plane function network element. Unless otherwise specified, "user plane function network element" can refer to the user plane function network element itself, or it can refer to a device that can support the user plane function network element to realize its function. For the sake of convenience of description, the user plane function network element will be used for description below.

[0030] The method includes: a user plane function network element obtains first indication information, where the first indication information is used to indicate that a first service flow and a second service flow are associated; the user plane function network element receives a first PDU Set of the first service flow and a second PDU Set of the second service flow, where the first PDU Set carries third association information and the second PDU Set carries fourth association information, and the third association information and the fourth association information are used by the user plane function network element to determine that the first PDU Set is associated with the second PDU Set; the user plane function network element adds association information to the first PDU Set and / or the second PDU Set based on the first indication information, the third association information and the fourth association information, and the association information is used by the access network device to determine that the first PDU Set is associated with the second PDU Set; and the user plane function network element sends the first PDU Set and the second PDU Set to the access network device.

[0031] Based on the above method, the user plane functional network element can determine that the first PDU Set of the first service flow and the second PDU Set of the second service flow are associated based on the first indication information, and the third association information carried by the first PDU Set and the fourth association information carried by the second PDU Set, and add association information that can be obtained by the access network device to the first PDU Set and / or the second PDU Set, so that the access network device can determine that the first PDU Set of the first service flow and the second PDU Set of the second service flow are associated based on the association information carried by the first PDU Set and / or the second PDU Set, and then synchronously transmit the associated PDU Sets, thereby achieving synchronous transmission guarantee of multiple service flows.

[0032] In combination with the second aspect, in some implementations, the user plane functional network element adds association information to the first PDU Set and / or the second PDU Set based on the first indication information, the third association information and the fourth association information, including: the user plane functional network element determines that the first service flow and the second service flow are associated based on the first indication information; the user plane functional network element determines that the first PDU Set and the second PDU Set are associated based on the third association information carried in the first PDU Set and the fourth association information carried in the second PDU Set; the user plane functional network element adds the association information to the first PDU Set and / or the second PDU Set.

[0033] In combination with the second aspect or any implementation manner thereof, in some other implementation manners, the user plane functional network element determines that the first PDU Set and the second PDU Set are associated based on the third association information and the fourth association information, including: when the third association information and the fourth association information are the same, the difference between the third association information and the fourth association information is less than or equal to a threshold, the difference between the third association information and the fourth association information is within a threshold range, or the difference between the third association information and the fourth association information is equal to an offset value, the user plane functional network element determines that the first PDU Set and the second PDU Set are associated, and the offset value is the offset value between the association information of the associated PDU Sets between the first service flow and the second service flow.

[0034] Based on the above implementation, the user plane functional network element can determine the PDU Sets associated with multiple service flows, and then add associated information that can be obtained by the access network device to the associated PDU Sets, which helps to achieve synchronous transmission guarantee of multiple service flows.

[0035] In combination with the second aspect or any implementation manner thereof, in some other implementation manners, the threshold value and / or the offset value comes from a session management function network element, or a policy control function network element, or an application function network element.

[0036] In combination with the second aspect or any implementation manner thereof, in some other implementation manners, the user plane functional network element adds association information to the first PDU Set and / or the second PDU Set based on the first indication information, the third association information and the fourth association information, including: the user plane functional network element adds first association information to the first PDU Set and adds second association information to the second PDU Set based on the first indication information, the third association information and the fourth association information, and the first association information and the second association information are the same.

[0037] Based on the above implementation, the user plane functional network element can add the same association information to the associated PDU Sets, so that the access network equipment can synchronously transmit the PDU Sets carrying the same association information in the associated service flows.

[0038] In combination with the second aspect or any implementation thereof, in some other implementations, the first association information is a first PDU Set synchronization sequence identifier, and the second association information is a second PDU Set synchronization sequence identifier. That is, the user plane functional network element adds the same PDU Set sequence identifier to the associated PDU Sets.

[0039] In combination with the second aspect or any implementation thereof, in other implementations, the first association information is a first PDU Set SN, and the second association information is a second PDU Set SN. That is, the user plane functional network element adds the same PDU Set SN to the associated PDU Sets.

[0040] In combination with the second aspect or any implementation thereof, in some other implementations, the association information is used to indicate the offset value between the identification information of the associated PDU Set between the first service flow and the second service flow; the method also includes: the user plane functional network element adds first identification information to the first PDU Set and adds second identification information to the second PDU Set, the first identification information is the same as the third association information, and the second identification information is the same as the fourth association information.

[0041] Based on the above implementation method, the user plane functional network element can provide the offset value between the identification information of the associated PDU Set between the first service flow and the second service flow to the access network device through the user plane. Compared with pre-configuring the offset value through the control plane, the obtained offset value can be more in line with the current service flow, which helps to achieve synchronous transmission guarantee of multiple service flows.

[0042] In combination with the second aspect or any implementation manner thereof, in some other implementation manners, the adding of association information to the first PDU Set and / or the second PDU Set includes: adding the association information to the first PDU Set, and not adding the association information to the second PDU Set, the association information including the identifier of the second business flow and the offset value; or, not adding the association information to the first PDU Set, and adding the association information to the second PDU Set, the association information including the identifier of the first business flow and the offset value; or, adding first association information to the first PDU Set, and adding second association information to the second PDU Set, the first association information including the identifier of the reference business flow and the first offset value, the first offset value being the offset value between the identification information of the associated PDU Set between the first business flow and the reference business flow, the second association information including the identifier of the reference business flow and the second offset value, the second offset value being the offset value between the identification information of the associated PDU Set between the second business flow and the reference business flow; or, adding first association information to the first PDU Set, and adding second association information to the second PDU Set, the first association information including the identifier of the reference business flow and the second offset value, the second offset value being the offset value between the identification information of the associated PDU Set between the second business flow and the reference business flow; Set adds second association information, the first association information includes the identifier of the second business flow and the offset value, and the second association information includes the identifier of the first business flow and the offset value; or, adds first association information to the first PDU Set, and adds second association information to the second PDU Set, the first association information includes first identification information, and the second association information includes the first identification information, so that the access network device determines that the first PDU Set is associated with the second PDU Set based on the same first identification information carried in the associated first business flow and the second business flow, and synchronously transmits the associated first PDU Set and second PDU Set.

[0043] In combination with the second aspect or any implementation thereof, in some other implementations, the third association information and the first identification information are a first PDU Set synchronization sequence identifier, such as a PDU Set SN, and the fourth association information and the second identification information are a second PDU Set synchronization sequence identifier, such as a PDU Set SN; or, the third association information and the first identification information are a first timestamp, and the fourth association information and the second identification information are a second timestamp.

[0044] In combination with the second aspect or any implementation manner thereof, in some other implementation manners, the method further includes: the user plane function network element determining the offset value based on the third association information and the fourth association information.

[0045] Based on the above implementation method, the user plane functional network element can determine the offset value between the identification information of the associated PDU Set between the first service flow and the second service flow. Compared with pre-configuring the offset value through the control plane, the offset value obtained by this method can be more real-time and accurate, more in line with the current service flow, and help to achieve synchronous transmission guarantee of multiple service flows.

[0046] In combination with the second aspect or any implementation thereof, in some other implementations, the method further includes: the user plane function network element obtains third indication information, and the third indication information is used to instruct the user plane function network element to identify the associated PDU Set.

[0047] In combination with the second aspect or any implementation thereof, in some other implementations, the third indication information is also used to indicate a method in which the user plane function network element identifies the associated PDU Set, and the method is any one of the following methods: timestamp-based identification or PDU Set SN-based identification.

[0048] In combination with the second aspect or any implementation manner thereof, in some other implementation manners, the timestamp-based identification includes at least one of the following methods: associating PDU Sets with the same timestamps, associating PDU Sets with a difference between timestamps less than or equal to a threshold, associating PDU Sets with a difference between timestamps equal to an offset value, and associating PDU Sets with a difference between timestamps within a threshold range; and / or, the PDU Set SN-based identification includes at least one of the following methods: associating PDU Sets with the same PDU Set SNs, associating PDU Sets with a difference between PDU Set SNs less than or equal to a threshold, associating PDU Sets with a difference between PDU Set SNs equal to an offset value, and associating PDU Sets with a difference between PDU Set SNs within a threshold range.

[0049] In combination with the second aspect or any implementation thereof, in some other implementations, the method further includes: the user plane function network element obtains fourth indication information, and the fourth indication information is used to instruct the user plane function network element to mark an associated PDU Set.

[0050] In combination with the second aspect or any implementation manner thereof, in some other implementation manners, the first indication information includes an identifier of the first business flow and an identifier of the second business flow; or, the first indication information includes an identifier of the first business flow, an identifier of the first session to which the first business flow belongs, an identifier of the first terminal device to which the first session belongs, an identifier of the second business flow, an identifier of the second session to which the second business flow belongs, and / or an identifier of the second terminal device to which the second session belongs.

[0051] On the third aspect, a communication method is provided, which can be executed by a user plane function network element. Unless otherwise specified, "user plane function network element" can refer to the user plane function network element itself, or it can refer to a device that can support the user plane function network element to realize its function. For the sake of convenience of description, the user plane function network element will be used for description below.

[0052] The method includes: a user plane function network element obtains fifth indication information, where the fifth indication information is used to indicate the association information added by the user plane function network element to the first service flow, and the association information is used by the access network device to determine the associated PDU Set between the first service flow and the second service flow; the user plane function network element receives the first PDU Set of the first service flow; the user plane function network element adds association information to the first PDU Set based on the fifth indication information; and the user plane function network element sends the first PDU Set to the access network device.

[0053] Based on the above method, the user plane functional network element can obtain information indicating the association information to be added to the first service flow, and then add specific association information to the PDU Set in the first service flow based on the obtained information. Based on this, in a scenario where multiple service flows that need to be transmitted synchronously correspond to multiple user plane functional network elements, the multiple user plane functional network elements can add specific association information to the service flows, thereby ensuring that the PDU Sets associated with the multiple service flows carry the same association information, allowing the access network device to synchronously transmit the PDU Sets carrying the same association information, thereby ensuring the synchronous transmission of multiple service flows.

[0054] In combination with the third aspect, in some implementations, the fifth indication information includes a third timestamp corresponding to the first service flow and a third PDU Set SN corresponding to the third timestamp, and the association information added by the user plane functional network element to the first PDU Set is the first PDU Set SN; adding association information to the first PDU Set according to the fifth indication information includes: adding the first PDU Set SN to the first PDU Set according to the third timestamp, the third PDU Set SN and the first timestamp carried by the first PDU Set.

[0055] Based on the above implementation, the user plane functional network element can add a PDU Set SN to the current PDU Set based on the pre-acquired timestamp, the PDU Set SN corresponding to the timestamp, and the timestamp carried by the current PDU Set. In this way, in a scenario where multiple service flows that need to be transmitted synchronously correspond to multiple user plane functional network elements, as long as the timestamp corresponding to each service flow and the PDU Set SN corresponding to the timestamp are designed, it can be ensured that the PDU Sets associated with multiple service flows carry the same PDU Set SN, allowing the access network device to determine the associated PDU Sets in multiple service flows, thereby enabling the access network device to synchronously transmit PDU Sets carrying the same PDU Set SN, thereby ensuring the synchronous transmission of multiple service flows.

[0056] In combination with the third aspect or any implementation manner thereof, in some other implementation manners, the method further includes: obtaining periodic information, the periodic information being used to indicate the time interval between two adjacent PDU Sets of the first service flow; adding a second PDU Set SN to the first PDU Set according to the third timestamp, the third PDU Set SN and the first timestamp carried by the first PDU Set, including: adding the first PDU Set SN to the first PDU Set according to the third timestamp, the third PDU Set SN, the first timestamp and the periodic information.

[0057] In combination with the third aspect or any implementation manner thereof, in some other implementation manners, the fifth indication information includes the offset value of the PDU Set SN corresponding to the first service flow, and the associated information added by the user plane functional network element to the first PDU Set is the first PDU Set SN; adding associated information to the first PDU Set according to the fifth indication information includes: adding the first PDU Set SN to the PDU Set according to the offset value and the fourth PDU Set SN carried by the first PDU Set, and the first PDU Set SN is offset by the offset value relative to the fourth PDU Set SN.

[0058] Based on the above implementation, the user plane functional network element can adjust the PDU Set SN carried by the current PDU Set based on the PDU Set SN offset value obtained in advance, and add the adjusted PDU Set SN to the current PDU Set. In this way, in a scenario where multiple service flows that need to be transmitted synchronously correspond to multiple user plane functional network elements, as long as the offset value that needs to be adjusted for each service flow is designed, it can be ensured that the PDU Sets associated with the multiple service flows carry the same PDU Set SN, allowing the access network device to determine the associated PDU Sets in the multiple service flows, so that the access network device can synchronously transmit the PDU Sets carrying the same PDU Set SN, thereby achieving synchronous transmission guarantee for multiple service flows.

[0059] Fourthly, a communication method is provided, which can be executed by an application function network element. Unless otherwise specified, "user plane function network element" can refer to the application function network element itself, or it can refer to a device that can support the application function network element to realize its function. For the sake of convenience of description, the application function network element will be used for description below.

[0060] The method includes: an application function network element determines synchronization assistance information, where the synchronization assistance information includes first indication information, and the first indication information is used to indicate that a first service flow and a second service flow are associated; and the application function network element sends the synchronization assistance information to a policy control function network element.

[0061] Based on the above method, the application function network element can provide synchronization auxiliary information for the synchronous transmission of PDU Sets associated with multiple service flows, which helps to achieve synchronous transmission guarantee of multiple service flows.

[0062] In combination with the fourth aspect, in some implementations, the synchronization assistance information includes second indication information, and the second indication information is used to indicate the synchronization requirement between the first business flow and the second business flow.

[0063] Based on the above implementation method, the application function network element can provide the synchronization requirement for the transmission of PDU Sets associated with multiple business flows. This synchronization requirement is more in line with the actual needs of multiple business flows and helps to achieve synchronous transmission guarantee of multiple business flows.

[0064] In combination with the fourth aspect or any implementation thereof, in some other implementations, the synchronization requirement includes the maximum value of the transmission delay difference between the PDU Sets associated with the first service flow and the second service flow.

[0065] In combination with the fourth aspect or any implementation manner thereof, in other implementation manners, the synchronization assistance information further includes at least one of the following information: an offset value, third indication information, fourth indication information, fifth indication information, or sixth indication information. The offset value is an offset value between the associated information of the associated PDU Set between the first service flow and the second service flow; the third indication information is used to instruct the user plane function network element to identify the associated PDU Set; the fourth indication information is used to instruct the user plane function network element to mark the associated PDU Set; the fifth indication information is used to instruct the user plane function network element to add associated information to the first service flow and / or to the second service flow, and the associated information is used to determine the associated PDU Set between the first service flow and the second service flow; the sixth indication information is used to instruct the user plane function network element to add the associated information carried by the PDU Set to the GTP-U header.

[0066] Based on the above implementation, the application function network element can provide more information for the synchronous transmission of PDU Sets associated with multiple service flows, which helps to ensure the synchronous transmission of multiple service flows.

[0067] In combination with the fourth aspect or any implementation thereof, in some other implementations, the third indication information is also used to indicate a method in which the user plane function network element identifies the associated PDU Set, and the method is any one of the following methods: timestamp-based identification or PDU Set SN-based identification.

[0068] In combination with the fourth aspect or any implementation manner thereof, in some other implementation manners, the fifth indication information includes the offset value of the PDU Set SN corresponding to the first business flow and / or the offset value of the PDU Set SN corresponding to the second business flow, the PDU Set SN offset value corresponding to the first business flow is the offset value of the PDU Set SN added by the user plane functional network element to the PDU Set of the first business flow relative to the PDU Set SN added by the application server to the PDU Set of the first business flow, and the PDU Set SN offset value corresponding to the second business flow is the offset value of the PDU Set SN added by the user plane functional network element to the PDU Set of the second business flow relative to the PDU Set SN added by the application server to the PDU Set of the second business flow.

[0069] Based on the above implementation, the application function network element can provide a timestamp and a PDU Set SN corresponding to the timestamp, so that the user plane function network element can add a PDU Set SN to the current PDU Set based on the timestamp obtained in advance, the PDU Set SN corresponding to the timestamp, and the timestamp carried by the current PDU Set. In this way, in a scenario where multiple service flows that need to be transmitted synchronously correspond to multiple user plane function network elements, as long as the timestamp corresponding to each service flow and the PDU Set SN corresponding to the timestamp are designed, it can be ensured that the PDU Sets associated with the multiple service flows carry the same PDU Set SN, so that the access network device can determine the associated PDU Sets in the multiple service flows, so that the access network device can synchronously transmit the PDU Sets carrying the same PDU Set SN, thereby achieving synchronous transmission guarantee for multiple service flows.

[0070] In combination with the fourth aspect or any implementation thereof, in some other implementations, the fifth indication information includes: a third timestamp corresponding to the first service flow and a first PDU Set SN corresponding to the third timestamp, and / or a fourth timestamp corresponding to the second service flow and a third PDU Set SN corresponding to the fourth timestamp.

[0071] Based on the above implementation method, the application function network element can provide a PDU Set SN offset value, so that the user plane function network element can adjust the PDU Set SN carried by the current PDU Set based on the PDU Set SN offset value obtained in advance, and add the adjusted PDU Set SN to the current PDU Set. In this way, in a scenario where multiple service flows that need to be transmitted synchronously correspond to multiple user plane function network elements, as long as the offset value that needs to be adjusted for each service flow is designed, it can be ensured that the PDU Sets associated with the multiple service flows carry the same PDU Set SN, so that the access network device can determine the associated PDU Sets in the multiple service flows, so that the access network device can synchronously transmit the PDU Sets carrying the same PDU Set SN, thereby achieving synchronous transmission guarantee for multiple service flows.

[0072] In combination with the fourth aspect or any implementation manner thereof, in some other implementation manners, the synchronization auxiliary information includes the sixth indication information, and the method further includes: the application function network element receives first configuration information from the application service provider, and the first configuration information is used to indicate the synchronous transmission of the first service flow and the second service flow of the service; the application function network element sends second configuration information to the application server based on the first configuration information, and the second configuration information is used to indicate the addition of the same association information to the PDU Set associated between the first service flow and the second service flow.

[0073] Based on the above implementation, a solution can be provided at the application layer to ensure the synchronous transmission of multiple business flows.

[0074] In combination with the fourth aspect or any implementation thereof, in some other implementations, the second configuration information is further used to indicate a synchronization type, and the synchronization type is single-user synchronization or multi-user synchronization. The single-user synchronization indicates that the first service flow and the second service flow are service flows of the same user, and the multi-user synchronization indicates that the first service flow and the second service flow are service flows of different users.

