CN111328118B

CN111328118B - Transmission method and device

Info

Publication number: CN111328118B
Application number: CN202010117334.2A
Authority: CN
Inventors: 邓云; 顾祥新; 韩立锋
Original assignee: Spreadtrum Communications Shanghai Co Ltd
Current assignee: Spreadtrum Communications Shanghai Co Ltd
Priority date: 2020-02-25
Filing date: 2020-02-25
Publication date: 2021-12-21
Anticipated expiration: 2040-02-25
Also published as: CN114158099A; CN111328118A

Abstract

The embodiment of the application provides a transmission method and a device, the method is applied to terminal equipment, the terminal equipment is respectively connected with a main base station and a first auxiliary base station, and the method comprises the following steps: receiving a main and auxiliary cell updating instruction sent by a main base station, wherein the main and auxiliary cell updating instruction comprises an identifier of a second auxiliary base station; establishing a first protocol entity associated with the data radio bearer DRB and the second auxiliary base station according to the identifier of the second auxiliary base station; receiving first downlink data sent by a second auxiliary base station according to a first protocol entity, and receiving second downlink data sent by the first auxiliary base station according to a second protocol entity, wherein the second protocol entity is a protocol entity associated with the DRB and the first auxiliary base station; and combining the first downlink data and the second downlink data to obtain a packet data convergence protocol PDCP data packet corresponding to the DRB. According to the embodiment of the application, the DAPS switching under the double-connection scene can be realized, and the data transmission performance is improved.

Description

Transmission method and device

Technical Field

The embodiment of the invention relates to the technical field of communication, in particular to a transmission method and a transmission device.

Background

In a New air interface (NR) of 5G, a New Handover mechanism, i.e., Dual Active Protocol Stack Handover (DAPS HO), is introduced in a non-Dual connectivity scenario. For a Data Radio Bearer (DRB) using DAPS handover, a source base station needs to uniformly allocate sequence numbers to Packet Data Convergence Protocol (PDCP) Data packets, then send part of the PDCP Data packets and corresponding sequence numbers to a target base station, and then the target base station sends downlink Data to a terminal device during handover.

With the development of communication technology, systems in dual connection state are gradually widely used. In a dual-connection scenario, the terminal device can simultaneously utilize resources of two base stations to perform data transmission, which not only can improve data throughput rate, but also can improve mobility. However, when the secondary base station is handed over in the dual connectivity scenario, the DAPS handover cannot be realized, and it is difficult to realize the scheduling that the terminal device receives the source base station and the target base station simultaneously in the handover process.

Disclosure of Invention

The embodiment of the application provides a transmission method and a transmission device, which are used for solving the problem of data transmission in the switching process of an auxiliary base station in a dual-connection scene.

In a first aspect, an embodiment of the present application provides a transmission method, which is applied to a terminal device, where the terminal device is connected to a main base station and a first secondary base station, and the method includes:

receiving a main and auxiliary cell updating instruction sent by a main base station, wherein the main and auxiliary cell updating instruction comprises an identifier of a second auxiliary base station;

establishing a first protocol entity associated with a Data Radio Bearer (DRB) and the second auxiliary base station according to the identifier of the second auxiliary base station;

receiving first downlink data sent by a second auxiliary base station according to the first protocol entity, and receiving second downlink data sent by the first auxiliary base station according to a second protocol entity, wherein the second protocol entity is a protocol entity associated with the DRB and the first auxiliary base station;

and combining the first downlink data and the second downlink data to obtain a packet data convergence protocol PDCP data packet corresponding to the DRB.

In one possible implementation manner, the first downlink data includes first PDCP data packets and a sequence number of each first PDCP data packet; the second downlink data includes second PDCP data packets and a sequence number of each second PDCP data packet.

In a possible implementation manner, merging the first downlink data and the second downlink data to obtain a PDCP data packet corresponding to the DRB includes:

and according to the sequence number of each first PDCP data packet and the sequence number of each second PDCP data packet, performing de-duplication processing and sequencing processing on the first PDCP data packets and the second PDCP data packets to obtain the PDCP data packets.

In one possible implementation, the method further includes:

and monitoring the state of a wireless link between the first secondary base station and the first secondary base station.

In a possible implementation manner, the receiving, according to the second protocol entity, second downlink data sent by the first secondary base station includes:

and when the wireless link state between the first auxiliary base station and the first auxiliary base station is determined to be normal according to the wireless link state between the first auxiliary base station and the first auxiliary base station, receiving second downlink data sent by the first auxiliary base station according to the second protocol entity.

when the wireless link state between the first auxiliary base station and the first auxiliary base station is determined to be abnormal according to the wireless link state between the first auxiliary base station and the first auxiliary base station, transmitting first auxiliary base station link abnormal information to the main base station, wherein the link abnormal information comprises the information of the first auxiliary base station;

and receiving second downlink data sent by the second secondary base station, wherein the second downlink data is sent to the second secondary base station by the first secondary base station through the main base station.

In a possible implementation manner, the primary and secondary cell update instruction further includes a separate bearer, and the method further includes:

deleting a third protocol entity associated with the separation bearer and the first secondary base station, and establishing a fourth protocol entity associated with the separation bearer and the second secondary base station;

and after the random access with the second secondary base station is completed, receiving downlink data corresponding to the separation bearer from the second secondary base station according to the fourth protocol entity.

In one possible implementation, after completing random access with the second secondary base station, the method further includes:

and receiving indication information sent by the second auxiliary base station, and disconnecting the first auxiliary base station according to the indication information.

In a second aspect, an embodiment of the present application provides a transmission apparatus, including:

the first receiving module is used for receiving a main and auxiliary cell updating instruction sent by a main base station, wherein the main and auxiliary cell updating instruction comprises an identifier of a second auxiliary base station;

a first processing module, configured to establish a first protocol entity associated with a data radio bearer DRB and the second secondary base station according to the identifier of the second secondary base station;

a second receiving module, configured to receive, according to the first protocol entity, first downlink data sent by a second secondary base station, and receive, according to a second protocol entity, second downlink data sent by a first secondary base station, where the second protocol entity is a protocol entity associated with the DRB and the first secondary base station;

and the second processing module is configured to combine the first downlink data and the second downlink data to obtain a packet data convergence protocol PDCP data packet corresponding to the DRB.

