CN113475120B

CN113475120B - Data transmission method and device during cell switching

Info

Publication number: CN113475120B
Application number: CN201980093056.7A
Authority: CN
Inventors: 尤心
Original assignee: Guangdong Oppo Mobile Telecommunications Corp Ltd
Current assignee: Guangdong Oppo Mobile Telecommunications Corp Ltd
Priority date: 2019-08-23
Filing date: 2019-08-23
Publication date: 2023-10-03
Anticipated expiration: 2039-08-23
Also published as: CN113475120A; WO2021035445A1

Abstract

The application discloses a data transmission method and device during cell switching. The method comprises the following steps: after receiving a cell switching command, transmitting PDCP PDU of a source cell in the source cell; and after the random access is completed, transmitting the PDCP PDU of the target cell corresponding to the PDCP PDU which is not received by the source base station of the source cell in the target cell. After the random access is finished and the uplink transmission in the source cell is stopped, the PDCP PDU which is not confirmed by the source base station of the source cell is transmitted in the target cell, so that the data is not lost in the cell switching process, and the technical problem that the data of the terminal is lost because the PDCP PDU which is not transmitted or is transmitted but not confirmed by the source base station cannot be continuously transmitted when the uplink transmission in the source cell is stopped is solved.

Description

Data transmission method and device during cell switching

Technical Field

The present application relates to the field of communications technologies, and in particular, to a method and an apparatus for transmitting data during cell handover.

Background

Cell switching refers to channel switching that is required in order to maintain uninterrupted communication for a mobile user when the mobile station moves from one cell (referred to as a base station or coverage area of a base station) to another cell in a wireless communication system. The existing cell switching technology is performed through random access, when a UE (User Equipment) needs to switch from a source cell to a target cell, data can be simultaneously transmitted to the source cell and the target cell through PDCP (Packet Data Convergence Protocol ), and after the random access is finished, the UE stops data transmission in the source cell.

However, in the conventional cell switching method, when the uplink transmission in the source cell is stopped, PDCP PDUs which are not transmitted or transmitted but not acknowledged by the source base station cannot be continuously transmitted, and thus there is a technical problem that the terminal data is lost.

Disclosure of Invention

The application provides a data transmission method and a data transmission device during cell switching, which aim to solve the technical problem of data loss of a user terminal during cell switching.

In a first aspect, a specific embodiment of the present application provides a data transmission method during cell handover, including:

after receiving the cell switching command, transmitting PDCP PDU of the source cell in the source cell;

after the random access is completed, transmitting PDCP PDU of the target cell corresponding to PDCP PDU which is not received by the source base station of the source cell in the target cell.

In a second aspect, a specific embodiment of the present application provides a data transmission apparatus during cell handover, including:

the configuration module is used for generating PDCP PDU of the source cell from PDCP SDU according to the PDCP configuration of the source cell after receiving the cell switching command;

a transmission module for transmitting PDCP PDU of the source cell in the source cell after receiving the cell switching command, and

and transmitting the PDCP PDU of the target cell corresponding to the PDCP PDU which is not received by the source base station of the source cell in the target cell after the random access is completed.

In a third aspect, a specific embodiment of the present application provides a terminal device, including: and the processor is used for storing an uplink control channel transmission program which can be run on the processor, and realizing the data transmission method during any cell switching when the processor executes the uplink control channel transmission program.

In a fourth aspect, embodiments of the present application provide a computer-readable storage medium storing a computer program for electronic data exchange, where the computer program causes a computer to execute any one of the above-described data transmission methods at the time of cell handover.

In a fifth aspect, embodiments of the present application provide a computer program product comprising a non-transitory computer readable storage medium storing a computer program operable to cause a computer to perform a method of data transmission at any one of the above cell handovers.

In a sixth aspect, embodiments of the present application provide a chip, including: and a processor for calling and running the computer program from the memory, so that the device installed with the chip executes any one of the data transmission methods during cell switching.

