CN112738911B

CN112738911B - Method, device and system for establishing dual-connection transmission data under 5G architecture

Info

Publication number: CN112738911B
Application number: CN202110148525.XA
Authority: CN
Inventors: 王弘; 许丽香; 柯小婉
Original assignee: Samsung Electronics Co Ltd
Current assignee: Samsung Electronics Co Ltd
Priority date: 2016-11-01
Filing date: 2017-04-27
Publication date: 2023-06-23
Anticipated expiration: 2037-04-27
Also published as: CN112738911A

Abstract

The application discloses a method for establishing dual-connection transmission data under a 5G architecture. Comprising the following steps: the method comprises the steps that a mapping function is achieved by a primary cell PCell of UE, a convergence protocol PDCP layer, a radio link control RLC layer, a media access control MAC layer and a physical layer, mapping of quality packet data to a data radio bearer is achieved by a secondary cell SCell of the UE, the convergence protocol PDCP layer, the MAC layer and the physical layer are achieved, wherein the data of the UE are sent to the PCell by a core network, quality packet data Qos Flow is conducted to the data radio bearer by the PCell at the mapping layer, then branching is conducted, then all paths of data are sent to the UE through the PCell and the Scell of the UE, and the data are recombined at the PDCP layer and then sent to an application layer by the UE.

Description

Method, device and system for establishing dual-connection transmission data under 5G architecture

The application is a divisional application of patent application with application date of 2017, 04 month and 27, application number of 201710288179.9 and the name of 'a method, a device and a system for establishing dual-connection transmission data under a 5G architecture'.

Technical Field

The present invention relates to wireless communication technologies, and in particular, to a method, an apparatus, and a system for establishing dual connectivity for a UE under a base station of a 5G system, where data is transmitted to the UE through two or more base stations.

Background

5G refers to fifth generation mobile communication technology. Unlike the first four generations, 5G is not a single wireless technology, but rather a fusion of existing wireless communication technologies. At present, the peak rate of LTE can reach 100Mbps, and the peak rate of 5G can reach 10Gbps, which is improved by 100 times compared with 4G. The existing 4G network has limited spontaneous processing capability, and cannot support the services of partial high-definition video, high-quality voice, augmented reality, virtual reality and the like. The 5G will introduce more advanced technology, and jointly meet the requirement of mobile service traffic growth through higher frequency spectrum efficiency, more frequency spectrum resources, denser cells and the like, solve the problems faced by the 4G network, and construct a network agency with high transmission rate, high capacity, low time delay, high reliability and excellent user experience. As shown in fig. 1, the 5G architecture includes a 5G access network and a 5G core network, and the UE communicates with the data network through the access network and the core network.

In network evolution, the first phase will continue to use LTE base stations while being able to support 5G terminals and use 5G features. Upgrading LTE base stations to support the 5G feature is therefore attractive and desirable to operators. If the LTE base station is upgraded, the LTE base station can be connected to the 5G core network. The present invention refers to an LTE base station capable of connecting to a 5G core network as an LTE eNB.

Fig. 1 is a schematic diagram of the architecture of 5G. The 101 node is a 5G core network comprising a control plane node and a user plane node, which may be different entities. Between the 5G core network and the 5G base station is an NG interface, which comprises a control plane and a user plane. The control plane is the interface between the core network control node and the base station and the user plane interface is the interface between the core network user node and the base station. The base station connected to the 5G core network may be a 5G base station gNB, or a base station of LTE-advanced, referred to as an LTE eNB. The interface between the gnbs is an Xn interface, which includes a user plane interface and a control plane interface. The interface between the gNB and the eLTE base station is also an Xn interface.

The UE may transmit and receive data at two base stations simultaneously, called dual-connectivity. Only one base station is responsible for sending a Radio Resource Control (RRC) message to the UE and interacting with a core network control plane entity, and the base station is called a master base station (MeNB) and the other base station is called an auxiliary base station (SeNB). The UE has a primary cell in the primary base station, which is the primary cell Pcell of the UE, through which an RRC message is sent to the UE, and other cells are secondary cells scells. One cell in the Scell of the secondary base station is the secondary base station primary cell pScell (the function of pScell). There is an uplink physical layer control channel on pScell and no other scells. The cell group of the primary base station is MCG and the cell group of the secondary base station is SCG. The dual connection can also be extended to multiple connections, where there is one primary base station and multiple secondary base stations. These base stations transmit data to the UE, which can increase the throughput of the system and the rate of the UE, and when the quality of the data radio bearer of a certain base station is poor, can transmit the data on the data radio bearer of the other base station with good quality.

The configuration of the UE side auxiliary cell group is configured by an auxiliary base station, and the configuration of the auxiliary base station to the UE is sent to the UE by a main base station through an RRC container. The primary base station does not parse the RRC container. Or parse but do not change the configuration inside the RRC container. There are two types of bearers established in SeNB, one called split bearer (split bearer) and one called SCG bearer. The split-bearer convergence protocol PDCP protocol stack is on the primary base station and the other user plane protocol layers (e.g., radio link control RLC/medium access control MAC/physical layer) are on the secondary base station. The SCG bearer is that all user plane protocol stacks are on an auxiliary base station, including PDCP RLC/MAC/physical layer, the auxiliary base station receives data from a core network, and the data is transmitted to the UE through an air interface after being processed by a user plane.

In the 5G technology, some technologies different from the 4G technology are adopted, for example, on the Qos architecture, the 5G defines a new mode. At the time of data connection (PDU Session) establishment, the core network issues a default Qos policy or/and an authenticated Qos policy to the RAN and the UE. The data connection is the transmission path between the UE to the core network. Including the transmission path between the core network and the base station and the data radio bearer between the base station and the UE. PDU Session is the connection between the UE and the packet data network, which is used to transfer data units, typically one PDU Session is established for one service. The data unit types include IP data, ethernet data and non-IP data. When establishing PDU Session, the core network sends Qos strategy to RAN through NG interface, and sends Qos strategy to UE through NAS interface. The Qos policy includes indication information/description information of the Qos Flow, and further includes specific Qos information, where the specific quality (Qos) information includes at least one of the following: the A data delay target, the B data error rate, the C data priority, the D guaranteed data rate, the E maximum data rate, and other information such as information of an application layer can be contained. The RAN establishes a default DRB according to Qos requirements, and in addition to the default DRB, the RAN may simultaneously establish other DRBs. In the user plane, the core network composes the data packet into Qos Flow, the QoS indication information is added to the data head of Qos Flow, according to the QoS indication information, the RAN can find out the corresponding specific parameters according to the received Qos strategy, and according to the parameters in the Qos strategy, the data of the user plane is used for corresponding processing to meet the quality requirement. The core network sends the data packet with Qos indication information to the RAN, and the RAN maps the Qos Flow to the resources of the access network and the data radio bearer, for example, the RAN decides that the Qos Flow is mapped to a certain data bearer DRB, or establishes a new data bearer DRB for the Qos Flow. When a new DRB is established, the new DRB is determined by the RAN, and can be established after signaling of a core network is received, or after data of a user of the Qos Flow is received, according to Qos indication information contained in a packet header of the Qos Flow, the Qos indication information is combined with a default Qos policy and/or a pre-authentication Qos policy stored by the RAN, the RAN can learn a specific Qos requirement corresponding to the Qos Flow, and according to the Qos requirement, if the current DRB already established is suitable for bearing the data of the Qos requirement, the Qos Flow is transmitted through the DRB. If not, the RAN may decide to set up a new DRB, with which to carry the Qos Flow.

