Data transmission method and apparatus, terminal, network side device, and readable storage medium

Abstract

The present application relates to the technical field of communications, and discloses a data transmission method and apparatus, a terminal, a network side device, and a readable storage medium. The data transmission method in embodiments of the present application comprises: when a terminal switches from a first cell to a second cell, a first protocol layer entity of a receiving end receives indication information from a sending end, wherein the indication information is used for indicating related information of a first PDU of a first bearer sent by the sending end in the second cell, and the first bearer is a bearer corresponding to the first protocol layer entity; and when the first protocol layer entity has received the first PDU, the first protocol layer entity delivers at least one first service data unit (SDU) to an upper layer, wherein the first SDU is an SDU corresponding to the PDU that has been received, and when the receiving end is the terminal, the sending end is a network side device corresponding to the second cell, or when the sending end is the terminal, the receiving end is a network side device corresponding to the second cell.

Description

Data transmission method and device, terminal, network side equipment and readable storage medium

[0001] The present application claims priority from the Chinese patent application No. 202411326214.8 filed on September 23, 2024, and entitled "Data transmission method and device, terminal, network side equipment and readable storage medium", the whole content of which is incorporated herein by reference. TECHNICAL FIELD

[0002] The present application belongs to the field of communication technology, and particularly relates to a data transmission method, device, terminal, network side equipment and readable storage medium. BACKGROUND

[0003] Currently, in the process of data transmission between a terminal and a network side equipment, the packet data convergence protocol (PDCP) layer of the receiving end (i.e. the terminal or the network side equipment) can determine the count value corresponding to one PDCP data protocol data unit (PDU) sent by the radio link control (RLC) layer in the case of receiving the one PDCP data PDU, and determine whether there are some PDCP data PDUs that have not been received according to the count value. Thus, in the case of determining that there are the some PDCP data PDUs, the terminal can start a timer t-Reordering, and in the case of the t-Reordering timeout (or the t-Reordering not timeout, and the some PDCP data PDUs are received), the terminal can submit the processed PDCP service data unit (SDU) to the upper layer.

[0004] However, since the terminal may perform cell switching in the process of data transmission between the terminal and the network side equipment, the time delay of the PDCP layer of the receiving end submitting the processed PDCP SDU to the upper layer may be large at this time, thus resulting in large time delay of data transmission. SUMMARY

[0005] The present application provides a data transmission method, device, terminal, network side equipment and readable storage medium, which can solve the problem of large time delay of data transmission.

[0006] In a first aspect, a data transmission method is provided. The method comprises: in a case where a terminal is handed over from a first cell to a second cell, receiving, by a first protocol layer entity of the terminal, indication information from a sending terminal, the indication information being used to indicate related information of a first PDU of a first bearer transmitted by the sending terminal in the second cell, the first bearer being a bearer corresponding to the first protocol layer entity; and in a case where the first PDU has been received by the first protocol layer entity, submitting, by the first protocol layer entity, at least one first service data unit (SDU) to a higher layer, the first SDU being an SDU corresponding to the received PDU. In a case where the receiving terminal is the terminal, the sending terminal is a network side device corresponding to the second cell; or in a case where the sending terminal is the terminal, the receiving terminal is the network side device corresponding to the second cell.

[0007] In a second aspect, a data transmission apparatus is provided. The data transmission apparatus comprises: a receiving module and a processing module. The receiving module is configured to, in a case where a terminal is handed over from a first cell to a second cell, receive indication information from a sending terminal, the indication information being used to indicate related information of a first PDU of a first bearer transmitted by the sending terminal in the second cell, the first bearer being a bearer corresponding to the data transmission apparatus. The processing module is configured to, in a case where the first PDU has been received by the data transmission apparatus, submit at least one first SDU to a higher layer, the first SDU being an SDU corresponding to the received PDU. In a case where the receiving terminal is the terminal, the sending terminal is a network side device corresponding to the second cell; or in a case where the sending terminal is the terminal, the receiving terminal is the network side device corresponding to the second cell.

[0008] In a third aspect, a data transmission apparatus is provided. The apparatus is configured to perform the steps of the method of the first aspect.

[0009] In a fourth aspect, a terminal is provided. The terminal comprises a processor and a memory. The memory stores programs or instructions executable on the processor. When the programs or instructions are executed by the processor, the steps of the method of the first aspect are implemented.

[0010] In a fifth aspect, a terminal is provided. The terminal comprises a processor and a communication interface. The communication interface is configured to, in a case where the terminal is handed over from a first cell to a second cell, receive indication information from a sending terminal, the indication information being used to indicate related information of a first PDU of a first bearer transmitted by the sending terminal in the second cell, the first bearer being a bearer corresponding to a first protocol layer entity of the terminal. The processor is configured to, in a case where the first PDU has been received by the first protocol layer entity, submit at least one first service data unit (SDU) to a higher layer, the first SDU being an SDU corresponding to the received PDU. In a case where the receiving terminal is the terminal, the sending terminal is a network side device corresponding to the second cell; or in a case where the sending terminal is the terminal, the receiving terminal is the network side device corresponding to the second cell.

[0011] In a sixth aspect, a network-side device is provided, which includes a processor and a memory, the memory storing programs or instructions executable on the processor, and the programs or instructions, when executed by the processor, implement the steps of the method according to the first aspect.

[0012] In a seventh aspect, a network-side device is provided, which includes a processor and a communication interface, wherein the communication interface is configured to receive, in a case where a terminal is handed over from a first cell to a second cell, indication information from a sending terminal, the indication information being used to indicate related information of a first PDU of a first bearer sent by the sending terminal in the second cell, the first bearer being a bearer corresponding to a first protocol layer entity of the terminal; and the processor is configured to, in a case where the first protocol layer entity has received the first PDU, submit at least one first service data unit (SDU) to a higher layer, the first SDU being an SDU corresponding to the received PDU; wherein the sending terminal is the terminal, and the network-side device corresponds to the second cell.

[0013] In an eighth aspect, a readable storage medium is provided, which stores programs or instructions, and the programs or instructions, when executed by a processor, implement the steps of the method according to the first aspect.

[0014] In a ninth aspect, a chip is provided, which includes a processor and a communication interface, the communication interface being coupled to the processor, and the processor being configured to run programs or instructions to implement the steps of the method according to the first aspect.

[0015] In a tenth aspect, a computer program / program product is provided, which is stored in a storage medium, and the computer program / program product is executed by at least one processor to implement the steps of the method according to the first aspect.

[0016] In the embodiment of the present application, in the case that the terminal is handed over from the first cell to the second cell, the first protocol layer entity of the receiving end receives the information about the first PDU of the first bearer transmitted by the sending end in the second cell from the sending end, the first bearer being the bearer corresponding to the first protocol layer entity, and submits at least one SDU corresponding to the received PDU to the upper layer in the case that the first protocol layer entity has received the first PDU; wherein, in the case that the receiving end is the terminal, the sending end is the network side device corresponding to the second cell; or in the case that the sending end is the terminal, the receiving end is the network side device corresponding to the second cell. Since in the case that the terminal is handed over from the first cell to the second cell, the first protocol layer entity can know the information about the first PDU of the first bearer transmitted by the sending end in the second cell through the indication information, so in the case that the first protocol layer entity receives the first PDU in the case that there are some PDCP data PDUs not received due to the terminal being handed over from the first cell to the second cell, the first protocol layer entity can directly submit at least one SDU (i.e. the processed SDU) corresponding to the received PDU to the upper layer without waiting for t-Reordering timeout, thus the time required for submitting the processed SDU to the upper layer can be reduced, so that the transmission delay of the SDU can be reduced, and thus the transmission delay of the data can be improved. BRIEF DESCRIPTION OF DRAWINGS

[0017] FIG. 1 is a schematic diagram of the architecture of CU-DU in the related art;

[0018] FIG. 2 is a block diagram of a wireless communication system according to an embodiment of the present application;

[0019] FIG. 3 is a schematic diagram of a data transmission method according to an embodiment of the present application;

[0020] FIG. 4 is a schematic diagram of a data transmission method according to another embodiment of the present application;

[0021] FIG. 5A is a schematic diagram of the structure of a data PDU according to an embodiment of the present application;

[0022] FIG. 5B is a schematic diagram of the structure of a data PDU according to another embodiment of the present application;

[0023] FIG. 5C is a schematic diagram of the structure of a data PDU according to another embodiment of the present application;

[0024] FIG. 6 is a schematic diagram of the structure of a data transmission apparatus according to an embodiment of the present application;

[0025] FIG. 7 is a schematic diagram of the hardware structure of a communication device according to an embodiment of the present application;

[0026] FIG. 8 is a schematic diagram of the hardware structure of a terminal according to an embodiment of the present application;

[0027] FIG. 9 is a schematic diagram of a hardware structure of a network side device according to an embodiment of the present application. DETAILED DESCRIPTION

[0028] The technical solutions in the embodiments of the present application will be clearly described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art belong to the scope of protection of the present application.