In a seventh aspect, a specific embodiment of the present application provides a computer program, where the computer program causes a computer to execute any one of the above-mentioned data transmission methods at the time of cell handover.

The technical scheme provided by the specific embodiment of the application can comprise the following beneficial effects:

after receiving the cell switching command, transmitting PDCP PDU of the source cell in the source cell; after the random access is completed, transmitting PDCP PDU of the target cell corresponding to PDCP PDU which is not received by the source base station of the source cell in the target cell. After the random access is completed and the uplink transmission in the source cell is stopped, the user terminal transmits the PDCP PDU which is not confirmed by the source base station of the source cell in the target cell, thereby ensuring that the data can not be lost in the cell switching process, and solving the technical problem that the data of the terminal is lost because the PDCP PDU which is not transmitted or is transmitted but not confirmed by the source base station can not be continuously transmitted when the uplink transmission in the source cell is stopped.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the application as claimed.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the application and together with the description, serve to explain the principles of the application.

FIG. 1 is a network architecture diagram of a communication system to which embodiments of the present application may be applied;

fig. 2 is a flowchart of a data transmission method at the time of cell handover according to an embodiment of the present application;

fig. 3 is a flowchart of a data transmission method at the time of a cell handover according to an embodiment of the present application;

fig. 4 is a flowchart of a data transmission method at the time of cell handover according to another embodiment of the present application;

fig. 5 is a block diagram of an apparatus for implementing a data transmission method at the time of a cell handover according to various embodiments of the present disclosure;

fig. 6 is a schematic hardware configuration diagram of a terminal device for implementing a data transmission method at the time of cell handover according to various embodiments of the present disclosure.

Detailed Description

Reference will now be made in detail to exemplary embodiments, examples of which are illustrated in the accompanying drawings. When the following description refers to the accompanying drawings, the same numbers in different drawings refer to the same or similar elements, unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the embodiments of the application. Rather, they are merely examples of methods and apparatus consistent with aspects of the application as detailed in the accompanying claims. All other embodiments, which are obtained by persons skilled in the art without making any inventive effort, are within the scope of the present application based on the embodiments of the present application.

Fig. 1 is a system architecture of a communication system to which the following embodiments of the present application may be applied. The system architecture comprises: source base station A, target base station B, user terminal C.

When the ue C moves from the source bs a (the range covered by the source bs a is the source cell a in the present application) to the target bs B (the range covered by the source bs B is the source cell B in the present application), in order to keep the ue C from interrupting the communication, a channel switch is required. Current channel switching techniques are performed by random access. After receiving the cell handover command from the source base station a, the user terminal C may transmit data to both the source base station a and the target base station B through PDCP (Packet Data Convergence Protocol ) before the random access procedure with the target base station B is completed. After the random access is finished, the user terminal C stops the data transmission in the source base station a.

However, the inventors have found that since the PDCP layer of the user terminal C does not know when the random access procedure can end, the PDCP layer may continue header compression and ciphering with the security key of the source cell a and transmit the ciphered PDCP PDU (Protocol Data Unit ) to the RLC (Radio Link Control, radio link layer control protocol) layer. Therefore, when the random access procedure is ended, the user terminal C may still have PDCP PDUs encrypted by the source cell key that are not transmitted or that have been transmitted but not acknowledged by the source base station a, and when the uplink transmission in the source base station a is stopped, the PDCP PDUs that have not been transmitted or that have not acknowledged by the source base station a cannot be continuously transmitted, so that a loss phenomenon occurs in the data transmitted by the user terminal C to the source base station a in the cell handover procedure.

The following detailed description of the present application will describe in detail how to ensure that data transmitted from the ue C to the source bs a is not lost during cell handover.