In a possible implementation manner, the second processing module is specifically configured to:

In one possible implementation manner, the first processing module is further configured to:

In a possible implementation manner, the second receiving module is specifically configured to:

In a possible implementation manner, the primary and secondary cell update instruction further includes a separate bearer, and the second processing module is further configured to:

In a possible implementation manner, the second receiving module is further configured to:

In a third aspect, an embodiment of the present application provides a terminal device, including: at least one processor and memory;

the memory stores computer-executable instructions;

the at least one processor executing the computer-executable instructions stored by the memory causes the at least one processor to perform the transmission method of any of the first aspects.

In a fourth aspect, an embodiment of the present application provides a computer-readable storage medium, where computer-executable instructions are stored, and when a processor executes the computer-executable instructions, the transmission method according to any one of the first aspect is implemented.

The transmission method and the transmission device provided by the embodiment of the application are applied to a dual-connection scene, when the secondary base station needs to be switched, the update instruction of the primary and secondary cells sent by the primary base station is firstly received, the update instruction of the primary and secondary cells comprises the identification of the second secondary base station, and the terminal equipment can know which secondary base station needs to be accessed according to the identification of the second secondary base station. And for the DRB configured with the DAPS handover, the terminal equipment establishes a first protocol entity associated with the DRB and the second auxiliary base station according to the identifier of the second auxiliary base station, receives second downlink data sent by the first auxiliary base station according to a second protocol entity associated with the DRB and the first auxiliary base station, and combines the first downlink data and the second downlink data to obtain a corresponding complete and ordered PDCP data packet. The method provided by the embodiment of the application can realize the DAPS switching under the dual-connection scene, so that the terminal equipment can simultaneously receive the downlink scheduling of the first auxiliary base station and the second auxiliary base station in the switching process of the auxiliary base stations.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

Fig. 1 is a schematic diagram of a DAPS handover provided in an embodiment of the present application;

fig. 2 is a schematic diagram of a dual connection scenario provided in an embodiment of the present application;

fig. 3 is a schematic view of an application scenario provided in an embodiment of the present application;

fig. 4 is a schematic flowchart of a transmission method according to an embodiment of the present application;

fig. 5 is a signaling diagram of a secondary base station handover provided in an embodiment of the present application;

fig. 6 is a schematic diagram of determining a second secondary base station according to an embodiment of the present application;

fig. 7 is a schematic diagram of a UE processing procedure provided in an embodiment of the present application;

fig. 8 is a schematic diagram of data forwarding provided in the embodiment of the present application;

fig. 9 is a schematic structural diagram of a transmission device according to an embodiment of the present application;

fig. 10 is a schematic diagram of a hardware structure of a terminal device according to an embodiment of the present application.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

First, the concept related to the present application will be explained.

The terminal equipment: the device can be a device which comprises a wireless transceiving function and can be matched with network equipment to provide communication services for users. In particular, a terminal device may refer to a User Equipment (UE), an access terminal, a subscriber unit, a subscriber station, a mobile station, a remote terminal, a mobile device, a User terminal, a wireless communication device, a User agent, or a User Equipment. For example, the terminal device may 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 capability, a computing device or other processing device connected to a Wireless modem, an in-vehicle device, a wearable device, a terminal device in a future 5G network or a network after 5G, and so on.

Radio Link Control (RLC) entity: each logical channel of the terminal equipment corresponds to one RLC entity. The RLC entities may be configured in different RLC modes, which may be any one of three modes: transparent Mode (TM), Unacknowledged Mode (UM), Acknowledged Mode (AM). The three modes are explained below:

a transparent transmission mode: an RLC entity configured in a transparent mode, in which the TM RLC entity provides only a transparent function of data, may also be referred to as a TM RLC entity.

Non-acknowledgement mode: the RLC entity configured in the unacknowledged mode, in which the UM RLC entity may provide all RLC functions except for retransmission, re-segmentation, duplicate packet detection, protocol error detection, may also be referred to as the UM RLC entity, and thus, the reliability of the transmission service provided by the UM RLC entity is poor.

Confirming mode: the RLC entity configured in the acknowledged mode may also be referred to as an AM RLC entity, and the AM RLC entity may provide all RLC functions, and since the AM RLC entity may provide functions of error detection, retransmission, and the like, the reliability of the transmission service provided by the AM RLC entity is high.

The base station may be a next generation base station (gNB) or a next generation evolved node b (ng-eNB). The gNB provides a user plane function and a control plane function of a new radio interface (NR) for the UE, and the ng-eNB provides a user plane function and a control plane function of an evolved universal terrestrial radio access (E-UTRA) for the UE, where it should be noted that the gNB and the ng-eNB are only names used for representing a base station supporting a 5G network system and do not have a limiting meaning. The base station may also be a Base Transceiver Station (BTS) in a Global System for Mobile Communications (GSM) GSM System or a code division multiple access (cdma) System, or an evolved node B (eNB or eNodeB) in an LTE System.

Fig. 1 is a schematic diagram of a DAPS handover provided in an embodiment of the present application, and as shown in fig. 1, the DAPS handover includes a terminal device 10, a source base station 11, and a target base station 12, where the terminal device 10 is connected to the source base station 11 and exchanges data. When the location of the terminal apparatus 10 changes, which may involve handover of base stations, the terminal apparatus 10 transitions from the state of initially establishing connection with the source base station 11 to establishing connection with the target base station 12, and after establishing connection with the target base station 12, disconnects from the source base station 11.

After the connection is established between the terminal device 10 and the source base station 11, the terminal device 10 and the source base station 11 may exchange uplink data and downlink data. When the terminal device 10 needs to perform a base station handover, that is, when the terminal device 10 is handed over from the cell managed by the source base station 11 to the cell managed by the target base station, the terminal device needs to disconnect the connection with the source base station 11 and establish a connection with the target base station 12.