[0075] In the fifth aspect, a communication method is provided, which can be executed by an application service provider. Unless otherwise specified, "application service provider" can refer to the application service provider itself or a device that can support the application service provider to implement its functions. For the sake of convenience, the application service provider will be used as the description below.

[0076] The method includes: an application service provider determining first configuration information, where the first configuration information is used to instruct synchronous transmission of a first service flow and a second service flow of a service; and the application service provider sending the first configuration information to an application function.

[0077] Based on the above implementation, a solution can be provided at the application layer to ensure the synchronous transmission of multiple business flows.

[0078] In the sixth aspect, a communication method is provided, which can be executed by an application server. Unless otherwise specified, "application server" can refer to the application server itself or a device that can support the application server to implement its functions. For the sake of convenience, the application server will be used as the description below.

[0079] The method includes: an application server receiving second configuration information from an application function, where the second configuration information is used to indicate adding the same association information to a PDU Set associated between a first service flow and a second service flow of a service; and the application server adding the same association information to a first PDU Set of the first service flow and a second PDU Set of the second service flow based on the second configuration information.

[0080] Based on the above implementation, a solution can be provided at the application layer to ensure the synchronous transmission of multiple business flows.

[0081] In combination with the sixth aspect, in some implementations, the associated information is PDU Set SN.

[0082] In combination with the sixth aspect or any implementation thereof, in some other implementations, the second configuration information is also used to indicate a synchronization type, and the synchronization type is single-user synchronization or multi-user synchronization. The single-user synchronization indicates that the first service flow and the second service flow are service flows of the same user, and the multi-user synchronization indicates that the first service flow and the second service flow are service flows of different users.

[0083] In the seventh aspect, a communication method is provided, which can be executed by a user plane function network element. Unless otherwise specified, "user plane function network element" can refer to the user plane function network element itself, or it can refer to a device that can support the user plane function network element to realize its function. For the sake of convenience of description, the user plane function network element will be used for description below.

[0084] The method includes: a user plane function network element receives a first PDU Set of a first service flow and a second PDU Set of a second service flow, the first PDU Set carries first association information, and the second PDU Set carries second association information, and the first association information and the second association information are used to determine that the first PDU Set is associated with the second PDU Set; the user plane function network element adds the first association information to the GTP-U header of the first PDU Set, and adds the second association information to the GTP-U header of the second PDU Set; the user plane function network element sends the first PDU Set and the second PDU Set to the access network device.

[0085] Based on the above method, the user plane functional network element can add the association information carried in the PDU Set to the GTP-U layer, so that the access network device can obtain the association information, and then identify the PDU Set associated with multiple service flows based on the association information, and then synchronously transmit the associated PDU Set, thereby achieving synchronous transmission guarantee of multiple service flows.

[0086] In combination with the seventh aspect, in some implementations, the method further includes: the user plane function network element receives sixth indication information, and the sixth indication information is used by the user plane function network element to add the association information carried by the PDU Set to the GTP-U header.

[0087] In combination with the seventh aspect or any implementation thereof, in some other implementations, the first association information and the second association information are PDU Set SN or timestamp.

[0088] In an eighth aspect, a communication method is provided, the method including the method steps performed by the access network device in the first aspect or its implementation, the method steps performed by the user plane function network element in the second aspect or its implementation, and the method steps performed by the application function network element in the fourth aspect or its implementation, or the method including the method steps performed by the access network device in the first aspect or its implementation, the method steps performed by the user plane function network element in the third aspect or its implementation, and the method steps performed by the application function network element in the fourth aspect or its implementation, or the method including the method steps performed by the access network device in the first aspect or its implementation, the method steps performed by the user plane function network element in the seventh aspect or its implementation, and the method steps performed by the application function network element in the fourth aspect or its implementation, or the method including the method steps performed by the access network device in the first aspect or its implementation, the method steps performed by the user plane function network element in the seventh aspect or its implementation, the method steps performed by the application function network element in the fourth aspect or its implementation, the method steps performed by the application service provider in the fifth aspect or its implementation, the method steps performed by the application server in the sixth aspect or its implementation, and the method steps performed by the application function network element in the fourth aspect or its implementation.

[0089] In the ninth aspect, a communication device is provided, which may be an access network device, a user plane function network element, an application function network element, an application service provider or an application server, or may be a device, module, circuit or chip configured in an access network device, a user plane function network element, an application function network element, an application service provider or an application server, or may be a device that can be used in conjunction with an access network device, a user plane function network element, an application function network element, an application service provider or an application server. In one design, the communication device may include a module that corresponds one-to-one to the method / operation / step / action described in the above-mentioned corresponding aspects or their implementation methods, and the module may be a hardware circuit, software, or a combination of a hardware circuit and software. In one design, the communication device may include a processing module and a communication module.

[0090] The sending module is used to execute the sending action in the method described above, and the processing module is used to execute the processing-related actions in the method described above.

[0091] In a tenth aspect, a communication device is provided, comprising a processing circuit and a storage medium, wherein the storage medium stores instructions, and when the instructions are executed by the processing circuit, the method in any of the above aspects or any possible implementation thereof is implemented.

[0092] Optionally, the communication device may be an access network device, a user plane function network element, an application function network element, an application service provider, or an application server.

[0093] Optionally, the communication device may be a chip applied to an access network device, a user plane function network element, an application function network element, an application service provider, or an application server.

[0094] In an eleventh aspect, a communication device is provided, comprising a processing circuit, wherein the processing circuit is used to process data and / or information so that the method in any of the above aspects or its implementation is implemented. Optionally, the device may also include a memory, wherein the memory is used to store programs or instructions. Optionally, the communication device may also include a communication interface, wherein the communication interface is used to receive data and / or information and transmit the received data and / or information to the processing circuit. Optionally, the communication interface is also used to output data and / or information processed by the processing circuit. The communication interface may also be referred to as an interface circuit or a transceiver circuit.

[0095] Optionally, the communication device may be an access network device, a user plane function network element, an application function network element, an application service provider, or an application server.

[0096] Optionally, the communication device may be a chip applied to an access network device, a user plane function network element, an application function network element, an application service provider, or an application server.

[0097] In a twelfth aspect, a chip system is provided, comprising a processing circuit, wherein the processing circuit is configured to execute a program or instruction to implement the method of any of the above aspects or its implementations. Optionally, the chip system may further include an input / output interface. Optionally, the chip system may further include a memory configured to store the program or instruction. The processing circuit may also be referred to as a logic circuit.

[0098] In a thirteenth aspect, a computer-readable storage medium is provided, wherein the computer-readable storage medium includes instructions, and when the instructions are executed by a processing circuit, the method in any of the above aspects or its implementation method is implemented.

[0099] In a fourteenth aspect, a computer program product is provided, which includes computer program code or instructions. When the computer program code or instructions are executed, the method in any of the above aspects or its implementation methods is implemented.

[0100] In the fifteenth aspect, a communication system is provided, which includes a combination of one or more of the following devices: a communication device that performs the first aspect or any possible implementation of the first aspect, or a communication device that performs the second aspect or any possible implementation of the second aspect, a communication device that performs the third aspect or any possible implementation of the third aspect, a communication device that performs the fourth aspect or any possible implementation of the fourth aspect, a communication device that performs the fifth aspect or any possible implementation of the fifth aspect, a communication device that performs the sixth aspect or any possible implementation of the sixth aspect, or a communication device that performs the seventh aspect or any possible implementation of the seventh aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0101] FIG1 is a schematic diagram of a communication system applicable to an embodiment of the present application.

[0102] FIG2 is a schematic flow chart of a communication method 200 provided in an embodiment of the present application.

[0103] FIG3 is a schematic flowchart of a communication method 300 provided in an embodiment of the present application.

[0104] FIG4 is a schematic flow chart of a communication method 400 provided in an embodiment of the present application.

[0105] FIG5 is a schematic flowchart of a communication method 500 provided in an embodiment of the present application.

[0106] FIG6 is a schematic flowchart of a communication method 600 provided in an embodiment of the present application.

[0107] FIG7 is a schematic flowchart of a communication method 700 provided in an embodiment of the present application.

[0108] FIG8 is a schematic flowchart of a communication method 800 provided in an embodiment of the present application.

[0109] FIG9 is a schematic flowchart of a communication method 900 provided in an embodiment of the present application.

[0110] FIG10 is a schematic flowchart of a communication method 1000 provided in an embodiment of the present application.

[0111] FIG11 is a schematic structural diagram of a device provided in an embodiment of the present application.

[0112] FIG12 is another schematic structural diagram of the device provided in an embodiment of the present application.

[0113] FIG13 is a schematic diagram of a chip system provided in an embodiment of the present application. DETAILED DESCRIPTION

[0114] To facilitate understanding of the embodiments of the present application, the following explanations are made before introducing the embodiments of the present application.

[0115] "Indication" includes direct indication (also known as explicit indication) and implicit indication. Direct indication of information A refers to the inclusion of information A; implicit indication of information A refers to the indication of information A through the correspondence between information A and information B, as well as the direct indication of information B. The correspondence between information A and information B can be predefined, pre-stored, pre-burned, or pre-configured. Information C is used to determine information D, including situations where information D is determined solely based on information C or based on information C and other information. Furthermore, information C can also be used to determine information D indirectly, for example, when information D is determined based on information E, and information E is determined based on information C. "Network element A sends information A to network element B" can be understood as network element B being the destination of information A or an intermediate network element in the transmission path between the destination and the network element, and can include direct or indirect transmission of information to network element B. "Network element B receives information A from network element A" can be understood as network element A being the source of information A or an intermediate network element in the transmission path between the source and the network element, and can include direct or indirect receipt of information from network element A. Information may undergo necessary processing between the source and destination of information transmission, such as format changes, but the destination can still understand the valid information from the source. The various numerical numbers such as first, second, etc. are merely distinctions for ease of description and are not intended to limit the scope of the embodiments of this application, for example, to distinguish between different messages, different information, etc. "Pre-definition" can be implemented by pre-saving corresponding codes, tables, or other methods that can be used to indicate relevant information in the device, and this application does not limit its specific implementation. The "protocol" involved may refer to a standard protocol in the field of communications, such as the Long Term Evolution (LTE) protocol, the New Radio (NR) protocol, and related protocols used in future communication systems, but this application does not limit this. Words such as "exemplary," "for example," "exemplarily," and "as (another) example" are used to indicate examples, illustrations, or explanations. Any embodiment or design described as an "example" in this application should not be construed as preferred or advantageous over other embodiments or designs. The terms "including," "comprising," "having," and their variations all mean "including but not limited to," unless otherwise specifically emphasized. "Multiple" refers to two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships can exist. For example, A and / or B can mean: the existence of A alone, the existence of A and B at the same time, and the existence of B alone, where A and B can be singular or plural. The character " / " generally indicates that the previous and next associated objects are in an "or" relationship. "At least one of the following items" or similar expressions refers to any combination of these items, including any combination of single or plural items.For example, at least one of a, b, and c can represent: a, or b, or c, or a and b, or a and c, or b and c, or a, b, and c. A, b, and c can each be single or multiple. Phrases such as "when," "in the case of," "if," and "if" all imply that the device will perform a corresponding action under certain objective circumstances. They do not limit the time, do not require the device to perform a judgment action during implementation, and do not imply any other limitations.

[0116] In addition, the network architecture and business scenarios described in the embodiments of the present application are intended to more clearly illustrate the technical solutions of the embodiments of the present application, and do not constitute a limitation on the technical solutions provided in the embodiments of the present application. Ordinary technicians in this field can know that with the evolution of network architecture and the emergence of new business scenarios, the technical solutions provided in the embodiments of the present application are also applicable to similar technical problems.

[0117] A communication system to which the embodiments of the present application can be applied is described below.

[0118] The embodiments of the present application can be applied to various communication systems, such as LTE systems, frequency division duplex (FDD) systems, time division duplex (TDD) systems, universal mobile telecommunication systems (UMTS), worldwide interoperability for microwave access (WiMAX) communication systems, fifth generation (5G) systems or NR systems, sixth generation (6G) systems or future communication systems. The 5G mobile communication system described in this application includes a non-standalone (NSA) 5G mobile communication system or a standalone (SA) 5G mobile communication system. The communication system may also be a public land mobile network (PLMN) network, a device-to-device (D2D) communication system, a machine-to-machine (M2M) communication system, an Internet of Things (IoT) communication system, a vehicle to everything (V2X) communication system, an uncrewed aerial vehicle (UAV) communication system, or other communication systems.

[0119] For example, Figure 1 illustrates a network architecture diagram applicable to embodiments of the present application. As shown in Figure 1 , the network architecture may specifically include three parts: a terminal device part, a data network (DN), and an operator network part. The following briefly describes the functions of the network elements in each part.

[0120] The terminal device portion may include a terminal device, which may also be referred to as user equipment (UE). The terminal device in this application is a device with wireless transceiver capabilities that can communicate with one or more core network (CN) devices via an access network device (or also referred to as an access device) in a radio access network (RAN). The terminal device may also be referred to as an access terminal, terminal, user unit, user station, mobile station, mobile station, remote station, remote terminal, mobile device, user terminal, user agent, or user device, etc. The terminal device may be deployed on land, including indoors or outdoors, handheld or vehicle-mounted; it may also be deployed on water (e.g., ships); it may also be deployed in the air (e.g., airplanes, balloons, and satellites). The terminal device may be a cellular phone, a cordless phone, a session initiation protocol (SIP) phone, a smart phone, a mobile phone, a wireless local loop (WLL) station, a personal digital assistant (PDA), etc. Alternatively, the terminal device may also be a handheld device with wireless communication capabilities, a computing device, or other device connected to a wireless modem, an in-vehicle device, a wearable device, a drone device, or an Internet of Things, a terminal in the Internet of Vehicles, a terminal in any form in a 5G network and future networks, a relay user device, or a terminal in a future evolved 6G network, etc. Among them, the relay user device may be, for example, a 5G residential gateway (RG). For example, the terminal device may be a virtual reality (VR) terminal, an augmented reality (AR) terminal, a wireless terminal in industrial control, a wireless terminal in self-driving, a wireless terminal in remote medical care, 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. The terminal device here refers to a 3GPP terminal. The embodiments of the present application do not limit the specific technology and specific device form adopted by the terminal device.

[0121] A data network, also known as a packet data network (PDN), is typically a network located outside of an operator's network, such as a third-party network. Of course, in some implementations, the DN can also be deployed by the operator, meaning the DN is part of the PLMN. An operator's network can access multiple data network DNs, which can deploy a variety of services and provide data and / or voice services to terminal devices. Terminal devices can also access data network DNs through the operator's network and use operator services deployed on the data network DNs, and / or services provided by third parties.

[0122] The operator network part includes but is not limited to the (radio) access network (R)AN) part and the core network (CN) part.

[0123] (R)AN can be regarded as a sub-network of the operator network, and is an implementation system between the service node and the terminal device in the operator network. To access the operator network, the terminal device must first pass through the (R)AN, and then connect to the service node of the operator network through the (R)AN. The access network device (RAN device) in the embodiment of the present application is a device that provides wireless communication functions for the terminal device, and can also be called a network device. The RAN device includes but is not limited to: the next generation node base station (gNB) in the 5G system, the evolved node B (eNB) in the long term evolution (LTE), the radio network controller (RNC), the node B (NB), the base station controller (BSC), the base transceiver station (BTS), the home base station (for example, home evolved node B, or home node B, HNB), the base band unit (BBU), the transmission point (TRP), the transmitting point (TP), the small base station device (pico), the mobile switching center, or the network equipment in the future network. In systems using different wireless access technologies, the names of devices with access network device functions may be different. The embodiments of this application do not limit the specific technologies and specific device forms used by the access network devices.

[0124] The CN part includes but is not limited to the following network functions (NF): user plane function (UPF), network exposure function (NEF), network function repository function (NRF), policy control function (PCF), UDM, UDR, network data analytics function (NWDAF), authentication server function (AUSF), access and mobility management function (AMF), session management function (SMF) and application function (AF).

[0125] The following is a brief description of the NF functions included in CN.

[0126] 1. UPF is the gateway for communication between the operator network and the data network DN. It mainly provides user plane functions such as forwarding and processing of user messages, connection with DN, session anchor point, and quality of service (QoS) policy execution.

[0127] 2. NEF is a control plane function that is primarily used to securely expose services and capabilities provided by 3GPP network functions to external parties (such as AF). NEF also allows authenticated and authorized application functions to securely provide information in the 3GPP network.

[0128] 3. NRF is a control plane function that can be used to maintain real-time information of network functions and services in the network.

[0129] 4. PCF is the control plane function, which supports a unified policy framework to govern network behavior, provide policy rules to other control functions, and contract information related to policy decisions.

[0130] 5. UDM is a control plane function, which is mainly responsible for storing the contract data of contracted users in the operator network.

[0131] 6. UDR is a control plane function, mainly responsible for data storage and retrieval, such as providing the UDM with the function of storing and retrieving contract data, providing the PCF with the function of storing and retrieving policy data, and storing and retrieving the user's NF group ID information.

[0132] 7. AUSF is a control plane function, usually used for level 1 authentication, that is, authentication between terminal equipment (subscribers) and operator networks.

[0133] 8. AMF is a control plane function that is mainly responsible for access control and mobility management of terminal devices accessing the operator's network, such as mobile state management, allocation of user temporary identity, authentication and authorization of users, etc.

[0134] 9. SMF is the control plane function, which is mainly responsible for session management (such as session establishment, modification and release), selection and control of UPF network functions, service and session continuity (SSC) mode selection, roaming and other session-related functions.

[0135] 10. AF is a control plane function that provides application layer information. AFs are divided into two main categories: the first category is deployed by the operator and is considered to be trusted by the operator. This type of AF can directly interact with other network functions in the network; the second category is AF that the operator does not allow direct access to network functions, such as third-party AFs. This type of AF can interact with other network functions in the NEF network.

[0136] In Figure 1, Nnef, Nnrf, Npcf, Nudm, Nudr, Nausf, Namf, Nsmf, N1, N2, N3, N4, N6 and N9 are interface serial numbers. For example, the meaning of the above interface serial numbers can be found in the meaning defined in the 3GPP standard protocol, and this application does not limit the meaning of the above interface serial numbers. It should be noted that the interface name between the various network functions in Figure 1 is only an example. In a specific implementation, the interface name of the system architecture may also be other names, and this application does not limit this. In addition, the name of the message (or signaling) transmitted between the above-mentioned network elements is also only an example and does not constitute any limitation on the function of the message itself. In the network architecture shown in Figure 1, the network elements can communicate with each other through interfaces. The interface between the network elements can be a point-to-point interface or a service-oriented interface, which is not limited by this application.

