CN109548095B

CN109548095B - Method and device for switching serving cells

Info

Publication number: CN109548095B
Application number: CN201710681888.3A
Authority: CN
Inventors: 汪巍崴; 柯小婉; 王弘; 许丽香
Original assignee: Samsung Electronics Co Ltd
Current assignee: Samsung Electronics Co Ltd
Priority date: 2017-08-10
Filing date: 2017-08-10
Publication date: 2022-12-30
Anticipated expiration: 2037-08-10
Also published as: CN116367249A; CN109548095A; CN116112995A

Abstract

The embodiment of the invention provides a method and a device for switching a service cell, wherein the method for switching the service cell comprises the following steps: the auxiliary node sends an auxiliary node modification demand message to the main node, so that the main node switches the service cell according to the auxiliary node modification demand message and releases the bearer to be released; and the auxiliary node receives an auxiliary node modification confirmation message returned by the main node aiming at the auxiliary node modification requirement message. The method provided by the embodiment of the invention realizes that when the bearer to be released exists in the service cell switching process, the service cell is switched according to the auxiliary node modification demand message and the bearer to be released on the auxiliary node is released, thereby greatly improving the signaling transmission efficiency and saving the signaling resources.

Description

Method and device for switching serving cells

Technical Field

The present invention relates to the field of wireless communication technologies, and in particular, to a method and an apparatus for switching serving cells.

Background

In order to improve the throughput of users, the LTE system introduces the concept of dual connectivity (dual connectivity), i.e., one user can be connected to two different base stations at the same time. In an NR (New Radio access) network or a fifth generation 5G network, the concept of Dual Connectivity is further extended, and multiple Connectivity (MR-DC) of multiple different access technologies is introduced, that is, a user may simultaneously access base stations supporting different access technologies, for example, two base stations accessed by the user support LTE and NR respectively. In the following discussion, we use MN (Master Node) and SN (Secondary Node) to represent two base stations accessed by a user, as shown in fig. 1. The possible air interface access technologies of each node are LTE, NR, and the like, and each node may access a core network of a 5G system or a core network of a 4G/LTE system. In the above scenario, the following concepts are introduced:

■ MCG (Master Cell Group ): cell group for user access on MN. Among the MCG cells, one is a special Cell (PCell: primary Cell) and the others are Secondary cells (SCell: secondary Cell). The change of the PCell can trigger the process of random access of the user, meanwhile, the first cell of the user accessing the MN is the PCell, and if the link of the user and the PCell has problems, the user can not communicate with the MN (even if the link of the SCell has no problems). The change of SCell may not trigger the random access procedure of the user.

■ SCG (Secondary Cell Group ): a group of cells accessed by a user on the SN. Among the SCG cells, one is a special Cell (PSCell: primary SCell), and the other is a Secondary Cell of SCG (SCG SCell: SCG Secondary Cell). The change of the PSCell triggers the random access process of the user, and the first cell of the user accessing the SN is the PSCell, so if the link between the user and the PSCell is in problem, the user cannot communicate with the SN (even if the link between the SCG SCell has no problem). The change of SCG SCell may not trigger the random access procedure of the user.

A detailed description of the above concept can be found in ts36.300v14.2.0.

Under the MN and SN architectures, the radio bearers of a user include four types:

■ MCG Bearer (MCG Bearer): the data carried will be transmitted with users via MN, and the protocol layer for processing the data carried is all located in MN

■ MCG Split Bearer (MCG Split Bearer): the data of the bearer is transmitted to the user via the MN and the SN, but a PDCP (packet data convergence protocol) Layer for processing the data of the bearer is located at the MN, and other RLC (Radio link Control)/MAC (Medium Access Control)/PHY (Physical Layer) layers for processing the data of the bearer are located at both the MN and the SN.

■ SCG bearer (SCG bearer): the data of the bearer is transmitted with the user through the SN, and the protocol layers for processing the data of the bearer are all positioned at the SN

■ SCG split bearer (SCG split bearer): the data of the bearer will be transmitted with the user via the MN and SN, but the PDCP layer handling the data of such bearer is located at the SN, while there will be other protocol layers (RLC/MAC/PHY) on both the MN and SN that handle the data of such bearer.