In NR Release 16, DAPS handover is introduced. For downlink data transmission, for a DRB applying DAPS handover, the source base station 11 needs to uniformly allocate PDCP sequence numbers to PDCP data packets, then send part of the PDCP data packets and corresponding sequence numbers to the target base station 12, and send part of the PDCP data packets and corresponding sequence numbers to the terminal device 10. The PDCP packet sent by the source base station 11 to the terminal device 10 is processed by using a header compression and security algorithm at the source base station (first performing header compression and then performing encryption), and then sent to the terminal device 10 by the source base station 11. After receiving a part of PDCP data packets and corresponding sequence numbers sent by the source base station, the target base station 12 processes the part of PDCP data packets by using the security algorithm and the header compression algorithm of the target base station side, and then sends the encrypted PDCP data packets to the terminal device 10. The method for encrypting the PDCP data packet by the source base station 11 and the method for encrypting the PDCP data packet by the target base station 12 are relatively independent. After receiving the PDCP data packets sent by the source base station 11 and the target base station 12, the terminal device 10 applies the corresponding header compression algorithm to Decompress according to the different sources of the PDCP data packets and decrypts according to the security algorithm (first performing decryption and then performing decompression), and after decryption, obtains complete and ordered PDCP data packets by using a common sorting function according to the sequence numbers of the PDCP data packets, thereby implementing secure transmission of the PDCP data packets.

For uplink data transmission, for DRBs applying DAPS handover, during the handover, the terminal device 10 may uniformly allocate sequence numbers to PDCP data packets, then send part of the data packets to the source base station 11 through a source link with the source base station 11, and send part of the data packets to the target base station 12 through a target link with the target base station 12. Similarly, the terminal device 10 applies different security algorithms and header compression algorithms, which are independent of each other, to the PDCP data packet transmitted to the source base station 11 and the PDCP data packet transmitted to the target base station 12 for different transmission targets.

In the above manner, in the course of DAPS handover, the terminal device 10 may receive the downlink scheduling of the source base station 11 and the target base station 12 at the same time, until the target base station 12 instructs the terminal device to release the configuration of the source base station 11, and the terminal device 10 stops receiving the downlink scheduling from the source base station 11 and disconnects from the source base station 11.

In the switching of the base station and the cell, the terminal equipment can be ensured to simultaneously receive the scheduling information of the source base station and the target base station by means of DAPS switching, and the occurrence of data transmission interruption is avoided.

At present, DAPS handover is mainly applied to a non-dual connectivity scenario, where a dual connectivity scenario refers to a terminal device being in a connected state with two base stations or network devices. The dual connectivity may be of different types for different types of two base stations or network devices.

Fig. 2 is a schematic diagram of a dual connectivity scenario provided in the embodiment of the present application, and as shown in fig. 2, the dual connectivity scenario includes a terminal device 20, a base station 21, and a base station 22, where the terminal device 20 establishes connectivity with the base station 21 and the base station 22, respectively. In a dual-connection scenario, one of two base stations establishing a connection with a terminal device is a primary base station, and the other is a secondary base station.

The dual connectivity may be of different types depending on the system to which the base station corresponds. For example, when the primary base station and the secondary base station are both base stations in an LTE system, the dual connection type is LTE dual connection; when the main base station and the auxiliary base station are both base stations under an NR system, the double connection type is NR double connection; when one of the two base stations is a base station under an LTE system, and the other one is a base station under an NR system, the dual connection type is dual connection of LTE and NR. For dual connectivity of LTE and NR types, it can be further divided into: the LTE base station is used as a main base station of the terminal equipment, and the NR base station is used as an auxiliary base station of the terminal equipment; the NR base station is used as a main base station of the terminal equipment, and the LTE base station is used as an auxiliary base station of the terminal equipment; the LTE base station connected with the 5G core network is used as a main base station of the terminal equipment, and the NR base station is used as an auxiliary base station of the terminal equipment.

After LTE-NR dual connectivity is configured, the SgNB side (i.e., the secondary base station side) may also establish a Signaling Radio Bearer (SRB) with the UE. In this case, the UE has Radio Resource Control (RRC) connection (MCG RRC) on the primary base station side, and also has RRC connection (SCG RRC) on the secondary base station side. When the secondary base station needs to modify the radio parameter configuration of the secondary base station side for the UE, the parameter reconfiguration can be directly realized by the interaction of the SCG RRC and the UE.

The UE may be configured with Carrier Aggregation (CA) at the master base station (MeNB) and the secondary base station (SgNB), respectively. Specifically, the serving carrier configured for the UE in the MeNB is a Master Cell Group (MCG), and the serving carrier configured for the UE in the SgNB is a Secondary Cell Group (SCG). For the UE establishing dual connectivity, the MeNB side has a primary cell (PCell), the UE receives system messages, paging messages and the like in the cell, and the primary cell (PCell) is configured with a Physical Uplink Control Channel (PUCCH); on the secondary base station side, there is a primary and secondary cell (PSCell), which is also configured with PUCCH.

In the dual connection technique, one terminal can be simultaneously connected to two base stations connected through a non-ideal backward backhaul for data communication. The terminal equipment can simultaneously utilize the resources of the two base stations to carry out data transmission, thereby not only improving the data throughput rate, but also improving the mobility.

With the wide application of the dual connectivity scenario, the base station handover in the dual connectivity scenario also becomes an urgent problem to be solved. The following describes the base station handover in the dual connectivity scenario with reference to fig. 3.

Fig. 3 is a schematic view of an application scenario provided in the embodiment of the present application, and as shown in fig. 3, the application scenario includes a terminal device 30, a first auxiliary base station 31, a second auxiliary base station 32, and a main base station 33. When the base station switching is not performed, the terminal device 30 is in a dual connection state, and establishes connections with the first auxiliary base station 31 and the main base station 33, respectively. When the terminal device 30 needs to perform handover of the secondary base station (or called update of the secondary base station), for example, the terminal device 30 moves the location, at this time, the terminal device 30 uploads a measurement report, and the first secondary base station 31 determines to handover the secondary base station to the second secondary base station 32 according to the measurement report uploaded by the terminal device 30.

The embodiment of the application provides a method for performing handover of an auxiliary base station (or called as updating of the auxiliary base station) by using a DAPS handover in a dual-connection scenario, which can ensure that terminal equipment can simultaneously receive scheduling of a source auxiliary base station and a target auxiliary base station and can transmit data between the source auxiliary base station and the target auxiliary base station.