[0029] The professional terms involved in the embodiments of the present application will be described below.

[0030] 1. Central Unit-Distributed Unit (CU-DU) architecture

[0031] At present, a New Radio (NR) access network splits a Next Generation NodeB (gNB) into a Next Generation NodeB-Central Unit (gNB-CU) and a Next Generation NodeB-Distributed Unit (gNB-DU), and connects them through an F1 interface. The architecture schematic diagram of the CU-DU is shown in FIG. 1.

[0032] Among them, one gNB only contains one CU, contains one or more DUs, and one DU contains one or more cells (Cells).

[0033] The CU contains a protocol stack of PDCP and above, and the DU contains a protocol stack below the PDCP layer (for example, a Radio Link Control (RLC) layer, a Media Access Control (MAC) layer, and a Physical (PHY) layer, etc.).

[0034] In the control plane, the CU contains a Radio Resource Control (RRC) layer and a PDCP in the control plane (PDCP-C).

[0035] In the user plane, the CU contains a Service data adaptation protocol (SDAP) layer and a PDCP in the user plane (PDCP-U).

[0036] 2. Cell switch

[0037] Cell switch includes:

[0038] Intra-CU switch, i.e. source cell and target cell are in the same CU, since PDCP location is unchanged, no key change is needed during the switch procedure;

[0039] Inter-CU switch, i.e. source cell and target cell are in different CU, key change is needed during the switch procedure.

[0040] The existing cell change method in 5th Generation (5G) NR includes: th

[0041] RRC triggered L3 switch, i.e. ReconfigurationWithSync is carried in RRC reconfiguration signaling to instruct the terminal to perform switch or PSCell change;

[0042] Conditional Handover (CHO) / Conditional PSCell Change (CPC) / Layer 1 / Layer 2-Triggered Mobility (LTM), i.e. RRC pre-configures at least one candidate target cell, the terminal evaluates the switch execution condition of the candidate cell, and when the condition is met, the terminal initiates switch or PSCell change;

[0043] LTM (Layer 1 / Layer 2-Triggered Mobility, L1 / L2-Triggered Mobility) cell switch, i.e. RRC pre-configures at least one candidate target cell, and the DU sends a MAC control element (CE) to instruct the terminal to perform switch or PSCell change.

[0044] 3. PDCP

[0045] The PDCP layer is responsible for data packet encryption and integrity protection, and the COUNT value associated with the PDCP SDU is one of the algorithm inputs for the above processes, so when the key is unchanged, the same COUNT value cannot be used to encrypt or protect different PDCP SDUs to ensure the security of data packet transmission.

[0046] Generally, when outOfOrderDelivery is not configured, the PDCP layer needs to ensure that the received data packets are delivered to the upper layer in order, and its receiving end processing mechanism is as follows:

[0047] ​In case of in-sequence delivery is configured at the receiving side, the receiving entity of PDCP at the receiving side needs to maintain the following state variables:

[0048] RX_DELIV: This variable indicates the COUNT value of the first PDCP SDU which has not been delivered to upper layers but is waiting for delivery.

[0049] RX_NEXT: This variable indicates the COUNT value of the PDCP data PDU which is expected to be received next, wherein the PDCP data PDU corresponding to the PDCP SDU can be understood as the PDCP SDU is processed by the PDCP layer for the PDCP data PDU.

[0050] RX_REORD: This variable indicates the COUNT+1 of the PDCP data PDU which triggers the t-Reordering timer, i.e. RX_NEXT at this time.

[0051] When the receiving entity of PDCP receives a PDCP data PDU delivered by RLC layer, it calculates the RCVD_COUNT of the PDU, and after completing the corresponding decryption and integrity check processing, the following operations are performed:

[0052] A1. If RCVD_COUNT < RX_DELIV or the COUNT=RCVD_COUNT which has been received has been received, the PDCP PDU is discarded, and if it is not discarded, the following processing is continued.

[0053] B1. If RCVD_COUNT >= RX_NEXT, RX_NEXT=RCVD_COUNT+1 is updated.

[0054] C1. If RCVD_COUNT=RX_DELIV, the processed PDCP SDU is delivered to upper layers in ascending order of COUNT, and RX_DELIV is updated to point to the first PDCP SDU which has not been delivered to upper layers.

[0055] D1. If the timer t-Reordering is running and RX_DELIV >= RX_REORD, t-Reordering is stopped.

[0056] E1. If the timer t-Reordering is not running and RX_DELIV < RX_NEXT, RX_REORD=RX_NEXT is updated, and t-Reordering is started.

[0057] In case of t-Reordering timeout, the reception of the packet with COUNT = RX_NEXT and COUNT = RX_REORD is considered as failed, and the following operations are performed:

[0058] A2. The PDCP SDUs with COUNT < RX_REORD and which have completed the downlink reception processing are delivered to upper layers in ascending order.

[0059] B2. The PDCP SDUs with COUNT >= RX_REORD and which have completed the downlink reception processing are delivered to upper layers in ascending order if the COUNTs are consecutive.

[0060] C2. Update RX_DELIV to point to the first PDCP SDU which has not been delivered to upper layers.

[0061] D2. If RX_DELIV < RX_NEXT, update RX_REORD = RX_NEXT, and start t-Reordering.

[0062] 4. Other terms

[0063] The terms "first", "second", and the like in the present application are used to distinguish similar objects, and are not used to describe a particular order or sequence. It should be understood that the terms used in this way can be interchanged under appropriate circumstances, so that the embodiments of the present application can be implemented in an order other than that illustrated or described herein, and the objects distinguished by "first", "second" are usually a class, not limited to the number of objects, for example, the first object can be one or more. In addition, "or" in the present application means at least one of the connected objects. For example, the protection scope of "A or B" at least covers three schemes, namely, scheme one: including A and not including B; scheme two: including B and not including A; scheme three: including A and B. In addition, the terms "A and / or B", "at least one of A and B", "at least one of A or B" also at least cover the above three schemes, respectively. The character " / " generally represents that the objects before and after are in a "or" relationship.

[0064] The term "indicate" in the present application can be a direct indication (or explicit indication) or an indirect indication (or implicit indication). Among them, the direct indication can be understood as that the sender explicitly informs the receiver of the specific information, the operation to be performed or the request result in the sent indication; the indirect indication can be understood as that the receiver determines the corresponding information according to the indication sent by the sender, or judges and determines the operation to be performed or the request result according to the judgment result.

[0065] It is worth noting that the technology described in the embodiments of the present application is not limited to Long Term Evolution (LTE) / LTE-Advanced (LTE-A) systems, but can also be used in other wireless communication systems, such as Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Orthogonal Frequency Division Multiple Access (OFDMA), Single-carrier Frequency-Division Multiple Access (SC-FDMA) or other systems. The terms "system" and "network" in the embodiments of the present application are often used interchangeably, and the described technology can be used in the above-mentioned systems and radio technologies, as well as in other systems and radio technologies. The following description describes a New Radio (NR) system for example purposes, and NR terminology is used in most of the following description, but these technologies can also be applied to systems other than NR systems, such as 6th Generation (6G) communication systems. th