A detailed description of the above concepts can be found in TS37.340.

The above concepts regarding cells and bearers are for one user.

In addition, in an NR (New Radio access) network or a fifth generation 5G network, in order to support network function virtualization, more efficient resource management and scheduling, a base station (e.g., a gNB) providing a wireless network interface for a terminal (UE) may be further divided into a central unit CU (central unit) and a distributed unit DU (distributed unit). The CU has at least Radio Resource Control (RRC) and Packet Data Convergence Protocol (PDCP) Protocol layers, and the like, and may also include a Service Data Adaptation Protocol (SDAP). The DU has a radio link control protocol (RLC), a Medium Access Control (MAC), a physical layer, and the like. Between CU and DU is a standardized public interface F1. The F1 interface is divided into a control plane F1-C and a user plane F1-U. The transport network layer of F1-C is based on IP transport. For more reliable signaling Transmission, a Stream Control Transmission Protocol (SCTP) Protocol is added over IP. The protocol of the application layer is F1AP. SCTP can provide reliable application layer message transport. The transport layer of the F1-U is UDP/IP (User data Protocol/Internet Protocol, user Datagram Protocol/Internet Protocol), and the GTP-U (GPRS tunneling Protocol for the User plane, GPRS tunneling Protocol) is used to carry a User plane Protocol data unit PDU over UDP/IP, where fig. 2 shows the structure of the CU and the DU.

In the above description, if there is an interface between two nodes (e.g. X2-U between MN and SN, F1-U between CU and DU, and X2-U between MN and DU) serving a user's user plane, a tunnel is established when the user's data is transmitted between the two nodes, and the tunnel corresponds to two addresses (address 1 and address 2), which are used by the two nodes for transmitting the user data, respectively, i.e. the user's data is sent from address 1 to address 2 or from address 2 to address 1.

In combination with the above-mentioned multi-connection and CU-DU separation techniques, the way in which the user connects to the network may be: the user accesses both the MN and the SN, and the SN comprises a CU and at least one DU connected to the CU, as shown in fig. 3. In this scenario, there is a possibility that the PSCell accessed by the user on the SN may change, and the reason for the change may be that the quality of the user in the current PSCell is not good, the load of the current PSCell is too heavy, and the like. Such changes may include, but are not limited to, the following:

■ The PSCell is changed from the current PSCell to an SCG SCell belonging to the same DU that has been configured to the user.

■ The PSCell is changed from the current PSCell to a cell belonging to the same DU, which is not configured to the user.

■ The PSCell is changed from the current PSCell to a cell belonging to another DU (the another DU and the DU where the current PSCell is located are both connected to the same CU, i.e., belong to the same SN), as shown in fig. 4.

■ The PSCell is changed from the current PSCell to a cell belonging to another DU (the other DU and the DU in which the current PSCell is located are both connected to different CUs, i.e., belong to different SNs), as shown in fig. 5.

When the PSCell change occurs, according to the LTE system, an SN modification procedure initiated by an SN node is triggered (in the procedure, a message received and sent by an SN is actually received and sent by a CU):

■ Step 1: the SN sends a secondary node modification required (SN modified required) message to the MN, which contains SCG Change Indication information (SCG Change Indication: this information indicates PSCell Change. In practice, this Indication message may also indicate other information) and SCG configuration information (SCG-Config, such as the configuration of the serving cell, SCG, of the user on the SN, possibly including RLC configuration, MAC layer configuration, etc.).

■ Step 2&3: these two steps are optional steps that are triggered when the MN is to provide the address for data forwarding and/or the encryption key of the new SN.

■ And 4, step 4: if the configuration of the PSCell change is successfully completed, the MN replies with an auxiliary node modification confirm (SN modification confirm) message to the SN.

The above process can be seen in ts36.300v14.2.0.

According to the existing mechanism, in the above step 1, the SCG change indication information and the SCG configuration information (SCG-Config) must be present at the same time, and if there is information on releasing the bearer in step 1, the SCG change indication information is not allowed to be present in step 1, that is, the existing mechanism does not support the change of the PSCell and the release of the bearer to occur at the same time.

