Data transmission method and apparatus

Abstract

The application provides a data transmission method and device. In a relay scenario, a protocol data unit session supporting layered quality of service can be established, thereby reducing the impact on the video effect of the remote device side. The method can include: a remote device sending a first message to a relay device to perform a discovery process or establish a communication connection between the two; wherein the first message includes first information, or the first message includes a relay service code, and the corresponding protocol data unit session parameters include the first information; the relay device establishes a protocol data unit session supporting layered quality of service according to the first information to relay data between the remote device and the network, thereby realizing the transmission of XR services in a relay scenario through the protocol data unit session.

Description

Technical Field

[0001] This application relates to the field of communication technology, and in particular to a data transmission method and apparatus. Background Technology

[0002] Extended reality (XR) refers to an interactive environment combining real and virtual elements, created through computer technology and wearable devices. It's a collective term for various forms including augmented reality (AR), virtual reality (VR), and mixed reality (MR). The fusion of these three visual interaction technologies achieves an immersive experience that seamlessly transitions between the virtual and real worlds. XR and other media services are characterized by bursty data transmission. When base stations cannot guarantee data transmission, such as during network congestion, they may randomly drop one or more data packets from a received set to alleviate congestion. If the randomly dropped data packets are of high importance, it can cause prolonged buffering and affect video quality.

[0003] In relay scenarios, remote user equipment (UE) transmits data through relay UEs. For example, for uplink, the relay UE receives uplink data packets from the remote UE and sends them to the service server via the connection between the relay UE and the network; for downlink, the relay UE receives downlink data packets from the service server and sends them to the remote UE. For XR service transmission in relay scenarios, minimizing the impact on the video quality at the remote UE is a critical technical problem that needs to be solved. Summary of the Invention

[0004] This application provides a data transmission method and apparatus that, in a relay scenario, can establish a protocol data unit session that supports hierarchical quality of service, thereby reducing the impact on the video quality of the remote device.

[0005] In a first aspect, this application provides a data transmission method, which can be executed by a relay device or a module within the relay device. The method may include: the relay device receiving a first message from a remote device, the first message being used to discover the remote device or request to establish a communication connection with the relay device; wherein the first message includes a relay service code, and the protocol data unit session parameters corresponding to the relay service code include first information; or, the first message includes the first information; the first information is used to establish a protocol data unit session supporting hierarchical quality of service, the protocol data unit session being used to relay data from the remote device; the relay device transmitting data from the remote device through the protocol data unit session.

[0006] It is evident that the relay device can establish a protocol data unit session based on the first information and hierarchical quality of service. By transmitting XR services in the relay scenario through this protocol data unit session, the impact on the video effect on the remote device side can be reduced.

[0007] In a first possible implementation of the first aspect, before receiving the first message from the remote device, the relay device receives configuration information from the first network device. The configuration information includes the aforementioned relay service code and the protocol data unit session parameters corresponding to the aforementioned relay service code. The protocol data unit session parameters include first information so that the relay device can perform a discovery process with the remote device based on the relay service code.

[0008] In conjunction with the first aspect or the first possible implementation of the first aspect, in the second possible implementation of the first aspect, after establishing the aforementioned protocol data unit session, the relay device sends a second message to the remote device. The second message is used to determine a first association relationship between uplink data packets and a first-class quality of service (QoS) flow, where the first-class QoS flow is used for data transmission between the relay device and the remote device. It is understood that the first association relationship can represent the association relationship between uplink data packets of different importance and first-class QoS flows of different QoS levels. For example, high-importance uplink data packets can be associated with a first-class QoS flow of high QoS, and low-importance uplink data packets can be associated with a first-class QoS flow of low QoS, so that the remote device can map uplink data packets of different importance to first-class QoS flows of different QoS levels. Through the first association relationship, hierarchical transmission between the remote device and the relay device can be achieved, thereby prioritizing the transmission of first-class QoS flows mapped to high QoS when resources are limited between the two.

[0009] Optionally, the second message includes a tiered quality of service rule, which is used to determine a first association between uplink data packets and the first type of quality of service flow.

[0010] In conjunction with the first aspect or the first possible implementation of the first aspect, in the third possible implementation of the first aspect, when establishing the aforementioned Protocol Data Unit (PDU) session, the relay device sends a request message to the second network device for establishing the aforementioned PDU session. This request message includes first information to instruct the establishment of a PDU session supporting Layered Quality of Service (Tier QoS), thereby relaying data from the remote device. Alternatively, when establishing the aforementioned PDU session, the relay device sends both a request message and the first information to the second network device to instruct the establishment of a PDU session supporting Tier QoS, thereby relaying data from the remote device.

[0011] Optionally, during the establishment of the aforementioned protocol data unit session, the second network device may generate the aforementioned first association relationship and send the first association relationship to the relay device. Upon receiving the first association relationship, the relay device may forward it to the remote device.

[0012] In a fourth possible implementation of the first aspect, combining any one of the first to third possible implementations of the first aspect, the relay device, upon establishing the aforementioned protocol data unit session, establishes multiple first-type quality of service flows with association relationships, establishes multiple second-type quality of service flows with association relationships, and determines a second association relationship between the multiple first-type quality of service flows and the multiple second-type quality of service flows. The second-type quality of service flows are associated with the aforementioned protocol data unit session and are used for data transmission between the relay device and the third network device. The second association relationship is used to associate the first-type quality of service flows with the second-type quality of service flows so that the relay device can transmit uplink data packets from the remote device to the third network device.

[0013] Optionally, the second association is an uplink quality of service rule used to map uplink data packets carried on the first type of quality of service flow to the second type of quality of service flow.

[0014] In conjunction with the fourth possible implementation of the first aspect, in the fifth possible implementation of the first aspect, for uplink transmission: the relay device receives the first uplink data packet from the remote device through the quality of service stream identified by the first stream identifier, maps the first uplink data packet to the first quality of service stream among multiple second-class quality of service streams according to the aforementioned second association relationship, and sends the first uplink data packet to the third network device through the first quality of service stream, thereby realizing the relay device relaying uplink data packets.

[0015] The first flow identifier is used to identify the quality of service flow carrying the first uplink data packet among multiple first-class quality of service flows, and the second association relationship includes the association relationship between the first quality of service flow and the quality of service flow identified by the first flow identifier.

[0016] Through the second association, the relay device can map the first type of service quality flow with high importance to the second type of service quality flow with high service quality, so as to avoid the loss of important data.

[0017] In conjunction with the fourth possible implementation of the first aspect, in the sixth possible implementation of the first aspect, the relay device, in the case of establishing multiple first-type quality of service flows with association and multiple second-type quality of service flows with association, further determines a third association relationship between the multiple first-type quality of service flows and the multiple second-type quality of service flows. The third association relationship is used to associate the first-type quality of service flows with the second-type quality of service flows so that the relay device can transmit downlink data packets from the third network device to the remote device.

[0018] Optionally, the third association is a downlink quality of service rule used to map downlink data packets carried on a second-class quality of service flow to a first-class quality of service flow.

[0019] In conjunction with the sixth possible implementation of the first aspect, in the seventh possible implementation of the first aspect, for downlink transmission: the relay device receives a first downlink data packet from the third network device through the quality of service stream identified by the second stream identifier, maps the first downlink data packet to a second quality of service stream among multiple first-class quality of service streams according to the third association relationship, and sends the first downlink data packet to the remote device through the second quality of service stream, thereby realizing the relay device relaying downlink data packets.

[0020] The second flow identifier is used to identify the quality of service flow carrying the first downlink data packet in a plurality of second-class quality of service flows; the third association includes the association between the second quality of service flow and the quality of service flow identified by the second flow identifier.

[0021] Through the third association, the relay device can map the high-importance second-class service quality flow to the high-quality first-class service flow to avoid the loss of important data.

[0022] In conjunction with the seventh possible implementation of the first aspect, in the eighth possible implementation of the first aspect, when resources are limited between the remote device and the relay device, if the priority of the second quality of service stream is lower than a threshold, the relay device discards the second downlink data packets mapped to the second quality of service stream. Once resources between the remote device and the relay device are limited, downlink data packets mapped to the second type of quality of service stream with low quality of service can be discarded first to ensure the transmission of the second type of quality of service stream with high quality of service, thereby reducing the impact on video quality.

[0023] In conjunction with the fourth possible implementation of the first aspect, in the ninth possible implementation of the first aspect, the remote device can trigger the relay device to establish multiple Class I Quality of Service (QoS) flows with an association relationship. The relay device receives a first connection message from the remote device and establishes multiple Class I QoS flows with an association relationship based on the first connection message. The first connection message may also indicate the association relationship between the multiple Class I QoS flows, so that the relay device can establish multiple Class I QoS flows with an association relationship based on the association relationship.

[0024] In conjunction with the fourth possible implementation of the first aspect, in the tenth possible implementation of the first aspect, the network side can trigger the relay device to establish multiple Type I Quality of Service flows with association. The relay device receives a Protocol Data Unit Session Modification message from the second network device, which includes the identification information of the remote device, and establishes multiple Type I Quality of Service flows with association with the remote device according to the Protocol Data Unit Session Modification message.

[0025] In conjunction with the tenth possible implementation of the first aspect, in the eleventh possible implementation of the first aspect, when the relay device is triggered on the network side to establish multiple first-type quality of service flows with an association relationship, the relay device can update the previously determined second and / or third association relationships, so that the relay device can dynamically adjust the association relationship between the first-type quality of service flows and the second-type quality of service flows, thereby flexibly utilizing network resources.

[0026] In conjunction with the tenth possible implementation of the first aspect, in the twelfth possible implementation of the first aspect, when the network side triggers the relay device to establish multiple Class I Quality of Service flows with an association, the relay device can inform the remote device of the association relationship between the multiple Class I Quality of Service flows. The relay device sends a second connection message to the remote device, the second connection message indicating the association relationship between the multiple Class I Quality of Service flows, so that the remote device can map uplink data packets to the corresponding Class I Quality of Service flows according to the association relationship and the first association relationship.

[0027] Secondly, this application provides a data transmission method, which can be executed by a remote device or a module within a remote device. The method may include: the remote device sending a first message to a relay device, the first message being used to discover the remote device or request to establish a communication connection with the relay device; wherein the first message includes a relay service code, and the protocol data unit session parameters corresponding to the relay service code include first information; or, the first message includes first information; the first information is used to establish a protocol data unit session supporting hierarchical quality of service, the protocol data unit session being used to relay data from the remote device.

[0028] As can be seen, by sending the first information to the relay device, the remote device enables the relay device to establish a protocol data unit session based on hierarchical quality of service. The transmission of XR services in the relay scenario through this protocol data unit session can reduce the impact on the video quality on the remote device side.

[0029] In a first possible implementation of the second aspect, before sending a first message to the relay device, the remote device receives configuration information from the first network device. This configuration information includes the aforementioned relay service code and the protocol data unit session parameters corresponding to the relay service code. The protocol data unit session parameters include first information so that the remote device can perform a discovery process with the relay device based on the relay service code.

[0030] In a second possible implementation of the second aspect, in conjunction with the second aspect or the first possible implementation of the second aspect, after sending the first message, the remote device receives a second message from the relay device. The second message is used to determine a first association between uplink data packets and a first-class quality of service (QoS) flow, where the first-class QoS flow is used for data transmission between the relay device and the remote device. It is understood that the first association can represent the association between uplink data packets of different importance and first-class QoS flows of different QoS levels. For example, high-importance uplink data packets can be associated with a high-QoS first-class QoS flow, and low-importance uplink data packets can be associated with a low-QoS first-class QoS flow, so that the remote device can map uplink data packets of different importance to first-class QoS flows of different QoS levels. Through the first association, hierarchical transmission between the remote device and the relay device can be achieved, thus prioritizing transmission of first-class QoS flows mapped to high QoS when resources are limited between the two.

[0031] In conjunction with the second possible implementation of the second aspect, in the third possible implementation of the second aspect, when the remote device sends the first uplink data packet, it determines that the first uplink data packet corresponds to a first flow identifier based on the attribute information of the first uplink data packet and in combination with the first association relationship and the association relationship between multiple first-class quality of service flows. The remote device maps the first uplink data packet to the first-class quality of service flow identified by the first flow identifier, and sends the first uplink data packet to the relay device through the first-class quality of service flow identified by the first flow identifier, thereby sending the uplink data packet to the relay device based on the hierarchical transmission mechanism between the remote device and the relay device.

