Data transmission methods and apparatuses, device, and storage medium

Abstract

Data transmission methods and apparatuses, a device, and a storage medium, relating to the technical field of communications. A method is executed by a first device, and the method comprises: controlling a first protocol stack to transmit or retransmit to a first network device the first type of data packets, an upper-layer protocol stack of the first protocol stack being an RRC layer or an SDAP layer or an IP layer, a lower-layer protocol stack of the first protocol stack being an MAC layer, and the first network device being a network device of a target cell where a terminal device camps after performing a cell handover (310). Thus, a new protocol stack structure is provided, and the terminal device uses the first protocol stack to transmit or retransmit data packets, the lower-layer protocol stack of the first protocol stack being an MAC layer, and the upper-layer protocol stack of the first protocol stack being an SDAP layer or an RRC layer or an IP layer. Only one data layer in the first protocol stack is used to process data to be transmitted, thus function repetition among multiple protocol stacks is prevented, thereby helping to reduce the complexity of data processing for terminal devices.

Description

Data transmission methods, apparatus, equipment and storage media Technical Field

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

[0002] In NR (New Radio) systems, the L2 layer of the protocol stack is divided into four sub-layers, including two data layers: RLC (Radio Link Control) and PDCP (Packet Data Convergence Protocol). The RLC and PDCP layers use different message headers, but functionally, aside from the security functions handled by the PDCP layer, there is some overlap in data transmission between them. Terminal devices need to perform redundant data processing, resulting in a high complexity in data processing.

[0003] Summary of the Invention

[0004] This application provides a data transmission method, apparatus, device, and storage medium. The technical solutions provided by this application are as follows:

[0005] According to one aspect of the embodiments of this application, a data transmission method is provided, the method being executed by a terminal device, the method comprising:

[0006] The system controls the first protocol stack to transmit or retransmit the first type of data packets to the first network device. The upper layer of the first protocol stack is the RRC (Radio Resource Control) layer, the SDAP (Service Data Adaptation Protocol) layer, or the IP (Internet Protocol) layer. The lower layer of the first protocol stack is the MAC (Media Access Control) layer. The first network device is the network device where the target cell where the terminal device camps after cell handover is located.

[0007] According to one aspect of the embodiments of this application, a data transmission method is provided, the method being executed by a first network device, the method comprising:

[0008] The first type of data packet transmitted or retransmitted by the first protocol stack of the receiving terminal device, wherein the upper layer protocol stack of the first protocol stack is the RRC layer, SDAP layer, or IP layer, the lower layer protocol stack of the first protocol stack is the MAC layer, and the first network device is the network device where the target cell where the terminal device camps after cell handover is located.

[0009] According to one aspect of the embodiments of this application, a data transmission apparatus is provided, the apparatus comprising:

[0010] The processing module is used to control the transmission or retransmission of the first type of data packets by the first protocol stack. The upper layer protocol stack of the first protocol stack is the RRC layer, the SDAP layer, or the IP layer, and the lower layer protocol stack of the first protocol stack is the MAC layer. The first network device is the network device where the target cell where the terminal device camps after cell handover is performed.

[0011] According to one aspect of the embodiments of this application, a data transmission apparatus is provided, the apparatus comprising:

[0012] The receiving module is used to receive the first type of data packets transmitted or retransmitted by the first protocol stack of the terminal device. The upper layer protocol stack of the first protocol stack is the RRC layer, SDAP layer, or IP layer, and the lower layer protocol stack of the first protocol stack is the MAC layer. The first network device is the network device where the target cell where the terminal device camps after cell handover is located.

[0013] According to one aspect of the embodiments of this application, a communication device is provided, the communication device including a processor and a memory, the memory storing a computer program, and the processor executing the computer program to implement the above-described data transmission method. The communication device is a terminal device, or the communication device is a network device.

[0014] According to one aspect of the embodiments of this application, a computer-readable storage medium is provided, the storage medium storing a computer program for execution by a processor to implement the above-described data transmission method.

[0015] According to one aspect of the embodiments of this application, a chip is provided, the chip including programmable logic circuits and / or program instructions, which, when the chip is running, are used to implement the above-described data transmission method.

[0016] According to one aspect of the embodiments of this application, a computer program product is provided, the computer program product including computer instructions stored in a computer-readable storage medium, and a processor reading from the computer-readable storage medium and executing the computer instructions to implement the above-described data transmission method.

[0017] The technical solutions provided in this application embodiment may have the following beneficial effects:

[0018] A novel protocol stack structure is presented, in which the terminal device uses a first protocol stack to transmit or retransmit data packets. The lower layer of the first protocol stack is the MAC layer, and the upper layer is either the SDAP layer, RRC layer, or IP layer. By using only one data layer (the first protocol stack) to process transmitted data, functional duplication between multiple protocol stacks is avoided, which helps reduce the complexity of data processing in the terminal device. Attached Figure Description

[0019] Figure 1 is a schematic diagram of a network architecture provided in one embodiment of this application;

[0020] Figure 2 is a schematic diagram of the protocol stack of a terminal device provided in an embodiment of this application;

[0021] Figure 3 is a flowchart of a data transmission method provided in an embodiment of this application;

[0022] Figure 4 is a flowchart of a data transmission method provided in another embodiment of this application;

[0023] Figure 5 is a flowchart of a data transmission method provided in another embodiment of this application;

[0024] Figure 6 is a block diagram of a data transmission apparatus provided in an embodiment of this application;

[0025] Figure 7 is a block diagram of a data transmission apparatus provided in another embodiment of this application;

[0026] Figure 8 is a schematic diagram of the structure of a communication device provided in an embodiment of this application. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0028] The network architecture and business scenarios described in the embodiments of this application are for the purpose of more clearly illustrating the technical solutions of the embodiments of this application, and do not constitute a limitation on the technical solutions provided in the embodiments of this application. As those skilled in the art will know, with the evolution of network architecture and the emergence of new business scenarios, the technical solutions provided in the embodiments of this application are also applicable to similar technical problems.

[0029] Please refer to Figure 1, which shows a schematic diagram of a network architecture 100 provided in one embodiment of this application. The network architecture 100 may include: a terminal device 10, an access network device 20, and a core network element 30.

[0030] Terminal device 10 can refer to UE (User Equipment), STA (Station), access terminal, user unit, user station, mobile station, mobile station, remote station, remote terminal, mobile device, wireless communication device, user agent, or user equipment. In some embodiments, terminal device 10 can also be a cellular phone, cordless phone, SIP (Session Initiation Protocol) phone, WLL (Wireless Local Loop) station, PDA (Personal Digital Assistant), handheld device with wireless communication capabilities, computing device or other processing device connected to a wireless modem, vehicle-mounted device, wearable device, terminal device in 5GS (5th Generation System), or terminal device in the future evolved PLMN (Public Land Mobile Network), etc., and this application embodiment is not limited to these. For ease of description, the devices mentioned above are collectively referred to as terminal devices. The number of terminal devices 10 is usually multiple, and one or more terminal devices 10 can be distributed within the cell managed by each access network device 20. Terminal equipment can also be simply referred to as terminal or UE, the meaning of which can be understood by those skilled in the art.

[0031] Access network device 20 is a device deployed in an access network to provide wireless communication functionality to terminal device 10. Access network device 20 may include various forms of macro base stations, micro base stations, relay stations, APs (Access Points), etc. In systems employing different wireless access technologies, the name of the device with access network device functionality may differ; for example, in a 5G NR (New Radio) system, it is called gNodeB or gNB (Next Generation Node B). As communication technologies evolve, the name "access network device" may change. For ease of description, in this embodiment, the aforementioned devices providing wireless communication functionality to terminal device 10 are collectively referred to as access network devices. In some embodiments, a communication relationship can be established between terminal device 10 and core network element 30 through access network device 20. For example, in an LTE (Long Term Evolution) system, access network device 20 can be one or more eNodeBs within an EUTRAN (Evolved Universal Terrestrial Radio Access Network); in a 5G NR system, access network device 20 can be one or more gNBs within a RAN (Radio Access Network). In the embodiments of this application, unless otherwise specified, "network device" refers to access network device 20, such as a base station.

[0032] Core network element 30 is a network element deployed in the core network. Its main functions are to provide user connectivity, manage users, and bear services, serving as an interface to external networks. For example, core network elements in a 5G NR system may include AMF (Access and Mobility Management Function) entities, UPF (User Plane Function) entities, and SMF (Session Management Function) entities.

[0033] In some embodiments, the access network device 20 and the core network element 30 communicate with each other via some air interface technology, such as the NG interface in a 5G NR system. The access network device 20 and the terminal device 10 communicate with each other via some air interface technology, such as the Uu interface.

[0034] The "5G NR system" in this application embodiment can also be referred to as a 5G system or an NR system, but those skilled in the art will understand its meaning. The technical solutions described in this application embodiment can be applied to LTE systems, 5G NR systems, and subsequent evolution systems of 5G NR systems (such as B5G (Beyound 5G) systems, 6G systems (6th Generation System), and other communication systems such as NB-IoT (Narrow Band Internet of Things) systems. This application does not limit these applications.

