Data processing method applicable to dual connectivity (DC) scenario

Abstract

The present application provides a communication method applicable to a dual connectivity (DC) scenario. The method comprises: a first network device and a second network device exchange congestion assistance information, and the first network device or the second network device comprehensively considers network congestion and determines to activate / deactivate a PSI-based discard of downlink data, or activate / deactivate a PSI-based discard of a UE. In the DC scenario, the method can coordinate the congestion capabilities of two network devices and thus better provide QoS guarantees for XR services.

Description

A data processing method applied to a dual connectivity (DC) scenario

[0001] The present application claims priority to the Chinese patent application No. 202410482074.7, filed on April 19, 2024, and entitled "A data processing method applied to a dual connectivity (DC) scenario", the whole content of which is incorporated herein by reference. TECHNICAL FIELD

[0002] The present application relates to the field of wireless communication, and more particularly, to a data processing method applied to a dual connectivity (DC) scenario. BACKGROUND

[0003] Extended reality (XR) refers to various types of environments that combine reality and virtuality generated by computing technology and wearable devices, as well as human-computer interaction, specifically including the following typical forms: augmented reality (AR), mixed reality (MR), and virtual reality (VR).

[0004] 5G system is based on the granularity of quality of service flow (QoS flow) to forward and process data, and guarantee the quality of service (QoS). The 5G core network (5GC) in the 5G system indicates the QoS requirements of different QoS flows to the radio access network (RAN) through a QoS profile. For general services of the 5G system, only the granularity of protocol data unit (PDU) is required for QoS guarantee, but for XR services, it is usually expected to require QoS guarantee in the granularity of PDU set. A QoS flow is configured with PDU set integrated handling information (PSIHI), and the entire PDU set can be processed as a whole. If a PDU in the PDU set is lost, the remaining PDU packets in the PDU set can be considered as no longer needed by the XR service, and the remaining PDU data in the PDU set can be discarded to release wireless resources. When the network is congested, the unimportant packets can be discarded based on the importance of the protocol data unit set (PSI) to alleviate network congestion. In the dual-connectivity (DC) scenario, it is a technical problem to be solved to coordinate the PDU set processing capability and the processing of PDU set packets of two network devices, and the two network devices jointly guarantee the QoS of the XR service. SUMMARY

[0005] The present application provides a communication method applied to a dual connectivity (DC) scenario. In the DC scenario, the method can enable an access network device, including a master node (MN) and a secondary node (SN), to correctly process data packets of an XR service, guarantee the QoS of the XR service, and improve the service experience.

[0006] In a first aspect, a communication method applied to a dual connectivity (DC) scenario is provided. The method comprises: receiving, by a first network device, assistance information sent by a second network device, the assistance information being used to feed back a radio resource congestion state of the second network device, and the assistance information can comprise one or more of the following: an activation / deactivation suggestion of PSI-based discard; a congestion state of the network device; a congestion level of the network device; an air interface rate that can be supported by the network device, and the like. Based on the assistance information, the first network device performs one or more of the following operations: instructing a user equipment (UE) to activate / deactivate PSI-based discard; activating / deactivating downlink PSI-based discard; adjusting a split ratio of a split bearer; feeding back congestion information to a core network; adding an explicit congestion notification (ECN) in a data packet.

[0007] In combination with the first aspect, the first network device determines a congestion state condition of the first network device and the second network device, and the congestion state condition comprises:

[0008] a first condition: the first network device is congested, and the second network device is congested;

[0009] a second condition: the first network device is congested, or the second network device is congested;

[0010] a third condition: the first network device is not congested, or the second network device is not congested;

[0011] a fourth condition: the first network device is not congested, and the second network device is not congested;

[0012] According to the first condition or the second condition, the UE is instructed to activate PSI-based discard; and according to the third condition or the fourth condition, the UE is instructed to deactivate PSI-based discard.

[0013] In combination with the first aspect, the assistance information is carried in an Xn interface message or a protocol data unit (PDU) header.

[0014] In combination with the first aspect, the first network device is a master node (MN) in the DC scenario, and the second network device is a secondary node (SN) in the DC scenario; or the first network device is the SN in the DC scenario, and the second network device is the MN in the DC scenario.

[0015] In the above scheme, the two network devices constituting the DC can update and interact the congestion information in time, and one of the network devices comprehensively considers the congestion conditions between the two network devices to determine a network congestion relief action, so that the processing between the two network devices is consistent, and the QoS of the XR service is guaranteed.

[0016] In a second aspect, a method for two network nodes to interact PDU set processing capability is provided. The method comprises: a first network device receiving a PDU packet from a core network, the PDU packet carrying an end of data burst indication, the end of data burst indication indicating that the data burst is transmitted completely; and sending the end of data burst indication to a second network device.

[0017] In combination with the second aspect, the sending of the end of data burst indication to the second network device can be achieved by one or more of the following methods: forwarding the PDU packet received from the core network, the PDU packet carrying the end of data burst indication; adding the end of data burst indication in the PDU packet forwarded to the second network device; and sending an empty PDU packet carrying the end of data burst indication to the second network device.

[0018] It should be understood that the second aspect has similar advantages as the first aspect, which will not be repeated here.

[0019] In a third aspect, another method for two network nodes to interact packet loss information in a handover scenario is provided. For a downlink data transmission scenario, the method comprises: a third network device sending a PDCP packet loss report to a UE, the PDCP packet loss report indicating that a first PDU or a first PDU set is discarded; the third network device sending a handover command to the UE, the handover command indicating that the UE is to be handed over from the third network device to a fourth network device; the UE being handed over to the fourth network device after receiving the handover command; the UE sending first status information to the fourth network device, the first status information indicating that the first PDU or the first PDU set has been received or acknowledged.

[0020] For uplink data, the method comprises: the UE sending a PDCP packet loss report to the third network device, the PDCP packet loss report indicating that a second PDU or a second PDU set is discarded; the third network device sending a handover command to the UE, the handover command indicating that the UE is to be handed over from the third network device to the fourth network device; the UE being handed over to the fourth network device after receiving the handover command; the third network device sending second status information to the fourth network device, the second status information indicating that the second PDU or the second PDU set has been received or acknowledged; the third network device forwarding uplink data of the UE to the fourth network device; the fourth network device confirming that the second PDU or the second PDU set is not included in the uplink data forwarded by the third network device; the fourth network device considering that the second PDU or the second PDU set has been received or discarded; and the fourth network device not starting a reordering timer for the second PDU or the second PDU set.

[0021] In the fourth aspect, the fourth network device can send a third status report to the UE, indicating that the second PDU or the second PDU set has been received or acknowledged. When the UE or the network device receives the PDCP packet loss report, for the data packet indicated as discarded, if the UE or the network device has received it, the indication in the packet loss report is ignored. When the UE or the network device receives the data packet, and the data packet has been indicated as discarded in the PDCP packet loss report, the UE or the network device saves the data packet and delivers it to the upper layer after processing.

[0022] In the fifth aspect, the present application provides a processor for executing the method provided in any one of the implementation manners of the first aspect to the fourth aspect. In the process of executing the method, the process of sending the information and the process of obtaining / receiving the information in the method can be understood as the process of outputting the information by the processor and the process of receiving the input information by the processor. When the information is outputted, the processor outputs the information to an interface, and transmits the information through the interface. After the information is outputted by the processor, the information can be further processed before reaching the interface. Similarly, when the processor receives the input information, the interface obtains / receives the information and inputs the information to the processor. Furthermore, after the interface receives the information, the information can be further processed before being inputted to the processor.

[0023] For the operations of transmitting, sending and obtaining / receiving, if no special description is given, or if it does not conflict with the actual role or internal logic in the related description, it can be understood as the operations of outputting and receiving, inputting, and the operations of transmitting, sending and receiving performed by the radio frequency circuit and the antenna, which are not limited in the present application.

[0024] In the implementation process, the processor can be a processor specially used for executing the method, or a processor executing the computer program or instructions in the memory to execute the method, such as a general processor. The memory can be a non-transitory memory, such as a read only memory (ROM), which can be integrated on the same chip as the processor, or can be separately arranged on different chips, and the type of the memory and the arrangement mode of the memory and the processor are not limited in the embodiments of the present application.

[0025] In the sixth aspect, a computer readable storage medium is provided, which stores program codes for execution by a device, and the program codes include codes for executing the method provided in any one of the implementation manners of the first aspect to the third aspect.

[0026] In a seventh aspect, a computer program product including instructions, which, when executed on a computer, cause the computer to perform the method provided by any of the implementations of the first aspect to the third aspect.