[0032] The attribute information includes one or more of the following: application-specific identifier, triple, and quintuple. The application-specific identifier is used to identify media services such as XR, and the triple or quintuple is used to identify whether the data packet is for media services such as XR.

[0033] In conjunction with the third possible implementation of the second aspect, in the fourth possible implementation of the second aspect, the association relationship between the aforementioned multiple Type I Quality of Service flows can be determined by the remote device. After the remote device determines the relationship, it can send it to the relay device so that the relay device can establish multiple Type I Quality of Service flows with the association relationship based on the association relationship. For example, the remote device sends a first connection message to the relay device. The first connection message is used to request the establishment of multiple Type I Quality of Service flows with the association relationship, and the first connection message includes the association relationship between the multiple Type I Quality of Service flows.

[0034] In conjunction with the third possible implementation of the second aspect, in the fifth possible implementation of the second aspect, the association relationship between the aforementioned multiple first-type quality of service flows may originate from a relay device, which determines the association relationship and sends it to the remote device. For example, the remote device receives a second connection message from the relay device, the second connection message including the association relationship between the multiple first-type quality of service flows.

[0035] In conjunction with the third possible implementation of the second aspect, and in the sixth possible implementation of the second aspect, when resources are limited between the remote device and the relay device, if the priority of the service quality flow identified by the first flow identifier is lower than a threshold, then the relay device discards the second uplink data packet mapped to the service quality flow identified by the first flow identifier. Once resources between the remote device and the relay device are limited, uplink data packets mapped to the first type of service quality flow with low service quality can be discarded firstly to ensure the transmission of the first type of service quality flow with high service quality.

[0036] Thirdly, this application provides a communication device, which can be a relay device, a device within a relay device, or a device compatible with a relay device. The communication device can also be a chip system. The communication device can execute the method described in the first aspect. The functions of the communication device can be implemented in hardware or by hardware executing corresponding software. The hardware or software includes one or more units or modules corresponding to the above functions.

[0037] The unit or module may be software and / or hardware. The operations performed by the communication device and its beneficial effects can be found in the description and effects described in the first aspect above.

[0038] Fourthly, this application provides a communication device, which can be a remote device, a device within a remote device, or a device compatible with a remote device. The communication device can also be a chip system. The communication device can execute the method described in the second aspect. The functions of the communication device can be implemented in hardware or by hardware executing corresponding software. The hardware or software includes one or more units or modules corresponding to the above functions. The unit or module can be software and / or hardware. The operations performed by the communication device and its beneficial effects can be found in the method described in the second aspect above.

[0039] Fifthly, this application provides a communication device, which includes a processor and an interface circuit. The interface circuit is used to receive signals from other communication devices outside the communication device and transmit them to the processor, or to send signals from the processor to other communication devices outside the communication device. The processor is used to implement the method described in either the first or second aspect through logic circuits or execution code instructions.

[0040] In a sixth aspect, this application provides a computer-readable storage medium storing instructions that, when executed by a communication device, implement the method described in either the first or second aspect.

[0041] In a seventh aspect, this application provides a computer program product including instructions that, when read and executed by a communication device, cause the communication device to perform a method as described in either the first or second aspect.

[0042] Eighthly, this application provides a communication system including at least one communication device for performing the method described in the first aspect above, and at least one communication device for performing the method described in the second aspect above. Attached Figure Description

[0043] Figure 1 This is a schematic diagram of a system architecture applying this application;

[0044] Figure 2 This is a schematic diagram of a 5G system;

[0045] Figure 3 This is a schematic diagram of the relay process;

[0046] Figure 4 This is a flowchart illustrating the data transmission method provided in this application;

[0047] Figure 5 This is an example diagram of uplink transmission provided in this application;

[0048] Figure 6 This is an example diagram of downlink transmission provided in this application;

[0049] Figure 7 This is a flowchart illustrating the data transmission method provided in Embodiment 1 of this application;

[0050] Figure 7-1 This is a schematic diagram of the process for a relay UE to establish a PDU session that supports LQoS;

[0051] Figure 7-2 This is a diagram illustrating the PDU session modification process;

[0052] Figure 8 This is a flowchart illustrating the data transmission method provided in Embodiment 2 of this application;

[0053] Figure 9 This is a flowchart illustrating the data transmission method provided in Embodiment 3 of this application;

[0054] Figure 10 This is a schematic diagram illustrating a form of communication between a relay device and a remote device.

[0055] Figure 11 This is a schematic diagram of the structure of a communication device provided in an embodiment of this application;

[0056] Figure 12 This is a schematic diagram of another communication device provided in an embodiment of this application. Detailed Implementation

[0057] The terms "first" and "second," etc., used in the specification, claims, and drawings of this application are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or apparatuses.

[0058] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0059] In this application, "at least one (item)" refers to one or more, "more than one" refers to two or more, "at least two (items)" refers to two or three or more, and "and / or" is used to describe the correspondence between related objects, indicating that there can be three relationships. For example, "A and / or B" can mean: only A exists, only B exists, and both A and B exist simultaneously, where A and B can be singular or plural. The character " / " generally indicates that the related objects before and after are in an "or" relationship. "At least one (item) of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one (item) of a, b, or c can mean: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, and c can be single or multiple.

[0060] To better understand this application, the system architecture applying this application is described below:

[0061] Please see Figure 1 This is a schematic diagram of a system architecture that applies this application. Figure 1 The system shown is a relay system, which can include a relay system and a communication system. The relay system could be a layer 3 relay system, and the communication system could be a fifth-generation (5G) relay system. th For information on 5G systems (or future communication systems), please refer to [reference needed]. Figure 2 . Figure 1 The system shown may include, but is not limited to, remote devices, relay devices, access network devices, core networks, and data networks (DNs). Among them, remote devices and relay devices may belong to relay systems; relay devices, access network devices, core networks, and data networks may belong to communication systems.

[0062] In a relay system, the terminal device that obtains relay services is called a remote device, and the terminal device that provides relay services is called a relay device. The communication interface between the relay device and the remote device can be called a PC5 port. A remote device can also be described as a remote UE, such as a smart bracelet, virtual reality terminal device (e.g., VR glasses), augmented reality terminal device (e.g., AR glasses), a wireless terminal in telemedicine, a wireless terminal in a smart grid, a wireless terminal in a smart city, a wireless terminal in a smart home, or an in-vehicle terminal in the Internet of Vehicles. A relay device can also be described as a relay UE or a layer-3 UE (i.e., layer-3 UE-to-network relay) used for network relay, such as a smartphone, customer premises equipment (CPE), a personal computer, a mobile station, a remote station, or an access point (AP).

[0063] In this application, the apparatus for implementing the function of a relay device can be the relay device itself, or it can be any apparatus capable of supporting the relay device in implementing that function, such as a chip system or a combination of devices or components capable of implementing the function of a relay device. This apparatus can be installed in the relay device. The chip system can consist of chips or include chips and other discrete devices. In the technical solutions provided in the embodiments of this application, the relay device is used as an example to describe the technical solutions provided in the embodiments of this application. The same applies to remote devices. For ease of description, the technical solutions provided in the embodiments of this application are described using the terms relay UE and remote UE.

[0064] Access network (RAN) equipment, also known as radio access network (RAN) equipment, is a device that connects terminal devices to a wireless network. It can provide terminal devices with functions such as radio resource management, quality of service (QoS) management, data encryption and compression. The access network can be a device with wireless transceiver capabilities or a chip that can be configured in such a device. This access network device can include, but is not limited to: next-generation node base stations (gNBs) in 5G systems; next-generation evolved Node Bs (ng-eNBs) used to connect to long-term evolution (LTE) base stations in the 5G core network; radio network controllers (RNCs); node Bs (NBs); base station controllers (BSCs); base transceiver stations (BTSs); home evolved node Bs (or home node Bs (HNBs)); base band units (BBUs); transmitting and receiving points (TRPs); transmitting points (TPs); small cell equipment (pico); mobile switching centers; or access network equipment in future networks. The communication interface between relay equipment and access network equipment can be called a Uu interface.

[0065] The core network is responsible for maintaining the subscription data of the mobile network and providing terminal devices with functions such as session management, mobility management, policy management, and security authentication. For example... Figure 2As shown, the core network in a 5G system can include the following network elements: user plane function (UPF), authentication server function (AUSF), access and mobility management function (AMF), session management function (SMF), service communication proxy (SCP), network slice selection function (NSSF), network exposure function (NEF), network function repository function (NRF), policy control function (PCF), unified data management (UDM), and application function (AF).

[0066] AMF (Automatic Mobility Management) provides mobility management functions such as user location updates, user network registration, and user handover. It also provides functions like lawful interception, access authorization, and authentication. SMF (Service Provider Management) is primarily responsible for session management in the mobile network, such as session establishment, modification, and release. Specific functions include assigning Internet Protocol (IP) addresses to users and selecting the UPF (User Provider Function) to provide packet forwarding. SCP (Signaling Service Controller) primarily handles signaling forwarding, routing, and load balancing. UPF (User Provider Function) is responsible for forwarding and receiving user data. It can receive user data from the data network and transmit it to the UE (User Equipment) through access network equipment; it can also receive user data from the UE through access network equipment and forward it to the data network. PCF (Programmable Component Function) primarily supports providing a unified policy framework to control network behavior, providing policy rules to control layer network functions, and acquiring user subscription information related to policy decisions. PCF can provide policies to AMF and SMF, such as QoS policies and slice selection policies. AUSF (User Authentication Service Function) is used to perform UE security authentication. NSSF (Network Slice Selection Function) is used to select network slices for the UE. NEF (Network Function Exposure Function) primarily supports the opening of capabilities and events. NRF (Network Function Provider Function) provides storage and selection functions for network function entity information to other network elements. User Data Manager (UDM) is used to store user data, such as subscription data and authentication / authorization data. Application Server (AF) is the server-side component that provides a specific type of service to the user; it can also be called an application server or service server. It can be an AF deployed on the operator's network or a third-party AF.

[0067] A data network (DN) is used to provide services to users. It can be a private network, such as a local area network (LAN); an external network not controlled by the operator, such as the Internet; or a proprietary network jointly deployed by operators, such as a network providing an IP multimedia subsystem (IMS). A user equipment (UE) can access the DN through an established protocol data unit (PDU) session. In 5G systems, the session in which the UE accesses the DN is called a PDU session. As standards evolve, future communication systems may use other names for PDU sessions; this application uses the PDU session as an example.

[0068] Figure 2 Taking 5G as an example, this discussion will illustrate how standards evolve and communication technologies develop. Figure 2 The network elements shown may change. The UPF, PCF, SMF, etc. involved in this application can be replaced with network elements that have the same function as these network elements in future communication systems.

[0069] The relevant technologies or names involved in this application are described below.

[0070] 1. XR services

[0071] In media services such as XR, video data is typically composed of frames, with each frame representing a still image. Frames that make up video data can include I-frames and P-frames. An I-frame represents a keyframe, which can be understood as a complete preservation of the image. Because it contains the entire image, decoding only requires this frame's data. A P-frame represents the difference between this frame and a previous keyframe (such as an I-frame). Decoding requires overlaying the previously cached image with the difference defined in this frame to generate the final image. If I-frame decoding fails, all subsequent P-frames will fail to decode. Typically, an I-frame is followed by several P-frames, resulting in a prolonged period of stuttering.

[0072] 2. Relay Mechanism

[0073] Relay mechanisms, such as Layer 3 relay mechanisms, refer to a relay UE performing network layer (e.g., IP layer) relay for a remote UE. Specifically, for uplink, the remote UE sends uplink IP packets to the relay UE. Upon receiving the uplink IP packet, the relay UE forwards it to the UPF through its connection to the network. For downlink, the UPF sends downlink IP packets to the relay UE. Upon receiving the downlink IP packet, the relay UE forwards it to the remote UE, where the application layer processes the downlink IP packet.

[0074] Please see Figure 3 This is a schematic diagram of the relay process, which may include, but is not limited to, the following steps:

[0075] 101a, Authorization and provisioning for layer-3 UE-to-network relay.