[0035] In this embodiment, the network device can provide services to a cell. The terminal device communicates with the network device through the transmission resources (e.g., frequency domain resources, or spectrum resources) on the carrier used by the cell. The cell can be the cell corresponding to the network device (e.g., a base station). The cell can belong to a macro base station or to a base station corresponding to a small cell. The small cell can include: metro cell, micro cell, pico cell, femto cell, etc. These small cells have the characteristics of small coverage area and low transmission power, and are suitable for providing high-speed data transmission services.

[0036] Before introducing the technical solution of this application, some related technical knowledge involved in this application will be introduced and explained. The following related technologies are optional solutions and can be arbitrarily combined with the technical solutions of the embodiments of this application, all of which fall within the protection scope of the embodiments of this application. The embodiments of this application include at least some of the following contents.

[0037] Currently, with people's pursuit of speed, latency, high-speed mobility, and energy efficiency, as well as the diversity and complexity of services in future life, the 3GPP international standards organization has begun to develop 5G. The main application scenarios of 5G are: Enhanced Mobile Broadband (eMBB), Ultra Reliable Low Latency Communications (URLLC), and Massive Machine Type Communications (mMTC).

[0038] eMBB still aims to provide users with multimedia content, services, and data, and its demand is growing rapidly. On the other hand, because eMBB may be deployed in different scenarios, such as indoors, urban areas, and rural areas, its capabilities and needs vary considerably. Therefore, generalizations cannot be made; a detailed analysis based on the specific deployment scenario is necessary. Typical applications of URLLC include industrial automation, power automation, remote medical operations (surgery), and traffic safety assurance. Typical characteristics of mMTC include high connection density, small data volume, latency-insensitive services, low module cost, and long module lifespan.

[0039] NR can also be deployed independently. In 5G network environments, to reduce air interface signaling and quickly restore wireless connections and data services, a new RRC state, namely the RRC_INACTIVE state, is defined. This state is different from the RRC_IDLE and RRC_ACTIVE states.

[0040] RRC_IDLE: Mobility is based on UE-based cell selection and reselection. Paging is initiated by the CN (Core Network), and the paging area is configured by the CN. There is no UE AS (Access Stratum) context on the base station side. No RRC connection exists.

[0041] RRC_CONNECTED: An RRC connection exists, and the base station and UE share a UE AS context. The network side knows the UE's location at the cell level. Mobility is network-controlled. Unicast data can be transmitted between the UE and the base station.

[0042] RRC_INACTIVE: Mobility is based on UE cell selection reselection, there is a connection between CN and NR, the UE AS context exists on a certain base station, paging is triggered by RAN (Radio Access Network), the RAN-based paging area is managed by RAN, and the network side knows the UE's location at the RAN-based paging area level.

[0043] 1. NR User Plane Protocol Stack

[0044] As shown in Figure 2, the L2 layer of the NR protocol stack is divided into four sub-layers: Media Access Control (MAC), Radio Link Control (RLC), Packet Data Convergence Protocol (PDCP), and Service Data Adaptation Protocol (SDAP).

[0045] The services and functions of the PDCP layer include:

[0046] ●Serial number;

[0047] ● Header compression and decompression (only ROHC (RObust Header Compression, IP header compression) is supported);

[0048] ●User data transmission;

[0049] ● Reordering and duplicate detection;

[0050] ●Passing in sequence;

[0051] ●PDCP PDU (Protocol Data Unit) routing (if it is split bearers);

[0052] ●Retransmission of PDCP SDU (Service Data Unit);

[0053] ● Encryption, decryption, and integrity protection;

[0054] ● PDCP SDU discarded;

[0055] ●PDCP reconstruction and data recovery (RLC AM (Acknowledged) mode);

[0056] ●PDCP status report (for RLC AM mode);

[0057] ● PDCP PDU is repeatedly detected and the RLC is instructed to discard it.

[0058] The RLC layer supports three transmission modes: Transparent Transmission (TM), Un-Acknowledged (UM) mode, and AM mode. The main difference between these modes is the presence or absence of Automatic Repeat Request (ARQ) functionality. RLC divides radio bearers in NR into two groups: Data Radio Bearers (DRBs) for user plane data and Signalling Radio Bearers (SRBs) for control plane data. RLC-TM mode is used to transmit SRB0, paging, and System Information (SI) information, while RLC-AM mode is used for other SRBs. For DRB transmission, either RLC-UM or RLC-AM can be used. Some services and functions of the RLC layer depend on the transmission mode. These services include:

[0059] ●Transmission of upper-layer PDUs;

[0060] ●Sequence numbers independent of PDCP (RLC-UM and RLC-AM);

[0061] ● Error correction is performed using the ARQ function (AM mode);

[0062] ● RLC SDUs partitioning (in RLC-AM and RLC-UM modes) and repartitioning (in RLC-AM mode);

[0063] ● Reassembly of SDU (in RLC-AM and RLC-UM modes);

[0064] ● Repeat detection (in RLC-AM mode);

[0065] ● RLC SDU discard (in RLC-AM and RLC-UM modes);

[0066] ●RLC reconstruction;

[0067] ●And protocol error detection (in RLC AM mode).

[0068] The ARQ function in the RLC layer performs ARQ retransmission of RLC SDU or SDU segments based on the RLC status report. It also sends requests for RLC status reports when needed and triggers an RLC status report upon detecting a lost RLC SDU or SDU segment. If necessary, the RLC protocol performs PDCP PDU segmentation and adds an RLC header containing a sequence number for handling retransmissions. Unlike LTE, NR RLC does not provide data order delivery to higher layers due to the additional delay caused by the reordering mechanism. The PDCP layer can provide order delivery if necessary.

[0069] In related technologies, two different data layers, RLC and PDCP, use different message headers. However, from a functional perspective, apart from the security functions currently undertaken by PDCP, there is some overlap in data transmission functions with those of RLC. Considering that next-generation networks need to handle larger amounts of data, removing one data layer and using a unified data layer to process data, thus avoiding redundant functions, would help reduce the processing complexity of terminals.

[0070] When a UE performs a handover, the following steps are required in a traditional network:

[0071] - The RLC layer is cleared;

[0072] - The PDCP layer is used for reconstruction or data recovery.

[0073] However, if a unified data layer is used for processing, how to handle the operations during the switching process is a problem that must be solved.

[0074] Please refer to Figure 3, which shows a flowchart of a data transmission method provided in an embodiment of this application. The method is executed by a terminal device and includes the following step 310.

[0075] Step 310: The terminal device controls the first protocol stack to transmit or retransmit the first type of data packet to the first network device. The upper layer protocol stack of the first protocol stack is the RRC layer, SDAP layer, or IP layer, and the lower layer protocol stack of the first protocol stack is the MAC layer. The first network device is the network device where the target cell where the terminal device camps after cell handover is located.

[0076] Accordingly, the network device receives the first type of data packet sent by the first protocol stack of the terminal device for transmission or retransmission.

[0077] In some embodiments, after receiving a handover command, the terminal device executes step 310 as described above. In some embodiments, after receiving a handover command, the terminal device begins the cell handover process. In some embodiments, the handover command instructs the terminal device to hand over from the source cell to the target cell. In some embodiments, the target cell to which the terminal device hands over may be indicated by the network device or may be determined by the terminal device itself based on measurement results. In some embodiments, the source cell and the target cell may be located under the same network device or under different network devices; this application does not limit this.

[0078] In some embodiments, the terminal device actively initiates the cell handover process.

[0079] In some embodiments, the terminal device performs step 310 as described above during cell handover.

[0080] In some embodiments, the terminal device performs step 310 as described above after cell handover.

[0081] In some embodiments, the first protocol stack combines the functions of both the PDCP layer and the RLC layer. In some embodiments, the services and functions of the first protocol layer include at least one of the following:

[0082] ●Serial number;

[0083] ●Header compression and decompression;

[0084] ●User data transmission;

[0085] ● Reordering and duplicate detection;

[0086] ●Passing in sequence;

[0087] ● PDU routing (if it is split bearers);

[0088] ● SDU retransmission;

[0089] ● Encryption, decryption, and integrity protection;

[0090] ●SDU discarded;

[0091] ● Reconstruction and data recovery (RLC AM mode);

[0092] ● Status report (for RLC AM mode);

[0093] ● Duplicate detection and discarding of PDUs.

[0094] In some embodiments, the first protocol layer integrates the services and functions of the PDCP layer and the RLC layer. In some embodiments, the first protocol layer may also be referred to as the convergence layer.

[0095] In some embodiments, the terminal device retransmits the first type of data packet by default.

[0096] In some embodiments, the first type of data packet includes at least one of the following:

[0097] Data packets that were not acknowledged as received by the first network device;

[0098] Data packets that are not acknowledged for receipt by the second network device, which is the network device where the source cell is located before the terminal device performs cell handover;

[0099] Data packets following the first data packet that was not acknowledged by the first network device;

[0100] Data packets following the first data packet that was not acknowledged by the second network device;

[0101] Data packets that are not delivered to the underlying protocol stack, which refers to the protocol stack at the bottom of the first protocol stack.

