Communication method and apparatus

Abstract

The present application relates to the technical field of communications, and provides a communication method and apparatus, aiming to reduce the possibility of network transmission congestion and improve the transmission efficiency. The method comprises: an access network device receives indication information, and reduces the air interface transmission redundancy of a service flow on the basis of the indication information, wherein the indication information is used for indicating that an application function has enabled redundant transmission of the service flow, and the redundant transmission of the service flow refers to the application function repeatedly sending data packets of the service flow.

Description

Communication method and device

[0001] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office on December 28, 2023, with application number 202311852482.9 and application name “Communication Method and 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 device. Background Art

[0003] With the rapid development of extended reality (XR) services, people are experiencing more immersive and interactive experiences. One way to implement XR services is cloud rendering, the essence of which is distributed collaborative image rendering technology between the terminal and the cloud. The terminal connects to the powerful computing resources of the cloud through the network, sends part of the rendering tasks to the cloud, and uses the computing power of the cloud for assistance. For example, the cloud is mainly responsible for rendering images with high computing power requirements, such as lighting data or backgrounds, and sends the image data to the terminal through the network. The terminal is mainly responsible for rendering low-quality images or images with low computing power requirements, such as foregrounds, and integrates the data provided by the cloud for secondary rendering, thereby reducing the performance requirements on the terminal side and achieving high-quality image rendering.

[0004] However, the amount of data in cloud rendering is relatively large, which can easily cause network transmission congestion and affect the terminal user experience. Summary of the Invention

[0005] The embodiments of the present application provide a communication method and apparatus to reduce the possibility of network transmission congestion and improve transmission efficiency.

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

[0007] In a first aspect, a communication method is provided for use with an access network device, comprising: the access network device receiving indication information and, based on the indication information, reducing air interface transmission redundancy of a service flow. The indication information indicates that an application function has enabled redundant transmission of the service flow. Redundant transmission of the service flow refers to the application function repeatedly sending data packets of the service flow.

[0008] As can be seen from the method described in the first aspect, for certain special service flows, such as XR service flows, the application function, upon detecting packet loss on the network, will enable redundant transmission of the service flow. For example, the application function will repeatedly send data packets for the service flow and notify the network, such as the access network device, of the indication that redundant transmission of the service flow has been enabled. In this way, the access network device can reduce the air interface transmission redundancy of the service flow based on the indication information, thereby reducing the possibility of network congestion and improving transmission efficiency.

[0009] In one possible design, the access network device receives the indication information, including: the access network device receiving an N2 message from an access and mobility management network element, wherein the N2 message includes the indication information. Specifically, the indication of enabled redundant transmission of a service flow can be delivered to the access network device by reusing existing control plane signaling to reduce implementation complexity, or can be delivered to the access network device via newly defined control plane signaling to achieve decoupling from existing signaling and more flexible signaling.

[0010] In one possible design scheme, the access network device receives indication information, including: the access network device receives data of a service flow from a user plane network element, wherein the data of the service flow includes indication information, thereby realizing user plane in-path delivery, which can reduce communication overhead compared to the method of control plane indication.

[0011] In one possible design, the access network device reduces air interface transmission redundancy of a service flow based on indication information, including: performing at least one of the following operations on the service flow based on the indication information: increasing the modulation order of the service flow, increasing the bit rate of the service flow, or improving the air interface transmission efficiency of the service flow. Increasing the modulation order or increasing the bit rate of the service flow can be understood as improving the air interface transmission efficiency of the service flow. In other words, reducing the air interface transmission redundancy of the service flow is equivalent to improving the air interface transmission efficiency of the service flow, transmitting as few redundant bits as possible, and thus reducing the possibility of network transmission congestion.

[0012] Optionally, at least one of the above operations is performed within the valid time of the channel status indication CQI, which is used to indicate the status of the channel carrying the service flow. It can be understood that the air interface transmission redundancy of the service flow corresponds to the CQI. For example, if the CQI indicates that the status of the channel carrying the service flow is relatively good, the air interface transmission redundancy of the service flow can be lowered according to the CQI to make the transmission efficiency higher. Conversely, if the CQI indicates that the status of the channel is relatively poor, the air interface transmission redundancy of the service flow can be increased according to the CQI to ensure the success rate of data transmission. Similarly, in the case where the application function performs redundant transmission of the service flow, the air interface transmission redundancy of the service flow also needs to be reduced according to the CQI. In other words, the redundant transmission part has been guaranteed by the application function, and the air interface transmission can reduce the redundancy appropriately to improve the transmission efficiency.

[0013] Optionally, the method described in the first aspect may further include: in the event of a CQI failure, the access network device triggering the terminal to perform channel measurement on the channel, and receiving the channel measurement result from the terminal. In this way, the access network device can determine a new CQI based on the measurement result and adjust the air interface transmission redundancy of the service flow according to the new CQI to ensure transmission efficiency.

[0014] In one possible design, before the access network device receives the indication information, the method described in the first aspect may further include: the access network device receiving redundant transmission capability information, where the redundant transmission capability information is used to indicate whether the application function supports redundant transmission. Furthermore, if the redundant transmission capability indicates that the application function supports redundant transmission, the access network device expects to receive information instructing the application function to enable redundant transmission. In other words, if the redundant transmission capability indicates that the application function does not support redundant transmission, the access network device may not expect to receive information instructing the application function to enable redundant transmission, that is, not perform reception detection on this information, thereby reducing overhead on the access network device.

[0015] In one possible design, the method described in the first aspect may further include: the access network device sending transmission status information to the application function, where the transmission status information is used to indicate the redundancy of the air interface transmission of the service flow, so that the application function can determine whether to enable redundant transmission of the service flow based on the redundancy of the air interface transmission of the service flow. For example, if the redundancy of the air interface transmission of the service flow is high, it means that the transmission of the service flow on the air interface has consumed a large amount of network resources, and the network may be congested or has already been congested. Therefore, the application function can decide not to enable redundant transmission of the service flow based on this, thereby avoiding network congestion or aggravation caused by the application function enabling redundant transmission of the service flow. Conversely, if the redundancy of the air interface transmission of the service flow is low, it means that the transmission of the service flow on the air interface has not consumed too many network resources, and the network has not been congested or the probability of congestion is low. Therefore, the application function can decide to enable redundant transmission of the service flow based on this to ensure the user's service experience.

[0016] Optionally, the transmission status information includes at least one of the following items of the service flow transmitted on the air interface: a modulation order of the service flow, a code rate of the service flow, or an air interface transmission efficiency of the service flow.

[0017] Optionally, the transmission status information is information determined within the valid time of the CQI. The CQI is used to indicate the status of the channel carrying the service flow to avoid the application function starting redundant transmission of the service flow when it should not be started due to the mismatch between the redundancy of the air interface transmission of the service flow and the status of the channel indicated by the CQI, thereby causing network congestion or aggravating network congestion.

[0018] Optionally, the method described in the first aspect may further include: in the event of a CQI failure, the access network device triggering the terminal to perform channel measurement on the channel, and receiving the channel measurement results from the terminal. In this way, the access network device can determine a new CQI based on the measurement results and report the transmission status information of the service flow according to the new CQI, thereby preventing application functions from enabling redundant transmission of service flows when they should not, thereby causing or exacerbating network congestion.

[0019] A second aspect provides a communication method for an application function, comprising: the application function receiving transmission status information from a network and determining, based on the transmission status information, whether to enable redundant transmission of a service flow. The transmission status information indicates the redundancy of air interface transmission of the service flow of the application function. Redundant transmission of a service flow refers to the application function repeatedly sending data packets of the service flow to the network.

[0020] As can be seen from the method described in the second aspect, since the application function can perceive the redundancy of the air interface transmission of the service flow, the more redundant the air interface transmission of the service flow, the greater the possibility of network congestion, and vice versa. Therefore, the application function can decide whether to enable redundant transmission of the service flow based on the redundancy of the air interface transmission of the service flow, so as to avoid the application function enabling redundant transmission of the service flow when it should not, causing or exacerbating network congestion.

[0021] In one possible design, the transmission status information includes at least one of the following items of the service flow transmitted on the air interface: a modulation order of the service flow, a code rate of the service flow, or an air interface transmission efficiency of the service flow.

[0022] In one possible design, an application function determines whether to enable redundant transmission of a service flow based on transmission status information, including: determining a priority for redundant transmission of the service flow based on the transmission status information, and determining whether to enable redundant transmission of the service flow based on the priority of the redundant transmission of the service flow. For example, if the transmission status information indicates a higher degree of redundancy in the air interface transmission of the service flow, the priority of the redundant transmission of the service flow will be lower. In other words, the application function will be less likely to enable redundant transmission of the service flow, thereby avoiding network congestion or exacerbated network congestion caused by enabling redundant transmission of the service flow.

[0023] In a possible design scheme, the method described in the second aspect may also include: the application function sends indication information to the network, wherein the indication information is used to indicate that the application function has enabled redundant transmission of the service flow.

[0024] Optionally, the application function sends indication information to the network, including: the application function sends a service flow creation / modification request message to the network, where the service flow creation / modification request message includes the indication information.

[0025] Optionally, the application function sends indication information to the network, including: the application function sends a service flow data packet to a user plane network element in the network, and the data of the service flow includes the indication information.

[0026] In a possible design scheme, the method described in the second aspect may further include: the application function sends redundant transmission capability information to the network, wherein the redundant transmission capability information is used to indicate whether the application function supports redundant transmission.

[0027] It can be understood that the technical effects of the method described in the second aspect can also refer to the relevant introduction of the method described in the first aspect, and will not be repeated here.

[0028] According to a third aspect, a communication device is provided, comprising a module for executing the method according to the first aspect or the second aspect.

[0029] In one possible design solution, the communication device described in the third aspect may further include a transceiver. The transceiver may be a transceiver circuit or an interface circuit. The transceiver may be used for the communication device described in the third aspect to communicate with other communication devices.

[0030] In one possible design solution, the communication device described in the third aspect may further include a memory. The memory may be integrated with the processor or provided separately. The memory may be used to store instructions involved in the method of the first aspect or the second aspect.

[0031] In an embodiment of the present application, the communication device described in the third aspect may be a network device, or a chip (system) or other parts or components that can be set in the network device, or a device that includes the network device.

[0032] It can be understood that the technical effects of the device described in the third aspect can also refer to the relevant introduction of the method of the first aspect or the second aspect above, and will not be repeated here.

[0033] In a fourth aspect, a communication device is provided, comprising: a processor coupled to a memory, the processor configured to execute instructions stored in the memory, so that the communication device performs the method described in the first aspect or the second aspect.

[0034] In one possible design solution, the communication device described in the fourth aspect may further include a transceiver. The transceiver may be a transceiver circuit or an interface circuit. The transceiver may be used for the communication device described in the fifth aspect to communicate with other communication devices.

[0035] In an embodiment of the present application, the communication device described in the fourth aspect may be the network device described in the first aspect or the second aspect, or a chip (system) or other parts or components that can be set in the network device, or a device that includes the network device.

[0036] In addition, the technical effects of the communication device described in the fourth aspect can refer to the technical effects of the method described in the first aspect or the second aspect, and will not be repeated here.

[0037] In a fifth aspect, a communication device is provided, comprising: a processor and a memory; the memory is used to store instructions, and when the processor executes the instructions, the communication device executes the method described in the first aspect or the second aspect.

[0038] In one possible design solution, the communication device described in the fifth aspect may further include a transceiver. The transceiver may be a transceiver circuit or an interface circuit. The transceiver may be used for the communication device described in the fifth aspect to communicate with other communication devices.

[0039] In an embodiment of the present application, the communication device described in the fifth aspect may be the network device described in the first aspect or the second aspect, or a chip (system) or other parts or components that may be set in the network device, or a device that includes the network device.

[0040] In addition, the technical effects of the communication device described in the fifth aspect can refer to the technical effects of the method described in the first aspect or the second aspect, and will not be repeated here.

