CN112449348B

CN112449348B - Communication method and communication device

Info

Publication number: CN112449348B
Application number: CN201910770336.9A
Authority: CN
Inventors: 严乐; 曾清海; 耿婷婷
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2019-08-16
Filing date: 2019-08-16
Publication date: 2022-11-18
Anticipated expiration: 2039-08-16
Also published as: CN112449348A

Abstract

The application provides a communication method and a communication device, which can ensure that terminal equipment correctly receives data in the requirement of realizing 0ms time delay in the switching process. The method comprises the following steps: receiving a first message from the first network device or the second network device; receiving a PDCP PDU from the first network device; determining a target parameter for processing the PDCP PDU according to the first message, wherein the target parameter is one of a first parameter corresponding to the first network device and a second parameter corresponding to the second network device, and the first parameter or the second parameter is used for processing the PDCP PDU; and processing the PDCP PDU received from the first network equipment according to the target parameter to obtain the PDCP SDU. The method can be used for a switching scene that the service equipment of the terminal equipment is switched from the second network equipment to the first network equipment.

Description

Communication method and communication device

Technical Field

The present application relates to the field of communications, and more particularly, to a communication method and a communication apparatus in the field of communications.

Background

In a conventional mobile communication system, as a terminal device moves, the terminal device needs to switch from the coverage of a source network device to the coverage of a target network device. In the switching process, after the source network device sends the switching message to the terminal device, data transmission between the terminal device and the source network device is interrupted, until the terminal device is successfully switched to the target network device, the terminal device can perform data transmission with the target network device, and at this time, the data transmission can be recovered.

In order to improve user experience and system performance, the third generation partnership project (3 GPP) proposes a requirement for implementing 0ms delay in the handover process, and how to ensure that the terminal device correctly receives data is an urgent problem to be solved in the requirement for implementing 0ms delay in the handover process.

Disclosure of Invention

The application provides a communication method and a communication device, which can ensure that terminal equipment can correctly receive data in the requirement of realizing 0ms time delay in the switching process.

In a first aspect, a communication method is provided, including: receiving a first message from the first network device or the second network device; receiving a Packet Data Convergence Protocol (PDCP) Protocol Data Unit (PDU) from the first network device; determining a target parameter for processing the PDCP PDU according to the first message, wherein the target parameter is one of a first parameter corresponding to the first network device and a second parameter corresponding to the second network device; the first parameter or the second parameter is used for processing the PDCP PDU; and processing the PDCP PDU received from the first network equipment according to the target parameter to obtain a PDCP Service Data Unit (SDU).

Therefore, in the communication method provided in this embodiment of the present application, in order to implement a 0ms delay, in a handover process, the second network element device needs to send a PDCP PDU to the first network device, and the first network device sends the PDCP PDU from the second network device to the terminal device, so that the PDCP PDU sent to the terminal device by the first network device includes both a PDCP PDU from the second network device and a PDCP DPU obtained through its own processing.

Optionally, the determining, by the terminal device, the target parameter according to the first message may include: and determining the target parameter according to the first indication information in the first message, or determining the target parameter according to whether the first message is received.

In one possible design. The first parameter includes at least one of a key corresponding to the first network device, a header decompression context corresponding to the first network device, and an integrity verification parameter corresponding to the first network device; the second parameter may include at least one of a key corresponding to the second network device, a header decompression context corresponding to the second network device, and an integrity verification parameter corresponding to the second network device.

In one possible design, the second network device is a source network device and the first network device is a target network device.

Specifically, the PDCP PDU received from the first network device may be a PDCP PDU processed by the first network device itself, or a PDCP PDU sent by the second network device and received by the first network device.

In one possible design, determining the target parameter for processing the PDCP PDU according to the first message may be: and determining the target parameter for processing the PDCP PDU according to whether the first message is received, namely if the first message is not received, determining the target parameter as the second parameter, and if the first message is received, determining the target parameter as the first parameter.

In one possible design, the communication method can be applied to a scenario in which the terminal device switches from the second network device to the first network device.

In one possible design, the determining target parameters for processing the PDCP PDU based on the first message includes: and the PDCP PDU received from the first network equipment is sent to the first network equipment by the second network equipment, and the target parameter for processing the PDCP PDU is determined to be the second parameter according to the first message.

In one possible design, the determining target parameters for processing the PDCP PDU based on the first message includes: the PDCP PDU received from the first network device is obtained by the first network device by using a corresponding parameter thereof, and a target parameter for processing the PDCP PDU is determined as the first parameter according to the first message.

In a possible design, the first message includes first indication information of bearer granularity, where the first indication information is used to assist the terminal device in determining the target parameter, that is, each bearer carries respective corresponding first indication information, and first PDCP SNs indicated by different bearers corresponding first indication information may be the same or different.

In one possible design, the first message is a message carrying granularity.

In one possible design, the first indication information includes a last PDCP sequence number for processing a PDCP PDU received from the first network device using a corresponding second parameter of the second network device; or the first indication information is used for indicating the maximum first PDCP sequence number of the PDCP PDUs obtained by using the second parameters corresponding to the second network equipment.

In one possible design, the determining target parameters for processing the PDCP PDU from the first message includes:

if a Packet Data Convergence Protocol (PDCP) sequence number of the PDCP PDU received from the first network equipment is less than or equal to the first PDCP sequence number, the target parameter is the second parameter; and/or the presence of a gas in the gas,

if the PDCP sequence number of the PDCP PDU received from the first network equipment is larger than the first PDCP sequence number, the target parameter is the first parameter.

In one possible design, the first message is used to indicate an end of PDCP PDU sent by the first network device from the second network device, and the determining the target parameter for processing the PDCP PDU according to the first message includes:

before the terminal device receives a first message from the first network device or a second network device, the target parameter is the second parameter;

after the terminal device receives a first message from the first network device or a second network device, the target parameter is the first parameter.

In one possible design, the first message includes a radio resource control RRC message or a PDCP control protocol data unit PDU or a downlink control message DCI or a medium access control MAC control element CE.

In one possible design, after receiving the first message sent by the first network device or the second network device, the method further includes: releasing the RRC connection with the second network device.

In a second aspect, a communication method is provided, including: the first network equipment sends PDCP PDU to the terminal equipment; the first network device sends a first message to the terminal device, where the first message is used to assist the terminal device in determining a target parameter, and the target parameter is used for the terminal device to process a PDCP PDU received from the first network device, where the target parameter is one of a first parameter corresponding to the first network device and a second parameter corresponding to the second network device, and the first parameter or the second parameter is used for the terminal device to process the PDCP PDU.

In one possible design, the first network device is a target network device and the second network device is a source network device.

In one possible design, the communication method can be applied to a scenario in which the terminal device is switched from the second network device to the first network device.

In one possible design, before the first network device sends PDCP PDUs to a terminal device, the method further comprises: the first network device receives the PDCP PDUs from a second network device.

In one possible design, the first message is used to indicate an end of PDCP PDU sent by the first network device from the second network device.

In a possible design, the first network device receives PDCP SDUs sent by the user plane functional network element, and processes the PDCP SDUs by using its corresponding parameters to obtain PDCP PDUs, and sends the PDCP PDUs to the terminal device.

In one possible design, the first network device sends a first message to the terminal device, including: after the first network device sends all the PDCP PDUs from the second network device to the terminal device, the first network device sends the first message to the terminal device. That is, the PDCP PDU sent by the first network device to the terminal device may be the PDCP PDU from the second network device or may be obtained by using its corresponding parameter.

In one possible design, before the first network device sends the first message to the terminal device, the method further includes: and the first network equipment receives a second message from the second network equipment, wherein the second message is used for informing the first network equipment of distributing the PDCP SN for the received PDCP service data units SDU without the distributed PDCP serial number SN.

In a possible design, the first message includes first indication information of bearer granularity, where the first indication information is used for the terminal device to determine the target parameter, and first PDCP SNs indicated by the first indication information corresponding to different bearers may be the same or different.

In one possible design, the first indication information includes a first PDCP sequence number of a last PDCP PDU processed using a second parameter corresponding to the second network device.

In one possible design, the first message may include a radio resource control RRC message or a PDCP control protocol data unit PDU or a downlink control message DCI or a medium access control MAC control element CE.

In a third aspect, a communication method is provided, including: generating, by a second network device, a first message, where the first message is used to assist a terminal device in determining a target parameter, where the target parameter is used for the terminal device to process a PDCP PDU received from the first network device, where the target parameter is one of a first parameter corresponding to the first network device and a second parameter corresponding to the second network device, and the first parameter or the second parameter is used for the terminal device to process the PDCP PDU; and the second network equipment sends a first message to the terminal equipment.

In one possible design, after the second network device sends a radio resource control, RRC, reconfiguration message to the terminal device, the method further includes: the second network device sends the PDCP PDU to the first network device.

In one possible design, the method further includes: and the second network equipment sends a second message to the first network equipment, wherein the second message is used for informing the first network equipment of distributing PDCP SN for the received PDCP service data units SDU without the distributed PDCP sequence numbers SN.

In one possible design, the first message includes first indication information of bearer granularity, where the first indication information is used by the terminal device to determine the target parameter.

In one possible design, the first indication information is used to indicate a first PDCP sequence number of a last PDCP PDU processed using a corresponding second parameter of the second network device.

In a fourth aspect, a communication method is provided, including: a first network device or a second network device sends a first message to a terminal device, the terminal device receives the first message, and the terminal device determines a target parameter according to the first message, wherein the target parameter is one of a first parameter corresponding to the first network device and a second parameter corresponding to the second network device, and the first parameter or the second parameter is used for the terminal device to process the PDCP PDU; the first network equipment sends PDCP PDU to the terminal equipment, and the terminal equipment receives the PDCP PDU from the first network equipment; and the terminal equipment processes the PDCP PDU received from the first network equipment according to the target parameter to obtain the PDCP SDU.

In a fifth aspect, the present application provides a communication device for implementing the method of the first aspect and/or any possible implementation manner thereof. The apparatus may be a terminal device, or may be an apparatus or a component in the terminal device, or may be an apparatus or a component that can be used in cooperation with the terminal device. In one design, the apparatus may include a module which performs one-to-one correspondence of the method/operation/step/action described in the first aspect and/or any possible implementation manner thereof, where the module may be a hardware circuit, a software circuit, or a combination of a hardware circuit and a software circuit. In one design, the apparatus may include a transceiver unit and a processing unit.

In a sixth aspect, the present application provides a communication device for implementing the method of the second aspect and/or any possible implementation manner thereof. The apparatus may be the first network device, an apparatus in the first network device, or an apparatus capable of being used with the first network device. In one design, the apparatus may include a module corresponding to one for performing the method/operation/step/action described in the second aspect and/or any possible implementation manner thereof, and the module may be a hardware circuit, a software circuit, or a combination of a hardware circuit and a software circuit. In one design, the apparatus may include a transceiver unit.

In a seventh aspect, the present application provides a communication device for implementing the method of the third aspect and/or any possible implementation manner thereof. The apparatus may be a second network device, or may be an apparatus or a component in the second network device, or may be an apparatus or a component that can be used with the second network device. In one design, the apparatus may include a module corresponding to one for performing the method/operation/step/action described in the third aspect and/or any possible implementation manner thereof, and the module may be a hardware circuit, a software circuit, or a combination of a hardware circuit and a software circuit. In one design, the apparatus may include a transceiver unit and a processing unit.

In an eighth aspect, the present application provides a communication device comprising a processor configured to implement the method described in the first aspect and/or any possible implementation manner thereof. The apparatus may further comprise a memory coupled to the processor, the processor being configured to implement the method described in the above first aspect and/or any possible implementation thereof. Optionally, the processor is configured to store instructions, and when the processor executes the instructions stored in the memory, the method described in the above first aspect and/or any possible implementation manner thereof may be implemented. The apparatus may also include a communication interface for the apparatus to communicate with other devices, which may be, for example, a transceiver, circuit, bus, module, pin, or other type of communication interface.