[0102] In some embodiments, the first network device is the network device where the target cell where the terminal device camps after cell handover is located. In some embodiments, the first network device and the second network device may be the same network device or different network devices, and this application does not limit this.

[0103] In some embodiments, the first type of data packets includes data packets that have not been acknowledged as received by the first network device. For example, if the first network device acknowledges the receipt of data packets 1, 3, and 4, then the terminal device will acknowledge data packets 2 and 5 as first type data packets.

[0104] In some embodiments, the first type of data packets includes data packets following the first data packet that was not acknowledged as received by the first network device. For example, if the first network device acknowledges the receipt of data packets 1, 3, and 4, then the terminal device will acknowledge data packets 2 to 5 as first type of data packets.

[0105] In some embodiments, the first type of data packets includes data packets that have not been acknowledged as received by the second network device. For example, if the second network device acknowledges the receipt of data packets 1, 3, and 4, then the terminal device will acknowledge data packets 2 and 5 as first type data packets.

[0106] In some embodiments, the first type of data packets includes data packets following the first data packet that was not acknowledged as received by the second network device. For example, if the second network device acknowledges the receipt of data packets 1, 3, and 4, then the terminal device will acknowledge data packets 2 to 5 as first type of data packets.

[0107] In some embodiments, the first type of data packets includes data packets that have not been acknowledged as received by the first network device and have not been acknowledged as received by the second network device. For example, if the first network device acknowledges the receipt of data packet 1 and the second network device acknowledges the receipt of data packet 3, then the terminal device will acknowledge data packets 2, 4, and 5 as the first type of data packets.

[0108] In some embodiments, the first type of data packets includes data packets following the first data packet that was not acknowledged as received by the first network device and was not acknowledged as received by the second network device. For example, if the first network device acknowledges the receipt of data packets 1 and 3, and the second network device acknowledges the receipt of data packets 1, 3, and 4, then the terminal device will acknowledge data packets 2 to 5 as first type of data packets.

[0109] In some embodiments, the first protocol layer may also buffer data packets that have not been delivered to the underlying protocol stack, and the terminal device controls the first protocol layer to transmit these data packets. In some embodiments, the underlying protocol stack refers to the protocol stack beneath the first protocol stack. In some embodiments, the underlying protocol stack is a MAC layer or a PHY (Port Physical Layer) layer.

[0110] In some embodiments, the transmission or retransmission of data packets not delivered to the underlying protocol stack is performed under UM. In some embodiments, under UM, for the sake of data packet transmission efficiency, the packet header is not processed. Therefore, after cell handover, data packets under UM can be transmitted directly without considering whether the packet header compression algorithm has changed or whether the key has changed.

[0111] The technical solution provided in this application presents a novel protocol stack structure. The terminal device uses a first protocol stack to transmit or retransmit data packets. The lower protocol stack of the first protocol stack is the MAC layer, and the upper protocol stack is either the SDAP layer, RRC layer, or IP layer. By using only one data layer (the first protocol stack) to process transmitted data, functional duplication between multiple protocol stacks is avoided, which helps reduce the complexity of data processing in the terminal device.

[0112] In some embodiments, the data packets transmitted or retransmitted by the first protocol stack may also be determined by the terminal device based on indication information sent by the network device. In some embodiments, the data packets transmitted or retransmitted by the first protocol stack are determined based on indication information sent by the network device. In some embodiments, the data packets transmitted or retransmitted by the first protocol stack are indicated by the network device.

[0113] In some embodiments, the second type of data packet includes at least one of the following:

[0114] The data packet that is acknowledged as received by the first network device;

[0115] The data packet acknowledged and received by the second network device, which is the network device where the source cell is located before the terminal device performs cell handover;

[0116] Data packets following the first data packet that was not acknowledged by the first network device;

[0117] The data packet following the first data packet that was not acknowledged by the second network device.

[0118] 1. The data packets transmitted or retransmitted by the first protocol stack are determined based on the indication information sent by the network device. In some embodiments, the method further includes at least one of the following steps 320 to 330.

[0119] Step 320: The terminal device receives first information, which is used to indicate the data packet reception status.

[0120] Accordingly, the network device sends the first message.

[0121] Step 330: Based on the first information, the terminal device determines the second type of data packet that needs to be retransmitted.

[0122] In some embodiments, the first information is transmitted during cell handover.

[0123] In some embodiments, the first information is transmitted during data transmission.

[0124] In some embodiments, the first information is received by the terminal device before cell handover.

[0125] In some embodiments, the first information is received by the terminal device after cell handover.

[0126] In some embodiments, the first information is sent by the second network device.

[0127] In some embodiments, the first information is sent by a first network device.

[0128] In some embodiments, the terminal device may receive first information sent by a first network device or a second network device.

[0129] In some embodiments, the first information is SR (Status Report) information.

[0130] In some embodiments, the terminal device determines a second type of data packet that needs to be retransmitted based on first information from a first network device and / or first information from a second network device.

[0131] In some embodiments, the first information is used to indicate data packets that have been acknowledged as received by the network device.

[0132] In some embodiments, the first information is used to indicate data packets that have not been acknowledged by the network device.

[0133] In some embodiments, the terminal device, based on the first information, identifies data packets that have not been acknowledged by the network device as a second type of data packet that needs to be retransmitted.

[0134] For example, if the first information from the second network device indicates that data packets 1 and 3 have not been received correctly, the terminal device will identify data packets 1 and 3 as second-type data packets.

[0135] For example, if the first information from the first network device indicates that data packets 1 and 3 have not been received correctly, the terminal device will identify data packets 1 and 3 as second-type data packets.

[0136] For example, if the first information from the second network device indicates that data packets 1 and 3 have not been received correctly, and the first information indicating that data packet 2 has been received correctly by the first network device is not received, then the terminal device will identify data packets 1 to 3 as second type data packets.

[0137] For example, if the first information from the second network device indicates that data packets 1 and 3 have not been received correctly, and the terminal device receives the first information indicating that data packet 2 has not been received correctly by the first network device, then the terminal device will identify data packets 1 to 3 as second type data packets.

[0138] 2. The data packets transmitted or retransmitted by the first protocol stack are indicated by the network device. In some embodiments, the method further includes the following step 340.

[0139] Step 340: The terminal device receives second information, which indicates that a second type of data packet needs to be retransmitted.

[0140] Accordingly, the network device sends a second message.

[0141] In some embodiments, the second information is sent by a second network device.

[0142] In some embodiments, the second information is sent by the first network device.

[0143] In some embodiments, the terminal device may receive second information sent by the first network device or the second network device.

[0144] In some embodiments, the second type of data packet indicated by the second information may be a data packet acknowledged as received by the network device, or a data packet not acknowledged as received by the network device.

[0145] In some embodiments, the terminal device may determine the second type of data packet based on the first information and the second information.

[0146] For example, if the first information from the second network device indicates that data packets 1 and 3 have not been received correctly, and the terminal device receives the second information indicating that data packet 2 needs to be retransmitted, then the terminal device will identify data packets 1 to 3 as second-type data packets.

[0147] For example, if the first information from the second network device indicates that data packets 1 and 3 have not been received correctly, and the terminal device receives the second information indicating that data packet 3 does not need to be retransmitted, then the terminal device will identify data packet 1 as a second type of data packet.

[0148] A method is provided for terminal devices to confirm data packets that need to be transmitted or retransmitted, so as to avoid data loss during cell handover and achieve lossless handover.

[0149] It should be noted that steps 320 to 340 can be performed before or after step 310. If steps 320 to 340 are performed after step 310, the method further includes step 350.

[0150] Step 350: The terminal device controls the first protocol stack to transmit or retransmit the second type of data packet.

[0151] In some embodiments, during cell handover, in addition to data transmission, the relevant configurations for data processing may also change.

[0152] In some embodiments, the first network device and the second network device may be the same network device or different network devices.

[0153] 1. The first network device and the second network device are different network devices.

[0154] For example, as shown in FIG4, the terminal device switches from the source cell to the target cell, where the source cell is located under the second network device and the target cell is located under the first network device.

[0155] In some embodiments, the method further includes at least one of steps 1 to 3 below.

[0156] Step 1: The terminal device receives the third information.

[0157] Accordingly, the network device sends third information.

[0158] In some embodiments, the third information may be sent by either a first network device or a second network device. For example, the third information may be sent by the first network device after cell handover. For example, the third information may be sent by the second network device before cell handover. For instance, the handover command may include the third information.

[0159] In some embodiments, the third information is used to indicate at least one of the following:

[0160] The terminal device performs a reconstruction operation of the first protocol stack;

[0161] The header compression algorithm of the first protocol stack is reset. The header compression algorithm is used to compress the header. The second network device is the network device where the source cell is located before the terminal device performs cell handover.

[0162] In some embodiments, the header compression algorithm includes at least one of the following: ROHC, EHC (Ethernet Header Compression).

[0163] In some embodiments, the packet header is compressed using the UDC (Uplink Data Compression) algorithm. In some embodiments, the UDC algorithm can be used not only to compress the packet header but also to compress the payload of the data packet.