[0076] The network authorizes and provides parameters to the relay UE. During this process, the first network device authorizes the relay UE to provide relay services to the remote UE and provides the relay UE with one or more relay service codes (RSCs), as well as PDU session parameters corresponding to each RSC. The first network device can be a PCF in a 5G system, or a network element with the same function as a PCF in future communications; this application uses a PCF as an example. The PCF sends one or more RSCs, as well as the PDU session parameters corresponding to each RSC, to the relay UE. When the PCF sends these parameters to the relay UE, it may pass through one or more network elements, such as an AMF; that is, the PCF sends the parameters to the AMF, and then the AMF sends them to the relay UE through access network equipment (e.g., a base station).

[0077] RSC can identify a connection service provided by a relay UE to a remote UE, or it can identify connection information that the remote UE is interested in or desires. PDU session parameters may include one or more of the following: PDU session type, data network name (DNN), session and service continuity (SSC) mode, single network slice selection assistance information (S-NSSAI), and access type preference.

[0078] 101b, Authorization and provisioning for remote UE.

[0079] Similar to step 101a, the PCF also authorizes the remote UE to obtain network services through the relay UE and provides the remote UE with one or more RSCs, as well as the PDU session parameters corresponding to each RSC.

[0080] In steps 101a and 101b, the RSC and the corresponding PDU session parameters are used in the discovery process of step 103.

[0081] Optional, 102, Relay UE establishes PDU session.

[0082] 103. The remote UE and the relay UE perform the discovery procedure.

[0083] The discovery process between the remote UE and the relay UE can be implemented through either Mode A or Mode B.

[0084] In Mode A, the relay UE broadcasts an RSC that it can provide for connection services to a remote UE. When the RSC expected by the remote UE matches (e.g., is the same) the RSC broadcast by the relay UE, the remote UE discovers the relay UE and can then proceed to step 104. The number of RSCs broadcast by the relay UE can be one or more.

[0085] In Mode B, the remote UE broadcasts its desired RSC. When the RSC that the relay UE can provide for the connection service to the remote UE matches the RSC broadcast by the remote UE, the relay UE responds to the remote UE, and the remote UE and the relay UE perform the discovery process, thus enabling step 104 to be executed.

[0086] 104. The remote UE establishes a unicast connection with the relay UE.

[0087] The remote UE and the relay UE perform a discovery procedure and establish a unicast connection, i.e., establish a communication connection. Optionally, during or after the execution of step 104, the relay UE may establish a new PDU session. This PDU session can be used for data packets between the relay UPF and the remote UE, enabling the remote UE to obtain network services through the connection between the relay UE and the network. Optionally, this unicast connection is a Layer 2 connection between the remote UE and the relay UE, i.e., the connection establishment request message and connection establishment response message sent between the remote UE and the relay UE carry the source Layer 2 identifier and the target Layer 2 identifier.

[0088] Optional, 105, IP address allocation. For example, a relay UE assigns an IPv4 address or an IPv6 prefix to a remote UE.

[0089] Optionally, 106, the unicast connection established in step 104 can be modified. For example, QoS flows can be added, modified, or deleted on the unicast connection.

[0090] 107. The relay UE sends a remote UE report to the second network device. Correspondingly, the second network device receives the remote UE report from the relay UE.

[0091] The second network device can be an SMF in a 5G system, or a network element with the same function as an SMF in a future communication system. This application takes an SMF as an example. The relay UE sends a remote UE report to the SMF sequentially through the access network equipment and the AMF, or the relay UE sends a remote UE report to the SMF through the AMF.

[0092] The remote UE report may include the remote user identifier (e.g., UE ID) and remote UE information, such as the remote UE's IP address, i.e., the IP address assigned to the remote UE by the relay UE.

[0093] After step 107, the relay UE transmits data packets between the UPF and the remote UE in relay mode.

[0094] In this application, the PDU session parameters corresponding to the RSC configured by the PCF for the relay UE and the remote UE may include first information. This first information is used to establish a PDU session supporting layered quality of service (QoS). This PDU session is used to relay data from the remote UE. Layered QoS can be understood as implementing QoS control through layering. That is, the service data flow of the same application can be transmitted within the network through multiple QoS flows. Different QoS flows have different QoS guarantees, and different QoS flows are used to transmit data of different importance for the application (e.g., one QoS flow transmits I-frame data, another transmits P-frame data; or one QoS flow transmits data within the field of view, another transmits data outside the field of view; these are just examples and do not limit how service data flows are divided in layered QoS). Layered QoS can be represented as layered QoS, or simply LQoS. The name "layered QoS" is for illustrative purposes; other names can also be used, such as associated QoS. The first information can be a parameter, such as the QoS control type. The value of this parameter can indicate the establishment of a PDU session supporting LQoS, or indicate the establishment of a PDU session supporting independent QoS. An independent QoS PDU session is... Figure 3 PDU sessions in the process.

[0095] For example, the correspondence between RSC and PDU session parameters can be represented as: RSC->PDU sessionparameters(PDU session type, DNN, SSC mode, S-NSSAI, access type preference, QoS control type). For instance, RSC1->PDU Session parameters(IPv4, cmnet, SSC mode1, MBB, 3gpp, LQoS) indicates that the QoS control type in the PDU session parameters corresponding to RSC1 is LQoS, used to indicate the establishment of a PDU session supporting LQoS. As another example, RSC2->PDU Session parameters(IPv6, cmnet, SSC mode3 MBB, 3gpp, independent QoS) indicates that the QoS control type in the PDU session parameters corresponding to RSC2 is independent QoS, used to indicate the establishment of a PDU session supporting independent QoS. Alternatively, when the QoS control type value is 1, it indicates the establishment of a PDU session supporting LQoS; when it is 0, it indicates the establishment of a PDU session supporting independent QoS.

[0096] Subsequently, the remote UE and the relay UE perform the discovery process based on the first information indicating LQoS. In mode A, if the relay UE supports LQoS, it can broadcast an RSC (Record Type Function) that includes LQoS in the associated PDU session parameters. In mode B, the remote UE broadcasts an RSC whose corresponding PDU session parameters indicate LQoS, and the relay UE, if it supports LQoS, can respond to the remote UE.

[0097] 3. Type I and Type II Quality of Service Flows

[0098] Quality of Service (QoS) flow, or other names used to describe QoS flow, is a key feature of 5G systems. QoS control is implemented at the granular level of QoS flow. A QoS flow is a granularity of QoS forwarding processing defined by the 5G system. Data mapped to the same QoS flow will receive the same forwarding processing, such as scheduling policies, queuing management policies, and rate shaping policies. Different QoS flows can provide different QoS forwarding processing.

[0099] In this application, the first type of Quality of Service flow is used to transmit data between the relay UE and the remote UE. The relay UE and the remote UE transmit data through the PC5 port, and thus the first type of Quality of Service flow can also be called PC5 QoS flow or QoS flow of the first interface, etc., where the first interface is the PC5 port.

[0100] In this application, the second type of Quality of Service (QoS) flow is used to transmit data between the relay UE and the third network device. The third network device can be a UPF in a 5G system, or a network element with the same function as a UPF in a future communication system; this application uses a UPF as an example. The communication interface between the relay UE and the access network device is the Uu interface. The second type of QoS flow can also be called Uu QoS flow or QoS flow of the second interface, etc., where the second interface is the Uu interface.

[0101] In the following embodiments, the first type of quality of service flow is described as PC5 QoS flow, and the second type of quality of service flow is described as Uu QoS flow.

[0102] This application can be applied to the transmission of XR services in relay scenarios. For example, when VR / AR glasses obtain AR video from an XR server, the VR / AR glasses act as the remote UE, and a smartphone or CPE acts as the relay UE. The VR / AR glasses connect to the network via the smartphone or CPE relay to obtain AR video from the XR server. The smartphone can relay for the VR / AR glasses via a hotspot or other methods. Another example is when an in-vehicle terminal obtains video data from an XR server. The in-vehicle terminal acts as the remote UE, and a smartphone acts as the relay UE. The in-vehicle terminal connects to the network via the smartphone relay to obtain video data from the XR server. In areas with weak signal coverage, such as underground parking lots, tunnels, or corners of rooms, relaying via a relay UE can save power consumption of the remote UE and reduce the impact of weak signal on the remote UE. Here, the XR server refers to the server corresponding to the XR service.

[0103] The data transmission method provided in this application is described below.

[0104] Please see Figure 4 This is a flowchart illustrating the data transmission method provided in this application, which may include, but is not limited to, the following steps:

[0105] 401. The remote UE sends a first message to the relay UE. Correspondingly, the relay UE receives the first message from the remote UE.

[0106] In the first implementation, the first message is used to discover the remote UE. That is, the first message is sent during the discovery process to help the relay UE discover the remote UE so as to establish a communication connection with the remote UE. For example, the first message can be a discovery request message.

[0107] In this approach, the first message may include an RSC, and the PDU session parameters corresponding to the RSC include the first information. Optionally, the first information can be a parameter, such as QoS control type. The value of this parameter can instruct the relay UE to establish a PDU session supporting LQoS, or instruct the relay UE to establish a PDU session supporting independent QoS. An independent QoS PDU session is... Figure 3 The PDU session in the process. Optionally, the first message can be LQoS, directly instructing the relay UE to establish a PDU session supporting LQoS. The first message includes RSC, which will be described in Example 1.

[0108] Alternatively, in this approach, the first message includes first information, which can be an indication, such as LQoS indication information, used to instruct the relay UE to establish a PDU session supporting LQoS. For example, in addition to carrying the RSC expected by the remote UE (whose corresponding PDU session parameters do not include QoS control type), the discovery request message can also carry LQoS indication information.

[0109] In the second implementation, the first message is used to request the establishment of a communication connection with the relay UE. This communication connection can be a unicast connection, which can be initiated by either the remote UE or the relay UE. This application does not limit the initiator of the connection establishment. The first message is executed after the discovery process is completed. The discovery process can be found in [reference needed]. Figure 3 The discovery process is shown. The first message can be a connection request message, such as a Layer 2 link establishment request message or a direct communication request message.

[0110] In this method, the first message may include an RSC, and the PDU session parameters corresponding to the RSC include the first information. The RSC indirectly instructs the relay UE to establish a PDU session that supports LQoS.

[0111] In this approach, the first message includes first information, which can be an indication, such as LQoS indication information, used to instruct the relay UE to establish a PDU session supporting LQoS. For example, when the remote UE determines that the relay service is a media service such as XR, it sends a direct communication request message carrying LQoS indication information to the relay UE. The direct communication request message carrying LQoS indication information will be described in Embodiment 2.

[0112] The aforementioned LQoS-supporting PDU session is a communication connection established between the relay UE and the network. It is used to relay data from the remote UE. The relayed data can be uplink data sent from the remote UE to the network or downlink data sent from the network to the remote UE.

[0113] Optionally, before step 401, the first network device configures and sends configuration information to the remote UE and the relay UE. This configuration information includes an RSC and corresponding PDU session parameters. The PDU session parameters include first information, enabling the remote UE and the relay UE to perform a discovery process based on the RSC corresponding to the PDU session parameters including the first information. The first network device can be a PCF in a 5G system, or a network element with the same function as the PCF in future communications. This application uses the PCF as an example. The PCF sending configuration information to the remote UE or the relay UE can traverse through one or more network elements, such as the AMF; that is, the PCF sends the information to the AMF, and then the AMF sends it through the access network device.

[0114] 402, The relay UE establishes a PDU session supporting LQoS.

[0115] Upon receiving the first message, the relay UE establishes a PDU session supporting LQoS. The process of the relay UE establishing a PDU session supporting LQoS will be described in Example 1.

[0116] When establishing a PDU session supporting LQoS, a relay UE can send a request message to a second network device (such as the SMF in a 5G system, or a network element with the same function as the SMF in a future communication system) to establish the PDU session. The relay UE can send the request message to the SMF through the AMF, or sequentially through the access network device and the AMF. The request message includes first information so that the SMF can configure layered QoS flows for the relay UE's PDU session. Optionally, the SMF can also generate second information based on the first information, which is used to determine the first association between uplink data packets and PC5 QoS flow.

[0117] In another implementation, when a relay UE establishes a PDU session that supports LQoS, it sends first information and a request message for establishing the PDU session to the AMF. The AMF selects an SMF that supports LQoS based on the first information and sends the first information and the request message for establishing the PDU session to the selected SMF. The SMF configures layered QoS flows for the relay UE's PDU session. Optionally, the SMF can also generate second information based on the first information. The second information is used to determine the first association between uplink data packets and PC5QoS flow.