In a ninth aspect, the present application provides a communication device comprising a processor for implementing the method described in the second aspect above and/or any possible implementation thereof. The apparatus may further comprise a memory coupled to the processor for implementing the method described in the second aspect above and/or any possible implementation thereof. Optionally, the processor is configured to store instructions, and when the processor executes the instructions stored in the memory, the method described in the second aspect and/or any possible implementation manner thereof may be implemented. The apparatus may also include a communication interface for the apparatus to communicate with other devices.

In a tenth aspect, the present application provides a communication device comprising a processor configured to implement the method described in the third aspect and/or any possible implementation manner thereof. The apparatus may further comprise a memory coupled to the processor, the processor being configured to implement the method described in the third aspect above and/or any possible implementation thereof. Optionally, the processor is configured to store instructions, and when the processor executes the instructions stored in the memory, the method described in the third aspect and/or any possible implementation manner thereof may be implemented. The apparatus may also include a communication interface for the apparatus to communicate with other devices.

In an eleventh aspect, the present application provides a communication system, which includes the apparatus provided in the fifth aspect, the apparatus provided in the sixth aspect, and the apparatus provided in the seventh aspect; or

The system comprises the device provided by the eighth aspect, the device provided by the ninth aspect and the device provided by the tenth aspect;

in a twelfth aspect, the present application provides a computer readable storage medium having stored thereon computer instructions which, when run on a computer, cause the computer to perform the method of the first aspect and any possible design thereof.

In a thirteenth aspect, the present application provides a computer readable storage medium having stored thereon computer instructions which, when run on a computer, cause the computer to perform the method of the second aspect and any possible design thereof.

In a fourteenth aspect, the present application provides a computer readable storage medium having stored thereon computer instructions which, when run on a computer, cause the computer to perform the method of the third aspect and any possible design thereof.

In a fifteenth aspect, the present application provides a computer readable storage medium having stored thereon computer instructions which, when run on a computer, cause the computer to perform the method of the fourth aspect and any possible design thereof.

In a sixteenth aspect, the present application provides a chip comprising a processor. A processor is adapted to perform the method of the first aspect and any possible implementation thereof.

Optionally, the chip further comprises a memory, the memory being coupled to the processor.

Further optionally, the chip further comprises a communication interface.

In a seventeenth aspect, the present application provides a chip comprising a processor. The processor is adapted to perform the method of the second aspect and any possible implementation thereof.

Further optionally, the chip further comprises a communication interface.

In an eighteenth aspect, the present application provides a chip comprising a processor. A processor is adapted to perform the method of the third aspect and any possible implementation thereof.

Further optionally, the chip further comprises a communication interface.

In a nineteenth aspect, the present application provides a chip comprising a processor. The processor is adapted to perform the method of the fourth aspect and any possible implementations thereof.

Further optionally, the chip further comprises a communication interface.

In a twentieth aspect, the present application provides a computer program product comprising computer program code which, when run on a computer, causes the computer to perform the method of the first aspect and any possible design thereof.

In a twenty-first aspect, the present application provides a computer program product comprising computer program code which, when run on a computer, causes the computer to perform the method of the second aspect and any possible implementation thereof.

In a twenty-second aspect, the present application provides a computer program product comprising computer program code which, when run on a computer, causes the computer to perform the method of the third aspect and any possible implementation thereof.

In a twenty-third aspect, the present application provides a computer program product comprising computer program code which, when run on a computer, causes the computer to perform the method of the fourth aspect and any possible implementation thereof.

Drawings

Fig. 1 is an architecture diagram of a communication system according to an embodiment of the present application.

Fig. 2 is a schematic switching diagram provided in an embodiment of the present application.

Fig. 3 is another schematic switching diagram provided in the embodiment of the present application.

Fig. 4 is a schematic diagram of a communication method according to an embodiment of the present application.

Fig. 5 is a schematic diagram of another communication method provided in the embodiment of the present application.

Fig. 6 is a schematic diagram of a protocol stack provided in an embodiment of the present application.

Fig. 7 is a schematic diagram of another protocol stack provided in the embodiment of the present application.

Fig. 8 is a schematic diagram of another communication method provided in the embodiment of the present application.

Fig. 9 is a schematic block diagram of a communication device provided in an embodiment of the present application.

Fig. 10 is a schematic block diagram of a communication device according to another embodiment of the present application.

Fig. 11 is a schematic block diagram of a communication device according to another embodiment of the present application.

Fig. 12 is a schematic block diagram of a communication device according to still another embodiment of the present application.

Detailed Description

The technical solution in the present application will be described below with reference to the accompanying drawings.

The technical solution of the embodiment of the present application may be applied to various communication systems, for example, a Long Term Evolution (LTE) system, an LTE Frequency Division Duplex (FDD) system, an LTE Time Division Duplex (TDD), a Universal Mobile Telecommunications System (UMTS), a Worldwide Interoperability for Microwave Access (WiMAX) communication system, a future fifth generation (5 g) system, a New Radio (NR), or the like.

Terminal equipment in the embodiments of the present application may refer to user equipment, access terminals, subscriber units, subscriber stations, mobile stations, remote terminals, mobile devices, user terminals, wireless communication devices, user agents, or user devices. The terminal device may also be a cellular phone, a cordless phone, a Session Initiation Protocol (SIP) phone, a Wireless Local Loop (WLL) station, a Personal Digital Assistant (PDA), a handheld device with wireless communication function, a computing device or other processing device connected to a wireless modem, a vehicle-mounted device, a wearable device, a terminal device in a future 5G network or a terminal device in a future evolved Public Land Mobile Network (PLMN), and the like, which is not limited in this application.

The network devices (such as the following first network device and second network device) in the embodiments of the present application may be any device having a wireless transceiving function. The network devices include, but are not limited to: an evolved Node B (eNB), a Radio Network Controller (RNC), a Node B (Node B, NB), a Base Station Controller (BSC), a Base Transceiver Station (BTS), a home NodeB (or home Node B, HNB), a Base Band Unit (BBU), an Access Point (AP) in a wireless fidelity (WIFI) system, a wireless relay Node, a wireless backhaul Node, a Transmission Point (TP), or a transmission and reception point (BBU), and the like, and may also be a fifth generation (transmission, 5G) system, for example, a gNB or a Transmission Point (TP) in a new air interface (new NR), or a group of antennas (e.g., a Radio Network Controller (RNC), a Node B (NB), a base transceiver station (BSC), a Base Transceiver Station (BTS), or a Base Transceiver Station (BTS) system, or a group of base transceiver stations (BBU), and a radio relay Node (BTS) or a radio transmission and reception point (BTS) system, and a radio network controller (BTS), or a radio network transceiver station (BTS), or a radio network Node B, NB).

In some deployments, the gNB may include a Centralized Unit (CU) and a Distributed Unit (DU). The gNB may also include an Active Antenna Unit (AAU). The CU implements part of the function of the gNB, and the DU implements part of the function of the gNB. For example, a CU is responsible for handling non-real-time protocols and services, and implementing functions of a Radio Resource Control (RRC) layer and a Packet Data Convergence Protocol (PDCP) layer. The DU is responsible for processing a physical layer protocol and a real-time service, and implements functions of a Radio Link Control (RLC) layer, a Medium Access Control (MAC) layer, and a Physical (PHY) layer. The AAU implements part of the physical layer processing functions, radio frequency processing, and active antenna related functions. Since the information of the RRC layer eventually becomes or is converted from the information of the PHY layer, the higher layer signaling, such as the RRC layer signaling, may also be considered to be transmitted by the DU or transmitted by the DU and the AAU under this architecture.

It will be appreciated that the network device may be a device that includes one or more of a CU, DU, AAU. In addition, the CU may be divided into network devices in an access network (RAN), or may be divided into network devices in a Core Network (CN), which is not limited in this application.

Referring to fig. 1, fig. 1 is an architecture diagram of a communication system suitable for use with embodiments of the present application. As shown in fig. 1, the wireless communication system may include a first network device 110 and a second network device 120, and one or more terminal devices 130. When the terminal device moves from the cell coverage area under the second network device 120 to the cell coverage area under the first network device 110, or due to reasons such as the need to adjust the wireless transmission service load of the cell under the second network device 120, in order to ensure the communication continuity and the service quality, the communication system transfers the communication link between the terminal device and the cell under the second network device 120 to the cell under the first network device 110, that is, the network device served by the terminal device is switched from the second network device 120 to the first network device 110 in fig. 1.

In the following, the first network device 110 is taken as a target base station, the second network device 120 is taken as a source base station, and the terminal device 130 is taken as a UE for example, in a conventional handover process, after the source base station sends a handover message to the UE, data transmission between the UE and the source base station may be interrupted until the UE is successfully handed over to the target base station, and the UE may perform data transmission with the target base station. In the LTE system, the handover message may be a Radio Resource Control (RRC) connection reconfiguration message including a mobility control information (mobility control) cell, and in the NR system, the handover message may be an RRC reconfiguration message including a synchronization reconfiguration (synchronization with sync) cell. Specifically, after the UE successfully accesses the target base station, the UE sends an RRC reconfiguration complete message to the target base station, and at this time, the air interface can resume data transmission. Therefore, there is an interruption delay in the handover process.

In order to improve the user experience, the 3GPP proposes a requirement for realizing 0ms delay in the handover process. To implement 0ms delay in the handover process, the handover process shown in fig. 2 is proposed, and fig. 2 illustrates an NR system as an example. After the source base station sends the handover message to the UE, data forwarding (data forwarding) may be performed between the source base station and the target base station. That is, the source base station forwards a PDCP Service Data Unit (SDU) to which a Packet Data Convergence Protocol (PDCP) Sequence Number (SN) is allocated to the target base station, that is, the source base station sends to the target base station the PDCP SDU(s) and the PDCP SNs corresponding to each PDCP SDU. Wherein, each PDCP SDU forwarded to the target base station respectively corresponds to a PDCP SN which is distributed by the source base station, and each PDCP SDU distributed with the PDCP SN has the PDCP SN corresponding to the PDCP SDU. The PDCP SDUs(s) forwarded to the target base station are subsequently processed by the target base station, for example, using parameters corresponding to the target base station (for example, the parameters may include a header compression context, a security key, or an integrity protection parameter, etc.), and obtaining PDCP PDUs(s) after processing (for example, performing header compression, ciphering, adding a PDCP header, etc.), and sending the PDCP PDUs(s) to the UE. In fig. 2, the UE may receive both PDCP PDUs(s) from the source base station and PDCP PDUs(s) from the target base station before the UE disconnects the RRC connection with the source base station. The UE may process the PDCP PDU(s) received from the source base station using the parameters corresponding to the source base station, and the UE may process the PDCP PDU(s) received from the target base station using the parameters corresponding to the target base station. Therefore, in the handover process, the UE needs to store/maintain at least two sets of parameters (for example, parameters corresponding to the source base station and parameters corresponding to the target base station) for processing data from the source base station and the target base station, so that the complexity of processing data by the UE may be increased in the handover process.