[0164] In some embodiments, the reconstruction operation of the first protocol stack includes resetting the header compression algorithm of the first protocol stack.

[0165] The above method instructs the terminal device whether to reset the packet header compression algorithm, so that the packet header compression algorithm can resume normal operation after the terminal device performs cell handover.

[0166] Step 2: The terminal device receives the fourth information from the first network device.

[0167] Accordingly, the network device sends the fourth message.

[0168] In some embodiments, the fourth information may be sent by either the first network device or the second network device. For example, the fourth information may be sent by the first network device after a cell handover. For example, the fourth information may be sent by the second network device before a cell handover. For instance, the handover command may include the fourth information.

[0169] In some embodiments, the fourth information is used to indicate at least one of the following:

[0170] The terminal device performs a reconstruction operation of the first protocol stack;

[0171] Update the key. The key is used to protect data packets. The second network device is the network device where the source cell is located before the terminal device performs cell handover.

[0172] In some embodiments, the reconstruction operation of the first protocol stack includes updating the key.

[0173] In some embodiments, the third information and the fourth information may be the same piece of information or different pieces of information. For example, the third information and the fourth information may be the same piece of information, used to instruct the terminal device to perform a reconstruction operation of the first protocol stack.

[0174] In some embodiments, the fourth information is used to explicitly or implicitly indicate whether the terminal device needs to update the key.

[0175] For example, the fourth information explicitly indicates whether the terminal device needs to update the key. For instance, the fourth information uses one bit to indicate whether the key needs to be updated. For example, 0 indicates that the key needs to be updated, and 1 indicates that the key does not need to be updated.

[0176] For example, the fourth information implicitly indicates whether the terminal device needs to update its key. For instance, the content indicated by the fourth information is related to whether the terminal device needs to update its key. In some embodiments, this relationship may be predefined or preconfigured, or it may be indicated by the network device.

[0177] In some embodiments, the identification information of the packet in the target cell is associated with whether the key is updated.

[0178] In some embodiments, the fourth information is used to indicate the identification information of the group to which the target cell belongs, and the target cell is the cell that the terminal device connects to after handover.

[0179] In some embodiments, if the identification information of the target cell group indicated by the fourth information is the same as the identification information of the source cell group, the key is not updated.

[0180] In some embodiments, if the identification information of the target cell group indicated by the fourth information is different from the identification information of the source cell group, the key is updated.

[0181] The above method instructs the terminal device whether to reset the key, so that after cell handover, if the network device that established the communication connection with the terminal device changes, the terminal device can use the new key to protect the data packets at the security level.

[0182] Step 3: Clear the third type of data packets.

[0183] In some embodiments, the third type of data packet includes at least one of the following:

[0184] PDUs and / or PDU segments in the transmit buffer;

[0185] PDUs and / or PDU segments in the receive buffer;

[0186] Data packets that are in the receive buffer but have not been delivered to the upper protocol stack. The upper protocol stack refers to the protocol stack above the first protocol stack.

[0187] SDUs or PDUs stored in the SRB;

[0188] The second network device is the network device where the source cell is located before the terminal device performs cell handover.

[0189] In some embodiments, the terminal device clears data packets that have been processed using the old key.

[0190] In some embodiments, the first network device may be a network device with a first protocol stack or a network device without a first protocol stack.

[0191] In some embodiments, where the first network device has a first protocol stack, the third type of data packet may include PDU segments in a buffer and PDU segments in a receive buffer.

[0192] By using the above method, data packets that have been processed with the old key are cleared, ensuring that after cell handover, data packets that have been processed with the old key are no longer transmitted on the new path, thereby avoiding confusion with data packets processed with the new key.

[0193] 2. The first network device and the second network device are the same network device.

[0194] For example, as shown in Figure 5, the terminal device switches from the source cell to the target cell, and both the source cell and the target cell are located under the first network device.

[0195] In some embodiments, the method further includes at least one of steps 1 to 2 below.

[0196] Step 1: Retain the third type of data packet.

[0197] Step 2: Clear the SDU or PDU stored in the SRB.

[0198] In some embodiments, the third type of data packet includes at least one of the following:

[0199] PDUs and / or PDU segments in the transmit buffer;

[0200] PDUs and / or PDU segments in the receive buffer;

[0201] Data packets that are in the receive buffer but have not been delivered to the upper protocol stack. The upper protocol stack refers to the protocol stack above the first protocol stack.

[0202] The second network device is the network device where the source cell is located before the terminal device performs cell handover.

[0203] In some embodiments, if the communication connection between the terminal device and the network device remains unchanged after a cell handover, the key does not need to be updated.

[0204] In some embodiments, since key updates are not involved, old data packets and data packet segments do not need to be rebuilt and can continue to be transmitted, so the terminal device can retain the third type of data packets.

[0205] In some embodiments, the first network device may be a network device with a first protocol stack or a network device without a first protocol stack.

[0206] In some embodiments, where the first network device has a first protocol stack, the third type of data packet may include PDU segments in a buffer and PDU segments in a receive buffer.

[0207] By using the above method, since key updates are not involved, data packets that have been processed with the old key can still be transmitted on the new path. Therefore, the third type of data packets can be retained, reducing the complexity of data processing for terminal devices.

[0208] In some embodiments, the first network device may be a network device with a first protocol stack or a network device without a first protocol stack. Exemplary embodiments are described herein.

[0209] In some embodiments, the first information includes the reception status of data segments.

[0210] In some embodiments, where the first network device has a first protocol stack, the first information includes the reception status of data segments.

[0211] In some embodiments, if the first network device does not have a first protocol stack, the first information does not include the reception status of data segments.

[0212] In some embodiments, data segments can be transmitted between the terminal device and the network device.

[0213] In some embodiments, when the first network device has a first protocol stack, the terminal device and the network device can transmit data segments.

[0214] In some embodiments, if the first network device does not have a first protocol stack, data segments cannot be transmitted between the terminal device and the network device.

[0215] In some embodiments, the method further includes at least one of steps 1 to 2 below.

[0216] In some embodiments, regardless of whether the first network device and the second network device are the same network device, the following steps 1 to 2 can be performed.

[0217] Step 1: The terminal device resets the first type of counters and / or timers in the first protocol stack. The first type of counters and / or timers are related to polling.

[0218] In some embodiments, when the first network device has a first protocol stack, the terminal device resets the first type of counters and / or timers of the first protocol stack.

[0219] In some embodiments, if the first network device does not have a first protocol stack, the terminal device does not reset the first type of counters and / or timers of the first protocol stack.

[0220] In some embodiments, the first type of counter and / or timer includes, but is not limited to, at least one of the following:

[0221] The first counter is used to store the highest sequence number (SN) value of the PDU submitted to the lower-level protocol stack.

[0222] The second counter is used to count the number of PDUs sent since the last polling bit was transmitted;

[0223] The third counter is used to calculate the number of data bytes sent since the last polling bit was transmitted.

[0224] The first timer is used to retransmit polling.

[0225] Using the above method, polling-related operations can resume normally after cell handover.

[0226] Step 2: The terminal device resets the second type of counters and / or timers in the first protocol stack, which are related to retransmission.

[0227] In some embodiments, if the first network device has a first protocol stack, the terminal device resets the second type of counters and / or timers of the first protocol stack.

[0228] In some embodiments, if the first network device does not have a first protocol stack, the terminal device does not reset the second type of counters and / or timers of the first protocol stack.

[0229] In some embodiments, the second type of counter and / or timer includes, but is not limited to, a fourth counter used to calculate the number of retransmissions of an RLC SDU or an RLC SDU segment.

[0230] Using the above method, retransmission-related operations can be restarted normally after cell handover.

[0231] In the above method embodiments, the technical solution of this application has been described and explained only from the perspective of the interaction between the terminal device and the network device. The steps performed by the terminal device described above can be implemented independently as a data transmission method on the terminal device side, and the steps performed by the network device described above can be implemented independently as a data transmission method on the network device side. Furthermore, the embodiments provided herein can be arbitrarily combined to form new embodiments, all of which are within the protection scope of this application.

[0232] The following are embodiments of the apparatus described in this application, which can be used to execute the embodiments of the method described in this application. For details not disclosed in the apparatus embodiments of this application, please refer to the embodiments of the method described in this application.

[0233] Please refer to Figure 6, which shows a block diagram of a data transmission apparatus provided in one embodiment of this application. This apparatus has the function of implementing the data transmission method example described above. This function can be implemented in hardware or by hardware executing corresponding software. The apparatus can be the terminal device described above, or it can be installed within a terminal device. As shown in Figure 6, the apparatus 600 may include a processing module 610.

[0234] The processing module 610 is used to control the first protocol stack to transmit or retransmit the first type of data packet to the first network device. The upper layer protocol stack of the first protocol stack is the RRC layer, the SDAP layer, or the IP layer, and the lower layer protocol stack of the first protocol stack is the MAC layer. The first network device is the network device where the target cell where the terminal device camps after cell handover is located.