[0066] ​FIG. 2 shows a block diagram of a wireless communication system to which embodiments of the present application can be applied. The wireless communication system includes a terminal 11 and a network-side device 12. The terminal 11 can be a terminal-side device such as a mobile phone, a Tablet Personal Computer, a Laptop Computer, a notebook computer, a Personal Digital Assistant (PDA), a palmtop computer, a netbook, an Ultra-mobile Personal Computer (UMPC), a Mobile Internet Device (MID), an Augmented Reality (AR) device, a Virtual Reality (VR) device, a robot, a wearable device, a flight vehicle, a Vehicle User Equipment (VUE), a shipboard device, a Pedestrian User Equipment (PUE), a smart home (a home device with a wireless communication function such as a refrigerator, a television, a washing machine, or furniture), a game console, a Personal Computer (PC), a kiosk, or a self-service machine. The wearable device includes a smart watch, a smart bracelet, a smart earphone, smart glasses, smart jewelry (a smart bracelet, a smart necklace, a smart ring, a smart necklace, a smart anklet, a smart necklace, etc.), a smart wristband, smart clothes, etc. The vehicle-mounted device can also be referred to as a vehicle-mounted terminal, a vehicle-mounted controller, a vehicle-mounted module, a vehicle-mounted component, a vehicle-mounted chip, or a vehicle-mounted unit, etc. It should be noted that the specific type of the terminal 11 is not limited in the embodiments of the present application. The network-side device 12 can include an access network device or a core network device. The access network device can also be referred to as a Radio Access Network (RAN) device, a radio access network function, or a radio access network unit. The access network device can include a base station, a Wireless Local Area Network (WLAN) Access Point (AP), or a Wireless Fidelity (WiFi) node, etc.The base station can be referred to as a Node B (NB), an evolved Node B (eNB), a next generation Node B (gNB), a New Radio Node B (NR Node B), an access point, a relay station (RBS), a serving base station (SBS), a base transceiver station (BTS), a radio base station, a radio transceiver, a basic service set (BSS), an extended service set (ESS), a home Node B (HNB), a home evolved Node B, a transmit / receive point (TRP), or some other suitable terminology in the art, so long as 5 the base station is capable of achieving the same technical effects, and the base station is not limited to a specific technical term. It should be noted that in the embodiments of the present application, only the base station in the NR system is taken as an example for introduction, and the specific type of the base station is not limited.

[0067] The data transmission method, device, terminal, network side equipment and readable storage medium provided by the embodiments of the present application will be described in detail below in combination with the drawings and some embodiments and application scenarios.

[0068] The data transmission method provided by the embodiments of the present application can be applied to the scenario in which the terminal performs cell switching.

[0069] In one scenario, the terminal performs cell switching in the process of data transmission with the network side device, and the source cell and the target cell are in the same CU, at this time, since the PDCP position is unchanged, therefore, the key can not be changed in the process of switching. In the related art, assuming that the receiving end is the terminal, the terminal is configured to deliver in order, and the COUNT value of the last PDCP data PDU received by the terminal in the source cell is 5, and the PDCP data PDU corresponding to the COUNT value of 6 is not successfully received in the source cell due to the terminal performing cell switching, the COUNT value of the first downlink PDCP data PDU received by the terminal in the target cell is 7 (since the COUNT value of 6 has been used up, the network side device can only start sending data from COUNT = 7 in the target cell). At this time, since the terminal will judge RX_DELIV < RX_NEXT when receiving the downlink PDCP data PDU with the COUNT value of 7, the terminal will start t-Reordering. And since the PDCP data PDU with the COUNT value of 6 fails to be received due to the terminal performing cell switching (i.e. switching from the source cell to the target cell), therefore, the terminal may deliver the PDCP SDU corresponding to the PDCP data PDU with the COUNT value less than or equal to 7 to the upper layer only in the case that t-Reordering times out. Thus, the transmission delay of the PDCP SDU corresponding to the downlink PDCP data PDU with the COUNT value of 7 is large.

[0070] However, in the embodiment of the present application, in the case that the terminal is handed over from the source cell to the target cell, the PDCP entity of the terminal can receive indication information from the network side device, the indication information being used to indicate the related information of the first PDCP PDU of the bearer corresponding to the PDCP entity sent by the network side device in the target cell, so that the PDCP entity can learn whether the first PDCP PDU is received according to the related information, and in the case that the first PDCP PDU is received, the PDCP entity can directly submit at least one PDCP SDU corresponding to the PDCP data PDU with the COUNT value greater than or equal to 7 to the upper layer. It can be understood that, since the PDCP entity can accurately learn the first PDCP PDU according to the related information of the first PDCP PDU indicated by the network side device, and directly submit at least one PDCP SDU corresponding to the PDCP data PDU with the COUNT value less than or equal to 7 to the upper layer in the case that the first PDCP PDU is received without waiting for t-Reordering timeout, the time required for submitting at least one PDCP SDU corresponding to the PDCP data PDU with the COUNT value less than or equal to 7 to the upper layer can be reduced, so that the transmission delay of at least one PDCP SDU corresponding to the PDCP data PDU with the COUNT value less than or equal to 7 can be reduced, and thus the transmission delay of data can be reduced.

[0071] It should be noted that the foregoing is described by taking the terminal as the receiving end and the network side device as the sending end, and in actual application, the terminal can also be the sending end and the network side device can also be the receiving end, which is not described herein again in the embodiment of the present application.

[0072] The execution subject of the data transmission method provided by the embodiment of the present application can be a data transmission device, or a terminal, or a functional module or entity in the terminal, or a functional module or entity in the network side device. The data transmission method is described by taking the first protocol layer entity of the receiving end (for example, the terminal or the network side device) as an example in the embodiment of the present application.

[0073] FIG. 3 shows a flowchart of a data transmission method provided by an embodiment of the present application. As shown in FIG. 3, the data transmission method provided by the embodiment of the present application can include the following steps 101 and 102.

[0074] In step 101, in the case that the terminal is handed over from the first cell to the second cell, the first protocol layer entity of the receiving end receives indication information from the sending end.

[0075] In the embodiments of the present application, the receiving end is a terminal, and the sending end is a network side device corresponding to the second cell; or the sending end is a terminal, and the receiving end is a network side device corresponding to the second cell.

[0076] In some examples, the network side device corresponding to the second cell can be an access network device (for example, a base station) corresponding to the second cell.

[0077] It can be understood that, since the embodiments of the present application stipulate that the receiving end is a terminal and the sending end is a network side device corresponding to the second cell, in subsequent steps, the first protocol layer entity of the terminal can accurately receive the indication information sent by the network side device corresponding to the second cell, and accurately submit at least one SDU to the upper layer in the case that the first protocol layer entity receives the first PDU sent by the network side device corresponding to the second cell on the first bearer of the second cell, so that the transmission delay of downlink transmission can be reduced. Alternatively, since the embodiments of the present application stipulate that the receiving end is a network side device corresponding to the second cell and the sending end is a terminal, in subsequent steps, the first protocol layer entity of the network side device can accurately receive the indication information sent by the terminal, and accurately submit at least one SDU to the upper layer in the case that the first protocol layer entity receives the first PDU sent by the terminal on the first bearer of the second cell, so that the transmission delay of uplink transmission can be reduced.

[0078] In some embodiments of the present application, the first protocol layer entity can be a PDCP entity. Of course, the first protocol layer entity can also be other protocol entities, which are not limited in the embodiments of the present application.

[0079] In the embodiments of the present application, the first cell and the second cell are in the same CU, and the switching of the terminal from the first cell to the second cell is intra-CU switching.

[0080] In some embodiments of the present application, the first cell can be a cell in which the terminal resides. The first cell can be a primary cell or a primary secondary cell of the terminal.

[0081] It can be understood that the process of switching the terminal from the first cell to the second cell can be understood as cell switching or primary secondary cell change. The cell switching can be initiated by the terminal or the network side device, and the primary secondary cell change can be initiated by the terminal or the network side device. The cell switching and the primary secondary cell change do not perform key change.

[0082] In some embodiments of the present application, the first key is the same as the second key; the first key is used for encrypting or integrity protecting data between the terminal and the first cell; and the second key is used for encrypting or integrity protecting data between the terminal and the second cell.

[0083] The first cell can be understood as a source cell, and the second cell can be understood as a target cell.

[0084] In the embodiments of the present application, the indication information is used to indicate the related information of a first protocol data unit (PDU) of a first bearer sent by the sending end in the second cell, and the first bearer is a bearer corresponding to the first protocol layer entity.

[0085] The first PDU can be a PDU that has been sent by the sending end in the second cell or a PDU to be sent.

[0086] In some embodiments of the present application, the first PDU can be specifically a PDCP data PDU.

[0087] In some embodiments of the present application, the first bearer can include at least one of the following: an unacknowledged mode (UM) data radio bearer (DRB), and a signaling radio bearer (SRB).

[0088] In some embodiments of the present application, the indication information is carried by at least one of the following:

[0089] a control PDU;

[0090] a first bit in a data PDU.

[0091] In some embodiments of the present application, the first protocol layer entity can receive the control PDU after the terminal completes the handover or after the configuration of the second cell is applied.

[0092] In some embodiments of the present application, the first bit can be specifically a reserved bit. Of course, the first bit can also be other bits, which are not limited in the embodiments of the present application.

[0093] In some embodiments of the present application, the receiving order of the control PDU and the data PDU is not limited in the embodiments of the present application, and can be selected by those skilled in the art according to requirements.