Under the new technology, the previous dual connection establishment procedure is not applicable. For example, in the LTE system, the core network determines a data bearer corresponding to a certain quality requirement, the core network initiates the data bearer, the bearer of the S1 interface (referred to as E-RAB) and the data radio bearer are in a one-to-one correspondence, the bearer of the S1 interface corresponds to a tunnel in the user plane, and the RAN receives data from the tunnel and directly corresponds to the corresponding data radio bearer. In 5G, the NG interface can already have no concept of E-RAB. The RAN decides how to make the data radio bearer and how to establish the dual connection to transfer the data, and none of the previous methods is applicable. The invention researches how to establish dual connection for the UE under a new technology. Including solving the following problems:

1) How to establish split bearer

2) How to set up SCG bearers

3) How to inform the core network of the SCG bearer.

Disclosure of Invention

The invention provides a method for transmitting data by establishing double connections under the new 5G technology. By the method, the connection can be established on two or more base stations for the UE, the throughput of the system is improved, and the reliability and the transmission speed of data reception are improved.

In order to achieve the above purpose, the present application adopts the following technical scheme:

A method of establishing dual connectivity transmission data, comprising:

a base station where a PCell is located sends an auxiliary base station adding request message to the base station where the SCell is located, wherein the message contains configuration information of Qos Flow to be established, and the configuration information contains the identification of the Qos Flow;

the base station where the SCell is located sends an auxiliary base station adding response message to the base station where the PCell is located, wherein the auxiliary base station adding response message comprises configuration information of a user plane configured by the SCell, and the configuration information of the user plane comprises: and the Qos Flow identifier and the user plane tunnel identifier are contained.

The PCell sends a bearer modification message to the core network, wherein the bearer modification message contains configuration information of a user plane on the SCell, and the configuration information of the user plane comprises: the method comprises the steps of Qos Flow identification, user plane IP address and tunnel identification.

Preferably, the base station where the primary cell PCell is located sends an auxiliary base station addition request message carrying to the base station where the auxiliary cell SCell is located: and the tunnel identifier TEID of data forwarding allocated by the base station where the primary cell PCell is located.

Preferably, the base station where the primary cell PCell is located sends an auxiliary base station addition request message to the base station where the auxiliary cell SCell is located, where the auxiliary base station addition request message carries an identifier of a QoS flow for suggesting data forwarding.

Preferably, the base station where the PCell is located receives an auxiliary base station addition response sent by the base station where the SCell is located, where the auxiliary base station addition response carries an identifier of QoS flow required to be forwarded by data and indication information required to be forwarded.

Preferably, the tunnel determined by the auxiliary base station includes a tunnel between the auxiliary base station and the main base station and/or a tunnel between the auxiliary base station and the core network, wherein the tunnel determined by the auxiliary base station is for one PDU Session.

A method of establishing dual connectivity transmission data, comprising,

the base station where the PCell is located sends an auxiliary base station adding request message to the base station where the SCell is located, wherein the auxiliary base station adding message comprises configuration information of a split bearer to be established, and the configuration information comprises an identifier of a DRB or Xn user plane and specific quality information of a data radio bearer;

the base station where the SCell is located sends an auxiliary base station adding response message to the base station where the PCell is located, wherein the auxiliary base station adding response message comprises configuration information of a user plane configured by the SCell, and the configuration information of the user plane comprises: the packet contains an identification of the DRB or Xn user plane, a user plane tunnel identification.

A data transmission system under a 5G network, comprising: at least two base stations, further comprising a user equipment UE, wherein:

The main cell PCell of the UE realizes the mapping function, the convergence protocol PDCP layer, the radio link control RLC layer, the media access control MAC layer and the physical layer, and the auxiliary cell SCell of the UE performs the mapping from the quality packet data to the data radio bearer to realize the convergence protocol PDCP layer, the MAC layer and the physical layer, wherein the method comprises the following steps of

The core network sends the data of the UE to the PCell, the PCell sends the data of the UE to the data radio bearer in the mapping layer by Qos Flow, then the data is split, then the data of each path is sent to the UE through the Pcell and the Scell of the UE, and the UE recombines the data in the PDCP layer and then sends the data to the application layer. Or alternatively

The core network sends the data of the UE to the PCell and Scell, which in the mapping layer send quality packet data Qos Flow to the data radio bearer, and then sends the data to the UE via the PCell and Scell of the UE, which in the layer reassembles the data in the application layer.

A data transmission method under a 5G network, comprising: a base station where an SCell of a secondary cell is located receives a downlink data packet sent by the base station where a primary cell is located, wherein the downlink data packet comprises: information of quality packet data Qos Flow; the base station where the SCell of the secondary cell is located sends an uplink data packet to the base station where the primary cell is located, wherein the uplink data packet carries Qos Flow information and Qos Flow cache information.

Preferably, the information of the Qos Flow in the downlink data packet includes: the identification of the Qos Flow is indirectly indicated by the location of the packet header.

Preferably, the information of Qos Flow in the uplink data packet includes: the identification of the Qos Flow is indirectly indicated by the location of the packet header.

Drawings

FIG. 1 5G is a system architecture diagram;

FIG. 2 is a schematic diagram of the method of the present invention;

FIG. 3 is a schematic diagram of a first embodiment of the invention;

FIG. 4 is a schematic diagram of a second embodiment of the present invention;

FIG. 5 is a schematic diagram of a third embodiment of the invention;

FIG. 6 is a schematic diagram of a fourth embodiment of the invention;

fig. 7 is a schematic diagram of a fifth embodiment of the present invention.

Detailed Description

In order to make the objects, technical means and advantages of the present application more apparent, the present application is further described in detail below with reference to the accompanying drawings.