[0041] In a sixth aspect, a chip is provided, comprising: a controller and an interface circuit, wherein the controller is used to interact with other devices through the interface circuit to execute the method described in the first aspect or the second aspect.

[0042] In a seventh aspect, a communication system is provided, which includes at least one of the following: an access network device for executing the method described in the first aspect, and an application function for executing the method described in the second aspect.

[0043] In an eighth aspect, a computer-readable storage medium is provided, which includes a computer program or instruction stored therein, and when the computer program or instruction is run, the method described in the first aspect or the second aspect is executed.

[0044] In a ninth aspect, a computer program product is provided, comprising a computer program or instructions, which, when executed, causes the method described in the first aspect or the second aspect to be executed. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 is a schematic diagram of the 5GS architecture;

[0046] Figure 2 is a schematic diagram of a cloud rendering scene;

[0047] Figure 3 is a schematic diagram of AF transmission in a cloud rendering environment;

[0048] FIG4 is a schematic diagram of the architecture of a communication system provided in an embodiment of the present application;

[0049] FIG5 is a flow chart of a communication method according to an embodiment of the present application;

[0050] FIG6 is a second flow chart of the communication method provided in an embodiment of the present application;

[0051] FIG7 is a third flow chart of the communication method provided in an embodiment of the present application;

[0052] FIG8 is a fourth flow chart of a communication method according to an embodiment of the present application;

[0053] FIG9 is a first structural diagram of a communication device provided in an embodiment of the present application;

[0054] FIG10 is a second structural diagram of the communication device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0055] The technical solutions of the embodiments of the present application can be applied to various communication systems, such as wireless network (Wi-Fi) systems, vehicle to everything (V2X) communication systems, device-to-device (D2D) communication systems, Internet of Vehicles communication systems, fourth-generation (4G) mobile communication systems, such as long-term evolution (LTE) systems, world-wide interoperability for microwave access (WiMAX) communication systems, fifth-generation (5G) mobile communication systems, such as new radio (NR) systems, and future communication systems, such as 5.5G and sixth-generation (6G) mobile communication systems.

[0056] For ease of understanding, the technical terms involved in the embodiments of this application are first introduced below.

[0057] 1. Fifth generation (5G) mobile communication system (abbreviated as 5G system (5G system, 5GS)):

[0058] Figure 1 is a schematic diagram of the 5GS architecture. As shown in Figure 1, the 5GS includes an access network (AN) and a core network (CN), and may also include terminals.

[0059] The terminal may be a terminal with transceiver functions, or a chip or chip system that can be provided in the terminal. The terminal may also be referred to as user equipment (UE), access terminal, subscriber unit, user station, mobile station (MS), mobile station, remote station, remote terminal, mobile device, user terminal, terminal, wireless communication device, user agent, or user device. The terminal in the embodiments of the present application can be a mobile phone, a cellular phone, a smart phone, a tablet computer, a wireless data card, a personal digital assistant (PDA), a wireless modem, a handset, a laptop computer, a machine type communication (MTC) terminal, a computer with wireless transceiver function, 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, a wireless terminal in smart grid, a wireless terminal in transportation safety, a wireless terminal in smart city, a wireless terminal in smart home, a vehicle-mounted terminal, a road side unit (RSU) with terminal function, etc. The terminal of the present application may also be an on-board module, on-board module, on-board component, on-board chip or on-board unit built into the vehicle as one or more components or units.

[0060] The AN implements access-related functions, providing network access for authorized users and determining transmission links of varying quality for user data based on user level and service requirements. The AN forwards control signals and user data between terminals and the CN. The AN may include access network equipment, also known as radio access network (RAN) equipment.

[0061] The CN is primarily responsible for maintaining mobile network subscription data and providing terminal functions such as session management, mobility management, policy management, and security authentication. The CN primarily includes all or part of the following functions: user plane function (UPF), authentication server function (AUSF), access and mobility management function (AMF), session management function (SMF), network slice selection function (NSSF), network exposure function (NEF), network repository function (NRF), policy control function (PCF), unified data management (UDM), unified data repository (UDR), and application function (AF).

[0062] As shown in Figure 1, the UE accesses the 5G network through the RAN equipment. The UE communicates with the AMF through the N1 interface (referred to as N1); the RAN communicates with the AMF through the N2 interface (referred to as N2); the RAN communicates with the UPF through the N3 interface (referred to as N3); the SMF communicates with the UPF through the N4 interface (referred to as N4), and the UPF accesses the data network (DN) through the N6 interface (referred to as N6). In addition, the control plane functions such as AUSF, AMF, SMF, NSSF, NEF, NRF, PCF, UDM, UDR or AF shown in Figure 1 interact using service-based interfaces. For example, the service interface provided by AUSF to the outside world is Nausf; the service interface provided by AMF to the outside world is Namf; the service interface provided by SMF to the outside world is Nsmf; the service interface provided by NSSF to the outside world is Nnssf; the service interface provided by NEF to the outside world is Nnef; the service interface provided by NRF to the outside world is Nnrf; the service interface provided by PCF to the outside world is Npcf; the service interface provided by UDM to the outside world is Nudm; the service interface provided by UDR to the outside world is Nudr; and the service interface provided by AF to the outside world is Naf.

[0063] The RAN device may be a device that provides access to the terminal. For example, the RAN device may include: a next-generation mobile communication system, such as an access network device of 6G, such as a 6G base station, or in the next-generation mobile communication system, the network device may also have other naming methods, which are all included in the protection scope of the embodiments of the present application, and the present application does not impose any restrictions on this. Alternatively, the RAN device may also include 5G, such as a gNB in ​​a new radio (NR) system, or one or a group of (including multiple antenna panels) antenna panels of a base station in 5G, or a network node constituting a gNB, a transmission point (TRP or transmission point, TP) or a transmission measurement function (TMF), such as a baseband unit (BBU), or a centralized unit (CU) or a distributed unit (DU), an RSU with base station function, or a wired access gateway, or a 5G core network. Alternatively, RAN devices may also include access points (APs) in wireless fidelity (WiFi) systems, wireless relay nodes, wireless backhaul nodes, various forms of macro base stations, micro base stations (also known as small stations), relay stations, access points, wearable devices, vehicle-mounted devices, and the like.

[0064] UPF is mainly responsible for user data processing (forwarding, receiving, billing, etc.). For example, UPF can receive user data from the data network (DN) and forward the user data to the terminal through the access network equipment. UPF can also receive user data from the terminal through the access network equipment and forward the user data to the DN. DN refers to the operator network that provides data transmission services to users. For example, the Internet Protocol (IP) Multimedia Service (IMS), the Internet, etc. DN can be an operator's external network or a network controlled by the operator, used to provide business services to the terminal. In the protocol data unit (PDU) session, the UPF directly connected to the DN through N6 is also called the protocol data unit session anchor (PSA).

[0065] AUSF is mainly used to perform terminal security authentication.

[0066] AMF is mainly used for mobility management in mobile networks, such as user location update, user network registration, and user handover.

[0067] The SMF is primarily used for session management in mobile networks, such as session establishment, modification, and release. Specific functions include allocating Internet Protocol (IP) addresses to users and selecting the UPF that provides packet forwarding capabilities.

[0068] PCF primarily supports providing a unified policy framework to control network behavior, providing policy rules to the control layer network functions, and is responsible for obtaining user subscription information related to policy decisions. PCF can provide policies to AMF and SMF, such as quality of service (QoS) policies and slice selection policies.

[0069] NSSF is mainly used to select network slices for terminals.

[0070] NEF is mainly used to support the opening of capabilities and events.

[0071] UDM is mainly used to store user data, such as contract data, authentication / authorization data, etc.

[0072] UDR is mainly used to store structured data, including contract data and policy data, externally exposed structured data, and application-related data.

[0073] AF mainly supports interaction with CN to provide services, such as influencing data routing decisions, policy control functions, or providing some third-party services to the network side.

[0074] It can be understood that the functions mentioned in the embodiments of the present application can also be expressed as functional network elements or functional entities. For example, UPF can be expressed as UPF network element, AMF can be expressed as AMF network element, SMF can be expressed as SMF network element, PCF can be expressed as PCF network element, and so on, without limitation.

[0075] 2. PDU set:

[0076] In 5G networks, network functional entities interact with each other by transmitting IP packets. The data units transmitted in these IP packets are called PDUs. A PDU set is a group of interrelated PDUs that complete a specific task. Together, these PDUs form a complete data set.

[0077] PDU Set-based handling refers to a strategy for setting PDU-related attributes in 5G networks based on the QoS information of data packets. Specifically, 5G networks provide different levels of QoS guarantees for different applications, requiring data streams (streaming video, voice calls, etc.) to be assigned to QoS flows with different QoS attributes. As the basic unit of data transmission in 5G networks, the PDU contains QoS information to implement QoS-based PDU Set-based QoS handling. For example, the network can set other attributes of the PDU, such as priority, throughput, and transmission delay, based on the QoS information (such as the QoS flow ID) that identifies the QoS flow in the PDU. For example, for a high-priority QoS flow corresponding to real-time audio / video data, its PDU can be set with high priority and low transmission delay attributes; for a low-priority QoS flow corresponding to non-real-time data, its PDU attributes can be set with more relaxed properties to ensure that the 5G network provides corresponding levels of service quality for different QoS flows.

[0078] The TS23.501 protocol (Section 5.37.5) defines the QoS-based processing method for PDU SET. The basic idea of ​​the solution is as follows:

[0079] 1) AF provides information such as flow characteristics and QoS requirements related to PDU sets.

[0080] 2) The PCF network element generates policy and charging control (PCC rules) for the PDU set based on the information provided by the AF.

[0081] 3) The UPF network element identifies the data packets belonging to the same PDU set (PDU Sequence Number within a PDU Set) and the PDU set importance (PDU Set Importance).

[0082] 4) The UPF network element transmits relevant information of the PDU set to the RAN equipment (carried by the general packet radio service (GPRS) tunneling protocol for the user plane (GTP-U) header).

[0083] 5) The PCF network element generates the QoS specifications of the PDU set (PDU Set QoS parameters) based on the information provided by the AF and sends it to the RAN device through the SMF network element.

[0084] 6) The RAN device performs QoS-based PDU aggregation processing based on the QoS specification of the received PDU aggregation.

[0085] In addition, the prior art also involves the SMF network element indicating the protocol description of the header, extended header (such as real-time transport protocol (RTP) RTP / secure real-time transport protocol (SRTP) and payload type (such as video coding standard (H.264)) used in the service data flow to the UPF network element. The UPF network element uses the corresponding protocol description to identify the relevant information of the PDU set and passes it to the RAN device through the GTP-U header. The RAN device performs QoS-based PDU set processing.

[0086] 3. Openness of network information:

[0087] How the application layer perceives network conditions, or how to expose network status information to applications, is a critical issue that requires urgent research. For example, how can the application layer perceive network status in real time and make corresponding content adjustments to ensure user experience and improve network utilization efficiency? For example, network information can be exposed to third-party applications through control plane capability exposure interfaces. This could be done directly through the service-oriented interfaces of the UPF network element, or by using the NEF network element. Alternatively, using the Release 16 solution, the UPF network element sends measurement results to the SMF network element, which then exposes this network information to third-party applications through the NEF network element, enabling rapid, real-time exposure of network information.

[0088] Understandably, due to the potential security risks inherent in RAN equipment, 3GPP standards typically don't define the RAN as being able to directly expose network information. Instead, the RAN equipment must first communicate the monitored network information to core network nodes, such as the UPF network element, which then makes it available. Alternatively, the RAN equipment can embed network information into data packets via the user plane and transmit them to the UE or application server, also enabling network information disclosure.

[0089] For easier understanding, the following uses open network congestion information as an example to introduce it.

[0090] As an implementation solution, the industry introduced low latency, low loss, scalable throughput (L4S) into 3GPP and used it for the rapid and real-time disclosure of 5GS network capability information, for example, the disclosure of network congestion information by RAN equipment.