[0235] In some embodiments, the first type of data packet includes at least one of the following:

[0236] Data packets that were not acknowledged as received by the first network device;

[0237] Data packets that are not acknowledged for receipt by the second network device, where the second network device is the network device where the source cell where the terminal device camped before the cell handover is located;

[0238] Data packets following the first data packet that was not acknowledged by the first network device;

[0239] Data packets following the first data packet that was not acknowledged by the second network device;

[0240] Data packets that are not delivered to the underlying protocol stack, where the underlying protocol stack refers to the protocol stack at the bottom of the first protocol stack.

[0241] In some embodiments, the transmission or retransmission of data packets that have not been delivered to the underlying protocol stack is performed in Unacknowledged Mode (UM).

[0242] In some embodiments, the device 600 further includes a receiving module (not shown).

[0243] The receiving module is used to receive first information, which is used to indicate the data packet reception status.

[0244] The processing module 610 is further configured to determine, based on the first information, a second type of data packet that needs to be retransmitted.

[0245] In some embodiments, the receiving module is further configured to receive second information, the second information being used to indicate a second type of data packet that needs to be retransmitted.

[0246] In some embodiments, the second type of data packet includes at least one of the following:

[0247] The data packet that is acknowledged as received by the first network device;

[0248] The data packet acknowledged and received by the second network device, which is the network device where the source cell where the terminal device camped before the cell handover was performed;

[0249] Data packets following the first data packet that was not acknowledged by the first network device;

[0250] The data packet following the first data packet that was not acknowledged by the second network device.

[0251] In some embodiments, the first information is transmitted during cell handover; or...

[0252] The first information is transmitted during the data transmission process.

[0253] In some embodiments, the first network device has the first protocol stack; or...

[0254] The first network device does not have the first protocol stack.

[0255] In some embodiments, when the first network device and the second network device are different network devices, the receiving module is further configured to receive third information, the third information being used to instruct the terminal device to reset the header compression algorithm of the first protocol stack, the header compression algorithm being used to compress the header, and the second network device being the network device where the source cell to which the terminal device connected before cell handover is located.

[0256] In some embodiments, the third information is used to indicate at least one of the following:

[0257] The terminal device performs the reconstruction operation of the first protocol stack;

[0258] Reset the header compression algorithm of the first protocol stack.

[0259] In some embodiments, the header compression algorithm includes at least one of the following: ROHC, EHC; or,

[0260] The message header is compressed using the UDC algorithm.

[0261] In some embodiments, when the first network device and the second network device are different network devices, the receiving module is further configured to receive fourth information from the first network device, the fourth information being used to instruct the terminal device to update the key, the key being used to securely protect the data packet, and the second network device being the network device where the source cell to which the terminal device was connected before the cell handover is located.

[0262] In some embodiments, the fourth information is used to indicate at least one of the following:

[0263] The terminal device performs the reconstruction operation of the first protocol stack;

[0264] Update the key.

[0265] In some embodiments, the fourth information is used to explicitly or implicitly indicate whether the terminal device needs to update the key.

[0266] In some embodiments, the fourth information is used to indicate the identification information of the group to which the target cell belongs, and the target cell is the cell that the terminal device connects to after handover.

[0267] In some embodiments, if the identifier information of the target cell group indicated by the fourth information is the same as the identifier information of the source cell group, the key is not updated; or,

[0268] If the identifier information of the target cell group indicated by the fourth information is different from the identifier information of the source cell group, the key is updated.

[0269] The target cell is the cell that the terminal device connects to after the handover, and the source cell is the cell that the terminal device connected to before the handover.

[0270] In some embodiments, when the first network device and the second network device are different network devices, the processing module 610 is further configured to clear a third type of data packet, the third type of data packet including at least one of the following:

[0271] Protocol Data Units (PDUs) and / or PDU segments in the transmit buffer;

[0272] PDU segments in the receive buffer;

[0273] Data packets that are in the receive buffer but have not been delivered to the upper-layer protocol stack, where the upper-layer protocol stack refers to the protocol stack above the first protocol stack;

[0274] Signaling radio bearer SRB storage service data unit SDU or PDU;

[0275] The second network device is the network device where the source cell where the terminal device camped before the cell handover was performed.

[0276] In some embodiments, when the first network device and the second network device are the same network device, the processing module 610 is further configured to perform at least one of the following:

[0277] Retain the third type of data packet;

[0278] Clear the SDU or PDU stored in the SRB.

[0279] In some embodiments, the third type of data packet includes at least one of the following:

[0280] PDUs and / or PDU segments in the transmit buffer;

[0281] PDU segments in the receive buffer;

[0282] Data packets that are in the receive buffer but have not been delivered to the upper-layer protocol stack, where the upper-layer protocol stack refers to the protocol stack above the first protocol stack;

[0283] The second network device is the network device where the source cell where the terminal device camped before the cell handover was performed.

[0284] In some embodiments, the processing module 610 is further configured to reset a first type of counter and / or timer of the first protocol stack, the first type of counter and / or timer being related to polling.

[0285] In some embodiments, the processing module 610 is further configured to reset the first type counter and / or timer of the first protocol stack when the first network device has the first protocol stack.

[0286] In some embodiments, the processing module 610 is further configured to not reset the first type counter and / or timer of the first protocol stack if the first network device does not have the first protocol stack.

[0287] In some embodiments, the first type of counter and / or timer includes, but is not limited to, at least one of the following:

[0288] The first counter is used to store the highest sequence number (SN) value of the PDU submitted to the lower-layer protocol stack.

[0289] A second counter is used to calculate the number of PDUs sent since the last polling bit was transmitted;

[0290] A third counter is used to calculate the number of data bytes sent since the last polling bit was transmitted;

[0291] The first timer is used to retransmit the polling.

[0292] In some embodiments, the processing module 610 is further configured to reset a second type of counter and / or timer of the first protocol stack, the second type of counter and / or timer being associated with retransmission.

[0293] In some embodiments, the processing module 610 is further configured to reset a second type of counter and / or timer of the first protocol stack when the first network device has the first protocol stack.

[0294] In some embodiments, the processing module 610 is further configured to not reset the second type of counters and / or timers of the first protocol stack if the first network device does not have the first protocol stack.

[0295] In some embodiments, the second type of counter and / or timer includes, but is not limited to, a fourth counter used to calculate the number of retransmissions of an RLC SDU or an RLC SDU segment.

[0296] In some embodiments, the first information includes the reception status of data segments.

[0297] In some embodiments, when the first network device has the first protocol stack, the first information includes the reception status of data segments.

[0298] In some embodiments, if the first network device does not have the first protocol stack, the first information does not include the data segmentation reception status.

[0299] The technical solution provided in this application presents a novel protocol stack structure. The terminal device uses a first protocol stack to transmit or retransmit data packets. The lower protocol stack of the first protocol stack is the MAC layer, and the upper protocol stack is either the SDAP layer, RRC layer, or IP layer. By using only one data layer (the first protocol stack) to process transmitted data, functional duplication between multiple protocol stacks is avoided, which helps reduce the complexity of data processing in the terminal device.

[0300] Please refer to Figure 7, which shows a block diagram of a data transmission apparatus provided in one embodiment of this application. This apparatus has the function of implementing the data transmission method example described above; the function can be implemented by hardware or by hardware executing corresponding software. This apparatus can be a network device as described above, or it can be installed within a network device. As shown in Figure 7, the apparatus 700 may include a receiving module 710.

[0301] The receiving module 710 is used to receive a first type of data packet transmitted or retransmitted by the first protocol stack of the terminal device. The upper layer protocol stack of the first protocol stack is the RRC layer, the SDAP layer, or the IP layer, and the lower layer protocol stack of the first protocol stack is the MAC layer. The first network device is the network device where the target cell where the terminal device camps after cell handover is located.

[0302] In some embodiments, the first type of data packet includes at least one of the following:

[0303] Data packets that were not acknowledged as received by the first network device;

[0304] Data packets that are not acknowledged for receipt by the second network device, where the second network device is the network device where the source cell where the terminal device camped before the cell handover is located;

[0305] Data packets following the first data packet that was not acknowledged by the first network device;

[0306] Data packets following the first data packet that was not acknowledged by the second network device;

[0307] Data packets that are not delivered to the underlying protocol stack, where the underlying protocol stack refers to the protocol stack at the bottom of the first protocol stack.

[0308] In some embodiments, the transmission or retransmission of data packets that have not been delivered to the underlying protocol stack is performed in Unacknowledged Mode (UM).

[0309] In some embodiments, the device 700 further includes a transmitting module (not shown).

[0310] The sending module is used to send first information, which is used to indicate the data packet reception status.

[0311] In some embodiments, the sending module is further configured to send second information, the second information being used to indicate a second type of data packet that needs to be retransmitted.

[0312] In some embodiments, the second type of data packet includes at least one of the following:

[0313] The data packet that is acknowledged as received by the first network device;

[0314] The data packet acknowledged and received by the second network device, which is the network device where the source cell where the terminal device camped before the cell handover was performed;

[0315] Data packets following the first data packet that was not acknowledged by the first network device;

[0316] The data packet following the first data packet that was not acknowledged by the second network device.

[0317] In some embodiments, the first information is transmitted during cell handover; or...