In 5G, the downlink, core network user plane sends data to the base station, and in NG interface, the core network sends data to the base station in Qos Flow, and the base station maps Qos Flow into Data Radio Bearers (DRBs) and sends the data to the UE. And uplink, the UE transmits data to the base station, the data is born on the DRB, and the base station maps the data on the DRB into Qos Flow and transmits the Qos Flow to the core network. Therefore, a mapping function module is required on the base station to map Qos flows to DRBs (or vice versa, DRBs map to Qos flows). The mapping functions referred to below both include the above two mappings, and for convenience of description, only the mapping of Qos Flow to DRB is described. Fig. 5 is an example illustrating a transmission path of user plane data. Between the core network and the base station, qos Flow1 and Qos Flow 2,Qos Flow 3,Qos Flow4 are data sent to a UE, where Qos Flow1 and Qos Flow 2 belong to the same service data connection (PDU Session). Flow 3 and Qos Flow4 belong to another traffic data connection. The Qos Flow1,Qos Flow 2,Qos Flow 3 is sent through the MeNB, and according to the Qos quality requirement of the Qos Flow, the mapping function on the MeNB maps the Qos flows with the same quality into one DRB, for example, the base station maps the Qos Flow1 and the Qos Flow 2 into DRB1, and the Qos Flow 3 into DRB2. If the MeNB decides to establish a split bearer, for example, DRB2 is established on the SeNB, after PDCP processing of the MeNB, the data is sent to the SeNB through the Xn interface. The SeNB sends the data on DRB2 to the UE through RLC/MAC processing. If the MeNB decides to establish an SCG bearer, e.g. Qos Flow4, to be sent to the UE over the SCG bearer on the SeNB, the MeNB establishes the SCG bearer by the following embodiment, the data is sent by the core network to the SeNB, the mapping function of the SeNB maps the Flow to a DRB, and then sends to the UE through processing of other user planes, e.g. PDCP/RLC/MAC.

Fig. 2 is a method diagram of the present invention, illustrating how split bearers and SCG data bearers are established between a primary base station and a secondary base station. In the following, the base station and the cell are not distinguished, the primary base station refers to the base station where the primary cell is located, and the secondary base station refers to the base station where the secondary cell is located.

Step 201: the primary base station (the base station where the primary cell PCell of the UE is located) transmits a secondary base station addition request to the secondary base station.

And the main base station decides to establish double connection according to the measurement report of the UE and the service quality requirement of Qos Flow or DRB, namely, an auxiliary base station (the base station where the auxiliary cell SCell of the UE is positioned) is established, and data transmission is provided for the UE through the bearing on the main base station and the auxiliary base station. Thus, the data transmission rate can be increased, and the throughput of the system can be improved. When the base station where the PCell is located decides to add a cell as an SCell, the base station where the PCell is located sends an auxiliary base station addition request message to the base station where the SCell is located. The auxiliary base station increasing request message comprises the capability information of the UE, the information of the auxiliary message on the auxiliary base station and the uplink receiving address distributed by the core network, wherein the base station where the PCell is located acquires the uplink receiving address of the data path from the core network, and the base station where the PCell is located sends the uplink receiving address of the data path to the base station where the SCell is located through the auxiliary base station increasing request message.

If the main base station decides to establish split bearing, namely, the main base station performs Qos Flow to DRB mapping in the user plane, the mapped data is processed by PDCP, and then the data is split, and part of the data of the PDCP PDU is sent to the auxiliary base station. The main base station decides to establish split bearing, the main base station sends a message of an auxiliary base station adding request to the auxiliary base station, the message carries information capable of indicating DRB on the MeNB, for example, the information carries a DRB mark, and the corresponding user plane can be uniquely determined through the DRB mark. Or define an identity of a user plane, for example, the MeNB assigns a user plane identity, and uses this identity to indicate splitting of the user plane carried on the Xn interface. The message also carries QoS information corresponding to the DRB. Quality (QoS) information includes at least one of: a data delay target, B data error rate, C data priority, D guaranteed data rate, E maximum data rate. After receiving the message, the auxiliary base station configures a user plane for the split bearer according to the QoS information, configures user plane configuration information of the UE, and allocates transport layer information of the user plane on the Xn interface, for example. For each split bearer, the secondary base station assigns a tunnel identity (Tunnel Endpoint or tunnel ID). Or the main base station sends a message of the auxiliary base station adding request to the auxiliary base station, wherein the message carries the information of PDU Session, such as the identification of PDU Session, and the information of QoS Flow, such as QoS Flow and the corresponding quality requirement information of QoS Flow. After receiving the message, the auxiliary base station configures a user plane for the split bearer according to the QoS information, configures user plane configuration information of the UE, and allocates transport layer information of the user plane on the Xn interface, for example. The secondary base station allocates a tunnel identity (Tunnel Endpoint or tunnel ID) to the bearers belonging to the same PDU Session.

If the primary base station decides to establish the SCG bearer, there are three methods for data processing of the SCG bearer, one is that mapping from Qos Flow to DRB is completed by the primary base station, and other processing of the user plane is performed at the secondary base station, then in the user plane, the SCG bearer is established between the primary base station and the secondary base station, the primary base station maps the Qos Flow to DRB through processing of the mapping function, and then sends the DRB to the secondary base station, and other processing of the user plane is performed at the secondary base station, for example, PDCP/RLC/MAC is performed at the secondary base station. The assisting base station then transmits the data over the air interface to the UE.

The second method is that the MeNB decides the Qos Flow to DRB mapping principle, tells the secondary base station the mapping principle, e.g. which Qos flows are mapped onto the same DRB. And the mapping function of the auxiliary base station maps the Qos Flow to the data radio bearer according to the mapping principle. In the method, the auxiliary base station addition request message carries Qos Flow identifiers, and the Qos Flow identifiers can be a plurality of identifiers of the DRBs corresponding to the Qos Flow identifiers, so that the auxiliary base station can map data indicated by the Qos Flow identifiers to the same DRB. The message also carries specific information of Qos corresponding to the DRB. Or carry Qos policies. The method of policy-carried Qos is described in the following method three.