[0094] As can be seen, since the specific information of the bearer indication information is specified in the embodiments of the present application, the first protocol layer entity can accurately receive the indication information according to the specific information, so that it can be ensured that the first protocol layer entity can accurately know whether the first PDU is received.

[0095] In some embodiments of the present application, the indication information is used to indicate at least one of the following:

[0096] a first count value of the first PDU;

[0097] the first sequence number of the first PDU;

[0098] whether the PDU carrying the indication information is the first PDU.

[0099] In some embodiments of the present application, the first count value can be a PDCP COUNT value.

[0100] In some embodiments of the present application, the first sequence number can also be a PDCP Sequence Number (SN) value.

[0101] In some embodiments of the present application, in the case where the indication information is carried by the first bit in the data PDU, the indication information is used to indicate whether the data PDU carrying the indication information is the first PDU; wherein, in the case where the first bit takes a first value, the indication information is used to indicate that the data PDU is the first PDU; or, in the case where the first bit takes a second value, the indication information is used to indicate that the data PDU is not the first PDU.

[0102] In an example, the first value can be 0 and the second value can be 1; or, the first value can be 1 and the second value can be 0. Of course, the first value and the second value can also be other different values, which are not limited in the embodiments of the present application.

[0103] As such, since the embodiments of the present application specify the specific content indicated by the indication information in the case where the first bit takes different values, the receiving end can accurately indicate the specific content indicated by the indication information according to the specific content and the specific value of the first bit.

[0104] In summary, since the embodiments of the present application specify the specific content indicated by the indication information, the terminal can accurately obtain the specific content and accurately obtain whether the first PDU is received according to the specific content.

[0105] In some embodiments of the present application, the first protocol layer entity can receive the indication information from the second protocol layer entity of the sending end. Wherein, the second protocol layer entity and the first protocol layer entity can be the same or different.

[0106] For example, the first protocol layer entity is a PDCP entity and the second protocol layer entity is also a PDCP entity, i.e., the second protocol layer entity and the first protocol layer entity are the same.

[0107] Step 102, in the case where the first protocol layer entity has received the first PDU, the first protocol layer entity submits at least one first Service Data Unit (SDU) to a higher layer.

[0108] In some embodiments of the present application, the at least one SDU is obtained by the first protocol layer entity from the at least one PDU received by the first protocol layer entity. The at least one SDU can be continuous SDUs or discontinuous SDUs.

[0109] In the present application, the continuous SDUs can be understood as that the count values of the corresponding PDUs are continuous. The discontinuous SDUs can be understood as that the count values of the corresponding PDUs are discontinuous.

[0110] In some embodiments of the present application, the first protocol layer entity has received the first PDU, and the first protocol layer entity has received the first PDU in at least one of the following conditions:

[0111] The count value of the PDU received by the first protocol layer entity matches the first count value;

[0112] The sequence number of the PDU received by the first protocol layer entity matches the first sequence number;

[0113] The first bit of the data PDU received by the first protocol layer entity has the first value; and the indication information indicates that the data PDU is the first PDU when the first bit has the first value.

[0114] Therefore, the first protocol layer entity can accurately determine whether the first PDU has been received according to the conditions.

[0115] In the present application, each of the at least one first SDU is an SDU corresponding to a PDU received by the first protocol layer entity.

[0116] In some embodiments of the present application, the at least one first SDU can include an SDU obtained by the first protocol layer entity from the first PDU.

[0117] In some embodiments of the present application, as shown in FIG. 4, the step 102 can be implemented by the following step 102a in combination with FIG. 3.

[0118] In the step 102a, when the first protocol layer entity has received the first PDU and the value of the first state variable is less than the first count value of the first PDU, the first protocol layer entity sequentially submits the at least one first SDU to the upper layer according to the count values of the PDUs corresponding to the at least one first SDU.

[0119] In the present application, the value of the first state variable indicates the count value of the PDU corresponding to the first SDU waiting to be submitted to the upper layer.

[0120] It should be noted that the "waiting for submitting to the upper layer" can be understood as: not yet submitted to the upper layer but waiting for submitting.

[0121] In some embodiments of the present application, the first status variable can be RX_DELIV.

[0122] In some embodiments of the present application, the first protocol layer entity can submit the at least one first SDU to the upper layer in the order of the count value of the PDU corresponding to the at least one first SDU from small to large. Alternatively, the first protocol layer entity can submit the at least one first SDU to the upper layer in the order of the count value of the PDU corresponding to the at least one first SDU from large to small. Of course, the first protocol layer entity can also submit the at least one first SDU to the upper layer in other orders, which are not limited in the embodiments of the present application.

[0123] As can be seen, since the embodiments of the present application specify the specific way in which the first protocol layer entity submits the at least one first SDU to the upper layer, the first protocol layer entity can submit the at least one first SDU to the upper layer in the specific way in the case that the first PDU has been received.

[0124] The embodiments of the present application provide a data transmission method. In the case that a terminal is switched from a first cell to a second cell, a first protocol layer entity of a receiving end receives information indicating a first PDU of a first bearer transmitted by a sending end in the second cell, the first bearer being a bearer corresponding to the first protocol layer entity, and submits at least one SDU corresponding to the received PDU to an upper layer in the case that the first PDU has been received. In the case that the receiving end is the terminal, the sending end is a network side device corresponding to the second cell. In the case that the sending end is the terminal, the receiving end is a network side device corresponding to the second cell. Since the first protocol layer entity can obtain the information indicating the first PDU of the first bearer transmitted by the sending end in the second cell through the indication information in the case that the terminal is switched from the first cell to the second cell, the first protocol layer entity can directly submit the at least one SDU (i.e. the processed SDU) corresponding to the received PDU to the upper layer in the case that the first PDU has been received without waiting for t-Reordering timeout in the case that some PDCP data PDUs are not received due to the switching of the terminal from the first cell to the second cell. Therefore, the time for submitting the processed SDU to the upper layer can be reduced, and the transmission delay of the SDU can be reduced. Thus, the transmission delay of data can be reduced.

[0125] Of course, the first protocol layer entity can also perform other steps in the case that the first PDU has been received, which will be illustrated below.

[0126] In some embodiments of the present application, the data transmission method provided by the embodiments of the present application can further include at least one of the following steps 201 to 204.

[0127] Step 201, in the case that the first protocol layer entity has received the first PDU, if the first timer is running, the first protocol layer entity determines that the first timer is expired.

[0128] In the embodiments of the present application, the first timer is used to determine the duration that the first protocol layer entity does not receive the PDU.

[0129] It can be understood that the first timer can be t-Reordering in particular, and when the first protocol layer entity determines that it does not receive a certain PDU, the first timer can be started, so that the duration that the first protocol layer entity does not receive the certain PDU can be determined through the first timer.

[0130] In the embodiments of the present application, if the first PDU has been received, it can be considered that the PDU triggering the first timer to run can fail to be received due to the cell switching of the terminal, therefore, the first protocol layer entity can directly determine that the first timer is expired, and subsequent processing can be performed according to the expiration of the first timer, so as to avoid the case that other PDUs cannot trigger the first timer to run.

[0131] It can be known in this way that since in the case that the first protocol layer entity has received the first PDU, that is, in the case that the PDU triggering the first timer to run can fail to be received due to the cell switching of the terminal, the first protocol layer entity can directly determine that the first timer is expired, without waiting for the expiration of the first timer, therefore, the PDU failing to be received due to the cell switching can be avoided, so as to reduce the transmission delay of the data of the target cell.

[0132] Step 202, in the case that the first protocol layer entity has received the first PDU, the first protocol layer entity updates the value of the first state variable to a first numerical value.

[0133] In the embodiments of the present application, the value of the first state variable is used to indicate the count value of the PDU corresponding to the first SDU waiting to be submitted to the upper layer, and the first numerical value is equal to the count value of the PDU corresponding to the second SDU, the second SDU being the first SDU waiting to be submitted to the upper layer, and the indication information including the first count value.

[0134] Thus, in the case that the first protocol layer entity has received the first PDU, the first protocol layer entity can directly update the value of the first state variable to the first value, i.e., the value of the first state variable indicates the correct count value, so that the case that the first protocol layer entity learns the first SDU waiting to be submitted to the upper layer is inaccurate due to the value of the first state variable indicating the incorrect count value can be avoided.

[0135] In the case that the first protocol layer entity has received the first PDU, if the first timer is running and the value of the first state variable is greater than or equal to the value of the second state variable, the first protocol layer entity stops and resets the first timer.

[0136] In the embodiments of the present application, the first timer is used to determine the duration that the first protocol layer entity does not receive the PDU.