In the present system architecture, the example communication system may be a global system for mobile communications (Global System for Mobile communications, GSM), a code division multiple Access (Code Division Multiple Access, CDMA) system, a time division multiple Access (Time Division Multiple Access, TDMA) system, a wideband code division multiple Access (Wideband Code Division Multiple Access Wireless, WCDMA), a frequency division multiple Access (Frequency Division Multiple Addressing, FDMA) system, an orthogonal frequency division multiple Access (Orthogonal Frequency-Division Multiple Access, OFDMA) system, a single carrier FDMA (SC-FDMA) system, a general packet Radio service (General Packet Radio Service, GPRS) system, an LTE (Long Term Evolution ) system, a 5G (5 th-Generation, fifth Generation mobile communication technology) NR (NR Radio Access) system, and other such communication systems. The example communication system specifically includes a network side device and a terminal, when the terminal accesses a mobile communication network provided by the network side device, the terminal and the network side device may be in communication connection through a wireless link, where the communication connection manner may be a single connection manner or a dual connection manner or a multiple connection manner, but when the communication connection manner is a single connection manner, the network side device may be an LTE base station or an NR base station (also referred to as a gNB base station), and when the communication manner is a dual connection manner (specifically, may be implemented by a carrier aggregation CA technology, or implemented by multiple network side devices), and when the terminal connects multiple network side devices, the multiple network side devices may be a master base station MCG and an auxiliary base station SCG, and data backhaul is performed between the base stations through a backhaul link, where the master base station may be an LTE base station, the auxiliary base station may be an LTE base station, or the master base station may be an NR base station. The receiving-side RLC entity described in the embodiments of the present application may be a terminal or software (e.g., a protocol stack) and/or hardware (e.g., a modem) in the terminal, and likewise, the transmitting-side RLC entity may be a network-side device or software (e.g., a protocol stack) and/or hardware (e.g., a modem) in the network-side device.

In the present embodiment, the terms "network" and "system" are often used interchangeably, as those skilled in the art will understand the meaning.

The User terminal according to the embodiments of the present application may include various handheld devices, vehicle mounted devices, wearable devices, computing devices or other processing devices connected to a wireless modem, and various forms of User Equipment (UE), mobile Station (MS), terminal devices (terminal devices), etc. For convenience of description, the above-mentioned devices are collectively referred to as a terminal.

In addition, the terms "system" and "network" are often used interchangeably herein. Herein, a text

The term "and/or" is merely an association relationship describing an associated object, and means that three relationships may exist, for example, a and/or B may represent: a exists alone, A and B exist together, and B exists alone. In addition, the character "/" herein generally indicates that the front and rear associated objects are an "or" relationship.

It should be understood that in embodiments of the present application, "B corresponding to a" means that B is associated with a, from which B may be determined. It should also be understood that determining B from a does not mean determining B from a alone, but may also determine B from a and/or other information.

Fig. 2 is a flowchart of a data transmission method at the time of cell handover according to an embodiment of the present application. As shown in fig. 2, the data transmission method at the time of cell handover is applied to a user terminal, and may include the steps of:

in step 110, after receiving the cell handover command, PDCP PDUs of the source cell are transmitted in the source cell.

Among them, in the 3GPP (3 rd Generation Partnership Project, third generation partnership project) mobility enhancement problem, including LTE and NR (new Radio Access), an optimization method for reducing the interruption time at the time of handover is proposed. The first mode is as follows: during switching, the target base station is added as an SN (auxiliary node), then the SN (namely the target base station) is changed into an MN (main node) through role change signaling, and finally the source base station is released, so that the effect of reducing the interruption time during switching is achieved. The second mode is as follows: based on the existing handover procedure, when the UE receives the HO command (Hand Over command ), the UE continues to maintain connection with the source base station, and initiates random access to the target base station, and the connection with the source base station is released until the UE completes access with the target base station.