Disclosure of Invention

The present invention aims to solve at least one of the above technical drawbacks, and in particular, the technical drawback of the existence of bearers to be released when a serving cell handover cannot be achieved.

According to an aspect, an embodiment of the present invention provides a method for switching a serving cell, including:

the auxiliary node sends an auxiliary node modification demand message to the main node, so that the main node switches a service cell according to the auxiliary node modification demand message and releases a bearer to be released;

and the auxiliary node receives an auxiliary node modification confirmation message returned by the main node aiming at the auxiliary node modification requirement message.

The embodiment of the invention also provides a method for switching a serving cell according to another aspect, which comprises the following steps:

the main node receives an auxiliary node modification demand message sent by an auxiliary node, switches a service cell according to the auxiliary node modification demand message and releases a bearer to be released;

and the master node returns a secondary node modification confirmation message aiming at the secondary node modification requirement message to the secondary node.

The embodiment of the present invention also provides an apparatus for switching a serving cell according to another aspect, including:

the first sending module is used for sending an auxiliary node modification demand message to the main node by the auxiliary node so that the main node switches a service cell according to the auxiliary node modification demand message and releases a bearer to be released;

and the first receiving module is used for receiving the auxiliary node modification confirmation message returned by the main node aiming at the auxiliary node modification requirement message by the auxiliary node.

a second receiving module, configured to receive, by the master node, an auxiliary node modification demand message sent by the auxiliary node, switch a serving cell according to the auxiliary node modification demand message, and release a bearer to be released;

and the second sending module is used for returning the auxiliary node modification confirmation message aiming at the auxiliary node modification requirement message to the auxiliary node by the main node.

The embodiment of the invention provides a method for switching a service cell, wherein an auxiliary node sends an auxiliary node modification demand message to a main node, so that the main node switches the service cell and releases a bearer to be released according to the auxiliary node modification demand message, a precondition guarantee is provided for releasing a user bearer on the auxiliary node when the service cell is switched according to the auxiliary node modification demand message subsequently, the auxiliary node receives an auxiliary node modification confirmation message returned by the main node aiming at the auxiliary node modification demand message, the service cell is switched and the bearer to be released on the auxiliary node is released according to the auxiliary node modification demand message when the service cell is switched, the signaling transmission efficiency is greatly improved, and signaling resources are saved.

Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

Drawings

The foregoing and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

FIG. 1 is a diagram of a network structure for UE multi-connection in the prior art;

fig. 2 is a block diagram of a base station concentration unit and a distribution unit in the prior art;

FIG. 3 is a diagram of a prior art network architecture in which a UE is connected to multiple connections including a centralized unit and a distributed unit;

FIG. 4 is a diagram of a prior art distributed unit for changing service subscribers;

FIG. 5 is a diagram illustrating a prior art method of changing a serving secondary node for a user;

FIG. 6 is a flowchart illustrating a method for handing over a serving cell according to a first embodiment of the present invention;

FIG. 7 is a flowchart illustrating a method for handing over a serving cell according to a second embodiment of the present invention;

FIG. 8 is a signaling flow diagram illustrating a process for changing a service distribution unit of a subscriber through a subscriber context setup procedure according to an embodiment of the present invention;

fig. 9 is a signaling flowchart illustrating a process of establishing a user context to change the configuration of a distribution unit of a user on the same secondary node according to an embodiment of the present invention;

fig. 10 is a signaling flowchart of a first method for modifying PSCell of a user on a distribution unit of a secondary node according to an embodiment of the present invention;

fig. 11 is a signaling flowchart of a second method for modifying PSCell of a user on a distribution unit of a secondary node according to an embodiment of the present invention;

fig. 12 is a signaling flowchart of a third method for modifying PSCell of a user on a distribution unit of a secondary node according to an embodiment of the present invention;

fig. 13 is a signaling flow diagram of secondary node modification triggered by a secondary node in an embodiment of the present invention;

FIG. 14 is a signaling flow diagram for user context establishment between a hub unit and a distribution unit in accordance with an embodiment of the present invention;