The third method is that for SCG bearing, the mapping from Qos Flow to DRB is completed by the auxiliary base station, the auxiliary base station obtains Qos Flow strategy, and can decide how to map Qos Flow and DRB according to Qos information of Qos Flow and resource condition of the auxiliary base station, and send configuration information of DRB to UE through the main base station. In this way, the message of step 201 needs to contain an identification of Qos Flow, which indicates which Qos Flow is to be configured as SCG bearer. One or more identifications of Qos flows may be included. The message also contains specific Qos information of the Qos Flow on the SCG bearer. Or the message contains Qos policies of the Qos Flow, which are sent by the core network to the primary base station, which forwards the policies to the secondary base station. The primary base station may transmit the entire Qos policies to the secondary base station, or may transmit only Qos policies corresponding to Qos flows connected to the secondary base station. The message also needs to carry the identity of the PDU Session corresponding to the Qos Flow. Under the second and third methods, since the auxiliary base station needs to allocate tunnels between the auxiliary base station and the core network, for the same PDU Session, only one tunnel is allocated to reduce the number of tunnels, and the data of the entire PDU Session is sent to the base station through the same tunnel, so that the auxiliary base station needs to know which Qos flows belong to the same PDU Session in the Qos flows carried by the auxiliary base station, and can transmit the data through the same tunnel. The identity of the PDU Session is sent by the primary base station to the secondary base station, so the primary base station needs to know the relationship between the PDU Session and the Qos flows, i.e. which Qos flows belong to the same PDU Session. The primary base station may obtain the identifier of the PDU Session and the identifier of its corresponding Qos Flow through a signaling sent by the core network, for example, a PDU Session establishment request message. Or the information of the PDU Session is carried in the mark of the Qos Flow, and whether the PDU Session belongs to the same PDU Session can be known through the mark of the Qos Flow. For example, qos flows belonging to the same PDU Session, their Qos flows identify the same part. Thus, the main base station and the auxiliary base station can know whether they belong to the same PDU Session or not through the identification of the Qos Flow. The adding request message sent by the main base station comprises the identification of the PDU Session and the identification of the Qos Flow, and the auxiliary base station knows which Qos flows belong to the same PDU Session through the identification of the PDU Session and the identification of the Qos Flow, so as to decide whether to allocate a new tunnel or reuse an established tunnel. For example, if the auxiliary base station has not established a tunnel of the user plane for the PDU Session, the auxiliary base station allocates a tunnel identifier of the downlink reception of the new user plane, and sends the tunnel identifier to the core network through the main base station. If a tunnel of the user plane has been established for the PDU Session between the secondary base station and the core network, the secondary base station transmits the tunnel identification to the core network via the primary base station. If a tunnel of a user plane can be established for each Qos Flow between the auxiliary base station and the core network, the auxiliary base station only needs to know the Qos Flow information, and the main base station does not need to send the PDU Session identifier to the auxiliary base station.

In summary, the secondary base station addition request message may contain one or more of the following information:

v DRB identity (or/and identity of Split bearer Xn user plane)

Identification of Qos Flow

The Qos Flow strategy (or the specific requirements of Qos)

Identification of a PDU Session

The DRB in the present invention may be replaced by other names, such as Xn bearer or data bearer, as long as the bearer and the DRB have a corresponding relationship. If other names are substituted, the identification of the DRB is replaced accordingly, for example by the identification of an Xn bearer or a data bearer. In the information sent to the UE by the base station, the radio bearer is identified by the DRB, and the bearers on the Xn interface can be identified by other names, but there is a correspondence with the DRB, from which the base station can learn that the data of these bearers are in one-to-one correspondence. The correspondence may be assumed to use the same value.

Step 202: the secondary base station transmits a secondary base station addition response message to the primary base station.

The message carries bearer configuration information for the UE. And the configuration information of the UE configured by the auxiliary base station is carried in an RRC container and sent to the main base station. The primary base station does not parse the RRC container and forwards the RRC container to the UE. The message carries transport layer information of the user plane allocated to the bearer, for example, for each split bearer, the auxiliary base station allocates a tunnel identifier. For SCG bearers, the secondary base station allocates one tunnel identifier for each PDU Session or one tunnel identifier for each Qos Flow or one tunnel identifier for one DRB.

In summary, the secondary base station addition response message may contain one or more of the following information:

v DRB identity (or identity of Split bearer Xn user plane)

Identification of Qos Flow

Identification of a PDU Session

Layer information, e.g. tunnel identity

V RRC container

Step 203: the master base station sends a bearer modification message to the core network.

The message contains the identifier of the Qos Flow and the corresponding downlink received transport layer information, such as an IP address and a tunnel identifier, or contains the PDU Session, the identifier of the Qos Flow, and the downlink received IP address and the tunnel identifier allocated for the PDU Session.

In summary, the bearer modification message may contain one or more of the following information:

identification of Qos Flow

Identification of a PDU Session

Layer information, such as IP address and tunnel identification

Fig. 3 is a schematic flow chart of establishing split bearer for service in the present invention. The method comprises the following steps:

step 301, a control plane node of the core network receives a PDU session establishment request message. The message may be sent to the control plane by a user plane node of the core network or by other nodes of the core network.

The PDU session establishment request establishes a data connection from the core network to the UE for a certain service given to the UE. The message contains configuration information of the PDU data. One pdu use may consist of multiple Qos flows. The Qos requirements are different for each Qos Flow, and the message may contain an identification of the Qos Flow and the corresponding specific Qos requirements. The message may also contain a default Qos policy, a pre-configured Qos policy. The Qos policy includes indication information/description information of the Qos Flow, and further includes specific Qos information, where the specific quality (Qos) information includes at least one of the following: the A data delay target, the B data error rate, the C data priority, the D guaranteed data rate, the E maximum data rate, and other information such as information of an application layer can be contained.

Step 302, the core network sends a message to a base station of the access network.

The control node of the core network sends a PDU Session establishment request message to the base station, the message carries an identifier of the PDU Session, and the identifier uniquely identifies the service of a certain UE. The message also carries transport layer information of the user plane of the core network, such as an IP address and a tunnel identification, which identifies the upstream receiving address of the data path. The message also carries a default Qos policy, and/or a pre-configured Qos policy. The Qos policy includes indication information/description information (ID or descriptor) of the Qos Flow, and further includes specific Qos information, where the specific quality (Qos) information includes at least one of the following: the A data delay target, the B data error rate, the C data priority, the D guaranteed data rate, the E maximum data rate, and other information such as information of an application layer can be contained. The data of one PDU Session may have a plurality of different Qos flows, each Qos Flow may have a corresponding processing policy, and one PDU Session establishment request message may include a plurality of Qos policies. The message may also carry information to be sent by the core network to the UE, which may be carried by a container (NAS container) of the non-access stratum.

The base station receives the following actions: the base station stores the received Qos strategy and processes the following user plane data according to the Qos strategy. And the base station receives the PDUSion establishment request message, and at least one default data radio bearer DRB is required to be established according to the Qos strategy. The base station may also establish other data bearers at the same time.

In step 303, the base station sends a message to the UE.

The base station sends RRC configuration request information to the UE, the information carries Qos strategy sent to the UE by the core network, the strategy can be transmitted to the UE through a container (NAS container) of a non-access layer, and the configuration information of DRB configured by the base station to the UE is also included.

In step 304, the ue sends a message to the base station.

The UE sends an RRC configuration complete message to the base station. The message carries acknowledgement information that the UE successfully configured the DRB.

In step 305, the base station sends a PDU Session establishment success message to the core network.

And after the configuration of the base station is completed, the base station sends a successful confirmation message to a control node in the core network. The message carries transport layer information allocated by the base station for the user plane, such as an IP address and a tunnel identifier for downlink data reception.

Step 306, the core network control node sends a message to the user plane node.