[0137] It should be understood that the network architecture shown above is only an exemplary illustration, and the network architecture applicable to the embodiments of the present application is not limited to this. Any network architecture that can realize the functions of the above-mentioned network elements is applicable to the embodiments of the present application.

[0138] It should also be understood that the AMF, SMF, UPF, PCF, UDM, AUSF, UDR, NEF, NRF, AF and other functions or network elements shown in Figure 1 can be understood as network elements for implementing different functions, for example, they can be combined into network slices as needed. These network elements can be independent devices, or they can be integrated into the same device to implement different functions, or they can be network elements in hardware devices, or they can be software functions running on dedicated hardware, or they can be virtualized functions instantiated on a platform (for example, a cloud platform). This application does not limit the specific form of the above network elements.

[0139] It should also be understood that the above naming is defined only to facilitate the distinction between different functions and should not constitute any limitation to this application. This application does not exclude the possibility of adopting other naming in 6G networks and other future networks. For example, in a 6G network, some or all of the above network elements may continue to use the terminology used in 5G, or may adopt other names.

[0140] To facilitate understanding of the embodiments of the present application, several concepts or terms involved in the embodiments of the present application are briefly explained below.

[0141] The concepts and terms introduced below are explained with reference to those specified in the protocol. However, this does not mean that the embodiments of this application are applicable only to existing systems. The concepts and terms involved in the embodiments of this application can be applied to future systems. Furthermore, the specific names of the concepts and terms (for example, concepts and terms describing functionality) may be adjusted as future systems develop.

[0142] 1. QoS flow

[0143] When there is a need for business communication, the terminal device will establish a data connection session (such as a protocol data unit (PDU) session, which will be explained later using the PDU session as an example). The PDU session can have one or more QoS flows, and the business data flow or business flow is carried on the QoS flow. Specifically, the terminal device obtains the Internet Protocol (IP) address through the PDU session establishment process to interact with the business server and realize business communication. Based on the business flow description information, 5GS maps the business to different QoS flows and performs corresponding QoS processing on the business flow.

[0144] 2. QoS flow identifier (QFI)

[0145] QFI is a unique identifier for different QoS flows within a PDU session.

[0146] 3. QoS rule

[0147] QoS rules are QoS configurations sent to the terminal device side. QoS rules can include at least one of the following information: QFI, packet filter (such as IP 5-tuple) or QoS rule identifier.

[0148] 4. QoS Profile

[0149] The QoS profile is the QoS configuration sent to the RAN side. Specifically, it may include at least one of the following information: 5G QoS Identifier (5QI), allocation and retention priority (ARP), guaranteed flow bit rate (GFBR) / maximum flow bit rate (MFBR) or QFI, etc.

[0150] 5. N4 rule

[0151] N4 rules are traffic flow identification and processing rules sent to the UPF side. They can include at least one of the following information: packet detection rules, usage reporting rules, or QoS enforcement rules. QoS enforcement rules can include at least one of the following information: maximum bit rate, guaranteed bit rate, or averaging window.

[0152] 6. Protocol Data Unit Collection

[0153] The QoS mechanism provides service guarantees at the packet level, such as through the packet error rate (PER) or packet delay budget (PDB) within QoS parameters. Packets for a particular service are mapped to the same QoS flow and individually processed and transmitted using the same QoS parameters. In other words, all packets within a QoS flow receive the same, undifferentiated treatment during transmission.

[0154] In the research of extended reality and media services (XRM), real-time media services, such as the currently emerging virtual reality (VR), augmented reality (AR), mixed reality (MR), or cloud gaming, have extremely stringent requirements for end-to-end latency. Furthermore, the data processing granularity of these services during encoding, rendering, and decoding is no longer limited to packets. For example, when the upper service layer (e.g., the media layer) at the sending end encodes service data, it often encodes it at a granularity such as media frames or fragments. This means that media frames or fragments can be encoded independently. At the same time, the receiving end of the service also decodes and displays the received service data at the same granularity such as media frames or fragments. Data units such as media frames or fragments often contain multiple data packets. If a data packet within a data unit such as a media frame or fragment is lost or damaged, the entire data unit may be difficult to correctly decode and display.

[0155] To this end, the standard introduces a QoS mechanism at the PDU Set granularity, which provides the loss rate or latency requirements at the PDU Set granularity. The communication system identifies the relationship between different data packets and PDU Sets, clarifies which data packets a PDU Set contains, and schedules, processes, and transmits all data packets in the PDU Set as a whole based on the QoS parameters at the PDU Set granularity, thereby ensuring the user's service experience.

[0156] 7. Multimodal Services

[0157] Multimodal services are generally used to refer to services that include multiple modal service streams. For example, a multimodal service stream can be a service stream with different modalities, such as an audio stream, a video stream, a tactile stream, a temperature stream, and / or a brightness stream. For example, a common multimedia service may include an audio stream, a video stream, and / or control data.

[0158] In order to provide a good and consistent service experience, synchronous transmission guarantees are required between multiple service flows of multimodal services.

[0159] Table 1 shows an example of synchronization requirements between multiple service flows of a multimodal service.

[0160] Table 1

[0161] As shown in Table 1, multimodal services have certain synchronization delay requirements between audio and haptics or visual and haptics. It should be noted that for each media component, "latency" refers to the latency of that media component compared to other media components. For example, for audio and haptics, the audio latency of 50 milliseconds (ms) is relative to the haptics.

[0162] Currently, in the discussion of the 3rd Generation Partnership Project (3GPP) standards, support for multimodal services has been preliminarily determined, but how to achieve synchronous transmission guarantee between multiple service flows of multimodal services has not been clearly discussed and defined.

[0163] In response to the above problems, embodiments of the present application provide a communication method and a communication device, in order to provide a solution for ensuring synchronous transmission between multiple service flows of a multimodal service.

[0164] The following describes the method embodiments of the present application.

[0165] The embodiments of the present application can be applied to scenarios where multiple business flows that need to be guaranteed by synchronous transmission are transmitted through the same UPF, and can also be applied to scenarios where multiple business flows that need to be guaranteed by synchronous transmission are transmitted through multiple UPFs. The solutions for the two scenarios are described below.

[0166] Scenario 1: Multiple service flows that require synchronous transmission assurance are transmitted through the same UPF

[0167] FIG2 is a schematic flow chart of a communication method 200 provided in an embodiment of the present application.

[0168] Method 200 can be performed by access network equipment, UPF, SMF, PCF and / or AF. Unless otherwise specified, "access network equipment", "UPF", "SMF", "PCF" or "AF" may refer to the access network equipment, UPF, SMF, PCF or AF itself, or may refer to a device that can support the access network equipment, UPF, SMF, PCF or AF to implement its functions. For the sake of convenience of description, the access network equipment, UPF, SMF, PCF or AF will be used for description below.

[0169] Method 200 includes at least part of the following.

[0170] Optionally, in step 201, the AF determines synchronization assistance information.

[0171] Among them, the synchronization auxiliary information is used for the synchronous transmission of the first business flow and the second business flow. It should be noted that there may be two or more business flows that need to be guaranteed by synchronous transmission. The implementation of this application only describes the scheme of the embodiment of this application by taking the first business flow and the second business flow as examples. The embodiment of this application can be applied to the synchronous transmission guarantee of more business flows. It should also be noted that the multiple business flows that need to be guaranteed by synchronous transmission in the embodiment of this application can be multiple business flows of the same business, or multiple business flows of the same application. The multiple business flows can be multiple business flows for the same terminal device, or multiple business flows for multiple terminal devices, without limitation. It should also be noted that the various embodiments of this application can be applied to the synchronous transmission guarantee of multiple business flows of multimodal services, and can also be applied to other scenarios of multiple business flows that need to be guaranteed by synchronous transmission, without limitation.

[0172] The synchronization assistance information may include first indication information. The first indication information is used to indicate that the first service flow and the second service flow are associated. The first service flow and the second service flow are associated, that is, the first service flow and the second service flow need to be synchronized and transmitted.

[0173] Exemplarily, the first indication information may be flow description information, used to identify the first service flow and the second service flow that require synchronization. For example, the first indication information may include description information such as the IP quintuple or IP triplet of the first service flow, and description information such as the IP quintuple or IP triplet of the second service flow. In another example, the first indication information may include an identifier of the first service flow and an identifier of the second service flow, such as an application identifier of the first service flow and an application identifier of the second service flow. In another example, when the first service flow is a service flow for a first terminal device and the second service flow is a service flow for a second terminal device, the first indication information may include an identifier of the first service flow, an identifier of the first session to which the first service flow belongs, an identifier of the first terminal device to which the first session belongs, an identifier of the second service flow, an identifier of the second session to which the second service flow belongs, and / or an identifier of the second terminal device to which the second session belongs. In another example, the AF may indicate that the first service flow and the second service flow are associated by carrying the same synchronization identifier in the flow description information of the first service flow and the flow description information of the second service flow, i.e., the first service flow and the second service flow carrying the same synchronization identifier are associated.

[0174] Optionally, the synchronization assistance information may also include second indication information. The second indication information is used to indicate the synchronization requirement between the first service flow and the second service flow. Exemplarily, the synchronization requirement may indicate the maximum value of the transmission delay difference between the PDU Sets associated between the first service flow and the second service flow; or it may indicate the common transmission delay requirement of the PDU Sets associated between the first service flow and the second service flow, that is, the upper limit of the delay for all associated PDU Sets to complete transmission, such as PDU Set#A of the first service flow and PDU Set#B of the second service flow need to be fully transmitted under the delay requirement corresponding to the synchronization requirement, that is, the delay requirement from the reception of the first data packet of PDU Set#A and PDU Set#B to the completion of sending the last data packet. When the synchronization assistance information does not include the second indication information, the synchronization requirement between the first service flow and the second service flow may be determined by the PCF itself, or by the access network device itself. For example, the access network device may transmit the associated PDU Set strictly according to the same transmission delay.

[0175] In addition, it should be noted that there may be two or more PDU Sets in the first business flow and the second business flow that require synchronous transmission guarantee. The implementation of this application only describes the solution of the embodiment of this application using the first PDU Set and the second PDU Set as examples. The embodiment of this application can be applied to the synchronous transmission guarantee of more related PDU Sets.

[0176] Optionally, the synchronization assistance information further includes at least one of the following information: an offset value, third indication information, or fourth indication information.

[0177] The offset value is the offset value between the associated information of the PDU Set associated between the first business flow and the second business flow. For example, PDU Set A of the first business flow is associated with PDU Set B of the second business flow, PDU Set A carries associated information A, and PDU Set B carries associated information B. The offset value is the offset value between associated information A and associated information B. Exemplarily, the associated information here can be the real-time transport protocol (RTP) timestamp, PDU Set SN or other synchronization identifier of the PDU Set. Among them, the RTP timestamp is used to indicate the generation or sending time of the PDU Set carrying the timestamp information. PDU Set SN is used to indicate the order of the PDU Set. The synchronization identifier is used to identify the identification information for synchronization of the PDU Set.

[0178] It should be noted that when an offset value is carried, the offset value also carries identification information for indicating a reference service flow, that is, the offset value is the offset value between the current service flow and the reference service flow.

[0179] The third indication information is used to instruct the UPF to identify the associated PDU Set, that is, to identify the associated PDU Set in the associated service flow. For example, when the UPF identifies the associated PDU Set by default, the synchronization assistance information may not include the third indication information, or the UPF identifies the associated PDU Set in the associated service flow based on the fourth indication information mentioned later. Optionally, the third indication information is further used to indicate the manner in which the UPF identifies the associated PDU Set. When there is only one default identification method, the third indication information may not indicate the manner in which the UPF identifies the associated PDU Set. Exemplarily, the manner in which the UPF identifies the associated PDU Set is any one of the following: identification based on RTP timestamp, or identification based on PDU Set SN, wherein the method based on PDU Set SN identification is applicable to scenarios in which the application server (AS) uses an RTP extension header carrying a PDU Set SN or scenarios in which the application server uses other protocol headers carrying a PDU Set SN or a synchronization identifier.

[0180] The identification based on the RTP timestamp includes at least one of the following methods: associating PDU Sets with the same RTP timestamp, associating PDU Sets with the difference between RTP timestamps less than or equal to a threshold, associating PDU Sets with the difference between RTP timestamps within a threshold range, and associating PDU Sets with the difference between RTP timestamps equal to an offset value. For the method of associating PDU Sets with the same RTP timestamp, the UPF can perform association identification based on the timestamps in the RTP headers of the downlink data packets in the first service flow and the second service flow, and determine the association of PDU Sets with the same RTP timestamp. For the method of associating PDU Sets with the difference between RTP timestamps less than or equal to the threshold K1, the UPF can perform association identification based on the timestamps in the RTP headers of the downlink data packets in the first service flow and the second service flow, and determine the association of PDU Sets with the RTP timestamp difference within the threshold range (0, K1). In this method, the synchronization assistance information can also include the RTP timestamp threshold for identifying the PDU Set association relationship. For the method of associating PDU Sets with the difference between RTP timestamps within the threshold range (M1, N1), the UPF can perform association identification based on the timestamps in the RTP headers of the downlink data packets in the first service flow and the second service flow, and determine the association of PDU Sets with the RTP timestamp difference within the threshold range (M1, N1), where 0 < M1 < N1. For the method of associating PDU Sets with the difference between RTP timestamps equal to the offset value, the UPF can perform association identification based on the timestamps in the RTP headers of the downlink data packets in the first service flow and the second service flow, and determine the association of PDU Sets with the difference between RTP timestamps equal to the offset value. In this method, the synchronization assistance information can also include the offset value.

[0181] The identification based on the PDU Set SN includes at least one of the following methods: associating PDU Sets with the same PDU Set SN, associating PDU Sets with the difference between PDU Set SNs less than or equal to a threshold, associating PDU Sets with the difference between PDU Set SNs within a threshold range, and associating PDU Sets with the difference between PDU Set SNs equal to an offset value. For the method of associating PDU Sets with the same PDU Set SN, the UPF can perform association identification based on the PDU Set SN in the RTP header of the downlink data packets in the first service flow and the second service flow, and determine that the PDU Sets with the same PDU Set SN are associated. For the method of associating PDU Sets with the difference between PDU Set SNs less than or equal to the threshold K2, the UPF can perform association identification based on the PDU Set SN in the RTP header of the downlink data packets in the first service flow and the second service flow, and determine that the PDU Sets with the PDU Set SN difference within the threshold range (0, K2) are associated. In this method, the synchronization assistance information can also include the PDU Set SN threshold for identifying the PDU Set association relationship. For the method of associating PDU Sets with the difference between PDU Set SNs within the threshold range (M2, N2), the UPF can perform association identification based on the PDU Set SN in the RTP header of the downlink data packets in the first service flow and the second service flow, and determine that the PDU Sets with the PDU Set SN difference within the threshold range are associated. In this method, the synchronization assistance information can also include the PDU Set SN threshold range (M2, N2) for identifying the PDU Set association relationship, where 0 < M2 < N2. For the method of associating PDU Sets with the difference between PDU Set SNs equal to the offset value, the UPF can perform association identification based on the PDU Set SN in the RTP header of the downlink data packets in the first service flow and the second service flow, and determine that the PDU Sets with the difference between PDU Set SNs equal to the offset value are associated. In this method, the synchronization assistance information can also include this offset value.

[0182] In the embodiments of the present application, the threshold and the offset value can be interchanged.

[0183] The fourth indication information is used to instruct the UPF to mark the associated PDU Set. For example, when the associated PDU Set is marked by the UPF by default, the synchronization assistance information may not include the fourth indication information. Optionally, the fourth indication information is further used to indicate the manner in which the UPF marks the associated PDU Set. Optionally, the fourth indication information is also used to instruct the UPF to identify the associated PDU Set. When there is only one default marking method, the fourth indication information may not indicate the manner in which the UPF marks the associated PDU Set. Exemplarily, the manner in which the UPF marks the associated PDU Set is any one of the following methods: adding the same association information to the associated PDU Set, where the association information may be the RTP timestamp of the PDU Set, the PDU Set SN or other synchronization identifier.

[0184] Optionally, in step 202, the AF sends synchronization assistance information to the PCF, and correspondingly, the PCF receives the synchronization assistance information from the AF.

[0185] Step 203: The PCF sends first indication information to the SMF according to the received synchronization assistance information. Correspondingly, the SMF receives the first indication information from the PCF.

[0186] Optionally, when the synchronization assistance information also includes second indication information, offset value, third indication information or fourth indication information, the PCF also sends the second indication information, offset value, third indication information or fourth indication information to the SMF, and accordingly, the SMF also receives the second indication information, offset value, third indication information or fourth indication information from the PCF.

[0187] Optionally, if the PCF does not receive synchronization assistance information from the AF, the synchronization assistance information may be locally configured on the PCF side. That is, the PCF independently generates the first indication information, second indication information, offset value, third indication information, or fourth indication information. For example, the operator independently configures the above information for the multimodal service, and the information may be derived from an agreement between the operator and a third-party application vendor.

[0188] Step 204: The SMF sends first indication information to the UPF based on the information received from the PCF. Correspondingly, the UPF receives the first indication information from the SMF.

[0189] Optionally, when the SMF also receives the offset value, the third indication information or the fourth indication information, the SMF also sends the offset value, the third indication information or the fourth indication information to the UPF, and accordingly, the UPF also receives the offset value, the third indication information or the fourth indication information from the SMF.

[0190] It should be noted that the first indication information, offset value, third indication information or fourth indication information sent by SMF to UPF may be the same as or different from the first indication information, offset value, third indication information or fourth indication information received by SMF from PCF, without restriction.

[0191] Step 205: The SMF sends first indication information to the access network device. Correspondingly, the access network device receives the first indication information from the SMF.

[0192] Optionally, when the SMF also receives the second indication information, the SMF also sends the second indication information to the access network device, and accordingly, the access network device also receives the second indication information from the SMF.

[0193] It should be noted that the first indication information or second indication information sent by the SMF to the access network device can be the same as or different from the first indication information or second indication information received by the SMF from the PCF, without limitation.

[0194] Step 206: The UPF receives a first PDU Set of the first service flow and a second PDU Set of the second service flow.

[0195] The first PDU Set carries the third association information, and the second PDU Set carries the fourth association information. The third association information and the fourth association information are used by the UPF to determine that the first PDU Set is associated with the second PDU Set.

[0196] As an example, the third association information is the first PDU Set SN carried by the first PDU Set, and the fourth association information is the second PDU Set SN carried by the second PDU Set.

[0197] As another example, the third associated information is the first RTP timestamp carried by the first PDU Set, and the fourth associated information is the second RTP timestamp carried by the second PDU Set. The first RTP timestamp may indicate the time when the first PDU Set was generated or sent, i.e., the time when the first PDU Set was generated on the application server side or sent from the application server side. The second RTP timestamp may indicate the time when the second PDU Set was generated or sent, i.e., the time when the second PDU Set was generated on the application server side or sent from the application server side.