[0118] This application describes the second information as an LQoS rule, which is used to determine the first association between uplink data packets and the PC5QoS flow. The uplink data packet can be an uplink IP packet or an uplink Ethernet packet, etc. In this application, uplink data packets and downlink data packets refer to data packets from media services such as XR.

[0119] Optionally, the LQoS rule is used to determine the primary association between the importance of uplink data packets and the PC5 QoS flow, or described as a mapping relationship between the importance of uplink data packets and the PC5 QoS flow. The LQoS rule can map high-importance uplink data packets to high-QoS PC5 QoS flows and low-importance uplink data packets to low-QoS PC5 QoS flows to ensure the transmission of high-importance data packets. For example, an LQoS rule can be represented as {application identifier, triple / quintuplet, importance level, PC5 QoS flow identifier}, where the application identifier identifies the application of the XR service; the triplet refers to the source IP address, destination IP address, and protocol number of the uplink data packet; the quintuplet refers to the source IP address, destination IP address, protocol number, source port, and destination port of the uplink data packet; and the PC5 QoS flow identifier (PFI) identifies the PC5 QoS flow. For example, {Application 1, Triplet 1, Importance Level 1, PFI 1} means that based on triplet 1 of the uplink data packet of Application 1, the importance level is determined to be 1, and the uplink data packet can be mapped to the PC5 QoS flow identified by PFI 1; {Application 2, Triplet 2, Importance Level 2, PFI 2} means that based on triplet 2 of the uplink data packet of Application 2, the importance level is determined to be 2, and the uplink data packet can be mapped to the PC5 QoS flow identified by PFI 2. It should be noted that high QoS and low QoS are relative concepts. High QoS can refer to a QoS flow with higher QoS guarantee requirements, such as a guaranteed bit rate (GBR) resource guarantee type, or relatively high packet delay budget and packet error rate requirements; low QoS can refer to a QoS flow with relatively lower QoS guarantee requirements, such as a non-guaranteed bit rate (Non-GBR) resource guarantee type, or relatively low packet delay budget and packet error rate requirements. Optionally, LQoS is used to determine the first association between the priority of uplink packets and the PC5 QoS flow, or to describe the mapping relationship between the priority of uplink packets and the PC5 QoS flow. The LQoS rule can map high-priority uplink packets to high-QoS PC5 QoS flows and low-priority uplink packets to low-QoS PC5 QoS flows.

[0120] The SMF sends an accept message for PDU session establishment to the relay UE. Optionally, the accept message for PDU session establishment includes the LQoS rule it generates so that the relay UE can perform step 403. When sending the accept message for PDU session establishment to the relay UE, the SMF may pass through the AMF, or sequentially through the AMF and the access network device.

[0121] 403, the relay UE sends a second message to the remote UE. Correspondingly, the remote UE receives the second message from the relay UE.

[0122] The second message is used to determine the first association between the uplink data packet and the PC5 QoS flow. This can be understood as the second message including the aforementioned LQoS rule. The second message can be a connection response message, such as an L2 link establishment acceptance message or a direct communication acceptance message.

[0123] 404, The relay UE establishes multiple PC5 QoS flows with a relationship, and establishes multiple UuQoS flows with a relationship.

[0124] The establishment of multiple PC5 QoS flows with a relationship between the relay UE and the network can be triggered by the remote UE.

[0125] Multiple PC5 QoS flows with a relationship are used to implement layered transmission between the remote UE and the relay UE, that is, to implement layered transmission on the PC5 interface; multiple Uu QoS flows with a relationship are used to implement layered transmission between the relay UE and the UPF, that is, to implement layered transmission on the Uu interface, specifically for data between the relay remote UE and the UPF.

[0126] The number of PC5 QoS flows and the number of Uu QoS flows can be the same, for example, both being 2, or they can be different, for example, the number of PC5 QoS flows is 3 and the number of Uu QoS flows is 2, or the number of PC5 QoS flows is 1 and the number of Uu QoS flows is 2. The relay UE can determine the number of related PC5 QoS flows based on the number of flows supported by the remote UE. In Examples 1 to 3, 2 PC5 QoS flows and 2 Uu QoS flows are used as examples.

[0127] 405, The relay UE determines a second association relationship and / or a third association relationship between multiple PC5 QoS flows and multiple Uu QoS flows. Here, "determine" can also be described as "generate".

[0128] Step 404 associates multiple PC5 QoS flows and multiple Uu QoS flows, but does not associate PC5 QoS flows with Uu QoS flows. Step 405 will then associate these two flows.

[0129] In this application, a second association between multiple PC5 QoS flows and multiple Uu QoS flows is used to relay UEs for uplink transmission. Specifically, the relay UE maps uplink data packets received from remote UEs via the PC5 QoS flow to the Uu QoS flow, so that the uplink data packets can be sent to the UPF via the Uu QoS flow. The second association can be represented by the association between the identifiers of the PC5 QoS flow and the Uu QoS flow, that is, by the association between the PFI and QFI. For example, the second association between two PC5 QoS flows and two Uu QoS flows can be represented as {(PFI1->QFI1),(PFI2->QFI2)}, where (PFI1->QFI1) indicates that PC5 QoS flow1 identified by PFI1 is associated with Uu QoS flow1 identified by QFI1, and the uplink data packets carried by PC5 QoS flow1 can be mapped to Uu QoS flow1; and (PFI2->QFI2) indicates that PC5 QoS flow2 identified by PFI2 is associated with Uu QoS flow2 identified by QFI2, and the uplink data packets carried by PC5 QoS flow2 can be mapped to Uu QoS flow2.

[0130] Optionally, the second association can be a QoS rule, such as the UL Uu QoS rule, used to determine how to map uplink packets carried by the PC5 QoS flow to the Uu QoS flow. The UL Uu QoS rule may include a QFI, a PFI associated with the QFI, a packet filter set, and priorities. The QFI identifies the Uu QoS flow. Using a packet filter set allows packets meeting certain matching characteristics to be placed in the same QoS flow, effectively classifying the packets. A packet filter set may include multiple packet filters, each containing multiple fields for matching packets. These fields can be combined; if a field is missing, all packets are matched by default. Priority refers to the priority of the QoS flow identified by the QFI; for example, higher-priority QoS flows are transmitted first. For example, for two Uu QoS flows, the UL Uu QoS rule can be represented as {(QFI 1, PFI 1->QFI 1, packet filter set1, priority 1), (QFI 2, PFI 2->QFI 2, packet filter set2, priority 2)}, or as {(QFI 1, PFI 1, packet filter set1, priority 1), (QFI 2, PFI2, packet filter set2, priority 2)}. As another example, for three Uu QoS flows, the UL Uu QoS rule can be represented as {(QFI 1, PFI 1->QFI 1, packet filter set1, priority 1), (QFI 2, PFI 2->QFI 2, packet filter set2, priority 2), (QFI 3, PFI 3->QFI 3, packet filter set3, priority 1)}.

[0131] In this application, a third association between multiple PC5 QoS flows and multiple Uu QoS flows is used to relay UEs for downlink transmission. Specifically, the relay UE maps downlink data packets received from the UPF via the Uu QoS flow to the PC5 QoS flow, so that the PC5 QoS flow can send the downlink data packets to the remote UE. The third association can be represented by the association between the identifiers of the PC5 QoS flow and the Uu QoS flow, that is, by the association between the PFI and QFI. For example, the third association between two PC5 QoS flows and two Uu QoS flows can be represented as {(QFI1->PFI1),(QFI2->PFI2)}. (QFI1->PFI1) indicates that Uu QoS flow1 identified by QFI1 is associated with PC5 QoS flow1 identified by PFI1, and downlink data packets carried by Uu QoS flow1 can be mapped to PC5 QoS flow1. (QFI2->PFI2) indicates that Uu QoS flow2 identified by QFI2 is associated with Uu QoS flow2 identified by PFI2, and uplink data packets carried by Uu QoS flow2 can be mapped to PC5 QoS flow2.

[0132] Optionally, the third association can be a QoS rule, such as a DL PC5 QoS rule, used to determine how to map downlink packets carried by a Uu QoS flow to a PC5 QoS flow. A DL PC5 QoS rule may include a PFI, a QFI associated with the PFI, a packet filter set, and a priority. For example, for two PC5 QoS flows, a DL PC5 QoS rule can be represented as {(PFI 1, QFI 1->PFI 1, packet filter set1, priority 1), (PFI 2, QFI 2->PFI 2, packet filter set2, priority 2)}.

[0133] For example, taking two Uu QoS flows and two PC5 QoS flows as examples, the QoS rules involved can be seen in Table 1 below.

[0134] Table 1

[0135]

[0136] In Table 1, the DL Uu QoS rule is used by the relay UE to relay downlink data packets from the UPF, enabling hierarchical transmission over the Uu interface. The UL PC5 QoS rule can be generated by the relay UE or the remote UE, and is used to indicate the association between multiple PC5 QoS flows. For example, PC5 QoS flow 1 identified by PFI 1 is associated with PC5 QoS flow 2 identified by PFI 2. Furthermore, for three PC5 QoS flows, the UL PC5 QoS rule can indicate that PC5 QoS flow 1 is associated with PC5 QoS flow 2, PC5 QoS flow 2 is associated with PC5 QoS flow 3, and PC5 QoS flow 1 is associated with PC5 QoS flow 3.

[0137] It should be noted that the names of several QoS rules in Table 1 are for illustrative purposes only and do not constitute a limitation on this application.

[0138] A relay UE can simultaneously determine both a second and a third association to perform uplink and downlink transmissions. Alternatively, it can determine the second association when an uplink transmission is about to occur, and determine the third association when a downlink transmission is about to occur.

[0139] The aforementioned relay UE determines a DL Uu QoS rule for uplink transmission and a Uu PC5 QoS rule for downlink transmission, enabling the PC5 QoS flow and Uu QoS flow to be associated through different QoS rules for uplink and downlink transmissions. In another possible implementation, the relay UE determines a QoS rule applicable to both uplink and downlink transmissions. For example, this QoS rule can be represented as {(PFI 1, QFI 1), (PFI 2, QFI 2)}, where (PFI 1, QFI 1) indicates that the PC5 QoS flow1 identified by PFI 1 is associated with the Uu QoS flow1 identified by QFI 1. For downlink, downlink data packets carried by Uu QoS flow1 can be mapped to PC5 QoS flow1; for uplink, uplink data packets carried by PC5 QoS flow1 can be mapped to Uu QoS flow1.

[0140] Steps 406 to 409 below are the uplink transmission process, and steps 410 to 412 are the downlink transmission process.

[0141] 406. The remote UE maps the first uplink data packet to the PC5 QoS flow identified by the first flow identifier (i.e., PFI).

[0142] Optionally, before mapping uplink data packets to the PC5 QoS flow, the remote UE can perform hierarchical processing of the data flow according to its importance level, such as dividing it into important data packets (e.g., I-frames) and unimportant data packets (e.g., P-frames).

[0143] In one possible implementation, the remote UE determines that the first uplink data packet corresponds to the first PFI based on the attribute information of the first uplink data packet, combined with the first association relationship and the association relationship between multiple PC5 QoS flows, i.e., combining the LQoS rule and the UL PC5 QoS rule, thereby mapping the first uplink data packet to the PC5 QoS flow identified by the first PFI. The first uplink data packet can be any data packet to be sent. Attribute information can include one or more of the following: application-specific identifier, triples, and quintuples. The application-specific identifier refers to the application identifier corresponding to media services such as XR, used to identify which application the uplink data packet is for. Triples are used to identify the source IP address and destination IP address of the uplink data packet, and quintuples are used to identify the source IP address, destination IP address, source port, and destination port of the uplink data packet. Uplink data packets are identified using either triples or quintuples. The UL PC5 QoS rule can be generated by the remote UE, or generated by the relay UE and informed to the remote UE.