Fig. 4 is a schematic flowchart of a transmission method provided in an embodiment of the present application, where the method is applied to a terminal device, and the terminal device is connected to a main base station and a first secondary base station, as shown in fig. 2, and includes:

and S41, receiving a primary and secondary cell update instruction sent by the primary base station, wherein the primary and secondary cell update instruction comprises an identifier of the second secondary base station.

The embodiment of the application is applied to a dual-connection scene, and before the switching of the secondary base station, the terminal equipment is respectively connected with the main base station and the first secondary base station. When the secondary base station needs to be updated, the terminal device receives a primary and secondary cell update instruction sent by the primary base station, where the primary and secondary cell update instruction includes an identifier of the second secondary base station, and is used to indicate that the terminal device can start switching the secondary base stations, and switch from the first secondary base station to the second secondary base station. It should be noted that the update instruction of the primary and secondary cells may include an identifier of a cell under the jurisdiction of the second secondary base station, and the identifier of the cell under the jurisdiction indirectly indicates the identifier of the second secondary base station.

S42, according to the second auxiliary base station mark, establishing data wireless bearing DRB and the second auxiliary base station related first protocol entity.

The process of the secondary base station handover requires a certain time, and during this time, the terminal device still needs to perform data transmission with the first secondary base station. In the embodiment of the present application, the second secondary base station configures DAPS handover. For a DRB configured with DAPS handover, the terminal device needs to establish a first protocol entity associated with the second secondary base station. Specifically, the terminal device establishes a first protocol entity associated with the DRB and the second secondary base station according to the identifier of the second secondary base station, where the first protocol entity may be, for example, an RLC entity and an MAC entity. Because the terminal equipment is accessed to the primary and secondary cells governed by the second secondary base station, the terminal equipment establishes a first protocol entity associated with the DRB and the target primary and secondary cells.

S43, receiving, according to the first protocol entity, first downlink data sent by a second secondary base station, and receiving, according to a second protocol entity, second downlink data sent by the first secondary base station, where the second protocol entity is a protocol entity associated with the DRB and the first secondary base station.

When the terminal device is in a dual-connection state, a second protocol entity associated with the DRB and the first secondary base station is established between the terminal device and the first secondary base station, and after the first protocol entity is established by the terminal device, the terminal device can receive the data packet of the DRB from the first secondary base station and the data packet of the DRB from the second secondary base station simultaneously in the process of switching the secondary base stations.

Specifically, the terminal device receives first downlink data sent by the second secondary base station according to the first protocol entity, and receives second downlink data sent by the first secondary base station according to the second protocol entity. The first downlink data includes a partial PDCP data packet and a corresponding sequence number, and the second downlink data also includes a partial PDCP data packet and a corresponding sequence number.

Optionally, the second downlink data sent by the first secondary base station may adopt an encryption algorithm of the first secondary base station side, the first downlink data sent by the second secondary base station may adopt an encryption algorithm of the second secondary base station side, and the first secondary base station and the second secondary base station may adopt respective independent encryption algorithms.

And S44, merging the first downlink data and the second downlink data to obtain a packet data convergence protocol PDCP data packet corresponding to the DRB.

And after receiving the first downlink data and the second downlink data, the terminal equipment obtains a merged PDCP data packet according to the first downlink data and the second downlink data.

Optionally, after the first auxiliary base station encrypts the second downlink data, the second auxiliary base station encrypts the first downlink data, and after receiving the first downlink data and the second downlink data, the terminal device decrypts the first downlink data by using the decryption method of the second auxiliary base station side, decrypts the second downlink data by using the decryption method of the first auxiliary base station side, and then obtains the corresponding PDCP data packet according to the decrypted first downlink data and the decrypted second downlink data. After the first downlink data and the second downlink data are obtained, the terminal device may obtain a complete and ordered PDCP data packet according to respective corresponding sequence numbers of the PDCP data packet.

The transmission method provided by the embodiment of the application is applied to terminal equipment, the terminal equipment is respectively connected with a main base station and a first auxiliary base station, when the auxiliary base station needs to be switched, a main and auxiliary cell updating instruction sent by the main base station is firstly received, the main and auxiliary cell updating instruction comprises an identifier of a second auxiliary base station, and the terminal equipment can know which auxiliary base station needs to be accessed according to the identifier of the second auxiliary base station. And for the DRB configured with the DAPS handover, the terminal equipment establishes a first protocol entity associated with the DRB and the second auxiliary base station according to the identifier of the second auxiliary base station, receives second downlink data sent by the first auxiliary base station according to a second protocol entity associated with the DRB and the first auxiliary base station, and combines the first downlink data and the second downlink data to obtain a corresponding complete and ordered PDCP data packet. The method provided by the embodiment of the application can realize the DAPS switching under the dual-connection scene, so that the terminal equipment can simultaneously receive the downlink scheduling of the first auxiliary base station and the second auxiliary base station in the switching process of the auxiliary base stations.

The scheme of the present application will be explained by specific examples.

Fig. 5 is a signaling diagram of a secondary base station handover provided in an embodiment of the present application, and as shown in fig. 5, the signaling diagram includes:

s501, the UE establishes double connection.

The scheme of the embodiment of the application is applied to a dual-connection scenario, wherein the UE establishes connection with the main base station and the first auxiliary base station respectively. The flow of establishing a dual connection may refer to the protocol TS 37.340. After the UE establishes the dual connectivity, the primary base station and the first secondary base station may provide communication services and scheduling for the UE at the same time.

Further, the primary base station and the first secondary base station may configure a measurement task for the UE, and the UE performs measurement according to the measurement task and then uploads a measurement report when a reporting condition is met. And if the measurement task is configured by the main base station, reporting the corresponding measurement report to the main base station by the UE, and if the measurement task is configured by the first auxiliary base station, reporting the corresponding measurement report to the first auxiliary base station by the UE.

S502, the UE sends a measurement report to the first secondary base station.

When the handover of the secondary base station needs to be performed, the UE sends a measurement report to the first secondary base station. Specifically, the UE may measure cells served by a plurality of secondary base stations according to the measurement task of the first secondary base station, and then the first secondary base station determines a second secondary base station to be handed over according to the measurement result of the UE.

S503, the first secondary base station receives a measurement report from the UE.