[0198] Prior to this, the UPF determines that the first business flow and the second business flow are interrelated based on the received first indication information.

[0199] In step 207, the UPF adds association information to the first PDU Set and / or the second PDU Set according to the first indication information, the third association information, and the fourth association information.

[0200] The UPF adds association information to the first PDU Set and / or the second PDU Set for the access network device to determine that the first PDU Set is associated with the second PDU Set.

[0201] The first indication information is used to indicate that the first service flow and the second service flow are associated. The first service flow and the second service flow are associated, that is, the first service flow and the second service flow need to be synchronized and transmitted. The first indication information can specifically be the identifier of the first service flow and the identifier information of the second service flow. For example, it can be the flow description information of the first service flow and the flow description information of the second service flow, such as a service data flow template (SDF) template, thereby ensuring that the UPF determines the two associated service flows based on the SDF templates of the first service flow and the second service flow.

[0202] In one possible implementation, the UPF adds the above-mentioned association information to the GTP-U layer of the data packets contained in the first PDU Set and / or the second PDU Set, such as the GTP-U header. The information of the GTP-U layer is information that can be obtained by the access network device, so the access network device can determine that the first PDU Set is associated with the second PDU Set based on the association information added by the UPF to the first PDU Set and / or the second PDU Set. Exemplarily, the UPF adds the association information to the GTP-U header of the first PDU Set and / or the second PDU Set, which may refer to the UPF adding the association information to the GTP-U header of the data packets corresponding to the first PDU Set and / or the second PDU Set.

[0203] The embodiments of the present application do not limit the specific implementation manner in which the UPF adds association information to the first PDU Set and / or the second PDU Set based on the first indication information, the third association information, and the fourth association information. In one possible implementation manner, the UPF determines that the first service flow and the second service flow are associated based on the first indication information; the UPF determines that the first PDU Set and the second PDU Set are associated based on the third association information and the fourth association information; and the UPF adds association information to the associated first PDU Set and / or second PDU Set.

[0204] The embodiments of the present application do not limit the specific implementation method in which the UPF determines the association between the first PDU Set and the second PDU Set based on the third association information and the fourth association information.

[0205] A possible implementation method is that when the third association information and the fourth association information are the same, the difference between the third association information and the fourth association information is less than or equal to the threshold, the difference between the third association information and the fourth association information is within the threshold range, or the difference between the third association information and the fourth association information is equal to the offset value, the UPF determines that the first PDU Set of the first business flow and the second PDU Set of the second business flow are associated.

[0206] When the UPF receives the third indication information from the SMF, the UPF determines that the first PDU Set and the second PDU Set are associated based on the third indication information, the third association information, and the fourth association information. Exemplarily, when the third indication information is also used to instruct the UPF on a method for identifying associated PDU Sets, the UPF identifies that the first PDU Set and the second PDU Set are associated based on the third association information and the fourth association information in the method indicated by the third indication information. For example, when the third association information is the first RTP timestamp carried by the first PDU Set, the fourth association information is the second RTP timestamp carried by the second PDU Set, and the third indication information indicates that PDU Sets with the same RTP timestamp are associated, when the first RTP timestamp and the second RTP timestamp are the same, the UPF determines that the first PDU Set and the second PDU Set are associated.

[0207] The embodiments of the present application do not limit the specific implementation method of the UPF adding association information to the first PDU Set and / or the second PDU Set.

[0208] In one possible implementation, the UPF adds first association information to the first PDU Set and second association information to the second PDU Set, where the first association information and the second association information are the same. That is, the UPF adds the same association information to the associated first and second PDU Sets. For example, the first and second association information can be PDU Set SNs, timestamps, or other synchronization identifiers.

[0209] In another possible implementation, the UPF adds association information to the first PDU Set and / or the second PDU Set to indicate the offset value between the identification information of the associated PDU Set between the first service flow and the second service flow. The UPF adds association information to the first PDU Set but does not add association information to the second PDU Set. The association information includes the identifier of the second service flow and the offset value between the identification information of the associated PDU Set between the first service flow and the second service flow. Alternatively, the UPF adds association information to the second PDU Set but does not add association information to the first PDU Set. The association information includes the identifier of the first service flow and the offset value between the identification information of the associated PDU Set between the first service flow and the second service flow. Alternatively, the UPF adds first association information to the first PDU Set and second association information to the second PDU Set, the first association information including the identifier of the reference service flow and a first offset value, the first offset value being the offset value between the identification information of the associated PDU Set between the first service flow and the reference service flow, the second association information including the identifier of the reference service flow and the second offset value, the second offset value being the offset value between the identification information of the associated PDU Set between the second service flow and the reference service flow. Alternatively, the UPF adds first association information to the first PDU Set and second association information to the second PDU Set, the first association information including the identifier of the second service flow and the offset value between the identification information of the associated PDU Set between the first service flow and the second service flow, the second association information including the identifier of the first service flow and the offset value between the identification information of the associated PDU Set between the first service flow and the second service flow. Alternatively, the UPF adds first association information to the first PDU Set and second association information to the second PDU Set, where the first association information includes first identification information and the second association information includes first identification information, so that the access network device determines that the first PDU Set is associated with the second PDU Set based on the same first identification information carried in the associated first service flow and the second service flow, and performs synchronous transmission of the associated first PDU Set and second PDU Set.

[0210] For the above implementation, the UPF may further add first identification information to the first PDU Set and second identification information to the second PDU Set, wherein the first identification information is the same as the third association information, and the second identification information is the same as the fourth association information. In addition, when the UPF does not receive the offset value between the identification information of the associated PDU Sets between the first service flow and the second service flow from the SMF, the UPF may further determine the offset value between the identification information of the associated PDU Sets between the first service flow and the second service flow based on the third association information and the fourth association information.

[0211] When the UPF receives the fourth indication information from the SMF, and the fourth indication information indicates a method for marking the associated PDU Set, the UPF may add associated information to the first PDU Set and / or the second PDU Set based on the method indicated by the fourth indication information.

[0212] In step 208, the UPF sends the first PDU Set of the first service flow and the second PDU Set of the second service flow to the access network device. Correspondingly, the access network device receives the first PDU Set of the first service flow and the second PDU Set of the second service flow from the UPF.

[0213] The first PDU Set and / or the second PDU Set includes association information for determining that the first PDU Set and the second PDU Set are associated with each other.

[0214] In step 209 , the access network device synchronously transmits the first PDU Set and the second PDU Set according to the first indication information and the association information carried in the first PDU Set and / or the second PDU Set.

[0215] The synchronous transmission of the first PDU Set and the second PDU Set can be understood as: the difference in transmission delay between the first PDU Set and the second PDU Set is less than or equal to x ms, and x can be 0 or other values ​​that do not affect the service experience. Alternatively, it can also be understood as: the transmission of the first PDU Set and the second PDU Set is completed, that is, the upper limit of the delay from the first data of the first PDU Set and the second PDU Set arriving at the access network device side to the completion of the transmission of all data packets or the last data packet of the first PDU Set and the second PDU Set is x ms, that is, xms is the joint or total transmission delay budget of the first PDU Set and the second PDU Set, and x is a value that does not affect the service experience. Among them, x can be indicated to the access network device by the core network side (such as AF, PCF or SMF, etc.) through the second indication information, or it can be pre-configured in the access network device, or it can be determined by the access network device itself, without limitation.

[0216] In one possible implementation, when the access network device obtains the second indication information from the SMF, the access network device may synchronize the transmission of the first PDU Set and the second PDU Set based on the first indication information, the associated information carried in the first PDU Set and / or the second PDU Set, and the second indication information, to meet the synchronization requirement indicated by the second indication information. Optionally, the synchronization requirement indicated by the second indication information may also be configured on the RAN side.

[0217] The embodiments of the present application do not limit the implementation manner in which the access network device performs synchronous transmission of the first PDU Set and the second PDU Set based on the first indication information and the association information carried in the first PDU Set and / or the second PDU Set.

[0218] In one possible implementation method, the access network device determines that the first service flow and the second service flow are associated based on the first indication information; determines that the first PDU Set and the second PDU Set are associated based on the association information carried in the first PDU Set and / or the second PDU Set; and synchronously transmits the associated first PDU Set and second PDU Set.

[0219] The embodiments of the present application do not limit the specific implementation manner in which the access network device determines the association between the first PDU Set and the second PDU Set.

[0220] In one possible implementation, when the UPF adds the same association information to associated PDU Sets, the first PDU Set and / or the second PDU Set carries the association information, including: the first PDU Set carries the first association information, and the second PDU Set carries the second association information. When the first association information and the second association information are the same, the access network device determines that the first PDU Set and the second PDU Set are associated. For example, the first association information and the second association information can be PDU Set SNs, timestamps, or other synchronization identifiers.

[0221] In another possible implementation, the UPF adds an offset value between the identification information of the first PDU Set and / or the second PDU Set, indicating the association between the first service flow and the second service flow. The association information is the offset value, the first PDU Set carries the first identification information, and the second PDU Set carries the second identification information. When the difference between the first identification information and the second identification information is equal to the offset value indicated by the association information, the access network device determines that the first PDU Set and the second PDU Set are associated.

[0222] For the manner in which the first identification information, the second identification information, and the first PDU Set and / or the second PDU Set carry the offset value, refer to step 207 .

[0223] It should be noted that the UPF may send the offset value between the identification information of the associated PDU Set between the first service flow and the second service flow to the access network device through the user plane as described in steps 207 and 208, or may send the offset value between the identification information of the associated PDU Set between the first service flow and the second service flow determined by it to the access network device through signaling of the control plane, without limitation. In other words, the first PDU Set and / or the second PDU Set may not carry the offset value, and the access network device determines that the first PDU Set and the second PDU Set are associated based on the offset value, the first identification information, and the second identification information received from the control plane. At this time, the first identification information and the second identification information may also be referred to as the first association information and the second association information, respectively.

[0224] In method 200, the UPF can identify and add association information for the PDU Set associated in the first business flow and the second business flow. The access network device can determine the PDU Set associated in the first business flow and the second business flow based on the association information added by the UPF, and then synchronously transmit the associated PDU Set, thereby achieving synchronous transmission guarantee for multiple business flows.

[0225] The following, in conjunction with Figures 3 and 4, describes in detail the situation where multiple service flows requiring synchronous transmission assurance are transmitted through the same UPF. The flow description information, synchronization indication information #1, synchronization indication information #2, and synchronization indication information #3 of the multimodal service flow in Figures 3 and 4 can correspond to the first indication information above, the synchronization requirement information and synchronization transmission delay can correspond to the second indication information above, the association identification information #1, association identification information #2, and association identification information #3 can correspond to the third indication information above, and the association tag information #1 can correspond to the fourth indication information above.

[0226] FIG3 is a schematic flowchart of a communication method 300 provided in an embodiment of the present application.

[0227] In method 300, based on the synchronization assistance information of AF, the UPF can identify multiple service flows that need to be synchronously processed and the association relationship between the PDU Sets of multiple service flows, and send them to the access network device after marking the association relationship. The access network device will synchronously transmit the PDU Sets with the association relationship, thereby realizing the synchronous transmission guarantee of multimodal service flows.

[0228] Step 301: The AF sends an AF request message to the PCF. Correspondingly, the PCF receives the AF request message from the AF.

[0229] The AF request message includes synchronization assistance information, which is used for synchronous transmission of multiple service flows.

[0230] The synchronization assistance information may include flow description information for the multimodal service flow. The flow description information for the multimodal service flow is used to determine the multimodal service flow that requires synchronization processing. Exemplarily, the flow description information for the multimodal service flow may include description information such as the IP quintuple or IP triplet corresponding to each multimodal service flow in the multimodal service flow that requires synchronization processing.

[0231] Optionally, the synchronization assistance information may also include association identification information #1. Association identification information #1 is used by the 5GS (such as UPF or access network equipment) to determine the association relationship between PDU Sets between multimodal service flows. Exemplarily, association identification information #1 can be used to indicate the identification method of the association relationship between PDU Sets between multimodal service flows. For a specific description, please refer to the third indication information in step 201.

[0232] Optionally, the synchronization assistance information may also include synchronization requirement information. The synchronization requirement information is used to characterize the application layer's synchronization requirements for multimodal service flows. For example, the synchronization requirement information may be that the transmission delay difference of the PDU Set granularity of the associated PDU Sets between the multimodal service flows is less than or equal to x ms, or that the joint transmission delay budget between the associated PDU Sets between the multimodal service flows is x ms, that is, the transmission of the associated PDU Sets between the multimodal service flows is completed within x ms.

[0233] It should be noted that if the AF is in a trusted domain (for example, the AF is an AF deployed by an operator), the AF can interact directly with the PCF, that is, the AF sends an AF request message to the PCF by calling the PCF's service interface, such as the Npcf_PolicyAuthorization service interface. If the AF is in a non-trusted domain (for example, the AF is a third-party AF), the AF interacts with the PCF through the NEF, that is, the AF calls the NEF's service interface, such as the Nnef_AFSessionWithQoS service interface, and sends an AF request message to the NEF. Subsequently, the NEF calls the PCF's service interface, such as the Npcf_PolicyAuthorization service interface, and sends an AF request message to the PCF.

[0234] It should be noted that step 301 is optional.

[0235] Step 302: The PCF generates a PCC rule based on the synchronization assistance information in the AF request message. Optionally, the PCF may also generate the PCC rule based on a local policy.

[0236] Among them, the PCC rule may include synchronization indication information #1. Synchronization indication information #1 is used to determine the multimodal service flow that needs to be synchronized. Exemplarily, the PCC rule can be a PCC rule at the service flow granularity, and the PCC rule corresponding to each multimodal service flow that needs to be synchronized can include the same synchronization indication information #1. In other words, the multimodal service flows corresponding to the PCC rule carrying synchronization indication information #1 are associated and need to be synchronized. That is, the service flow corresponding to the PCC rule carrying synchronization indication information #1 is a multimodal service flow serving the same service, and these service flows need to be associated and synchronized at the PDU Set granularity. The embodiments of the present application do not limit the implementation method of synchronization indication information #1. For example, synchronization indication information #1 can be the IP quintuple or IP triplet corresponding to the multimodal service flows that need to be synchronized. For another example, synchronization indication information #1 can be multimodal service identification information or other identification information.

[0237] Optionally, the PCC rule may also include a synchronization requirement, specifically the synchronization requirement may be included in the PDU Set QoS parameter, wherein the PDU Set QoS parameter is a QoS parameter for PDU Set granularity. The synchronization requirement may include a synchronization transmission delay, and the synchronization transmission delay may be an upper limit on the transmission delay between associated PDU Sets between multimodal service flows, that is, a joint transmission delay budget between associated PDU Sets between multimodal service flows, or a transmission delay difference between associated PDU Sets. The synchronization transmission delay may also be described as: a delay requirement for joint transmission of PDU Sets between multimodal service flows, or an upper limit on the delay of PDU Set transmission across multimodal service flows, or an upper limit on the delay difference of associated PDU Set transmissions between multimodal service flows. The PDU Set QoS parameters may also include other conventional parameters, which will not be described in detail here. The PCC rule may include one or more groups of PDU Set QoS parameters. When the PCC rule does not include synchronous transmission delay, the access network device can autonomously determine the synchronous transmission delay between multimodal service flows. For example, the access network device can transmit associated PDU Sets strictly according to the same transmission delay. Exemplarily, the access network device ensures that the transmission delay difference between associated PDU Sets is 0.

[0238] Optionally, the PCC rule may also include association identification information #2. Association identification information #2 indicates the identification method for the association relationship between PDU Sets between multimodal service flows. For details, refer to the description of association identification information #1. For example, if there is only one default identification method, the PCC rule may not include association identification information #2.

[0239] Step 303: When the terminal device initiates the PDU session establishment or modification process, the terminal device sends a PDU session establishment request or a PDU session modification request to the AMF, and the AMF sends the PDU session establishment request or the PDU session modification request to the SMF to trigger the SMF to initiate the session management (SM) policy association establishment or modification process.

[0240] Step 303 is an optional step.

[0241] Step 304: The PCF sends the PCC rules to the SMF. Correspondingly, the SMF receives the PCC rules from the PCF.

[0242] The PCC rule can be a PCC rule at the service flow granularity. In this case, the PCF sends multiple PCC rules to the SMF, each corresponding to a plurality of multimodal service flows that need to be processed synchronously. For a description of the PCC rule, please refer to step 302.

[0243] One possible implementation method is that when the PDU session establishment or modification process is initiated by the terminal device, that is, when step 303 is executed before step 304, after receiving the PDU session establishment request or PDU session modification request, the SMF will actively initiate the SM policy association establishment or modification process and obtain the PCC rules from the PCF.

[0244] Another possible implementation is that the PCF initiates the session management policy association modification process and sends the PCC rules to the SMF, thereby triggering the PDU session modification process. In this case, step 303 may not be performed.

[0245] In step 305, the SMF provides the UPF with the N4 rules according to the received PCC rules through the N4 session establishment or modification process. Optionally, the SMF may also provide the UPF with the N4 rules according to the local policy.

[0246] Among them, the N4 rule may include synchronization indication information #2. Synchronization indication information #2 is used to determine the multimodal service flow that needs to be synchronized. The embodiments of the present application do not limit the implementation method of synchronization indication information #2. For example, synchronization indication information #2 can be the IP five-tuple or IP triplet information corresponding to the multimodal service flow that needs to be synchronized, or the SDF template information corresponding to the multimodal service flow. For another example, synchronization indication information #2 can be multimodal service identification information or other identification information. For another example, synchronization indication information #2 can be the QFI of the multimodal service flow that needs to be synchronized.

[0247] Synchronization Indication Information #1 and Synchronization Indication Information #2 can be the same or different. For example, Synchronization Indication Information #1 can be the IP quintuple or IP triplet corresponding to the multimodal service flows that require synchronization, and Synchronization Indication Information #2 can be the QFI of the multimodal service flows that require synchronization. For example, both Synchronization Indication Information #1 and Synchronization Indication Information #2 can be multimodal service identification information or other identification information.

[0248] It should be noted that when the multimodal service flow that needs to be processed synchronously is a service flow sent to multiple terminal devices, that is, when multiple service flows of multiple terminal devices need to be processed synchronously, the synchronization indication information #2 also includes information that uniquely identifies the terminal device, such as the identifier of the PDU session of the terminal device and / or the identifier of the terminal device.

[0249] Optionally, the N4 rule may also include association identification information #3. Association identification information #3 is used to indicate the identification method for the association relationship between PDU Sets between multimodal service flows. For a detailed description, refer to the description of association identification information #1. For example, when there is only one default identification method or when the identification method is pre-configured on the UPF side, the N4 rule may not include association identification information #3.