[0091] Specifically, explicit congestion notification (ECN) uses two bits in the Internet Protocol version 4 (IPv4) header as ECN flags, notifying the sender or receiver of congestion at a transmission node so that the sender can drop corresponding packets to reduce the possibility of congestion. For example, a CE flag value of 11 indicates congestion during the current network transmission process, while other CE flag values, such as "00," "01," and "10," indicate whether ECN is supported. This allows an end-to-end client to determine whether the peer supports the ECN mechanism through the ECN flag, enabling bidirectional capability negotiation.

[0092] L4S is an upgrade based on the ECN mechanism, further expanding the role of the original ECN flag. For example, by counting the proportion of packets marked as congested (i.e., with an ECN flag of "11") within a period of time, the degree of network congestion can be determined. In other words, even if the network may not be congested at the moment, the L4S mechanism can still perceive the current network status, allowing the sender or receiver to adjust based on the network congestion information. For example, for media services, the sender may adjust the sending bitrate in real time based on network congestion information. In addition, the two-way capability negotiation of L4S also refers to the ECN mechanism, using the ECN flag in the IP header to indicate whether the other end supports L4S capabilities.

[0093] There are two existing implementation schemes: RAN equipment executes L4S and UPF network elements execute L4S.

[0094] 1) RAN equipment performs L4S:

[0095] RAN equipment can monitor the network congestion status of corresponding QoS flows and perform L4S marking based on the network congestion status, thereby enabling the on-path disclosure of network congestion information. The details are described below.

[0096] Downlink scenario:

[0097] The RAN device can determine the downlink network congestion status based on the network status of the corresponding QoS flow or the network status of the data radio bearer (DRB) corresponding to the corresponding QoS flow, such as available bandwidth, bandwidth utilization, and air interface data transmission queue length. For example, the proportion of downlink data packets with a congestion experienced (CE) indicator of "11" is used as network congestion information. In other words, the network congestion information indicates the proportion of downlink data packets with a CE indicator of "11." Based on the network congestion status, the RAN device can add a corresponding CE indicator, such as "11," to the IP header of the downlink data packet through the Layer 4 Service (L4S) mechanism, thereby implementing L4S marking. The UE will perform corresponding statistics, such as counting the number or proportion of downlink data packets with a CE indicator value of "11," to determine the network congestion status. For example, if the number of data packets carrying the value "11" accounts for 40% of all received data packets, it can be considered that the probability of network congestion in the current network, the current QoS flow, or the DRB corresponding to the current QoS flow is 40%. The UE can inform the sender of the above network congestion status through upper-layer feedback mechanisms, such as the transmission control protocol (TCP) acknowledgment (ACK) feedback, the real-time transport control protocol (RTCP) feedback report, and the ACK mechanism of the user datagram protocol (UDP)-based low-latency Internet transport layer protocol (quick UDP internet connection, QUIC), such as the application server (AS) receiving the probability of network congestion from the UE side. Accordingly, the AS can dynamically adjust the bit rate based on the network congestion status obtained through feedback, thereby ensuring the user's service experience. It should be understood that how the RAN device determines the network congestion status of the QoS flow or the DRB corresponding to the QoS flow depends on the self-implementation of the RAN device and is not limited here.

[0098] Uplink scenario:

[0099] The RAN equipment can determine the uplink network congestion status based on the network status of the corresponding QoS flow or the network status of the DRB corresponding to the QoS flow, and use the L4S mechanism to add the corresponding CE identifier, such as "11", to the IP header of the uplink data packet. The receiving end, the application server (AS), can perform corresponding statistics, such as counting the number or proportion of uplink data packets with the CE identifier value of "11", and feedback this information to the transmitting end, the UE, to instruct the UE to dynamically adjust the bit rate to ensure the user experience. The specific implementation method is similar to the downlink scenario and is not detailed here.

[0100] 2) UPF network element executes L4S:

[0101] The RAN device can monitor the network congestion status of the corresponding QoS flow or the DRB corresponding to the QoS flow, and send the network congestion status to the UPF network element through the GTP-U layer of the uplink data packet. The UPF network element performs L4S marking based on the network congestion status provided by the RAN device. The specific implementation is similar to that of the above-mentioned RAN device. You can refer to it for understanding and will not repeat it here. In this way, the network congestion information can also be opened to the outside world. It should be understood that how the RAN device determines the network congestion status of the QoS flow or the DRB corresponding to the QoS flow depends on the self-implementation of the RAN device and is not limited here.

[0102] 4. Extended Reality (XR) Business:

[0103] With the rapid development of XR services, computing power requirements are rapidly increasing. The emergence of these emerging technologies brings us more immersive and interactive experiences, but also places higher demands on computing resources. Currently, computing power improvements on devices (such as mobile phones, tablets, and augmented reality (AR) / virtual reality (VR) devices) are limited, widening the gap with personal computers (PCs) and cloud computing. For example, the computing power of AI chips for PCs and cloud computing has increased from 4 trillion operations per second (TOPs) in 2012 to 1248 TOPs in 2021, a 315-fold increase in just nine years. However, the gains in computing power and energy efficiency brought about by device chip technology are gradually declining. Therefore, to meet computing power demands, end-cloud collaboration will become a key solution to meet these needs, providing people with richer, more immersive, and interactive digital experiences.

[0104] As shown in Figure 2, cloud rendering is a major application scenario for end-cloud collaboration. Specifically, it can be end-cloud collaborative rendering. For example, cloud rendering is essentially end-cloud distributed collaborative image rendering technology. Unlike traditional centralized terminal rendering, the terminal connects to the cloud's powerful computing resources via the network and sends some rendering tasks to the cloud. The cloud's powerful computing power provides assistance, thereby reducing the performance requirements on the terminal side, achieving high-quality image rendering, and enabling low-spec terminals to experience PC-level high-quality rendering effects. Specifically, end-cloud collaborative rendering mainly involves cloud-based ray tracing rendering, and the terminal integrates ray tracing data to enhance image effects. For example, the cloud is primarily responsible for rendering high-computing-power-demanding images such as lighting data or backgrounds, while the terminal is primarily responsible for rendering low-quality images or low-computing-power-demand images such as foregrounds, and then integrates the cloud results for secondary rendering.

[0105] As shown in Figure 3, through performance testing of end-to-end cloud collaborative rendering, it was found that AF on the application side can sense network packet loss. If AF senses that packet loss has occurred, it will enable redundant transmission to combat network packet loss. Using packet capture software, it was found that the following situation exists: in the case of packet loss, the size of the AF's redundantly transmitted data packet is reduced by 2 / 3 (580 bytes --> 140 bytes), while the packet transmission volume increases by more than 4 times (for example, 200 packets / second (packets / s) --> 1000 packets / second), and the downlink data bandwidth increases by more than 2 times (50 kilobits per second (KBps) --> 150KBps). In addition, the current phenomenon of AF using redundant transmission to combat network packet loss is widespread.

[0106] However, as we've seen with the aforementioned network-side packet scheduling, RAN equipment uses PDU aggregation as the granularity, such as QoS-based PDU aggregation processing. The network is unaware of AF redundant transmission. Therefore, if the network loses packets due to congestion, enabling redundant transmission in AF could further exacerbate network congestion and impact the user experience.

[0107] In response to the above technical problems, the embodiments of the present application propose the following technical solutions.

[0108] The technical solution in this application will be described below with reference to the accompanying drawings.

[0109] In the embodiment of the present application, "indication" may include direct indication and indirect indication, and may also include explicit indication and implicit indication. The information indicated by a certain information is called information to be indicated. In the specific implementation process, there are many ways to indicate the information to be indicated, such as but not limited to, the information to be indicated can be directly indicated, such as the information to be indicated itself or the index of the information to be indicated. The information to be indicated can also be indirectly indicated by indicating other information, wherein there is an association relationship between the other information and the information to be indicated. It is also possible to indicate only a part of the information to be indicated, while the other parts of the information to be indicated are known or agreed in advance. For example, the indication of specific information can also be achieved by means of the arrangement order of each piece of information agreed in advance (such as specified in the protocol), thereby reducing the indication overhead to a certain extent. At the same time, the common parts of each piece of information can also be identified and indicated uniformly to reduce the indication overhead caused by indicating the same information separately.

[0110] In addition, the specific indication method can also be various existing indication methods, such as but not limited to the above-mentioned indication methods and various combinations thereof. The specific details of the various indication methods can be referred to the prior art and will not be repeated herein. As can be seen from the above, for example, when it is necessary to indicate multiple information of the same type, there may be a situation where the indication methods for different information are different. In the specific implementation process, the required indication method can be selected according to specific needs. The embodiment of the present application does not limit the selected indication method. In this way, the indication method involved in the embodiment of the present application should be understood to cover various methods that can enable the party to be indicated to obtain the information to be indicated.

[0111] It should be understood that the information to be indicated can be sent as a whole or divided into multiple sub-information and sent separately, and the sending period and / or sending time of these sub-information can be the same or different. The specific sending method is not limited in the embodiments of this application. The sending period and / or sending time of these sub-information can be predefined, for example, predefined according to a protocol, or can be configured by the transmitting device by sending configuration information to the receiving device.

[0112] In this application, "sending information" can be understood as one device sending information to another device, or as one logic module within a device sending information to another logic module. For example, "a network device sending information" can be understood as a network device sending information to another device (such as a terminal or other network device), or as logic module 1 within a network device sending information to logic module 2 within the network device.

[0113] In this application, "receiving information" can be understood as one device receiving information from another device, or it can also be understood as a logic module within a device receiving information from another logic module. For example, "a network device receiving information" can be understood as the network device receiving information from another device (such as a terminal or other network device), or it can be understood as logic module 1 in the network device receiving information from logic module 2 in the network device.

[0114] In this application, "sending information to... (e.g., a terminal)" or the related illustrations in the accompanying drawings can be understood as the destination end of the information being the terminal. This can include sending information to the terminal directly or indirectly. "Receiving information from... (e.g., a terminal)" or "receiving information from... (e.g., a terminal)" or "receiving information sent by (e.g., a terminal)", or the related illustrations in the accompanying drawings can be understood as the source end of the information being the terminal, which can include receiving information from the terminal directly or indirectly. The information may be processed as necessary between the source end and the destination end of the information transmission, such as format changes, etc., but the destination end can understand the valid information from the source end. Similar expressions in this application can be understood similarly and will not be repeated here.

[0115] "Pre-definition" or "pre-configuration" can be implemented by pre-saving corresponding codes, tables or other methods that can be used to indicate relevant information in the device, and the embodiments of the present application do not limit the specific implementation method. Among them, "saving" can mean saving in one or more memories. The one or more memories can be set separately or integrated in an encoder or decoder, a processor, or a communication device. The one or more memories can also be partially set separately and partially integrated in a decoder, a processor, or a communication device. The type of memory can be any form of storage medium, and the embodiments of the present application do not limit this.

[0116] The "protocol" involved in the embodiments of the present application may refer to a protocol family in the communication field, a standard protocol with a similar protocol family frame structure, or a related protocol used in future communication systems. The embodiments of the present application do not make specific limitations on this.

[0117] In the embodiments of the present application, descriptions such as "when...", "in the case of...", "if" and "if" all mean that the device will perform corresponding processing under certain objective circumstances. It does not limit the time, nor does it require the device to perform judgment actions when implemented, nor does it mean that there are other limitations.

[0118] In the description of the embodiments of the present application, unless otherwise specified, " / " indicates that the objects associated with each other are in an "or" relationship. For example, A / B can represent A or B. "And / or" in the embodiments of the present application is only a description of the association relationship of the associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. A and B can be singular or plural. In addition, in the description of the embodiments of the present application, unless otherwise specified, "multiple" refers to two or more than two. "At least one of the following" 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, or c can represent: a, b, c, ab, ac, bc, or abc, where a, b, and c can be single or multiple. In addition, in order to facilitate the clear description of the technical solutions of the embodiments of the present application, in the embodiments of the present application, words such as "first" and "second" are used to distinguish between identical or similar items with basically the same functions and effects. Those skilled in the art will understand that words such as "first" and "second" do not limit the quantity and execution order, and words such as "first" and "second" do not necessarily limit differences. At the same time, in the embodiments of the present application, words such as "exemplary" or "for example" are used to indicate examples, illustrations or explanations. Any embodiment or design described as "exemplary" or "for example" in the embodiments of the present application should not be interpreted as being more preferred or more advantageous than other embodiments or design. Specifically, the use of words such as "exemplary" or "for example" is intended to present related concepts in a concrete way for easy understanding.