To address the above problem, fig. 3 illustrates an NR system as an example, as shown in fig. 3. The source base station may first allocate PDCP SNs to PDCP SDUs, and then perform subsequent processing using parameters corresponding to the source base station (for example, the parameters may include a header compression context, a security key, or an integrity protection parameter), that is, the source base station performs processing such as header compression, ciphering, and PDCP header addition in addition to allocating PDCP SNs to obtain PDCP PDUs, and forwards the obtained PDCP PDUs to the target base station, that is, the PDCP PDUs(s) sent by the source base station to the target base station. The target base station transmits the PDCP PDU(s) received from the source base station to the UE. In this way, during a period of time during the handover process, the UE may process the PDCP PDUs(s) from the source base station and the target base station by using the parameters corresponding to the source base station, so as to reduce the complexity of processing data by the UE. In fig. 3, after the UE is successfully handed over to the target base station, for example, after a core network device (e.g., an access and mobility management function (AMF) network element and a User Plane Function (UPF) network element) changes a downlink path to the target base station, that is, after the core network side completes the path change, the target base station may receive, in addition to the PDCP PDU(s) from the source base station, the PDCP SDU(s) sent from the User Plane Function (UPF) network element, and the target base station needs to process the PDCP SDU(s) received from the UPF by using parameters corresponding to the target base station, for example, the target base station obtains the PDCP PDU(s) after performing, separately performing, SN assignment, header compression, ciphering, and header addition on the PDCP SDU(s) received from the user plane function network element by using parameters corresponding to the target base station (for example, the parameters may include a header compression context, a security key, an integrity protection parameter, and the like), and then sends the obtained PDCP PDU(s) to the UE. That is, the PDCP PDU(s) received by the UE from the target base station may need to be processed by using the parameter corresponding to the source base station, or may need to be processed by using the parameter corresponding to the target base station.

The handover procedures shown in fig. 2 and 3 are by way of example only. Alternatively, the handover procedure may include other steps than those shown in fig. 2 and 3, or some, but not all, of the steps shown in fig. 2 and 3 may be performed.

Referring to fig. 3, to ensure correct transceiving of data and implement 0ms of interrupt latency, fig. 4 shows a communication method 400 provided in this embodiment of the present application, including:

s410, the first network equipment or the second network equipment sends a first message to the terminal equipment.

Accordingly, the terminal device receives a first message sent from the first network device or the second network device.

S420, the first network device sends the PDCP PDU to the terminal device.

Accordingly, the terminal device receives PDCP PDUs from the first network device.

S430, the terminal device determines a target parameter for processing the PDCP PDU according to the first message, wherein the target parameter is one of a first parameter corresponding to the first network device and a second parameter corresponding to the second network device, and the first parameter or the second parameter is used for processing the received PDCP PDU.

The determining, by the terminal device, the target parameter for processing the PDCP PDU according to the first message may include: and determining the target parameter according to the first indication information in the first message or determining the target parameter according to whether the first message is received or not.

In one possible design, the terminal device may process PDCP PDUs(s) generated by the first network device using the first parameters; the terminal device may process PDCP PDUs(s) from the second network device using the second parameters, where the PDCP PDUs(s) from the second network device are PDCP PDUs(s) received by the terminal device from the first network device. For example, the first parameter may include at least one of: a key corresponding to the first network device, a header decompression context corresponding to the first network device, and an integrity verification parameter corresponding to the first network device; the second parameter may include at least one of: a key corresponding to the second network device, a header decompression context corresponding to the second network device, and an integrity verification parameter corresponding to the second network device.

Alternatively, the second network device may be a source network device; the first network device may be a target network device.

Optionally, the first network device sends PDCP PDUs to the terminal device after the first network device receives an RRC reconfiguration complete message from the terminal device.

It should be noted that the order relationship between S410 and S420 is not limited, that is, the first network device may send the PDCP PDU first to the terminal device and then send the first message, or send the first message first to the terminal device and then send the PDCP PDU, or send the first message and the PDCP PDU simultaneously to the terminal device, or the first network device may send a part of the PDCP PDU to the terminal device and then send the first message to the terminal device; or the second network device may send the first message to the terminal device first, and the first network device sends the PDCP PDU to the terminal device; or the first network equipment sends the PDCP PDU to the terminal equipment first, and the second network equipment sends the first message to the terminal equipment; or the first network equipment sends the PDCP PDU to the terminal equipment and the second network equipment sends the first message to the terminal equipment at the same time; or after the first network equipment sends the partial PDCP PDU to the terminal equipment, the second network equipment sends the first message to the terminal equipment.

In addition, in some scenarios, the sequence of S430 and S410 is not limited, for example, the terminal device determines that the target parameter for processing the PDCP PDU is the second parameter according to that the first message is not received, and at this time, S410 is not executed.

S440, the terminal device processes the PDCP PDU received from the first network device according to the target parameter, so as to obtain the PDCP SDU.

In S420, the PDCP PDU sent by the first network device to the terminal device may be a PDCP PDU from the second network device, or a PDCP PDU obtained by the first network device processing a PDCP SDU with its corresponding parameter. If the PDCP PDU sent to the terminal equipment by the first network equipment is the PDCP PDU from the second network equipment, the terminal equipment can determine that the target parameter is a second parameter corresponding to the second network equipment according to the first message; if the PDCP PDU sent by the first network device to the terminal device is a PDCP PDU obtained by processing a PDCP SDU with a parameter corresponding to the first network device, the terminal device may determine that the target parameter is a first parameter corresponding to the first network device according to the first message.

The following case one describes a method in which a first network device sends a first message to a terminal device in S410, and the terminal device processes PDCP PDUs from the first network device using target parameters determined according to the first message sent by the first network device; the following case two describes a method in which the second network device sends a first message to the terminal device in S410, and the terminal device processes the PDCP PDU from the first network device by using the target parameter determined according to the first message sent by the second network device; case three describes a method in which a first network device sends a first message to a terminal device in S410, where the first message may include first indication information, and the terminal device processes a PDCP PDU from the first network device by using a target parameter determined by the first indication information; case four describes a method in which the second network device sends a first message to the terminal device in S410, the first message includes first indication information, and the terminal device processes the PDCP PDU from the first network device by using the target parameter determined by the first indication information.

In the first case, after the first network device receives the PDCP PDU sent by the second network device, the first network device sends all PDCP PDUs(s) received from the second network device to the terminal device, and then the first network device sends a first message to the terminal device, that is, the PDCP PDU is a PDCP PDU generated after the second network device performs PDCP SN allocation, performs header compression by using a header compression context corresponding to the second network device, performs integrity protection by using an integrity protection parameter corresponding to the second network device, encrypts a key corresponding to the second network device, adds a PDCP header, and then the second network device forwards the PDCP PDU to the first network device. It should be noted that the second network device may forward one or more PDCP PDUs to the first network device, which is not limited in the embodiment of the present application. Then, before the terminal device receives the first message (it may be understood that the terminal device does not receive the first message), the target parameter determined by the terminal device is the second parameter, and the terminal device may process the PDCP PDU from the first network device by using the second parameter to obtain the PDCP SDU, and specifically, the terminal device processes the PDCP PDU from the first network device by using at least one of a key corresponding to the second network device, a header decompression context corresponding to the second network device, and an integrity verification parameter corresponding to the second network device to obtain the PDCP SDU. After the first network device sends all PDCP PDUs(s) received from the second network device to the terminal device, for the PDCP SDUs(s) received by the first network device from the UPF network element, the first network device uses its corresponding parameters to process the PDCP SDUs(s) respectively to obtain PDCP PDUs(s), for example, for a certain PDCP SDU received from the UPF network element, the first network device performs PDCP SN allocation, performs header compression by using a header compression context corresponding to the first network device, performs integrity protection by using an integrity protection parameter corresponding to the first network device, encrypts a key corresponding to the first network device, adds a PDCP header, and so on, and generates PDCP PDUs, and then the first network device sends the PDCP PDUs to the terminal device. Therefore, after the terminal device receives the first message (it can be understood that the terminal device receives the first message), the terminal device determines that the target parameter is the first parameter corresponding to the first network device, that is, the terminal device processes the PDCP PDU from the first network device by using the first parameter corresponding to the first network device, so as to obtain the PDCP SDU. Specifically, the terminal device processes the PDCP PDU from the first network device by using at least one of a secret key corresponding to the first network device, a header decompression context corresponding to the first network device, and an integrity verification parameter corresponding to the first network device, so as to obtain a PDCP SDU. That is, in case one, the terminal device may determine the target parameter according to an opportunity of receiving the first message sent by the first network device. For example, in case one, the first message may be an RRC message, the first message is used to indicate that the terminal device does not use the second parameter to process the PDCP PDU from the first network device, or indicate that the terminal device starts to process the PDCP PDU from the first network device using the first parameter, or indicate that the terminal device releases an RRC connection with the second network device, or indicate that the PDCP PDU sent by the first network device from the second network device is ended.

In the second case, the second network device sends the first message to the terminal device, for example, after the first network device sends all PDCP PDUs(s) from the second network device to the terminal device, the first network device sends indication information to the second network device, where the indication information is used to indicate that the first network device has finished sending all PDCP PDUs(s) from the second network device to the terminal device. Then, the second network device sends the first message to the terminal device. That is, before the terminal device receives the first message (it may be understood that the terminal device does not receive the first message), all PDCP PDUs(s) received by the terminal device from the first network device originate from the second network device, that is, all PDCP PDUs(s) are sent to the first network device by the second network device after the second network device performs processing such as PDCP SN distribution, header compression, integrity protection, ciphering, PDCP header addition, and the like, and then are sent to the terminal device by the first network device, so that before the terminal device receives the first message, the terminal device processes the PDCP PDUs from the first network device by using the second parameters corresponding to the second network device, and obtains PDCP SDUs. Specifically, the terminal device processes the PDCP PDU from the first network device by using at least one of a secret key corresponding to the second network device, a header decompression context corresponding to the second network device, and an integrity verification parameter corresponding to the second network device, so as to obtain a PDCP SDU. After the first network device sends all PDCP PDUs(s) from the second network device to the terminal device, for the PDCP SDUs(s) received by the first network device from the UPF, the first network device processes the PDCP SDUs(s) by using its corresponding parameters, respectively, to obtain PDCP PDUs(s), for example, for a certain PDCP SDU received from the UPF, the first network device performs PDCP SN allocation, performs header compression by using a header compression context corresponding to the first network device, performs integrity protection by using an integrity protection parameter corresponding to the first network device, encrypts a key corresponding to the first network device, adds a PDCP header, and so on, and generates PDCP PDUs, and then the first network device sends the PDCP PDUs to the terminal device. Therefore, after the terminal device receives the first message (it can be understood that the terminal device receives the first message), the terminal device determines that the target parameter is the first parameter corresponding to the first network device, that is, the terminal device processes the PDCP PDU from the first network device by using the first parameter corresponding to the first network device, so as to obtain the PDCP SDU. Specifically, the terminal device processes the PDCP PDU from the first network device by using at least one of a secret key corresponding to the first network device, a header decompression context corresponding to the first network device, and an integrity verification parameter corresponding to the first network device, so as to obtain a PDCP SDU. That is, in case two, the terminal device may determine the target parameter according to the timing of receiving the first message sent by the second network device. For example, in case two, the first message may be an RRC message, the first message being used to indicate that the terminal device no longer uses the second parameter to process PDCP PDUs from the first network device, or to indicate that the terminal device starts to process PDCP PDUs from the first network device using the first parameter, or to indicate that the terminal device releases an RRC connection with the second network device, or the first message being used to indicate that PDCP PDUs sent by the first network device from the second network device end.