[0027] In an eighth aspect, a chip is provided, which includes a processor and a communication interface. The processor reads instructions stored on a memory through the communication interface, and executes the method provided by any of the implementations of the first aspect to the third aspect.

[0028] Optionally, as an implementation form, the chip can further include a memory, and the memory stores a computer program or instructions. The processor is configured to execute the computer program or instructions stored on the memory, and when the computer program or instructions are executed, the processor is configured to execute the method provided by any of the implementations of the first aspect to the third aspect. BRIEF DESCRIPTION OF DRAWINGS

[0029] FIG. 1 is a schematic diagram of a system architecture provided by an embodiment of the present application.

[0030] FIG. 2 is a schematic diagram of a 5G system based on a QoS architecture provided by an embodiment of the present application.

[0031] FIG. 3 is a schematic diagram of a control plane architecture in an MR-DC scenario.

[0032] FIG. 4 is a schematic block diagram of a terminal device (e.g., UE) supporting EN-DC.

[0033] FIG. 5 is a schematic block diagram of a terminal device (e.g., UE) supporting MR-DC.

[0034] FIG. 6 is a schematic block diagram of an MR-DC architecture supporting multiple types of bearers.

[0035] FIG. 7 is a schematic flowchart of a communication method applied to a dual connectivity (DC) scenario provided by an embodiment of the present application.

[0036] FIG. 8 is a schematic flowchart of interaction of two network devices for auxiliary information in a dual connectivity (DC) scenario provided by an embodiment of the present application.

[0037] FIG. 9 is a schematic flowchart of downlink packet loss data indication in a handover scenario provided by an embodiment of the present application.

[0038] FIG. 10 is a schematic flowchart of uplink packet loss data indication in a handover scenario provided by an embodiment of the present application.

[0039] FIG. 11 is a schematic block diagram of a communication apparatus provided by an embodiment of the present application.

[0040] FIG. 12 is a schematic diagram of another communication apparatus provided by an embodiment of the present application.

[0041] FIG. 13 is a schematic diagram of a chip system according to an embodiment of the present application. DETAILED DESCRIPTION

[0042] The technical solutions in the present application will be described below with reference to the drawings.

[0043] First, in the present application, "for indicating" can include for directly indicating and for indirectly indicating. When describing that certain indication information is for indicating A, it can include that the indication information directly indicates A or indirectly indicates A, and does not mean that A must be carried in the indication information.

[0044] The information indicated by the indication information is referred to as to-be-indicated information, and there are many ways to indicate the to-be-indicated information in the specific implementation process, for example, but not limited to, the to-be-indicated information can be directly indicated, such as the to-be-indicated information itself or the index of the to-be-indicated information. The to-be-indicated information can also be indirectly indicated by indicating other information, where the other information and the to-be-indicated information have an association relationship. The to-be-indicated information can also be only indicated in part, and the other part of the to-be-indicated information is known or agreed in advance. For example, the indication of a specific information can also be achieved by means of the arrangement order of each information agreed in advance (for example, the protocol stipulates), thereby reducing the indication overhead to a certain extent. At the same time, the common part of each information can be identified and uniformly indicated to reduce the indication overhead caused by separately indicating the same information.

[0045] Second, in the present application, "at least one" means one or more, and "multiple" means two or more. In addition, in the embodiments of the present application, "first", "second", and various numerical numbers (for example, "#1", "#2", etc.) are only for the convenience of description and do not limit the scope of the embodiments of the present application. The size of the serial number of each process below does not mean the execution order, and the execution order of each process should be determined according to its function and inherent logic, and should not constitute any limitation on the implementation process of the embodiments of the present application. It should be understood that the objects thus described can be interchanged under appropriate circumstances, so as to be able to describe solutions other than the embodiments of the present application. In addition, in the embodiments of the present application, "S210" and the like are only for the convenience of description and do not limit the order of execution steps.

[0046] Third, in the embodiments of the present application, the words "exemplary" or "for example" are used to mean serving as an example, instance, or illustration. Any embodiment or design described as "exemplary" or "for example" in the present application should not be construed as being more preferred or advantageous than other embodiments or designs. Rather, the use of the words "exemplary" or "for example" is intended to present concepts in a concrete manner.

[0047] Fourthly, the "storing" in the embodiments of the present application can refer to storing in one or more memories. The one or more memories can be separately arranged or integrated in the encoder or decoder, processor, or communication device. The one or more memories can be partially separately arranged and partially integrated in the decoder, processor, or communication device. The memory can be any form of storage medium, and the present application does not limit the memory.

[0048] Fifthly, in the embodiments of the present application, the "protocol" can refer to a standard protocol in the communication field, which can include the NR protocol and related protocols applied to future communication systems, and the present application does not limit the protocol.

[0049] Sixthly, in the embodiments of the present application, "of", "corresponding", "relevant", "corresponding", and "associated" can be used interchangeably. It should be pointed out that when the distinction is not emphasized, the meanings expressed are consistent.

[0050] Seventhly, in the embodiments of the present application, "in the case of", "when", and "if" can be used interchangeably. It should be pointed out that when the distinction is not emphasized, the meanings expressed are consistent.

[0051] Eighthly, the term "and / or" in the present application only describes the association relationship between the associated objects, which means that there can be three relationships, for example, A and / or B can mean that A exists alone, A and B exist together, and B exists alone. In addition, the character " / " in the present application generally represents an "or" relationship between the associated objects.

[0052] In order to facilitate the description, the system architecture of the embodiments of the present application is described in detail below.

[0053] The technical solutions of the embodiments of the present application can be applied to various communication systems, for example: a global system of mobile communication (GSM) system, a code division multiple access (CDMA) system, a wideband code division multiple access (WCDMA) system, a general packet radio service (GPRS), a long term evolution (LTE) system, an LTE frequency division duplex (FDD) system, an LTE time division duplex (TDD), a universal mobile telecommunication system (UMTS), a worldwide interoperability for microwave access (WiMAX) communication system, a 5th generation (5G) mobile communication system or a new radio (NR), and a future evolved communication system, etc., and the present application is not limited thereto. The 5G mobile communication system can be a non-standalone (NSA) or standalone (SA).

[0054] The technical solutions provided in the application can also be applied to machine type communication (MTC), long term evolution-machine (LTE-M), device-to-device (D2D) network, machine to machine (M2M) network, internet of things (IoT) network or other network. The IoT network may, for example, include a vehicle network. In the vehicle network system, the communication modes are collectively referred to as vehicle to X (V2X, X can represent any thing), for example, the V2X can include vehicle to vehicle (V2V) communication, vehicle to infrastructure (V2I) communication, vehicle to pedestrian (V2P) communication or vehicle to network (V2N) communication, and the like.

[0055] In the embodiments of the present application, the terminal device can also be referred to as a user equipment (UE), a mobile station (MS), a mobile terminal (MT), etc., and refers to a device that provides voice and / or data connectivity to a user. For example, the terminal device can be a mobile phone, a tablet computer, a computer with wireless transceiver function, a mobile internet device (MID), a wearable device, a virtual reality (VR) terminal device, an augmented reality (AR) terminal device, a wireless terminal in industrial control, a wireless terminal in self driving, a wireless terminal in remote medical treatment, a wireless terminal in smart grid, a wireless terminal in transportation safety, a wireless terminal in smart city, a wireless terminal in smart home, a drone, a drone controller, etc. The embodiments of the present application do not limit the application scenarios. The terminal device also includes a device capable of sidelink (sidelink) communication, such as a vehicle terminal, or a handheld terminal capable of V2X (vehicle-to-everything) communication, etc. For the convenience of description, the terminal device will be described below by taking a terminal or a UE as an example.

[0056] The access network device refers to a radio access network (RAN) node (or device) that accesses a terminal to a wireless network, which can also be referred to as a base station, for example, an NR gNB, an LTE eNB, and various types of base stations. For ease of description, the embodiments of the present application uniformly refer to the "access network device" as "base station". Among them, the NR gNB can adopt a centralized unit (CU) and distributed unit (DU) separated architecture, such as the base station #1 shown in FIG. 1, the CU and the DU are connected through the F1 interface for message transmission; or can adopt a CU and DU integrated architecture, such as the base station #2 shown in FIG. 1, the embodiments of the present application do not limit it. In the scenario of separate deployment of the access network device including the CU and the DU, the CU supports radio resource control (RRC), packet data convergence protocol (PDCP), service data adaptation protocol (SDAP), and other protocols; the DU mainly supports radio link control (RLC), media access control (MAC), and physical layer protocols. In the dual connectivity (DC) scenario, the terminal device can be connected to two base stations at the same time, one of which serves as a control anchor point to provide control plane connection and user plane connection for the terminal, referred to as the master base station, and the other only provides user plane connection for the terminal, referred to as the secondary base station.