[0119] 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 will 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.

[0120] To facilitate understanding of the embodiments of the present application, a communication system applicable to the embodiments of the present application is first described in detail using a communication system as an example.

[0121] As shown in FIG4 , illustratively, the communication system mainly includes at least one of the following: access network equipment and application functions.

[0122] The access network device may be the RAN device in the above-mentioned 5GS, or in future communication systems, any network element / entity / device that can be used to implement the access function can be understood as the access network device in the embodiments of this application. The application function may be the AF in the above-mentioned 5GS, or in future communication systems, any network element / entity / device that can be used to implement the application-side function can be understood as the application function in the embodiments of this application.

[0123] In the case where the application function enables redundant transmission of the service flow, the application function can inform the access network device of the indication information of the enabled redundant transmission of the service flow, so that the access network device can reduce the air interface transmission redundancy of the service flow, thereby reducing the possibility of network congestion. Alternatively, the access network device can open the transmission status information of the service flow, such as the redundancy of the air interface transmission of the service flow, to the application function through network information opening, so that the application function can determine whether to enable redundant transmission of the service flow based on this. For example, if the redundancy level of the air interface transmission of the service flow is high, it means that the transmission of the service flow at the air interface has consumed a lot of network resources, and the network may be congested or has already been congested. Therefore, the application function can decide not to enable redundant transmission of the service flow based on this, so as to avoid network congestion or aggravation of network congestion caused by the application function enabling redundant transmission of the service flow.

[0124] It is understood that the service flow mentioned in the embodiments of the present application can be a data flow composed of data of a service (such as a video service, an audio service, etc.). The data flow can be identified by the IP quintuple / IP triplet of the data packet, the type of service (ToS) of the IPv4 header, and / or the flow label of the IPv6 header. Therefore, the IP quintuple / IP triplet / ToS / flow label is also called information for indicating the service flow, or flow description information of the service flow.

[0125] A service can have one or more service flows, and these service flows can each have their own QoS flow or share a QoS flow (such as the service flows of the same service share a QoS flow, or share a QoS flow with the service flows of other services). Therefore, the service flow can also be represented by the QoS flow that carries the service flow. For RAN equipment, since RAN equipment usually does not perceive specific services, the service flow can be the QoS flow that carries the service flow for the RAN equipment. For UPF network elements, UPF network elements can perceive the service flow and the QoS flow corresponding to the service flow. If the UPF network element opens network information or perceives redundancy at the granularity of service flow, the UPF network element can process the service flow of a known service; if the UPF network element opens network information or perceives redundancy at the granularity of QoS flow, the UPF network element can process the QoS flow that carries the service flow.

[0126] The following will specifically describe the interaction process between each network element / device in the above communication system through a method embodiment in conjunction with Figures 5 to 9. The communication method provided in the embodiment of the present application can be applied to the above communication system and specifically applied to various scenarios mentioned in the above communication system, which will be described in detail below.

[0127] Figure 5 is a flow chart of a communication method according to an embodiment of the present application. The communication method is applicable to the above-mentioned communication system and mainly involves the interaction between the access network device and the application function.

[0128] As shown in Figure 5, the process of the communication method is as follows:

[0129] S501: The access network device receives instruction information.

[0130] Indication information (denoted as indication information #1) can be used to indicate that the application function has enabled redundant transmission of a service flow. For example, indication information #1 may include relevant information about the service flow. Specifically, the relevant information about the service flow may be an identifier of the QoS flow carrying the service flow, such as a QFI. Furthermore, indication information #1 may also include an indication information element. This indication information element is a one-bit information element that, through its two values ​​of 0 / 1 and the relevant information about the service flow, indicates whether the application function has enabled redundant transmission of the service flow. Alternatively, it can be understood as indicating whether the application function has enabled redundant transmission of the QoS flow carrying the service flow. For another example, indication information #1 may only include relevant information about the service flow. In this case, indication information #1 may be information received only when the application function has enabled redundant transmission of the service flow. If the access network device receives indication information #1, it indicates that the application function has enabled redundant transmission of the service flow. Otherwise, the application function has not enabled redundant transmission of the service flow. For another example, if the access network device knows the service flow in advance, indication information #1 may also include only the indication information element.

[0131] Redundant transmission of a service flow refers to the application function repeatedly sending data packets of the service flow. For example, the application function repeats the data packet of the service flow multiple times by default, regardless of whether the data packet of the service flow is lost. The application function can repeat all data packets of the service flow, or the application function can repeat only some data packets. This portion of data packets can be data packets randomly selected by the application function based on the proportion of data packets to be repeated, such as the application function randomly selecting 1 / 2 of the data packets to be repeated, or they can be data packets selected by the application function according to a preset rule, such as the application function selecting to repeat the first 1 / 2 of the data packets or the last 1 / 2 of the data packets.

[0132] Different data packets in a service flow may be repeatedly sent the same number of times by the application function, such as being repeatedly sent 2 or 4 times, or different data packets in a service flow may be repeatedly sent the same number of times by the application function, such as data packet 1 being repeatedly sent 2 times by the application function, and data packet 2 being sent 4 times by the application function, etc. The specific number of times may be selected by the application function based on actual conditions. For example, the application function may repeatedly send a service flow according to a preset number of repetitions (such as 2 or 4 times) during redundant transmission. For another example, the application function may dynamically adjust the number of repetitions during redundant transmission of the service flow, such as initially retransmitting the service flow according to a number of repetitions of 4, and then retransmitting the service flow according to a number of repetitions of 2 as the packet loss rate decreases.

[0133] The application function can determine whether to enable redundant transmission of a service flow based on the packet loss rate of the service flow. For example, if the packet loss rate of a service flow reported by the terminal exceeds the packet loss rate threshold, such as a 6% packet loss rate and a 5% packet loss rate threshold, the application function will enable redundant transmission of the service flow. Otherwise, redundant transmission of the service flow will not be enabled. Therefore, when enabling redundant transmission of a service flow, the application function can send an indication message (referred to as indication message #2) to the network.

[0134] The network may be an operator network, such as a public land mobile network (PLMN), or in future communication systems, the network may be any possible type of network, such as a 6G network, in which access network equipment is deployed to carry the service flow.

[0135] Indication information #2 can also be used to indicate that the application function has enabled redundant transmission of the service flow. Indication information #2 can be different from indication information #1. For example, indication information #2 can include the identifier of the service flow, specifically the flow description information of the service flow (the application function may not be aware of the QoS flow), and indication information #2 can also include the above-mentioned indication information element. For another example, indication information #2 can also only include the identifier of the service flow, such as the flow description information of the service flow. In this case, indication information #2 can also be information sent only when the application function has enabled redundant transmission of the service flow. If the application function sends indication information #2, it means that the application function has enabled redundant transmission of the service flow. Otherwise, the application function has not enabled redundant transmission of the service flow. In other words, indication information #2 can be converted into indication information #1 during the transmission process, such as converting the identifier of the service flow (such as the flow description information of the service flow) into relevant information of the service flow (the identifier of the QoS flow carrying the service flow). Alternatively, indication information #2 can also be the same information as indication information #1. For example, when the access network device knows the service flow in advance, the indication information #2 may also only include the above-mentioned indication information element. In this case, the indication information #2 is not changed during the transmission process and is directly transmitted to the access network device.

[0136] In method 1, the application function can send indication information #2 to the network through control.

[0137] The application function may send a service flow creation / modification request message, such as a QoS session creation / modification request (Nnef_AFsessionWithQoS_Create / Modify Request) message, to the network (e.g., a network open network element in the network), carrying indication information #2. The indication information #2 may include flow description information of the service flow and, optionally, may also include an indication information element. The network open network element may encapsulate the received indication information #2 into a message sent by the network open network element to the policy control network element, such as a policy authentication creation / modification request (Npcf_PolicyAuthorization_Create / Modify Request) message or any other possible message, and then send the message to the policy control network element. Correspondingly, the policy control network element may encapsulate the received indication information #2 into a message sent by the policy control network element to the session management network element, such as a policy control update notification request (Npcf_SMPolicyContorl_UpdateNotify Request) message or any other possible message, and then send the message to the session management network element. The session management network element can convert indication information #2 into indication information #1 and then send an N1N2 message to the access and mobility management network element. This N1N2 message contains the N2 message, which carries indication information #1. After receiving the N1N2 message, the access and mobility management network element can send an N2 message to the access network device. In return, the access network device receives the N2 message from the access and mobility management network element. In this way, the indication that the application function has enabled redundant transmission of the service flow is transmitted to the access network device by reusing existing control plane signaling, reducing implementation complexity. Alternatively, it can be transmitted to the access network device via newly defined control plane signaling, achieving decoupling from existing signaling and more flexible signaling.

[0138] Method 2: The application function may send indication information #2 to the network through the user.

[0139] The application function can send the data of the service flow to the network (such as the user plane network element in the network), and the data of the service flow can include indication information #2. For example, the user plane network element can be the user plane anchor point of the service flow, and the indication information #2 can be the same as the above-mentioned indication information #1, such as indication information #2 can only include the indication information element. The application function can encapsulate the indication information element into the header of one or more data packets of the service flow, or any possible position of the data packet. Accordingly, the access network device receives the data of the service flow from the user plane network element, and learns from the indication information #2 carried in the data of the service flow that the application function has enabled redundant transmission of the service flow, thereby realizing user plane in-path transmission, which can reduce communication overhead compared to the method of control plane indication.

[0140] S502: The access network device reduces air interface transmission redundancy of the service flow according to the instruction information.

[0141] Air interface transmission redundancy for a service flow can be the redundant data sent over the air interface. For example, if a service flow contains 100 bits of data, the access network device modulates and encodes these 100 bits to obtain 300 bits, and then sends these 300 bits to the terminal over the air interface, then the 200 bits other than the 100 bits are redundant data.

[0142] The air interface transmission redundancy of a service flow can be represented by at least one of the following: the modulation order of the service flow, the code rate of the service flow, or the air interface transmission efficiency of the service flow. The modulation order of the service flow is ranked from low to high as follows: quadrature phase shift keying (QPSK), 16-quadrature amplitude modulation (QAM) or 64QAM. As the modulation order increases, the redundant data generated by the modulation and coding of the service flow can occupy fewer resources, and the air interface transmission redundancy of the service flow is also lower. The code rate of the service flow can gradually increase from 0 to 1, and the less redundant data is generated by the coding, such as a code rate of 0.4 means that the redundant data accounts for 0.6, and a code rate of 0.8 means that the redundant data accounts for 0.2, so the air interface transmission redundancy of the service flow is also lower. The air interface transmission efficiency of the service flow can be characterized by the modulation order of the service flow and / or the code rate of the service flow. For example, the air interface transmission efficiency of a service flow = the modulation order of the service flow * the code rate of the service flow. In this case, the higher the modulation order and / or code rate, the higher the air interface transmission efficiency of the service flow and the lower the air interface transmission redundancy of the service flow. For another example, the air interface transmission efficiency of a service flow = the modulation order of the service flow * the code rate of the service flow / the number of retransmissions of the service flow. The number of retransmissions of a service flow can be the number of times the access network device retransmits the data packets of the service flow. In this case, the lower the number of retransmissions, the larger the value of the air interface transmission efficiency of the service flow can be. The higher the air interface transmission efficiency, the lower the air interface transmission redundancy of the service flow.