[0250] Optionally, the N4 rule may also include association tag information #1. Association tag information #1 is used to indicate the tagging method for associated PDU Sets between multimodal service flows. The tagging method may include at least one of the following: adding the same PDU Set SN to the associated PDU Sets, or adding the same synchronization tag to the associated PDU Sets. For example, when there is only one default tagging method, the N4 rule may not include association tag information #1. The synchronization tag may be a synchronization identification tag other than the PDU Set SN.

[0251] It should be noted that the associated identification information #3 and the associated tag information #1 can be one piece of information or two independent pieces of information.

[0252] Step 306: The SMF sends an N2 session management message to the access network device according to the received PCC rule. Optionally, the SMF may also send the N2 session management message to the access network device according to a local policy.

[0253] Among them, the N2 session management message is specifically the N2 session management message sent by SMF to RAN through AMF. For example, SMF calls Namf_Communication_N1N2MessageTransfer to send the information to the AMF side, and then AMF sends it to the RAN side through the N2 session request message.

[0254] The N2 session management message includes PDU Set QoS parameters and synchronization indication information #3.

[0255] The PDU Set QoS parameters are QoS parameters used for PDU Set granularity.

[0256] Synchronization Indication Information #3 is used to identify the multimodal service flow that requires synchronization processing. The embodiments of this application do not limit the implementation of Synchronization Indication Information #3. For example, Synchronization Indication Information #3 may be multimodal service identification information or other identification information. For another example, Synchronization Indication Information #3 may be the QFI of the multimodal service flow that requires synchronization processing.

[0257] It should be noted that when the multimodal service flow that needs to be processed synchronously is a service flow sent to multiple terminal devices, that is, when multiple service flows of multiple terminal devices need to be processed synchronously, the synchronization indication information #3 also includes information that uniquely identifies the terminal device, such as the identifier of the PDU session of the terminal device and / or the identification information of the terminal device.

[0258] Optionally, the PDU Set QoS parameters may also include a synchronous transmission delay, which may be an upper limit on the transmission delay between associated PDU Sets between multimodal service flows, or a joint transmission delay budget between associated PDU Sets, or a transmission delay difference between associated PDU Sets. The synchronous transmission delay may also be described as: a delay requirement for joint transmission of PDU Sets between multimodal service flows, or an upper limit on the delay for transmission of associated PDU Sets across multimodal service flows, or an upper limit on the delay difference for transmission of associated PDU Sets between multimodal service flows. When the PDU Set QoS parameters do not include a synchronous transmission delay, when the access network device autonomously determines that the synchronous transmission delay between multimodal service flows can be determined, for example, the access network device may transmit associated PDU Sets strictly according to the same transmission delay.

[0259] In step 307, each network element or device executes the remaining process of the PDU session establishment or modification process. The specific process can be referred to the existing technology, such as Section 4.3.2.1 of TS23.502, and will not be described in detail here.

[0260] Step 308: When the downlink data packet of the multimodal service arrives at the UPF, the UPF identifies the multimodal service flow that needs to be synchronously processed according to the N4 rule from the SMF.

[0261] Specifically, the UPF can identify the multimodal service flow that needs to be synchronized based on the synchronization indication information #2 in the N4 rule.

[0262] In step 309, the UPF performs PDU Set association identification between the multimodal service flows that need to be synchronized, determines the PDU Sets with an associated relationship, and marks the PDU Sets with an associated relationship.

[0263] In one possible implementation, when the N4 rule includes association identification information #3, the UPF can perform PDU Set association identification between multimodal service flows that need to be synchronized based on the association identification information #3 to determine the PDU Set with an associated relationship.

[0264] For example, when the association identification information #3 indicates RTP timestamp-based identification, the UPF determines that the PDU Sets with the same timestamp are associated based on the timestamp carried in the RTP header of the downlink data packet in each multimodal service flow.

[0265] For another example, when the association identification information #3 indicates identification based on the RTP timestamp difference, the UPF determines that the PDU Set is associated if the timestamp difference is within the threshold range based on the timestamp carried by the RTP header of the downlink data packet in each multimodal service flow. It should be noted that the threshold range here can be within K1, (0, K1), or (M1, N1), where 0 <M1<N1。

[0266] For another example, when the association identification information #3 indicates identification based on the PDU Set SN, the UPF determines that the PDU Sets with the same PDU Set SN are associated based on the PDU Set SN carried in the RTP extension header of the downlink data packet in each multimodal service flow.

[0267] For another example, when the association identification information #3 indicates identification based on the PDU Set SN offset value, the UPF determines that the PDU Sets whose PDU Set SN offset values ​​are within the threshold range are associated based on the PDU Set SN carried in the RTP extension header of the downlink data packet in each multimodal service flow. It should be noted that the threshold range here can be within K2, (0, K2), or (M2, N2), where 0 <M2<N2。

[0268] In another possible implementation, when the N4 rule does not include association identification information #3, the UPF can perform PDU Set association identification between multimodal service flows that require synchronization based on a default identification method to determine the associated PDU Sets. The default identification method can be the identification method mentioned above or other identification methods, without limitation.

[0269] Another possible implementation method is when the N4 rule does not include association identification information #3. Based on internal implementation, the UPF performs PDU Set association identification between multimodal service flows that need to be synchronized and determines the PDU Set with an associated relationship. The embodiments of the present application do not limit the specific method of the UPF internal implementation. It can be the identification method mentioned above or other identification methods.

[0270] In one possible implementation, when the N4 rule includes association marking information #1, the UPF may mark the PDU Set having an association relationship according to the association marking information #1.

[0271] For example, when the association tag information #1 indicates to add the same PDU Set SN for the associated PDU Set, the UPF adds the same PDU Set SN to the GTP-U header of the downlink data packet corresponding to the associated PDU Set, so that the access network device can determine the associated PDU Set based on the same PDU Set SN.

[0272] For another example, when the association mark information #1 indicates to add the same synchronization mark for the associated PDU Set, the UPF adds the same synchronization mark to the GTP-U header of the downlink data packet corresponding to the associated PDU Set, so that the access network device can determine the associated PDU Set based on the same synchronization mark.

[0273] In another possible implementation, when the N4 rule does not include association tag information #1, the UPF may tag the PDU Sets with the association relationship based on a default tagging method. The default tagging method may be the tagging method mentioned above or other tagging methods, without limitation.

[0274] Another possible implementation method is that when the N4 rule does not include the association tag information #1, the UPF can mark the PDU Set with the association relationship based on internal implementation. The embodiments of the present application do not limit the specific method of the UPF internal implementation, which can be the marking method mentioned above or other marking methods.

[0275] In addition, the UPF can also identify downlink data packets, determine and mark downlink data packets belonging to the same PDU Set.

[0276] In step 310, the UPF sends the marked downlink data packet to the access network device. Correspondingly, the access network device receives the downlink data packet from the UPF.

[0277] Step 311: The access network device determines the multimodal service flow that needs to be synchronized according to the synchronization indication information #3 from the SMF.

[0278] In step 312, the access network device synchronously transmits the PDU Sets carrying the same PDU Set SN or synchronization flag in the multimodal service flow.

[0279] One possible implementation method is that when the PUD set QoS parameter includes the synchronization transmission delay, the access network device synchronizes the transmission of the PDU Set carrying the same PDU Set SN or synchronization mark in the multimodal service flow based on the synchronization transmission delay in the PUD set QoS parameter.

[0280] Another possible implementation is when the PDU set QoS parameters do not include the synchronous transmission delay, and when the access network device can autonomously determine the synchronous transmission delay between multimodal service flows, for example, the access network device can transmit the associated PDU Set strictly according to the same transmission delay.

[0281] FIG4 is a schematic flowchart of a communication method 400 provided in an embodiment of the present application.

[0282] In method 400, the AF or UPF can determine the offset value between the PDU Set SNs corresponding to the PDU Sets with associated relationships between multiple service flows that need to be processed synchronously, and provide it to the access network device. The access network device then synchronizes the PDU Sets with associated relationships based on the received PDU Set SN offset value, thereby achieving synchronous transmission guarantee of multimodal service flows.

[0283] Steps 401 to 405 are the same as steps 301 to 305 , and reference may be made to steps 301 to 305 , which will not be described in detail here.

[0284] In step 406, the SMF sends an N2 session management message to the access network device according to the received PCC rule. Optionally, the SMF may also send the N2 session management message to the access network device according to a local policy.

[0285] Among them, the N2 session management message is specifically the N2 session management message sent by SMF to RAN through AMF. For example, SMF calls Namf_Communication_N1N2MessageTransfer to send the information to the AMF side, and then AMF sends it to the RAN side through the N2 session request message.

[0286] The N2 session management message includes PDU Set QoS parameters and synchronization indication information #3.

[0287] The PDU Set QoS parameters are QoS parameters used for PDU Set granularity.

[0288] Synchronization Indication Information #3 is used to identify the multimodal service flow that requires synchronization processing. The embodiments of this application do not limit the implementation of Synchronization Indication Information #3. For example, Synchronization Indication Information #3 may be multimodal service identification information or other identification information. For another example, Synchronization Indication Information #3 may be the QFI of the multimodal service flow that requires synchronization processing.

[0289] It should be noted that when the multimodal service flow that needs to be processed synchronously is a service flow sent to multiple terminal devices, that is, when multiple service flows of multiple terminal devices need to be processed synchronously, the synchronization indication information #3 also includes information that uniquely identifies the terminal device, such as the identifier of the PDU session of the terminal device and / or the identification information of the terminal device.

[0290] Optionally, the PDU Set QoS parameters may also include a synchronous transmission delay, which may be an upper limit on the transmission delay between associated PDU Sets between multimodal service flows, or a joint transmission delay budget between associated PDU Sets, or a transmission delay difference between associated PDU Sets. The synchronous transmission delay may also be described as: a delay requirement for joint transmission of PDU Sets between multimodal service flows, or an upper limit on the delay for transmission of associated PDU Sets across multimodal service flows, or an upper limit on the delay difference for transmission of associated PDU Sets between multimodal service flows. When the PDU Set QoS parameters do not include a synchronous transmission delay, when the access network device autonomously determines that the synchronous transmission delay between multimodal service flows can be determined, for example, the access network device may transmit associated PDU Sets strictly according to the same transmission delay.

[0291] Optionally, the N2 session management message may also include a PDU Set SN offset value. The PDU Set SN offset value here refers to the offset value between the PDU Set SNs corresponding to the associated PDU Sets between different service flows. For example, when the application server uses an RTP extension header carrying the PDU Set SN or other protocol headers carrying the PDU Set SN or synchronization identifier, the AF can determine the offset value between the PDU Set SNs corresponding to the associated PDU Sets between the multimodal service flows that need to be synchronized, and provide it to the access network device through the PCF and SMF.

[0292] The embodiments of the present application do not limit the setting method of the PDU Set SN offset value.

[0293] As an example, the PDU Set SN offset value of a service flow can be an offset value relative to the PDU Set SN corresponding to the PDU Set of a reference flow, where the reference flow can be one of the multimodal service flows that require synchronization. For example, the multimodal service flows that require synchronization include service flow #1, service flow #2, and service flow #3. Service flow #1 is used as the reference flow, and PDU Set A in service flow #1, PDU Set B in service flow #2, and PDU Set C in service flow #3 are associated. The PDU Set SN in the RTP header corresponding to PDU Set A is 10, the PDU Set SN in the RTP header corresponding to PDU Set B is 15, and the PDU Set SN in the RTP header corresponding to PDU Set C is 12. Therefore, the PDU Set SN offset value in the PDU Set QoS parameters of service flow #1 is 0, the PDU Set SN offset value in the PDU Set QoS parameters of service flow #2 is 5, and the PDU Set SN offset value in the PDU Set QoS parameters of service flow #3 is 2. Note that it is assumed here that the UPF will copy the PDU Set SN in the RTP header when adding the PDU Set SN. If there are packets in the QoS flow that do not carry a PDU Set SN, the UPF will update the PDU Set SN offset value accordingly when adding the PDU Set SN for the packet.

[0294] As another example, the PDU Set SN offset value of a certain service flow may include an offset value of the PDU Set SN of the service flow relative to the PDU Set of each other service flow that needs to be synchronized. For example, the multimodal service flows that need to be processed synchronously include service flow #1, service flow #2, and service flow #3. PDU Set A in service flow #1, PDU Set B in service flow #2, and PDU Set C in service flow #3 are associated. The PDU Set SN in the RTP header corresponding to PDU Set A is 10, the PDU Set SN in the RTP header corresponding to PDU Set B is 15, and the PDU Set SN in the RTP header corresponding to PDU Set C is 12. Then, the PDU Set QoS parameters of service flow #1 may include a PDU Set SN offset value relative to service flow #2 (i.e., 5) and a PDU Set SN offset value relative to service flow #3 (i.e., 2). The PDU Set QoS parameters of service flow #2 may include a PDU Set SN offset value relative to service flow #1 (i.e., 5) and a PDU Set SN offset value relative to service flow #3 (i.e., 3). The PDU Set QoS parameters of service flow #3 may include a PDU Set SN offset value relative to service flow #1 (i.e., 5). The SN offset value (i.e., 2) and the PDU Set SN offset value (i.e., 3) relative to service flow #2 are set. Note that this assumes that the UPF will copy the PDU Set SN in the RTP header when adding the PDU Set SN. If there are packets in this QoS flow that do not carry a PDU Set SN, the UPF will update the PDU Set SN offset value accordingly when adding the PDU Set SN to the packet.

[0295] In step 407, each network element or device executes the remaining process of the PDU session establishment or modification process. The specific process can be referred to the existing technology, such as Section 4.3.2.1 of TS23.502, and will not be described in detail here.

[0296] There are two ways to transmit downlink data packets of multimodal services, which are introduced below.

[0297] Method A: Steps 408 to 411

[0298] Step 408: When the downlink data packet of the multimodal service arrives at the UPF, the UPF identifies the multimodal service flow that needs to be synchronously processed according to the N4 rule from the SMF.

[0299] Specifically, the UPF can identify the multimodal service flow that needs to be synchronized based on the synchronization indication information #2 in the N4 rule.

[0300] In step 409, the UPF identifies PDU Set associations between the multimodal service flows that require synchronization, determines the associated PDU Sets, and identifies the PDU Set SN offsets corresponding to the associated PDU Sets. The PDU Set SN offset setting method can be found in step 406.

[0301] The UPF performs PDU Set association identification between the multimodal service flows that need to be synchronously processed. For the implementation method of determining the PDU Set with an associated relationship, reference can be made to step 309 and will not be described in detail.

[0302] In step 410, the UPF adds the PDU Set SN to the GTP-U header of the downlink data packet based on existing methods. The UPF may also add the PDU Set SN offset value to the GTP-U header of the downlink data packet so that the access network device can determine the associated PDU Set based on the PDU Set SN offset value. In other words, the UPF may send the PDU Set SN offset value to the access network device in the GTP-U header of the downlink data packet via the user plane. For example, if there is a data packet in the QoS flow that does not carry a PDU Set SN, the UPF will update the PDU Set SN offset value accordingly when adding the PDU Set SN to the data packet.

[0303] In addition, the UPF may also send the determined PDU Set SN offset value to the access network device through the control plane, ie, via the SMF, so that the access network device can determine the associated PDU Set according to the offset value of the PDU Set SN.

[0304] FIG4 takes the example of sending the PDU Set SN offset value to the access network device through the GTP-U header of the downlink data packet.

[0305] In step 411, the UPF sends a downlink data packet to the access network device. Accordingly, the access network device receives the downlink data packet from the UPF.

[0306] The GTP-U header of the downlink data packet includes the PDU Set SN offset value.

[0307] In mode A, the UPF determines the PDU Set SN offset value corresponding to the associated PDU Sets between the multimodal service flows that need to be synchronized, and provides it to the access network device.

[0308] Method B: Steps 412 to 414

[0309] Step 412: When the downlink data packet of the multimodal service arrives at the UPF, the UPF identifies the multimodal service flow that needs to be synchronized according to the N4 rule from the SMF.

[0310] Specifically, the UPF can identify the multimodal service flow that needs to be synchronized based on the synchronization indication information #2 in the N4 rule.

[0311] Step 413: Optionally, the UPF copies the PDU Set SN in the RTP header of the downlink data packet and adds it to the GTP-U header of the downlink data packet.

[0312] In step 414, the UPF sends a downlink data packet to the access network device. Accordingly, the access network device receives the downlink data packet from the UPF.

[0313] The GTP-U header of the downlink data packet includes the PDU Set SN in the RTP header.

[0314] Method B can be applied to the scenario where the application server uses the RTP extension header carrying the PDU Set SN. In this scenario, the AF can determine the offset value between the PDU Set SNs corresponding to the associated PDU Sets between the multimodal service flows that need to be synchronized, and provide it to the access network device through the PCF and SMF. For example, the UPF provides the PDU Set SN offset value to the access network device through steps 401 to 406.

[0315] In addition, the UPF can also identify downlink data packets, determine and mark downlink data packets belonging to the same PDU Set.

[0316] Steps 415 to 416 may be subsequently executed.

[0317] Step 415: The access network device determines the multimodal service flow that needs to be synchronized according to the synchronization indication information #3 from the SMF.

[0318] In step 416, the access network device performs PDU Set association identification between the multimodal service flows that need to be synchronized based on the PDU Set SN offset value from the UPF, determines the PDU Sets with the association relationship, and synchronizes the transmission of the PDU Sets with the association relationship.

[0319] The PDU Set SN offset value used by the access network device may be provided by the UPF or the AF.

[0320] Scenario 2: Multiple service flows that require synchronous transmission assurance are transmitted through multiple UPFs

[0321] FIG5 is a schematic flowchart of a communication method 500 provided in an embodiment of the present application.

[0322] Method 500 can be performed by access network equipment, UPF, SMF, PCF and / or AF. Unless otherwise specified, "access network equipment", "UPF", "SMF", "PCF" or "AF" may refer to the access network equipment, UPF, SMF, PCF or AF itself, or may refer to a device that can support the access network equipment, UPF, SMF, PCF or AF to implement its functions. For the sake of convenience of description, the access network equipment, UPF, SMF, PCF or AF will be used for description below.

[0323] Method 500 includes at least part of the following.

[0324] Optionally, in step 501, the AF determines synchronization assistance information.

[0325] The synchronization auxiliary information is used for synchronous transmission of the first service flow and the second service flow. The first service flow and the second service flow are transmitted through different UPFs.

[0326] The synchronization assistance information may include first indication information. The first indication information is used to indicate that the first service flow and the second service flow are associated. The first service flow and the second service flow are associated, that is, the first service flow and the second service flow need to be synchronized and transmitted.