[0057] The core network device refers to a device in the core network (CN) that provides service support for the terminal. At present, some examples of core network devices are: access and mobility management function (AMF) entity, session management function (SMF) entity, user plane function (UPF) entity, and the like, which are not listed one by one here. Among them, the AMF entity can be responsible for access management and mobility management of the terminal; the SMF entity can be responsible for session management, such as session establishment of the user; the UPF entity can be a functional entity of the user plane, mainly responsible for connecting external networks. It should be noted that the entity in the present application can also be referred to as a network element or a functional entity, for example, the AMF entity can also be referred to as an AMF network element or an AMF functional entity, and for example, the SMF entity can also be referred to as an SMF network element or an SMF functional entity.

[0058] The network device provides services for a cell, and a terminal device communicates with the cell through a transmission resource (for example, a frequency domain resource, or a spectrum resource) allocated by the network device. The cell can belong to a macro base station (for example, a macro eNB or a macro gNB) or a base station corresponding to a small cell. The small cell can include a metro cell, a micro cell, a pico cell, a femto cell, and the like. The small cell has a small coverage range and low transmission power, and is suitable for providing a high-rate data transmission service.

[0059] In this application, the device for implementing the function of the access network device can be the access network device, or can be a device capable of supporting the access network device to implement the function, such as a chip system, a hardware circuit, a software module, or a hardware circuit plus a software module. The device can be installed in the access network device or can be used in matching with the access network device. In the technical solutions provided in this application, the device for implementing the function of the access network device is the access network device, and the access network device is taken as an example of a base station to describe the technical solutions provided in this application.

[0060] In the embodiments of this application, one network device can include one or more cells, and each cell includes one or more transmission reception points (TRPs) or transmission points (TPs).

[0061] In order to facilitate understanding of the solutions of the embodiments of this application, the technical terms related to the embodiments of this application will be described in detail.

[0062] 1. PDU set

[0063] A set of multiple data packets in the transmission layer corresponds to the minimum granularity of application layer data processing. In some application scenarios, the application layer can correctly parse the corresponding data unit only after correctly receiving all data packets of a PDU set. In other application scenarios, the application layer can correctly parse the corresponding data unit after correctly receiving a certain proportion of data packets in the PDU set.

[0064] 2. XR service

[0065] Extended Reality (XR) refers to various types of reality and virtuality combined environments generated by computing technology and wearable devices, as well as human-computer interaction. XR specifically includes the following typical forms: AR, VR and Mixed Reality (MR).

[0066] The 3rd generation partnership project (3GPP) Rel-17 models and analyzes the service characteristics of XR. Generally, XR services periodically generate data frames at a certain frame rate. Taking an AR service with a frame rate of 60 frames per second (fps) as an example, 60 video images are generated per second, and a video frame occurs approximately every 16.67 ms. A video frame can be transmitted by multiple data packets, which can be divided into one or more PDU sets.

[0067] 3. Quality of Service (QoS)

[0068] Quality of Service refers to a technology used to solve network delay and congestion problems. When the network is congested, data may be discarded. In order to meet the requirements of different applications for different QoS, the network needs to allocate and schedule resources according to the requirements of users, and provide different QoS for different data.

[0069] 4. QoS Flow (QoS Flow)

[0070] The 5G system transmits and processes data based on the granularity of QoS flow and guarantees its QoS.

[0071] The 5G core network establishes one or more protocol data unit sessions (PDU sessions) for a UE, and a QoS flow is a data flow with the same source and destination address and the same QoS requirement in a PDU session. FIG. 2 is a schematic diagram of a 5G system based on a QoS architecture according to an embodiment of the present application. As shown in FIG. 2, a PDU session is established between a UE and a UPF, a wireless bearer is established between the UE and the NB, a core network tunnel is established between the NB and the UPF, and the PDU session includes multiple QoS flows, including a first QoS flow, a second QoS flow, and the like.

[0072] For downlink, 5GC maps data packets with the same characteristics, including source internet protocol (IP) address, destination IP address, source port number, destination port number and transport layer protocol number, into the same QoS flow by identifying the characteristics of the data packets, and carries QoS flow ID (QFI) in the data packet header to identify which QoS flow the data packet belongs to. For uplink, 5GC can display or implicitly configure the mapping relationship between the above data packet characteristics and QoS flow to UE, and UE maps uplink data to be transmitted into different QoS flows.

[0073] Data of different QoS flows are independent of each other when transmitted in the 5G system. For each QoS flow, 5GC sends its QoS profile to the radio access network (RAN) to indicate its QoS requirements, such as packet delay budget (PDB) and packet error rate (PER), which represent the quality of service expected to be obtained by the data of the QoS flow when transmitted in the 5G system. PDB represents the upper limit of the transmission delay of data packets between the core network and the UE, and data packets that fail to be correctly transmitted within the PDB are considered to have timed out. PER represents the upper limit of the packet error rate during the transmission of the QoS flow, i.e., the proportion of data packets that are processed by the sending end but not correctly received by the receiving end. Specifically, the core network and the UE can be understood as follows: for downlink behavior, it can be understood as starting from the UPF of the core network to the UE; for uplink behavior, it can be understood as starting from the UE to the UPF of the core network.

[0074] For a PDU session, RAN establishes one or more data radio bearers (DRBs) for it, and maps each QoS flow to the DRBs for air interface transmission. Multiple QoS flows can be mapped to one DRB, but one QoS flow cannot be mapped to multiple DRBs. QoS flows with the same or similar QoS requirements are usually mapped to the same DRB, thereby providing the same QoS guarantee in the air interface.

[0075] 5. QoS parameters of PDU

[0076] 5GC indicates the QoS requirements of different QoS flows to RAN through QoS profile, which are reflected by various QoS parameters. For example, common QoS parameters include PDB, PER, etc. The transport network should try its best to guarantee the QoS requirements of services to guarantee the user's service experience.

[0077] 6. QoS parameters of PDU set

[0078] XR services usually expect to require QoS guarantee at the granularity of PDU set, which is determined by the encoding mode of XR services. Since a PDU set corresponds to the smallest unit of application layer data processing, for example, a video frame, for many applications, only when all the data packets of the PDU set are correctly received, the receiving side can successfully decode the video frame. Therefore, XR services need the transport network to provide overall QoS guarantee for the PDU set, to avoid partial data packets in the PDU set from causing the entire video frame decoding failure due to timeout or error.

[0079] 3GPP R18 (Release-18) designs new QoS parameters for XR services, called PDU set QoS parameters, including PDU set delay budget (PSDB), PDU set error rate (PSER) and PDU set integrated information (PSIHI). PSDB and PSER correspond to the traditional PDB and PER respectively. PSDB represents the upper limit of the time delay from the transmission of the first data packet in the PDU set between the core network and the UE to the completion of the transmission of the last data packet in the PDU set between the core network and the UE, i.e. the upper limit of the transmission time delay of the PDU set between the core network and the UE. The PDU set that fails to be completely and correctly transmitted within PSDB is considered to be timed out. PSER represents the upper limit of the proportion of the number of PDU sets that fail to be correctly transmitted in the transmission process of the QoS flow, i.e. the upper limit of the proportion of the PDU sets that are processed by the sending end but not correctly received by the receiving end. PSIHI is a description of whether the PDU set integrity is required for the QoS flow, which indicates whether the receiving side correctly receives all the data packets in the PDU set when the application layer processes the PDU set. This is related to the specific implementation of the application.

[0080] In one implementation, an application can only decode a PDU set correctly if all the packets in the PDU set are correctly received. In this case, the transport network should try its best to ensure that all the packets in a PDU set are correctly transmitted within the delay budget when transmitting the PDU set, because once a packet is lost or timed out, the application layer at the receiving end cannot process the PDU set in time, resulting in a degraded user experience. If it is determined that one packet in the PDU set cannot be correctly transmitted in time, the sending side can also give up transmitting the remaining packets, because even if the remaining packets are correctly transmitted, the application cannot process them, and actively giving up can save network resources. In another implementation, an application can decode a PDU set without correctly receiving all the packets in the PDU set, for example, when the PDU set is processed by redundancy coding at the sending side, and the receiving side can recover the data of the PDU set completely as long as it receives a certain number or proportion of the packets. In this case, even if some packets in the PDU set have been lost or timed out, the sending side should still continue to transmit the remaining packets, because they are still useful to the application layer.