[0144] For example, the LQoS rule is represented as {(Importance Level 1, PFI 1), (Importance Level 2, PFI 2)}, and the UL PC5QoS rule is represented as {PFI 1, PFI 2, packet filter}. According to the UL PC5 QoS rule, it's impossible to determine whether to map uplink packets to the PC5 QoS flow identified by PFI 1 or the Uu QoS flow identified by PFI 2. According to the LQoS rule, uplink packets of importance level 1 can be mapped to the PC5 QoS flow identified by PFI 1, and uplink packets of importance level 2 can be mapped to the PC5 QoS flow identified by PFI 2, but it's unclear how to determine the importance level or the relationship between the two PC5 QoS flows. Combining the LQoS rule with the UL PC5 QoS rule allows matching the packet filter with the attribute information of the uplink packets, thereby determining the importance level of the uplink packets, mapping uplink packets of importance level 1 to the PC5 QoS flow identified by PFI 1, and mapping uplink packets of importance level 2 to the PC5 QoS flow identified by PFI 2. For example, the remote UE matches the packet filter with the attribute information of uplink data packet 1 and determines that the importance level of uplink data packet 1 is 1, corresponding to PFI 1. Then, uplink data packet 1 can be mapped to PC5 QoS flow1 identified by PFI 1. The remote UE matches the packet filter with the attribute information of uplink data packet 2 and determines that the importance level of uplink data packet 2 is 2, corresponding to PFI 2. Then, uplink data packet 2 can be mapped to PC5 QoS flow2 identified by PFI 2.

[0145] In another possible implementation, the remote UE can determine or generate a new rule to identify the first uplink data packet as corresponding to the first PFI, thereby mapping the first uplink data packet to the PC5 QoS flow identified by the first PFI. For example, this rule could be represented as {packet filter, (importance level 1, PFI 1), (importance level 2, PFI 2)}. The packet filter is matched with the attribute information of the uplink data packet to determine its importance level. Uplink data packets of importance level 1 are mapped to the PC5 QoS flow identified by PFI 1, and uplink data packets of importance level 2 are mapped to the PC5 QoS flow identified by PFI 2. The remote UE can generate a new rule based on the LQoS rule.

[0146] Optionally, when resources are limited between the remote UE and the relay UE, i.e., PC5 resources are limited, such as network congestion on the PC5 interface, if the priority of the PC5 QoS flow identified by the first PFI is lower than a threshold, the remote UE may discard uplink data packets mapped to the PC5 QoS flow identified by the first PFI. Here, "the priority of the PC5 QoS flow identified by the first PFI is lower than the threshold" can be understood as the QoS guarantee of the PC5 QoS flow identified by the first PFI being lower or lowest. The threshold can be the highest QoS guarantee level or a reference priority threshold specified by the protocol. Data packets mapped to PC5 QoS flows with lower QoS guarantees can be discarded, thereby reducing the impact on video quality.

[0147] 407. The remote UE sends a first uplink data packet to the relay UE through the PC5 QoS flow identified by the first PFI. Correspondingly, the relay UE receives the first uplink data packet from the remote UE through the PC5 QoS flow identified by the first PFI.

[0148] 408, The relay UE maps the first uplink data packet to the first Uu QoS flow according to the second association relationship.

[0149] Optionally, the relay UE maps the first uplink data packet to the first Uu QoS flow according to the packet filter and PFI in the UL Uu QoS rule. For example, the contents of the UL Uu QoS rule are shown in Table 1. If the first PFI is PFI1, the first uplink data packet can be mapped to the Uu QoS flow identified by QFI 1 according to the packet filter and PFI1; if the first PFI is PFI 2, the first uplink data packet can be mapped to the Uu QoS flow identified by QFI 2 according to the packet filter.

[0150] 409. The relay UE sends a first uplink data packet to the third network device through the first Uu QoS flow. Correspondingly, the third network device receives the first uplink data packet from the relay UE through the first Uu QoS flow. The third network device can be a UPF in a 5G system, or a network element with the same function as a UPF in future communications; this application uses a UPF as an example.

[0151] The relay UE sends the first uplink data packet to the UPF, which can be transparently transmitted through the access network equipment. Upon receiving the first uplink data packet, the UPF can forward it to the XR server.

[0152] For example, the uplink transmission shown in steps 406 to 409 can be found in [reference needed]. Figure 5 The example diagram is shown. Figure 5 In this scenario, it is assumed that the QoS guarantee of PC5 QoS flow1 is higher than that of PC5 QoS flow2, the QoS guarantee of Uu QoS flow1 is higher than that of Uu QoS flow2, and the importance of uplink data packet 1 is higher than that of uplink data packet 2. For example, uplink data packet 1 is an I-frame, and uplink data packet 2 is a P-frame. Based on the attribute information of the uplink data packets, and combined with the first association relationship and the association relationships between multiple PC5 QoS flows, the remote UE determines that uplink data packet 1 corresponds to PFI 1 and uplink data packet 2 corresponds to PFI 2. Uplink data packet 1 is mapped to PC5 QoS flow1 identified by PFI 1, and is sent to the relay UE through PC5 QoS flow1; uplink data packet 2 is mapped to PC5 QoS flow2 identified by PFI 2, and is sent to the relay UE through PC5 QoS flow2. When the relay UE receives uplink data packet 1 and uplink data packet 2, it maps uplink data packet 1 to Uu QoS flow1 identified by QFI 1 according to the second association relationship, and sends uplink data packet 1 to the UPF through Uu QoS flow1; it maps uplink data packet 2 to Uu QoS flow2 identified by QFI 2, and sends uplink data packet 2 to the UPF through Uu QoS flow2. If the QoS guarantee of Uu QoS flow2 is higher than that of Uu QoS flow1, then the relay UE maps uplink data packet 1 to Uu QoS flow2 identified by QFI 1 and uplink data packet 2 to Uu QoS flow1 identified by QFI 1 according to the second association relationship.

[0153] Optionally, if PC5 resources are limited between the remote UE and the relay UE, the remote UE may discard uplink packets mapped to PC5 QoS flow2.

[0154] 410. The UPF sends the first downlink data packet to the relay UE through the Uu QoS flow identified by the second flow identifier (QFI). Correspondingly, the relay UE receives the first downlink data packet from the UPF through the Uu QoS flow identified by the second QFI.

[0155] When the UPF receives a data stream from the XR server, it sends the data stream to the relay UE through multiple Uu QoS flows based on the importance level of the data stream. For example, there may be two Uu QoS flows: one Uu QoS flow carries important data packets, and the other Uu QoS flow carries less important data packets.

[0156] 411, The relay UE maps the first downlink data packet to the second PC5 QoS flow according to the third association relationship.

[0157] Optionally, the relay UE maps the first downlink data packet to the second PC5 QoS flow according to the packet filter and QFI in the DL PC5 QoS rule. For example, the contents of the DL PC5 QoS rule are shown in Table 1. If the second QFI is QFI 1, the first downlink data packet can be mapped to the PC5 QoS flow identified by PFI 1 according to the packet filter and QFI 1; if the first QFI is QFI 2, the first downlink data packet can be mapped to the PC5 QoS flow identified by PFI 2 according to the packet filter.

[0158] Optionally, when resources are limited between the remote UE and the relay UE, if the priority of the Uu QoS flow identified by the second QFI is lower than a threshold, the relay UE may discard downlink data packets mapped to the Uu QoS flow identified by the second QFI. Here, "the priority of the Uu QoS flow identified by the second QFI is lower than the threshold" can be understood as the QoS guarantee of the Uu QoS flow identified by the second QFI being lower or the lowest. The threshold can be the highest QoS guarantee level or a reference priority threshold specified by the protocol. Data packets mapped to PC5 QoS flows with lower QoS guarantees can be discarded, thereby reducing the impact on video quality.

[0159] 412, the relay UE sends the first downlink data packet to the remote UE through the second PC5 QoS flow. Correspondingly, the remote UE receives the first downlink data packet from the relay UE through the second PC5 QoS flow.

[0160] For example, the uplink transmission shown in steps 410 to 412 can be found in [reference needed]. Figure 6 The example diagram is shown. Figure 6In this scenario, it is assumed that the QoS guarantee of PC5 QoS flow1 is higher than that of PC5 QoS flow2, the QoS guarantee of Uu QoS flow1 is higher than that of Uu QoS flow2, and the importance of uplink data packet 1 is higher than that of uplink data packet 2. For example, uplink data packet 1 is an I-frame, and uplink data packet 2 is a P-frame. Based on the attribute information of the uplink data packets, and combined with the first association relationship and the association relationships between multiple PC5 QoS flows, the remote UE determines that uplink data packet 1 corresponds to PFI 1 and uplink data packet 2 corresponds to PFI 2. Uplink data packet 1 is mapped to PC5 QoS flow1 identified by PFI 1, and is sent to the relay UE through PC5 QoS flow1; uplink data packet 2 is mapped to PC5 QoS flow2 identified by PFI 2, and is sent to the relay UE through PC5 QoS flow2. When the relay UE receives uplink data packet 1 and uplink data packet 2, it maps uplink data packet 1 to Uu QoS flow1 identified by QFI 1 according to the second association relationship, and sends uplink data packet 1 to the UPF through Uu QoS flow1; it maps uplink data packet 2 to Uu QoS flow2 identified by QFI 2, and sends uplink data packet 2 to the UPF through Uu QoS flow2. If the QoS guarantee of Uu QoS flow2 is higher than that of Uu QoS flow1, then the relay UE maps uplink data packet 1 to Uu QoS flow2 identified by QFI 1 and uplink data packet 2 to Uu QoS flow1 identified by QFI 1 according to the second association relationship.

[0161] Optionally, if PC5 resources are limited between the remote UE and the relay UE, the relay UE may discard uplink packets mapped to PC5 QoS flow2.

[0162] exist Figure 4 In this process, the relay UE establishes a LQoS-enabled PDU session based on the first message sent by the remote UE to relay data between the XR server and the remote UE, thereby reducing the impact on the video quality on the remote UE. Based on the established LQoS-enabled PDU session, the relay UE establishes multiple PC5 QoS flows and multiple Uu QoS flows with related relationships, and associates the multiple PC5 QoS flows with the multiple Uu QoS flows to achieve layered transmission in the relay scenario. When PC5 resources are limited, the remote UE can discard uplink data packets mapped to PC5 QoS flows with low QoS guarantees, and the relay UE can discard downlink data packets mapped to PC5 QoS flows with low QoS guarantees, ensuring the transmission of important data and thus reducing the impact on video quality.

[0163] Please see Figure 7 This is a flowchart illustrating the data transmission method provided in Embodiment 1 of this application. The method may include, but is not limited to, the following steps:

[0164] 700, PCF configures RSC and the corresponding PDU session parameters for the relay UE and remote UE.

[0165] The PDU session parameters include first information. In one implementation, the first information can be a parameter, such as QoS control type. The value of this parameter can instruct the relay UE to establish a PDU session supporting LQoS, or instruct the relay UE to establish a PDU session supporting independent QoS. In another implementation, the first information can be LQoS, directly instructing the relay UE to establish a PDU session supporting LQoS. For example, the correspondence between RSC and PDU session parameters can be represented as RSC->PDU session parameters(PDU session type, DNN, SSC mode, S-NSSAI, access type preference, LQoS), where the PDU session parameters carry LQoS, and by default instruct the relay UE to establish a PDU session supporting LQoS.

[0166] The PCF sends its configured RSC and the corresponding PDU session parameters to the remote UE and the relay UE, respectively.

[0167] 701. The remote UE and the relay UE perform a discovery procedure. The discovery procedure is performed based on the RSC corresponding to the PDU session parameters, which includes the first information.

[0168] For Mode A, if the relay UE supports LQoS, then the broadcast-associated PDU session parameters include the LQoS RSC.

[0169] For Mode B, the remote UE broadcasts an RSC, the corresponding PDU session parameter of which indicates LQoS. If the relay UE supports LQoS, it can respond to the remote UE. The remote UE can broadcast this RSC through the first message.

[0170] 702. The remote UE sends a connection request message to the relay UE. Correspondingly, the relay UE receives the connection request message from the remote UE. This connection request message can be an L2 link establishment request message or a direct communication request message, etc., used to request the establishment of a communication connection with the relay UE.

[0171] 703. The relay UE determines to establish a PDU session supporting LQoS based on the RSC during the discovery process. The PDU session parameters corresponding to the RSC include the first piece of information.

[0172] 704. The relay UE establishes a PDU session supporting LQoS. The implementation process of step 704 can be found in [link to documentation]. Figure 7-1 As shown, Figure 7-1 The process shown may include, but is not limited to, the following steps:

[0173] 7041, the relay UE sends a non-access stratum (NAS) message to the AMF. Correspondingly, the AMF receives the NAS message from the relay UE.

[0174] The NAS message is used to request the establishment of a PDU session. In one implementation, the NAS message includes a PDU session establishment request message and first information, used to request the establishment of a PDU session supporting LQoS. In another implementation, the NAS message includes a PDU session establishment request message, which includes first information, and is used to request the establishment of a PDU session supporting LQoS.