After the UE sends the measurement report to the first secondary base station, the first secondary base station receives the measurement report sent by the UE. In the measurement report sent by the UE, the measurement result information of the cells served by the multiple secondary base stations may be included, and the first secondary base station needs to select one of the cells as a target secondary base station to which the UE is to establish a connection.

Fig. 6 is a schematic diagram of determining a second secondary base station according to the embodiment of the present application, and as shown in fig. 6, the terminal device 60 is in a dual connectivity state, where the secondary base station corresponding to the terminal device 60 is a first secondary base station 61, and a main base station corresponding to the terminal device 60 is not shown in fig. 6. The first auxiliary base station 61 may configure the terminal device 60 with a measurement task, and the terminal device performs the measurement task according to the first auxiliary base station 61 and then uploads a measurement report to the first auxiliary base station 61. In fig. 6, the measurement report uploaded by the terminal device 60 may include measurement result information of cells served by the

base stations

62, 63, and 64, and then the first secondary base station 61 selects one of them as the second secondary base station, and instructs the terminal device 60 to attempt to establish a connection with the second secondary base station in a subsequent process, for example, in fig. 6, the base station 62 may be used as the second secondary base station.

And S504, the first auxiliary base station determines to carry out the switching of the main and auxiliary cells.

And after determining the second auxiliary base station for switching, the first auxiliary base station determines to switch the main and auxiliary cells.

And S505, the first auxiliary base station sends a main and auxiliary cell updating request to the main base station.

S506, the primary base station receives the primary and secondary cell update request.

S507, the primary base station sends a primary and secondary cell update request to the second secondary base station.

After determining the second secondary base station, the first secondary base station sends a primary and secondary cell update request to the second secondary base station through forwarding of the primary base station. Specifically, the first secondary base station first sends a primary and secondary cell update request to the primary base station, and the primary base station sends the primary and secondary cell update request to the second secondary base station after receiving the primary and secondary cell update request sent by the first secondary base station. The primary and secondary cell update request includes a UE context, such as a data radio bearer currently established by the UE, capability information of the UE, and radio parameters allocated by the first secondary base station to the UE.

And S508, the second auxiliary base station receives the updating request of the main and auxiliary cells and allocates wireless resources for the UE according to the updating request of the main and auxiliary cells.

After receiving the primary and secondary cell update request sent by the primary base station, the second secondary base station can judge the load state of the second secondary base station to determine whether to allow the UE to access. If the load status of the second secondary base station allows the UE to access, the second secondary base station allocates necessary radio resources for the UE.

S509, the second secondary base station sends the primary and secondary cell update request acknowledgement information to the primary base station.

After the second secondary base station allocates the radio resource to the UE, the second secondary base station sends the update request acknowledgement information of the primary and secondary cells to the primary base station, so as to feed back the update request acknowledgement to the primary base station. In this embodiment, the second secondary base station configures the DAPS handover for the UE, and the second secondary base station may configure the DAPS handover for one or more DRBs established by the UE.

S510, the main base station sends a main and auxiliary cell updating instruction to the UE.

And after receiving the update request confirmation information of the main and auxiliary cells sent by the second auxiliary base station, the main base station sends the update request confirmation information to the UE through RRC signaling, wherein the RRC signaling is a main and auxiliary cell update instruction.

S511, the UE receives the updating command of the main and auxiliary cells sent by the main base station, and performs RRC reconfiguration according to the updating command of the main and auxiliary cells.

After receiving the update instruction of the primary and secondary cells sent by the primary base station, the UE learns that the second secondary base station configures the DAPS handover, and the UE needs to establish a branch of the DRB associated with the second secondary base station, so that the UE receives the data packet of the DRB from the first secondary base station and the second secondary base station simultaneously in the handover process.

S512, the UE sends RRC reconfiguration complete information to the primary base station.

S513, the primary base station sends the primary and secondary cell update confirmation information to the first secondary base station.

And S514, the main base station sends the reconfiguration completion information of the main and auxiliary cells to the second auxiliary base station.

S515, when the DRB for DAPS handover is configured, the UE continues to monitor the radio link state of the first auxiliary base station, establishes a first protocol entity associated with the DRB and the second auxiliary base station, receives first downlink data sent by the second auxiliary base station according to the first protocol entity, and receives second downlink data sent by the auxiliary base station according to the second protocol entity.

The UE monitors the state of a wireless link between the UE and the first auxiliary base station, and receives second downlink data sent by the first auxiliary base station according to a second protocol entity when the state of the wireless link between the UE and the first auxiliary base station is determined to be normal according to the state of the wireless link between the UE and the first auxiliary base station. When the state of the wireless link between the first auxiliary base station and the first auxiliary base station is determined to be abnormal according to the wireless link information between the first auxiliary base station and the first auxiliary base station, the transmission of the downlink data is realized through the wireless link between the second auxiliary base station and the second auxiliary base station. Specifically, the UE sends link abnormal information or link failure information of the first secondary base station to the primary base station, where the link abnormal information includes an identifier of the first secondary base station or information indicating only the source secondary base station; and then, receiving a second downlink data packet sent by the second secondary base station, wherein the second downlink data packet is sent by the first secondary base station to the second secondary base station through the main base station. The radio link between the UE and the first secondary base station may be abnormal in one or more of the following three situations, the first situation is that the timer T310 is overtime, the second situation is that the RLC layer reaches the maximum retransmission number, and the third situation is that the random access is abnormal.

For the terminal equipment configured with dual connectivity, two data radio bearers can be configured at the secondary base station side, one is SCG DRB, and the DRB uses the radio resources at the secondary base station side for data transmission; the other is Split bearer (Split DRB) which performs data transmission using radio resources on the primary base station side and radio resources on the secondary base station side. Because the Split DRB can use the wireless resource of the primary base station side to perform uplink and downlink data transmission in the secondary base station update process, it is not necessary to adopt a DAPS handover mechanism for the Split DRB to achieve 0ms handover delay; meanwhile, considering that the complexity of the implementation of the Split DRB by means of DAPS handover is very high, and in order to avoid too high design cost of the terminal device, the present application provides a simple processing mechanism, where the terminal device is configured not to configure the detached bearer included in the update instruction of the primary and secondary cells as a default for the detached bearer to be the DAPS handover. And the terminal equipment deletes the third protocol entity associated with the separation bearer and the first auxiliary base station, and establishes the fourth protocol entity associated with the separation bearer and the second auxiliary base station. After the terminal device accesses the second secondary base station, for example, after the terminal device completes random access with the second secondary base station, the terminal device may receive downlink data corresponding to the split bearer from the second secondary base station according to the fourth protocol entity. By adopting a default processing mechanism, the configuration signaling of the network side can be reduced.