[0081] Through the PDU set QoS parameter, the core network requires the RAN to provide PDU set granularity QoS guarantee for the PDU set-based QoS flow (such as XR service), so as to improve the satisfaction of XR users.

[0082] 7. Data discard based on protocol data unit set importance (PSI) (PSI based discard)

[0083] PSI based data discard refers to data discard by a terminal device according to the importance of data. A QoS flow is configured with PDU set integrated handling information (PSIHI), and the entire PDU set can be processed as a whole. If one PDU in the PDU set is lost, the remaining PDU packets in the PDU set can be considered as no longer needed by the XR service, and the remaining PDU data in the PDU set can be discarded to release wireless resources.

[0084] For uplink, the terminal device can be configured to perform PSI based data discard for specific DRB, and the network device can instruct the terminal to activate PSI based discard using MAC CE when network congestion occurs, and also instruct the terminal to deactivate PSI based discard using MAC CE when network congestion is alleviated. The terminal device connects to a network device, which sends configuration information to the terminal device, which is used to configure discard timer with short value (short duration data discard timer) and discard timer with long value (long duration data discard timer). The terminal device receives the activation command or deactivation command of the PSI based discard of the network device, and according to the activation command, determines to start the corresponding discard timer with short value, or according to the deactivation command, starts the corresponding discard timer with long value. After the timer expires, the terminal device discards the corresponding received data in the PDCP entity.

[0085] For downlink, the network device itself decides whether to instruct PSI based discard based on PSI, PSIHI, PSDB and other parameters.

[0086] 8. PDCP packet loss report

[0087] When the sending side PDCP entity discards part of the data packets (for example, discards data packets with PDCP sequence number (SN) 3 and 4), if the receiving side PDCP entity has not successfully received these data packets, when the receiving side PDCP entity receives data packets located after these data packets (for example, receives a data packet with PDCP SN 5), a sequence number gap (SN gap) will occur in the receiving side PDCP receiving window. At this time, the receiving side PDCP entity starts a reordering timer, expecting to receive data packets 3 and 4 within the timer time, and will not submit data packet 5 to the upper layer until the reordering timer expires or data packets 3 and 4 are received. Since the sending side has discarded data packets 3 and 4, the receiving side can only wait for the data packets to time out, which causes additional waiting delay for data packet 5.

[0088] To solve the above problem, after the sending side PDCP entity discards the data packets, it can actively send a PDCP packet loss report to the receiving side, indicating the SN of the discarded data packets, so that the receiving side knows that these data packets have been discarded, and when it finds that these data packets cause an SN gap, it does not start a reordering timer for them, and does not continue to wait for the discarded data packets, so that the subsequent data can be timely submitted to the upper layer.

[0089] Figure 1 is a schematic diagram of a communication system to which embodiments of the application can be applied. As shown in Figure 1, the communication system can comprise at least one terminal device; the communication system can also comprise at least two network devices, such as base station #1 and base station #2 shown in Figure 1. The terminal device can communicate with base station #1 and base station #2 simultaneously. As an example, the terminal device and base station #1, and the terminal device and base station #2 can communicate via wireless links. Each of the communication devices, such as the terminal device, base station #1 or base station #2, can be equipped with multiple antennas. For each of the communication devices in the communication system, the multiple antennas can comprise at least one transmit antenna for transmitting signals and at least one receive antenna for receiving signals. Therefore, each of the communication devices in the communication system, the terminal device and base station #1, and the terminal device and base station #2 can communicate via multiple antenna technology.

[0090] It should be understood that Figure 1 is a simplified schematic diagram for the purpose of illustration only, and that other network devices or other terminal devices can be included in the communication system, which are not shown in Figure 1.

[0091] It should also be understood that the terminal device communicating with base station #1 and base station #2 simultaneously can also be referred to as multi-radio dual-connectivity (MR-DC) of the terminal device. One of the network devices communicating with the terminal device can be referred to as a master node (MN), and the other network device communicating with the terminal device can be referred to as a secondary node (SN). As an example, it is assumed that base station #1 is the MN and base station #2 is the SN.

[0092] As an example, according to the different types of MN and SN, the MR-DC scenario can be further divided into EN-DC, NR-DC and NE-DC. As an example, when the MR-DC scenario is provided herein, the specific dual connectivity type is not limited, which can be EN-DC, NR-DC, NE-DC and other subsequent evolved dual connectivity types.

[0093] As an example, Figure 3 is a schematic diagram of a control plane architecture supporting MR-DC. In the MR-DC scenario, the access network device is connected to the core network through the MN, and the MN and the SN exchange relevant information of the control plane through the Xn interface.

[0094] The EN-DC and NR-DC will be described in detail below.

[0095] 1. EN-DC

[0096] EN-DC refers to LTE and 5G dual connectivity. The letter E stands for evolved universal terrestrial radio access new radio (E-UTRA), which is the air interface in LTE cellular networks. The letter N stands for new radio (NR), which is a global standard for a unified, more capable 5G wireless air interface. That is, a terminal device supporting EN-DC can be connected to both LTE master node eNB (MN-eNB) and 5G-NR secondary node gNB (SN-gNB) at the same time. EN-DC is a technology that can introduce 5G services and data rates in a 4G-dominant network.

[0097] For example, FIG. 4 is a schematic block diagram of a terminal device (e.g., UE) supporting EN-DC. As shown in FIG. 4, the bearers in the network can be divided into three categories: master cell group (MCG) bearers, secondary cell group (SCG) bearers, and Split bearers. In EN-DC, MCG bearers use PDCP, RLC, and MAC corresponding to the master node. For EN-DC, 4G (E-UTRA) is the master node, and therefore, MCG bearers use E-UTRA PDCP, E-UTRA RLC, and E-UTRA MAC. SCG bearers use PDCP, RLC, and MAC corresponding to the secondary node. For EN-DC, 5G-NR (gNB) is the secondary node, and therefore, SCG bearers use NR PDCP, NR RLC, and NR MAC. Split bearers split the air interface data into two bearers. In PDCP, NR PDCP is used. In RLC, E-UTRA RLC is used for bearers of MN air interface data, and NR RLC is used for bearers of SN air interface data. In MAC, E-UTRA MAC is used for bearers of MN air interface data, and NR MAC is used for bearers of SN air interface data.

[0098] It should be understood that the LTE master node eNB (MN-eNB) uses multiple different frequency points to form a multi-layer cell network, and these cells can all serve as control plane anchor points, so these 4G cells are collectively referred to as MCG, and the wireless data bearers established on top of them are referred to as MCG bearers. Correspondingly, multiple 5G cells form an SCG, and the wireless data bearers established on top of them are referred to as SCG bearers. Split bearers refer to splitting the air interface data into two bearers.

[0099] 2. NR-DC

[0100] NR-DC refers to 5G and 5G dual connectivity. A terminal device supporting MR-DC can be connected to a 5G-NR master node gNB (MN-gNB) and a 5G-NR secondary node gNB (SN-gNB) at the same time. Further, the UE can also be connected to a gNB which can simultaneously act as a master node MN and a secondary node SN, and configure MCG and SCG.

[0101] For example, FIG. 5 is a schematic block diagram of a terminal device (e.g., UE) supporting MR-DC. As shown in FIG. 5, the bearers in the network can be classified into three categories: master cell group (MCG) bearers, secondary cell group (SCG) bearers, and Split bearers. In MR-DC, the MN-gNB is the master node, and the MCG bearers use NR PDCP, MN RLC, and MN MAC; the SN-gNB is the secondary node, and the SCG bearers use NR PDCP, SN RLC, and SN MAC. The Split bearers split the air interface data into two bearers, use NR PDCP at PDCP, use MN RLC for the air interface data of the MN in RLC, use SN RLC for the air interface data of the SN, use MN MAC for the air interface data of the MN in MAC, and use SN MAC for the air interface data of the SN.

[0102] For example, FIG. 6 is a schematic diagram of MR-DC architecture supporting multiple bearer types. The multiple bearer types supported under MR-DC can include:

[0103] MCG bearers terminated at the MN (MN terminated MCG bearer);

[0104] SCG bearers terminated at the MN (MN terminated SCG bearer);

[0105] Split bearers terminated at the MN (MN terminated split bearer);

[0106] MCG bearers terminated at the SN (SN terminated MCG bearer);

[0107] SCG bearers terminated at the SN (SN terminated SCG bearer);

[0108] Split bearers terminated at the SN (SN terminated split bearer).