[0175] 7042, AMF selects SMF that supports LQoS.

[0176] 7043, the AMF sends a PDU session establishment context request message to the selected SMF. Correspondingly, the SMF receives the PDU session establishment context request message from the AMF.

[0177] In one implementation, the PDU session establishment context request message includes a PDU session establishment request message and first information, used to request the establishment of a PDU session supporting LQoS. In another implementation, the PDU session establishment context request message includes a PDU session establishment request message, which includes first information, and is used to request the establishment of a PDU session supporting LQoS.

[0178] It is understandable that a relay UE can send a PDU session establishment request message and first information to an SMF that supports LQoS via an AMF; or, a relay UE can send a PDU session establishment request message to an SMF that supports LQoS via an AMF, and the PDU session establishment request message includes the first information.

[0179] 7044, SMF obtains LQoS information from PCF. This LQoS information includes packet filters for media services such as XR, as well as QoS parameters used to implement layered quality of service.

[0180] 7045, SMF generates LQoS rule.

[0181] Optionally, SMF can generate LQoS rules based on LQoS information. The LQoS rules can be referenced from... Figure 4 The specific description of the LQoS rule in step 402 will not be repeated here.

[0182] 7046, the SMF sends a PDU session establishment context response message to the AMF. Correspondingly, the AMF receives the PDU session establishment context response message from the SMF.

[0183] The PDU session establishment context response message includes an LQoS rule and an LQoS reception indication, which indicates that an LQoS-supporting PDU session has been established.

[0184] 7047. The AMF sends a PDU session establishment accept message to the relay UE. Correspondingly, the relay UE receives the PDU session establishment accept message from the AMF. The AMF can send the PDU session establishment accept message to the relay UE through the access network equipment, or directly to the relay UE.

[0185] The PDU session establishment acceptance message includes LQoS rules.

[0186] 705, the relay UE sends a connection acceptance message to the remote UE. Correspondingly, the remote UE receives the connection acceptance message from the relay UE. The connection acceptance message is used in response to a connection request message, and can be an L2 link establishment response message or a direct communication response message, etc., indicating that the relay UE agrees to establish a communication connection.

[0187] The connection acceptance message includes an LQoS rule so that the remote UE can combine it with the association between multiple PC5 QoS flows to determine the PFI corresponding to the uplink data packet.

[0188] 706, IP address allocation.

[0189] 707. The relay UE sends a remote UE report to the SMF. Correspondingly, the SMF receives the remote UE report from the relay UE.

[0190] Steps 706 and 707 can be referenced. Figure 3 Steps 105 and 107 in the text.

[0191] 708. The remote UE establishes a connection with the XR server via a relay method.

[0192] 709. The remote UE sends a first connection message to the relay UE. Correspondingly, the relay UE receives the first connection message from the remote UE. The first connection message may be, for example, a connection modification request message to trigger the relay UE to establish multiple related PC5 QoS flows.

[0193] The first connection message is used to inform the relay UE that the PC5 QoS flows performing LQoS have a correlation, that is, to indicate the correlation between multiple PC5 QoS flows.

[0194] In one implementation, the PFI of the associated PC5 QoS flow is added to the PC5 QoS context in the first connection message. For example, the PC5 QoS context is defined as: `PC5 QoS context(PFI; correlated PFI; PC5 QoS parameters, PC5 QoS rule(PFI, PC5packet filter, precedence value))`. For instance, for two PC5 QoS flows, the PC5 QoS context may include PFI 1 and PFI 2, indicating that PC5 QoS flow 1 identified by PFI 1 is associated with PC5 QoS flow 2 identified by PFI 2.

[0195] In another implementation, the PFI of the associated PC5 QoS flow is added to the PC5 QoS rule in the PC5 QoS context. This PC5 QoS rule is the UL PC5 QoS rule in Table 1. For example, the PC5 QoS context is defined as: (PFI; PC5 QoS parameters, PC5 QoS rule (PFI, correlated PFI; PC5 packet filter, precedence value)). For instance, for two PC5 QoS flows, the PC5 QoS rule in the PC5 QoS context may include PFI 1 and PFI 2, indicating that PC5 QoS flow 1 identified by PFI 1 is associated with PC5 QoS flow 2 identified by PFI 2.

[0196] 710, The relay UE establishes multiple PC5 QoS flows with a relationship, and establishes multiple UuQoS flows with a relationship.

[0197] The relay UE establishes multiple PC5 QoS flows with a relationship based on the first connection message. Establishing multiple Uu QoS flows with a relationship is completed by initiating a PDU session modification procedure. The relay UE maps Uu QoS parameters using PC5 QoS parameters requested by the remote UE. The PC5 QoS parameters may include one or more of the following: PC5 5G QoS identifier (PQI), guaranteed flow bit rate (GFBR), maximum flow bit rate (MFBR), and PC5 link-aggregate maximum bit rate (PC5 LINK-AMBR). Uu QoS parameters may include one or more of the following: 5G QoS identifier (5QI), GFBR, MFBR, and average window. For example, 5QI can be mapped using PQI.

[0198] For PDU session modification procedures, please refer to [link / reference]. Figure 7-2 As shown, Figure 7-2 The process shown may include, but is not limited to, the following steps:

[0199] 7101, the relay UE sends a PDU session modification request message to the AMF. Correspondingly, the AMF receives the PDU session modification request message from the relay UE. This PDU session modification request message is used to request operations such as adding, modifying, or deleting Uu QoS flows, as well as the corresponding QoS parameters.

[0200] 7102, the AMF sends a PDU session update context to the SMF. Correspondingly, the SMF receives the PDU session update context from the AMF, where the PDU session update context message includes a PDU session modification request message sent by the UE.

[0201] 7103, the SMF sends an N4 session modification request message to the UPF. Correspondingly, the UPF receives the N4 session modification request message from the SMF.

[0202] The N4 session modification request message includes a QoS rule, which indicates the association between multiple Uu QoS flows. For example, the QoS rule may include (QFI 1, QFI 2), indicating that Uu QoS flow 1 identified by QFI 1 is associated with Uu QoS flow 2 identified by QFI 2.

[0203] 7104, the SMF sends a PDU session update context response to the AMF. Correspondingly, the AMF receives the PDU session update context response from the SMF.

[0204] The PDU session update context response includes a PDU session modification command, which includes the QoS rule from step 7103 and the Uu QoS parameters corresponding to QFI. For example, the PDU session modification command includes QoS rule(QFI1, QFI2), the Uu QoS parameters corresponding to QFI1, and the Uu QoS parameters corresponding to QFI2.

[0205] 7105, the AMF sends a PDU session modification response message to the relay UE. Correspondingly, the relay UE receives the PDU session modification response message from the AMF. The AMF can send the PDU session modification response message to the relay UE through the access network equipment, or directly to the relay UE.

[0206] The PDU session modification response message includes the aforementioned PDU session modification command, so that the relay UE can learn about the relationship between multiple UuQoS flows.

[0207] Figure 7-2 The process shown can be understood as the remote UE triggering the relay UE to establish a Uu QoSflow with a correlation.

[0208] 711, the relay UE generates DL PC5 QoS rule and UL Uu QoS rule. Step 711 can be found in [reference needed]. Figure 4 Step 405 in the previous section will not be repeated here.

[0209] 712, the relay UE sends a third connection message to the remote UE. Correspondingly, the remote UE receives the third connection message from the relay UE. The third connection message is used in response to the first connection message, and may be, for example, a connection modification acceptance message.

[0210] 713, Uplink transmission process, please refer to Figure 4 Steps 406 to 409 in the process.

[0211] 714, Downlink transmission process, please refer to Figure 4 Steps 410 to 412 in the process.

[0212] exist Figure 7In the first embodiment shown, the relay UE and the remote UE perform a discovery process based on the RSC corresponding to the PDU session parameters including the first information. The relay UE establishes a PDU session supporting LQoS based on the first information to relay data between the XR server and the remote UE, thereby reducing the impact on the video effect on the remote UE side.

[0213] Please see Figure 8 This is a flowchart illustrating the data transmission method provided in Embodiment 2 of this application. The method may include, but is not limited to, the following steps:

[0214] 801. The remote UE and the relay UE perform the discovery process. Step 801 can be found in [reference needed]. Figure 3 Step 103 in the previous section will not be repeated here.

[0215] 802. The remote UE sends a connection request message to the relay UE. Correspondingly, the relay UE receives the connection request message from the remote UE. This connection request message is used to request the establishment of a communication connection with the relay UE, and can be an L2 link establishment request message or a direct communication request message, etc.

[0216] The connection request message includes first information, which can be an indication, such as LQoS indication information, used to instruct the relay UE to establish a PDU session supporting LQoS. For example, when the remote UE determines that the relay service is a media service such as XR, it sends a connection request message carrying LQoS indication information to the relay UE.

[0217] 803, The relay UE determines to establish a PDU session supporting LQoS based on the first information.

[0218] 804, Relay UE establishes a PDU session supporting LQoS.

[0219] 805, the relay UE sends a connection accept message to the remote UE. Correspondingly, the remote UE receives the connection accept message from the relay UE.

[0220] 806, IP address allocation.

[0221] 807. The relay UE sends a remote UE report to the SMF. Correspondingly, the SMF receives the remote UE report from the relay UE.

[0222] 808, the remote UE establishes a connection with the XR server via relay.

[0223] 809. The remote UE sends a first connection message to the relay UE. Correspondingly, the relay UE receives the first connection message from the remote UE. The first connection message indicates that multiple PC5 QoS flows are related.

[0224] 810, The relay UE establishes multiple PC5 QoS flows with a relationship, and establishes multiple UuQoS flows with a relationship.

[0225] Steps 804 to 810 can be referenced. Figure 7 The descriptions of steps 704 to 710 in the previous section will not be repeated here.

[0226] Step 811: Generate DL PC5 QoS rule and UL Uu QoS rule for the relay UE. Step 811 can be found in [reference needed]. Figure 4 Step 405 in the previous section will not be repeated here.

[0227] 812, the relay UE sends a third connection message to the remote UE. Correspondingly, the remote UE receives the third connection message from the relay UE.

[0228] 813, Uplink transmission process, please refer to Figure 4 Steps 406 to 409 in the process.

[0229] 814, Downlink transmission process, please refer to Figure 4 Steps 410 to 412 in the process.

[0230] exist Figure 8 In the second embodiment shown, the remote UE sends LQoS indication information to the relay UE, instructing the relay UE to establish a PDU session that supports LQoS in order to relay data between the XR server and the remote UE, thereby reducing the impact on the video quality on the remote UE side.

[0231] Please see Figure 9 This is a flowchart illustrating the data transmission method provided in Embodiment 3 of this application. The method may include, but is not limited to, the following steps:

[0232] Steps 901 to 908 can be referenced. Figure 7 Steps 701 to 708 in the above, or refer to... Figure 8 Steps 801 to 808 in the process.

[0233] 909, XR server and SMF execution policy modification process.

[0234] The process may include: the XR server sending a request message to the PCF, the request message including the requested QoS; the PCF receiving the request message, generating the corresponding policy and charging control (PCC) policy based on the requested QoS, and sending the PCC policy to the SMF.

[0235] 910. Based on the association between the relay UE and the remote UE, the SMF determines and triggers the relay UE to establish multiple Uu QoS flows with association.

[0236] The association between the relay UE and the remote UE can be obtained based on the remote UE report in step 707 or step 807. The SMF can trigger the relay UE to establish multiple Uu QoS flows with an association by initiating a PDU session modification procedure. The PDU session modification procedure may include steps 911 to 913 below.

[0237] 911. The SMF and UPF execute the N4 session modification procedure. This procedure may include the SMF sending an N4 session modification request message to the UPF, and the UPF sending an N4 session modification acceptance message to the SMF.

[0238] 912, SMF sends N1N2 message to AMF. Correspondingly, AMF receives N1N2 message from SMF.

[0239] The N1N2 message, for example, could be Namf_Communication_N1N2MessageTransfer. This message includes a PDU session modification message, such as a PDU session modification command. The PDU session modification message may include a QoS rule, which indicates the association between multiple Uu QoS flows. For example, for two Uu QoS flows, the QoS rule includes QFI1 and QFI2, indicating that Uu QoS flow1 identified by QFI1 is associated with Uu QoS flow2 identified by QFI2. The QoS rule also includes identification information of the remote UE, such as the remote UE's user identifier and / or IP address, used to indicate the establishment of multiple associated Uu QoS flows for the remote UE.