[0137] In the embodiments of the present application, the value of the first state variable is used to indicate the count value of the PDU corresponding to the first SDU waiting to be submitted to the upper layer, and the value of the second state variable is used to indicate the count value of the next PDU of the PDU triggering the start of the first timer.

[0138] In some embodiments of the present application, the second state variable can be specifically RX_REORD.

[0139] In the embodiments of the present application, if the first PDU has been received and the value of the first state variable is greater than or equal to the value of the second state variable, it can be considered that the PDU triggering the running of the first timer can fail to be received due to the cell switching of the terminal, so that the first protocol layer entity can stop and reset the first timer.

[0140] Thus, in the case that the first protocol layer entity has received the first PDU, i.e., in the case that the PDU triggering the running of the first timer can fail to be received due to the cell switching of the terminal, the first protocol layer entity can directly stop and reset the first timer without waiting for the first timer to expire, so that the PDU failing to be received due to the cell switching can be avoided, thereby reducing the transmission delay of the data of the target cell.

[0141] In the case that the first protocol layer entity has received the first PDU, if the first timer is not running and the value of the first state variable is less than the value of the third state variable, the first protocol layer entity updates the value of the third state variable to the value of the second state variable and starts the first timer.

[0142] In the embodiments of the present application, the first timer is used to determine the duration that the first protocol layer entity does not receive the PDU.

[0143] In the embodiments of the present application, the value of the first status variable is used to indicate the count value of the PDU corresponding to the first SDU waiting to be submitted to the upper layer; the value of the second status variable is used to indicate the count value of the next PDU of the PDU triggering the starting of the first timer; and the value of the third status variable is used to indicate the count value of the next PDU expected to be received by the first protocol layer entity.

[0144] In some embodiments of the present application, the third status variable can be RX_NEXT.

[0145] In some embodiments of the present application, the first protocol layer entity can determine the value of the third status variable as the value of the second status variable.

[0146] In the embodiments of the present application, if the first PDU has been received and the value of the first status variable is less than the value of the third status variable, it can be considered that there is a PDU not received, and therefore, the first protocol layer entity can update the value of the third status variable as the value of the second status variable, so as to determine the count value of the next PDU expected to be received by the first protocol layer entity as the count value of the next PDU of the PDU triggering the starting of the first timer.

[0147] As can be seen, since the count value of the next PDU expected to be received by the first protocol layer entity can be accurately determined as the count value of the next PDU of the PDU triggering the starting of the first timer in the case that the first timer is not running and the value of the first status variable is less than the value of the third status variable, i.e., in the case that there is a PDU not received, the case that the count value of the next PDU of the PDU triggering the starting of the first timer cannot be determined can be avoided.

[0148] The specific flow of the data transmission method provided by the embodiments of the present application will be illustrated by two complete examples.

[0149] Example 1: the indication information is carried by the control PDU

[0150] The data transmission method provided by the embodiments of the present application can include the following steps:

[0151] Step 11: the terminal performs cell switching or primary secondary cell change, for example, the terminal switches from a first cell to a second cell, and the first key corresponding to the first cell and the second key corresponding to the second cell are the same.

[0152] Step 12, a first protocol layer entity (e.g. PDCP entity) of a receiving end (e.g. terminal) receives a control PDU in a second cell, the control PDU carrying indication information indicating relevant information (e.g. first COUNT value and / or first sequence number, etc.) of a first PDU of a first bearer which has been or will be sent by a sending end (e.g. network side device corresponding to the second cell) in the second cell.

[0153] Step 13, the PDCP entity of the terminal can deliver at least one SDU to a higher layer in ascending order of COUNT (which can not be continuous) in case that the first PDU is received.

[0154] Step 14, the PDCP entity of the terminal can further perform at least one of the following in case that the first PDU is received.

[0155] If the first timer (e.g. t-Reordering) is running, it is determined that the first timer expires, and subsequent processing is performed according to the expiration of the first timer;

[0156] The value of the first state variable (e.g. RX_DELIV) is updated to a first numerical value;

[0157] If the first timer (e.g. t-Reordering) is running and the value of the first state variable (e.g. RX_DELIV) is greater than or equal to the value of the second state variable (e.g. RX_REORD), the first timer (e.g. t-Reordering) is stopped and reset;

[0158] If the first timer (e.g. t-Reordering) is not running and the value of the first state variable (e.g. RX_DELIV) is less than the value of the third state variable (e.g. RX_NEXT), the value of the third state variable (e.g. RX_NEXT) is updated to the value of the second state variable (e.g. RX_REORD), and the first timer (e.g. t-Reordering) is started.

[0159] The following examples are as follows:

[0160] The COUNT value of the last PDU received by the PDCP entity of the terminal in the source cell (i.e. first cell) is 5, and the PDU with COUNT value 6 is not successfully received in the source cell (i.e. first cell); at this time, RX_NEXT = RX_DELIV = 6;

[0161] The PDCP entity of the terminal receives a PDU with PDCP COUNT = 7, at this time, RX_NEXT is updated to 8, t-Reordering is started, and RX_REORD = 7;

[0162] The PDCP entity of the terminal receives a control PDU in the target cell (i.e., the second cell), indicating that the COUNT value associated with the first downlink PDU sent by the second cell is 7;

[0163] The PDCP entity of the terminal determines that the t-Reordering is immediately timed out, and performs the action in the existing protocol after the timeout; and / or, the terminal submits the SDU corresponding to the PDCP COUNT = 7 (i.e., at least one SDU in the above embodiment) to the upper layer, updates the RX_DELIV to COUNT = 8, stops and resets the t-Reordering.

[0164] Example II, the indication information is carried by the first bit of the data PDU

[0165] Step 21, the terminal performs cell switching or primary secondary cell change, for example, the terminal switches from the first cell to the second cell, and the first key corresponding to the first cell and the second key corresponding to the second cell are the same.

[0166] Step 22, the first protocol layer entity (e.g., the PDCP entity) of the receiving end (e.g., the terminal) receives a data PDU in the second cell, and the reserved bit (e.g., the first bit in the above embodiment) of the data PDU carries indication information, which is used to indicate whether the data PDU is the first PDU of the first bearer sent or to be sent by the sending end (e.g., the network side device corresponding to the second cell) in the second cell, or the indication information is used to indicate the first sequence number SN of the first PDU of the first bearer sent or to be sent by the sending end (e.g., the network side device corresponding to the second cell) in the second cell.

[0167] For example, FIG. 5A shows a schematic diagram of a data PDU, which can be a data PDU of an SRB. As shown in FIG. 5, the data PDU includes N octets, for example, octets Oct 1- Oct N. Among them, the reserved bit (e.g., the first bit) includes: the 5th-8th bits in the first Oct 1 and the 8 bits in the second Oct 2, and the 5th-8th bits in the first Oct 1 and the 8 bits in the second Oct 2 carry the SN of the first PDU of the first bearer sent or to be sent by the sending end (e.g., the network side device corresponding to the second cell) in the second cell.

[0168] For example, FIG. 5B shows a schematic diagram of another data PDU. As shown in FIG. 5B, the data PDU includes N octets, such as octets Oct 1-Oct N. The reserved bits (e.g., the first bits) include the 5th bit-8th bit in the first Oct 1 and the 8 bits in the second Oct 2, which carry the SN of the first PDU of the first bearer that has been or will be sent by the sending end (e.g., the network side device corresponding to the second cell) in the second cell.

[0169] For example, FIG. 5C shows a schematic diagram of another data PDU, which can be a data PDU of a DRB. As shown in FIG. 5C, the data PDU includes N octets, such as octets Oct 1-Oct N. The reserved bits (e.g., the first bits) include the 7th bit-8th bit in the first Oct 1, the 8 bits in the second Oct 2, and the 8 bits in the third Oct 3, which carry the SN of the first PDU of the first bearer that has been or will be sent by the sending end (e.g., the network side device corresponding to the second cell) in the second cell.

[0170] It should be noted that in the above FIGS. 5A-5C, each small square is used to represent a bit.

[0171] Step 23, in a case where the first PDU is received, the PDCP entity of the terminal can deliver at least one SDU to the upper layer in ascending order of COUNT (which can not be continuous).