If the control node and the user node of the core network are not together, the control node sends a message to the user plane node, wherein the message carries information of Qos Flow, such as identification of PDU Session, identification/description information of Qos Flow, and transport layer information distributed by the base station for the user plane of PDU Session, such as IP address and tunnel identification of downlink data reception.

A pduse may establish only one tunnel between the core network user plane and the base station.

In step 307, the data of the user plane may start to be transmitted. For example, in downlink, the core network composes the data packet into Qos Flow, adds Qos indication information to the data header of Qos Flow, and sends the data packet with Qos indication information to the RAN. If the data is the data (non-GBR) which does not ensure reliable transmission, the core network does not need to initiate the signaling of the control plane, and the data processed by the method is directly sent to the RAN node, namely the base station.

In step 308, the base station receives the data of the user plane, and obtains Qos information of the data packet according to the packet header information, and the base station needs to have a Qos Flow to DRB mapping function. The mapping function module maps one or more Qos flows onto one DRB, and the mapping principle mainly refers to Qos of the Qos flows. For example, the packet header indicates Qos Flow-1, according to the stored Qos policy, it can be known that the specific Qos requirement corresponding to Qos Flow-1 can be met by the default DRB or by a certain DRB already established, and the base station can decide to send the data packet to the UE through a suitable DRB. If there are multiple Qos flows, such as Qos Flow-1, qos Flow-2, and Qos Flow-3, where Qos Flow-1 and Qos Flow-3 have the same or close Qos requirements, the base station may map the data of Qos Flow-1 and Qos Flow-3 to the same DRB for transmission. The data is transmitted to the UE via the air interface through the processing of the mapping function, through the processing of layer 2, for example, through the processing of PDCP/RLC/MAC layers.

In step 309, the primary base station sends an auxiliary base station addition request to the destination auxiliary base station.

The main cell of the UE on the base station receives the measurement report of the user, the signal quality of a certain cell on the adjacent base station meets the requirement, the main cell on the main base station decides to establish an auxiliary cell on the auxiliary base station, and the data transmission is shared by double connection. The base station decides to send data also via the secondary base station, i.e. establish Split bearers, to one or several DRBs originally on the MeNB. When the base station where the PCell is located decides to add a cell as an SCell, the base station where the PCell is located sends an auxiliary base station addition request message to the base station where the SCell is located. The auxiliary base station increasing request message comprises the capability information of the UE, the information of the auxiliary message on the auxiliary base station and the uplink receiving address distributed by the core network, wherein the base station where the PCell is located acquires the uplink receiving address of the data path from the core network, and the base station where the PCell is located sends the uplink receiving address of the data path to the base station where the SCell is located through the auxiliary base station increasing request message.

The primary base station sends a message of the auxiliary base station adding request to the auxiliary base station, wherein the message carries information capable of indicating the DRB on the MeNB, for example, the message carries an identifier of the DRB, and the corresponding user plane can be uniquely determined through the DRB identifier. Or define an identity of a user plane, e.g. the MeNB assigns a user plane identity, which is used to identify its corresponding user plane. The message also carries Qos requirements corresponding to the DRB. After receiving the message, the auxiliary base station configures a user plane for the split bearer according to the Qos requirement, configures user plane configuration information of the UE, and allocates transport layer information of the user plane on the Xn interface, for example. And distributing a tunnel identifier to each split bearer by the auxiliary base station.

In another implementation method, the primary base station sends a message of the auxiliary base station adding request to the auxiliary base station, where the message carries information of the PDU Session, for example, an identifier of the PDU Session, and information of the QoS Flow, for example, a QoS Flow identifier list, and quality requirement information corresponding to the QoS Flow. After receiving the message, the auxiliary base station configures a user plane for the split bearer according to the quality requirement of QoS, configures user plane configuration information of the UE end, and allocates transport layer information of the user plane on the Xn interface, for example. And allocating a tunnel identification TEID to the bearer belonging to the same PDU Session by the auxiliary base station.

In step 310, the secondary base station sends a secondary base station addition response message to the primary base station.

The auxiliary base station decides the configuration information of the load on the UE according to the Qos of the DRB and the UE capability, and the target base station includes the configuration information of the auxiliary load or the auxiliary cell on the UE in an RRC container and forwards the container to the UE through the main base station. The UE sets the protocols of the UE-side layers, such as RLC, MAC layer, according to the configuration. The message also carries the DRB identity or the identity of the Xn user plane, which corresponds to the transport layer information, e.g. tunnel identity. If the bearer belonging to the same PDU Session is allocated with a tunnel identification TEID, the message of the auxiliary base station sending the auxiliary base station increasing response message contains the identification of the PDU Session and the tunnel identification TEID allocated for the PDU. In this case, the flow control of the user plane also needs to be modified. A specific flow control process is described in the corresponding embodiment of fig. 7.

In step 311, the primary base station sends an RRC reconfiguration request to the UE.

The primary base station does not parse the RRC container and forwards the RRC container to the UE. The primary base station may add its own configuration information for the UE and send it to the UE together with the information of the secondary base station configuration.

Step 312: the UE transmits an RRC reconfiguration complete message to the primary base station.

And after the UE is configured successfully, sending a response message to the main base station. The response message includes the response to the configuration information sent in step 311, that is, includes a response to the configuration information of the primary base station, and also includes a response to the secondary base station location information. The UE also needs to perform a random access procedure with the new assisting base station and synchronize with the new assisting base station, if necessary. After synchronization, the assisting base station may begin transmitting data to the UE.

Step 313: the primary base station transmits an RRC reconfiguration complete message to the secondary base station.

The main base station informs the auxiliary base station that the configuration of the UE end has been successful. Because the UE sent the acknowledgement message to the primary base station, the primary base station needs to forward the acknowledgement message to the secondary base station. If the primary base station cannot resolve the response of the UE to the configuration information of the secondary base station, the primary base station may also forward the response of the UE to the configuration information of the secondary base station to the secondary base station in the form of an RRC container. For example, the primary base station is an eLTE base station, the secondary base station is a 5G base station gNB, or the primary base station is a 5G base station, and the secondary base station is an eLTE base station.

Thereafter, the data is transmitted from the primary base station to the secondary base station. The secondary base station also sends traffic control information to the primary base station.

So far, the Split bearer establishment process is completed.

Fig. 4 is a schematic flow chart of setting up an SCG bearer for a service in the present invention. The method comprises the following steps:

in step 401, the control plane node of the core network receives the PDU session establishment request message. The message may be sent to the control plane by a user plane node of the core network or by other nodes of the core network.

Step 402, the core network sends a message to a base station of the access network.

In step 403, the base station sends a message to the UE.

In step 404, the ue sends a message to the base station.

In step 405, the base station sends a PDU Session establishment success message to the core network.

In step 406, the core network control node sends a message to the user plane node.