[0240] 913, the AMF sends a PDU session modification message to the relay UE. Correspondingly, the relay UE receives the PDU session modification message from the AMF.

[0241] When the AMF sends a PDU session modification message to the relay UE, it can send it directly via a NAS message or through the access network device. For example, the AMF sends an N2 message to the access network device, which includes the PDU session modification message, and the access network device sends an AN message to the relay UE, which also includes the PDU session modification message. The content of the PDU session modification message can be found in the description in step 912.

[0242] 914, The relay UE establishes multiple Uu QoS flows with a relationship, and establishes multiple PC5 QoS flows with a relationship.

[0243] Based on the aforementioned PDU session modification message, the relay UE establishes multiple Uu QoS flows with correlation for the remote UE. Based on the established multiple Uu QoS flows with correlation, multiple PC5 QoS flows with correlation are established, and a UL PC5 QoS rule is generated.

[0244] Step 915: Generate or update DL PC5 QoS rules and UL Uu QoS rules for relay UEs. See step 915 for details. Figure 4 Step 405 in the previous section will not be repeated here.

[0245] Optionally, if the relay UE has generated DL PC5 QoS rule and UL Uu QoS rule, the relay UE can update the generated DL PC5 QoS rule and / or UL Uu QoS rule, so that the relay UE can dynamically adjust the association between PC5 QoS flow and Uu QoS flow to flexibly utilize network resources.

[0246] 916, the relay UE sends a second connection message to the remote UE. Correspondingly, the remote UE receives a first connection message from the relay UE. The second connection message indicates that multiple PC5 QoS flows are associated. For example, the second connection message could be a connection modification request message to trigger the remote UE and the relay UE to establish multiple associated PC5 QoS flows.

[0247] The second connection message is used to inform the remote UE that multiple PC5 QoS flows are related.

[0248] In one implementation, the PFI of the associated PC5 QoS flow is added to the PC5 QoS context in the second connection message. For example, the PC5 QoS context is defined as: PC5 QoS context(PFI; correlated PFI; PC5 QoS parameters, PC5 QoS rule(PFI, PC5packet filter, precedence value)). For instance, for two PC5 QoS flows, the PC5 QoS context may include PFI 1 and PFI 2, indicating that PC5 QoS flow 1 identified by PFI 1 is associated with PC5 QoS flow 2 identified by PFI 2.

[0249] In another implementation, the PFI of the associated PC5 QoS flow is added to the PC5 QoS rule in the PC5 QoS context. This PC5 QoS rule is the UL PC5 QoS rule in Table 1. For example, the PC5 QoS context is defined as: (PFI; PC5 QoS parameters, PC5 QoS rule (PFI, correlated PFI; PC5 packet filter, precedence value)). For instance, for two PC5 QoS flows, the PC5 QoS rule in the PC5 QoS context may include PFI 1 and PFI 2, indicating that PC5 QoS flow 1 identified by PFI 1 is associated with PC5 QoS flow 2 identified by PFI 2.

[0250] 917, the remote UE sends a fourth connection message to the relay UE. Correspondingly, the relay UE receives the fourth connection message from the remote UE. This fourth connection message is used in response to the second connection message; for example, it could be a connection modification acceptance message.

[0251] 918, the uplink transmission process, can be referenced. Figure 4 Steps 406 to 409 in the process.

[0252] 919, Downlink transmission process, please refer to Figure 4 Steps 410 to 412 in the process.

[0253] exist Figure 9 In the illustrated embodiment three, the network triggers the relay UE to establish multiple Uu QoS flows with a relationship. The relay UE requests to establish multiple PC5 QoS flows with a relationship with the remote UE, allowing the relay UE to dynamically adjust the relationship between the PC5 QoS flows and the Uu QoS flows, thereby flexibly utilizing network resources. Figure 7 or Figure 8 In the illustrated embodiment, the remote UE requests the relay UE to establish multiple PC5 QoS flows with an association relationship, and then the relay UE establishes multiple Uu QoS flows with an association relationship.

[0254] This application also provides the following embodiments:

[0255] Example 1. A data transmission method, the method comprising:

[0256] The relay device receives a first message from a remote device. The first message is used to discover the remote device or request to establish a communication connection with the relay device. The first message includes a relay service code, and the protocol data unit session parameters corresponding to the relay service code include first information. Alternatively, the first message includes first information. The first information is used to establish a protocol data unit session that supports hierarchical quality of service. The protocol data unit session is used to relay data from the remote device. Data from the remote device is transmitted through the protocol data unit session.

[0257] Example 2. The method according to Example 1 further includes: the relay device receiving configuration information from the first network device, the configuration information including a relay service code and protocol data unit session parameters corresponding to the relay service code, wherein the protocol data unit session parameters include first information.

[0258] Example 3. The method according to Example 1 or 2 further includes: the relay device sending a second message to the remote device, the second message being used to determine a first association between the uplink data packet and the first type of quality of service flow, the first type of quality of service flow being used for data transmission between the relay device and the remote device.

[0259] Example 4. The method according to Example 1 or 2 further includes: the relay device sending a request message to the second network device for establishing a protocol data unit session, the request message including first information.

[0260] Example 5. The method according to any one of Examples 1 to 4 further includes: the relay device establishing a plurality of first-type quality of service flows with an association relationship, the first-type quality of service flows being used for data transmission between the relay device and a remote device; establishing a plurality of second-type quality of service flows with an association relationship, the plurality of second-type quality of service flows being associated with a protocol data unit session and being used for data transmission between the relay device and a third network device; and determining a second association relationship between the plurality of first-type quality of service flows and the plurality of second-type quality of service flows.

[0261] Example 6. The method according to Example 5 further includes: a relay device receiving a first uplink data packet from a remote device through a quality of service flow identified by a first flow identifier; mapping the first uplink data packet to a first quality of service flow among multiple second-type quality of service flows according to a second association relationship; wherein, the first flow identifier is used to identify the quality of service flow carrying the first uplink data packet among multiple first-type quality of service flows; the second association relationship includes the association relationship between the first quality of service flow and the quality of service flow identified by the first flow identifier; and sending the first uplink data packet to a third network device through the first quality of service flow.

[0262] Example 7. The method according to Example 5 further includes: the relay device determining a third association relationship between a plurality of first-type quality of service flows and a plurality of second-type quality of service flows.

[0263] Example 8. The method according to Example 7 further includes: a relay device receiving a first downlink data packet from a third network device through a quality of service flow identified by a second flow identifier; mapping the first downlink data packet to a second quality of service flow among multiple first-class quality of service flows according to a third association relationship; wherein, the second flow identifier is used to identify the quality of service flow carrying the first downlink data packet among multiple second-class quality of service flows; the third association relationship includes the association relationship between the second quality of service flow and the quality of service flow identified by the second flow identifier; and sending the first downlink data packet to a remote device through the second quality of service flow.

[0264] Example 9. The method according to Example 8 further includes: when resources are limited between the remote device and the relay device, if the priority of the second quality of service flow is lower than a threshold, the relay device discards the second downlink data packet mapped to the second quality of service flow.

[0265] Example 10. The method according to Example 5 further includes: the relay device receiving a first connection message from a remote device, the first connection message being used to request the establishment of multiple first-type quality of service flows with an association relationship, the first connection message indicating the association relationship between the multiple first-type quality of service flows.

[0266] Example 11. The method according to Example 5 further includes: the relay device receiving a Protocol Data Unit Session Modification message from the second network device, the Protocol Data Unit Session Modification message including the identification information of the remote device;

[0267] The relay equipment establishes multiple related Type I quality of service flows, including:

[0268] The relay device establishes multiple related Type I quality of service flows with the remote device based on the protocol data unit session modification message.

[0269] Example 12. The method according to Example 11 further includes: the relay device updating the second association relationship and / or the third association relationship.

[0270] Example 13. The method according to Example 11 further includes: the relay device sending a second connection message to the remote device, the second connection message indicating the association relationship between multiple first-type quality of service flows.

[0271] For details regarding the operation of the relay equipment in Examples 1 to 13, please refer to... Figure 4 , Figures 7 to 9 The relevant descriptions of relay equipment are omitted here.

[0272] Example 14. A data transmission method, the method comprising:

[0273] The remote device sends a first message to the relay device. The first message is used to discover the remote device or request to establish a communication connection with the relay device. The first message includes a relay service code, and the protocol data unit session parameters corresponding to the relay service code include first information. Alternatively, the first message includes first information. The first information is used to establish a protocol data unit session that supports hierarchical quality of service. The protocol data unit session is used to relay data from the remote device.

[0274] Example 15. The method according to Example 14 further includes: the remote device receiving configuration information from the first network device, the configuration information including a relay service code and protocol data unit session parameters corresponding to the relay service code, wherein the protocol data unit session parameters include first information.

[0275] Example 16. The method according to Example 14 or 15 further includes: the remote device receiving a second message from the relay device, the second message being used to determine a first association between an uplink data packet and a first type of quality of service flow, the first type of quality of service flow being used for data transmission between the relay device and the remote device.

[0276] Example 17. The method according to Example 16 further includes: the remote device determining that the first uplink data packet corresponds to a first flow identifier based on the attribute information of the first uplink data packet and in combination with the first association relationship and the association relationship between multiple first-type quality of service flows; the attribute information includes one or more of a specific application identifier, a triple, and a quintuple; the first-type quality of service flow is used for data transmission between the relay device and the remote device; the first uplink data packet is mapped to one of the multiple first-type quality of service flows identified by the first flow identifier; and the first uplink data packet is sent to the relay device through the quality of service flow identified by the first flow identifier.

[0277] Example 18. The method according to Example 17 further includes: the remote device sending a first connection message to the relay device, the first connection message being used to request the establishment of multiple first-type quality of service flows with an association relationship, the first connection message indicating the association relationship between the multiple first-type quality of service flows.

[0278] Example 19. The method according to Example 17 further includes: the remote device receiving a second connection message from the relay device, the second connection message indicating the association between multiple first-type quality of service flows.

[0279] Example 20. The method according to Example 17 further includes: when resources are limited between the remote device and the relay device, if the priority of the quality of service flow identified by the first flow identifier is lower than a threshold, discarding the second uplink data packet mapped to the quality of service flow identified by the first flow identifier.

[0280] For details regarding the operation of the remote device in Examples 14 to 20, please refer to... Figure 4 , Figures 7 to 9 The relevant descriptions of remote devices are not repeated here.

[0281] To implement the data transmission method provided in this application embodiment, the relay device and the remote device may each include a hardware structure and a software module, respectively, to implement the above functions in the form of a hardware structure, a software module, or a hardware structure plus a software module. One of the above functions may be executed in the form of a hardware structure, a software module, or a hardware structure plus a software module.

[0282] Figure 10 This illustrates a form of communication between a relay device and a remote device, such as... Figure 10 As shown, relay device 10 includes a processor 101, a memory 102, and a transceiver 103. Transceiver 103 includes a transmitter 1031, a receiver 1032, and an antenna 1033. Remote device 20 also includes a processor 201, a memory 202, and a transceiver 203. Transceiver 203 includes a transmitter 2031, a receiver 2032, and an antenna 2033. Receiver 1032 can be used to receive messages through antenna 1033, and transmitter 1031 can be used to send messages to remote device 20 through antenna 1033. Transmitter 2031 can be used to send messages to relay device 10 through antenna 2033, and receiver 2032 can be used to receive messages sent by relay device 10 through antenna 2033.

[0283] Figure 11 and Figure 12 The diagram illustrates the possible communication devices provided in the embodiments of this application. These communication devices can be used to implement the functions of relay devices or remote devices in the above method embodiments, and thus can also achieve the beneficial effects of the above method embodiments.

[0284] Figure 11 The communication device 1100 shown may include a communication unit 1101 and a processing unit 1102. The communication unit 1101 may include a transmitting unit and / or a receiving unit. The transmitting unit is used to implement the transmitting function, and the receiving unit is used to implement the receiving function. The communication unit 1101 can implement both the transmitting and / or receiving functions. The communication unit may also be described as a transceiver unit.

[0285] The communication device 1100 can be a relay device, a device within a relay device, or a device that has the function of a relay device.