FIG. 15 is a signaling flow diagram of a centralized unit triggered modification of user context according to an embodiment of the present invention;

fig. 16 is a signaling flow diagram (two steps) of a first distribution unit triggered user context modification according to an embodiment of the present invention;

FIG. 17 is a signaling flow diagram (three or four steps) of the second distribution unit triggered user context modification according to the embodiment of the present invention

Fig. 18 is a schematic structural diagram of an apparatus for handing over a serving cell according to a third embodiment of the present invention;

fig. 19 is a schematic structural diagram of an apparatus for switching serving cells according to a fourth embodiment of the present invention.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are illustrative only and should not be construed as limiting the invention.

As used herein, the singular forms "a", "an", "the" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. It will be understood that when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element or intervening elements may also be present. Further, "connected" or "coupled" as used herein may include wirelessly connected or wirelessly coupled. As used herein, the term "and/or" includes all or any element and all combinations of one or more of the associated listed items.

It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the prior art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

As will be appreciated by those skilled in the art, a "terminal" as used herein includes both devices having a wireless signal receiver, which are devices having only a wireless signal receiver without transmit capability, and devices having receive and transmit hardware, which have devices having receive and transmit hardware capable of two-way communication over a two-way communication link. Such a device may include: a cellular or other communication device having a single line display or a multi-line display or a cellular or other communication device without a multi-line display; PCS (Personal Communications Service), which may combine voice, data processing, facsimile and/or data communication capabilities; a PDA (Personal Digital Assistant) which may include a radio frequency receiver, a pager, internet/intranet access, web browser, notepad, calendar and/or GPS (Global Positioning System) receiver; a conventional laptop and/or palmtop computer or other device having and/or including a radio frequency receiver. As used herein, a "terminal" or "terminal device" may be portable, transportable, installed in a vehicle (aeronautical, maritime, and/or land-based), or situated and/or configured to operate locally and/or in a distributed fashion at any other location(s) on earth and/or in space. As used herein, a "terminal Device" may also be a communication terminal, a web terminal, a music/video playing terminal, such as a PDA, an MID (Mobile Internet Device) and/or a Mobile phone with music/video playing function, or a smart tv, a set-top box, etc.

In a 5G network where a user is connected to both a MN and a SN, and the SN includes a CU and at least one DU connected to the CU, a change in PSCell may cause the release of the user bearer. For example, because a user moves and needs to change the PSCell of the user, such as from one DU (DU 1) to another DU (DU 2) connected to the same CU, the user is currently configured with one PSCell and multiple SCG scells in DU1, but only one cell on DU2 is suitable, so only one PSCell can be configured on DU2 for the user, in other words, in the process, the cell serving the user is changed from multiple cells on DU1 to one cell on DU2, and thus there may occur a situation where some bearers serving the user through the SNs have to be released. Such a scenario is that PSCell change occurs simultaneously with bearer release. Existing mechanisms do not support PSCell changes to occur simultaneously with bearer release. In addition, in order to support such a scenario, procedures for establishing and modifying a user context are also performed between the CU and the DU, and in these procedures, operations for establishing and modifying a context of a serving cell for a user need to be considered, which is not referred to in the existing discussion.

In addition, in a 5G network, a user is connected to both the MN and the SN, and the SN includes a CU and at least one DU connected to the CU. In this scenario, the user's PSCell may change while the user bearer on the SN may be released. To support this situation, the embodiment of the present invention provides a signaling interaction flow between the MN and the SN and a user context establishment and modification flow between the CU and the DU, which are described in detail as follows.

In order to solve the technical defect that there is a bearer to be released when a serving cell cannot be switched in the prior art, a first embodiment of the present invention provides a method for switching a serving cell, where a specific flow is shown in fig. 6, and includes: step 610, the secondary node sends a secondary node modification requirement message to the primary node, so that the primary node switches the serving cell according to the secondary node modification requirement message and releases the bearer to be released; and step 620, the secondary node receives a secondary node modification confirmation message returned by the primary node aiming at the secondary node modification requirement message.