[0109] Among them, the MCG bearer refers to only involving the MCG side air interface resource, and the air interface resource mainly refers to the resource including the RLC / MAC / PHY layer. The SCG bearer refers to only involving the SCG side air interface resource, and the data plane radio bearer is only served by the SN. The split bearer refers to the MCG side air interface resource and the SCG side air interface resource, and the data plane radio bearer is served by the MN and the SN. The termination in the MN / SN refers to the PDCP entity in the MN or the SN.

[0110] As shown in FIG. 6, taking the following downlink data as an example, assuming that the MN is the anchor point, after receiving the data from the core network, for the split bearer, the downlink data is split from the PDCP layer and sent to the RLC / MAC of the MN and the SN respectively for processing. For example, the MN can send the downlink data to the terminal device through the MN RLC and the MN MAC layer in the MN, and also send the downlink data to the SN RLC in the SN, and send the downlink data to the terminal device through the SN RLC and the MN MAC layer in the SN.

[0111] At present, since the XR service requires QoS demand guarantee based on the granularity of PDU set, the corresponding base station needs to support PDU set-based data processing and forwarding. Further, in the downlink transmission process, when the QoS flow needs to be guaranteed based on the PDU set, and the base station supports PDU set processing, the core network adds the related information of the PDU set in the header of each data packet when transmitting the data packet to the base station. The related information can be a parameter for identifying the PDU set or reflecting the attribute of the PDU set, such as the PDU set sequence number, the sequence number of the PDU in the PDU set, the PDU set size, the PDU set importance, etc., so that the base station can distinguish which PDU set different data packets belong to. If the base station does not support PDU set processing, the core network does not need to add these information. Therefore, the core network needs to know the capability information of whether the base station supports PDU set processing. Specifically, if the QoS profile of the QoS flow contains the QoS parameter of the PDU set, the base station reports to the core network whether it supports processing the PDU set.

[0112] Further, the source base station supports processing PDU set, the core network adds the related information of the PDU set in the data packet sent to the source base station, and in the handover process, the source base station can carry the PDU set QoS parameter information of the QoS flow in the handover request message sent to the target base station. If the target base station supports the processing capability of the PDU set, the indication information is carried in the handover response message to the source base station. Further, the indication information can be a PDU Set based Handling Indicator information element, and the field is set to supported. The source base station judges whether the target base station supports the PDU set processing capability based on the received response message, and further processes the PDU set information based on the judgment. If the target base station supports the PDU set processing capability, the source base station carries the PDU set related information in the data forwarded to the target base station; otherwise, the source base station does not carry the PDU set related information in the data forwarded to the target base station, so as to avoid that the target base station cannot identify the PDU set related information.

[0113] For the MR-DC scenario, the MN has a control plane with the core network, and the control plane information of the SN is forwarded through the MN. The MN and the SN can be independent base station devices and can have different PDU set processing capabilities. When the MN receives the PDU set related information from the core network, if the SN does not support the PDU set processing capability, the PDU set related information provided by the core network cannot be recognized by the SN, resulting in that the XR service cannot be guaranteed in QoS and affecting user experience.

[0114] In the scenario where the PDCP entity is located in the MN, the QoS Flow data stream received from the core network first reaches the PDCP entity located in the MN, and then the data is processed by the PDCP entity of the MN. Processing the data can include forwarding the data by the MN according to the bearer type, etc. In the scenario where the PDCP entity is located in the SN, the QoS Flow data stream received from the core network first reaches the PDCP entity located in the SN, and then the data is processed by the PDCP entity of the SN. Processing the data can include forwarding the data by the SN according to the bearer type, etc.

[0115] For uplink service, after the access network device configures the UE with PSI-based discard, when the network is congested, the access network device can instruct the UE to activate PSI-based discard through MAC CE, instruct the UE to discard data packets with low importance to alleviate the network congestion state, and after the network congestion is alleviated, the access network device can instruct the UE to deactivate PSI-based discard through MAC CE. For a dual connectivity scenario, the master node MN and the secondary node SN each maintain their own congestion state, and both can issue activation / deactivation instructions to the UE through MAC CE. A mechanism needs to be designed to coordinate the activation / deactivation of PSI-based discard instructions between the master node MN and the secondary node SN.

[0116] FIG. 7 is a schematic flow chart of a communication method applied in a dual connectivity DC scenario according to an embodiment of the present application.

[0117] In this embodiment, the first network device and the second network device form a dual connectivity DC for the UE, the first network device can be a master node MN, and the second network device can be a secondary node SN; the first network device can also be a secondary node SN, and the second network device can be a master node MN. The first network device and the second network device can both include a centralized unit (CU) and a distributed unit (DU) separation architecture, wherein the CU can also include a centralized unit control plane (CU-CP) and a centralized unit user plane (CU-UP). Hereinafter, the network device can be a gNB alone, or a CU, or a DC, or a CU-CP, or a CU-UP, and no distinction is made. Hereinafter, no further description is given.

[0118] The first network device and the second network device can maintain their respective congestion states. Exemplarily, the congestion state can be {congested, not congested}. The initial congestion state of the network device can be "not congested". The first network device and the second network device can also give an activation / deactivation suggestion of PSI-based discard based on the congestion state. The activation suggestion of PSI-based discard is equivalent to the congestion state, and the deactivation suggestion of PSI-based discard is equivalent to the not congested state.

[0119] FIG. 8 is a schematic flow chart of interaction between two network devices for assisting information in a DC scenario.

[0120] The first network device and the second network device can also react to the congestion state of the network device through other auxiliary information. The auxiliary information can be that the CU of the first network device informs the DU of the first network device, or the DU of the second network device informs the CU of the second network device, and then the CU of the second network device forwards the auxiliary information to the CU of the first network device. The CU can be a CU-CP or a CU-UP. The above auxiliary information can include one or more of the following:

[0121] Activation / deactivation of the UE-based PSI discard suggestion;

[0122] Activation / deactivation of the downlink-based PSI discard suggestion;

[0123] The congestion state of the network device;

[0124] The congestion level of the network device;

[0125] The air interface rate that the network device can support, etc.

[0126] The second network device can actively update the above auxiliary information to the first network device when the auxiliary information changes, or update the above auxiliary information based on the update request of the first network device. The above auxiliary information can be transmitted through the Xn interface, or can be carried in the packet header forwarded by the network device to another network device.

[0127] In the CU and DU separation scenario, the DU of the first network device or the second network device can actively update the above auxiliary information to the CU of the first network device or the second network device through the F1 interface message, or update the above auxiliary information based on the request of the CU.

[0128] After receiving the auxiliary information, the first network device can execute one or more of the following methods based on the comprehensive congestion situation of the first network device and the second network device to relieve network congestion:

[0129] Indicating the UE to activate / deactivate the downlink-based PSI discard;

[0130] Activation / deactivation of the downlink-based PSI discard;

[0131] Adjusting the splitting ratio of the split bearer, for example, reducing the amount of split data of the network device on the congestion side;

[0132] Feedback of congestion information to the core network;

[0133] Adding an explicit congestion identifier (ECN) in the packet.

[0134] In the above method, optionally, the CU and DU separation scenario can instruct the UE to activate / deactivate the downlink PSI-based discard by the DU of the first network device; the activation / deactivation of the downlink PSI-based discard, or the adjustment of the split ratio of the separated bearer, or the feedback of the congestion information to the core network, or the addition of the explicit congestion notification (ECN) in the data packet can be performed by the CU or CU-CP of the first network device.

[0135] In the DC scenario, the network device that decides to configure the PSI-based discard for the UE is determined by the first network device or the second network device. The first network device can be the network device where the PDCP entity is located, or the network device without the PDCP entity.

[0136] For example, for the scenario where the bearer is terminated at the MN, the PDCP entity is located at the MN side, and whether to configure the PSI-based discard for the UE is decided by the master node MN or the secondary node SN; for the scenario where the bearer is terminated at the SN, the PDCP entity is located at the SN side, and whether to configure the PSI-based discard for the UE is decided by the secondary node SN or the master node MN.