In step 407, the data of the user plane may start to be transmitted. For example, in downlink, the core network composes the data packet into Qos Flow, adds Qos indication information to the data header of Qos Flow, and sends the data packet with Qos indication information to the RAN. If the data is the data (non-GBR) which does not ensure reliable transmission, the core network does not need to initiate the signaling of the control plane, and the data processed by the method is directly sent to the RAN node, namely the base station.

In step 408, the base station receives the data of the user plane, obtains Qos information of the data packet according to the data packet header information, and needs a Qos Flow to DRB mapping function. The mapping function module maps one or more Qos flows onto one DRB, and the mapping principle mainly refers to Qos of the Qos flows. For example, the packet header indicates Qos Flow-1, according to the stored Qos policy, it can be known that the specific Qos requirement corresponding to Qos Flow-1 can be met by the default DRB or by a certain DRB already established, and the base station can decide to send the data packet to the UE through a suitable DRB. If there are multiple Qos flows, such as Qos Flow-1, qos Flow-2, and Qos Flow-3, where Qos Flow-1 and Qos Flow-3 have the same or close Qos requirements, the base station may map the data of Qos Flow-1 and Qos Flow-3 to the same DRB for transmission. The data is transmitted to the UE via the air interface through the processing of the mapping function, through the processing of layer 2, for example, through the processing of PDCP/RLC/MAC layers.

Step 409, the primary base station sends an auxiliary base station addition request to the auxiliary base station.

The main cell of the UE on the base station receives the measurement report of the user, the signal quality of a certain cell on the adjacent base station meets the requirement, the main cell on the main base station decides to establish an auxiliary cell on the auxiliary base station, and the data transmission is shared by double connection. The base station decides to send data through the secondary base station, i.e. establish SCG bearers, with one or several Qos flows originally on the MeNB. The method comprises the steps that a main base station sends an auxiliary base station adding request to an auxiliary base station, the auxiliary base station adding request message comprises capability information of UE, information of auxiliary information on the auxiliary base station and uplink receiving addresses distributed by a core network, a base station where a PCell is located obtains the uplink receiving addresses of a data path from the core network, and the base station where the PCell is located sends the uplink receiving addresses of the data path to the base station where the SCell is located through the auxiliary base station adding request message.

If the primary base station decides to establish the SCG bearer, there are two methods for data processing of the SCG bearer, one is that the mapping from Qos Flow to DRB is completed by the primary base station, the other user plane processes are in the auxiliary base station, the primary base station maps Qos Flow to DRB through the mapping function process, and then sends the DRB to the auxiliary base station, and the other user plane processes are all carried out on the auxiliary base station. The primary base station sends a message of the auxiliary base station adding request to the auxiliary base station, wherein the message carries information capable of indicating the DRB on the MeNB, for example, the message carries an identifier of the DRB, and the corresponding user plane can be uniquely determined through the DRB identifier. Or define an identity of a user plane, e.g. the MeNB assigns a user plane identity, which is used to identify its corresponding user plane. The message also carries Qos requirements corresponding to the DRB. After receiving the message, the auxiliary base station configures a user plane for the SCG bearer according to the Qos requirement, configures user plane configuration information of the UE, and allocates transport layer information of the user plane on the Xn interface, for example. And allocating a tunnel identifier to each SCG bearer by the auxiliary base station.

The second method is that the MeNB decides the mapping of Qos flows to DRBs, tells the decision to the secondary base station, and the secondary base station maps Qos flows to DRBs according to the configuration of the MeNB. In the method, the auxiliary base station increases the request to carry Qos Flow identifiers, and the Qos Flow identifiers can be a plurality of identifiers of the DRBs corresponding to the Qos Flow identifiers, so that the auxiliary base station can map the data indicated by the Qos Flow identifiers to the same DRB. The message also carries Qos information corresponding to the DRB. Or a Qos policy that carries Qos Flow. The carrying method is described in detail in method three below.

The third method is that for SCG bearing, the mapping from Qos Flow to DRB is completed by the auxiliary base station, the auxiliary base station obtains Qos Flow strategy, and can decide how to map Qos Flow and DRB according to Qos requirement of Qos Flow and resource condition of the auxiliary base station, and send configuration information of DRB to UE through the main base station. In this method, the secondary base station added message of this step contains an identification of Qos Flow, which indicates which Qos Flow is to be configured as an SCG bearer. One or more identifications of Qos flows may be included. The message also contains specific Qos requirements of the Qos Flow on the SCG bearer. Or the message contains Qos policies of the Qos Flow, which are sent by the core network to the primary base station, which forwards the policies to the secondary base station. The primary base station may transmit the entire Qos policies to the secondary base station, or may transmit only Qos policies corresponding to Qos flows connected to the secondary base station. The message also needs to carry the identity of the PDU Session corresponding to the Qos Flow. Under the second and third methods, since the auxiliary base station needs to allocate tunnels between the auxiliary base station and the core network, for the same PDU Session, only one tunnel is allocated to reduce the number of tunnels, and the data of the entire PDU Session is sent to the base station through the same tunnel, so that the auxiliary base station needs to know which Qos flows belong to the same PDU Session in the Qos flows carried by the auxiliary base station, and can transmit the data through the same tunnel. The PDU Session is sent by the primary base station to the secondary base station, so the primary base station needs to know the relation between the PDU Session and the Qos flows, i.e. which Qos flows belong to the same PDU Session. The primary base station may obtain the identifier of the PDU Session and the identifier of its corresponding Qos Flow through a signaling sent by the core network, for example, a PDU Session establishment request message. Or the information of the PDU Session is carried in the mark of the Qos Flow, and whether the PDU Session belongs to the same PDU Session can be known through the mark of the Qos Flow. For example, qos flows belonging to the same PDU Session, their Qos flows identify the same part. Thus, the main base station and the auxiliary base station can know whether they belong to the same PDU Session or not through the identification of the Qos Flow. If a tunnel can be established for each Qos Flow between the secondary base station and the core network, the primary base station does not need to send the identity of the PDU Session to the secondary base station.

For SCG bearers, if a handover from the primary base station to the secondary base station occurs, the primary base station needs to forward the buffered data to the secondary base station. If there are multiple QoS flows on the SCG bearer, then the primary base station may decide to switch a certain QoS flow on the secondary base station to the primary base station while the SCG bearer remains on the secondary base station. In the process that the main base station sends the auxiliary base station adding request message, the main base station distributes the uplink address TEID for data forwarding. When a certain QoS flow is switched to the primary base station, the secondary base station sends the buffered data to the uplink address. According to the quality requirement of the QoS flows, the primary base station can suggest that some QoS flows need data forwarding according to the buffering condition, so that the auxiliary base station adds the identifiers of the QoS flows which suggest data forwarding in the request message. Under the second approach above, the suggested identification of data forwarding may be for DRBs.

In step 410, the secondary base station sends a secondary base station addition response message to the primary base station.