Preferably, the secondary node modification requirement message comprises at least one of: the information of the bearer to be released, the indication information of the change of the SCG of the auxiliary cell group, the first indication information, the second indication information, the third indication information, the SCG configuration information and the information of the bearer which is not released.

Preferably, the information of the bearer to be released and the information of the bearer not to be released include at least one of: identification information of a bearer, qoS (quality of service) parameters of the bearer, type information of the bearer, tunnel address information of data transmitted between two nodes, a forwarding address of uplink data of the bearer and a forwarding address of downlink data of the bearer; the SCG change indication information is used for indicating the change of the SCG main cell PScell; the SCG configuration information is related configuration information which is generated by the auxiliary node and is about the SCG configured for the UE; the first indication information is used for indicating the main node to trigger the auxiliary node to send an auxiliary node modification request message to the auxiliary node; the second indication information is used for indicating the main node to forbid sending SCG configuration information to the user terminal UE; the third indication information is used for indicating that the auxiliary node forbids updating the SCG configuration information; the information of the unreleased bearers comprises information of each unreleased bearer and/or information of an unreleased master cell group MCG split bearer, and the information of the unreleased master cell group MCG split bearer comprises identification of the bearer and address information of a tunnel for transmitting data of the bearer on the side of the secondary node.

Preferably, after the step of sending the secondary node modification requirement message to the primary node, the method further includes: and the auxiliary node sends the SCG configuration information to the UE.

Preferably, before the step of the secondary node receiving the secondary node modification confirmation message returned by the primary node for the secondary node modification requirement message, the method further includes: receiving an auxiliary node modification request message sent by a main node; and sending a secondary node modification request confirmation message aiming at the secondary node modification request message to the primary node.

Preferably, the secondary node modification request message comprises at least one of: newly added bearing information, bearing information to be modified, bearing information to be released, encryption key information of an auxiliary node, SCG change indication information and information for configuring SCG, wherein the information for configuring SCG is information which is generated by a main node and requests UE to establish or modify or release SCG; the secondary node modification request acknowledgement message includes at least one of: the information of the accepted new bearer, the information of the accepted bearer to be modified, the information of the accepted bearer to be released, the SCG configuration information, and the information of the unreleased MCG split bearer.

Preferably, before the step of the secondary node sending the secondary node modification requirement message to the primary node, the method further includes: and the auxiliary node establishes the corresponding UE context or modifies the corresponding UE context.

Preferably, the secondary node includes a centralized unit CU and at least one distribution unit DU connected to the CU, and the step of the secondary node performing corresponding UE context establishment includes: sending a UE context establishment request message to the DU through the CU; and receiving a UE context establishment response message returned by the DU aiming at the UE context establishment request message through the CU.

Preferably, the UE context setup request message includes at least one of: cell list information, information of a newly added cell sent by a CU, context information related to UE bearing and/or identification, and reason information for establishing UE context; the UE context setup response message includes at least one of: the identification information of the cell which is not accepted, the context information related to the UE bearing and/or identification, the DU returns the reason information of the UE context establishment response message, and the information of the newly added cell sent by the DU; the cell list information includes at least one of: cell identity, measurement results of the cell; the information of the newly added cell sent by the CU comprises the information of the newly added cell determined by the CU or the information of the alternative newly added cell determined by the CU; the information of the newly added cell determined by the CU at least comprises one of the following items: cell list information, identification information of one or more PCell cells, identification information of one or more SCell cells, identification information of one or more PSCell cells, identification information of one or more SCG SCell cells, measurement information of a cell; the information of the candidate newly added cell determined by the CU includes at least one of: the method comprises the following steps of obtaining candidate cell list information, candidate identification information of one or more PCell cells, candidate identification information of one or more SCell cells, candidate identification information of one or more PSCell cells, candidate identification information of one or more SCG SCell cells and candidate measurement information of a new cell; the information of the newly added cell sent by the DU includes at least one of the following items: an identity of the selected PCell cell, an identity of the selected one or more SCell cells, an identity of the selected PSCell cell, an identity of the selected one or more SCG SCell cells; the context information related to the UE bearer and/or identity comprises at least one of the following information: user's carried information, user's identification information; the reason information for establishing the UE context and the reason information for returning the UE context establishment response message by the DU at least comprise one of the following information: cell overload, cell uplink overload, cell downlink overload, cell uplink control channel overload, load balance, signal quality or intensity difference of UE in a cell, and quality or intensity difference of UE in uplink or downlink signals of the cell; the reason information for establishing UE context and said DU return UE context establishment response message are for each cell or for all cells.