[0143] Reducing the air interface transmission redundancy of a service flow can refer to reducing the redundant data that is additionally sent by the service flow over the air interface, and can be achieved by increasing the modulation order of the service flow, increasing the code rate of the service flow, or improving the air interface transmission efficiency of the service flow. That is, the access network device can perform at least one of the following operations on the service flow based on the above-mentioned instruction information: increasing the modulation order of the service flow, increasing the code rate of the service flow, or improving the air interface transmission efficiency of the service flow. According to the above-mentioned relevant introduction, increasing the modulation order of the service flow or increasing the code rate of the service flow can be understood as improving the air interface transmission efficiency of the service flow. In other words, reducing the air interface transmission redundancy of the service flow is to improve the air interface transmission efficiency of the service flow, transmit as few redundant bits as possible, and reduce the possibility of network transmission congestion.

[0144] Specifically, at least one of the above operations can be performed within the valid time of the channel quality indicator (CQI). CQI can be used to indicate the status of the channel carrying the service flow. For example, the service flow is carried by the QoS flow, and the QoS flow is mapped to the DRB on the air interface. The channel can specifically be the channel carrying the DRB, or the channel corresponding to the DRB. For example, the channel can be a physical downlink shared channel (PDSCH) or in future communication systems, it can also be any channel used to transmit data. The embodiments of the present application do not limit its naming.

[0145] The air interface transmission redundancy of a service flow corresponds to the CQI. For example, if the CQI indicates that the channel carrying the service flow is in good condition, the air interface transmission redundancy of the service flow can be reduced based on the CQI to improve transmission efficiency. Conversely, if the CQI indicates that the channel is in poor condition, the air interface transmission redundancy of the service flow can be increased based on the CQI to ensure the success rate of data transmission. Similarly, if the application function performs redundant transmission of the service flow, the air interface transmission redundancy of the service flow also needs to be reduced based on the CQI. In other words, the redundant transmission part is already guaranteed by the application function, and the air interface transmission can reduce redundancy appropriately to improve transmission efficiency.

[0146] For example, the access network device is pre-configured with a correspondence between the same CQI and one or more of different modulation orders, different code rates, or air interface transmission efficiencies, to indicate that the access network device needs to reduce the air interface transmission redundancy of the service flow within the range corresponding to the CQI. The access network device can trigger the terminal to perform channel measurement on the channel carrying the service flow and receive the channel measurement result from the terminal. In this way, the access network device can determine the CQI (denoted as CQI#1) corresponding to the measurement result based on the measurement result, such as the channel state of the PDSCH. During the valid time of the CQI#1, the access network device can reduce the air interface transmission redundancy of the service flow within the range corresponding to the CQI#1.

[0147] For example, an example of the above correspondence relationship can be shown in Table 0 below.

[0148] Table 0

[0149] As shown in Table 0, if the access network device determines the CQI, such as the CQI index is CQI_1, the access network device reduces the air interface transmission redundancy of the service flow, such as adjusting the bit rate of the service flow from 0.3001 to 0.4385, and adjusting the air interface transmission efficiency from 0.6016 to 0.8770, or adjusting the air interface transmission efficiency from 0.6016 to 1.1758. Specifically, the access network device can select according to local resources or load conditions, and the embodiment of the present application is not limited to this.

[0150] If CQI#1 fails, the access network device triggers the terminal to perform channel measurement on the aforementioned channel and receives the channel measurement results from the terminal. Based on the measurement results, the access network device can determine a new CQI (denoted as CQI#2) and adjust the air interface transmission redundancy of the service flow according to this new CQI#2 to ensure transmission efficiency.

[0151] In summary, for certain special service flows, such as XR services, when the application function detects packet loss on the network, it will enable redundant transmission of the service flow. For example, the application function will repeatedly send the service flow's data packets and notify the network, such as the access network equipment, that redundant transmission of the service flow has been enabled. In this way, the access network equipment can use this indication to reduce the air interface transmission redundancy of the service flow. In other words, it can reduce the redundant data sent over the air interface for the service flow, thereby reducing the resources occupied by the service flow during air interface transmission, thereby reducing the possibility of network congestion caused by resource constraints.

[0152] Optionally, in combination with the solution shown in FIG5 , before S501 , the method may further include: the application function sends redundant transmission capability information to the network. Correspondingly, the access network device receives the redundant transmission capability information.

[0153] Redundant transmission capability information indicates whether an application function supports redundant transmission. For example, the redundant transmission capability information is a 1-bit information element, and the values ​​of 0 / 1 indicate whether the application function supports redundant transmission. The application function network element can transmit the redundant transmission capability information to the access network device via the control plane. The specific implementation method is similar to the aforementioned indication information. Please refer to the relevant description of Method 1 above and will not be repeated here.

[0154] For access network equipment, when the redundant transmission capability indicates that the application function supports redundant transmission, the access network equipment will perform reception detection on the indication information used to indicate whether the application function turns on redundant transmission of the service flow. In other words, if the redundant transmission capability indicates that the application function does not support redundant transmission, the access network equipment will not perform reception detection on the indication information to reduce the overhead of the access network equipment.

[0155] The above describes the arrangement process of the communication method provided by the embodiment of the present application in conjunction with Figure 5. The following describes in detail the specific process of the communication method provided by the embodiment of the present application in a specific scenario in conjunction with Figures 6 and 7.

[0156] Scenario 1:

[0157] Figure 6 is a second flow diagram of a communication method provided in an embodiment of the present application. This communication method is applicable, for example, to the aforementioned communication system and involves interactions between the AF (e.g., application function), PCF network elements, SMF network elements, UPF network elements, and RAN equipment (e.g., access network equipment). In scenario 1, if the AF enables redundant transmission of a service flow, the AF can send an indication to the RAN equipment via the control plane.

[0158] Specifically, as shown in FIG6 , the process of the communication method is as follows:

[0159] S601: The AF determines whether to enable redundant transmission of a service flow.

[0160] AF can be a third-party application function outside the core network or an application function within the core network, with no restrictions on this. AF can sense whether packet loss has occurred in the service flow from the network (such as the operator's network), such as sensing the packet loss rate of the service flow. The specific sensing method is not restricted, such as reporting by the UE or RAN equipment.

[0161] AF can determine whether to enable redundant transmission of a service flow based on the packet loss rate of the service flow and the redundancy sensitivity of the service flow.

[0162] The redundancy sensitivity of a service flow can indicate the priority of the AF for enabling redundant transmission of the service flow, or the AF's tolerance for enabling redundant transmission of the service flow. It can also be said to correspond to the priority of the AF for enabling redundant transmission of the service flow, or the AF's tolerance for enabling redundant transmission of the service flow. For example, the higher the redundancy sensitivity of the service flow, the more sensitive the AF is to changes in the transmission status of the service flow (such as packet loss), that is, the higher the possibility of enabling redundant transmission of the service flow. Conversely, the lower the redundancy sensitivity of the service flow, the less sensitive the AF is to changes in the transmission status of the service flow, that is, the higher the possibility of enabling redundant transmission of the service flow. The redundancy sensitivity of the service flow can be pre-configured locally on the AF, or can also be obtained by the AF from other network elements, without specific restrictions.

[0163] For example, redundancy sensitivity may have a corresponding relationship #1 with a packet loss rate threshold. This corresponding relationship #1 may be preconfigured locally on the AF or may be obtained by the AF from other network elements, without limitation. A higher redundancy sensitivity corresponds to a lower packet loss rate threshold. For example, an example of corresponding relationship #1 between redundancy sensitivity and packet loss rate threshold may be shown in Table 1 below.

[0164] Table 1

[0165] It can be seen that the redundancy sensitivity is level 1, level 2, level 3, etc. from low to high. The packet loss rate threshold corresponding to the redundancy sensitivity level 1 is 5%, which means that when the redundancy sensitivity is level 1, the packet loss rate of the service flow is greater than or equal to 5%, and AF turns on redundant transmission of the service flow. The packet loss rate threshold corresponding to the redundancy sensitivity level 2 is 3%, which means that when the redundancy sensitivity is level 2, the packet loss rate of the service flow is greater than or equal to 3%, and AF turns on redundant transmission of the service flow. The packet loss rate threshold corresponding to the redundancy sensitivity level 3 is 1%, which means that when the redundancy sensitivity is level 3, the packet loss rate of the service flow is greater than or equal to 1%, and AF turns on redundant transmission of the service flow, and so on.

[0166] Therefore, the AF can determine the packet loss rate threshold corresponding to the redundancy sensitivity of the service flow in the above correspondence #1. If the packet loss rate of the service flow is greater than or equal to the redundancy sensitivity, the AF determines to enable redundant transmission of the service flow; otherwise, redundant transmission of the service flow is not enabled. If redundant transmission of the service flow is enabled, the AF can repeatedly send data packets of the service flow, such as repeatedly sending the same data packet multiple times, with no specific limit on the number of times.

[0167] It will be appreciated that the AF determining whether to enable redundant transmission of a service flow based on the redundancy sensitivity of the service flow is an example and not limiting. For example, the AF may also determine whether to enable redundant transmission of a service flow based solely on whether the service flow has packet loss. If packet loss occurs in the service flow, the AF determines to enable redundant transmission of the service flow; otherwise, redundant transmission of the service flow is not enabled.

[0168] It can also be understood that the redundancy sensitivity of the business flow is an exemplary expression, which can also be replaced by any possible expression, such as the redundant transmission priority of the business flow, the priority of redundant transmission of the business flow, the priority of enabling redundant transmission of the business flow, the redundant transmission threshold of the business flow, etc. Any information that can be used to characterize the tolerance of AF to enabling redundant transmission of the business flow can be understood as the redundancy sensitivity of the business flow in the embodiment of the present application.

[0169] When the AF determines to start redundant transmission of the service flow, the AF triggers execution of S602.

[0170] S602: The AF sends a QoS session creation request (Nnef_AFsessionWithQoS_Creat Request) message to the NEF network element. The NEF network element receives the QoS session creation request message from the AF.

[0171] The QoS session creation request message may include indication information #1, which may be used to indicate that the AF has enabled redundant transmission of the service flow. Optionally, indication information #1 may also be used to indicate the redundancy of the service flow. The redundancy of the service flow may be used to indicate the extent to which the data packets of the service flow are repeatedly sent by the AF when the AF has enabled redundant transmission of the service flow, specifically, the proportion of the data packets repeatedly sent by the AF in the service flow. For example, indication information #1 may include at least one of the following: flow description information of the service flow, or redundancy. The redundancy may be a proportional value, indicating the proportion of data packets repeatedly sent by the AF, such as 32%. The flow description information and redundancy of the service flow may together indicate the redundancy of the service flow.

[0172] It can be understood that the indication information #1 can also refer to the relevant introduction of the above-mentioned method 1, which will not be repeated here.

[0173] S603: The NEF network element authenticates the AF.

[0174] The NEF network element can authenticate the AF based on the QoS session creation request message to determine whether the AF is trustworthy. For details, please refer to the relevant introduction in Chapter 6 of TS29.522. If the authentication is successful, the NEF network element executes S604, otherwise the process ends.

[0175] S604: The NEF network element sends a policy authentication creation request (Npcf_PolicyAuthorization_Create Request) message to the PCF network element. The PCF network element receives the policy authentication creation request message from the NEF network element.

[0176] The policy authentication creation request message may carry the above-mentioned indication information #1.

[0177] It can be understood that S602-S604 are optional steps. For example, if AF is an application function within the core network, AF may also directly send a policy authorization creation request (Npcf_PolicyAuthorization_Create Request) message carrying the above indication information #1 to the PCF network element.

[0178] S605: The PCF network element sends a policy control update notification request message to the SMF network element. The SMF network element receives the policy control update notification request message from the PCF network element.

[0179] The policy control update notification request message can carry the above-mentioned indication information #1. For example, indication information #1 can be carried in the PCC rules contained in the policy control update notification request message. The PCC rules can be the PCC rules of the service corresponding to the service flow. Specifically, they can be existing PCC rules or newly created PCC rules. There is no limitation on this. In other words, the PCF network element can obtain indication information #1 from the policy authentication creation request message, encapsulate it into the PCC rules of the corresponding service, and then pass the PCC rules to the SMF network element through the policy control update notification request message.