[0318] The first information is transmitted during the data transmission process.

[0319] In some embodiments, the first network device has the first protocol stack; or...

[0320] The first network device does not have the first protocol stack.

[0321] In some embodiments, when the first network device and the second network device are different network devices, the sending module is configured to send third information, the third information being used to instruct the terminal device to reset the header compression algorithm of the first protocol stack, the header compression algorithm being used to compress the header, and the second network device being the network device where the source cell to which the terminal device connected before cell handover is located.

[0322] In some embodiments, the third information is used to indicate at least one of the following:

[0323] The terminal device performs the reconstruction operation of the first protocol stack;

[0324] Reset the header compression algorithm of the first protocol stack.

[0325] In some embodiments, the header compression algorithm includes at least one of the following: ROHC, EHC; or,

[0326] The message header is compressed using the UDC algorithm.

[0327] In some embodiments, when the first network device and the second network device are different network devices, the sending module is further configured to send fourth information, the fourth information being used to instruct the terminal device to update the key, the key being used to securely protect the data packet, and the second network device being the network device where the source cell to which the terminal device connected before cell handover is located.

[0328] In some embodiments, the fourth information is used to indicate at least one of the following:

[0329] The terminal device performs the reconstruction operation of the first protocol stack;

[0330] Update the key.

[0331] In some embodiments, the fourth information is used to explicitly or implicitly indicate whether the terminal device needs to update the key.

[0332] In some embodiments, the fourth information is used to indicate the identification information of the packet in the target cell, wherein the target cell is the cell to which the terminal device connects after handover.

[0333] In some embodiments, if the identifier information of the target cell group indicated by the fourth information is the same as the identifier information of the source cell group, the terminal device does not update the key; or...

[0334] If the identifier information of the target cell group indicated by the fourth information is different from the identifier information of the source cell group, the terminal device updates the key;

[0335] The target cell is the cell that the terminal device connects to after the handover, and the source cell is the cell that the terminal device connected to before the handover.

[0336] In some embodiments, when the first network device and the second network device are different network devices, the terminal device clears a third type of data packet, which includes at least one of the following:

[0337] Protocol Data Units (PDUs) and / or PDU segments in the transmit buffer;

[0338] PDU segments in the receive buffer;

[0339] Data packets that are not delivered to the upper-layer protocol stack, where the upper-layer protocol stack refers to the protocol stack above the first protocol stack;

[0340] Signaling radio bearer SRB storage service data unit SDU or PDU;

[0341] The second network device is the network device where the source cell where the terminal device camped before the cell handover was performed.

[0342] In some embodiments, when the first network device and the second network device are the same network device...

[0343] The terminal device retains the third type of data packets; and / or,

[0344] The terminal device clears the SDU or PDU stored in the SRB.

[0345] In some embodiments, the third type of data packet includes at least one of the following:

[0346] PDUs and / or PDU segments in the transmit buffer;

[0347] PDU segments in the receive buffer;

[0348] Data packets that are in the receive buffer but have not been delivered to the upper-layer protocol stack, where the upper-layer protocol stack refers to the protocol stack above the first protocol stack;

[0349] The second network device is the network device where the source cell where the terminal device camped before the cell handover was performed.

[0350] In some embodiments, the terminal device resets a first type of counter and / or timer of the first protocol stack, the first type of counter and / or timer being related to polling.

[0351] In some embodiments, when the first network device has the first protocol stack, the terminal device resets the first type of counter and / or timer of the first protocol stack.

[0352] In some embodiments, the terminal device does not reset the first type of counter and / or timer of the first protocol stack when the first network device does not have the first protocol stack.

[0353] In some embodiments, the first type of counter and / or timer includes, but is not limited to, at least one of the following:

[0354] The first counter is used to store the highest sequence number (SN) value of the PDU submitted to the lower-layer protocol stack.

[0355] A second counter is used to calculate the number of PDUs sent since the last polling bit was transmitted;

[0356] A third counter is used to calculate the number of data bytes sent since the last polling bit was transmitted;

[0357] The first timer is used to retransmit the polling.

[0358] In some embodiments, the terminal device resets a second type of counter and / or timer of the first protocol stack, the second type of counter and / or timer being associated with retransmission.

[0359] In some embodiments, when the first network device has the first protocol stack, the terminal device resets the second type of counters and / or timers of the first protocol stack.

[0360] In some embodiments, if the first network device does not have the first protocol stack, the terminal device does not reset the second type of counters and / or timers of the first protocol stack.

[0361] In some embodiments, the second type of counter and / or timer includes, but is not limited to, a fourth counter used to calculate the number of retransmissions of an RLC SDU or an RLC SDU segment.

[0362] In some embodiments, the first information includes the reception status of data segments.

[0363] In some embodiments, when the first network device has the first protocol stack, the first information includes the reception status of data segments.

[0364] In some embodiments, if the first network device does not have the first protocol stack, the first information does not include the data segmentation reception status.

[0365] The technical solution provided in this application presents a novel protocol stack structure. The terminal device uses a first protocol stack to transmit or retransmit data packets. The lower protocol stack of the first protocol stack is the MAC layer, and the upper protocol stack is either the SDAP layer, RRC layer, or IP layer. By using only one data layer (the first protocol stack) to process transmitted data, functional duplication between multiple protocol stacks is avoided, which helps reduce the complexity of data processing in the terminal device.

[0366] It should be noted that the device provided in the above embodiments is only illustrated by the division of the above functional modules when implementing its functions. In actual applications, the above functions can be assigned to different functional modules according to actual needs, that is, the content structure of the device can be divided into different functional modules to complete all or part of the functions described above.

[0367] Regarding the apparatus in the above embodiments, the specific manner in which each module performs its operation has been described in detail in the embodiments related to the method, and will not be elaborated upon here.

[0368] Please refer to Figure 8, which shows a schematic diagram of a communication device provided in one embodiment of this application. The communication device can be a terminal device or a network device as described above. The communication device 800 may include a processor 801, a transceiver 802, and a memory 803. The transceiver 802 is used to implement sending or receiving functions, such as implementing the functions of the receiving module 710 described above, or implementing the functions of the sending module described above. The processor 801 can be used to implement other processing functions or control sending and / or receiving, such as implementing the functions of the processing module 610 described above.

[0369] The processor 801 includes one or more processing cores. The processor 801 executes various functional applications and information processing by running software programs and modules.

[0370] The transceiver 802 may include a receiver and a transmitter. For example, the receiver and transmitter may be implemented as the same wireless communication component, which may include a wireless communication chip and a radio frequency antenna.

[0371] The memory 803 can be connected to the processor 801 and the transceiver 802.

[0372] The memory 803 can be used to store a computer program executed by the processor, and the processor 801 is used to execute the computer program to implement the various steps in the above method embodiments.

[0373] In some embodiments, when the communication device 800 is a terminal device, the processor 801 is used to control the first protocol stack to transmit or retransmit the first type of data packet to the first network device. The upper layer protocol stack of the first protocol stack is the RRC layer, the SDAP layer, or the IP layer, and the lower layer protocol stack of the first protocol stack is the MAC layer. The first network device is the network device where the target cell where the terminal device camps after cell handover is located.

[0374] In some embodiments, when the communication device 800 is a network device, the transceiver 802 is used to receive a first type of data packet transmitted or retransmitted by the first protocol stack of the terminal device. The upper protocol stack of the first protocol stack is the RRC layer, the SDAP layer, or the IP layer, and the lower protocol stack of the first protocol stack is the MAC layer. The first network device is the network device where the target cell where the terminal device camps after cell handover is located.

[0375] For details not described in this embodiment, please refer to the embodiments above, which will not be repeated here.

[0376] Furthermore, the memory can be implemented by any type of volatile or non-volatile storage device or a combination thereof, including but not limited to: magnetic disks or optical disks, electrically erasable programmable read-only memory, erasable programmable read-only memory, statically accessible memory, read-only memory, magnetic memory, flash memory, and programmable read-only memory.

[0377] This application embodiment also provides a computer-readable storage medium storing a computer program. The computer program is executed by a processor to implement the data transmission and reception methods on the terminal device side or the network device side. Optionally, the computer-readable storage medium may include ROM (Read-Only Memory), RAM (Random-Access Memory), SSD (Solid State Drives), or optical disc, etc. The random access memory may include ReRAM (Resistance Random Access Memory) and DRAM (Dynamic Random Access Memory).

[0378] This application also provides a chip, which includes programmable logic circuits and / or program instructions. When the chip is running, it is used to implement the data transmission method on the first device side or the data transmission method on the second device side.

[0379] This application also provides a computer program product, which includes a computer program stored in a computer-readable storage medium. A processor reads and executes the computer program from the computer-readable storage medium to implement the data transmission method on the first device side or the data transmission method on the second device side.

[0380] It should be understood that the term "instruction" mentioned in the embodiments of this application can be a direct instruction, an indirect instruction, or an indication of a relationship. For example, A instructing B can mean that A directly instructs B, such as B being able to obtain information through A; it can also mean that A indirectly instructs B, such as A instructing C, so B can obtain information through C; or it can mean that there is a relationship between A and B.