[0172] Step 24, in a case where the first PDU is received, the PDCP entity of the terminal can further perform at least one of the following:

[0173] determining that the first timer (e.g., t-Reordering) is running, and determining that the first timer expires;

[0174] updating the value of the first state variable (e.g., RX_DELIV) to a first numerical value;

[0175] determining that the first timer (e.g., t-Reordering) is running, and determining that the value of the first state variable (e.g., RX_DELIV) is greater than or equal to the value of the second state variable (e.g., RX_REORD), and stopping and resetting the first timer (e.g., t-Reordering);

[0176] If the first timer (e.g., t-Reordering) is not running and the value of the first state variable (e.g., RX_DELIV) is less than the value of the third state variable (e.g., RX_NEXT), then the value of the third state variable (e.g., RX_NEXT) is updated to the value of the second state variable (e.g., RX_REORD) and the first timer (e.g., t-Reordering) is started.

[0177] In summary, the scheme provided by the embodiments of the present application can solve the problem that the data packets transmitted by the second cell cannot be delivered to the upper layer in time due to the SN gap caused by the data interruption in the case of cell switching and no key change.

[0178] The data transmission method provided by the embodiments of the present application can be executed by a data transmission device. In the embodiments of the present application, the data transmission method executed by the data transmission device is taken as an example to illustrate the data transmission device provided by the embodiments of the present application.

[0179] The data transmission device provided by the embodiments of the present application can be a communication device or a component in the communication device, for example, a chip. The communication device can be a terminal, a network side device or a server, etc. Exemplarily, the terminal can include but is not limited to the types of the terminal 11 listed above, the network side device can include but is not limited to the types of the network side device 12 listed above, and the embodiments of the present application are not limited specifically.

[0180] The data transmission apparatus comprises a receiving module, a sending module and a processing module. The receiving module, the sending module and the processing module can be implemented by software or hardware. When implemented by hardware, the processing module can be implemented by a processor, which can include a general-purpose processor, a special-purpose processor, a central processing unit (CPU), a microprocessor, a digital signal processor (DSP), an artificial intelligent (AI) processor, a graphics processing unit (GPU), an application specific integrated circuit (ASIC), a network processor (NP), a field programmable gate array (FPGA) or other programmable logic devices, a gate circuit, a transistor, a discrete hardware component, etc. The receiving module and the sending module can be implemented by a communication interface, which can include a transceiver, a pin, a circuit, a bus, a radio frequency unit, etc.

[0181] Specifically, referring to FIG. 6, when the data transmission apparatus is a terminal or a component in the terminal, the data transmission apparatus 40 comprises a receiving module 41 and a processing module 42.

[0182] The receiving module 41 is configured to receive, in a case where the terminal is handed over from a first cell to a second cell, indication information from a sending end, the indication information being used for indicating related information of a first PDU of a first bearer sent by the sending end in the second cell, the first bearer being a bearer corresponding to the data transmission apparatus 40. The processing module 42 is configured to submit at least one first SDU to a higher layer in a case where the data transmission apparatus 40 has received the first PDU, the first SDU being an SDU corresponding to the received PDU. In a case where the receiving end is a terminal, the sending end is a network side device corresponding to the second cell. In a case where the sending end is a terminal, the receiving end is a network side device corresponding to the second cell.

[0183] The embodiment of the present application provides a data transmission device. In the case that a terminal is switched from a first cell to a second cell, the data transmission device can obtain the related information of a first PDU of a first bearer transmitted by a sending terminal in the second cell through indication information. In the case that some PDCP data PDUs are not received due to the switching of the terminal from the first cell to the second cell, the data transmission device can directly submit at least one SDU (i.e. a processed SDU) corresponding to the received PDU to a high layer in the case that the first PDU is received, without waiting for t-Reordering timeout. Therefore, the waiting time required for submitting the processed SDU to the high layer can be reduced, so that the transmission delay of the SDU can be reduced. In this way, the transmission delay of data can be improved.

[0184] In a possible implementation, the indication information is carried by at least one of the following: a control PDU; a first bit in a data PDU.

[0185] In a possible implementation, the indication information is used to indicate at least one of the following: a first count value of the first PDU; a first sequence number of the first PDU; whether the PDU carrying the indication information is the first PDU.

[0186] In a possible implementation, in the case that the indication information is carried by the first bit in the data PDU, the indication information is used to indicate whether the data PDU carrying the indication information is the first PDU; wherein in the case that the value of the first bit is a first value, the indication information is used to indicate that the data PDU is the first PDU; or in the case that the value of the first bit is a second value, the indication information is used to indicate that the data PDU is not the first PDU.

[0187] In a possible implementation, the data transmission device 40 has received the first PDU satisfies at least one of the following: the count value of the PDU received by the data transmission device 40 matches the first count value; the sequence number of the PDU received by the data transmission device 40 matches the first sequence number; the value of the first bit of the data PDU received by the data transmission device 40 is the first value; in the case that the value of the first bit is the first value, the indication information is used to indicate that the data PDU is the first PDU.

[0188] In a possible implementation, the processing module 42 is specifically used to sequentially submit at least one first SDU to the high layer according to the count value of the PDU corresponding to the at least one first SDU in the case that the value of the first state variable is less than the first count value of the first PDU; wherein the value of the first state variable is used to indicate the count value of the PDU corresponding to the first SDU to be submitted to the high layer.

[0189] In a possible implementation, the processing module 42 is further configured to perform at least one of the following: determining that the first timer expires, if the first timer is running, when the first PDU is received by the data transmission device 40; updating a value of the first state variable to a first numerical value when the first PDU is received by the data transmission device 40; stopping and resetting the first timer, if the first timer is running and the value of the first state variable is greater than or equal to a value of the second state variable, when the first PDU is received by the data transmission device 40; updating the value of the third state variable to the value of the second state variable and starting the first timer, if the first timer is not running and the value of the first state variable is less than a value of the third state variable, when the first PDU is received by the data transmission device 40; wherein the first timer is configured to determine a duration that the data transmission device 40 does not receive the PDU; the value of the first state variable is configured to indicate a count value of the PDU corresponding to a first SDU waiting to be submitted to the upper layer; the first numerical value is equal to a count value of a PDU corresponding to a second SDU, the second SDU being a first SDU waiting to be submitted to the upper layer and indicating information including a first count value of the first PDU, and the value of the second state variable is configured to indicate a count value of a next PDU of the PDU triggering the starting of the first timer; and the value of the third state variable is configured to indicate a count value of a next PDU expected to be received by the data transmission device 40.

[0190] In a possible implementation, the first key is the same as the second key; and the first key is used for encryption or integrity protection of data between the terminal and the first cell; and the second key is used for encryption or integrity protection of data between the terminal and the second cell.

[0191] The data transmission device provided by the embodiments of the present application can implement each process of the method embodiments of FIG. 2 to FIG. 5, and achieve the same technical effects. To avoid repetition, details are not described herein.

[0192] As shown in FIG. 7, the embodiments of the present application further provide a communication device 50, which includes a processor 51 and a memory 52, and the memory 52 stores programs or instructions executable on the processor 51. For example, when the communication device 50 is a terminal, the programs or instructions are executed by the processor 51 to implement each step of the above data transmission method embodiments, and achieve the same technical effects. When the communication device 50 is a network side device, the programs or instructions are executed by the processor 51 to implement each step of the above data transmission method embodiments, and achieve the same technical effects. To avoid repetition, details are not described herein.

[0193] The embodiment of the present application further provides a terminal comprising a processor and a communication interface, wherein the communication interface is coupled with the processor, and the processor is configured to run programs or instructions to implement the steps in the method embodiments shown in FIG. 2 to FIG. 5. The terminal embodiment corresponds to the terminal-side method embodiments described above, and each implementation process and implementation manner of the method embodiments can be applied to the terminal embodiment, and the same technical effects can be achieved. The terminal can be the data transmission device shown in FIG. 6. Specifically, FIG. 8 is a schematic diagram of the hardware structure of a terminal for implementing the embodiment of the present application.

[0194] The terminal 600 includes, but is not limited to, at least part of the components such as a radio frequency unit 601, a network module 602, an audio output unit 603, an input unit 604, a sensor 605, a display unit 606, a user input unit 607, an interface unit 608, a memory 609, and a processor 610.

[0195] Those skilled in the art can understand that the terminal 600 can further include a power supply (such as a battery) for supplying power to each component, and the power supply can be logically connected with the processor 610 through a power management system, so as to realize the functions of power management, such as charging, discharging, and power consumption management, through the power management system. The terminal structure shown in FIG. 8 does not constitute a limitation on the terminal, and the terminal can include more or fewer components than those shown, or combine certain components, or have a different component arrangement, which will not be described here.