[0180] S606: The SMF network element sends an N4 message to the UPF network element. The UPF network element receives the N4 message from the SMF network element.

[0181] The N4 message can carry the above-mentioned indication information #1. For example, indication information #1 can be carried in the QoS configuration contained in the N4 message. The QoS configuration can be a QoS configuration associated with the service flow. Specifically, it can be an existing QoS configuration or a newly created QoS configuration. There is no limitation on this. In other words, if the UPF network element wants to process at the granularity of the service flow, the SMF network element can obtain indication information #1 from the PCC rule, encapsulate it into the corresponding QoS configuration, and then pass the QoS configuration to the UPF network element through the N4 message.

[0182] Alternatively, the N4 message may also carry indication information #2. Indication information #2 may include at least one of the following: information about the QoS flow that carries the service flow (that is, the relevant information of the above-mentioned service flow, which may specifically be QFI), or redundancy. That is to say, if the UPF network element wants to process based on the granularity of the service flow, the SMF network element may obtain indication information #1 from the PCC rule, convert the flow description information of the service flow in indication information #1 into the QFI of the QoS flow that carries the service flow, and then encapsulate the QFI and redundancy as indication information #2 into the QoS configuration corresponding to the QoS flow, and then pass the QoS configuration to the UPF network element through the N4 message.

[0183] It can be understood that the indication information #2 can also refer to the relevant introduction of the above-mentioned method 1, which will not be repeated here.

[0184] S607, the UPF network element determines the scheduling priority of the service flow according to the redundancy of the service flow.

[0185] The scheduling priority of a service flow can be used to indicate the priority of the data packets of the service flow being lost when packet loss is required. For example, the scheduling priority of a service flow is negatively correlated with the priority of the data packets of the service flow being lost. The higher the scheduling priority of the service flow, the lower the priority of the data packets of the service flow being lost. For example, the higher the scheduling priority of the service flow, the more important the data packets of the service flow are. These data packets need to be scheduled first to ensure transmission, so the probability of them being lost is lower, that is, the lower the priority of the data packets being lost. Conversely, the lower the scheduling priority of the service flow, the higher the priority of the data packets of the service flow being lost, and the higher the probability of being lost.

[0186] For example, redundancy can have a corresponding relationship #2 with scheduling priority. This corresponding relationship #2 can be pre-configured locally in the UPF network element, or can be obtained by the UPF network element from other network elements, without limitation. The higher the redundancy, the higher the corresponding scheduling priority. For example, an example of corresponding relationship #2 between redundancy and scheduling priority can be shown in Table 2 below.

[0187] Table 2

[0188] It can be seen that the scheduling priorities are level 0, level 1, level 2, level 3, etc. from low to high. The redundancy range corresponding to the scheduling priority level 4 is 0%. The redundancy range corresponding to the scheduling priority level 3 is 0%<--≤20%. The redundancy range corresponding to the scheduling priority level 2 is 20%<--≤40%. The redundancy range corresponding to the scheduling priority level 1 is 40%<--≤60%, and so on. It can be seen that the scheduling priority of the service flow without redundant transmission is the highest, and its priority for packet loss is also the lowest. On this basis, the UPF network element can determine that the redundancy of the service flow is in the redundancy range of the above-mentioned correspondence #2, and determine the scheduling priority corresponding to the redundancy range as the scheduling priority of the service flow.

[0189] S608: When the network is in a congested state, the UPF network element determines whether to discard the data packets of the service flow based on the scheduling priority of the service flow.

[0190] The network being congested can be understood as meaning that the network is already congested or is about to be congested, without specific limitations. The UPF network element can determine that the network is congested based on information reported by the RAN device. For details, please refer to the relevant description in "3. Release 18 Network Information Openness" above. The UPF network element can determine whether to perform packet drop processing based on the network congestion status. For example, if the network congestion information reported by the RAN device indicates that there is a 60% probability that the network will be congested, if the threshold probability of network congestion is 40%, then 60% is greater than 40%, and the UPF network element decides to perform packet drop processing. Alternatively, if the network congestion information reported by the RAN device indicates that there is a 30% probability that the network will be congested, if the threshold probability of network congestion is 40%, then 30% is less than 40%, and the UPF network element decides not to perform packet drop processing. For another example, if the RAN device reports that the network is already congested, the UPF network element decides to perform packet drop processing. Alternatively, if the RAN device reports that the network is not congested, the UPF network element decides not to perform packet drop processing.

[0191] If the UPF network element decides to perform packet loss processing, the UPF network element can determine whether to discard the data packets of the service flow based on the relationship between the scheduling priority of the service flow and the scheduling priority of other service flows. For example, taking Table 2 as an example, service flow A and service flow B both have redundant transmission enabled, service flow A's redundancy is 10%, service flow A's scheduling priority is level 3, service flow B's redundancy is 35%, service flow B's scheduling priority is level 2, the UPF network element can preferentially discard the data packets of service flow B. For another example, taking Table 2 as an example, service flow A does not have redundant transmission enabled, service flow B has redundant transmission enabled, service flow A's redundancy is 0%, service flow A's scheduling priority is level 4, service flow B's redundancy is 35%, service flow B's scheduling priority is level 2, the UPF network element can also preferentially discard the data packets of service flow B.

[0192] Additionally, if the redundancy of two service flows is within the same redundancy range, the UPF network element may perform packet loss processing on both service flows, or the UPF network element may preferentially discard the data packets of a service flow with higher redundancy.

[0193] It can be understood that S607-S608 is an example of the UPF network element processing at the granularity of business flow. If the UPF network element processes at the granularity of QoS flow, the business flow in S607-S608 can also be replaced by QoS flow.

[0194] S609: The SMF network element sends a N1N2 transmission (Namf_Communication_N1N2MessageTransfer) message to the AMF network element. The AMF network element receives the N1N2 transmission message from the SMF network element.

[0195] The N1N2 transmission message can carry the above-mentioned indication information #2. That is, similar to S606, the SMF network element can obtain indication information #1 from the PCC rule, encapsulate it into the QoS configuration corresponding to the QoS flow, and then pass the QoS configuration to the AMF network element via the N1N2 transmission message.

[0196] S610: The AMF network element sends an N2 PDU Session Request message to the RAN device. The RAN device receives the N2 PDU Session Request message from the AMF network element.

[0197] The N2 Session Request message can be understood as an N2 message that carries the aforementioned indication #2, specifically the QoS configuration corresponding to the QoS flow. In other words, the AMF network element can obtain the QoS configuration from the N1N2 transmission message and pass it to the RAN device via the N2 Session Request message.

[0198] S611: The RAN device reduces air interface transmission redundancy of the QoS flow according to instruction information #2.

[0199] The specific implementation of S611 is similar to that of the above-mentioned S502, which can be understood by reference and will not be repeated here.

[0200] S612: The RAN device determines the scheduling priority of the QoS flow according to the redundancy of the QoS flow.

[0201] S613: When the network is in a congested state, the RAN device determines whether to discard the data packet of the QoS flow according to the scheduling priority of the QoS flow.

[0202] Among them, the specific implementation of S612-S613 is similar to the above-mentioned S607-S608, which can be understood by reference and will not be repeated here.

[0203] S614: The RAN device determines whether to retransmit the discarded data packets in the QoS flow according to the redundancy of the QoS flow.

[0204] The RAN device can determine whether to retransmit discarded packets in a PDU set based on the granularity of the PDU set in the QoS flow. For example, the redundancy can have a corresponding relationship #3 with the maximum allowed number of packet losses in the PDU set (such as the number of consecutive packet losses or the number of non-consecutive packet losses). This corresponding relationship #3 can be pre-configured locally on the RAN device or obtained by the RAN device from other network elements, without specific restrictions. The higher the redundancy, the higher the corresponding scheduling priority. For example, an example of corresponding relationship #3 can be shown in Table 3 below.

[0205] Table 3

[0206] It can be seen that the redundancy range corresponding to the number of packet losses of 0 is 0%, which means that if redundant transmission is not enabled, if a PDU set is lost, retransmission is required for the lost packets. The redundancy range corresponding to the number of packet losses of 2 is 0%<--≤20%, which means that if redundant transmission is enabled and the redundancy is 0%<--≤20%, if the number of lost PDU sets exceeds 2, retransmission is required for the lost packets, otherwise, no retransmission is performed. The redundancy range corresponding to the number of packet losses of 4 is 20%<--≤40%, which means that if redundant transmission is enabled and the redundancy is 20%<--≤40%, if the number of lost PDU sets exceeds 4, retransmission is required for the lost packets, otherwise, no retransmission is performed. The redundancy range corresponding to the number of packet losses of 6 is 40%<--≤60%, which means that when redundant transmission is enabled and the redundancy is 40%<--≤60%, if the number of packet losses in the PDU set exceeds 6, retransmission is required for the lost packets. Otherwise, retransmission is not performed, and so on.

[0207] In other words, redundancy can be positively correlated with the maximum allowable number of packet losses in the PDU set. If the redundancy is higher, the maximum allowable number of packet losses in the PDU set will be greater, the number of retransmissions performed by the RAN device will be fewer, and the resource overhead required for retransmission will be less.

[0208] Therefore, the RAN device can determine the number of packet losses corresponding to the redundancy of the QoS flow in correspondence #3, and then determine whether the number of packet losses in the PDU set of the QoS flow exceeds the number of packet losses. If so, the RAN device performs retransmission for the packet losses, otherwise, no retransmission is performed.

[0209] It should be understood that the RAN device performing packet loss at the PDU set granularity is merely an example and is not intended to be limiting. For example, if the RAN device determines that the same data packet has been retransmitted N times, where N is an integer greater than 1, and if all N data packets have been lost, the RAN device determines to retransmit the data packet; otherwise, no retransmission is performed.

[0210] It should be understood that S606-S614 are optional. If you want the UPF network element to perceive whether the AF has enabled redundant transmission, execute S606-S608. If you want the RAN device to perceive whether the AF has enabled redundant transmission, execute S609-S614.

[0211] It should be understood that the above description of service flow redundancy is based on a ratio, which is not intended to be limiting. For example, service flow redundancy can also be expressed in levels, such as Level 1, Level 2, or Level 3. The higher the level, the higher the corresponding scheduling priority. The specific implementation principle is similar to the above ratio and can be understood by reference. It will not be further elaborated here.

[0212] In addition, if the AF updates the redundancy of the service flow, the AF can also send the latest redundancy of the service flow to the RAN device / UPF network element, so that the RAN device / UPF network element can determine the scheduling priority based on the latest redundancy and decide whether to perform packet loss processing accordingly. The specific principle is similar to the process of Figure 6 above, which can be used as a reference for understanding and will not be repeated here.

[0213] Scenario 2:

[0214] Figure 7 is a third flow diagram of a communication method provided in an embodiment of the present application. This communication method is applicable, for example, to the aforementioned communication system and involves interaction between the AF (Application Function), UPF network elements, and RAN equipment (Access Network Equipment). In Scenario 2, if the AF enables redundant transmission of a service flow, the AF can send an indication to the RAN equipment via the user plane.

[0215] Specifically, as shown in FIG7 , the process of the communication method is as follows:

[0216] S701: AF determines whether to enable redundant transmission of a service flow.

[0217] S701 may be executed when the session establishment / modification of the service flow is completed. For specific implementation, reference may be made to the relevant introduction of S601 above, which will not be repeated here.

[0218] S702: When redundant transmission of a service flow is enabled, the AF marks data packets that are repeatedly sent in the service flow.

[0219] AF can carry indication information #2 in the data of the service flow, such as carrying indication information #2 in the header of one or more data packets of the service flow (or any possible location). The specific implementation principle can refer to the relevant introduction of the above method 2, which will not be repeated here.