[0137] For example, in the DC scenario, for the downlink PSI-based discard, when the network is congested, the network device can decide whether to perform the PSI-based discard by itself. For the scenario where the bearer is terminated at the MN, the PDCP entity is located at the MN side, and whether to perform the PSI-based discard on the downlink PDU set is decided by the master node MN or the secondary node SN; for the scenario where the bearer is terminated at the SN, the PDCP entity is located at the SN side, and whether to perform the PSI-based discard on the downlink PDU set is decided by the secondary node SN or the master node MN. The steps of the method described in the embodiment are described in detail below. In the embodiment of the present application, the first network device can be the master node MN or the secondary node SN:

[0138] S710, the first network device configures the PSI-based discard for the UE, and the configuration information can be sent to the UE through a radio resource control (RRC) message.

[0139] S720, optionally, the first network device notifies the second network device that the PSI-based discard has been configured for the UE through an Xn interface message.

[0140] Optionally, if the network device is a CU and DU separation architecture, the CU of the first network device notifies the CU of the second network device that the PSI-based discard has been configured for the UE through an Xn interface message.

[0141] Optionally, when the first network device is the MN, the Xn interface message can be an S-NODE ADDITION / MODIFICATION REQUEST message; when the first network device is the SN, the Xn interface message can be an S-NODE ADDITION / MODIFICATION REQUEST ACKNOWLEDGE or S-NODE MODIFICATION REQUIRED message.

[0142] The first network device and the second network device maintain respective congestion states, and the initial state of each is not congested.

[0143] Optionally, if the network device is of a CU and DU separated architecture, the DU can send the congestion state or the suggestion of activating / deactivating PSI-based discard to the CU, and the information can be transmitted through an F1 interface message or through a packet header of uplink data submitted by the DU to the CU.

[0144] S730. Optionally, when the congestion state of the second network device changes, for example, from not congested to congested, the second network device updates the assistance information to the first network device, which can help the first network device to learn the latest congestion state of the second network device.

[0145] The first network device can learn the congestion state condition of the first network device and the second network device constituting the DC, and the congestion state condition can be:

[0146] The first condition: the first network device is congested, and the second network device is congested.

[0147] The second condition: the first network device is congested, or the second network device is congested.

[0148] The third condition: the first network device is not congested, or the second network device is not congested.

[0149] The fourth condition: the first network device is not congested, and the second network device is not congested.

[0150] The congestion state condition in the above conditions can be comprehensively derived based on the assistance information.

[0151] S740. The first network device determines to activate the UE to perform PSI-based discard according to the congestion state condition of the first network device and the second network device, i.e., according to the first condition or the second condition, and sends the UE an indication information of activating PSI-based discard, which can be sent through a MAC CE. Optionally, the first network device can notify the second network device of the activation information through an Xn interface message.

[0152] S750, optionally, when the congestion state of the second network device changes, for example, from the congested state to the uncongested state, the second network device updates the assistance information to the first network device, which can assist the first network device to learn the latest congestion state of the second network device.

[0153] S760, the first network device determines to deactivate the UE to perform the PSI-based discard according to the congestion state condition of the first network device and the second network device, i.e., according to the third condition or the fourth condition, and sends the UE the deactivation indication information of the PSI-based discard, which is sent through the MAC CE.

[0154] S770, optionally, the first network device notifies the second network device of the deactivation information through the Xn interface message.

[0155] S780, optionally, when the congestion state of the first network device changes, for example, from the uncongested state to the congested state, the first network device updates the assistance information to the second network device, which can assist the second network device to learn the latest congestion state of the first network device.

[0156] The second network device can learn the congestion state condition of the first network device and the second network device constituting the DC.

[0157] S790, the second network device determines to activate the UE to perform the PSI-based discard according to the congestion state condition of the first network device and the second network device, i.e., according to the first condition or the second condition, and sends the UE the activation indication information of the PSI-based discard, which can be sent through the MAC CE. Optionally, the second network device can notify the first network device of the activation information through the Xn interface message.

[0158] S7100, optionally, when the congestion state of the first network device changes, for example, from the congested state to the uncongested state, the first network device updates the assistance information to the second network device, which can assist the second network device to learn the latest congestion state of the first network device.

[0159] S7110, the second network device determines to deactivate the UE to perform the PSI-based discard according to the congestion state condition of the first network device and the second network device, i.e., according to the third condition or the fourth condition, and sends the UE the deactivation indication information of the PSI-based discard, which is sent through the MAC CE.

[0160] S7120, optionally, the second network device notifies the first network device of the deactivation information through the Xn interface message.

[0161] Exemplarily, the first network device sends, to the UE, indication information of activating PSI-based discard according to a first condition, and the activation indication information can be sent through a MAC CE. Optionally, the first network device can notify the second network device of the activation information through an Xn interface message. After the congestion state is updated, the first network device sends, to the UE, indication information of deactivating PSI-based discard according to a third condition, and the deactivation indication information is sent through a MAC CE. Optionally, the first network device notifies the second network device of the deactivation information through an Xn interface message.

[0162] Exemplarily, the first network device sends, to the UE, indication information of activating PSI-based discard according to a first condition, and the activation indication information can be sent through a MAC CE. Optionally, the first network device can notify the second network device of the activation information through an Xn interface message. After the congestion state is updated, the first network device sends, to the UE, indication information of deactivating PSI-based discard according to a fourth condition, and the deactivation indication information is sent through a MAC CE. Optionally, the first network device notifies the second network device of the deactivation information through an Xn interface message.

[0163] Exemplarily, the first network device sends, to the UE, indication information of activating PSI-based discard according to a second condition, and the activation indication information can be sent through a MAC CE. Optionally, the first network device can notify the second network device of the activation information through an Xn interface message. After the congestion state is updated, the first network device sends, to the UE, indication information of deactivating PSI-based discard according to a third condition, and the deactivation indication information is sent through a MAC CE. Optionally, the first network device notifies the second network device of the deactivation information through an Xn interface message.

[0164] Exemplarily, the first network device sends, to the UE, indication information of activating PSI-based discard according to a second condition, and the activation indication information can be sent through a MAC CE. Optionally, the first network device can notify the second network device of the activation information through an Xn interface message. After the congestion state is updated, the first network device sends, to the UE, indication information of deactivating PSI-based discard according to a fourth condition, and the deactivation indication information is sent through a MAC CE. Optionally, the first network device notifies the second network device of the deactivation information through an Xn interface message.

[0165] Generally, XR service generates data frames periodically at a certain frame rate. One data frame can be transmitted by multiple data packets, which can be divided into one or more PDU sets. After the transmission of a data frame or a PDU set in a data period, the core network can indicate to the base station the end of a data burst or the end of a PDU set by adding indication information in the last data packet PDU of the data burst or the PDU set, which indicates the end of data transmission of the PDU set in the current period, so that the base station can instruct the UE to enter sleep after the end of the data burst, until the next data burst period arrives, thereby achieving the effect of UE energy saving. In a dual connectivity scenario, for a split bearer, only the network device where the PDCP entity is located can receive the indication information from the core network. The following provides a method for two network devices to interact with the data burst end information in a DC scenario.

[0166] S810, the first network device receives data packet carrying data burst end indication information (End of data burst) from the core network, the data burst indication information indicating the end of data transmission of the PDU set in the current period.

[0167] S820, the first network device sends the above-mentioned data burst end indication information (End of data burst) to the second network device. The above-mentioned indication information can be forwarded by directly forwarding the data packet carrying the data burst end indication information received from the core network, or the data burst end indication information (End of data burst) can be added in the data packet forwarded to the second network device, or an empty data packet can be sent to carry the data burst end indication information.

[0168] Optionally, in a CU and DU separation scenario, the CU or CU-UP of the first network device sends the data burst end indication information (End of data burst) to the CU or CU-UP of the second network device.

[0169] Optionally, in a CU and DU separation scenario, the CU of the first network device can also indicate the data burst end indication information (End of data burst) to the DU of the first network device. For example, the indication information can be carried in the last data packet of the data burst sent by the CU to the DU, or an empty data packet can be sent to carry the data burst indication information. Similarly, after the CU of the second network device receives the data burst end indication information (End of data burst), it can also indicate the DU of the second network device according to the above method.

[0170] When the network device where the PDCP entity is located changes, for example, the UE switches from a source base station to a target base station, for downlink, the UE sends a status report to the target base station, requesting the target base station to retransmit the data packets that the UE has not received, if some of the data packets have been discarded by the source station before the switching, the target station cannot obtain the data packets and cannot retransmit them. For uplink, the target station sends a status report to the UE, requesting the UE to retransmit the data packets that the base station has not received, if some of the data packets have been discarded by the UE before the switching, the UE cannot retransmit the data packets. The following provides a method for avoiding continuing to wait for retransmission of the discarded data packets before the switching after the switching.