[0327] Optionally, the synchronization assistance information may further include second indication information. The second indication information is used to indicate a synchronization requirement between the first service flow and the second service flow.

[0328] For descriptions of the service flow requiring synchronous transmission guarantee, the first indication information, and the second indication information, refer to step 201 .

[0329] The synchronization assistance information may also include fifth indication information. The fifth indication information is used to indicate the association information added by the UPF to the first service flow. The association information may be used to determine the associated PDU Set between the first service flow and the second service flow.

[0330] In one possible implementation, the fifth indication information includes a third timestamp corresponding to the first service flow and a third PDU Set SN corresponding to the third timestamp. For example, the third PDU Set SN corresponding to the third timestamp may be a PDU Set SN that the UPF needs to add to the PDU Set with the third timestamp.

[0331] In another possible implementation, the fifth indication information includes the offset value of the PDU Set SN corresponding to the first business flow, and the PDU Set SN offset value corresponding to the first business flow is the offset value of the PDU Set SN added by the UPF to the PDU Set of the first business flow relative to the PDU Set SN added by the AS to the PDU Set of the first business flow.

[0332] Optionally, the synchronization assistance information may further include period information. The period information is used to indicate the time interval between two adjacent PDU Sets of the first service flow.

[0333] Optionally, in step 502, the AF sends synchronization assistance information to the PCF, and correspondingly, the PCF receives the synchronization assistance information from the AF.

[0334] Step 503: The PCF sends first indication information and fifth indication information to the SMF according to the received synchronization assistance information. Correspondingly, the SMF receives the first indication information and fifth indication information from the PCF.

[0335] Optionally, when the synchronization assistance information further includes second indication information or period information, the PCF further sends the second indication information or period information to the SMF, and correspondingly, the SMF further receives the second indication information or period information from the PCF.

[0336] If the PCF does not receive the synchronization assistance information from the AF side, the synchronization assistance information may be a local configuration from the PCF side, that is, the PCF generates the first indication information, the second indication information, the fifth indication information or the periodic information by itself.

[0337] Step 504: The SMF sends fifth indication information to the UPF based on the information received from the PCF. Correspondingly, the UPF receives the fifth indication information from the SMF.

[0338] Optionally, when the SMF also receives the periodic information, the SMF also sends the periodic information to the UPF, and accordingly, the UPF also receives the periodic information from the SMF.

[0339] It should be noted that the fifth indication information or periodic information sent by SMF to UPF and the fifth indication information or periodic information received by SMF from PCF can be the same or different in form, without limitation.

[0340] Step 505: The SMF sends first indication information to the access network device. Correspondingly, the access network device receives the first indication information from the SMF.

[0341] Optionally, when the SMF also receives the second indication information, the SMF also sends the second indication information to the access network device, and accordingly, the access network device also receives the second indication information from the SMF.

[0342] It should be noted that the first indication information or second indication information sent by SMF to UPF can be the same as or different from the first indication information or second indication information received by SMF from PCF, without limitation.

[0343] It should be noted that the PCF, SMF, and UPF shown in Figure 5 correspond to the first service flow. The above description only describes the control plane signaling interaction for the first service flow. For the control plane signaling interaction for the second service flow, refer to steps 502 to 505 and will not be described in detail. The fifth indication information for the second service flow is used to instruct the UPF to add association information to the second service flow.

[0344] Step 506: The UPF receives the first PDU Set of the first service flow.

[0345] The first PDU Set carries the third associated information. Exemplarily, the third associated information is the first PDU Set SN or the first RTP timestamp carried by the first PDU Set.

[0346] Step 507: The UPF adds first association information to the first PDU Set according to the fifth indication information and the third association information.

[0347] In one possible implementation, the UPF adds the first association information to the GTP-U layer of the first PDU Set, such as in the GTP-U header. The GTP-U layer information is accessible to the access network device, so the access network device can determine the PDU Set associated with the first PDU Set based on the first association information added by the UPF to the first PDU Set.

[0348] The embodiments of the present application do not limit the implementation method of the UPF adding the first association information to the first PDU Set based on the fifth indication information and the third association information.

[0349] In one possible implementation, when the fifth indication information includes a third timestamp corresponding to the first service flow and a third PDU Set SN corresponding to the third timestamp, and the first PDU Set carries the first timestamp, the UPF adds the first PDU Set SN to the first PDU Set based on the third timestamp, the third PDU Set SN, and the first timestamp. When the UPF obtains the periodic information, the UPF adds the first PDU Set SN to the first PDU Set based on the third timestamp, the third PDU Set SN, the first timestamp, and the periodic information.

[0350] For example, the third timestamp is 10:00:00, the third PDU Set SN is 10, the periodic information indicates that the time interval between two adjacent PDU Sets of the first service flow is 2s, the first timestamp carried by the first PDU Set is 10:00:04, and the first PDU Set is the second PDU Set after the third timestamp. Therefore, the first PDU Set SN added by the UPF to the first PDU Set can be 12.

[0351] Another possible implementation method is that when the fifth indication information includes the offset value of the PDU Set SN corresponding to the first service flow and the first PDU Set carries the fourth PDU Set SN, the UPF adds the first PDU Set SN to the PDU Set based on the offset value in the fifth indication information and the fourth PDU Set SN, and the first PDU Set SN is offset relative to the fourth PDU Set SN by the offset value in the fifth indication information.

[0352] For example, the offset value in the fifth indication information is 5, the fourth PDU Set SN carried by the first PDU Set is 12, and the first PDU Set SN added by the UPF to the first PDU Set may be 17.

[0353] It should be noted that the above only describes the method in which the UPF adds the first association information to the first PDU Set of the first business flow. The method in which the UPF of the second business flow adds the second association information to the second PDU Set of the second business flow can refer to steps 506 to 507 and will not be described in detail.

[0354] In step 508, the UPF sends the first PDU Set of the first service flow to the access network device. Correspondingly, the access network device receives the first PDU Set of the first service flow from the UPF.

[0355] The first association information for determining the association between the first PDU Set and the second PDU Set is added to the first PDU Set.

[0356] Step 509: The access network device receives a second PDU Set from the UPF of the second service flow.

[0357] The second PDU Set includes second association information for determining the association between the first PDU Set and the second PDU Set.

[0358] In step 510, the access network device synchronously transmits the first PDU Set and the second PDU Set according to the first indication information, the first association information carried by the first PDU Set, and the second association information carried by the second PDU Set.

[0359] The synchronous transmission of the first PDU Set and the second PDU Set can be understood as: the difference in transmission delay between the first PDU Set and the second PDU Set is less than or equal to x ms, and x can be 0 or other values ​​that do not affect the service experience. Or it can also be understood as: the transmission of the first PDU Set and the second PDU Set is completed, that is, the upper limit of the delay from the first data of the first PDU Set and the second PDU Set arriving at the access network device side to the completion of the transmission of all data packets or the last data packet of the first PDU Set and the second PDU Set is x ms, that is, xms is the joint or total transmission delay budget of the first PDU Set and the second PDU Set, and x is a value that does not affect the service experience. Among them, x can be indicated to the access network device by the core network side (such as AF, PCF or SMF, etc.) through the second indication information, or it can be pre-configured in the access network device, or it can be determined by the access network device itself, without limitation.

[0360] In one possible implementation, when the access network device obtains the second indication information from the SMF, the access network device may synchronize the transmission of the first PDU Set and the second PDU Set based on the first indication information, the first association information carried by the first PDU Set, the second association information carried by the second PDU Set, and the second indication information, to meet the synchronization requirement indicated by the second indication information. Optionally, the synchronization requirement indicated by the second indication information may also be configured on the RAN side.

[0361] The embodiments of the present application do not limit the implementation manner in which the access network device performs synchronous transmission of the first PDU Set and the second PDU Set according to the first indication information, the first association information carried by the first PDU Set, and the second association information carried by the second PDU Set.

[0362] In one possible implementation method, the access network device determines that the first service flow and the second service flow are associated based on the first indication information; determines that the first PDU Set and the second PDU Set are associated based on the first association information carried by the first PDU Set and the second association information carried by the second PDU Set; and synchronously transmits the associated first PDU Set and the second PDU Set.

[0363] The embodiments of the present application do not limit the specific implementation manner in which the access network device determines that the first PDU Set and the second PDU Set are associated. In one possible implementation manner, when the first association information and the second association information are the same, the access network device determines that the first PDU Set and the second PDU Set are associated.

[0364] In method 500, the AF can indicate to the UPF the association information to be added for the service flow, so that the UPF can add the association information to the PDU Set based on the association information indicated by the AF. Based on this, the UPF corresponding to the first service flow and the UPF corresponding to the second service flow can ensure that the PDU Sets associated with the first service flow and the second service flow carry the same association information. The access network device can synchronously transmit the PDU Sets carrying the same association information, thereby ensuring the synchronous transmission of multiple service flows.

[0365] The method 500 is described in detail below with reference to FIG. 6 .

[0366] FIG6 is a schematic flowchart of a communication method 600 provided in an embodiment of the present application.

[0367] The associated mark information #A, associated mark information #B and associated mark information #C in Figure 6 can correspond to the fifth indication information above, the synchronization indication information #3 can correspond to the first indication information above, and the synchronization transmission delay can correspond to the second indication information above.

[0368] In method 600, the UPF needs to add a PDU Set SN or synchronization identifier to the downlink data packet according to specific rules, so as to ensure that the PDU Sets associated with multiple service flows that need to be transmitted synchronously carry the same PDU Set SN or synchronization identifier, so that the access network equipment can synchronously transmit the PDU Sets carrying the same PDU Set SN or synchronization identifier, thereby achieving synchronous transmission guarantee of multimodal service flows.

[0369] Step 601: The AF sends an AF request message to the PCF. Correspondingly, the PCF receives the AF request message from the AF.

[0370] The AF request message includes synchronization assistance information, which is used for synchronous transmission of multiple service flows.

[0371] Step 601 may refer to step 301. The difference from step 301 is that the synchronization auxiliary information in step 601 includes association mark information #A.

[0372] In one possible implementation, the association tag information #A may include an RTP timestamp and a PDU Set SN or synchronization tag corresponding to the RTP timestamp. In this implementation, upon receiving a downlink data packet carrying the RTP timestamp, the UPF may add the PDU Set SN or synchronization tag corresponding to the RTP timestamp in the GTP-U header of the downlink data packet.

[0373] In another possible implementation, the association tag information #A may include a PDU Set SN offset value. The PDU Set SN offset value may refer to the difference between the PDU Set SN carried in the RTP extension header of the downlink data packet and the PDU Set SN added to the GTP-U header of the downlink data packet. In this manner, upon receiving a downlink data packet carrying a PDU Set SN, the UPF may determine the PDU Set SN added to the GTP-U header of the downlink data packet based on the PDU Set SN carried in the RTP extension header and the PDU Set SN offset value.

[0374] Before sending the AF request message to the PCF, the AF may determine or coordinate the association between the RTP timestamp and the PDU Set SN or synchronization flag corresponding to the RTP timestamp, or determine the PDU Set SN offset value corresponding to each multimodal service flow in the multimodal service flow that needs to be synchronized.

[0375] Step 602: The PCF generates a PCC rule based on the synchronization assistance information in the AF request message. Optionally, the PCF may also generate the PCC rule based on a local policy.

[0376] Step 602 may refer to step 302. Unlike step 302, the PCC rule includes association tag information #B, which may include an RTP timestamp and the PDU Set SN or synchronization flag corresponding to the RTP timestamp, or a PDU Set SN offset value. For a description of association tag information #B, refer to association tag information #A.

[0377] Step 603 and step 604 may refer to step 303 and step 304 and will not be described in detail.

[0378] In step 605, the SMF provides the UPF with the N4 rules according to the received PCC rules through the N4 session establishment or modification process. Optionally, the SMF may also provide the UPF with the N4 rules according to the local policy.

[0379] The N4 rule may include association tag information #C. Association tag information #C may include the RTP timestamp and the PDU Set SN or synchronization flag corresponding to the RTP timestamp, or may include a PDU Set SN offset value. For a description of association tag information #C, refer to association tag information #A.

[0380] It should be noted that when a multimodal service flow that needs to be transmitted synchronously is transmitted through multiple UPFs (such as UPF#1 and UPF#2 in Figure 6), the AF can provide the N4 rules carrying the association tag information #C to the multiple UPFs respectively in the manner shown in steps 601 to 605. Among them, for the case where the association tag information #C includes the RTP timestamp and the PDU Set SN or synchronization tag corresponding to the RTP timestamp, the N4 rules of multiple service flows can carry the same association tag information #C. For the case where the association tag information #C includes the PDU Set SN offset value, the N4 rule of each service flow in the multiple service flows includes the PDU Set SN offset value corresponding to the service flow. In other words, the association tag information #C in the N4 rules of multiple service flows can be different.

[0381] Step 606 and step 607 may refer to step 306 and step 307 and will not be described in detail.

[0382] After multiple UPFs receive downlink data packets, each UPF can add a PDU Set SN or synchronization mark to the downlink data packet in accordance with steps 608 and 609, and send the downlink data packet with the added PDU Set SN or synchronization mark to the access network device. Steps 608 and 609 are specifically as follows.

[0383] Step 608: When the downlink data packet of the multimodal service arrives at the UPF, the UPF adds a PDU Set SN or synchronization marker to the downlink data packet according to the N4 rule from the SMF.

[0384] A possible implementation method is that when the N4 rule includes association tag information #C, and the association tag information #C includes the RTP timestamp and the PDU Set SN or synchronization tag corresponding to the RTP timestamp, the UPF determines the PDU Set SN or synchronization tag corresponding to the PDU Set to which the downlink data packet belongs based on the timestamp in the RTP header of the downlink data packet, the RTP timestamp in the association tag information #C, and the correspondence between the RTP timestamp in the association tag information #C and the PDU Set SN or synchronization tag, and adds the determined PDU Set SN or synchronization tag to the GTP-U header of the downlink data packet.

[0385] In another possible implementation, when the N4 rule includes association tag information #C, and the association tag information #C includes a PDU Set SN offset value, the UPF determines the PDU Set SN corresponding to the PDU Set to which the downlink data packet belongs based on the PDU Set SN in the RTP header of the downlink data packet and the PDU Set SN offset value in the association tag information #C, and adds the determined PDU Set SN to the GTP-U header of the downlink data packet. For example, if the PDU Set SN in the RTP header of the downlink data packet is 10 and the PDU Set SN offset value in the association tag information #C is 5, then the PDU Set SN corresponding to the PDU Set to which the downlink data packet belongs is 15.

[0386] Another possible implementation method is that when the N4 rule does not include the association tag information #C, the UPF adds a PDU Set SN or synchronization tag to the downlink data packet based on internal implementation. The embodiments of the present application do not limit the specific implementation method of the UPF internal implementation, which can be the method mentioned above or other methods.

[0387] In addition, the UPF can also identify downlink data packets, determine and mark downlink data packets belonging to the same PDU Set.

[0388] Step 609: The UPF sends a downlink data packet to the access network device. Correspondingly, the access network device receives the downlink data packet from the UPF.

[0389] Step 610: The access network device determines the multimodal service flow that needs to be synchronized according to the synchronization indication information #3 from the SMF.

[0390] In step 611, the access network device synchronously transmits the PDU Sets carrying the same PDU Set SN or synchronization flag in the multimodal service flow.

[0391] The methods shown in Figures 5 and 6 implement synchronous transmission of multiple service flows in Scenario 2 by indicating to the UPF the association information to be added to the service flows. In the present application, synchronous transmission of multiple service flows in Scenario 2 can also be implemented by having the access network device perform the identification of the associated PDU Sets, while the UPF does not perform the identification of the associated PDU Sets. This method is described below.

[0392] FIG7 is a schematic flowchart of a communication method 700 provided in an embodiment of the present application.

[0393] Method 500 can be performed by access network equipment, UPF, SMF, PCF and / or AF. Unless otherwise specified, "access network equipment", "UPF", "SMF", "PCF" or "AF" may refer to the access network equipment, UPF, SMF, PCF or AF itself, or may refer to a device that can support the access network equipment, UPF, SMF, PCF or AF to implement its functions. For the sake of convenience of description, the access network equipment, UPF, SMF, PCF or AF will be used for description below.

[0394] Method 700 includes at least part of the following.

[0395] Optionally, in step 701, the AF determines synchronization assistance information.

[0396] The synchronization auxiliary information is used for synchronous transmission of the first service flow and the second service flow. The first service flow and the second service flow are transmitted through different UPFs.

[0397] The synchronization assistance information may include first indication information. The first indication information is used to indicate that the first service flow and the second service flow are associated. The first service flow and the second service flow are associated, that is, the first service flow and the second service flow need to be synchronized and transmitted.

[0398] Optionally, the synchronization assistance information may further include second indication information. The second indication information is used to indicate a synchronization requirement between the first service flow and the second service flow.

[0399] For descriptions of the service flow requiring synchronous transmission guarantee, the first indication information, and the second indication information, refer to step 201 .

[0400] Optionally, the synchronization assistance information may further include sixth indication information. The sixth indication information is used to instruct the UPF to add the association information carried by the PDU Set to the GTP-U header.

[0401] Optionally, in step 702, the AF sends synchronization assistance information to the PCF, and correspondingly, the PCF receives the synchronization assistance information from the AF.

[0402] Step 703: The PCF sends first indication information to the SMF according to the received synchronization assistance information. Correspondingly, the SMF receives the first indication information from the PCF.

[0403] Optionally, when the synchronization assistance information also includes the second indication information or the sixth indication information, the PCF also sends the second indication information or the sixth indication information to the SMF, and accordingly, the SMF also receives the second indication information or the sixth indication information from the PCF.

[0404] Step 704: The SMF sends sixth indication information to the UPF based on the information received from the PCF. Correspondingly, the UPF receives the sixth indication information from the SMF.

[0405] Step 704 is an optional step.

[0406] It should be noted that the sixth indication information sent by SMF to UPF and the sixth indication information received by SMF from PCF can be the same or different in form, without limitation.

[0407] Step 705: The SMF sends first indication information to the access network device. Correspondingly, the access network device receives the first indication information from the SMF.

[0408] Optionally, when the SMF also receives the second indication information, the SMF also sends the second indication information to the access network device, and accordingly, the access network device also receives the second indication information from the SMF.

[0409] It should be noted that the first indication information or second indication information sent by SMF to UPF can be the same as or different from the first indication information or second indication information received by SMF from PCF, without limitation.

[0410] It should be noted that the PCF, SMF, and UPF shown in Figure 7 correspond to the first business flow. The above only describes the control plane signaling interaction of the first business flow. The control plane signaling interaction for the second business flow can refer to steps 702 to 705 and will not be described in detail.

[0411] Step 706: The UPF receives the first PDU Set of the first service flow.