Preferably, the secondary node includes a central unit CU and at least one distribution unit DU connected to the CU, and the step of the secondary node performing corresponding UE context modification includes: sending a UE context modification request message to the DU through the CU; and receiving a UE context modification response message returned by the DU aiming at the UE context modification request message through the CU.

Preferably, the secondary node includes a central unit CU and at least one distribution unit DU connected to the CU, and the step of the secondary node performing corresponding UE context modification includes: sending a UE context modification requirement message to a CU through a DU; and receiving a UE context modification confirmation message returned by the CU for the UE context modification requirement message through the DU.

Preferably, the secondary node includes a central unit CU and at least one distribution unit DU connected to the CU, and the step of the secondary node performing corresponding UE context modification includes:

sending a UE context modification requirement message to a CU through a DU;

sending a UE context modification request message to the DU through the CU;

and receiving a UE context modification response message returned by the DU aiming at the UE context modification request message through the CU.

Preferably, after the step of receiving, by the CU, the UE context modification response message returned by the DU for the UE context modification request message, the method further includes:

and receiving a UE context modification confirmation message returned by the CU through the DU.

Compared with the prior art, the method for switching the service cell has the advantages that the auxiliary node sends the auxiliary node modification demand message to the main node, so that the main node switches the service cell and releases the bearer to be released according to the auxiliary node modification demand message, the premise guarantee is provided for releasing the user bearer on the auxiliary node when the service cell is switched according to the auxiliary node modification demand message subsequently, the auxiliary node receives the auxiliary node modification confirmation message returned by the main node aiming at the auxiliary node modification demand message, the service cell is switched and the bearer to be released on the auxiliary node is released according to the auxiliary node modification demand message when the service cell is switched, the signaling transmission efficiency is greatly improved, and the signaling resource is saved.

In addition, in order to solve the technical defect that there is a bearer to be released when a serving cell cannot be switched in the prior art, a second embodiment of the present invention further provides a method for switching a serving cell, where a specific flow is shown in fig. 7 and includes: step 710, the master node receives a secondary node modification demand message sent by the secondary node, switches a serving cell according to the secondary node modification demand message and releases a bearer to be released; and 720, the main node returns a secondary node modification confirmation message aiming at the secondary node modification requirement message to the secondary node.

The second embodiment of the present invention provides a method for switching a serving cell, which realizes that a master node can modify a demand message according to a received secondary node to switch the serving cell and release a bearer to be released on an SN when the serving cell is switched and the bearer to be released exists, thereby greatly improving signaling transmission efficiency and saving signaling resources.

The above embodiments of the present invention will be described in more detail in the following cases:

the above embodiments of the present invention mainly solve the following problems: when a user connects to both MN and SN, the primary cell PSCell of the user UE changes, and some bearers served by the SN need to be released for the user. The primary cell PSCell is a special cell PSCell used hereinafter, and the change of the PSCell may occur within the same DU or between different DUs. When the data transmission occurs between different DUs, the address of the tunnel (the tunnel between the MN and the DU) used for transmitting the data of the MCG split bearer changes. The names of the signaling in the signaling flow described below are only examples, and other names may be used. Some general information that will be used in the following description is described in a unified manner, as follows:

■ The bearer may be a newly added bearer, or a bearer to be modified, or a bearer to be released, or an accepted newly added bearer, or an accepted bearer to be modified, or an accepted bearer to be released, or a rejected newly added bearer, or a rejected bearer to be modified, or a rejected bearer to be released, and the bearer may include one or more of the following information:

■ Identification information of the bearer.