[0220] AF can also add a redundancy indication to the data packets that are repeatedly sent in the business flow to indicate that the data packet is a data packet that is repeatedly sent in the business flow. For example, AF can add a redundancy indication (redundancy flag) to the message header information of the repeatedly sent data packet. The redundancy indication can be a 1-bit field with a value of 1. If the value of this field is 0, it means that the redundancy indication is empty, that is, it means that the data packet is not a repeatedly sent data packet. Of course, the redundancy indication can also be implemented in other ways. For example, the redundancy indication can be the same sequence number or timestamp in the message header information of the data packet, indicating that these data packets are repeatedly sent data packets. For example, the message header information of data packet #1, data packet #2 and data packet #3 has the same sequence number or timestamp, which means that 2 of the 3 data packets are repeatedly sent data packets, or that 1 data packet is repeatedly sent twice.

[0221] S703, the UPF network element determines the redundancy of the service flow.

[0222] The UPF network element determines, based on indication information #2, that the AF has enabled redundant transmission of the service flow.

[0223] The UPF network element can also determine the proportion of data packets repeatedly sent by the AF in the service flow. For example, the UPF network element can identify data packets in the service flow that carry a redundancy flag as data packets repeatedly sent by the AF, thereby determining the proportion of data packets repeatedly sent by the AF in the service flow. For example, if 600 of 1000 data packets in the service flow carry a redundancy flag, the AF determines that the proportion of data packets repeatedly sent by the AF in the service flow is 60%.

[0224] The UPF network element can determine the redundancy of the service flow based on the proportion of data packets repeatedly sent by the AF in the service flow, such as determining the proportion of data packets repeatedly sent by the AF in the service flow as the redundancy of the service flow, or determining the redundancy of the service flow based on the proportion of data packets repeatedly sent by the AF in the service flow. At this time, the redundancy of the service flow can be a level. The greater the proportion of data packets repeatedly sent by the AF in the service flow, the higher the corresponding redundancy level. The specific implementation principle can be understood by referring to the introduction of Figure 6 above, and will not be repeated here.

[0225] S704, the UPF network element determines the scheduling priority of the service flow according to the redundancy of the service flow.

[0226] S705: When the network is in a congested state, the UPF network element determines whether to discard the data packets of the service flow based on the scheduling priority of the service flow.

[0227] Among them, the specific implementation of S704-S705 can refer to the relevant introduction of S607-S608 above, which will not be repeated here.

[0228] S706: The RAN device reduces air interface transmission redundancy of the QoS flow according to instruction information #2.

[0229] The specific implementation of S706 is similar to that of the above S502, which can be understood by reference and will not be repeated here.

[0230] S707: The RAN device determines the redundancy of the QoS flow.

[0231] S708: The RAN device determines the scheduling priority of the QoS flow according to the redundancy of the QoS flow.

[0232] S709 : When the network is in a congested state, the RAN device determines whether to discard the data packet of the QoS flow according to the scheduling priority of the QoS flow.

[0233] S710: The RAN device determines whether to retransmit discarded data packets in the QoS flow according to the redundancy of the QoS flow.

[0234] Among them, the specific implementation of S707-S710 can refer to the relevant introduction of the above S611-S613, which will not be repeated here.

[0235] It should be understood that S703-S710 are optional. If you want the UPF network element to perceive whether the AF has enabled redundant transmission, execute S703-S705. If you want the RAN device to perceive whether the AF has enabled redundant transmission, execute S706-S710.

[0236] It will be appreciated that the processes illustrated in Figures 6 and 7 above are based on the example of the AF enabling redundant transmission of a service flow, and are not intended to be limiting. The AF may also transmit the redundancy sensitivity of the service flow to the RAN device / UPF network element via control plane signaling. The specific implementation is similar to the delivery of indication information #2 described above, and can be understood with reference thereto, and will not be further described. The RAN device / UPF network element may determine the scheduling priority of the service flow based on the redundancy sensitivity of the service flow.

[0237] The redundancy sensitivity of a service flow is negatively correlated with its scheduling priority. That is, the higher the redundancy sensitivity of a service flow, the easier it is for the AF to enable redundant transmission for that service flow. Therefore, the scheduling priority of that service flow needs to be lowered to reduce the priority of packet loss for that service flow and to minimize the risk of AF enabling redundant transmission for that service flow due to packet loss. For example, taking Tables 1 and 3 above as an example, the redundancy sensitivity of service flow #1 is level 1, and the corresponding scheduling priority for service flow #1 is level 4. The redundancy sensitivity of service flow #2 is level 2, and the corresponding scheduling priority for service flow #2 is level 3. If network congestion requires packet loss, and both service flow #1 and service flow #2 do not have redundant transmission enabled, the RAN device / UPF network element can preferentially discard the data packets of service flow #2.

[0238] Figure 8 is a fourth flow chart of a communication method provided in an embodiment of the present application. This communication method is applicable to the above communication system and mainly involves the interaction between user plane network elements and application functions.

[0239] As shown in Figure 8, the process of the communication method is as follows:

[0240] S801, the application function receives transmission status information from the network.

[0241] The network may be a network that carries business flows. For details, please refer to the relevant introduction of the network in FIG. 5 above, which will not be described in detail.

[0242] The transmission status information can be used to indicate the redundancy of the air interface transmission of the service flow of the application function. For example, the transmission status information includes at least one of the following items of the service flow transmitted on the air interface: the service flow bit rate or the air interface transmission efficiency of the service flow. For details, please refer to the relevant description in Figure 5 above and will not be repeated here.

[0243] The transmission status information may also be information determined within the validity period of the CQI. The CQI is used to indicate the status of the channel carrying the service flow, so as to avoid the situation where the redundant transmission of the service flow through the air interface does not match the status of the channel indicated by the CQI, causing the application function to start redundant transmission of the service flow when it should not, thereby causing network congestion or aggravating network congestion. For example, the access network device is configured with a correspondence between different CQI indices and different code rates and air interface transmission efficiencies. The access network device can trigger the terminal to perform channel measurement on the channel carrying the service flow and receive the measurement result of the channel from the terminal. In this way, the access network device can determine the CQI (denoted as CQI#3) corresponding to the measurement result based on the measurement result, such as the channel status of the PDSCH. The access network device also determines the code rate and / or air interface transmission efficiency of the service flow corresponding to CQI#3 based on the correspondence, that is, the transmission status information corresponding to CQI#3.

[0244] The access network device can send transmission status information to the application function.

[0245] In one possible approach, the access network device can control the application-oriented function to send transmission status information. For example, the access network device can first send the transmission status information and the identifier of the QoS flow carrying the service flow to the user plane network element. The QoS flow identifier corresponds to the transmission status information, indicating that the transmission status information represents the transmission status of the service flow corresponding to the QoS flow. The user plane network element sends the transmission status information to the session management network element. Optionally, the user plane network element can also convert the QoS flow identifier into service flow information, such as the service flow flow description information, and then send the transmission status information and service flow information to the session management network element. The session management network element then exposes the transmission status information and service flow description information to the application function via the network exposure network element. Accordingly, the application function can receive the transmission status information and service flow description information from the network exposure network element, thereby understanding the transmission status of the service flow on the air interface. During this process, the transmission status information, QoS flow identifier, and service flow information can be carried in Nx messages exchanged between network elements. Nx messages can be existing messages, or in future communication systems, Nx messages can be carried in newly defined messages, without limitation.

[0246] In another possible approach, the access network device can send transmission status information to the application function via the user plane. For example, the access network device can carry the transmission status information in the uplink data of the service flow sent by the terminal to the application function, such as in the header of one or more uplink data packets of the service flow (or any other possible location). In this way, the transmission status information can be transmitted from the user plane network element to the application function along with the uplink data of the service flow. Accordingly, the application function can receive the transmission status information from the user plane network element.

[0247] Optionally, the access network device or user-plane network element can also release the network congestion status information of the service flow to the application function through the L4S mechanism. The specific implementation principle can be referred to the relevant introduction of "3. R18 Network Information Openness" above, which will not be repeated here.

[0248] S802: The application function determines whether to enable redundant transmission of the service flow based on the transmission status information.

[0249] Among them, redundant transmission of business flows refers to the application function repeatedly sending data packets of business flows to the network. The specific implementation principle can also refer to the relevant introduction in Figure 5 above, which will not be repeated here.

[0250] The application function can determine the priority of redundant transmission of the service flow based on the transmission status information, and determine whether to enable redundant transmission of the service flow based on the priority of redundant transmission of the service flow. Among them, the priority of redundant transmission of the service flow can also be understood as the redundancy sensitivity of the above-mentioned service flow. For details, please refer to the relevant introduction of Figure 6 above, which will not be repeated here. For example, if the transmission status information indicates that the redundancy level of the air interface transmission of the service flow is higher, the priority of redundant transmission of the service flow is lower, or the redundancy sensitivity of the service flow is lower, that is, the application function will not easily enable redundant transmission of the service flow, so as to avoid network congestion or aggravation of network congestion due to enabling redundant transmission of the service flow.

[0251] In one possible approach, an application function may preconfigure a correspondence between a threshold range for the transmission status of a service flow and the redundancy sensitivity of the service flow. Based on the threshold range within which the transmission status information falls, the application function may determine the redundancy sensitivity of the service flow corresponding to the transmission status information. For example, an example of this correspondence may be shown in Table 4 below.

[0252] Table 4

[0253] The application function can also pre-configure different redundancy sensitivities of the business flow, or different levels of redundancy sensitivity, and the correspondence between different packet loss rate thresholds of the business flow. When the redundancy sensitivity of the business flow is determined, the application function can determine whether to enable redundant transmission of the business flow based on whether the packet loss rate of the business flow fed back by the terminal reaches the packet loss rate threshold corresponding to the redundancy sensitivity of the business flow. The specific implementation principle can also refer to the relevant introduction of Table 1 above. Of course, if the application function has enabled redundant transmission of the business flow, the application function can also determine whether to disable redundant transmission of the business flow based on the redundancy sensitivity of the business flow. For example, if the packet loss rate of the business flow fed back by the terminal changes to a value that does not reach the packet loss rate threshold corresponding to the redundancy sensitivity of the business flow, the application function can disable redundant transmission of the business flow; otherwise, redundant transmission of the business flow can continue to be enabled.

[0254] In another possible manner, if the application function can also obtain the network congestion information of the service flow, the application function can pre-configure the corresponding relationship between the threshold range of the transmission status of the service flow, the threshold range of the network congestion status of the service flow, and the redundancy sensitivity of the service flow. The application function can determine the redundancy sensitivity of the service flow corresponding to the transmission status information and the network congestion information based on the threshold range of the transmission status information and the threshold range of the network congestion information of the service flow. In this case, if the transmission status information indicates that the redundancy degree of the air interface transmission of the service flow is higher, and the network congestion information of the service flow indicates that the probability of network congestion is greater, then the redundancy sensitivity level of the service flow corresponding to the transmission status information and the network congestion information is lower, and the application function will not easily enable redundant transmission of the service flow, so as to avoid the situation where network congestion or aggravation of network congestion occurs due to enabling redundant transmission of the service flow. For example, an example of this correspondence can be shown in Table 5 below.

[0255] Table 5

[0256] When determining the redundancy sensitivity of the service flow, the application function can also determine whether to enable redundant transmission of the service flow based on whether the packet loss rate of the service flow fed back by the terminal reaches the packet loss rate threshold corresponding to the redundancy sensitivity of the service flow. Alternatively, if the application function has enabled redundant transmission of the service flow, the application function can also determine whether to disable redundant transmission of the service flow based on the redundancy sensitivity of the service flow. The specific implementation principle can also be referred to the relevant introduction in Table 1 above.

[0257] It is understandable that in the event that CQI#3 fails, the access network device can also trigger the terminal to perform channel measurement on the channel and receive the channel measurement results from the terminal. In this way, the access network device can determine a new CQI (denoted as CQI#4) based on the measurement results and report the transmission status information of the service flow according to CQI#4, such as sending the transmission status information corresponding to CQI#4 to the application function. At this time, the application function can determine whether to enable redundant transmission of the service flow based on the transmission status information, or determine whether to disable redundant transmission of the service flow if redundant transmission of the service flow has been enabled, so as to avoid the application function enabling redundant transmission of the service flow when it should not be enabled, causing network congestion or exacerbating network congestion.