[0196] It should be understood that in the embodiment of the present application, the input unit 604 can include a graphics processor 6041 and a microphone 6042, and the graphics processor 6041 processes image data of a still picture or a video obtained by an image capture device (such as a camera) in a video capture mode or an image capture mode. The display unit 606 can include a display panel 6061, which can be configured in the form of a liquid crystal display, an organic light-emitting diode, etc. The user input unit 607 includes at least one of a touch panel 6071 and other input devices 6072. The touch panel 6071 is also called a touch screen. The touch panel 6071 can include two parts of a touch detection device and a touch controller. The other input devices 6072 can include, but are not limited to, a physical keyboard, function keys (such as volume control keys, on-off keys, etc.), a trackball, a mouse, a joystick, etc., which will not be described here.

[0197] In the embodiment of the present application, the radio frequency unit 601 can transmit the downlink data received from the network side device to the processor 610 for processing, and can send uplink data to the network side device. Generally, the radio frequency unit 601 includes, but is not limited to, an antenna, an amplifier, a transceiver, a coupler, a low-noise amplifier, a duplexer, etc.

[0198] The memory 609 can be used to store software programs or instructions and various data. The memory 609 can mainly include a first storage area storing programs or instructions and a second storage area storing data, wherein the first storage area can store an operating system, application programs or instructions required by at least one function (such as a sound playing function, an image playing function, etc.), and the like. In addition, the memory 609 can include a volatile memory or a non-volatile memory. The non-volatile memory can be a Read-Only Memory (ROM), a Programmable ROM (PROM), an Erasable PROM (EPROM), an Electrically EPROM (EEPROM), or a flash memory. The volatile memory can be a Random Access Memory (RAM), a Static RAM (SRAM), a Dynamic RAM (DRAM), a Synchronous DRAM (SDRAM), a Double Data Rate SDRAM (DDR SDRAM), an Enhanced SDRAM (ESDRAM), a Synch link DRAM (SLDRAM), and a Direct Rambus RAM (DRRAM). The memory 609 in the embodiments of the present application includes but is not limited to these and any other suitable types of memory.

[0199] The processor 610 can include one or more processing units; optionally, the processor 610 integrates an application processor and a modem processor, wherein the application processor mainly processes operations related to an operating system, a user interface, and an application program, and the modem processor mainly processes wireless communication signals, such as a baseband processor. It can be understood that the above-mentioned modem processor can also not be integrated into the processor 610.

[0200] The radio frequency unit 601 is configured to, in a case where the terminal is handed over from the first cell to the second cell, receive indication information from the sending end, the indication information being used to indicate related information of a first PDU of a first bearer sent by the sending end in the second cell, the first bearer being a bearer corresponding to a first protocol layer entity of the terminal.

[0201] The processor 610 is configured to submit at least one first SDU corresponding to the received PDU to a higher layer in a case that the first PDU has been received.

[0202] The sending end is a network side device corresponding to the second cell.

[0203] The terminal provided by the embodiments of the present application can learn the related information of the first PDU of the first bearer sent by the sending end in the second cell through the indication information in a case that the terminal is switched from the first cell to the second cell. Thus, in a case that the terminal receives the first PDU at the first protocol layer entity in a case that some PDCP data PDUs are not received due to the terminal being switched from the first cell to the second cell, the terminal can directly submit at least one SDU (i.e., the processed SDU) corresponding to the received PDU to the higher layer without waiting for the t-Reordering timeout. Therefore, the time required for submitting the processed SDU to the higher layer can be reduced, and thus the transmission delay of the SDU can be reduced. As a result, the transmission delay of data can be improved.

[0204] In some embodiments of the present application, the processor 610 is specifically configured to sequentially submit at least one first SDU to a higher layer according to the count value of the PDU corresponding to the at least one first SDU in a case that the value of the first state variable is less than the first count value of the first PDU.

[0205] The value of the first state variable is used to indicate the count value of the PDU corresponding to the first SDU waiting to be submitted to the higher layer.

[0206] In some embodiments of the present application, the processor 610 is further configured to perform at least one of the following: determining that the first timer is timed out in a case that the first PDU has been received and the first timer is running; updating the value of the first state variable to a first numerical value in a case that the first PDU has been received; stopping and resetting the first timer in a case that the first PDU has been received, the first timer is running, and the value of the first state variable is greater than or equal to the value of the second state variable; and updating the value of the third state variable to the value of the second state variable and starting the first timer in a case that the first PDU has been received, the first timer is not running, and the value of the first state variable is less than the value of the third state variable.

[0207] The first timer is used to determine a time length during which a PDU is not received; a value of the first state variable is used to indicate a count value of a PDU corresponding to a first SDU waiting for submission to a higher layer; the first value is equal to a count value of a PDU corresponding to a second SDU, the second SDU being a first SDU waiting for submission to the higher layer and corresponding to a PDU with a count value greater than the first count value of the first PDU, and the indication information includes the first count value; a value of the second state variable is used to indicate a count value of a next PDU of the PDU triggering the start of the first timer; and a value of the third state variable is used to indicate a count value of a next PDU expected to be received.

[0208] It can be understood that the implementation processes of the implementation manners mentioned in the embodiments can refer to the related descriptions of the method embodiments and achieve the same or corresponding technical effects. To avoid repetition, details are not described herein again.

[0209] The embodiments of the present application further provide a network side device, which comprises a processor and a communication interface. The communication interface is coupled to the processor. The processor is configured to run programs or instructions to implement the steps of the method embodiments shown in FIGS. 2 to 5. The network side device embodiments correspond to the network side device method embodiments. The implementation processes and implementation manners of the method embodiments can be applied to the network side device embodiments and achieve the same technical effects.

[0210] Specifically, the embodiments of the present application further provide a network side device, which can be the data transmission apparatus shown in FIG. 6. As shown in FIG. 9, the network side device 700 comprises an antenna 701, a radio frequency device 702, a baseband device 703, a processor 704 and a memory 705. The antenna 701 is connected to the radio frequency device 702. In the uplink direction, the radio frequency device 702 receives information through the antenna 701 and sends the received information to the baseband device 703 for processing. In the downlink direction, the baseband device 703 processes the information to be sent and sends it to the radio frequency device 702. The radio frequency device 702 processes the received information and sends it out through the antenna 701.

[0211] The method performed by the network side device in the above embodiments can be implemented in the baseband device 703, which comprises a baseband processor.

[0212] The baseband device 703 may, for example, comprise at least one baseband board, which is provided with a plurality of chips, as shown in FIG. 9. One of the chips is, for example, a baseband processor, which is connected to the memory 705 through a bus interface to call programs in the memory 705 and perform the network device operations shown in the above method embodiments.

[0213] The network-side device can further include a network interface 706, for example, a Common Public Radio Interface (CPRI).

[0214] Specifically, the network-side device 700 of the embodiments of the present application further includes instructions or programs stored on the memory 705 and executable on the processor 704, the processor 704 invokes the instructions or programs in the memory 705 to perform the method performed by the modules shown in FIG. 6 and achieve the same technical effects. To avoid repetition, details are not described herein.

[0215] The embodiments of the present application also provide a readable storage medium, the readable storage medium stores programs or instructions, the programs or instructions are executed by a processor to implement various processes of the above-mentioned data transmission method embodiments and achieve the same technical effects. To avoid repetition, details are not described herein.

[0216] The processor is the processor in the terminal in the above-mentioned embodiments. The readable storage medium includes a computer readable storage medium, such as a computer readable only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, etc. In some examples, the readable storage medium can be a non-transitory readable storage medium.

[0217] The embodiments of the present application further provide a chip, the chip includes a processor and a communication interface, the communication interface and the processor are coupled, the processor is used to run programs or instructions to implement various processes of the above-mentioned data transmission method embodiments and achieve the same technical effects. To avoid repetition, details are not described herein.

[0218] It should be understood that the chip mentioned in the embodiments of the present application can also be referred to as a system chip, a system chip, a chip system or a system on chip, etc.

[0219] The embodiments of the present application further provide a computer program / program product, the computer program / program product is stored in a storage medium, the computer program / program product is executed by at least one processor to implement various processes of the above-mentioned data transmission method embodiments and achieve the same technical effects. To avoid repetition, details are not described herein.

[0220] It should be noted that, in the present document, the terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can also include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by "comprises a", "comprising", or the like does not, without more constraints, preclude the existence of additional identical elements in the process, method, article, or apparatus that comprises the element. Furthermore, it is to be understood that the methods and apparatuses of the present application can be carried out by specific hardware, software, or a combination thereof, and that the scope of the application is not limited to the specific order of execution of the steps described in the examples. In addition, features described in relation to certain examples can be combined in other examples.