[0171] FIG. 9 is a schematic flowchart of downlink packet loss data indication in a switching scenario according to an embodiment of the present application.

[0172] For a downlink data transmission scenario:

[0173] S910, the third network device sends a PDCP packet loss report to the UE, indicating that the first PDU or the first PDU set is discarded.

[0174] S920, the third network device sends a switching command, indicating that the UE switches from the third network device to a fourth network device. After receiving the switching command, the UE switches to the fourth network device.

[0175] S930, the UE sends first status information to the fourth network device, indicating that the first PDU or the first PDU set has been received or confirmed.

[0176] FIG. 10 is a schematic flowchart of uplink packet loss data indication in a switching scenario according to an embodiment of the present application.

[0177] For an uplink data transmission scenario:

[0178] S1010, the UE sends a PDCP packet loss report to the third network device, indicating that the second PDU or the second PDU set is discarded.

[0179] S1020, the third network device sends a switching command, indicating that the UE switches from the third network device to a fourth network device. After receiving the switching command, the UE switches to the fourth network device.

[0180] S1030, the third network device sends second status information to the fourth network device, indicating that the second PDU or the second PDU set has been received or confirmed.

[0181] S1040, the third network device forwards the uplink data of the UE to the fourth network device.

[0182] S1050, the fourth network device confirms that the uplink data forwarded by the third network device does not contain the second PDU or the second PDU set. The fourth network device considers that the second PDU or the second PDU set has been received or discarded, and the fourth network device does not start a reordering timer for the second PDU or the second PDU set.

[0183] Optionally, S1060, the fourth network device sends a third status report to the UE, indicating that the second PDU or the second PDU set has been received or confirmed.

[0184] When the UE or the network device receives the PDCP packet loss report, for the data packet indicated as discarded, if the UE or the network device has received it, the indication in the packet loss report is ignored.

[0185] When the UE or the network device receives a data packet that has been indicated as discarded by the PDCP packet loss report, the UE or the network device saves the data packet and delivers it to the upper layer after processing.

[0186] It should be understood that the size of the serial number of the above processes does not mean the order of execution. The execution order of each process should be determined according to its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0187] It should also be understood that in various embodiments of the present application, the terms and / or descriptions of different embodiments are consistent and can be mutually referred to if there is no special description and no logical conflict. The technical features in different embodiments can be combined to form new embodiments according to their inherent logical relationship.

[0188] It should also be understood that in some of the above embodiments, the main example is illustrated by taking the device in the existing network architecture as an example. It should be understood that the specific form of the device is not limited in the embodiments of the present application. For example, devices that can achieve the same function in the future are also applicable to the embodiments of the present application.

[0189] It can be understood that the methods and operations implemented by the devices (main node MN and secondary node SN) in the above various method embodiments can also be implemented by components (such as chips or circuits) that can be used for the devices.

[0190] It can also be understood that some optional features in various embodiments of the present application can not depend on other features in some scenarios, or can be combined with other features in some scenarios, without limitation.

[0191] Those skilled in the art should understand that, with the units and algorithm steps of the examples described in combination with the embodiments disclosed herein, the present application can be realized in the form of hardware or a combination of hardware and computer software. Whether a certain function is realized in the form of hardware or computer software driving hardware depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to realize the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0192] The following describes the communication apparatus provided by the embodiments of the present application in combination with FIG. 11 to FIG. 13. It should be understood that the description of the apparatus embodiments corresponds to the description of the method embodiments, and therefore, the content not described in detail can be referred to the method embodiments described above, and some content will not be described again for the sake of brevity.

[0193] The embodiments of the present application can divide the functional modules of the sending end device or the receiving end device according to the method examples described above, for example, each functional module can be divided according to each function, or two or more functions can be integrated in one processing module. The integrated module can be realized in the form of hardware or software functional module. It should be noted that the division of the modules in the embodiments of the present application is illustrative, and is only a logical functional division, and another division manner can be used in actual implementation. The following will be described taking the example of dividing each functional module according to each function.

[0194] FIG. 11 is a schematic block diagram of the communication apparatus 10 provided by the embodiments of the present application. The apparatus 10 includes a transceiver module 11 and a processing module 12. The transceiver module 11 can realize corresponding communication functions, and the processing module 12 is used for data processing, or in other words, the transceiver module 11 is used for performing operations related to receiving and sending, and the processing module 12 is used for performing other operations except receiving and sending. The transceiver module 11 can also be referred to as a communication interface or a communication unit.

[0195] Optionally, the apparatus 10 can further include a storage module 13, which can be used to store instructions and / or data, and the processing module 12 can read the instructions and / or data in the storage module to enable the apparatus to implement the actions of the device in each of the foregoing method embodiments.

[0196] In one design, the apparatus 10 can correspond to the first network device or the second network device in the method embodiments described above, or be a constituent component (such as a chip) of the first network device or the second network device apparatus.

[0197] The apparatus 10 can implement the steps or procedures performed by the first network device or the second network device in FIG. 7, where the transceiver module 11 can be configured to perform the transceiver-related operations of the first network device or the second network device in FIG. 7, and the processing module 12 can be configured to perform the processing-related operations of the first network device in FIG. 7.

[0198] It should also be understood that the apparatus 10 herein is embodied in the form of a functional module. The term "module" herein can refer to an application specific integrated circuit (ASIC), an electronic circuit, a processor (shared, dedicated or group) and memory that execute one or more software or firmware programs, a combinational logic circuit, and / or other suitable components that provide the described functionality. In one optional example, those skilled in the art can understand that the apparatus 10 can be embodied as the first communication device in the above-described embodiments, and can be configured to perform the procedures and / or steps corresponding to the first communication device in the above-described method embodiments; or the apparatus 10 can be embodied as the second communication device in the above-described embodiments, and can be configured to perform the procedures and / or steps corresponding to the second communication device in the above-described method embodiments. For the sake of brevity, details are not repeated here.

[0199] The apparatus 10 of each of the above-described schemes has the function of implementing the corresponding steps performed by the device (e.g., the first communication device) in the above-described methods. The function can be implemented by hardware or by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the above-described functions; for example, the transceiver module can be replaced by a transceiver (e.g., the sending unit in the transceiver module can be replaced by a transmitter, and the receiving unit in the transceiver module can be replaced by a receiver), and other units such as the processing module can be replaced by a processor, which respectively perform the transceiver operations and related processing operations in each of the method embodiments.

[0200] In addition, the transceiver module 11 described above can also be a transceiver circuit (e.g., which can include a receiving circuit and a sending circuit), and the processing module can be a processing circuit.

[0201] FIG. 12 is a schematic diagram of another communication apparatus 20 provided by the embodiments of the present application. The apparatus 20 includes a processor 21 configured to execute computer programs or instructions stored in a memory 22, or read data / signaling stored in the memory 22, to perform the methods in the above-described method embodiments. Optionally, the processor 21 is one or more.

[0202] Optionally, as shown in FIG. 12, the apparatus 20 further includes a memory 22, which is configured to store computer programs or instructions and / or data. The memory 22 can be integrated with the processor 21, or can also be separately arranged. Optionally, the memory 22 is one or more.

[0203] Optionally, as shown in FIG. 12, the apparatus 20 further includes a transceiver 23, which is configured to receive and / or send signals. For example, the processor 21 is configured to control the transceiver 23 to receive and / or send signals.

[0204] As an option, the apparatus 20 is configured to implement operations performed by an access network device or a master node MN or a secondary node SN in the various method embodiments.

[0205] It should be understood that the processor mentioned in the embodiments of the present application can be a central processing unit (CPU), and can also be other general-purpose processors, digital signal processors (DSP), application specific integrated circuits (ASIC), field programmable gate arrays (FPGA) or other programmable logic devices, discrete gates or transistor logic components, discrete hardware components, etc. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor.

[0206] It should also be understood that the memory mentioned in the embodiments of the present application can be a volatile memory and / or a non-volatile memory. Among them, the non-volatile memory can be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically EPROM (EEPROM) or a flash memory. The volatile memory can be a random access memory (RAM). For example, the RAM can be used as an external cache. As an example but not limitation, the RAM includes the following various forms: static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), synchlink DRAM (SLDRAM) and direct rambus RAM (DR RAM).

[0207] It should be noted that when the processor is a general processor, a DSP, an ASIC, a FPGA or other programmable logic device, a discrete gate or transistor logic device, a discrete hardware component, the memory (storage module) can be integrated in the processor.