In case three, the first network device sends a first message to the terminal device, where the first message includes first indication information, and the first indication information is used to assist the terminal device in determining a target parameter to be used when processing the PDCP PDU received from the first network device. Optionally, before the first network device sends the first message to the terminal device, the first network device receives a second message sent by the second network device, where the second message is used to notify the first network device to allocate PDCP SNs to received PDCP SDUs to which PDCP SNs are not allocated, and specifically, the second message includes second indication information, where the second indication information is used to indicate a starting SN value when the first network device performs PDCP SN allocation. Optionally, the second indication information may be of bearer granularity, that is, when the first network device performs PDCP SN allocation corresponding to each bearer, each bearer carries a corresponding initial SN value, and the initial SN values corresponding to different bearers may be the same or different. Corresponding to a certain bearer, the first network device allocates PDCP SNs to the received PDCP SDUs to which PDCP SNs are not allocated according to the second indication information, and specifically, the first network device allocates a starting SN value to the first received PDCP SDU to which PDCP SNs are not allocated, and sequentially allocates PDCP SNs sequentially increasing after the starting SN value to subsequent PDCP SDUs to which PDCP SNs are not allocated. Optionally, the first network device may determine, according to the second indication information, first indication information, where the first indication information includes a first PDCP SN that is the last PDCP PDU received from the first network device and processed using the second parameter corresponding to the second network device, or the first indication information includes a largest first PDCP SN corresponding to a PDCP PDU obtained after processing using the second parameter corresponding to the second network device, or the first indication information is used to indicate that the terminal device needs to process, by using the second parameter, a PDCP PDU(s) before the PDCP SN corresponding to the PDCP PDU(s) received from the first network device is the first PDCP SN, and needs to process, by using the first parameter, a PDCP PDU(s) after the PDCP SN corresponding to the PDCP SN is the first PDCP SN. Optionally, the first indication information may be bearer granular, that is, each carries a respective corresponding first PDCP SN, and the first PDCP SNs corresponding to different bearers may be the same or different. The first network equipment includes the first indication information in a first message and sends the first indication information to the terminal equipment. Optionally, the first message may also be used to instruct the terminal device to release the RRC connection with the second network device.

Taking a certain bearer as an example for explanation, specifically, corresponding to the bearer, the second indication information is used to indicate that a starting PDCP SN when the first network device performs PDCP SN assignment on PDCP SDUs to which PDCP SNs are not allocated is X +1, then the PDCP SNs sequentially assigned to the received PDCP SDUs(s) to which PDCP SNs are not allocated by the first network device are X +1, X +2, X +3 \82303030, X + p, p are positive integers, where the first network device allocates one PDCP SN for one PDCP SDU. In addition, corresponding to the bearer, according to the second indication information, the first network device may learn that a maximum PDCP SN(s) of PDCP SNs(s) respectively corresponding to PDCP PDUs(s) received from the second network device is X (for example, the aforementioned first PDCP SN is X), then the first network device may determine, according to the second indication information, the first indication information, that is, the first indication information includes X, and the terminal device determines, according to X, whether to process the PDCP PDU received from the first network device by using a second parameter corresponding to the second network device or a first parameter corresponding to the first network device, specifically, if the PDCP SN of the PDCP PDU received from the first network device is less than or equal to X, the terminal device processes the PDCP PDU from the first network device by using the second parameter corresponding to the second network device, to obtain PDCP SDU, that is, the terminal device processes the PDCP PDU received from the first network device by using the second parameter corresponding to the second network device; if the PDCP SN of the PDCP PDU received from the first network equipment is larger than X, the terminal equipment adopts the first parameter corresponding to the first network equipment to process the PDCP PDU from the first network equipment to obtain the PDCP SDU, namely the terminal equipment adopts the first parameter corresponding to the first network equipment to respectively process the PDCP PDU with the PDCP SN of X +1, X +2, 8230, 823030, X + p received from the first network equipment.

It should be noted that, in the third case, it is described that the first message sent by the first network device to the terminal device depends on the second message received by the first network device from the second network device, but the embodiment of the present application is not limited to this, and the first message sent by the first network device to the terminal device may not depend on the second message from the second network device, and may also be sent autonomously by the first network device.

In a fourth case, the second network device may know which PDCP PDUs(s) are sent to the first network device by itself, and also may know PDCP SNs corresponding to the PDCP PDUs(s), and according to the PDCP SNs corresponding to the PDCP PDUs(s), the second network device may determine, as the first PDCP SN, the PDCP SN corresponding to the last PDCP SDU sent to the first network device and processed by using parameters (such as a header compression context, a key, and the like) corresponding to the second network device, in other words, the second network device may determine, as the first PDCP SN, the largest PDCP SN of the PDCP SNs corresponding to the PDCP PDUs(s) sent to the first network device, so as to assist the terminal device to determine which PDCP PDUs(s) are processed by using the first parameters corresponding to the first network device, and which PDCP PDUs(s) are processed by using the second parameters corresponding to the second network device. Therefore, the second network device may send a first message to the terminal device, where the first message includes first indication information, where the first indication information includes a last first PDCP SN processed by using a second parameter corresponding to the second network device for PDCP PDUs from the first network device, or the first indication information includes a largest first PDCP SN corresponding to PDCP PDUs obtained after processing by using the second parameter corresponding to the second network device, or the first indication information is used to indicate that the terminal device needs to process second parameters for PDCP PDUs(s) before the corresponding PDCP SN is the first PDCP SN in PDCP PDUs(s) received from the first network device, and needs to process first parameters for PDCP PDUs(s) after the corresponding PDCP SN is the first PDCP SN in PDCP PDUs(s) received from the first network device. Optionally, the first indication information may be bearer granular, that is, each carries a respective corresponding first PDCP SN, and the first PDCP SNs corresponding to different bearers may be the same or different.

Optionally, before the second network device sends the first message to the terminal device, or after the second network device sends the first message to the terminal device, or while the second network device sends the first message to the terminal device, the second network device sends a second message to the first network device, where the second message is used to notify the first network device to allocate PDCP SNs to received PDCP SDUs to which PDCP SNs are not allocated, specifically, the second message includes second indication information, the second indication information is used to indicate a starting SN value when the first network device performs PDCP SN allocation, optionally, the second indication information may be of bearer granularity, that is, corresponding to each bearer, when the first network device performs PDCP SN allocation, each bearer carries a respective corresponding starting SN value, and corresponding starting SN values of different bearers may be the same or different. Corresponding to a certain bearer, the first network device allocates PDCP SNs to the received PDCP SDUs to which PDCP SNs are not allocated according to the second indication information, specifically, the first network device allocates a starting SN value to the first received PDCP SDU to which PDCP SNs are not allocated, and sequentially allocates sequentially increasing PDCP SNs after the starting SN value to subsequent PDCP SDUs to which PDCP SNs are not allocated.

Taking a certain bearer as an example, specifically, the second network device sends PDCP PDUs(s) with PDCP SNs of m, m +1, m +2, \ 8230 \ 8230:, X to the first network device corresponding to the bearer, where m is an integer greater than or equal to zero. The second network device may determine that a maximum PDCP SN of the PDCP SNs respectively corresponding to the PDCP PDUs(s) sent by the second network device to the first network device is X (the aforementioned first PDCP SN), and therefore, the first indication information sent by the second network device to the terminal device may include X, the terminal device determines, according to X, whether to process the PDCP PDU received from the first network device by using a second parameter corresponding to the second network device or a first parameter corresponding to the first network device, specifically, if the PDCP SN of the PDCP PDU received from the first network device is less than or equal to X, the terminal device processes the PDCP PDU from the first network device by using the second parameter corresponding to the second network device, that is, the terminal device processes the PDCP SN received from the first network device by using the second parameter corresponding to the second network device; if the PDCP SN of the PDCP PDU received from the first network equipment is larger than X, the terminal equipment processes the PDCP PDU from the first network equipment by adopting the first parameter corresponding to the first network equipment, namely the terminal equipment processes the PDCP PDU of which the PDCP SN received from the first network equipment is X +1, X +2, 8230, X + p by adopting the first parameter corresponding to the first network equipment.

Optionally, in the example description of the third and fourth cases, the first indication information sent by the second network device or the first network device to the terminal device may include X, and certainly the first indication information may further include other values, for example, X-1, X +1, or X +2, and the terminal device may determine X according to X-1, X +1, or X +2 indicated by the first indication information, for example, offsets corresponding to X-1, X +1, or X +2 are +1, -1, or-2, for example, the terminal device may determine X according to X +2 and offset-2 indicated by the first indication information, in this embodiment, the content indicated by the first indication information is not limited, as long as the terminal device may determine that the PDCP PDU received from the first network device and having the PDCP SN less than or equal to X needs to be processed by using the second parameter corresponding to the second network device according to the first indication information, and the PDCP PDU received from the first network device and having the SN X +1, X + 82302, respectively needs to be processed by using the first parameter corresponding to the first network device. For example, in the above example, the first indication information may be represented by 0 or 1 or any integer less than or equal to X; for another example, the first indication information may be represented by X + N, and the terminal device determines X according to X + N, where N is an integer (positive integer or negative integer), and N is a preset value or a value specified by a protocol, and the like, and this is not limited in this embodiment of the application.

Optionally, in the third and fourth cases, the first indication information included in the first message may be of bearer granularity, that is, one bearer may correspond to one indication information, for example, in a case that there are two bearers, the first message may include two first indication information, where each first indication information corresponds to one bearer, for example, the first message may be an RRC message or a downlink control message (DCI) or a Medium Access Control (MAC) Control Element (CE). Optionally, in the above four cases, the first message may be of bearer granularity, that is, one bearer corresponds to one first message, for example, in a case that there are two bearers, there may be two first messages, and one first message corresponds to one bearer, for example, the first message may be a packet data convergence protocol control protocol data unit (PDCP control PDU). Specifically, corresponding to the third case, in the case that there are two bearers (e.g., bearer 1 and bearer 2), the first network device may send two PDCP control PDUs to the terminal device, where one PDCP control PDU corresponds to bearer 1, the other PDCP control PDU corresponds to bearer 2, the PDCP control PDU corresponding to bearer 1 includes first indication information (e.g., a first PDCP SN) corresponding to the bearer 1, and the PDCP control PDU corresponding to bearer 2 includes first indication information (e.g., a first PDCP SN) corresponding to the bearer 2, where the first PDCP SN corresponding to bearer 1 and the first PDCP SN corresponding to bearer 2 may be the same or different, which is not limited in this embodiment; corresponding to the fourth case, in the case that there are two bearers (e.g., bearer 1 and bearer 2), the second network device may send two PDCP control PDUs to the terminal device, where one PDCP control PDU corresponds to bearer 1, the other PDCP control PDU corresponds to bearer 2, the PDCP control PDU corresponding to bearer 1 includes the first indication information (e.g., the first PDCP SN) corresponding to the bearer 1, and the PDCP control PDU corresponding to bearer 2 includes the first indication information (e.g., the first PDCP SN) corresponding to the bearer 2, where the first PDCP SN corresponding to bearer 1 and the first PDCP SN corresponding to bearer 2 may be the same or different, which is not limited in this embodiment.

It should be noted that the PDCP PDU(s) sent by the second network device to the first network device may be one PDCP PDU or multiple PDCP PDUs.

It should be noted that, in the embodiments of the present application, the PDCP SN may be a value determined according to a Hyper Frame Number (HFN) of a higher bit and a PDCP SN of a lower bit. For example, when comparing the size relationship between the PDCP SNs of the PDCP PDUs received from the first network device and the first PDCP SN, the PDCP SN of the PDCP PDU received from the first network device is determined according to the HFN of the higher order and the PDCP SN of the lower order, and the first PDCP SN is also determined according to the HFN of the higher order and the PDCP SN of the lower order, so that the size relationship between the PDCP SNs can be compared reasonably.

Optionally, the sending, by the first network device, the PDCP PDU(s) to the terminal device by the terminal device described in this embodiment of the present application, and the receiving, by the terminal device, the PDCP PDU(s) from the first network device may include: after the first network device performs a series of processing on the PDCP PDU(s) through the RLC layer, the MAC layer, the PHY layer, and the like, the first network device sends the data packet to the terminal device, and the terminal device performs decapsulation on the PHY layer, the MAC layer, and the RLC layer on the received data packet to obtain the PDCP PDU(s).