The auxiliary base station decides the configuration information of the load on the UE according to the Qos of the DRB and the UE capability, and the target base station includes the configuration information of the auxiliary load or the auxiliary cell on the UE in an RRC container and forwards the container to the UE through the main base station. The UE sets the protocols of each layer of the UE end, such as PDCP, RLC and MAC layers according to the configuration. The message also carries an identification of the DRB or an identification of the Xn user plane, which corresponds to the transport layer information, e.g. the tunnel identification. Or the message contains PDU Session identifications and/or Qos Flow identifications, and the auxiliary base station allocates a tunnel identification for each PDU Session or allocates a tunnel identification for each Qos Flow. If a tunnel identification is assigned to each PDU Session, the message contains the identification of the PDU Session. The auxiliary base station refers to the proposal information of the main base station and the configuration information of the radio bearer of the auxiliary base station in the target cell to determine which Qos flows need to forward data, and the auxiliary base station sends an auxiliary base station adding response message which also carries the mark of the QoS flows needing to forward data and the indication information needing to forward. The indication information to be forwarded may contain transport layer information, such as an IP address and a tunnel identification, that assist the base station in forwarding the data. In addition to data forwarding for one QoS flow, data forwarding for DRBs may be performed, where the message includes an identifier of the DRB and transport layer information for assisting the base station in forwarding data, such as an IP address and a tunnel identifier. In particular, the mechanism of data forwarding may be one of the following ways:

a: a data forwarding tunnel for the PDU Session is established between the primary base station and the secondary base station. The auxiliary base station establishes a tunnel identification for data forwarding for the PDU Session and sends the tunnel identification to the main base station. Data belonging to the same PDU Session is forwarded through the same tunnel. When forwarding data, the data packet header contains the identifier of the QoS Flow, and the auxiliary base station maps the QoS Flow to the DRB according to the identifier of the QoS Flow. The data stored by the main base station may be data packets which are not mapped to the DRB, and when the data packets are sent from the core network to the main base station, the main base station may directly send the data packets to the auxiliary base station when the packet header already carries the QoS Flow identifier. The main base station also stores the data packet mapped to the DRB, the data packet mapped to the DRB is sent to the PDCP protocol layer, and the PDCP protocol layer needs to know the identification of the QoS Flow corresponding to the PDCP data packet and can be obtained through interaction information among the internal protocol layers. When forwarding the PDCP data packet, the main base station sends the PDCP data packet through a tunnel corresponding to the PDU Session, wherein the tunnel protocol is GTP-U protocol, and the packet header of the GUP-U contains the QoS Flow mark and indicates the QoS Flow corresponding to the forwarded PDCP data packet.

b: a data forwarding tunnel for the DRB is established between the primary base station and the secondary base station. The auxiliary base station allocates a tunnel identifier for data forwarding to each DRB. Under the second method above, i.e. the MeNB decides the mapping of Qos flows to DRBs, tells the secondary base station the decision, which maps Qos flows to DRBs according to the configuration of the MeNB. The auxiliary base station establishes a tunnel identifier for data forwarding for the DRB and sends the tunnel identifier to the main base station. Data belonging to the same DRB is forwarded through the same tunnel. The forwarding method is similar to the current double-link data forwarding method. The data stored by the main base station may be a data packet which is not mapped to the DRB yet, and when the data packet is sent from the core network to the main base station, the main base station needs to map the data to the DRB for data forwarding when the packet header already carries the QoS Flow identifier, and then forwards the data to the auxiliary base station through the tunnel corresponding to the DRB. And the auxiliary base station receives the forwarded data and sends a data packet to the UE on the corresponding DRB.

a: the method a and the method b are combined, two data forwarding tunnels are established between the main base station and the auxiliary base station, one tunnel is aimed at PDU Session, and the other tunnel is aimed at DRB. The auxiliary base station addition response message sent by the auxiliary base station may include the PDU Session identifier and its corresponding tunnel information, such as an IP address and a tunnel identifier, or include the DRB identifier and its corresponding tunnel information, such as an IP address and a tunnel identifier. The data stored by the main base station may be a data packet which is not mapped to the DRB yet, and when the data packet is sent from the core network to the main base station, the main base station sends the data packet through a tunnel for PDU Session when the packet header already carries the QoS Flow identifier. The auxiliary base station receives the forwarded data, maps the data packet to the DRB, and sends the data packet to the UE on the DRB. The primary base station also stores the data packets that have been mapped to the DRBs, and the data packets mapped to the DRBs are transmitted to the PDCP protocol layer, and the data packets stored in the PDCP protocol layer are transmitted through a tunnel for the DRBs. And the auxiliary base station receives the forwarded data and sends a data packet to the UE on the corresponding DRB.

It should be noted that, although the described data forwarding method is in the embodiment of SCG bearer establishment, the method of the present invention is also applicable to other bearer manners. Only the bearer type is changed into the corresponding bearer type.

In step 411, the primary base station sends an RRC reconfiguration request to the UE.

Step 412: the UE transmits an RRC reconfiguration complete message to the primary base station.

And after the UE is configured successfully, sending a response message to the main base station. The response message contains the response to the configuration information sent in step 411, i.e. the response to the configuration information of the primary base station, and also the response to the secondary base station. The UE also needs to perform a random access procedure with the new assisting base station and synchronize with the new assisting base station, if necessary. After synchronization, the assisting base station may begin transmitting data to the UE.

Step 413: the primary base station transmits an RRC reconfiguration complete message to the secondary base station.

Step 414: the main base station sends a bearer modification request message to the core network control node.

Step 415: the core network control node sends a load modification request message to the core network user node to inform the new downlink received transport layer information.

Step 416: the core network user node sends a bearer modification response message to the core network control node acknowledging receipt 415 of the message of step.

Step 417: the core network control node sends a bearer modification response message to the base station acknowledging receipt of the message of step 415.

Step 418: if the data forwarding exists, the main base station initiates the data forwarding step and sends sequence number state information to the auxiliary base station. The assisting base station sets the sequence number of the user data with reference to the information.

So far, the SCG bearer establishment procedure is completed.

Fig. 6 is a schematic diagram of a base station apparatus. In the base station, a mapping function module is added, and the mapping function module maps the Qos Flow into DRB or maps the DRB into Qos Flow.

Fig. 7 is a data format of transmission between a primary base station and a secondary base station, where for split bearers, the primary base station splits data and sends the split data to a UE through the primary base station and the secondary base station, respectively. In order for the primary base station to perform reasonable data segmentation, the secondary base station needs to transmit a piece of rate control information, which is referenced by the primary base station to determine how to segment the data. The first table is the data format sent by the primary base station to the secondary base station. The method comprises format type indication, qoS Flow identification and serial number of Xn interface. The format type indicates the type of user data format, e.g. "0" represents the data format transmitted by the primary base station to the secondary base station. The sequence number of the Xn interface is a sequence number allocated to a data packet of a certain QoS flow on the Xn interface by the main base station, and the sequence number is increased by 1 when one data packet is sent.