Similar to the LTE system, the NR system supports a handover procedure of a UE in a connected state. When a user using a network service moves from one cell to another cell, or due to radio transmission traffic load adjustment, active operation maintenance, equipment failure, etc., the system transfers the communication link between the user and the source cell to the new cell, i.e., performs a handover procedure, in order to ensure continuity of communication and quality of service.

Taking an Xn interface switching process as an example, the whole switching process is divided into the following three phases:

(1) Switching preparation: including measurement control and reporting, handover requests, and acknowledgements. The handover confirmation message contains the cell handover command generated by the target cell, and the source cell does not allow any modification to the cell handover command generated by the target cell, and directly forwards the cell handover command to the UE.

(2) The switching is performed: the UE immediately performs a handover procedure after receiving the cell handover command, i.e., the UE disconnects the source cell and connects with the target cell, for example, performs random access, sends an RRC (Radio Resource Control ) handover complete message to the target base station, etc., SN state transition, data forwarding.

(3) And (3) switching is completed: the target cell performs Path Switch with AMF (Access and Mobility Management Function, access and mobility management entity) and UPF (User Port Function, user port), releasing the UE context of the source base station.

In the existing ebb (Enhanced Mobile Broadband ) handover procedure, random access is applied, and the random access procedure includes:

msg1 (first message): the UE transmits a random access preamble.

Msg2 (second message): the target base station transmits a random access response message.

Msg3 (third message): the UE sends an RRC connection request.

Msg4 (fourth message): the UE receives RRC connection establishment (this procedure is also referred to as collision resolution procedure).

The UE may transmit data to the target cell in Msg3 while the UE continues to transmit uplink data in the source cell. In order to transmit data in the Msg3, the UE establishes a PDCP entity function (which may be common to the PDCP entity of the source cell) corresponding to the target cell before the Msg3 is transmitted. When the random access procedure is ended, the UE stops uplink data transmission in the source cell. However, since the PDCP layer of the UE does not know when the random access procedure can end, the PDCP layer may continue header compression and ciphering with the security key of the source cell and transmit the ciphered PDCP PDU to the RLC layer. At the end of the random access procedure, the UE side may still have PDCP PDUs ciphered by the source cell key that are not transmitted or transmitted but not acknowledged by the source base station. There is a problem that when the uplink transmission in the source cell is stopped, the PDCP PDU which is not transmitted or transmitted but not acknowledged by the source base station cannot be continuously transmitted, resulting in loss of terminal data.

Therefore, the source base station sends an eMBB cell switching command to the UE through an RRC reconfiguration message, the UE sends Msg1 to the target base station after receiving the cell switching command, and simultaneously generates PDCP PDU of the source cell according to PDCP SDU (Service Data Unit ) of the source cell and transmits the PDCP PDU of the source cell in the source cell.

After receiving the Msg2, the UE may generate PDCP PDUs of the target cell according to the PDCP configuration of the target cell before receiving the Msg4 sent by the target base station, so as to send uplink data to the source base station in the source cell and to the target base station in the target cell at the same time, specifically, send PDCP PDUs generated according to the PDCP configuration of the source cell to the source base station and send PDCP PDUs generated according to the PDCP configuration of the target cell to the target base station. The PDCP PDU of the target cell may be generated not according to the PDCP configuration of the target cell, but only the PDCP PDU generated according to the PDCP configuration of the source cell may be transmitted to the source base station.

In step 150, after the random access is completed, PDCP PDUs of the target cell corresponding to PDCP PDUs not received by the source base station of the source cell are transmitted in the target cell. Wherein the PDCP PDU which does not receive the confirmation of the source base station of the source cell comprises: PDCP PDUs not transmitted in the source cell and/or PDCP PDUs transmitted in the source cell but not acknowledged by the source base station of the source cell.