It should be noted that, in this embodiment of the present application, when the aforementioned first network device processes the PDCP SDU by using a corresponding parameter of the first network device, the parameter is a parameter that the first network device needs to perform header compression, integrity protection, ciphering, or adding a PDCP header; the aforementioned first parameter corresponding to the first network device is a parameter required by the terminal device to perform header decompression, integrity verification, decryption, or delete the PDCP header on the received PDCP PDU. In other words, the corresponding parameter of the first network device is a parameter required by the first network device to process the PDCP SDU, and the first parameter corresponding to the first network device is a parameter required by the terminal device to process the PDCP PDU from the first network device. When the aforementioned second network device needs to process the PDCP SDU using its corresponding parameter, the parameter is a parameter that the second network device needs to perform header compression, integrity protection, ciphering or adding a PDCP header; the aforementioned second parameter corresponding to the second network device is a parameter required by the terminal device to perform header decompression, integrity verification, decryption, or PDCP header deletion on the received PDCP PDU. In other words, the corresponding parameter of the second network device is a parameter required by the second network device to process the PDCP SDU, the corresponding second parameter of the second network device is a parameter required by the terminal device to process the PDCP PDU received from the first network device, and the PDCP PDU received from the first network device is the PDCP PDU sent by the second network device to the first network device.

The communication method provided in the embodiment of the present application is described below with reference to fig. 5 to 8 by way of example, where fig. 5 to 8 describe using a first network device as a target base station, a second network device as a source base station, and a terminal device as a UE as an example.

Taking the NR system as an example, fig. 5 illustrates a communication method 500 provided in an embodiment of the present application, including:

s501, the source base station performs measurement control on the UE.

For example, the source base station may send an RRC message containing measurement configuration information to the UE. At this time, data scheduling may be performed between the UE and the source base station, and the PDCP PDU(s) sent by the source base station to the UE is obtained by processing using corresponding parameters (such as a header compression context, a key, and integrity protection parameters) of the source base station.

And S502, after the UE carries out measurement according to the measurement configuration information in the S501, reporting a measurement report to the source base station, wherein the measurement report comprises results obtained by measuring one or more cells by the UE.

S503, the source base station performs a handover decision (handover decision) according to the measurement report, specifically, the source base station determines that the UE needs to be handed over, and determines the target base station.

S504, the source base station sends a handover request message to the target base station, and the handover request message is used for requesting the target base station to prepare for the handover of the UE.

S505, if the target base station can accommodate handover of the UE, sending a handover request Acknowledgement (ACK) message to the source base station, where the ACK is an abbreviation of acknowledge.

S506, the source base station sends an RRC reconfiguration (RRC reconfiguration) message to the UE, for example, in the new wireless NR system, the RRC reconfiguration message carries a synchronization reconfiguration (reconfiguration within sync) information element. After the source base station sends the RRC reconfiguration message indicating that the UE performs handover to the UE, the source base station may continue to perform data transmission with the UE. S507, the UPF sends PDCP SDU (S) to the source base station.

It should be noted that S507 may be executed before S506, that is, S507 is not limited by other steps. The UPF network element can send one or more PDCP SDUs to the source base station.

S508, the source base station processes part or all of the PDCP SDUs (S) received from the UPF by using corresponding parameters (such as a header compression context corresponding to the source base station, a key corresponding to the source base station and the like) of the source base station to obtain the PDCP PDUs (S), and then the source base station sends part or all of the PDCP PDUs (S) to the UE.

S509, the source base station processes part or all of the PDCP SDUs (S) received from the UPF by using corresponding parameters (e.g., a header compression context corresponding to the source base station, a key corresponding to the source base station, etc.) to obtain PDCP PDUs (S), and then the source base station sends part or all of the PDCP PDUs (S) to the target base station, which may be referred to as data forwarding.

Alternatively, part or all of the PDCP SDUs (S) in S508 and part or all of the PDCP SDUs (S) in S509 may be the same or different PDCP SDUs (S).

For example, in order to enhance the reliability of data transmission, optionally, in S508 and S509, part or all of the PDCP SDUs (S) may be the same PDCP SDU (S), that is, the source base station may copy data, and for a PDCP SDU corresponding to a certain PDCP SN, the source base station may generate two identical PDCP PDUs, one of which is sent to the UE in step S508, and the other is sent to the target base station in step S509.

Note that the order between S508 and S509 is not limited at all.

S510, the target base station buffers one or more PDCP PDUs received from the source base station.

S511, after S506, the UE synchronizes with the target base station. Specifically, for example, the UE performs a random access procedure with the target base station. The UE may continue to maintain RRC connection/data transmission with the source base station while the UE performs a random access procedure with the target base station.

S512, after the UE completes synchronization with the target base station, for example, after the UE succeeds in a random access procedure with the target base station, the UE sends an RRC reconfiguration complete (RRC reconfiguration complete) message to the target base station.

It should be noted that, no sequence restriction exists between S511 and S508-S510, that is, the synchronization process between the UE and the target base station, the data transmission process between the UE and the source base station, and the PDCP PDU (S) forwarding process between the source base station and the target base station, and there is no sequence restriction, and they may be performed simultaneously or sequentially.

S513, the target base station transmits to the UE the one or more PDCP PDUs received from the source base station in S509. For example, the target base station sends PDCP PDU(s) to the UE after receiving the RRC reconfiguration complete message sent by the UE.

S514, the target base station sends a path switch request (path switch request) message to the AMF.

S515, the AMF sends a user plane update request (user plane update request) message to the UPF.

S516, the UPF sends an end indicator (end marker) to the source base station, where the end indicator is used to indicate that the source base station UPF does not send downlink data to the source base station any more, that is, the source base station does not receive PDCP SDU from the UPF any more.

S517, after the network element of the core network completes the path change or the bearing change, the UPF sends a user plane update confirmation message to the AMF.

It should be noted that the sequence between S516 and S517 is not limited at all, and S516 may be performed before or after S517 or simultaneously.

S518, the AMF transmits a path change request confirm message to the target base station after S517.

Optionally, the method 500 further comprises: s519, after S512, the target base station sends third indication information to the source base station, where the third indication information is used to instruct the source base station to send a second message to the target base station.

S520, after S516, the source base station sends the second message to the target base station, that is, the downlink ending instruction in S516 may be used to trigger the source base station to send the second message to the target base station.

If S519 exists, in S520, the source base station sends a second message to the target base station according to the third indication information in S519, where the second message is used to notify the target base station to allocate PDCP SNs to the received PDCP SDUs to which PDCP SNs are not allocated. That is, the source base station may transmit the second message to the target base station based on the downlink end instruction information in S516, or may transmit the second message to the target base station based on the third instruction information transmitted by the target base station in S519.

Alternatively, the second message may be a sequence number status transfer (SN status transfer) message.

Optionally, the second message may include the second indication information in the method 400, which is not described herein again.

Optionally, the target base station activates its PDCP entity (or PDCP layer) corresponding to the corresponding bearer upon receiving the second message, for example, the PDCP entity (or PDCP layer) of the target base station starts to perform corresponding processing on data packets on the bearer corresponding to the PDCP entity. Specifically, the PDCP entity of the target base station performs PDCP SN distribution, performs header compression using a header compression context corresponding to the target base station, performs integrity protection using an integrity protection parameter corresponding to the target base station, encrypts using a key corresponding to the target base station, adds a PDCP packet header, and so on.

521a, the source base station sends a first message to the UE, where the first message may be an RRC message, or a PDCP control PDU, or a MAC CE, or DCI, or others, and refer to the explanation of S410 specifically, which is not described herein again. The first message may include the first indication information in the method 400, and the first indication information is not described in detail here.

As an alternative manner S521b of 521a, the target base station sends a first message to the UE according to the second message, where the first message includes the first indication information in the method 400.

Optionally, in S521 (b), the target base station sends the first message to the UE according to the second indication information included in the second message.

S522, after the path change and the bearer change on the core network side are completed, that is, after the steps S514-S518 are completed, the UPF sends one or more downlink PDCP SDUs to the target base station.

S523, the target base station processes the PDCP SDU received from the UPF by using its corresponding parameters (e.g., the header compression context corresponding to the target base station, the key corresponding to the target base station, etc.), for example, for the PDCP SDU received from the UPF in S522, the target base station performs PDCP SN assignment, performs header compression by using the header compression context corresponding to the target base station, performs encryption by using the key corresponding to the target base station, and obtains a PDCP PDU, and sends the PDCP PDU to the UE.

It should be noted that S522 may be after S517, and there is no restriction on the order of any step in S518-S521a/S521b, and may be before or after any step in S518-S521a/S521 b. In other words, the UPF sends the PDCP SDU to the target base station, and then the target base station sends the corresponding PDCP PDU, which is generated after the PDCP SDU is processed by using the corresponding parameter of the target base station, to the UE.

It should also be noted that, optionally, any step of S509 and S511-S523 has no sequential limitation, and any step of S513 and S514-S523 has no sequential limitation. For example, after S521a or S521b, the target base station may send, to the terminal device, in addition to the PDCP PDU (S) generated after processing with the parameters corresponding to the target base station, the PDCP PDU received from the source base station.

S524, the UE determines the target parameters needed for processing the PDCP PDU received from the target base station according to the first indication information in the S521a or the S521 b. In other words, in S521a or S521b, the first indication information included in the first message is used to assist the UE to determine reasonable target parameters, and the UE processes the PDCP PDU received from the target base station by using the target parameters, specifically, the PDCP PDU received from the target base station includes the PDCP PDU (S) received from S513 and/or the PDCP PDU (S) received from S523. Or it can be understood that, for PDCP PDUs received by the UE from the source base station or the target base station with PDCP SNs less than or equal to the first PDCP SN indicated by the first indication information, the UE may perform processing using the second parameter corresponding to the source base station (e.g., performing header decompression using a header decompression context corresponding to the source base station, performing integrity verification using an integrity verification parameter corresponding to the source base station, performing decryption using a key corresponding to the source base station, etc.); for PDCP PDUs received by the UE from the source base station or the target base station that are greater than the first PDCP SN indicated by the first indication information, the UE may perform processing using the first parameter corresponding to the target base station (e.g., perform header decompression using a header decompression context corresponding to the target base station, perform integrity verification using an integrity verification parameter corresponding to the target base station, perform decryption using a key corresponding to the target base station, etc.).

Optionally, the first message in S521a or S521b may also be used to instruct the UE to release the RRC connection with the source base station. Further, the UE releases a user plane protocol stack corresponding to the source base station (e.g., the UE releases a PHY entity/MAC entity/RLC entity/PDCP entity/SDAP entity corresponding to the source base station), and deletes parameters related to the source base station (e.g., a secret key of the source base station, a header compression context of the source base station, a PHY/MAC/RLC/PDCP/Service Data Adaptation Protocol (SDAP)/RRC configuration information, etc.) corresponding to the source base station.

Optionally, in the method 500, before the UE releases the RRC connection/data transmission with the source base station, the UE may process one or more PDCP PDUs received from the source base station using a second parameter corresponding to the source base station (e.g., a header decompression context corresponding to the source base station, a key corresponding to the source base station, etc.).

Taking a certain bearer as an example, in the method 500, for a data packet with a PDCP SN less than or equal to the first PDCP SN transmitted on the bearer, the protocol stack architecture of the UE and the network device side (i.e., the source base station and the target base station) is as shown in fig. 6, and fig. 6 takes transmission of a certain bearer as an example, the source base station side maintains its own protocol stack (e.g., PHY1/MAC1/RLC1/PDCP 1) corresponding to the certain bearer, and the target base station maintains its own protocol stack (e.g., PHY2/MAC2/RLC2/PDCP 2) to illustrate that the PDCP entity (or PDCP layer) is in bearer granularity, and different bearers carry corresponding PDCP entities (or PDCP layers). For a data packet with a PDCP SN greater than the first PDCP SN transmitted on the bearer, the protocol stack architecture of the UE and the network device side (i.e., the source base station and the target base station) is as shown in fig. 7, where in fig. 7, taking transmission of a certain bearer as an example, the target base station maintains its own protocol stack (e.g., PHY2/MAC2/RLC2/PDCP 2) corresponding to the certain bearer, and the UE maintains PHY2, MAC2, RLC2, and PDCP2 corresponding to the target base station, that is, for a PDCP PDU received from PHY2, MAC2, and RLC2 corresponding to the target base station, the UE needs to use the PDCP2 corresponding to the target base station (i.e., using parameters such as a header decompression context corresponding to the target base station and a key corresponding to the target base station) for processing.