[0381] In the description of the embodiments of this application, the term "correspondence" may indicate that there is a direct or indirect correspondence between two things, or that there is an association between two things, or that there is a relationship of instruction and being instructed, configuration and being configured, etc.

[0382] In some embodiments of this application, "predefined" can be implemented by pre-storing corresponding codes, tables, or other means that can be used to indicate relevant information in the device (e.g., including terminal devices and APs). This application does not limit the specific implementation method. For example, predefined can refer to what is defined in the protocol.

[0383] In some embodiments of this application, the term "protocol" may refer to standard protocols in the field of communications, such as LTE protocols, NR protocols, and related protocols applied in future communication systems. This application does not limit the scope of these protocols.

[0384] In this article, "multiple" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0385] In this article, "greater than or equal to" can mean greater than or equal to, and "less than or equal to" can mean less than or equal to.

[0386] Furthermore, the step numbers described herein are merely illustrative of one possible execution order between steps. In some other embodiments, the steps may not be executed in the order of their numbers, such as two steps with different numbers being executed simultaneously, or two steps with different numbers being executed in the reverse order of the illustration. This application does not limit this.

[0387] Those skilled in the art will recognize that the functions described in the embodiments of this application in one or more of the above examples can be implemented using hardware, software, firmware, or any combination thereof. When implemented using software, these functions can be stored in a computer-readable medium or transmitted as one or more instructions or code on a computer-readable medium. Computer-readable media include computer storage media and communication media, wherein communication media include any medium that facilitates the transfer of a computer program from one place to another. Storage media can be any available medium that can be accessed by a general-purpose or special-purpose computer.

[0388] The above description is merely an exemplary embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A data transmission method, characterized in that, The method is executed by a terminal device, and the method includes: The system controls the first protocol stack to transmit or retransmit the first type of data packets to the first network device. The upper layer protocol stack of the first protocol stack is the Radio Resource Control (RRC) layer, the Service Data Adaptation Protocol (SDAP) layer, or the Internet Protocol (IP) layer. The lower layer protocol stack of the first protocol stack is the Media Access Control (MAC) layer. The first network device is the network device where the target cell where the terminal device camps after cell handover is located.

2. The method according to claim 1, characterized in that, The first type of data packet includes at least one of the following: Data packets that were not acknowledged as received by the first network device; Data packets that are not acknowledged for receipt by the second network device, where the second network device is the network device where the source cell where the terminal device camped before the cell handover is located; Data packets following the first data packet that was not acknowledged by the first network device; Data packets following the first data packet that was not acknowledged by the second network device; Data packets that are not delivered to the underlying protocol stack, where the underlying protocol stack refers to the protocol stack at the bottom of the first protocol stack.

3. The method according to claim 2, characterized in that, The transmission or retransmission of data packets that are not delivered to the underlying protocol stack is performed in Unacknowledged Mode (UM).

4. The method according to any one of claims 1 to 3, characterized in that, The method further includes: Receive first information, which is used to indicate the data packet reception status; Based on the first information, it is determined that the second type of data packet needs to be retransmitted.

5. The method according to any one of claims 1 to 4, characterized in that, The method further includes: Receive second information, which indicates that a second type of data packet needs to be retransmitted.

6. The method according to claim 4 or 5, characterized in that, The second type of data packet includes at least one of the following: The data packet that is acknowledged as received by the first network device; The data packet acknowledged and received by the second network device, which is the network device where the source cell where the terminal device camped before the cell handover was performed; Data packets following the first data packet that was not acknowledged by the first network device; The data packet following the first data packet that was not acknowledged by the second network device.

7. The method according to any one of claims 4 to 6, characterized in that, The first information is transmitted during cell handover; or, The first information is transmitted during the data transmission process.

8. The method according to any one of claims 1 to 7, characterized in that, The first network device has the first protocol stack; or, The first network device does not have the first protocol stack.

9. The method according to any one of claims 1 to 8, characterized in that, When the first network device and the second network device are different network devices, the method further includes: The terminal device receives third information, which is used to instruct the terminal device to reset the header compression algorithm of the first protocol stack. The header compression algorithm is used to compress the header. The second network device is the network device where the source cell that the terminal device connected to before cell handover is located.

10. The method according to claim 9, characterized in that, The third information is used to indicate at least one of the following The terminal device performs the reconstruction operation of the first protocol stack; Reset the header compression algorithm of the first protocol stack.

11. The method according to claim 9 or 10, characterized in that, The packet header compression algorithm includes at least one of the following: IP packet header compression ROHC, Ethernet packet header compression EHC; or... The message header is compressed using the uplink data compression UDC algorithm.

12. The method according to any one of claims 1 to 11, characterized in that, When the first network device and the second network device are different network devices, the method further includes: The terminal device receives fourth information from the first network device, the fourth information being used to instruct the terminal device to update the key, the key being used to securely protect the data packet, and the second network device being the network device where the source cell to which the terminal device connected before the cell handover is located.

13. The method according to claim 12, characterized in that, The fourth piece of information is used to indicate at least one of the following: The terminal device performs the reconstruction operation of the first protocol stack; Update the key.

14. The method according to claim 12 or 13, characterized in that, The fourth piece of information is used to explicitly or implicitly indicate whether the terminal device needs to update the key.

15. The method according to claim 14, characterized in that, The fourth piece of information is used to indicate the identification information of the group to which the target cell belongs, and the target cell is the cell that the terminal device connects to after the handover.

16. The method according to claim 14 or 15, characterized in that, If the identifier information of the target cell group indicated by the fourth information is the same as the identifier information of the source cell group, the key is not updated; or, If the identifier information of the target cell group indicated by the fourth information is different from the identifier information of the source cell group, the key is updated. in, The target cell is the cell that the terminal device connects to after the handover, and the source cell is the cell that the terminal device connected to before the handover.

17. The method according to any one of claims 1 to 16, characterized in that, When the first network device and the second network device are different network devices, the method further includes: Clear the third type of data packets, which includes at least one of the following: Protocol Data Units (PDUs) and / or PDU segments in the transmit buffer; PDUs and / or PDU segments in the receive buffer; Data packets that are in the receive buffer but have not been delivered to the upper-layer protocol stack, where the upper-layer protocol stack refers to the protocol stack above the first protocol stack; Signaling radio bearer SRB storage service data unit SDU or PDU; The second network device is the network device where the source cell where the terminal device camped before the cell handover was performed.

18. The method according to any one of claims 1 to 17, characterized in that, When the first network device and the second network device are the same network device, the method further includes at least one of the following: Retain the third type of data packet; Clear the SDU or PDU stored in the SRB.

19. The method according to claim 18, characterized in that, The third type of data packet includes at least one of the following: PDUs and / or PDU segments in the transmit buffer; PDUs and / or PDU segments in the receive buffer; Data packets that are in the receive buffer but have not been delivered to the upper-layer protocol stack, where the upper-layer protocol stack refers to the protocol stack above the first protocol stack; The second network device is the network device where the source cell where the terminal device camped before the cell handover was performed.

20. The method according to any one of claims 1 to 19, characterized in that, The method further includes: Reset the first type of counters and / or timers of the first protocol stack, which are related to polling.

21. The method according to claim 20, characterized in that, The resetting of the first type of counters and / or timers in the first protocol stack includes: If the first network device has the first protocol stack, reset the first type of counters and / or timers of the first protocol stack.

22. The method according to claim 20 or 21, characterized in that, The method further includes: If the first network device does not have the first protocol stack, the first type of counter and / or timer of the first protocol stack will not be reset.

23. The method according to any one of claims 20 to 22, characterized in that, The first type of counters and / or timers includes, but is not limited to, at least one of the following: The first counter is used to store the highest sequence number (SN) value of the PDU submitted to the lower-layer protocol stack. A second counter is used to calculate the number of PDUs sent since the last polling bit was transmitted; A third counter is used to calculate the number of data bytes sent since the last polling bit was transmitted; The first timer is used to retransmit the polling.

24. The method according to any one of claims 1 to 23, characterized in that, The method further includes: Reset the second type of counters and / or timers of the first protocol stack, which are related to retransmission.

25. The method according to claim 24, characterized in that, The resetting of the second type of counters and / or timers of the first protocol stack includes: If the first network device has the first protocol stack, reset the second type of counters and / or timers of the first protocol stack.

26. The method according to claim 24 or 25, characterized in that, The method further includes: If the first network device does not have the first protocol stack, the second type of counters and / or timers of the first protocol stack are not reset.

27. The method according to any one of claims 24 to 26, characterized in that, The second type of counter and / or timer includes, but is not limited to, a fourth counter used to calculate the number of retransmissions of an RLC SDU or an RLC SDU segment.

28. The method according to any one of claims 1 to 27, characterized in that, The first information includes the reception status of data segments.

29. The method according to claim 28, characterized in that, The first information includes the reception status of data segments, including: When the first network device has the first protocol stack, the first information includes the data segment reception status.

30. The method according to claim 28 or 29, characterized in that, If the first network device does not have the first protocol stack, the first information does not include the data segmentation reception status.