[0221] From the above description of the embodiments, it is clear that the above-mentioned method can be realized by means of a computer software product and a general hardware platform, of course, it can also be realized by hardware. The computer software product is stored in a storage medium (such as ROM, RAM, magnetic disc, optical disc, etc.), and includes a plurality of instructions for making the terminal or network side device execute the method described in each embodiment of the present application.

[0222] The embodiments of the present application are described above in combination with the drawings, but the present application is not limited to the above-mentioned specific embodiments, the above-mentioned specific embodiments are only illustrative, not restrictive, and those skilled in the art can make many forms of embodiments under the inspiration of the present application without departing from the scope of the present application and the scope protected by the claims.

Claims

1. A data transmission method, comprising: in a case that a terminal is handed over from a first cell to a second cell, a first protocol layer entity of a receiving end receiving indication information from a sending end, the indication information being used to indicate related information of a first protocol data unit (PDU) of a first bearer sent by the sending end in the second cell, the first bearer being a bearer corresponding to the first protocol layer entity; in a case that the first protocol layer entity has received the first PDU, the first protocol layer entity submitting at least one first service data unit (SDU) to a higher layer, the first SDU being an SDU corresponding to the received PDU; wherein, in a case that the receiving end is the terminal, the sending end is a network side device corresponding to the second cell; or, in a case that the sending end is the terminal, the receiving end is the network side device corresponding to the second cell.

2. The method of claim 1, wherein, the indication information is carried by at least one of the following: a control PDU; a first bit in a data PDU.

3. The method of claim 2, wherein, the indication information is used to indicate at least one of the following: a first count value of the first PDU; a first sequence number of the first PDU; whether the PDU carrying the indication information is the first PDU.

4. The method of claim 3, wherein, in a case that the indication information is carried by the first bit in the data PDU, the indication information is used to indicate whether the data PDU carrying the indication information is the first PDU; wherein, in a case that a value of the first bit is a first value, the indication information is used to indicate that the data PDU is the first PDU; or, in a case that the value of the first bit is a second value, the indication information is used to indicate that the data PDU is not the first PDU.

5. The method of any one of claims 2 to 4, wherein, the first protocol layer entity having received the first PDU satisfies at least one of the following: a count value of a PDU received by the first protocol layer entity matches the first count value; a sequence number of the PDU received by the first protocol layer entity matches the first sequence number; a value of the first bit in the data PDU received by the first protocol layer entity is the first value, and in a case that the value of the first bit is the first value, the indication information is used to indicate that the data PDU is the first PDU.

6. The method of any one of claims 1 to 5, wherein, the first protocol layer entity submitting at least one first SDU to a higher layer, comprising: in a case that a value of a first state variable is less than a first count value of the first PDU, the first protocol layer entity submitting at least one first SDU to the higher layer in sequence according to a count value of a PDU corresponding to the first SDU; wherein, the value of the first state variable is used to indicate a count value of a PDU corresponding to a first SDU waiting to be submitted to the higher layer.

7. The method of any one of claims 1 to 6, wherein, the method further comprises at least one of the following: in a case that the first protocol layer entity has received the first PDU, determining that a first timer is expired if the first timer is running; in a case that the first protocol layer entity has received the first PDU, updating a value of a first state variable to a first numerical value; if the first timer is running and the value of the first status variable is greater than or equal to the value of the second status variable, then stopping and resetting the first timer, in the case that the first protocol layer entity has received the first PDU; if the first timer is not running and the value of the first status variable is less than the value of the third status variable, then updating the value of the third status variable to the value of the second status variable and starting the first timer, in the case that the first protocol layer entity has received the first PDU; wherein the value of the first status variable is used to indicate a count value of a first PDU corresponding to a first SDU waiting to be submitted to an upper layer, the first count value being equal to a count value of a PDU corresponding to a second SDU, the second SDU being a first SDU waiting to be submitted to an upper layer and having a count value of a corresponding PDU greater than the first count value of the first PDU, the indication information comprising the first count value; the value of the second status variable is used to indicate a count value of a next PDU of the PDU triggering the starting of the first timer; the value of the third status variable is used to indicate a count value of a next PDU expected to be received by the first protocol layer entity.

8. The method of any one of claims 1 to 7, wherein, the first key is the same as the second key; wherein the first key is used for encryption or integrity protection of data between the terminal and the first cell, and the second key is used for encryption or integrity protection of data between the terminal and the second cell.

9. A data transmission apparatus, the data transmission apparatus comprising: a receiving module and a processing module; the receiving module is configured to receive indication information from a sending end in the case that a terminal is handed over from a first cell to a second cell, the receiving end or the sending end being the terminal, the indication information being used to indicate related information of a first PDU of a first bearer transmitted by the sending end in the second cell, the first bearer being a bearer corresponding to the data transmission apparatus; the processing module is configured to submit at least one first SDU to an upper layer in the case that the data transmission apparatus has received the first PDU, the first SDU being an SDU corresponding to the received PDU; wherein, in the case that the receiving end is the terminal, the sending end is a network side device corresponding to the second cell; or, in the case that the sending end is the terminal, the receiving end is a network side device corresponding to the second cell.

10. The apparatus of claim 9, wherein, the indication information is carried by at least one of the following: a control PDU; a first bit in a data PDU.

11. The apparatus of claim 10, wherein, the indication information is used to indicate at least one of the following: a first count value of the first PDU; a first sequence number of the first PDU; whether the PDU carrying the indication information is the first PDU.

12. The apparatus of claim 11, wherein, in the case that the indication information is carried by the first bit in the data PDU, the indication information is used to indicate whether the data PDU carrying the indication information is the first PDU; wherein, in the case that the first bit has a first value, the indication information is used to indicate that the data PDU is the first PDU; or, In a case that the first bit has a second value, the indication information indicates that the data PDU is not the first PDU.

13. The apparatus of any one of claims 10-12, wherein, The data transmission device has received the first PDU satisfies at least one of the following conditions: The count value of the PDU received by the data transmission device matches the first count value; The sequence number of the PDU received by the data transmission device matches the first sequence number; The first bit of the data PDU received by the data transmission device has a first value; in a case that the first bit has the first value, the indication information indicates that the data PDU is the first PDU.

14. The apparatus of any one of claims 9-13, wherein, The processing module is specifically configured to, in a case that the value of the first state variable is less than the first count value of the first PDU, sequentially submit at least one first SDU to the upper layer according to the count value of the PDU corresponding to the at least one first SDU. The value of the first state variable is used to indicate the count value of the PDU corresponding to the first SDU waiting to be submitted to the upper layer.

15. The apparatus of any one of claims 9 to 14, wherein, The processing module is further configured to perform at least one of the following: In a case that the data transmission device has received the first PDU, if the first timer is running, it is determined that the first timer is timed out; In a case that the data transmission device has received the first PDU, the value of the first state variable is updated to a first numerical value; In a case that the data transmission device has received the first PDU, if the first timer is running and the value of the first state variable is greater than or equal to the value of the second state variable, the first timer is stopped and reset; In a case that the data transmission device has received the first PDU, if the first timer is not running and the value of the first state variable is less than the value of the third state variable, the value of the third state variable is updated to the value of the second state variable, and the first timer is started; The value of the first state variable is used to indicate the count value of the PDU corresponding to the first SDU waiting to be submitted to the upper layer; the first numerical value is equal to the count value of the PDU corresponding to the second SDU, the second SDU is the first SDU waiting to be submitted to the upper layer and the count value of the corresponding PDU is greater than the first count value of the first PDU, and the indication information includes the first count value; The value of the second state variable is used to indicate the count value of the next PDU of the PDU triggering the starting of the first timer; The value of the third state variable is used to indicate the count value of the next PDU expected to be received by the data transmission device.

16. The apparatus of any one of claims 9 to 15, wherein, The first key is the same as the second key; The first key is used for encrypting or integrity protecting data between the terminal and the first cell; and the second key is used for encrypting or integrity protecting data between the terminal and the second cell. 17.A terminal, comprising a processor and a memory, the memory storing programs or instructions executable on the processor, the programs or instructions, when executed by the processor, implement steps of the data transmission method according to any one of claims 1 to 8. 18.A network side device, comprising a processor and a memory, the memory storing programs or instructions executable on the processor, the programs or instructions, when executed by the processor, implement steps of the data transmission method according to any one of claims 1 to 8. 19.A readable storage medium, the readable storage medium storing programs or instructions, the programs or instructions, when executed by a processor, implement steps of the data transmission method according to any one of claims 1 to 8.

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