For a certain bearer, the PDCP at the terminal device side has two implementation manners, that is, before handover, data of the bearer is transmitted at a source base station, and corresponds to the bearer, and the UE side has a PDCP1 corresponding to the source base station, and after receiving an RRC reconfiguration message sent by the source base station and instructing the UE to perform handover, the UE keeps data transmission with the source base station, that is, the UE keeps a user plane protocol stack corresponding to the source base station, that is, the UE does not reset (reset) or re-establish (re-acknowledgement) of layer 2 (layer 2 includes MAC1/RLC1/PDCP1 protocol layers) to the user plane protocol stack corresponding to the source base station. And after receiving the RRC reconfiguration message, the UE establishes a user plane protocol stack corresponding to the target base station, that is, corresponding to the bearer, and establishes a PHY2/MAC2/RLC2 layer corresponding to the target base station, optionally, the UE may establish a PDCP2 layer corresponding to the target base station, but does not activate and use the PDCP2, and the UE does not activate the PDCP2 until the UE needs to process the received downlink data packet by using the first parameter (such as the key, the header decompression context, the integrity verification parameter, and the like) corresponding to the target base station. In the first mode, the UE may have two PDCP entities corresponding to the certain bearer, where one PDCP entity corresponds to the source base station and the other PDCP entity corresponds to the target base station. In the second mode, after receiving the RRC reconfiguration message, the UE establishes PHY2/MAC2/RLC2 corresponding to the target base station, but does not establish PDCP2 corresponding to the target base station, that is, corresponding to the bearer, the UE has only one PDCP entity, and the PDCP entity maintained by the UE supports/stores/maintains both the second parameter corresponding to the source base station and the first parameter corresponding to the target base station.

Specifically, as shown in fig. 6, for the certain bearer, the UE maintains PHY1, MAC1, and RLC1 corresponding to the source base station, and the UE maintains PHY2, MAC2, and RLC2 corresponding to the target base station, and the UE only maintains PDCP1, that is, the PDCP1 may process PDCP PDUs received from the source base station and/or the target base station. In fig. 7, the PDCP2 may be established after the UE receives the RRC reconfiguration message (i.e., after receiving the handover message, the UE corresponds to a certain bearer, and in addition to maintaining/maintaining the PDCP1 corresponding to the source base station, the UE also establishes the PDCP2 corresponding to the target base station), or the PDCP2 may be a PDCP entity that simultaneously supports/stores/maintains the second parameter corresponding to the source base station and the first parameter corresponding to the target base station (i.e., after receiving the handover message, the UE maintains/maintains the PDCP1 corresponding to the source base station, and the PDCP1 may support the second parameter corresponding to the source base station and the first parameter corresponding to the target base station, that is, the PDCP1 may process data packets from the source base station and/or the target base station), or after receiving the handover message, the UE may change the maintained/maintained PDCP1 corresponding to the source base station to correspond to the target base station, that is, the PDCP1 becomes the PDCP2 corresponding to the target base station).

Fig. 8 shows a communication method 800 provided in an embodiment of the present application, including:

S801-S820 are the same as S501-S520.

Specifically, after S820, that is, after the target base station receives the second message and the target base station successfully sends all buffered PDCP PDUs (S) sent by the source base station to the UE, corresponding to each bearer, the target base station respectively activates its own PDCP layer corresponding to each bearer, for example, for any bearer, the PDCP layer of the target base station starts to perform corresponding processing on a data packet on the bearer, for example, specifically, the PDCP layer of the target base station performs PDCP SN allocation (for example, for a certain bearer, the PDCP SDU (S) without allocated PDCP SN starts from (X + 1) and performs PDCP SN allocation, where the first PDCP SN is X), performs header compression using a header compression context corresponding to the target base station, performs integrity protection using an integrity protection parameter corresponding to the target base station, performs ciphering using a key corresponding to the target base station, and adds a PDCP packet header.

S821, after the target base station sends all buffered PDCP PDUs (S) sent by all the source base stations to the UE, the target base station sends a first message to the UE. The detailed description of the first message may refer to the first message in the method 400, and is not described again.

As an alternative implementation manner of S821, for a certain bearer, after the target base station sends all buffered PDCP PDUs (S) sent by all source base stations to the UE, the target base station sends a third message to the source base station, where the third message is used to indicate that the target base station successfully sends all buffered PDCP PDUs (S) sent by all source base stations to the UE, and after the source base station receives the third message, the source base station sends the first message to the UE, where specific description of the first message may refer to the first message in method 400, and is not repeated.

S822-S823 are the same as S522-S523.

S824, the UE determines target parameters for processing the PDCP PDU received from the target base station according to the first message. Specifically, before the UE receives the first message, the target parameter determined by the UE is a second parameter corresponding to the source base station; after receiving the first message, the target parameter determined by the UE is the first parameter corresponding to the target base station.

In the method 800, after the target base station has sent all PDCP PDUs from the source base station(s), the target base station sends a first message to the UE, so that the UE processes one or more PDCP PDUs received from the target base station by using a second parameter corresponding to the source base station before receiving the first message; and after receiving the first message, the UE processes one or PDCP PDU received from the target base station by using the first parameter corresponding to the target base station. Or it can be understood that, before the UE receives the first message, for the PDCP PDU(s) received by the UE from the source base station or the target base station, the UE may perform processing using the second parameter corresponding to the source base station (e.g., performing header decompression using a header decompression context corresponding to the source base station, performing integrity verification using an integrity verification parameter corresponding to the source base station, performing decryption using a key corresponding to the source base station, etc.); after the UE receives the first message, for the PDCP PDU(s) received by the UE from the source base station or the target base station, the UE may perform processing using the first parameter corresponding to the target base station (e.g., performing header decompression using a header decompression context corresponding to the target base station, performing integrity verification using an integrity verification parameter corresponding to the target base station, performing decryption using a key corresponding to the target base station, etc.).

Optionally, after receiving the RRC reconfiguration message instructing the UE to perform handover in S806, the UE may obtain/generate a key corresponding to the target base station, an integrity verification parameter corresponding to the target base station, and a header decompression context corresponding to the target base station, but the UE does not use the key corresponding to the target base station, the integrity verification parameter corresponding to the target base station, and the header decompression context corresponding to the target base station; optionally, in S806, the RRC reconfiguration message may include fourth indication information, where the fourth indication information indicates that the UE processes data received from the source base station and/or the target base station only using parameters corresponding to the source base station (e.g., a key corresponding to the source base station, integrity verification parameters corresponding to the source base station, and a header decompression context corresponding to the source base station) before releasing the RRC connection/data transmission with the source base station.

Optionally, the first message of S821 may also be used to instruct the UE to release the RRC connection with the source base station, so that the UE may release the RRC connection with the source base station and stop data transmission with the source base station. Further, the UE releases the user plane protocol stack corresponding to the source base station (e.g., the UE releases the PHY entity/MAC entity/RLC entity/PDCP entity/SDAP entity corresponding to the source base station), and deletes parameters related to the source base station (e.g., keys of the source base station, header compression context of the source base station, PHY/MAC/RLC/PDCP/SDAP/RRC configuration information corresponding to the source base station, etc.).

Optionally, in the method 800, before the UE releases the RRC connection/data transmission with the source base station, the UE may process one or more PDCP PDUs received from the source base station using parameters corresponding to the source base station (e.g., a header decompression context corresponding to the source base station, a key corresponding to the source base station, etc.).

Taking a certain bearer as an example, in the method 800, for the bearer, before the UE receives the first message, the protocol stack architectures of the UE and the network device sides (i.e., the source base station and the target base station) are as shown in fig. 6, taking transmission of the certain bearer as an example, the source base station side maintains its own protocol stack (e.g., PHY1/MAC1/RLC1/PDCP 1) and the target base station maintains its own protocol stack (e.g., PHY2/MAC2/RLC2/PDCP 2) corresponding to the certain bearer. It should be noted that the PDCP entity (or PDCP layer) is bearer granular, and different bearers carry the PDCP entity (or PDCP layer) corresponding thereto. After the UE receives the first message, protocol stack architectures of the UE and the network device sides (i.e., the source base station and the target base station) are as shown in fig. 7, where in fig. 7, taking transmission of a certain bearer as an example, the target base station maintains its own protocol stack (e.g., PHY2/MAC2/RLC2/PDCP 2) corresponding to the certain bearer, and the UE maintains PHY2, MAC2, RLC2, and PDCP2 corresponding to the target base station, that is, for PDCP PDUs received from PHY2, MAC2, and RLC2 corresponding to the target base station, the UE needs to use PDCP2 corresponding to the target base station (i.e., using parameters such as a header decompression context corresponding to the target base station, and a key corresponding to the target base station) for processing.

For a certain bearer, the PDCP at the terminal side has two implementation manners, one is, before handover, data of the bearer is transmitted at a source base station, and corresponds to the bearer, and the UE side has a PDCP1 corresponding to the source base station, and after receiving an RRC reconfiguration message sent by the source base station and instructing the UE to perform handover, the UE keeps data transmission with the source base station, that is, the UE keeps a user plane protocol stack corresponding to the source base station, that is, the UE does not perform reset (reset) or re-establishment (re-acknowledgement) of layer 2 (layer 2 includes an MAC1/RLC1/PDCP1 protocol layer) on the user plane protocol stack corresponding to the source base station. And after the UE receives the RRC reconfiguration message, the UE establishes a user plane protocol stack corresponding to the target base station, namely corresponding to the bearer, and the UE establishes a PHY2/MAC2/RLC2 layer corresponding to the target base station. Optionally, the UE may establish the PDCP2 corresponding to the target base station, but does not activate the PDCP2, until the UE needs to process the received downlink data packet by using the first parameter (e.g., the key, the header decompression context, the integrity verification parameter, etc.) corresponding to the target base station, the UE does not activate the PDCP2. In the first mode, the UE may have two PDCP entities corresponding to the certain bearer, where one PDCP entity corresponds to the source base station and the other PDCP entity corresponds to the target base station. In the second mode, after the UE receives the RRC reconfiguration message, corresponding to the bearer, the UE establishes PHY2/MAC2/RLC2 corresponding to the target base station, but does not establish PDCP2 corresponding to the target base station, that is, corresponding to the bearer, the UE has only one PDCP entity, and the PDCP entity maintained by the UE supports/stores/maintains both the second parameter corresponding to the source base station and the first parameter corresponding to the target base station. Specifically, as shown in fig. 6, for the certain bearer, the UE maintains PHY1, MAC1, and RLC1 corresponding to the source base station, and the UE maintains PHY2, MAC2, and RLC2 corresponding to the target base station, and the UE only maintains PDCP1, that is, the PDCP1 may process PDCP PDUs received from the source base station and/or the target base station. That is, PDCP2 in fig. 7, corresponds to a first method, where PDCP2 may be established after the UE receives the RRC reconfiguration message (that is, after receiving the handover message, it corresponds to a certain bearer, and the UE, in addition to maintaining/maintaining PDCP1 corresponding to the source base station, also establishes PDCP2 corresponding to the target base station), or corresponds to a second method, where PDCP2 may be a PDCP entity that supports/stores/maintains both the second parameter corresponding to the source base station and the first parameter corresponding to the target base station (that is, after receiving the handover message, it corresponds to a certain bearer, and the UE maintains/maintains PDCP1 corresponding to the source base station, where PDCP1 may support the second parameter corresponding to the source base station and the first parameter corresponding to the target base station, that is, PDCP1 may process data packets from the source base station and/or the target base station), or after the UE receives the handover message, it corresponds to a certain bearer, and the UE may change PDCP1 corresponding to the target base station, that is, that PDCP1 becomes PDCP2 corresponding to the target base station.