[0286] In one embodiment, the communication device 1100 can perform the above-described... Figure 4 , Figures 6 to 9 The operation of the relay device in the illustrated embodiment. For example, in Figure 4 In the illustrated embodiment, communication unit 1101 is used to receive a first message from a remote device; processing unit 1102 is used to establish a Protocol Data Unit (PDU) session supporting hierarchical Quality of Service (HFS) based on the first message. A more detailed description of the processing unit 1102 and communication unit 1101 can be found in [reference needed]. Figure 4 , Figures 7 to 9 The relevant descriptions in the illustrated embodiments are obtained.

[0287] The communication device 1100 can be a remote device, a device within a remote device, or a device with remote device functionality.

[0288] In one embodiment, the communication device 1100 can perform the above-described... Figure 4 , Figures 7 to 9 The illustrated embodiment describes the relevant operations of the remote device. For example, in... Figure 4 In the illustrated embodiment, the communication unit 1101 is used to send a first message to the relay device. A more detailed description of the processing unit 1102 and the communication unit 1101 can be found in [reference needed]. Figure 4 , Figures 7 to 9 The relevant descriptions in the illustrated embodiments are as follows.

[0289] Figure 12 The communication device 1200 shown may include a processor 1201 and an interface circuit 1202. The processor 1201 and the interface circuit 1202 are coupled to each other. It is understood that the interface circuit 1202 may be an interface circuit or an input / output interface. Optionally, the communication device 1200 may also include a memory 1203 for storing instructions executed by the processor 1201, or storing input data required by the processor 1201 to execute instructions, or storing data generated after the processor 1201 executes instructions.

[0290] For example, the communication device 1200 can be a relay device: the interface circuit 1202 is used to perform... Figure 4 Numbers 401, 403, 407, 409, 410, and 412 in the series... Figure 7 The numbers 702, 705, 707, 709, and 712 in the text are: Figure 8 The numbers 802, 805, 807, 809, and 812 in the text are likely part of a larger document. Figure 9 913, 916, and 917; processor 1201 executes Figure 4 Numbers 402, 404, 405, 408, and 411 in the series... Figure 7 The numbers 703, 706, 710, and 711 in the text are likely part of a larger document and should be left as is. Figure 8 The numbers 803, 806, 810, and 811 in the text are likely part of a larger document and should be left as is. Figure 9 914 and 915 in the middle.

[0291] For example, the communication device 1200 can be a remote device: the interface circuit 1202 is used to perform... Figure 4 Numbers 401, 403, 407, 409, 410, and 412 in the series... Figure 7 The numbers 702, 705, 707, 709, and 712 in the text are: Figure 8 The numbers 802, 805, 807, 809, and 812 in the text are likely part of a larger document. Figure 9 913, 916, and 917; processor 1201 executes Figure 4 406 in the middle.

[0292] When the aforementioned communication device is a chip used in a relay device, the chip in the relay device implements the functions of the relay device in the above method embodiments. The chip receives information from other modules (such as radio frequency modules or antennas) in the relay device, which is sent to the relay device by a remote device, access network device, or core network element; or, the chip sends information to other modules (such as radio frequency modules or antennas) in the relay device, which is sent to a remote device, access network device, or core network element by the relay device.

[0293] When the aforementioned communication device is a chip applied to a remote device, the chip of the remote device implements the functions of the remote device in the above method embodiments. The chip receives information from other modules (such as radio frequency modules or antennas) in the remote device, which is information sent to the remote device by a relay device; or, the chip sends information to other modules (such as radio frequency modules or antennas) in the remote terminal device, which is information sent to the relay device by the remote terminal device.

[0294] It is understood that the processor in the embodiments of this application can be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. The general-purpose processor can be a microprocessor or any conventional processor. When the device (relay device or remote device) sends information, it outputs information through the chip's interface circuit; when the device receives information, it inputs information to the chip's interface circuit.

[0295] The method steps in the embodiments of this application can be implemented in hardware or by a processor executing software instructions. The software instructions can consist of corresponding software modules, which can be stored in random access memory, flash memory, read-only memory, programmable read-only memory, erasable programmable read-only memory, electrically erasable programmable read-only memory, registers, hard disks, portable hard disks, compact disc read-only memory (CD-ROM), or any other form of storage medium known in the art. An exemplary storage medium is coupled to a processor, enabling the processor to read information from and write information to the storage medium. Of course, the storage medium can also be a component of the processor. The processor and storage medium can reside in an ASIC. Additionally, the ASIC can reside in a network device or terminal device. Alternatively, the processor and storage medium can exist as discrete components in the network device or terminal device.

[0296] In the above embodiments, implementation can be achieved entirely or partially through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented entirely or partially in the form of a computer program product. The computer program product includes one or more computer programs or instructions. When the computer program or instructions are loaded and executed on a computer, the processes or functions described in the embodiments of this application are performed entirely or partially. The computer can be a general-purpose computer, a special-purpose computer, a computer network, a network device, a user equipment, or other programmable device. The computer program or instructions can be stored in a computer-readable storage medium or transferred from one computer-readable storage medium to another. For example, the computer program or instructions can be transferred from one website, computer, server, or data center to another website, computer, server, or data center via wired or wireless means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available medium can be a magnetic medium, such as a floppy disk, hard disk, or magnetic tape; it can also be an optical medium, such as a digital video optical disc; or it can be a semiconductor medium, such as a solid-state drive. The computer-readable storage medium may be a volatile or non-volatile storage medium, or may include both types of storage media.

[0297] In the various embodiments of this application, unless otherwise specified or in case of logical conflict, the terminology and / or descriptions of different embodiments are consistent and can be referenced by each other. The technical features of different embodiments can be combined to form new embodiments according to their inherent logical relationship.

Claims

1. A data transmission method, characterized in that, The method includes: The relay device receives a first message from a remote device. The first message is used to discover the remote device or request to establish a communication connection with the relay device. The first message includes a relay service code, and the protocol data unit session parameters corresponding to the relay service code include a first parameter. The value of the first parameter is used to indicate the establishment of a protocol data unit session that supports hierarchical quality of service. The protocol data unit session is used to relay data from the remote device. The relay device sends a second message to the remote device. The second message is used to determine a first association between uplink data packets and a first type of quality of service flow. The first type of quality of service flow is used to transmit data between the relay device and the remote device. The first association is used to represent the association between uplink data packets of different importance and first type of quality of service flows of different quality of service levels. The relay device transmits data from the remote device through the protocol data unit session.

2. The method according to claim 1, characterized in that, The method further includes: The relay device receives configuration information from the first network device. The configuration information includes the relay service code and the protocol data unit session parameters corresponding to the relay service code, wherein the protocol data unit session parameters include the first parameter.

3. The method according to claim 1, characterized in that, The method further includes: The relay device sends a request message to the second network device to establish the protocol data unit session, the request message including the first parameter.

4. The method according to any one of claims 1 to 3, characterized in that, The method further includes: The relay device establishes multiple first-type quality of service flows with an association relationship, and the first-type quality of service flows are used to transmit data between the relay device and the remote device; The relay device establishes multiple Type II Quality of Service (QoS) flows with association relationships. These multiple Type II QoS flows are associated with the Protocol Data Unit (PDU) session and are used for data transmission between the relay device and the third network device. The relay device determines a second association between the plurality of first-type quality of service flows and the plurality of second-type quality of service flows.

5. The method according to claim 4, characterized in that, The method further includes: The relay device receives a first uplink data packet from the remote device through the quality of service flow identified by the first flow identifier, and maps the first uplink data packet to a first quality of service flow among the plurality of second-type quality of service flows according to the second association relationship; wherein, the first flow identifier is used to identify the quality of service flow carrying the first uplink data packet among the plurality of first-type quality of service flows; the second association relationship includes the association relationship between the first quality of service flow and the quality of service flow identified by the first flow identifier; The relay device sends the first uplink data packet to the third network device through the first quality of service flow.

6. The method according to claim 4, characterized in that, The method further includes: The relay device determines a third association between the plurality of first-type quality of service flows and the plurality of second-type quality of service flows.

7. The method according to claim 6, characterized in that, The method further includes: The relay device receives a first downlink data packet from the third network device through the quality of service flow identified by the second flow identifier, and maps the first downlink data packet to a second quality of service flow among the plurality of first-type quality of service flows according to the third association relationship; wherein, the second flow identifier is used to identify the quality of service flow carrying the first downlink data packet among the plurality of second-type quality of service flows; the third association relationship includes the association relationship between the second quality of service flow and the quality of service flow identified by the second flow identifier; The relay device sends the first downlink data packet to the remote device through the second quality of service flow.

8. The method according to claim 7, characterized in that, The method further includes: In the event of resource constraints between the remote device and the relay device, if the priority of the second quality of service flow is lower than a threshold, the relay device discards the second downlink data packets mapped to the second quality of service flow.

9. The method according to claim 4, characterized in that, The method further includes: The relay device receives a first connection message from the remote device. The first connection message is used to request the establishment of multiple first-type quality of service flows with an association relationship. The first connection message indicates the association relationship between the multiple first-type quality of service flows.

10. The method according to claim 4, characterized in that, The method further includes: The relay device receives a Protocol Data Unit (PDU) session modification message from the second network device, the PDU session modification message including the identification information of the remote device; The relay device establishes multiple Type I quality of service flows with correlation, including: The relay device establishes multiple Class I quality of service flows with an association with the remote device based on the protocol data unit session modification message.

11. The method according to claim 10, characterized in that, The method further includes: The relay device updates the second association and / or the third association.

12. The method according to claim 10, characterized in that, The method further includes: The relay device sends a second connection message to the remote device, the second connection message indicating the association between the plurality of first-type quality of service flows.

13. A data transmission method, characterized in that, The method includes: The remote device sends a first message to the relay device. The first message is used to discover the remote device or request to establish a communication connection with the relay device. The first message includes a relay service code. The protocol data unit session parameters corresponding to the relay service code include a first parameter. The value of the first parameter is used to indicate the establishment of a protocol data unit session that supports hierarchical quality of service. The protocol data unit session is used to relay data from the remote device. The remote device receives a second message from the relay device. The second message is used to determine a first association between uplink data packets and a first type of quality of service flow. The first type of quality of service flow is used to transmit data between the relay device and the remote device. The first association is used to represent the association between uplink data packets of different importance and first type of quality of service flows of different quality of service levels.

14. The method according to claim 13, characterized in that, The method further includes: The remote device receives configuration information from the first network device. The configuration information includes the relay service code and the protocol data unit session parameters corresponding to the relay service code, wherein the protocol data unit session parameters include the first parameter.

15. The method according to claim 13, characterized in that, The method further includes: The remote device determines that the first uplink data packet corresponds to a first flow identifier based on the attribute information of the first uplink data packet, combined with the first association relationship and the association relationship between multiple first-type quality of service flows; the attribute information includes one or more of a specific application identifier, a triple, and a quintuple; the first-type quality of service flow is used for data transmission between the relay device and the remote device; The remote device maps the first uplink data packet to one of the plurality of first-class quality of service flows identified by the first flow identifier; The remote device sends the first uplink data packet to the relay device through the quality of service flow identified by the first flow identifier.

16. The method according to claim 15, characterized in that, The method further includes: The remote device sends a first connection message to the relay device. The first connection message is used to request the establishment of multiple first-type quality of service flows with an association relationship. The first connection message indicates the association relationship between the multiple first-type quality of service flows.

17. The method according to claim 15, characterized in that, The method further includes: The remote device receives a second connection message from the relay device, the second connection message indicating the association between the plurality of first-class quality of service flows.

18. The method according to claim 15, characterized in that, The method further includes: When resources are limited between the remote device and the relay device, if the priority of the QoS flow identified by the first flow identifier is lower than a threshold, the second uplink data packet mapped to the QoS flow identified by the first flow identifier is discarded.

19. A communication device, characterized in that, It includes a module for performing the method as described in any one of claims 1 to 12, or includes a module for performing the method as described in any one of claims 13 to 18.

20. A communication device, characterized in that, The device includes a processor and an interface circuit. The interface circuit is used to receive signals from other communication devices besides the communication device and transmit them to the processor, or to send signals from the processor to other communication devices besides the communication device. The processor is used to implement the method as described in any one of claims 1 to 12, or to implement the method as described in any one of claims 13 to 18, through logic circuits or executing code instructions.

21. A computer-readable storage medium, characterized in that, The storage medium stores a computer program or instructions that, when executed by a communication device, implement the method as described in any one of claims 1 to 12, or the method as described in any one of claims 13 to 18.

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