After receiving the Msg4, the UE indicates conflict resolution, and at this time, it means that random access is completed, and at this time, the PDCP PDU that is not acknowledged by the source base station of the source cell is the PDCP PDU that is not transmitted or is not transmitted, and needs to be retransmitted to the target base station in the target cell, so that, according to the PDCP of the target cell, the PDCP PDU of the target cell corresponding to the PDCP PDU that is not acknowledged by the source base station of the source cell is transmitted in the target cell, thereby ensuring that data will not be lost in the cell switching process.

The specific implementation mode realizes that data cannot be lost in the cell switching process, and solves the technical problem that when uplink transmission in a source cell is stopped, the PDCP PDU which is not transmitted or transmitted but not received by a source base station cannot continue to be transmitted, so that data of a terminal is lost.

Fig. 3 is a flowchart of a data transmission method at the time of cell handover according to an embodiment of the present application. As shown in fig. 3, the method includes:

in step 100, the source base station sends an eMBB cell handover command to the user terminal.

When the user terminal UE needs to be switched from the source cell to the target cell, an ebb cell switching command is sent to the user terminal by the source base station, and the process of switching the user terminal from the source cell to the target cell starts to be executed.

In step 120, after receiving the cell handover command, PDCP SDUs of the PDCP PDUs of the source cell are generated, and PDCP PDUs with the same sequence number are generated according to the PDCP configuration of the target cell.

After receiving a cell switching command, the UE performs operations such as header compression, encryption and the like according to the PDCP configuration of a source cell for the same PDCP SDU and generates a PDCP PDU for transmission of the source cell; and generating PDCP PDU for target cell transmission after performing operations such as header compression, ciphering and the like according to the PDCP configuration of the target cell. The PDCP PDUs used for the source cell transmission use the same sequence number as the PDCP PDUs used for the target cell transmission. The PDCP PDU generated by the method can be immediately used.

In step 130, the user terminal performs random access with the target base station. Wherein, after receiving Msg4, the UE indicates collision resolution, representing completion of random access.

The specific flow of step 150 in the specific implementation corresponding to fig. 2 described above in one embodiment includes step 151 and step 153:

in step 151, a second sequence number is obtained, where the second sequence number is a sequence number of a PDCP PDU that does not receive an acknowledgement from the source base station.

After the UE receives the Msg4, the random access is completed, at this time, the UE stops sending uplink data to the source cell, and performs information interaction with the source base station for PDCP PDUs generated by using PDCP configuration of the source cell, so as to obtain PDCP PDUs from the source base station, which are not acknowledged by the source base station, and obtain sequence numbers of the PDCP PDUs, that is, the second sequence number.

In step 153, among PDCP PDUs generated according to the PDCP configuration of the target cell, PDCP PDUs having the same sequence number as the second sequence number are transmitted in the target cell.

And finding the PDCP PDU with the same sequence number generated by the PDCP configuration of the target cell through the second sequence number of the PDCP PDU which is not received by the source base station, and transmitting and/or retransmitting the PDCP PDU with the same sequence number in the target cell according to the PDCP configuration of the target cell.

In an exemplary embodiment, for the sequence numbers of PDCP PDUs that have been received from the source base station, PDCP PDUs that are identical to those sequence numbers, generated according to the target cell configuration, are released to save buffer space.

In the cell switching process, the specific embodiment generates two PDCP PDUs after performing operations such as header compression, encryption and the like respectively according to the PDCP configuration of the source cell and the PDCP configuration of the target cell aiming at the same PDCP SDU, wherein one PDCP PDU is used for the transmission of the source cell and one PDCP PDU is used for the transmission of the target cell; but the two PDUs use the same SN number. After the random access process of the user terminal and the target cell is finished, knowing which PDCP PDUs are not transmitted in the source cell or transmitted but not confirmed by the source base station, finding corresponding PDCP PDUs for transmitting the target cell according to the sequence numbers of the PDCP PDUs, and retransmitting the PDCP PDUs in the target cell. Because the retransmitted PUCP PDU is already compressed and encrypted in the previous switching process and is buffered in the system, the retransmission can be immediately used. Therefore, the efficiency of retransmitting data in the switching process can be improved.