[0208] It should also be noted that the memory described herein is intended to include, but not limited to, these and any other suitable types of memory.

[0209] FIG. 13 is a schematic diagram of a chip system 30 provided by an embodiment of the present application. The chip system 30 (or also can be referred to as a processing system) includes a logic circuit 31 and an input / output interface 32.

[0210] Among them, the logic circuit 31 can be a processing circuit in the chip system 30. The logic circuit 31 can be coupled to a storage unit, call instructions in the storage unit, so that the chip system 30 can realize the method and function of each embodiment of the present application. The input / output interface 32 can be an input / output circuit in the chip system 30, which outputs the information processed by the chip system 30 or inputs the data or signaling information to be processed into the chip system 30 for processing.

[0211] As a solution, the chip system 30 is configured to implement operations performed by the access network device or the master node MN or the secondary node SN in the above various method embodiments.

[0212] For example, the logic circuit 31 is configured to implement processing-related operations performed by the access network device or the master node MN or the secondary node SN in the above method embodiments; and the input / output interface 32 is configured to implement sending and / or receiving-related operations performed by the terminal device in the above method embodiments.

[0213] Embodiments of the present application also provide a computer readable storage medium having stored thereon computer instructions for implementing the method performed by the device in the above various method embodiments.

[0214] For example, the computer program, when executed by a computer, enables the computer to implement the method performed by the access network device or the master node MN or the secondary node SN in the above various method embodiments.

[0215] Embodiments of the present application also provide a computer program product comprising instructions, which, when executed by a computer, implement the method performed by the access network device or the master node MN or the secondary node SN in the above various method embodiments.

[0216] Embodiments of the present application also provide a communication system comprising the aforementioned master node MN and secondary node SN.

[0217] The explanations and beneficial effects of the related contents in any of the above-provided devices can refer to the corresponding method embodiments provided above, and will not be repeated here.

[0218] Those skilled in the art can understand that the units and algorithm steps of the examples described in combination with the embodiments disclosed herein can be realized in electronic hardware or a combination of computer software and electronic hardware. Whether the functions are realized in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0219] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the above-described system, device and unit can refer to the corresponding processes in the foregoing method embodiments, which will not be repeated here.

[0220] In several embodiments provided in the present application, it should be understood that the disclosed system, device and method can be implemented in other manners. For example, the described device embodiments are merely schematic. The division of the units is merely logical function division. There can be other division manners in actual implementation. For example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the displayed or discussed mutual couplings or direct couplings or communication connections can be indirect couplings or communication connections through some interfaces, devices or units, and can be in electrical, mechanical or other forms.

[0221] The units described as separate components can or can not be physically separate, and the components shown as units can or can not be physical units, i.e., can be located in one place, or can be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the embodiment.

[0222] In addition, each functional unit in the various embodiments of the present application can be integrated into a processing unit, or each unit can be a physically separate unit, or two or more units can be integrated into one unit.

[0223] If the functions are realized in the form of software function units and sold or used as independent products, they can be stored in a computer readable storage medium. Based on this understanding, the technical solutions of the present application can be embodied in the form of a software product, and the computer software product is stored in a storage medium, and includes a number of instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present application. The aforementioned storage medium includes: a U disk, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, and various media that can store program codes.

[0224] The above description is merely a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art can easily think of changes or replacements within the technical scope disclosed in the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A method for communication in a dual connectivity (DC) scenario, the method comprising: The method is applied to a first network device, configuring, for a user equipment (UE), discarding based on protocol data unit set importance (PSI); sending, to a second network device, first information used to inform the second network device that the first network device has configured discarding based on PSI for the UE.

2. The method of claim 1, wherein, The configuring, for the UE, discarding based on PSI comprises: sending, to the UE, configuration information used to configure the UE with discarding based on uplink PSI.

3. The method according to claim 1 or 2, characterized in that, The configuring, for the UE, discarding based on PSI comprises: determining to configure the UE with discarding based on downlink PSI.

4. The method according to any one of claims 1 to 3, characterized in that, The first network device is a master node (MN), and the first information is carried in an S-NODE ADDITION / MODIFICATION REQUEST message.

5. The method according to any one of claims 1 to 3, characterized in that, The first network device is a secondary node (SN), and the first information is carried in an S-NODE ADDITION / MODIFICATION REQUEST ACKNOWLEDGE or S-NODE MODIFICATION REQUIRED message. 6.A method for communication in a dual connectivity (DC) scenario, comprising: The method is applied to a first network device, receiving, from a second network device, assistance information used to feed back a radio resource congestion state of the second network device, the assistance information comprising one or more of: a suggestion of activating / deactivating discarding based on protocol data unit set importance (PSI); a congestion state of the network device; a congestion level of the network device; a maximum air interface rate that the network device can support; and / or based on the assistance information, performing one or more of: indicating a user equipment (UE) to activate / deactivate discarding based on protocol data unit set importance (PSI); activating / deactivating discarding based on downlink PSI; adjusting a split ratio of a split bearer; feeding back congestion information to a core network; and adding an explicit congestion notification (ECN) to a data packet.

7. The method of claim 6, wherein, The method further comprises: determining, by the first network device, a congestion state condition of the first network device and the second network device, the congestion state condition being one of: a first condition: the first network device is congested and the second network device is congested; a second condition: the first network device is congested or the second network device is congested; a third condition: the first network device is not congested or the second network device is not congested; a fourth condition: the first network device is not congested and the second network device is not congested; based on the first condition or the second condition, indicating the UE to activate discarding based on PSI. based on the third condition or the fourth condition, activating / deactivating discarding based on downlink PSI. According to the third condition or the fourth condition, the UE is instructed to deactivate the dropping based on protocol data unit set importance (PSI).

8. The method of claim 6, wherein, the assistance information is carried in an Xn interface message or in a protocol data unit (PDU) header.

9. The method of claim 6 or 7, wherein, a CU of the first network device receives the assistance information sent by a DU of the first network device, and the assistance information can be carried in an F1 interface message.

10. The method of any of claims 1 to 4, wherein, the first network device is a master node (MN) in a dual connectivity (DC) scenario, and the second network device is a secondary node (SN) in the DC scenario; or the first network device is the SN in the DC scenario, and the second network device is the MN in the DC scenario. 11.A communication method applied to a dual connectivity (DC) scenario, the method comprising: applying to a second network device, sending, to a first network device, assistance information used for feeding back a radio resource congestion state of the second network device, and the assistance information can include one or more of the following: activation / deactivation of a suggestion of dropping based on PSI; a congestion state of the network device; a congestion level of the network device; an air interface rate that can be supported by the network device, and the like.

12. The method of claim 11, wherein, a CU of the second network device receives the assistance information sent by a DU of the second network device, and the assistance information can be carried in an F1 interface message.

13. The method of claim 11 or 12, wherein, the first network device is a master node (MN) in a dual connectivity (DC) scenario, and the second network device is a secondary node (SN) in the DC scenario; or the first network device is the SN in the DC scenario, and the second network device is the MN in the DC scenario.

14. A data transmission method applied to dual connectivity (DC), comprising: a first network device receiving, from a core network, a PDU data packet carrying data burst end indication information (End of data burst), the data burst end indication information being used to indicate that data transmission of the data burst is completed; and sending, to a second network device, the data burst end indication information (End of data burst).

15. The method of claim 14, wherein, the sending, to the second network device, of the data burst end indication information (End of data burst) can be performed in one or more of the following ways: forwarding the PDU data packet received from the core network, the PDU data packet carrying the data burst end indication information (End of data burst); adding the end of data burst indication information (End of data burst) in a PDU packet forwarded to the second network device; sending an empty PDU packet carrying the end of data burst indication information (End of data burst) to the second network device.

16. The method of claim 14 or 15, wherein the CU of the first network device sends the end of data burst indication information (End of data burst) to the DU of the first network device.

17. A communication apparatus, comprising: a processor coupled with a memory, the memory being configured to store computer programs or instructions, and the processor being configured to execute the computer programs or instructions in the memory, so that the apparatus performs the method of any one of claims 1 to 16.

18. A computer readable storage medium, comprising: computer programs or instructions stored thereon, which, when executed on a computer, cause the computer to perform the method of any one of claims 1 to 16.

19. A chip system, characterized by including: a processor configured to invoke and run computer programs from a memory, so that a communication device installed with the chip system performs the method of any one of claims 1 to 16.

20. A computer program product, comprising: which, when executed on a computer, cause the computer to perform the method of any one of claims 1 to 16.

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