[0258] In summary, since application functions can sense the redundancy of air interface transmission of service flows, the greater the redundancy, the greater the likelihood of network congestion, and vice versa. Therefore, application functions can decide whether to enable redundant transmission of service flows based on the redundancy of air interface transmission of service flows. This prevents application functions from enabling redundant transmission of service flows when it should not, which could lead to or exacerbate network congestion.

[0259] The communication method provided in the embodiment of the present application is described in detail above in conjunction with Figures 5 to 8. The communication device for executing the communication method provided in the embodiment of the present application is described in detail below in conjunction with Figures 9 and 10.

[0260] Figure 9 is a structural diagram of a communication device according to an embodiment of the present application. As shown in Figure 9 , the communication device 900 includes a transceiver module 901 and a processing module 902. For ease of illustration, Figure 9 only shows the main components of the communication device.

[0261] The transceiver module 901 is used to perform the transceiver function of the method shown in FIG. 5 to FIG. 8 , and the processing module 902 is used to perform other functions of the method shown in FIG. 5 to FIG. 8 except the transceiver function.

[0262] Optionally, the transceiver module 901 may include a sending module (not shown in FIG9 ) and a receiving module (not shown in FIG9 ). The sending module is used to implement the sending function of the communication device 900 , and the receiving module is used to implement the receiving function of the communication device 900 .

[0263] Optionally, the communication device 900 may further include a storage module (not shown in FIG. 9 ) storing a program or instruction. When the processing module 902 executes the program or instruction, the communication device 900 may perform the functions of the method shown in FIG. 5 to FIG. 8 .

[0264] It can be understood that the communication device 900 can be a terminal or a network device, or a chip (system) or other parts or components that can be set in a terminal or a network device, or a device that includes a terminal or a network device. This application does not limit this.

[0265] In addition, the technical effects of the communication device 900 can refer to the technical effects of the communication method shown in Figures 5 to 8, and will not be repeated here.

[0266] Figure 10 is a second structural diagram of a communication device provided in an embodiment of the present application. Exemplarily, the communication device may be a terminal, or a chip (system) or other component or assembly that can be provided in a terminal. As shown in Figure 10, the communication device 1000 may include a processor 1001. Optionally, the communication device 1000 may further include a memory 1002 and / or a transceiver 1003. The processor 1001 is coupled to the memory 1002 and the transceiver 1003, such as by a communication bus.

[0267] The following is a detailed introduction to the various components of the communication device 1000 in conjunction with FIG10 :

[0268] The processor 1001 is the control center of the communication device 1000 and can be a single processor or a collective term for multiple processing elements. For example, the processor 1001 can be one or more central processing units (CPUs), an application specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of the present application, such as one or more digital signal processors (DSPs) or one or more field programmable gate arrays (FPGAs).

[0269] Optionally, the processor 1001 can execute various functions of the communication device 1000 by running or executing software programs stored in the memory 1002 and calling data stored in the memory 1002, such as executing the communication method shown in Figures 5 to 8 above.

[0270] In a specific implementation, as an embodiment, the processor 1001 may include one or more CPUs, such as CPU0 and CPU1 shown in FIG10 .

[0271] In a specific implementation, as an embodiment, the communication device 1000 may also include multiple processors, such as the processor 1001 and the processor 1004 shown in FIG10 . Each of these processors may be a single-core processor (single-CPU) or a multi-core processor (multi-CPU). The processor herein may refer to one or more devices, circuits, and / or processing cores for processing data (e.g., computer program instructions).

[0272] The memory 1002 is used to store the software program for executing the solution of the present application, and the execution is controlled by the processor 1001. The specific implementation method can refer to the above method embodiment and will not be repeated here.

[0273] Alternatively, the memory 1002 may be a read-only memory (ROM) or other type of static storage device that can store static information and instructions, a random access memory (RAM) or other type of dynamic storage device that can store information and instructions, or an electrically erasable programmable read-only memory (EEPROM), a compact disc read-only memory (CD-ROM) or other optical disc storage, an optical disc storage (including a compact disc, laser disc, optical disc, digital versatile disc, Blu-ray disc, etc.), a magnetic disk storage medium or other magnetic storage device, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and can be accessed by a computer, but is not limited thereto. The memory 1002 may be integrated with the processor 1001 or exist independently and be coupled to the processor 1001 via an interface circuit (not shown in FIG. 10 ) of the communication device 1000. This embodiment of the present application does not specifically limit this.

[0274] Transceiver 1003 is used for communication with other communication devices. For example, if communication device 1000 is a terminal, transceiver 1003 can be used to communicate with a network device or another terminal device. For another example, if communication device 1000 is a network device, transceiver 1003 can be used to communicate with a terminal or another network device.

[0275] Optionally, the transceiver 1003 may include a receiver and a transmitter (not shown separately in FIG10 ), wherein the receiver is used to implement a receiving function, and the transmitter is used to implement a sending function.

[0276] Optionally, the transceiver 1003 may be integrated with the processor 1001 or exist independently and be coupled to the processor 1001 through an interface circuit (not shown in FIG. 10 ) of the communication device 1000 . This embodiment of the present application does not specifically limit this.

[0277] It is understandable that the structure of the communication device 1000 shown in FIG10 does not constitute a limitation on the communication device, and an actual communication device may include more or fewer components than shown in the figure, or combine certain components, or arrange the components differently.

[0278] In addition, the technical effects of the communication device 1000 can refer to the technical effects of the methods described in the above method embodiments, and will not be repeated here.

[0279] It should be understood that the processor in the embodiments of the present application may be a central processing unit (CPU), and the processor may also be other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor, etc.

[0280] It should also be understood that the memory in the embodiments of the present application may be a volatile memory or a non-volatile memory, or may include both volatile and non-volatile memories. Among them, the non-volatile memory may be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or a flash memory. The volatile memory may be a random access memory (RAM), which is used as an external cache. By way of example and not limitation, many forms of random access memory (RAM) are available, such as static RAM (SRAM), dynamic random access memory (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), and direct rambus RAM (DR RAM).

[0281] The above embodiments can be implemented in whole or in part by software, hardware (such as circuits), firmware or any other combination. When implemented using software, the above embodiments can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions or computer programs. When the computer instructions or computer program are loaded or executed on a computer, the process or function described in the embodiment of the present application is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions can be transmitted from one website, computer, server or data center to another website, computer, server or data center via a wired (such as infrared, wireless, microwave, etc.) method. The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device such as a server or data center that contains one or more available media sets. The available medium can be a magnetic medium (for example, a floppy disk, a hard disk, a tape), an optical medium (for example, a DVD), or a semiconductor medium. The semiconductor medium can be a solid-state drive.

[0282] It should be understood that the term "and / or" as used herein simply describes a relationship between associated objects, indicating that three possible relationships exist. For example, "A and / or B" can represent: A alone, A and B together, or B alone. A and B can be singular or plural. Furthermore, the character " / " as used herein generally indicates an "or" relationship between the associated objects, but it may also indicate an "and / or" relationship. For specific understanding, please refer to the context.

[0283] In this application, "at least one" means one or more, and "plurality" means two or more. "At least one of the following" 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, or c can mean: a, b, c, ab, ac, bc, or abc, where a, b, and c can be single or plural.

[0284] It should be understood that in the various embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0285] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0286] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0287] In the several embodiments provided in this application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are merely schematic. For example, the division of the units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0288] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0289] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0290] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0291] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A communication method, characterized in that, Applied to an access network device, including: The access network device receives indication information, where the indication information is used to indicate that an application function has enabled redundant transmission of a service flow, and the redundant transmission of the service flow means that the application function repeatedly sends data packets of the service flow; The access network device reduces the radio interface transmission redundancy of the service flow according to the indication information.

2. The method according to claim 1, wherein The access network device receives indication information, including; The access network device receives an N2 message from an access and mobility management network element, where the N2 message includes the indication information.

3. The method according to claim 1, characterized in that, The access network device receives indication information, including; The access network device receives data of the service flow from a user plane network element, where the data of the service flow includes the indication information.

4. The method according to any one of claims 1-3, characterized in that, The access network device reduces the radio interface transmission redundancy of the service flow according to the indication information, including: The access network device performs at least one of the following operations on the service flow according to the indication information: increasing the modulation order of the service flow, increasing the coding rate of the service flow, or increasing the radio interface transmission efficiency of the service flow.

5. The method according to claim 4, characterized in that, The at least one operation is performed within the valid time of a channel quality indicator (CQI), and the CQI is used to indicate the state of the channel carrying the service flow.

6. The method according to any one of claims 1-5, characterized in that, Before the access network device receives the indication information, the method further includes: The access network device receives redundant transmission capability information, and the redundant transmission capability information is used to indicate whether the application function supports redundant transmission.

7. The method according to claim 6, wherein When the redundant transmission capability indicates that the application function supports redundant transmission, the access network device expects to receive information for indicating that the application function enables redundant transmission.

8. The method according to any one of claims 1 to 7, characterized in that, The method further includes: The access network device sends transmission status information to the application function, and the transmission status information is used to indicate the redundancy situation of the radio interface transmission of the service flow.

9. The method according to claim 8, wherein The transmission status information includes at least one of the following of the service flow transmitted over the radio interface: the modulation order of the service flow, the coding rate of the service flow, or the radio interface transmission efficiency of the service flow.

10. The method according to claim 9, wherein The transmission status information is information determined within the valid time of the CQI, and the CQI is used to indicate the state of the channel carrying the service flow.

11. The method according to claim 5 or 10, characterized in that, The method further includes: When the CQI fails, the access network device triggers the terminal to perform channel measurement on the channel; The access network device receives the measurement result of the channel from the terminal.

12. A communication method, characterized in that, Applied to an application function, including: The application function receives transmission status information from the network, and the transmission status information is used to indicate the redundancy situation of the radio interface transmission of the service flow of the application function; The application function determines whether to enable redundant transmission of the service flow according to the transmission status information, where the redundant transmission of the service flow means that the application function repeatedly sends data packets of the service flow to the network.

13. The method according to claim 12, wherein: The transmission status information includes at least one of the following of the service flow transmitted over the radio interface: the modulation order of the service flow, the coding rate of the service flow, or the radio interface transmission efficiency of the service flow.

14. The method according to claim 12 or 13, characterized in that, The application function determines whether to enable redundant transmission of the service flow according to the transmission status information, including: The application function determines the priority of the redundant transmission of the service flow according to the transmission status information; The application function determines whether to enable the redundant transmission of the service flow according to the priority of the redundant transmission of the service flow.

15. The method according to any one of claims 12 - 14, characterized in that, The method further includes: The application function sends indication information to the network, where the indication information is used to indicate that the application function has enabled the redundant transmission of the service flow.

16. The method according to claim 15, characterized in that, The application function sending the indication information to the network includes: The application function sends a service flow creation / modification request message to the network, and the service flow creation / modification request message includes the indication information.

17. The method according to claim 15, wherein The application function sending the indication information to the network includes: The application function sends the service flow data to the user plane network element in the network, and the data of the service flow includes the indication information.

18. The method according to any one of claims 12-17, characterized in that, The method further includes: The application function sends redundant transmission capability information to the network, where the redundant transmission capability information is used to indicate whether the application function supports redundant transmission.

19. A communication device, characterized in that, The device includes a module for performing the method according to any one of claims 1-18.

20. A communication device, characterized in that, The communication device includes a processor and a memory; the memory is used to store computer instructions, and when the processor executes the instructions, the communication device is caused to perform the method according to any one of claims 1-18.

21. A computer-readable storage medium, characterized in that, The computer-readable storage medium includes a computer program or instruction, and when the computer program or instruction runs on a computer, the computer is caused to perform the method according to any one of claims 1-18.

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