Fig. 4 is a flowchart of a data transmission method at the time of cell handover according to another embodiment of the present application. As shown in fig. 4, the method further includes:

In step 130, the UE performs a random access procedure with the target base station, and after receiving Msg4, the UE indicates that the collision resolution is performed, which represents that the random access is completed.

Step 150 in the above-described embodiment corresponding to fig. 2 includes step 155, step 157 and step 159 in the specific flow of another example:

in step 155, PDCP SDUs and sequence numbers corresponding to PDCP PDUs not received from the source base station of the source cell are obtained.

After the random access is completed, the UE performs information interaction with the source base station, so that the PDCP PDU and the sequence number corresponding to the PDCP PDU which are not confirmed by the source base station are obtained from the source base station of the source cell, and the PDCP PDU which is not confirmed by the source base station is retransmitted.

In step 157, PDCP SDUs are generated into PDCP PDUs of the target cell with the same sequence number according to the target cell PDCP configuration.

The time point for starting to establish the PDCP protocol layer of the target cell may be: when a cell switching command is received or when an Msg2 message is received; before Msg3 is sent. And the PDCP protocol layer of the source cell of the UE transmits PDCP SDUs and serial numbers corresponding to the PDCP PDUs which are not confirmed by the source base station to the PDCP protocol layer of the target cell. The PDCP protocol layer of the target cell carries out header compression and encryption operation on the PDCP SDUs again, and generates the PDCP SDUs of the target cell with the same sequence number according to the PDCP configuration of the target cell.

In step 159, the PDCP PDU of the target cell is transmitted within the target cell.

The PDCP PDU of the target cell has the advantage of saving buffer space.

In this embodiment, after the random access is completed, the UE stops sending uplink data to the source cell, and for those PDCP PDUs generated using the PDCP configuration of the source cell, if the PDCP PDUs have not been transmitted in the source cell or have been transmitted in the source cell but not received the acknowledgement of the source base station, the PDCP protocol layer of the source cell of the UE transfers PDCP SDUs and SN numbers corresponding to the PDCP PDUs to the PDCP protocol layer of the target cell. The PDCP protocol layer of the target cell carries out header compression and encryption operation on PDCP SDUs corresponding to the SNs again, and PDCP PDUs generated by the PDCP configuration of the target cell are transmitted in the target cell. Therefore, the duplicate data does not need to be cached in the cell switching process, and the cache space is saved.

In one exemplary embodiment, the PDCP PDU that does not receive the source base station acknowledgement of the source cell includes: PDCP PDUs not transmitted in the source cell and/or PDCP PDUs transmitted in the source cell but not acknowledged by the source base station of the source cell.

In one exemplary embodiment, the cell switch command is an eMBB-based cell switch command.

Fig. 5 is a block diagram of an apparatus for implementing a data transmission method at the time of cell handover according to various embodiments of the present disclosure. The apparatus performs all or part of the steps of the data transmission method at the time of cell handover shown in any one of fig. 2, as shown in fig. 5, and includes, but is not limited to: a configuration module 210 and a transmission module 250.

And the configuration module 210 is configured to generate PDCP SDUs into PDCP PDUs of the source cell according to the PDCP configuration of the source cell after receiving the cell handover command.

A transmitting module 250 for transmitting PDCP PDU of the source cell in the source cell after receiving the cell switch command, and

In an exemplary embodiment, the configuration module 210 is further configured to:

after receiving the cell switching command, generating PDCP SDUs of the PDCP PDU of the source cell, and generating PDCP PDUs with the same sequence number according to the PDCP configuration of the target cell.

In an exemplary embodiment, the transmission module 250 is further configured to:

acquiring a second sequence number, wherein the second sequence number is the sequence number of the PDCP PDU which does not receive the confirmation of the source base station, and

and transmitting the PDCP PDU with the sequence number identical to the second sequence number in the PDCP PDU generated according to the PDCP configuration of the target cell in the target cell.