[0412] The first PDU Set carries the first associated information. Exemplarily, the first associated information is the first PDU Set SN or the first RTP timestamp carried by the first PDU Set.

[0413] In step 707, the UPF adds the first association information to the GTP-U header of the first PDU Set.

[0414] When the UPF receives the sixth indication information, the UPF may add the first association information to the GTP-U header of the first PDU Set according to the sixth indication information.

[0415] It should be noted that the above only describes the method in which the UPF adds the first association information to the first PDU Set of the first business flow. The method in which the UPF of the second business flow adds the second association information to the second PDU Set of the second business flow can refer to steps 706 to 707 and will not be described in detail.

[0416] In step 708, the UPF sends the first PDU Set of the first service flow to the access network device. Correspondingly, the access network device receives the first PDU Set of the first service flow from the UPF.

[0417] The first association information for determining the association between the first PDU Set and the second PDU Set is added to the first PDU Set.

[0418] Step 709: The access network device receives a second PDU Set from the UPF of the second service flow.

[0419] The second PDU Set includes second association information for determining the association between the first PDU Set and the second PDU Set.

[0420] In step 710, the access network device synchronously transmits the first PDU Set and the second PDU Set according to the first indication information, the first association information carried by the first PDU Set, and the second association information carried by the second PDU Set.

[0421] One possible implementation method is that when the access network device obtains the second indication information from the SMF, the access network device can synchronously transmit the first PDU Set and the second PDU Set to meet the synchronization requirements indicated by the second indication information based on the first indication information, the first association information carried by the first PDU Set, the second association information carried by the second PDU Set, and the second indication information.

[0422] The embodiments of the present application do not limit the implementation manner in which the access network device performs synchronous transmission of the first PDU Set and the second PDU Set according to the first indication information, the first association information carried by the first PDU Set, and the second association information carried by the second PDU Set.

[0423] In one possible implementation method, the access network device determines that the first service flow and the second service flow are associated based on the first indication information; determines that the first PDU Set and the second PDU Set are associated based on the first association information carried by the first PDU Set and the second association information carried by the second PDU Set; and synchronously transmits the associated first PDU Set and the second PDU Set.

[0424] The embodiments of the present application do not limit the specific implementation method of the access network device determining the association between the first PDU Set and the second PDU Set. The specific implementation method can refer to the method in which the UPF determines the association between the first PDU Set and the second PDU Set based on the third association information and the fourth association information in step 207, wherein the various information required by the access network device can be obtained from the SMF.

[0425] In method 700, the access network device can perform identification of the associated PDU Set, and the UPF does not perform identification of the associated PDU Set. The access network device can synchronously transmit the associated PDU Set, thereby achieving synchronous transmission guarantee of multiple service flows.

[0426] The method 700 is described in detail below with reference to FIG. 8 .

[0427] FIG8 is a schematic flowchart of a communication method 800 provided in an embodiment of the present application.

[0428] The association mark information #D in FIG8 may correspond to the sixth indication information mentioned above, the synchronization indication information #3 may correspond to the first indication information mentioned above, and the synchronization transmission delay may correspond to the second indication information mentioned above.

[0429] In method 800, based on the synchronization assistance information of the AF, the access network device can identify multiple service flows that need to be synchronously processed and the association relationship between the PDU Sets of multiple service flows, and synchronously transmit the PDU Sets with the association relationship, thereby achieving synchronous transmission guarantee of multimodal service flows.

[0430] Steps 801 to 804 are the same as steps 301 to 304 , and reference may be made to steps 301 to 304 , which will not be described in detail here.

[0431] In step 805, the SMF provides the UPF with the N4 rules according to the received PCC rules through the N4 session establishment or modification process. Optionally, the SMF may also provide the UPF with the N4 rules according to the local policy.

[0432] Optionally, the N4 rule may include association tag information #D. Association tag information #D is used to instruct the UPF to add the timestamp or PDU Set SN in the RTP header of the downlink data packet to the GTP-U header of the downlink data packet. For example, when only one default tagging method is used, the N4 rule may not include association tag information #D.

[0433] It should be noted that when a multimodal service flow that needs to be transmitted synchronously is transmitted through multiple UPFs (such as UPF#1 and UPF#2 in Figure 8), the AF can provide the N4 rule carrying the association tag information #D to the multiple UPFs respectively in the manner shown in steps 801 to 805.

[0434] Step 806: The SMF sends an N2 session management message to the access network device according to the received PCC rule. Optionally, the SMF may also send the N2 session management message to the access network device according to a local policy.

[0435] The N2 session management message includes the PDU Set QoS parameter and synchronization indication information #3. For details about the PDU Set QoS parameter and synchronization indication information #3, refer to step 306.

[0436] Optionally, the N2 session management message may further include association identification information #3. Association identification information #3 is used to indicate the identification method for the association relationship between PDU Sets between multimodal service flows. For a detailed description, refer to the description of association identification information #1 in step 301. Exemplarily, when only one default identification method is used, the N2 session management message may not include association identification information #3.

[0437] In step 807, each network element or device executes the remaining process of the PDU session establishment or modification process. The specific process can be referred to the existing technology, such as Section 4.3.2.1 of TS23.502, and will not be described in detail here.

[0438] After multiple UPFs receive the downlink data packet, each UPF may process the downlink data packet according to step 808 and step 809. Step 808 and step 809 are specifically as follows.

[0439] In step 808, when the downlink data packet of the multimodal service reaches the UPF, the UPF adds the timestamp or PDU Set SN in the PTR header of the downlink data packet to the GTP-U header of the downlink data packet according to the N4 rule from the SMF.

[0440] A possible implementation method is that when the N4 rule includes the association mark information #D, the UPF can add the timestamp in the PTR header of the downlink data packet to the GTP-U header of the downlink data packet according to the association mark information #D, or add the PDU Set SN in the PTR header of the downlink data packet to the GTP-U header of the downlink data packet.

[0441] Another possible implementation method is that when the N4 rule does not include the association tag information #D, the UPF can add the timestamp in the PTR header of the downlink data packet to the GTP-U header of the downlink data packet based on the default method or based on internal implementation, or add the PDU Set SN in the PTR header of the downlink data packet to the GTP-U header of the downlink data packet.

[0442] In addition, the UPF can also identify downlink data packets, determine and mark downlink data packets belonging to the same PDU Set.

[0443] Step 809: The UPF sends a downlink data packet to the access network device. Correspondingly, the access network device receives the downlink data packet from the UPF.

[0444] Step 810: The access network device determines the multimodal service flow that needs to be synchronized based on the synchronization indication information #3 from the SMF.

[0445] In step 811, the access network device performs PDU Set association identification between multimodal service flows that need to be synchronously processed, determines PDU Sets with an associated relationship, and synchronously transmits the PDU Sets with the associated relationship.

[0446] The way in which access network equipment associates and identifies PDU Sets between multimodal service flows that need to be processed synchronously can refer to the way in which UPF associates and identifies PDU Sets between multimodal service flows that need to be processed synchronously. The difference is that the access network equipment is based on the timestamp or PSU set SN in the GTP-U header of the downlink data packet.

[0447] The manner in which the access network device synchronously transmits the associated PDU Sets may refer to step 312 and will not be described in detail.

[0448] In addition, the methods shown in FIG. 7 and FIG. 8 are also applicable to scenario 1.

[0449] The embodiment of the present application also provides a solution for ensuring the synchronous transmission of multiple service flows at the application layer. This solution is described below.

[0450] FIG9 is a schematic flowchart of a communication method 900 provided in an embodiment of the present application.

[0451] Method 900 can be performed by an access network device, UPF, AF, AS and / or an application service provider (ASP). Unless otherwise specified, "access network device", "UPF", "AF", "AS" or "ASP" may refer to the access network device, UPF, AF, AS or ASP itself, or may refer to a device that can support the access network device, UPF, AF, AS or ASP to perform its functions. For the sake of convenience, the following text will uniformly use access network device, UPF, AF, AS or ASP for description.

[0452] Exemplarily, the AF may be a real-time communication (RTC) AF.

[0453] It should be noted that the AF, AS and ASP in FIG9 can be independent network elements or devices, or can be functional units obtained by logical division on a communication device, without limitation.

[0454] Method 900 includes at least part of the following.

[0455] Step 901: The ASP determines and sends first configuration information to the AF. Correspondingly, the AF receives the first configuration information from the ASP.

[0456] Among them, the first configuration information is used to indicate the synchronous transmission of the first business flow and the second business flow of the service, or to instruct the AF to configure the application server to ensure the synchronous transmission of the first business flow and the second business flow, that is, to configure the application server to perform corresponding marking processing on the associated PDU Set of the first business flow and the second business flow.

[0457] Step 902: The AF sends second configuration information to the AS based on the first configuration information. Correspondingly, the AS receives the second configuration information from the AF.

[0458] The second configuration information is used to indicate that the same association information is added to the PDU Set associated between the first service flow and the second service flow.

[0459] Optionally, the second configuration information is further used to indicate a synchronization type. The synchronization type is single-user synchronization or multi-user synchronization. Single-user synchronization indicates that the first service flow and the second service flow are service flows of the same user. Multi-user synchronization indicates that the first service flow and the second service flow are service flows of different users.

[0460] Step 903: The AF sends first indication information to the access network device. Correspondingly, the access network device receives the first indication information from the AF.

[0461] The first indication information is used to indicate that the first service flow is associated with the second service flow.

[0462] The implementation of step 903 may refer to steps 701 , 702 , 703 and 705 , which will not be described in detail here.

[0463] Step 904: The AF sends sixth indication information to the UPF. Accordingly, the UPF receives the sixth indication information from the AF.

[0464] Among them, the sixth indication information is used to instruct the UPF to add the association information carried by the PDU Set to the GTP-U header.

[0465] Step 904 is an optional step. The implementation of step 904 can refer to steps 701, 702, 703 and 704, and will not be described in detail here.

[0466] Step 905: The AS adds the same association information to the first PDU Set of the first service flow and the second PDU Set of the second service flow according to the second configuration information.

[0467] The first PDU Set and the second PDU Set are associated.

[0468] Specifically, the AS adds first association information to the first PDU Set and adds second association information to the second PDU Set, and the first association information and the second association information are the same.

[0469] Exemplarily, the first associated information and the second associated information are PDU Set SN or other synchronization markers.

[0470] Step 906: The AS sends the first PDU Set of the first service flow and the second PDU Set of the second service flow to the UPF. Correspondingly, the UPF receives the first PDU Set of the first service flow and the second PDU Set of the second service flow from the AS.

[0471] The first PDU Set and the second PDU Set carry the same association information.

[0472] In step 907 , the UPF adds the first association information in the first PDU Set to the GTP-U header of the first PDU Set, and adds the second association information in the second PDU Set to the GTP-U header of the second PDU Set.

[0473] When the UPF receives the sixth indication, it adds the first association information in the first PDU Set to the GTP-U header of the first PDU Set and the second association information in the second PDU Set to the GTP-U header of the second PDU Set based on the sixth indication. Note that at this point, the UPF must strictly copy the PDU Set SN in the RTP extension header of the first PDU Set to the GTP-U layer of the corresponding data packet of the first PDU Set.

[0474] Step 908: The UPF sends the first PDU Set of the first service flow and the second PDU Set of the second service flow to the access network device. Correspondingly, the access network device receives the first PDU Set of the first service flow and the second PDU Set of the second service flow from the UPF.

[0475] In step 909 , the access network device synchronously transmits the first PDU Set and the second PDU Set according to the first indication information, the first association information carried by the first PDU Set, and the second association information carried by the second PDU Set.

[0476] Step 909 may refer to step 510 and will not be described in detail here.

[0477] 10 , a solution for ensuring synchronous transmission of multimodal service flows at the application layer will be described in detail.

[0478] FIG10 is a schematic flowchart of a communication method 1000 provided in an embodiment of the present application.

[0479] Configuration information #1 and configuration information #2 in FIG10 may correspond to the first configuration information and the second configuration information described above.

[0480] In method 1000, through application layer interaction, it is ensured that the RTP headers corresponding to the PDU Sets with associated relationships between the service flows that need to be transmitted synchronously carry the same PDU Set SN or synchronization mark. The UPF directly adds the PDU Set SN or synchronization mark in the PTR header of the downlink data packet to the GTP-U header of the downlink data packet, so that the access network device can synchronously transmit the PDU Sets with associated relationships, thereby realizing synchronous transmission guarantee of multimodal service flows.

[0481] Step 1001: ASP sends configuration information #1 to AF. Correspondingly, AF receives configuration information #1 from ASP.

[0482] Configuration information #1 is used to configure or create service #1.

[0483] The configuration information #1 of the embodiment of the present application may include indication information #1, which is used to indicate that synchronous transmission guarantee is performed for multiple service flows serving service #1. Optionally, indication information #1 can also be used to indicate that multiple service flows belong to the same terminal device or to indicate that multiple service flows belong to multiple terminal devices. In other words, indication information #1 is used to indicate that synchronous transmission guarantee is performed for multiple service flows belonging to the same terminal device of service #1 or to indicate that synchronous transmission guarantee is performed for multiple service flows belonging to multiple terminal devices of service #1. Optionally, the indication information #1 is also used to indicate that when identifying and marking the PDU Set in the service flow, marking is performed according to the PDU Set SN carried in the downlink data packet.

[0484] In one possible implementation, the ASP carries the above configuration information #1 in a message for creating a provisioning session.

[0485] Step 1002: The AF sends configuration information #2 to the AS based on configuration information #1. Correspondingly, the AS receives configuration information #2 from the AF.

[0486] Among them, configuration information #2 includes indication information #2, and indication information #2 is used to indicate that when adding PDU Set SN to PDU Sets in multiple service flows serving service #1, the same PDU Set SN or synchronization mark is added to PDU Sets that have an associated relationship between multiple service flows.

[0487] Optionally, configuration information #2 includes a synchronization type, which can be single-user synchronization or multi-user synchronization. Single-user synchronization indicates that multiple service flows of the same user need to be synchronized and guaranteed. Multi-user synchronization indicates that multiple service flows between multiple users need to be synchronized and guaranteed.

[0488] Step 1003: The AF sends a response message to the ASP. Correspondingly, the ASP receives a response message from the AF.

[0489] The response message is used to confirm the creation of service #1.

[0490] In a possible implementation, the response message is a message used to confirm the creation of a provisioning session.

[0491] The configuration process of ASP service #1 is completed through steps 1001 to 1003.

[0492] Step 1004: The terminal device establishes a connection with the AS.

[0493] Specifically, an application (App) in the terminal device is started, and the client establishes a connection with the AS, such as a WebRTC connection. Specifically, the RTC media session handler (MSH) in the terminal device establishes a connection with the AS.

[0494] Step 1005: The AS adds the same PDU Set SN or synchronization flag to the PDU Sets associated with multiple service flows serving service #1 according to the configuration information #2 from the AF.

[0495] Specifically, the AS adds the same PDU Set SN or synchronization flag to the PDU Sets associated with multiple service flows serving service #1 based on indication information #2 in configuration information #2. Optionally, when configuration information #2 includes a synchronization type, the AS adds the same PDU Set SN or synchronization flag to the PDU Sets associated with multiple service flows serving service #1 based on indication information #2 and the synchronization type.

[0496] Adding the same PDU Set SN or synchronization marker to the PDU Sets associated with multiple service flows serving service #1 based on the AF's configuration information is only one implementation method for adding the same PDU Set SN or synchronization marker to the PDU Sets associated with multiple service flows serving service #1. In other implementations, the AF may also add the same PDU Set SN or synchronization marker to the PDU Sets associated with multiple service flows serving service #1 based on local configuration or negotiation with the terminal device.

[0497] Step 1006: The AF provides synchronization assistance information to the core network.

[0498] The implementation of step 1006 can refer to steps 301 to 305, except that the synchronization assistance information may not include association identification information #1, the PCC rule generated by the PCF may not include association identification information #2, and the SMF does not need to provide synchronization indication information #2, association identification information #3, and association marking information #1 to the UPF. Additionally, the synchronization assistance information also includes indication information for marking the PDU Sets in the service flow according to the PDU Set SN carried in the downlink data packet.

[0499] Optionally, the AF may provide indication information #3 to the UPF through the PCF and SMF, where the indication information #3 is used to instruct the UPF to add the PDU Set SN or synchronization flag in the RTP header of the downlink data packet to the GTP-U header of the downlink data packet.

[0500] In step 1007 , the core network provides synchronization indication information # 3 and an optional synchronization transmission delay to the access network device. Step 1007 may refer to step 306 .

[0501] Step 1008: When the downlink data packet of the multimodal service reaches the UPF, the UPF adds the PDU Set SN or synchronization flag in the PTR header of the downlink data packet to the GTP-U header of the downlink data packet.

[0502] Step 1009: UPF sends a downlink data packet to the access network device. Correspondingly, the access network device receives the downlink data packet from UPF.

[0503] Step 1010: The access network device determines the multimodal service flow that needs to be synchronized based on the synchronization indication information #3 from the SMF.

[0504] In step 1011, the access network device transmits synchronously the PDU Sets carrying the same PDU Set SN or the same synchronization flag in the multimodal service flow that needs to be processed synchronously.

[0505] The above describes in detail the method embodiment provided by the present application in conjunction with Figures 2 to 10 , and the following describes the device embodiment of the present application in conjunction with Figures 11 to 13 .

[0506] It is understood that, in order to implement the functions in the above embodiments, the apparatuses in Figures 11 to 13 include hardware structures and / or software modules corresponding to the functions. Those skilled in the art should readily appreciate that, in conjunction with the various exemplary units and method steps described in the embodiments disclosed herein, the present application can be implemented in the form of hardware or a combination of hardware and computer software.

[0507] Figures 11 and 12 are schematic diagrams of possible apparatuses provided in embodiments of the present application. These apparatuses can be used to implement the functions of the access network device, user plane function network element, application function network element, application service provider, or application server in the above method embodiments, thereby also achieving the beneficial effects of the above method embodiments.

[0508] As shown in FIG. 11 , the device 10 includes a transceiver unit 11 and a processing unit 12 .

[0509] When the device 10 is used to implement the functions of the access network device, user plane function network element, application function network element, application service provider or application server in the above-mentioned method embodiments, the transceiver unit 11 is used to execute the transceiver steps of the access network device, user plane function network element, application function network element, application service provider or application server, and the processing unit 12 is used to execute the processing steps of the access network device, user plane function network element, application function network element, application service provider or application server.

[0510] For a more detailed description of the transceiver unit 11 and the processing unit 12 , please refer to the relevant description in the above method embodiment, which will not be described again here.

[0511] As shown in FIG12 , apparatus 20 includes a processing circuit 21. Processing circuit 21 is coupled to a memory 23, which is configured to store instructions. When apparatus 20 is used to implement the method described above, processing circuit 21 is configured to execute the instructions in memory 23 to implement the functions of processing unit 12 described above.