The following processing procedure after receiving the DAPS handover command for the UE is described with reference to fig. 7.

Fig. 7 is a schematic diagram of a UE processing procedure provided in the embodiment of the present application, and as shown in fig. 7, after receiving the DAPS handover command, the UE continues the Radio Link control layer protocol at the first secondary base station side, receives scheduling information from the first secondary base station side, where the scheduling information includes receiving downlink data and receiving an uplink grant to execute uplink transmission, and continues Radio Link Monitor (RLM) at the first secondary base station side. While the UE starts performing random access at the second secondary base station.

Specifically, the method for configuring the data radio bearer for DAPS handover includes the following steps:

s711, the UE reconfigures the PDCP of the bearer;

s712, newly establishing an RLC entity and a Medium Access Control (MAC) entity, where one PDCP entity is associated with two RLC entities;

s713, continuously receiving the downlink data of the first auxiliary base station side;

s714, performing random access at the second secondary base station side;

s715, continuously detecting the state of a wireless link with the first auxiliary base station side;

s716, if the detection finds that the radio link with the first secondary base station side fails, notifying the primary base station that the radio link with the first secondary base station side fails.

The UE stops receiving downlink data and signaling from the first secondary base station, and at this time, the UE may report the SCG failure to the main base station because the UE has an available radio link to maintain RRC connection with the main base station.

When the master base station receives the SCG Failure reported by the UE, and learns that the radio link at the source-secondary base station (i.e., the first secondary base station) side fails, the master base station needs to send SCG Failure information to the source-secondary base station through an Xn interface at this time, and the source-secondary base station stops scheduling the UE after receiving the information, and for the PDCP Data packet originally expected to be sent from the local side to the UE, the source-secondary base station immediately performs Data forwarding (Data forwarding), for example, the master base station sends the PDCP Data packet to the target-secondary base station, and for each DRB configured with DAPS, the downlink Data packet starts from the Data packet that the first UE has not confirmed to receive yet, and the source-secondary base station sends the Data packets to the target-secondary base station together with the PDCP sequence number (PDCP SN) corresponding to each Data packet, regardless of whether the DRB is AM or UM. By the method, the source-auxiliary base station can terminate the allocation of the wireless resources to the UE in time, so that the wireless resources can be effectively saved; meanwhile, downlink data to be transmitted can be transferred to the target auxiliary base station in time, the target auxiliary base station is facilitated to send the data to the UE in time, and data transmission delay is reduced.

In the process that the UE accesses the second auxiliary base station, the random access initiated by the UE may not be successfully accessed to the second auxiliary base station before the timer T304 times out, at this time, the UE determines that the radio link at the side of the second auxiliary base station fails, that is, the timer T304 times out, at this time, the UE needs to report the SCG failure to the main base station, and in order to make the main base station recognize which side of the auxiliary base station has a problem, the UE needs to explicitly indicate that the radio link of the target auxiliary base station fails, considering that the UE has an active auxiliary base station (that is, the first auxiliary base station) and a target auxiliary base station (that is, the second auxiliary base station) at the side of the auxiliary base station at this time. When the main base station receives the SCG Failure reported by the UE and learns that the wireless link at the side of the target auxiliary base station (namely, the second auxiliary base station) fails, the main base station can inform the source auxiliary base station to terminate the updating of the main and auxiliary cells, or can directly release the auxiliary base station.

And stopping the RLM at the side of the first secondary base station after the UE and the second secondary base station are successfully accessed randomly. Specifically, the method comprises the following steps:

s721, switching the uplink PDCP transmission of the UE;

s722, continuing HARQ transmission and retransmission with a Hybrid automatic repeat reQuest (Hybrid automatic repeat reQuest) at the first secondary base station side;

s723, receiving downlink data of two sides at the same time, and executing public sorting;

after the random access with the second secondary base station is successful, the second secondary base station may notify the UE to release the configuration on the first secondary base station side. Specifically, the method comprises the following steps:

s731, the second secondary base station informs the UE to recover the PDCP entity of the bearer for implementing the DAPS handover;

s732, the second secondary base station notifies the UE to release the RLC and MAC configuration of the first secondary base station.

Alternatively, step S731 and step S732 may be performed simultaneously.

When the UE is successfully accessed to the second secondary base station side at random, the UE does not execute the radio link detection of the first secondary base station side any more. But the UE continues to receive scheduling from the first secondary base station side, including receiving downlink data and performing uplink transmission according to the uplink grant. And until the second auxiliary base station side informs the UE to release the first auxiliary base station through RRC signaling, the UE releases all the configurations of the first auxiliary base station side and stops data transmission with the first auxiliary base station.

Fig. 8 is a schematic diagram of data forwarding provided in the embodiment of the present application, as shown in fig. 8, including a UE80 (see reference numeral 80 in fig. 8), a first secondary base station 81, a second secondary base station 82, and a main base station 83. Initially, the UE80 is in dual connectivity state with its corresponding primary and secondary base stations being the primary base station 83 and the first secondary base station 81, respectively. In performing the secondary base station update, the UE needs to be handed over from the first secondary base station to the second secondary base station 82.

After the UE80 receives the primary-secondary cell update command, the UE80 continues to perform radio link detection on the first secondary base station side while the UE starts performing random access on the second secondary base station side.

If the UE80 finds that the radio link with the first secondary base station side fails, the UE80 stops receiving downlink data and signaling from the first secondary base station 81, and at this time, the UE80 still has a radio link to maintain RRC connection with the primary base station 83, so the UE80 may report information about the radio link abnormality with the first secondary base station to the primary base station 83.

Since the UE80 now involves the first secondary base station 81 and the second secondary base station 82 on the secondary base station side at this time, in order for the main base station 83 to know which side of the radio link between the secondary base station and the UE80 is in question, the UE80 needs to explicitly indicate that it is a radio link abnormality or failure with the first secondary base station side.