31. A data transmission method, characterized in that, The method is performed by a first network device, and the method includes: The terminal device receives a first type of data packet transmitted or retransmitted by the first protocol stack. The upper layer of the first protocol stack is the Radio Resource Control (RRC) layer, the Service Data Adaptation Protocol (SDAP) layer, or the Internet Protocol (IP) layer. The lower layer of the first protocol stack is the Media Access Control (MAC) layer. The first network device is the network device where the target cell where the terminal device camps after cell handover is located.

32. The method according to claim 31, characterized in that, The first type of data packet includes at least one of the following: Data packets that were not acknowledged as received by the first network device; Data packets that are not acknowledged for receipt by the second network device, where the second network device is the network device where the source cell where the terminal device camped before the cell handover is located; Data packets following the first data packet that was not acknowledged by the first network device; Data packets following the first data packet that was not acknowledged by the second network device; Data packets that are not delivered to the underlying protocol stack, where the underlying protocol stack refers to the protocol stack at the bottom of the first protocol stack.

33. The method according to claim 32, characterized in that, The transmission or retransmission of data packets that are not delivered to the underlying protocol stack is performed in the Unacknowledged Mode (UM).

34. The method according to any one of claims 31 to 33, characterized in that, The method further includes: Send a first message, which is used to indicate the status of data packet reception.

35. The method according to any one of claims 31 to 34, characterized in that, The method further includes: Send a second message, which indicates that a second type of data packet needs to be retransmitted.

36. The method according to claim 34 or 35, characterized in that, The second type of data packet includes at least one of the following: The data packet that is acknowledged as received by the first network device; The data packet acknowledged and received by the second network device, which is the network device where the source cell where the terminal device camped before the cell handover was performed; Data packets following the first data packet that was not acknowledged by the first network device; The data packet following the first data packet that was not acknowledged by the second network device.

37. The method according to any one of claims 34 to 36, characterized in that, The first information is transmitted during cell handover; or, The first information is transmitted during the data transmission process.

38. The method according to any one of claims 31 to 37, characterized in that, The first network device has the first protocol stack; or, The first network device does not have the first protocol stack.

39. The method according to any one of claims 31 to 38, characterized in that, When the first network device and the second network device are different network devices, the method further includes: Send a third message, which is used to instruct the terminal device to reset the header compression algorithm of the first protocol stack. The header compression algorithm is used to compress the header. The second network device is the network device where the source cell that the terminal device connected to before the cell handover is located.

40. The method according to claim 39, characterized in that, The third information is used to indicate at least one of the following: The terminal device performs the reconstruction operation of the first protocol stack; Reset the header compression algorithm of the first protocol stack.

41. The method according to claim 37, characterized in that, The packet header compression algorithm includes at least one of the following: IP packet header compression ROHC, Ethernet packet header compression EHC; or... The message header is compressed using the uplink data compression UDC algorithm.

42. The method according to any one of claims 31 to 41, characterized in that, When the first network device and the second network device are different network devices, the method further includes: Send a fourth message, which is used to instruct the terminal device to update the key. The key is used to protect the data packet. The second network device is the network device where the source cell that the terminal device connected to before the cell handover is located.

43. The method according to claim 42, characterized in that, The fourth piece of information is used to indicate at least one of the following: The terminal device performs the reconstruction operation of the first protocol stack; Update the key.

44. The method according to claim 42 or 43, characterized in that, The fourth piece of information is used to explicitly or implicitly indicate whether the terminal device needs to update the key.

45. The method according to claim 44, characterized in that, The fourth piece of information is used to indicate the identification information of the group in the target cell, which is the cell that the terminal device connects to after the handover.

46. ​​The method according to claim 45, characterized in that, If the identifier information of the target cell group indicated by the fourth information is the same as the identifier information of the source cell group, the terminal device does not update the key; or, If the identifier information of the target cell group indicated by the fourth information is different from the identifier information of the source cell group, the terminal device updates the key; The target cell is the cell that the terminal device connects to after the handover, and the source cell is the cell that the terminal device connected to before the handover.

47. The method according to any one of claims 31 to 46, characterized in that, When the first network device and the second network device are different network devices, the terminal device clears the third type of data packets, which includes at least one of the following: Protocol Data Units (PDUs) and / or PDU segments in the transmit buffer; PDUs and / or PDU segments in the receive buffer; Data packets that are not delivered to the upper-layer protocol stack, where the upper-layer protocol stack refers to the protocol stack above the first protocol stack; Signaling radio bearer SRB storage service data unit SDU or PDU; The second network device is the network device where the source cell where the terminal device camped before the cell handover was performed.

48. The method according to any one of claims 31 to 47, characterized in that, When the first network device and the second network device are the same network device. The terminal device retains the third type of data packets; and / or, The terminal device clears the SDU or PDU stored in the SRB.

49. The method according to claim 48, characterized in that, The third type of data packet includes at least one of the following: PDUs and / or PDU segments in the transmit buffer; PDUs and / or PDU segments in the receive buffer; Data packets that are in the receive buffer but have not been delivered to the upper-layer protocol stack, where the upper-layer protocol stack refers to the protocol stack above the first protocol stack; The second network device is the network device where the source cell where the terminal device camped before the cell handover was performed.

50. The method according to any one of claims 31 to 49, characterized in that, The terminal device resets the first type of counters and / or timers of the first protocol stack, which are related to polling.

51. The method according to claim 50, characterized in that, The terminal device resets the first type of counters and / or timers of the first protocol stack, including: If the first network device has the first protocol stack, the terminal device resets the first type of counter and / or timer of the first protocol stack.

52. The method according to claim 50 or 51, characterized in that, If the first network device does not have the first protocol stack, the terminal device does not reset the first type of counter and / or timer of the first protocol stack.

53. The method according to any one of claims 50 to 52, characterized in that, The first type of counters and / or timers includes, but is not limited to, at least one of the following: The first counter is used to store the highest sequence number (SN) value of the PDU submitted to the lower-layer protocol stack. A second counter is used to calculate the number of PDUs sent since the last polling bit was transmitted; A third counter is used to calculate the number of data bytes sent since the last polling bit was transmitted; The first timer is used to retransmit the polling.

54. The method according to any one of claims 31 to 53, characterized in that, The terminal device resets the second type of counters and / or timers of the first protocol stack, which are related to retransmission.

55. The method according to claim 54, characterized in that, The terminal device resets the second type of counters and / or timers of the first protocol stack, including: If the first network device has the first protocol stack, the terminal device resets the second type of counters and / or timers of the first protocol stack.

56. The method according to claim 54 or 55, characterized in that, The terminal device does not reset the second type of counter and / or timer of the first protocol stack if the first network device does not have the first protocol stack.

57. The method according to any one of claims 54 to 56, characterized in that, The second type of counter and / or timer includes, but is not limited to, a fourth counter used to calculate the number of retransmissions of an RLC SDU or an RLC SDU segment.

58. The method according to any one of claims 31 to 57, characterized in that, The first information includes the reception status of data segments.

59. The method according to claim 58, characterized in that, The first information includes the reception status of data segments, including: When the first network device has the first protocol stack, the first information includes the data segment reception status.

60. The method according to claim 58 or 59, characterized in that, If the first network device does not have the first protocol stack, the first information does not include the data segmentation reception status.

61. A data transmission device, characterized in that, The device includes: The processing module is used to control the transmission or retransmission of the first type of data packets by the first protocol stack. The upper layer protocol stack of the first protocol stack is the Radio Resource Control (RRC) layer, the Service Data Adaptation Protocol (SDAP) layer, or the Internet Protocol (IP) layer. The lower layer protocol stack of the first protocol stack is the Media Access Control (MAC) layer. The first network device is the network device where the target cell where the terminal device camps after cell handover is located.

62. A data transmission device, characterized in that, The device includes: The receiving module is used to receive the first type of data packets transmitted or retransmitted by the first protocol stack of the terminal device. The upper layer protocol stack of the first protocol stack is the Radio Resource Control (RRC) layer, the Service Data Adaptation Protocol (SDAP) layer, or the Internet Protocol (IP) layer. The lower layer protocol stack of the first protocol stack is the Media Access Control (MAC) layer. The first network device is the network device where the target cell where the terminal device camps after cell handover is located.

63. A communication device, characterized in that, The communication device includes a processor and a memory, the memory storing a computer program, the processor executing the computer program to implement the method as claimed in any one of claims 1 to 30, or to implement the method as claimed in any one of claims 31 to 60.

64. A computer-readable storage medium, characterized in that, The storage medium stores a computer program that is executed by a processor to implement the method as claimed in any one of claims 1 to 30, or to implement the method as claimed in any one of claims 31 to 60.

65. A chip, characterized in that, The chip includes programmable logic circuitry and / or program instructions, which, when the chip is running, are used to implement the method as described in any one of claims 1 to 30, or to implement the method as described in any one of claims 31 to 60.

66. A computer program product, characterized in that, The computer program product includes computer instructions stored in a computer-readable storage medium, which a processor reads from and executes to implement the method as claimed in any one of claims 1 to 30, or the method as claimed in any one of claims 31 to 60.

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