[0512] Optionally, the device 20 further includes a memory 23 .

[0513] Optionally, the apparatus 20 further includes a transceiver circuit 22. The transceiver circuit can be referred to as a communication interface. The processing circuit 21 and the transceiver circuit 22 are coupled to each other. It will be appreciated that the transceiver circuit 22 can be a transceiver or an input / output interface. When the apparatus 20 is used to implement the method described above, the processing circuit 21 is used to execute instructions to implement the functions of the processing unit 12, and the transceiver circuit 22 is used to implement the functions of the transceiver unit 11.

[0514] Optionally, the apparatus 20 may be an access network device, a user plane function network element, an application function network element, an application service provider or an application server, and accordingly, the transceiver circuit may be a transceiver.

[0515] Optionally, the device 20 may be a chip applied to an access network device, a user plane function network element, an application function network element, an application service provider or an application server, and accordingly, the transceiver circuit may be an input / output interface.

[0516] Exemplarily, when the device 20 is a chip applied to an access network device, a user plane function network element, an application function network element, an application service provider, or an application server, the chip implements the functions of the access network device, the user plane function network element, the application function network element, the application service provider, or the application server in the above method embodiment. The chip receives information from other modules (such as a radio frequency module or antenna) in the access network device, the user plane function network element, the application function network element, the application service provider, or the application server, and the information is sent by other devices to the access network device, the user plane function network element, the application function network element, the application service provider, or the application server; or the chip sends information to other modules (such as a radio frequency module or antenna) in the access network device, the user plane function network element, the application function network element, the application service provider, or the application server, and the information is sent by the access network device, the user plane function network element, the application function network element, the application service provider, or the application server to other devices.

[0517] 13 is a schematic diagram of a chip system 30 provided in an embodiment of the present application. The chip system 30 (or also referred to as a processing system) includes a logic circuit 31 and an input / output interface 32.

[0518] The logic circuit 31 may be a processing circuit in the chip system 30. The logic circuit 31 may be coupled to a storage unit and call instructions in the storage unit so that the chip system 30 can implement the methods and functions of the various embodiments of the present application. The input / output interface 32 may be an input / output circuit in the chip system 30, outputting information processed by the chip system 30 or inputting data or signaling information to be processed into the chip system 30 for processing.

[0519] As a solution, the chip system 30 is used to implement the operations performed by the access network device, user plane function network element, application function network element, application service provider or application server in the above various method embodiments.

[0520] For example, the logic circuit 31 is used to implement the processing-related operations performed by the access network device, user plane function network element, application function network element, application service provider or application server in the above method embodiment; the input / output interface 32 is used to implement the sending and / or receiving-related operations performed by the access network device, user plane function network element, application function network element, application service provider or application server in the above method embodiment.

[0521] The present application also provides a communication device, comprising a processing circuit coupled to a memory, the memory being used to store computer programs or instructions and / or data, and the processing circuit being used to execute the computer programs or instructions stored in the memory, or to read data stored in the memory, to perform the methods described in the above method embodiments. Optionally, there are one or more processing circuits. Optionally, the communication device includes a memory. Optionally, there are one or more memories. Optionally, the memory is integrated with the processing circuit or provided separately.

[0522] The present application also provides a chip, including a processing circuit coupled to a memory, the memory being configured to store computer programs or instructions, and the processing circuit being configured to execute the computer programs or instructions stored in the memory to implement the methods performed by an access network device, a user plane function network element, an application function network element, an application service provider, or an application server in each of the above-described method embodiments. The memory may be located within the chip or independently of the chip, and may be located externally from the chip, without limitation herein.

[0523] The present application also provides a computer-readable storage medium on which are stored computer instructions for implementing the methods executed by the access network device, user plane function network element, application function network element, application service provider or application server in the above-mentioned method embodiments.

[0524] The present application also provides a computer program product comprising instructions, which, when executed by a computer, implement the methods performed by the access network device, user plane function network element, application function network element, application service provider or application server in the above-mentioned method embodiments.

[0525] The present application also provides a communication system, which includes at least one of the access network device, user plane function network element, application function network element, application service provider or application server in the above embodiments.

[0526] The explanation of the relevant contents and beneficial effects of any of the above-mentioned devices can be referred to the corresponding method embodiments provided above, which will not be repeated here.

[0527] It is understood that the processing circuit in the embodiments of the present application can be a processor or a circuit in a processor for performing processing operations. The processor can be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field programmable gate arrays (FPGA), or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. The general-purpose processor can be a microprocessor or any conventional processor.

[0528] The method steps in the embodiments of the present application can be implemented by hardware or by a processor executing software instructions. The software instructions can be composed of corresponding software modules, which can be stored in random access memory, flash memory, read-only memory, programmable read-only memory, erasable programmable read-only memory, electrically erasable programmable read-only memory, registers, hard disk, removable hard disk, compact disc read-only memory (CD-ROM), or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor so that the processor can read information from the storage medium and write information to the storage medium. Of course, the storage medium can also be an integral part of the processor. The processor and storage medium can be located in an ASIC. In addition, the ASIC can be located in an access network device, a user plane function network element, an application function network element, an application service provider, or an application server. Of course, the processor and storage medium can also exist as discrete components in an access network device, a user plane function network element, an application function network element, an application service provider, or an application server.

[0529] In the above embodiments, all or part of the embodiments may be implemented using software, hardware, firmware, or any combination thereof. When implemented using software, all or part of the embodiments may be implemented in the form of a computer program product. The computer program product includes one or more computer programs or instructions. When the computer program or instructions are loaded and executed on a computer, the processes or functions described in the embodiments of the present application are performed in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, a network device, a user device, or other programmable device. The computer program or instructions may be stored in a computer-readable storage medium or transferred from one computer-readable storage medium to another. For example, the computer program or instructions may be transferred from one website, computer, server, or data center to another website, computer, server, or data center via wired or wireless means. The computer-readable storage medium may be any available medium that can be accessed by a computer or a data storage device such as a server or data center that integrates one or more available media. The available medium may be a magnetic medium, such as a floppy disk, hard disk, or magnetic tape; an optical medium, such as a digital video disk; or a semiconductor medium, such as a solid-state drive.

[0530] In the various embodiments of the present application, unless otherwise specified or there is a logical conflict, the terms and / or descriptions between different embodiments are consistent and can be referenced by each other. The technical features in different embodiments can be combined to form new embodiments according to their inherent logical relationships.

[0531] Unless otherwise indicated, all technical and scientific terms used in the embodiments of the present application have the same meaning as those generally understood by those skilled in the art of the technical field of the application. The terms used in this application are only for the purpose of describing specific embodiments and are not intended to limit the scope of the application. It should be understood that the above are for illustration, and the examples above are only for helping those skilled in the art to understand the embodiments of the present application, rather than limiting the application embodiments to the specific numerical values ​​or specific scenarios illustrated. Those skilled in the art can obviously carry out various equivalent modifications or changes based on the examples given above, and such modifications and changes also fall within the scope of the embodiments of the present application.

Claims

1. A communication method, characterized in that: The method comprises: The access network device obtains first indication information, where the first indication information is used to indicate that the first service flow and the second service flow are associated; The access network device receives, by the first protocol data unit set PDU Set of the first service flow and the second PDU Set of the second service flow, where the first PDU Set and / or the second PDU Set carry association information, and the association information is used by the access network device to determine that the first PDU Set and the second PDU Set are associated; The access network device synchronously transmits the first PDU Set and the second PDU Set according to the first indication information and the association information.

2. The method according to claim 1, characterized in that The method further includes: the access network device acquiring second indication information, where the second indication information is used to indicate a synchronization requirement between the first service flow and the second service flow; The access network device synchronously transmits the first PDU Set and the second PDU Set according to the first indication information and the associated information, including: the access network device synchronously transmits the first PDU Set and the second PDU Set according to the first indication information, the associated information and the second indication information.

3. The method according to claim 2, characterized in that The synchronization requirement includes the maximum value of the transmission delay difference between the PDU Sets associated with the first service flow and the second service flow.

4. The method according to any one of claims 1 to 3, characterized in that The access network device synchronously transmits the first PDU Set and the second PDU Set according to the first indication information and the association information, including: The access network device determines, according to the first indication information, that the first service flow is associated with the second service flow; The access network device determines, according to the association information, that the first PDU Set is associated with the second PDU Set; The access network device synchronously transmits the associated first PDU Set and the second PDU Set.

5. The method according to claim 4, characterized in that The first PDU Set and / or the second PDU Set carries association information, including: the first PDU Set carries first association information, and the second PDU Set carries second association information; The access network device determines, based on the association information, that the first PDU Set and the second PDU Set are associated, including: when the first association information and the second association information are the same, the difference between the first association information and the second association information is within a threshold range, or the difference between the first association information and the second association information is less than or equal to a threshold, the access network device determines that the first PDU Set and the second PDU Set are associated.

6. The method according to claim 5, characterized in that The threshold value comes from the core network.

7. The method according to claim 4, characterized in that The association information is used to indicate an offset value between identification information of PDU Sets associated with the first service flow and the second service flow; The first PDU Set further carries first identification information, and the second PDU Set further carries second identification information; The access network device determines, based on the association information, that the first PDU Set and the second PDU Set are associated, including: when a difference between the first identification information and the second identification information is equal to the offset value, the access network device determines that the first PDU Set and the second PDU Set are associated.

8. The method according to claim 4, characterized in that The method further includes: the access network device receiving, through control plane signaling, an offset value between associated information of the PDU Set associated between the first service flow and the second service flow from a user plane function network element or an application function network element; The first PDU Set and / or the second PDU Set carries association information, including: the first PDU Set carries first association information, and the second PDU Set carries second association information; The access network device determines, based on the association information, that the first PDU Set and the second PDU Set are associated, including: when a difference between the first association information and the second association information is equal to the offset value, the access network device determines that the first PDU Set and the second PDU Set are associated.

9. The method according to any one of claims 1 to 8, characterized in that The association information is included in a General Packet Radio Service Tunneling Protocol-User Plane GTP-U header of the PDU Set.

10. The method according to any one of claims 1 to 9, characterized in that The first indication information includes an identifier of the first service flow and an identifier of the second service flow; or, The first indication information includes an identifier of the first service flow, an identifier of a first session to which the first service flow belongs, an identifier of a first terminal device to which the first session belongs, an identifier of the second service flow, an identifier of a second session to which the second service flow belongs, and / or an identifier of a second terminal device to which the second session belongs.

11. A communication method, characterized in that: The method comprises: The user plane function network element obtains first indication information, where the first indication information is used to indicate that the first service flow and the second service flow are associated; The user plane function network element receives a first protocol data unit set PDU Set of the first service flow and a second PDU Set of the second service flow, where the first PDU Set carries third association information, and the second PDU Set carries fourth association information, where the third association information and the fourth association information are used by the user plane function network element to determine that the first PDU Set is associated with the second PDU Set; The user plane function network element adds association information to the first PDU Set and / or the second PDU Set according to the first indication information, the third association information, and the fourth association information, where the association information is used by the access network device to determine that the first PDU Set is associated with the second PDU Set; The user plane function network element sends the first PDU Set and the second PDU Set to the access network device.

12. The method according to claim 11, characterized in that The user plane function network element adds association information to the first PDU Set and / or the second PDU Set according to the first indication information, the third association information, and the fourth association information, including: The user plane function network element determines, according to the first indication information, that the first service flow is associated with the second service flow; The user plane function network element determines, according to the third association information and the fourth association information, that the first PDU Set is associated with the second PDU Set; The user plane functional network element adds the association information to the first PDU Set and / or the second PDU Set.

13. The method according to claim 12, characterized in that The user plane function network element determines, according to the third association information and the fourth association information, that the first PDU Set is associated with the second PDU Set, including: When the third association information and the fourth association information are the same, the difference between the third association information and the fourth association information is less than or equal to a threshold, the difference between the third association information and the fourth association information is within a threshold range, or the difference between the third association information and the fourth association information is equal to an offset value, the user plane functional network element determines that the first PDU Set and the second PDU Set are associated, and the offset value is the offset value between the association information of the associated PDU Sets between the first service flow and the second service flow.

14. The method according to claim 13, characterized in that The threshold value and / or the offset value comes from a session management function network element.

15. The method according to any one of claims 11 to 14, characterized in that The user plane function network element adds association information to the first PDU Set and / or the second PDU Set according to the first indication information, the third association information, and the fourth association information, including: The user plane function network element adds first association information to the first PDU Set and adds second association information to the second PDU Set according to the first indication information, the third association information and the fourth association information, and the first association information and the second association information are the same.

16. The method according to any one of claims 11 to 14, characterized in that The association information is used to indicate an offset value between identification information of PDU Sets associated with the first service flow and the second service flow; The method also includes: the user plane function network element adds first identification information to the first PDU Set and adds second identification information to the second PDU Set, the first identification information is the same as the third association information, and the second identification information is the same as the fourth association information.

17. The method according to claim 16, characterized in that The method further comprises: The user plane function network element determines the offset value according to the third association information and the fourth association information.

18. The method according to any one of claims 11 to 17, characterized in that The method further comprises: The user plane function network element obtains third indication information, where the third indication information is used to instruct the user plane function network element to identify an associated PDU Set.

19. The method according to claim 18, characterized in that The third indication information is also used to indicate a method for the user plane function network element to identify an associated PDU Set, and the method is any one of the following methods: identification based on a timestamp, or identification based on a PDU Set sequence number SN.

20. The method according to any one of claims 11 to 19, characterized in that The method further comprises: The user plane function network element obtains fourth indication information, where the fourth indication information is used to instruct the user plane function network element to mark an associated PDU Set.

21. The method according to any one of claims 11 to 20, characterized in that The first indication information includes an identifier of the first service flow and an identifier of the second service flow; or, The first indication information includes an identifier of the first service flow, an identifier of a first session to which the first service flow belongs, an identifier of a first terminal device to which the first session belongs, an identifier of the second service flow, an identifier of a second session to which the second service flow belongs, and / or an identifier of a second terminal device to which the second session belongs.

22. A communication method, characterized in that: The method comprises: The user plane function network element obtains fifth indication information, where the fifth indication information is used to indicate association information added by the user plane function network element to the first service flow, where the association information is used by the access network device to determine an associated protocol data unit set PDU Set between the first service flow and the second service flow; The user plane function network element receives a first PDU Set of the first service flow; The user plane function network element adds association information to the first PDU Set according to the fifth indication information; The user plane function network element sends the first PDU Set to the access network device.

23. The method according to claim 22, characterized in that The fifth indication information includes a third timestamp corresponding to the first service flow and a third PDU Set sequence number SN corresponding to the third timestamp, and the association information added by the user plane function network element to the first PDU Set is the first PDU Set SN; The adding associated information to the first PDU Set according to the fifth indication information includes: adding the first PDU Set SN to the first PDU Set according to the third timestamp, the third PDU Set SN and the first timestamp carried by the first PDU Set.

24. The method according to claim 23, characterized in that The method further includes: acquiring period information, where the period information is used to indicate a time interval between two adjacent PDU Sets of the first service flow; The adding the second PDU Set SN to the first PDU Set according to the third timestamp, the third PDU Set SN and the first timestamp carried by the first PDU Set includes: adding the first PDU Set SN to the first PDU Set according to the third timestamp, the third PDU Set SN, the first timestamp and the periodic information.

25. The method according to claim 22, characterized in that The fifth indication information includes an offset value of a PDU Set sequence number SN corresponding to the first service flow, and the association information added by the user plane function network element to the first PDU Set is a first PDU Set SN; The adding associated information to the first PDU Set according to the fifth indication information includes: adding the first PDU Set SN to the PDU Set according to the offset value and the fourth PDU Set SN carried by the first PDU Set, the first PDU Set SN being offset by the offset value relative to the fourth PDU Set SN.

26. A communication method, characterized in that: The method comprises: The user plane function network element and the access network device obtain first indication information, where the first indication information is used to indicate that the first service flow and the second service flow are associated; The user plane function network element receives a first protocol data unit set PDU Set of the first service flow and a second PDU Set of the second service flow, where the first PDU Set carries third association information, and the second PDU Set carries fourth association information, where the third association information and the fourth association information are used by the user plane function network element to determine that the first PDU Set is associated with the second PDU Set; The user plane function network element adds association information to the first PDU Set and / or the second PDU Set according to the first indication information, the third association information, and the fourth association information, where the association information is used by the access network device to determine that the first PDU Set is associated with the second PDU Set; The user plane function network element sends the first PDU Set and the second PDU Set to the access network device; The access network device synchronously transmits the first PDU Set and the second PDU Set according to the first indication information and the association information carried by the first PDU Set and / or the second PDU Set.

27. A communication method, characterized in that: The method comprises: The access network device obtains first indication information, where the first indication information is used to indicate that the first service flow and the second service flow are associated; The user plane function network element obtains fifth indication information, where the fifth indication information is used to indicate the user plane function network element to add association information to the first service flow and / or association information to the second service flow, where the association information is used to determine the first service flow and A protocol data unit set PDU Set associated between the second service flows; The user plane function network element receives a first PDU Set of the first service flow and a second PDU Set of the second service flow; adding association information to the first PDU Set and / or the second PDU Set according to the fifth indication information; The user plane function network element sends the first PDU Set and the second PDU Set to the access network device; The access network device synchronously transmits the first PDU Set and the second PDU Set according to the first indication information and the association information carried by the first PDU Set and / or the second PDU Set.

28. A communication device, characterized in that: The method comprises a module or a unit for executing the method as claimed in any one of claims 1 to 27.

29. A communication device, characterized in that: It includes a processor and an interface circuit, wherein the interface circuit is used to receive signals from other communication devices outside the communication device and transmit them to the processor or send signals from the processor to other communication devices outside the communication device, and the processor is used to implement the method as described in any one of claims 1 to 27 through logic circuits or execution code instructions.

30. A chip, characterized in that: The invention comprises a processor, wherein the processor is coupled to a memory, the memory is used to store a computer program, and the processor is used to execute the computer program stored in the memory to implement the method according to any one of claims 1 to 27.

31. A computer-readable storage medium, characterized in that: The storage medium stores a computer program or an instruction, and when the computer program or the instruction is executed by the communication device, the method according to any one of claims 1 to 27 is implemented.

32. A computer program product, characterized in that The invention comprises a computer program which, when being executed, implements the method according to any one of claims 1 to 27.

33. A communication system, characterized in that: A communication device comprising a method as claimed in any one of claims 1 to 10 and a communication device for executing the method as claimed in any one of claims 11 to 21, or a communication device for executing the method as claimed in any one of claims 1 to 10 and a communication device for executing the method as claimed in any one of claims 22 to 25.

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