After the primary base station 83 receives the first secondary base station radio link abnormality information reported by the UE80, the first secondary base station radio link abnormality information includes an identifier of the first secondary base station. From the first secondary base station radio link abnormality information, it is possible to know that the radio link between the UE80 and the first secondary base station 81 has failed. At this time, the main base station 83 needs to transmit the first secondary base station radio link abnormality information to the first secondary base station 81 through the Xn interface, and the first secondary base station 81 stops scheduling to the UE80 after receiving the information. For the downlink data that the first secondary base station 81 needs to send to the UE80, since the scheduling for the UE80 is stopped at this time, data forwarding needs to be performed through the primary base station 83, the data is forwarded to the second secondary base station, and the second secondary base station sends the data to the UE80 in time, so as to reduce the data transmission delay. After the second secondary base station completes transmitting the data forwarded by the first secondary base station to the UE80, the data of the bearer received from the core network may continue to be transmitted to the UE 80.

Specifically, the first auxiliary base station 81 may send PDCP data packets to the second auxiliary base station 82 through the main base station 83, and for each DRB configured with a DAPS, downlink data of the DRB starts from a data packet that the first UE has not confirmed to receive, and the first auxiliary base station 81 sends the PDCP data packets and PDCP sequence numbers (PDCP SNs) corresponding to each PDCP data packet to the second auxiliary base station 82 together. If part of the PDCP packets has been sent by the first secondary base station 81 to the second secondary base station 82 during the previous DAPS configuration procedure, then this part of the PDCP packets does not need to be forwarded.

For the first secondary base station 81, when the radio link between the first secondary base station 81 and the UE80 is abnormal, the first secondary base station 81 may delete the context of the UE80 since the first secondary base station 81 does not need to service the UE80 any more. Through such an operation, not only the storage resource of the first auxiliary base station 81 can be released, but also the main base station 83 can be prevented from notifying the first auxiliary base station 81 to release the context of the UE80 through signaling again after receiving that the UE80 has accessed the second auxiliary base station 82 from the second auxiliary base station 82, and signaling of an air interface can be saved.

For the main base station, after the main base station 83 receives the first secondary base station radio link abnormality information reported by the UE80, the main base station 83 may send the first secondary base station radio link abnormality information to the second secondary base station 82, and after the second secondary base station 82 learns the information, for the bearer configured with the DAPS, the PDCP entity of the bearer needs to be established (the PDCP entity of the bearer is located at the first secondary base station side before), so as to process uplink data reception and process downlink data transmission. Since the second auxiliary base station 82 already knows that the UE detects a radio link failure with the first auxiliary base station side, the second auxiliary base station 82 does not need to send a signaling for releasing the first auxiliary base station to the UE80 through RRC signaling any more, and signaling overhead can be effectively saved.

For the UE80, after transmitting the first secondary base station radio link abnormality information to the main base station 83, the UE80 releases the radio link on the first secondary base station side, i.e., does not need to receive the downlink control signaling and data transmitted by the first secondary base station 81 any more, and does not transmit the uplink signal to the first secondary base station 81 any more. At this point, the UE80 may temporarily save the configuration on the first secondary base station side until the UE80 successfully accesses the second secondary base station 82.

The reason why the configuration on the first secondary base station side is not deleted immediately after the radio link between the UE80 and the first secondary base station side fails is that, at this time, it is not guaranteed that the UE80 can successfully access the second secondary base station 82. If the UE cannot successfully access the second secondary base station 82, the UE80 needs to report the first secondary base station radio link abnormality information to the primary base station again, and through the information, the primary base station 83 may configure other secondary base stations for the UE 80. In configuring the other secondary base stations, the primary base station 83 performs configuration for the UE80 with reference to the configuration information of the first secondary base station 81. Thus, the UE80 may still maintain the configuration of the first secondary base station 81 until the UE80 fails to successfully access the second secondary base station 82, i.e., until the random access of the UE80 at the second secondary base station 82 has not been successful. Once the UE successfully accesses the second secondary base station 82, the UE80 may delete the relevant configuration of the first secondary base station 81.

S516, the UE executes random access and accesses the second auxiliary base station.

S517, the second auxiliary base station sends the random access success information to the main base station and indicates the first auxiliary base station to stop dispatching the UE.

S518, the primary base station sends information to the first secondary base station, instructing the first secondary base station to stop scheduling the UE.

After the UE successfully accesses the second secondary base station, the second secondary base station may instruct the first secondary base station to stop scheduling the UE. For example, the first secondary base station is instructed to stop scheduling for the UE by the master base station transmitting information to the first secondary base station. For example, the second secondary base station may also send indication information to the UE indicating that the UE is disconnected from the first secondary base station.

The transmission method provided by the embodiment of the application is applied to terminal equipment, the terminal equipment is respectively connected with a main base station and a first auxiliary base station, when the auxiliary base station needs to be switched, a main and auxiliary cell updating instruction sent by the main base station is firstly received, the main and auxiliary cell updating instruction comprises an identifier of a second auxiliary base station, and the terminal equipment can know which auxiliary base station needs to be accessed according to the identifier of the second auxiliary base station. For the DRB configured with DAPS handover, before the terminal device completes random access with the second secondary base station, according to the identifier of the second secondary base station, a first protocol entity associated with the second secondary base station under the DRB is established, then, according to the second protocol entity associated with the first secondary base station under the DRB, second downlink data sent by the first secondary base station is received, and the first downlink data and the second downlink data are combined to obtain a corresponding complete and ordered PDCP data packet. The method provided by the embodiment of the application can realize the DAPS handover in a dual-connection scene, so that the terminal equipment can simultaneously receive the downlink scheduling of the first auxiliary base station and the second auxiliary base station in the updating process of the auxiliary base station. Meanwhile, the scheme provided by the embodiment of the application provides an effective processing scheme aiming at the condition that the wireless link at the first auxiliary base station side is abnormal or fails, and realizes effective data transmission through data forwarding, so that the efficiency of data transmission can be improved, and air interface signaling can be saved.