It should be noted that the flows shown in fig. 2 to fig. 5 and fig. 8 are merely exemplary, and the sequence number of each step in the drawings is for clarity of description, but the sequence number of each step does not limit the order of execution in the method, for example, a smaller sequence number may be executed before or after a larger sequence number, and the embodiment of the present application does not limit this. Optionally, each step is an optional step, in different implementations, different steps may be adopted, or still other steps may be executed but are not shown in the drawings, and this is not limited by the embodiment of the present application.

It is to be understood that the method and operations implemented by the terminal device in the foregoing method embodiments may also be implemented by a component (e.g., a chip or a circuit) available to the terminal device, and the method and operations implemented by the network device in the foregoing method embodiments may also be implemented by a component (e.g., a chip or a circuit) available to the network device.

The communication method provided by the embodiment of the present application is described in detail above with reference to fig. 1 to 8, and the communication device provided by the embodiment of the present application is described in detail below with reference to fig. 9 to 12.

Fig. 9 shows a schematic block diagram of a communication apparatus 900 provided in this embodiment of the application, where the apparatus 900 may correspond to the terminal device described in the foregoing method, and may also correspond to a chip or a component of the terminal device, and each module or unit in the apparatus 900 may be respectively configured to execute each action or processing procedure executed by the terminal device in the foregoing method, as shown in fig. 9, the communication apparatus 900 may include a transceiver unit 910 and a processing unit 920.

A transceiving unit 910, configured to receive a first message from a first network device or a second network device.

The transceiving unit 910 is further configured to receive PDCP PDUs from the first network device.

A processing unit 920, configured to determine a target parameter for processing the PDCP PDU according to the first message, where the target parameter is one of a first parameter corresponding to the first network device and a second parameter corresponding to the second network device, and the first parameter or the second parameter is used for processing the PDCP PDU.

The processing unit is further configured to process the PDCP PDU received from the first network device according to the target parameter, so as to obtain a PDCP SDU.

As an optional embodiment, the processing unit 920 is specifically configured to: and determining a target parameter for processing the PDCP PDU as the second parameter according to the first message, wherein the PDCP PDU received from the first network equipment is sent to the first network equipment by the second network equipment.

As an optional embodiment, the first message includes first indication information of bearer granularity, where the first indication information is used to assist the apparatus in determining the target parameter.

As an optional embodiment, the first indication information comprises a last PDCP sequence number for processing a PDCP PDU received from the first network device using the second parameter.

As an optional embodiment, the processing unit 920 is specifically configured to: if the PDCP sequence number of the PDCP PDU received from the first network equipment is less than or equal to the first PDCP sequence number, the target parameter is the second parameter; and/or the presence of a gas in the atmosphere,

As an optional embodiment, the first message is used to indicate that the PDCP PDU sent by the first network device from the second network device ends, and the processing unit 920 is specifically configured to:

before the transceiving unit receives a first message from the first network device or a second network device, the target parameter is the second parameter;

after the transceiver unit receives a first message from the first network device or a second network device, the target parameter is the first parameter.

As an optional embodiment, the first message is an RRC message, or a PDCP control PDU, or a DCI, or a MAC CE.

As an alternative embodiment, the processing unit 920 is further configured to: after the receiving unit receives a first message sent by the first network device or the second network device, the RRC connection with the second network device is released.

As an optional embodiment, the first parameter includes at least one of a key corresponding to the first network device, a header decompression context corresponding to the first network device, and an integrity verification parameter corresponding to the first network device; the second parameter includes at least one of a key corresponding to the second network device, a header decompression context corresponding to the second network device, and an integrity verification parameter corresponding to the second network device.

Optionally, the apparatus 900 may further include a storage unit, where the storage unit is configured to store codes or data, and the processing unit 920 may read the codes or data in the storage unit to implement corresponding operations.

The processing unit 920 in the above embodiments may be implemented by a processor or a processor-related circuit. The transceiving unit 910 may be implemented by a transceiver or transceiver-related circuitry. The transceiving unit 910 may also be referred to as a communication unit or a communication interface. The storage unit may be implemented by a memory.

It should be understood that, for the sake of brevity, detailed descriptions of the specific processes of the units in the apparatus 900 for executing the above corresponding steps are omitted here, please refer to the description of the method embodiments in conjunction with fig. 4 to fig. 8.

Fig. 10 shows a schematic block diagram of a communication apparatus 1000 according to an embodiment of the present application, where the apparatus 1000 may correspond to the first network device described in the foregoing method, and may also correspond to a chip or a component of the first network device, and each module or unit in the apparatus 1000 may be respectively configured to execute each action or process performed by the first network device in the foregoing method, as shown in fig. 10, and the communication apparatus 1000 may include a transceiver unit 1010.

A transceiving unit 1010, configured to send PDCP PDUs to a terminal device;

the transceiving unit 1010 is further configured to send a first message to the terminal device, where the first message is used to assist the terminal device in determining a target parameter, and the target parameter is used for the terminal device to process a PDCP PDU received from the apparatus, where the target parameter is one of a first parameter corresponding to the apparatus and a second parameter corresponding to the second network device, and the first parameter or the second parameter is used for the terminal device to process the PDCP PDU.

In a possible implementation manner, the apparatus 1000 includes a first sending unit and a second sending unit, where the first sending unit is configured to send a PDCP PDU to a terminal device; the second sending unit is configured to send a first message to the terminal device, where the first message is used to assist the terminal device in determining a target parameter, and the target parameter is used for the terminal device to process a PDCP PDU received from the apparatus, where the target parameter is one of a first parameter corresponding to the apparatus and a second parameter corresponding to the second network device.

As an optional embodiment, the transceiving unit 1010 is further configured to receive a PDCP PDU from a second network device before transmitting the PDCP PDU to the terminal device.

As an alternative embodiment, the transceiver 1010 is specifically configured to: and after all the PDCP PDUs from the second network equipment are sent to the terminal equipment, sending the first message to the terminal equipment, wherein the first message is used for indicating the end of the sending of the PDCP PDUs from the second network equipment.

As an alternative embodiment, the transceiving unit 1010 is further configured to:

and before sending the first message to the terminal equipment, receiving a second message from the second network equipment, wherein the second message is used for informing the device to distribute PDCP SN for the received PDCP service data units SDU without distributed PDCP sequence number SN.

As an optional embodiment, the first message includes first indication information of bearer granularity, where the first indication information is used by the terminal device to determine the target parameter.

As an optional embodiment, the first indication information includes a last PDCP sequence number for processing the PDCP PDU received from the apparatus using a second parameter corresponding to the second network device.

As an optional embodiment, the first parameter includes at least one of a key corresponding to the first network device, a header decompression context corresponding to the first network device, and an integrity verification parameter corresponding to the first network device; the second parameters include: at least one of a key corresponding to the second network device, a header decompression context corresponding to the second network device, and an integrity verification parameter corresponding to the second network device.

Optionally, the apparatus 1000 may further include a storage unit and a processing unit, where the storage unit is configured to store codes or data, and the processing unit may read the codes or data in the storage unit to implement corresponding operations.

The processing unit in the above embodiments may be implemented by a processor or processor-related circuits, and the transceiver unit 1010 may be implemented by a transceiver or transceiver-related circuits. The transceiving unit 1010 may also be referred to as a communication unit or a communication interface. The storage unit may be implemented by a memory.

It should be understood that, for the specific processes of the units in the apparatus 1000 to execute the corresponding steps described above, reference is made to the description of the method embodiment in conjunction with fig. 4 to fig. 8, and details are not repeated here for the sake of brevity.

Fig. 11 shows a schematic block diagram of a communication apparatus 1100 provided in this embodiment of the application, where the apparatus 1100 may correspond to the second network device described in the foregoing method, and may also correspond to a chip or a component of the second network device, and each module or unit in the apparatus 1100 may be respectively configured to execute each action or process performed by the second network device in the foregoing method, and as shown in fig. 11, the communication apparatus 1100 may include a processing unit 1110 and a transceiver unit 1120.

A processing unit 1110, configured to generate a first message, where the first message is used to assist a terminal device to determine a target parameter, where the target parameter is used for the terminal device to process a PDCP PDU received from the first network device, where the target parameter is one of a first parameter corresponding to the first network device and a second parameter corresponding to the second network device, and the first parameter or the second parameter is used for the terminal device to process the PDCP PDU;

a transceiving unit 1120, configured to send a first message to the terminal device.

As an alternative embodiment, the transceiver 1120 is further configured to: transmitting the PDCP PDU to the first network device after transmitting a Radio Resource Control (RRC) reconfiguration message to the terminal device.

As an alternative embodiment, the transceiver 1120 is further configured to: and sending a second message to the first network equipment, wherein the second message is used for informing the first network equipment of distributing PDCP SN for the received PDCP service data units SDU without distributed PDCP sequence number SN.

As an optional embodiment, the first indication information is used to indicate a last first PDCP sequence number for processing the PDCP PDU received from the first network device by using the corresponding second parameter of the apparatus.

Optionally, the apparatus 1100 may further include a storage unit, where the storage unit is configured to store codes or data, and the processing unit 1110 may read the codes or data in the storage unit to implement corresponding operations.

The processing unit 1110 may be implemented by a processor or processor-related circuits, and the transceiver unit 1120 may be implemented by a transceiver or transceiver-related circuits in the above embodiments. The transceiving unit 1120 may also be referred to as a communication unit or a communication interface. The storage unit may be implemented by a memory. It should be understood that for the specific processes of the units in the apparatus 1100 for executing the corresponding steps, reference is made to the description of the method embodiments in conjunction with fig. 4-8, and for brevity, no further description is given here.

The apparatus 900 of each of the above-mentioned schemes has a function of implementing corresponding steps executed by a terminal device in the above-mentioned method, the apparatus 1000 of each of the above-mentioned schemes has a function of implementing corresponding steps executed by a first network device in the above-mentioned method, and the apparatus 1100 of each of the above-mentioned schemes has a function of implementing corresponding steps executed by a second network device in the above-mentioned method; the functions can be realized by hardware or software, and the corresponding software can be executed by hardware. The hardware or software comprises one or more modules corresponding to the functions; for example, the sending unit may be replaced by a communication interface, the receiving unit may be replaced by a communication interface, and other units, such as the determining unit, may be replaced by a processor, to perform the transceiving operation and the related processing operation in each method embodiment, respectively. In an embodiment of the present application, a communication interface of an apparatus is used for the apparatus to communicate with other devices. For example, the communication interface may be a transmitter, a receiver, a transceiver, a circuit, a bus, a module, a pin, or other types of communication interfaces, and the embodiments of the present application are not limited thereto.

In particular implementations, the processor may be configured to perform, for example and without limitation, baseband-related processing, and the communication interface may be configured to perform, for example and without limitation, information exchange. The above devices may be respectively disposed on separate chips, or at least a part or all of the devices may be disposed on the same chip. For example, the processor may be further divided into an analog baseband processor and a digital baseband processor, wherein the analog baseband processor may be integrated with the communication interface on the same chip, and the digital baseband processor may be disposed on a separate chip. With the development of integrated circuit technology, more and more devices can be integrated on the same chip, for example, a digital baseband processor can be integrated with various application processors (such as but not limited to a graphics processor, a multimedia processor, etc.) on the same chip. Such a chip may be referred to as a System On Chip (SOC). Whether each device is separately located on a different chip or integrated on one or more chips often depends on the specific needs of the product design. The embodiment of the present application does not limit the specific implementation form of the above device.