The first table is the data format sent by the primary base station to the secondary base station. The format type indication is included, the data buffering information of the first QoS Flow is next to the data buffering information of the second QoS Flow, and the data buffering information of the nth QoS Flow is up to the data buffering information of the nth QoS Flow. When the split bearer is established, the primary base station tells the secondary base station which QoS flows are established to the secondary base station through the QoS Flow identification list contained in the secondary base station establishment request message. The second format contains the buffer information corresponding to these QoS flows. The order is consistent with the order of the QoS Flow identification list. If the primary base station establishes or deletes some QoS flows established on the secondary base station, the corresponding QoS Flow positions in the table are adjusted accordingly. For example, when the QoS Flow of the first location is deleted from the secondary base station, the second QoS Flow in the original table moves upward to become the QoS Flow of the first location.

The third table is the data format sent by the secondary base station to the primary base station, and includes a format type indication, a QoS Flow identifier, data buffer information, and Xn data loss information. The data buffer information is the expected buffer size information of the auxiliary base station for the QoS flow, and the main base station can adjust the proportion of data segmentation according to the information. The Xn data loss information indicates which data is lost when Xn is transmitted, and the auxiliary base station can learn which data is lost when Xn is transmitted according to the serial number of the Xn interface in the first table.

The fourth table is the data format sent by the secondary base station to the primary base station, and includes format type indication, data buffer information of the first QoS Flow, and the next data buffer information of the second QoS Flow, until the data buffer information of the nth QoS Flow. When the split bearer is established, the primary base station tells the secondary base station which QoS flows are established to the secondary base station through the QoS Flow identification list contained in the secondary base station establishment request message. The fourth format includes buffer information corresponding to the QoS flows. The order is consistent with the order of the QoS Flow identification list. The data buffer information is the expected buffer size information of the auxiliary base station for the QoS flow, and the main base station can adjust the proportion of data segmentation according to the information. The Xn data loss information indicates which data is lost when Xn is transmitted, and the auxiliary base station can learn which data is lost when Xn is transmitted according to the serial number of the Xn interface in the first table. If the primary base station establishes or deletes some QoS flows established on the secondary base station, the corresponding QoS Flow positions in the table are adjusted accordingly. For example, when the QoS Flow of the first location is deleted from the secondary base station, the second QoS Flow in the original table moves upward to become the QoS Flow of the first location.

The foregoing description of the preferred embodiments of the invention is not intended to be limiting, but rather to enable any modification, equivalent replacement, improvement or the like to be made within the spirit and principles of the invention.

Claims

1. A method performed by a primary base station in a wireless communication system, the method comprising:

transmitting an auxiliary base station addition request message to an auxiliary base station, wherein the auxiliary base station addition request message comprises an identification of a protocol data unit PDU session, information of a service quality QoS flow associated with the PDU session and quality requirement information associated with the QoS flow;

receiving an auxiliary base station addition response message from an auxiliary base station, the auxiliary base station addition response message comprising an identification of a data radio bearer, DRB, an identification of the PDU session, transport layer information of a user plane, and a radio resource control, RRC, container comprising configuration information of an auxiliary cell associated with the auxiliary base station; and

and sending the RRC reconfiguration message comprising the RRC container to the User Equipment (UE).

2. The method according to claim 1,

the transport layer information of the user plane comprises a tunnel identifier (TEID) of the user plane on the Xn interface.

3. The method of claim 1, further comprising:

receiving an RRC reconfiguration complete message from the UE as a response to the RRC reconfiguration message, an

And sending the RRC reconfiguration complete message to the auxiliary base station.

4. The method according to claim 1,

wherein the quality requirement information associated with the QoS flow includes at least one of QoS flow description information, data delay information, data error rate, priority, guaranteed data rate, or maximum data rate.

5. A method performed by an assisting base station in a wireless communication system, the method comprising:

receiving a secondary base station addition request message from a primary base station, the secondary base station addition request message comprising an identification of a protocol data unit, PDU, information of a quality of service, qoS, flow associated with the PDU session, and quality requirement information associated with the QoS flow;

and transmitting an auxiliary base station addition response message to the main base station, wherein the auxiliary base station addition response message comprises the identification of the data radio bearer DRB, the identification of the PDU session, the transmission layer information of the user plane and a radio resource control RRC container, and the RRC container comprises the configuration information of a secondary cell associated with the auxiliary base station.

6. The method according to claim 5,

7. The method of claim 5, further comprising:

in case that the RRC reconfiguration complete message is received by the master base station from the user equipment UE as a response to the RRC reconfiguration message including the RRC container, the RRC reconfiguration complete message is received from the master base station.

8. The method according to claim 5,

9. A primary base station in a wireless communication system, the primary base station comprising:

a transmitting module and a receiving module,

the transmission module is configured to transmit a secondary base station addition request message to a secondary base station, the secondary base station addition request message comprising an identification of a protocol data unit, PDU, information of a quality of service, qoS, flow associated with the PDU session, and quality requirement information associated with the QoS flow,

the receiving module is configured to receive an auxiliary base station addition response message from an auxiliary base station, the auxiliary base station addition response message comprising an identification of a data radio bearer, a PDU session, transport layer information of a user plane, and a radio resource control, RRC, container comprising configuration information of a secondary cell associated with the auxiliary base station, and

The sending module is further configured to send an RRC reconfiguration message including the RRC container to the user equipment UE.

10. The main base station according to claim 9,

11. The main base station according to claim 9,

wherein the receiving module is further configured to receive an RRC reconfiguration complete message from the UE as a response to the RRC reconfiguration message, and

wherein the sending module is further configured to send the RRC reconfiguration complete message to the secondary base station.

12. The main base station according to claim 9,

13. An assisting base station in a wireless communication system, the assisting base station comprising:

a receiving module configured to receive a secondary base station addition request message from a primary base station, the secondary base station addition request message comprising an identification of a protocol data unit, PDU, information of a quality of service, qoS, flow associated with the PDU session, and quality requirement information associated with the QoS flow; and

A transmitting module configured to transmit a secondary base station addition response message to the primary base station, the secondary base station addition response message comprising an identification of a data radio bearer, DRB, an identification of the PDU session, transport layer information of a user plane, and a radio resource control, RRC, container comprising configuration information of a secondary cell associated with the secondary base station.

14. The auxiliary base station according to claim 13,

15. The auxiliary base station according to claim 13,

wherein the receiving module is further configured to receive an RRC reconfiguration complete message from the primary base station in case the RRC reconfiguration complete message is received by the primary base station from the user equipment UE as a response to the RRC reconfiguration message comprising the RRC container.

16. The auxiliary base station according to claim 13,