Fig. 9 is a schematic structural diagram of a transmission device according to an embodiment of the present application, and as shown in fig. 9, the transmission device includes a first receiving module 91, a first processing module 92, a second receiving module 93, and a second processing module 94, where:

the first receiving module 91 is configured to receive a primary and secondary cell update instruction sent by a primary base station, where the primary and secondary cell update instruction includes an identifier of a second secondary base station;

the first processing module 92 is configured to establish a first protocol entity associated with the DRB and the second secondary base station according to the identifier of the second secondary base station;

the second receiving module 93 is configured to receive, according to the first protocol entity, first downlink data sent by a second secondary base station, and receive, according to a second protocol entity, second downlink data sent by the first secondary base station, where the second protocol entity is a protocol entity associated with the DRB and the first secondary base station;

the second processing module 94 is configured to combine the first downlink data and the second downlink data to obtain a packet data convergence protocol PDCP data packet corresponding to the DRB.

In a possible implementation manner, the second processing module 94 is specifically configured to:

In one possible implementation, the first processing module 92 is further configured to:

In a possible implementation manner, the second receiving module 93 is specifically configured to:

In a possible implementation manner, the primary and secondary cell update instruction further includes a separate bearer, and the second processing module 94 is further configured to:

In a possible implementation manner, the second receiving module 93 is further configured to, after completing random access with the second secondary base station:

The apparatus provided in the embodiment of the present application may be configured to implement the technical solution of the method embodiment, and the implementation principle and the technical effect are similar, which are not described herein again.

Fig. 10 is a schematic diagram of a hardware structure of a terminal device according to an embodiment of the present application, and as shown in fig. 10, the terminal device includes: at least one processor 101 and a memory 102. The processor 101 and the memory 102 are connected by a bus 103.

Optionally, the model determination further comprises a communication component. For example, the communication component may include a receiver and/or a transmitter.

In particular implementations, execution of computer-executable instructions stored by the memory 102 by the at least one processor 101 causes the at least one processor 101 to perform the transmission methods described above.

For a specific implementation process of the processor 101, reference may be made to the above method embodiments, which implement the principle and the technical effect similarly, and this embodiment is not described herein again.

In the embodiment shown in fig. 10, it should be understood that the Processor may be a Central Processing Unit (CPU), other general-purpose processors, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), etc. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like. The steps of a method disclosed in connection with the present invention may be embodied directly in a hardware processor, or in a combination of the hardware and software modules within the processor.

The memory may comprise high speed RAM memory and may also include non-volatile storage NVM, such as at least one disk memory.

The bus may be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, an Extended ISA (EISA) bus, or the like. The bus may be divided into an address bus, a data bus, a control bus, etc. For ease of illustration, the buses in the figures of the present application are not limited to only one bus or one type of bus.

The present application also provides a computer-readable storage medium, in which computer-executable instructions are stored, and when the computer-executable instructions are executed by a processor, the transmission method as described above is implemented.

The computer-readable storage medium may be implemented by any type of volatile or non-volatile memory device or combination thereof, such as Static Random Access Memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic memory, flash memory, magnetic or optical disk. Readable storage media can be any available media that can be accessed by a general purpose or special purpose computer.

An exemplary readable storage medium is coupled to the processor such the processor can read information from, and write information to, the readable storage medium. Of course, the readable storage medium may also be an integral part of the processor. The processor and the readable storage medium may reside in an Application Specific Integrated Circuits (ASIC). Of course, the processor and the readable storage medium may also reside as discrete components in the apparatus.

The division of the units is only a 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 place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the 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 functions, if implemented in the form of software functional units and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present application or portions thereof that substantially contribute to the prior art may be embodied in the form of a software product stored in a storage medium and including instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present application. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes.

Those of ordinary skill in the art will understand that: all or a portion of the steps of implementing the above-described method embodiments may be performed by hardware associated with program instructions. The program may be stored in a computer-readable storage medium. When executed, the program performs steps comprising the method embodiments described above; and the aforementioned storage medium includes: various media that can store program codes, such as ROM, RAM, magnetic or optical disks.

Finally, it should be noted that: the above embodiments are only used for illustrating the technical solutions of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A transmission method is applied to terminal equipment which is respectively connected with a main base station and a first auxiliary base station, and comprises the following steps:

merging the first downlink data and the second downlink data to obtain a Packet Data Convergence Protocol (PDCP) data packet corresponding to the DRB;

the primary and secondary cell update instruction further includes a separation bearer, and the method further includes:

2. The method of claim 1, wherein the first downlink data comprises first PDCP data packets and a sequence number of each first PDCP data packet; the second downlink data includes second PDCP data packets and a sequence number of each second PDCP data packet.

3. The method of claim 2, wherein merging the first downlink data and the second downlink data to obtain the PDCP data packet corresponding to the DRB comprises:

4. The method according to any one of claims 1-3, further comprising:

5. The method according to claim 4, wherein receiving second downlink data transmitted by the first secondary base station according to the second protocol entity comprises:

6. The method according to claim 4, wherein receiving second downlink data transmitted by the first secondary base station according to the second protocol entity comprises:

7. The method according to any of claims 1-6, wherein after completing random access with the second secondary base station, the method further comprises:

8. A transmission apparatus, comprising:

a second processing module, configured to combine the first downlink data and the second downlink data to obtain a packet data convergence protocol PDCP data packet corresponding to the DRB;

the primary and secondary cell update instruction further includes a separation bearer, and the second processing module is further configured to:

9. The apparatus of claim 8, wherein the first downlink data comprises first PDCP data packets and a sequence number of each first PDCP data packet; the second downlink data includes second PDCP data packets and a sequence number of each second PDCP data packet.

10. The apparatus of claim 9, wherein the second processing module is specifically configured to:

11. The apparatus of any of claims 8-10, wherein the first processing module is further configured to:

12. The apparatus of claim 11, wherein the second receiving module is specifically configured to:

13. The apparatus of claim 11, wherein the second receiving module is specifically configured to:

14. The apparatus of any one of claims 8-13, wherein the second receiving means is further configured to:

15. A terminal device, comprising: at least one processor and memory;

the memory stores computer-executable instructions;

the at least one processor executing computer-executable instructions stored by the memory causes the at least one processor to perform the transmission method of any of claims 1 to 7.

16. A computer-readable storage medium having computer-executable instructions stored thereon which, when executed by a processor, implement the transmission method of any one of claims 1 to 7.