It is understood that, for the processors referred to in the foregoing embodiments, the functions referred to in any design of the foregoing embodiments of the present application can be implemented by executing program instructions through a hardware platform having the processors and a communication interface, respectively, and based on this, as shown in fig. 12, the present application embodiment provides a schematic block diagram of an apparatus 1200 for transmitting information, where the apparatus 1200 includes: a processor 1210, a communication interface 1220, and a memory 1230. The processor 1210, the communication interface 1220 and the memory 1230 are coupled to communicate with each other, the memory 1230 is used for storing instructions, and the processor 1210 is used for executing the instructions stored in the memory 1230 to control the communication interface 1220 to transmit signals and/or receive signals. The coupling in the embodiments of the present application is an indirect coupling or a communication connection between devices, units or modules, and may be an electrical, mechanical or other form for information interaction between the devices, units or modules.

In a possible implementation manner, if the apparatus 1200 is a terminal device, the communication interface 1220 is configured to receive a first message from a first network device or a second network device; the communication interface 1220 is further configured to receive PDCP PDUs from the first network device; the processor 1210 is configured to determine a target parameter for processing the PDCP PDU according to the first message, where the target parameter is one of a first parameter corresponding to the first network device and a second parameter corresponding to the second network device, and the first parameter or the second parameter is used for processing the PDCP PDU; the processor 1210 is further configured to process the PDCP PDU received from the first network device according to the target parameter, so as to obtain a PDCP SDU.

In a possible implementation manner, if the apparatus 1200 is a first network device, the communication interface 1220 is configured to send a PDCP PDU to a terminal device; the communication interface 1220 is further configured to send a first message to the terminal device, where the first message is used to assist the terminal device in determining a target parameter, where the target parameter is used for the terminal device to process a PDCP PDU received from the apparatus, where the target parameter is one of a first parameter corresponding to the apparatus and a second parameter corresponding to the second network device, and the first parameter or the second parameter is used for the terminal device to process the PDCP PDU.

In a possible implementation manner, if the apparatus 1200 is a second network device, the processor 1210 is configured to generate a first message, where the first message is used to assist a terminal device to determine a target parameter, and the target parameter is used for the terminal device to process a PDCP PDU received from the first network device, where the target parameter is one of a first parameter corresponding to the first network device and a second parameter corresponding to the second network device, and the first parameter or the second parameter is used for the terminal device to process the PDCP PDU; communication interface 1220 is used to send a first message to the end device.

It should be understood that the apparatus in fig. 9 or the apparatus in fig. 10 or the apparatus in fig. 11 in this embodiment of the application may be implemented by the apparatus 1200 in fig. 12, and may be configured to perform various steps and/or flows corresponding to the terminal device, the first network device, and the second network device in the foregoing embodiment of the method.

In a possible design, an embodiment of the present application may further provide a communication system, which includes the first network device and the second network device, or includes the first network device, the second network device, and the terminal device. In one possible design, a communication system includes apparatus 1000 and apparatus 1100, or a communication system includes apparatus 900, apparatus 1000, and apparatus 1100.

It should be understood that the various design-related methods, procedures, operations, or steps described in the embodiments of this application can be implemented in a one-to-one correspondence manner through computer software, electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are executed in hardware or software depends on specific applications and design constraints of the technical solution, for example, aspects such as software and hardware decoupling with good generality and low cost are considered, and the functions can be implemented by adopting a mode of executing program instructions, or aspects such as system performance and reliability are considered, and special circuits are adopted to implement the functions. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.

According to the method provided by the embodiment of the present application, the present application further provides a computer program product, which includes: computer program code which, when run on a computer, causes the computer to perform the method in the above-described embodiments. The various embodiments in this application may also be combined with each other.

According to the method provided by the embodiment of the present application, the present application also provides a computer readable medium, the computer readable medium stores program code, and when the program code runs on a computer, the computer is caused to execute the method in the above embodiment.

In the embodiment of the present application, it should be noted that the above method embodiments of the present application may be applied to a processor, or may be implemented by a processor. The processor may be an integrated circuit chip having signal processing capabilities. In implementation, the steps of the above method embodiments may be performed by integrated logic circuits of hardware in a processor or instructions in the form of software. The processor may be a general purpose processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), an off-the-shelf programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic device, or discrete hardware components. The various methods, steps, and logic blocks disclosed in the embodiments of the present application may be implemented or performed. The general purpose processor may be a microprocessor or any conventional processor or the like.

It will be appreciated that the memory in the embodiments of the subject application can be either volatile memory or nonvolatile memory, or can include both volatile and nonvolatile memory. The non-volatile memory may be a read-only memory (ROM), a Programmable ROM (PROM), an Erasable PROM (EPROM), an electrically Erasable EPROM (EEPROM), or a flash memory. Volatile memory can be Random Access Memory (RAM), which acts as external cache memory. There are many different types of RAM, such as Static Random Access Memory (SRAM), dynamic Random Access Memory (DRAM), synchronous Dynamic Random Access Memory (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), synchlink DRAM (SLDRAM), and direct rambus RAM (DR RAM).

It should be understood that, in the various embodiments of the present application, the sequence numbers of the above-mentioned processes do not mean the execution sequence, and the execution sequence of each process should be determined by its function and inherent logic, and should not constitute any limitation to the implementation process of the embodiments of the present application.

The appearances of the phrases "first," "second," and the like in this application are only for purposes of distinguishing between different items and the phrases "first," "second," and the like do not by themselves limit the actual order or function of the items so modified. Any embodiment or design described herein as "exemplary," e.g., "optionally" or "in certain implementations" is not necessarily to be construed as preferred or advantageous over other embodiments or designs. Rather, use of these words is intended to present relevant concepts in a concrete fashion.

Various objects such as various messages/information/devices/network elements/systems/devices/operations/etc. that may appear in the present application are named, it is understood that these specific names do not constitute limitations on related objects, and the named names may vary with factors such as scenes, contexts, or usage habits, and the understanding of the technical meaning of the technical terms in the present application should be mainly determined from the functions and technical effects embodied/performed in the technical solutions.

The above embodiments may be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented in software, it may be implemented in whole or in part in the form of a computer program product. The computer program product may include one or more computer instructions. The procedures or functions described in accordance with the embodiments of the application are all or partially generated when the computer program instructions are loaded and executed on a computer. The computer may be a general purpose computer, a special purpose computer, a computer network, a network appliance, a terminal device 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 via wired (e.g., coaxial cable, fiber optic, digital Subscriber (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device, such as a server, a data center, etc., that incorporates one or more of the available media. The usable medium may be a magnetic medium (e.g., floppy disk, hard disk, magnetic disk), an optical medium (e.g., DVD), or a semiconductor medium (e.g., solid State Disk (SSD)), among others.

Those of ordinary skill in the art will appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the technical solution. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application.

It is clear to those skilled in the art that, for convenience and brevity of description, the specific working processes of the above-described systems, apparatuses and units may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again. In the embodiments of the present application, the embodiments may refer to each other, for example, methods and/or terms between the embodiments of the method may refer to each other, for example, functions and/or terms between the embodiments of the apparatus and the embodiments of the method may refer to each other, without logical contradiction.

In the several embodiments provided in the present application, it should be understood that the disclosed system, apparatus and method may be implemented in other ways. For example, the above-described apparatus embodiments are merely illustrative, and for example, the division of the units is only one logical division, and other divisions may be realized in practice, for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or units, and may be in an electrical, mechanical or other form.

The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one position, or may be distributed on multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.

In addition, functional units in the embodiments of the present application may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit.

The above description is only for the specific embodiments of the present application, but the scope of the present application is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present application, and shall be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A method of communication, comprising:

receiving a first message from the first network device or the second network device;

receiving a packet data convergence protocol, PDCP, protocol data unit, PDU, from the first network device;

determining a target parameter for processing the PDCP PDU according to the first message, where the target parameter is one of a first parameter corresponding to the first network device and a second parameter corresponding to the second network device, the first parameter or the second parameter is used for processing the PDCP PDU, the first message includes first indication information of bearer granularity, the first indication information is used for assisting a terminal device to determine the target parameter, and the first indication information includes a last first PDCP sequence number for processing a PDCP PDU received from the first network device by using the second parameter;

and processing the PDCP PDU received from the first network equipment according to the target parameter to obtain a PDCP Service Data Unit (SDU).

2. The communication method according to claim 1, wherein the determining the target parameter for processing the PDCP PDU according to the first message comprises:

and the PDCP PDU received from the first network equipment is sent to the first network equipment by the second network equipment, and the target parameter for processing the PDCP PDU is determined to be the second parameter according to the first message.

3. The communication method as claimed in claim 1, wherein the determining a target parameter for processing the PDCP PDU according to the first message comprises:

if a Packet Data Convergence Protocol (PDCP) sequence number of the PDCP PDU received from the first network equipment is less than or equal to the first PDCP sequence number, the target parameter is the second parameter; and/or the presence of a gas in the atmosphere,

4. The communication method according to claim 1, wherein the first message is used to indicate an end of the PDCP PDU sent by the first network device from the second network device, and the determining the target parameter for processing the PDCP PDU according to the first message comprises:

5. The communication method according to claim 1, wherein the first message comprises a radio resource control RRC message or a PDCP control PDU or a downlink control message DCI or a medium access control MAC control element CE.

6. The communication method according to claim 4, wherein after the receiving the first message sent by the first network device or the second network device, the method further comprises:

releasing the RRC connection with the second network device.

7. The communication method according to any one of claims 1 to 6, wherein the first parameter comprises at least one of a key corresponding to the first network device, a header decompression context corresponding to the first network device, and an integrity verification parameter corresponding to the first network device; the second parameter includes at least one of a key corresponding to the second network device, a header decompression context corresponding to the second network device, and an integrity verification parameter corresponding to the second network device.

8. A method of communication, comprising:

the first network equipment sends a packet data convergence protocol PDCP protocol data unit PDU to the terminal equipment;

the first network device sends a first message to the terminal device, where the first message is used to assist the terminal device in determining a target parameter, and the target parameter is used for the terminal device to process a PDCP PDU received from the first network device, where the target parameter is one of a first parameter corresponding to the first network device and a second parameter corresponding to a second network device, the first parameter or the second parameter is used for the terminal device to process the PDCP PDU, the first message includes first indication information of bearer granularity, the first indication information is used for the terminal device to determine the target parameter, and the first indication information includes a first PDCP sequence number of a last PDCP PDU processed by using the second parameter corresponding to the second network device.

9. The communication method according to claim 8, wherein before the first network device sends PDCP PDUs to a terminal device, the method further comprises:

the first network device receives the PDCP PDUs from a second network device.

10. The communication method according to claim 9, wherein the first network device sends a first message to the terminal device, including:

after the first network device sends all the PDCP PDUs from the second network device to the terminal device, the first network device sends the first message to the terminal device, and the first message is used for indicating that the sending of the PDCP PDUs from the second network device is finished.

11. The communication method according to claim 8, wherein before the first network device sends the first message to the terminal device, the method further comprises:

and the first network equipment receives a second message from the second network equipment, wherein the second message is used for informing the first network equipment of distributing the PDCP SN for the received PDCP service data units SDU without the distributed PDCP serial number SN.

12. The communication method according to claim 8, wherein the first message comprises a radio resource control RRC message or a PDCP control PDU or a downlink control message DCI or a medium access control MAC control element CE.

13. The communication method according to any one of claims 8 to 12, wherein the first parameter comprises at least one of a key corresponding to the first network device, a header decompression context corresponding to the first network device, and an integrity verification parameter corresponding to the first network device; the second parameter includes at least one of a key corresponding to the second network device, a header decompression context corresponding to the second network device, and an integrity verification parameter corresponding to the second network device.

14. A communications apparatus, characterized in that it comprises means for performing the method of any one of claims 1-7.

15. A communications apparatus, characterized in that it comprises means for performing the method of any of claims 8-13.

16. A computer-readable storage medium, characterized in that the computer-readable storage medium stores a computer program which, when executed on a computer, causes the computer to perform the method of any one of claims 1-13.