In an exemplary embodiment, the configuration module 210 and the transmission module 250 are further configured to:

the transmission module 250 is configured to obtain PDCP SDUs and sequence numbers corresponding to PDCP PDUs that have not received the acknowledgement from the source base station of the source cell.

The configuration module 210 is configured to generate PDCP PDUs of the target cell with the same sequence number from PDCP SDUs of the target cell according to the PDCP configuration of the target cell.

The transmitting module 250 is further configured to transmit PDCP PDUs of the target cell within the target cell.

The implementation process of the functions and roles of each module in the above device is detailed in the implementation process of the corresponding steps in any data transmission method during cell switching provided in the above specific embodiment, and will not be described herein.

Fig. 6 is a schematic hardware configuration diagram of a terminal device for implementing a data transmission method at the time of cell handover according to various embodiments of the present disclosure. As shown in fig. 6, the terminal device includes: the processor 310, the memory 320 and the above-mentioned components of the terminal device are in communication with each other via a bus system.

The processor 310 may be a single component or may be a combination of processing elements. For example, it may be a CPU, ASIC, or one or more integrated circuits configured to implement the above methods, such as at least one microprocessor DSP, or at least one programmable gate array FPGA, or the like.

The memory 320 stores an uplink control channel transmission program that can be executed by the processor 310, and when the processor 310 executes the uplink control channel transmission program, part or all of the steps of the data transmission method during cell handover in the above-described method embodiment are implemented.

The embodiment of the application also provides a computer readable storage medium, wherein the computer readable storage medium stores a computer program for electronic data exchange, and the computer program causes a computer to execute part or all of the steps of the data transmission method during cell switching in the embodiment of the method.

The present application also provides a computer program product, wherein the computer program product comprises a non-transitory computer readable storage medium storing a computer program operable to cause a computer to perform some or all of the steps of a data transmission method at a cell handover in a method embodiment as described above. The computer program product may be a software installation package.

The specific embodiment of the application also provides a chip, which comprises: and a processor for calling and running the computer program from the memory, so that the device on which the chip is mounted performs part or all of the steps of the data transmission method at the time of cell switching in the above-described method embodiment.

The present application also provides a computer program for causing a computer to execute some or all of the steps of the data transmission method at the time of cell handover in the above-described method embodiment.

The steps of a method or algorithm described in connection with the embodiments disclosed herein may be embodied in hardware, or may be embodied in software instructions executed by a processor. The software instructions may be comprised of corresponding software modules that may be stored in random access Memory (Random Access Memory, RAM), flash Memory, read Only Memory (ROM), erasable programmable Read Only Memory (Erasable Programmable ROM), electrically Erasable Programmable Read Only Memory (EEPROM), registers, hard disk, a removable disk, a compact disc Read Only Memory (CD-ROM), or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor such the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor. The processor and the storage medium may reside in an ASIC. In addition, the ASIC may reside in an access network device, a target network device, or a core network device. It is of course also possible that the processor and the storage medium reside as discrete components in an access network device, a target network device, or a core network device.

Those skilled in the art will appreciate that in one or more of the foregoing examples, the functions described in the detailed description of the application may be implemented, in whole or in part, in software, hardware, firmware, or any combination thereof. When implemented in software, may be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the processes or functions described in the embodiments of the present application are produced in whole or in part. The computer may be a general purpose computer, a special purpose computer, a computer network, or other programmable apparatus. The computer instructions may be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another computer-readable storage medium, for example, the computer instructions may be transmitted from one website, computer, server, or data center to another website, computer, server, or data center by a wired (e.g., coaxial cable, fiber optic, digital subscriber line (Digital Subscriber Line, DSL)) or wireless (e.g., infrared, wireless, microwave, etc.). The computer readable storage medium may be any available medium that can be accessed by a computer or a data storage device such as a server, data center, etc. that contains an integration of one or more available media. The usable medium may be a magnetic medium (e.g., a floppy Disk, a hard Disk, a magnetic tape), an optical medium (e.g., a digital video disc (Digital Video Disc, DVD)), or a semiconductor medium (e.g., a Solid State Disk (SSD)), or the like.

The foregoing embodiments have been provided for the purpose of illustrating the embodiments of the present application in further detail, and it should be understood that the foregoing embodiments are merely illustrative of the embodiments of the present application and are not intended to limit the scope of the embodiments of the present application, and any modifications, equivalents, improvements, etc. made on the basis of the technical solutions of the embodiments of the present application are intended to be included in the scope of the embodiments of the present application.

It is to be understood that the application is not limited to the precise arrangements and instrumentalities shown in the drawings, which have been described above, and that various modifications and changes may be effected without departing from the scope thereof. The scope of the application is limited only by the appended claims.

Claims

1. A data transmission method during cell switching, applied to a terminal device, the method comprising:

after receiving a cell switching command, generating PDCP PDUs for source cell transmission according to a PDCP configuration of a source cell and PDCP PDUs for target cell transmission according to a PDCP configuration of a target cell for the same PDCP SDU, and transmitting the PDCP PDUs for source cell transmission in the source cell, wherein the PDCP PDUs for source cell transmission and the PDCP PDUs for target cell transmission use the same sequence number;

after the random access with the target cell is completed, a second sequence number is obtained from a source base station of the source cell, wherein the second sequence number is a sequence number of a PDCP PDU which is not received by the source base station and is confirmed in the PDCP PDU which is used for the transmission of the source cell;

among PDCP PDUs used for transmission in the target cell, transmitting PDCP PDUs identical to the second sequence number in the target cell, and releasing PDCP PDUs identical to the sequence number of the PDCP PDU that has received the acknowledgement from the source base station.

2. The method of claim 1, wherein the PDCP PDU not received the source base station acknowledgement comprises:

PDCP PDUs not transmitted in the source cell and/or PDCP PDUs transmitted in the source cell but not acknowledged by the source base station of the source cell.

3. The method according to claim 1 or 2, wherein the cell handover command is an eMBB-based cell handover command.

4. A data transmission apparatus at the time of cell handover, the apparatus comprising:

the configuration module is used for generating PDCP PDUs for source cell transmission according to the PDCP configuration of the source cell and PDCP PDUs for target cell transmission according to the PDCP configuration of the target cell for the same PDCP SDU after receiving the cell switching command, wherein the PDCP PDUs for the source cell transmission and the PDCP PDUs for the target cell transmission use the same sequence number;

a transmission module, configured to transmit PDCP PDUs used for transmission by the source cell in the source cell;

the transmission module is further configured to obtain a second sequence number from a source base station of the source cell after completing random access with the target cell, where the second sequence number is a sequence number of a PDCP PDU that is not received by the source base station from PDCP PDUs used for transmission by the source cell;

the transmission module is further configured to transmit, in the target cell, PDCP PDUs identical to the second sequence number among PDCP PDUs used for transmission in the target cell, and release PDCP PDUs having sequence numbers identical to PDCP PDUs that have been acknowledged by the source base station.

5. A terminal device, the terminal device comprising: a processor and a memory, wherein the memory stores an uplink control channel transmission program that can be executed by the processor, and the processor implements the data transmission method at the time of cell handover according to any one of claims 1 to 3 when executing the uplink control channel transmission program.

6. A computer-readable storage medium, characterized in that it stores a computer program for electronic data exchange, wherein the computer program causes a computer to execute the data transmission method at the time of cell handover according to any one of claims 1 to 3.

7. A chip, comprising: a processor for calling and running a computer program from a memory, so that a device on which the chip is mounted performs the data transmission method at the time of cell handover according to any one of claims 1-3.