■ QoS parameters of the bearer, such as QoS Class Identifier (QoS Class Identifier), 5G QoS Indicator (5G QoS Identifier), allocation and Retention Priority (Allocation and Retention Priority), non-standardized QoS Flow descriptor (Non-standardized QoS Flow descriptor), etc. (see protocol TS36.423, protocol TS38.423 for details).

■ Bearer type information, such as MCG bearer, MCG split bearer, SCG split bearer.

■ The address information of the Tunnel used for transmitting the data carried between the two nodes, such as GTP Tunnel Endpoint information (GTP Tunnel Endpoint, see protocol TS 36.423), which includes Transport layer address information (Transport layer address, see protocols TS36.424, TS 36.414) and/or GTP Tunnel Endpoint Identifier (gtptunel Endpoint Identifier, see protocol TS 29.281). The two nodes may be respectively MN and SN, or a centralized unit of MN and SN, or a distributed unit of MN and SN, or a centralized unit and a distributed unit, and the address information is address information of one side node, such as MN, SN, a centralized unit of SN, a distributed unit of SN, a centralized unit of base station, a distributed unit of base station, and the like.

■ A forwarding address (UL forwarding GTP Tunnel Endpoint) of the uplink data of the bearer, for example, an address of the node side that sends the bearer information.

■ A forwarding address (DL forwarding GTP Tunnel Endpoint) of the downlink data of the bearer, for example, an address of the node side that sends the bearer information.

An Indication information of SCG Change (SCG Change Indication), which may indicate PSCell Change, or may indicate other contents, such as PDCPCountWrapAround (PDCP count wrap around), etc.

SCG configuration information (SCG-Config), which is related configuration information generated by the SN about SCGs configured for users, such as the configuration of pscells, the configuration of SCG scells, RLC configuration, MAC layer configuration, etc.

A message (SCG-ConfigInfo) for configuring SCG, which is generated by MN to request the user to set up, modify and release SCG, and also the MN provides some auxiliary information in this message to help SN generate SCG-Config.

In order to simplify the following description, unless otherwise specified, the specific contents of the carried information, the SCG change indication information, and the SCG configuration information (SCG-Config) are used to indicate the above information.

First, an example of a related signaling flow is given:

1) The PSCell and the new PSCell of the embodiment of the present invention belong to different DUs (UE context establishment procedure triggered by CU), as shown in fig. 8.

2) The PSCell and the new PSCell of the embodiment of the present invention belong to the same DU (UE context establishment procedure triggered by CU), as shown in fig. 9.

3) The PSCell and the new PSCell of the embodiment of the present invention belong to the same DU (UE context modification procedure triggered by CU), as shown in fig. 10.

4) The PSCell and the new PSCell of the embodiment of the present invention belong to the same DU (DU-triggered UE context modification procedure), as shown in fig. 11.

5) The signaling flow chart of the PSCell of the modified user on the distribution unit of the secondary node in the embodiment of the present invention is shown in fig. 12.

The signaling flow can be divided into two parts: a) Signaling flow between MN and SN (or centralized unit in SN); b) Signaling flow between the centralized unit and the distributed unit in the SN; these two parts are explained below:

signalling flow between A.MN and SN

Fig. 13 shows a signaling flow between the MN and the SN in fig. 8 to 12. The signaling procedure between MN and SN as described below is applicable not only to the signaling procedures shown in fig. 8 to 12, but also to other cases, such as the case of secondary node modification resulting in secondary node triggering.

Step 1: the auxiliary node (or auxiliary node-centralized unit) sends an auxiliary node modification required (SN modified required) message to the main node, wherein the message contains information of one or more of the following:

■ Information of bearers to be released;

■ SCG change indicating information indicating a change in PSCell;

■ New indication information indicating that the master node needs to trigger step 2;

■ Indication information without sending SCG configuration information (SCG-Config) to the user;

■ Indication information that the SCG configuration information (SCG-Config) does not need to be updated;

■ SCG configuration information (SCG-Config);

■ Information about each unreleased bearer, or about a portion of unreleased bearers (e.g., unreleased MCG split bearers). If the user is connected to both the MN and the SN (or the distribution unit of the SN), in this information, the address information refers to the address information on the SN side or the central unit side of the SN or the distribution unit side of the SN.

Step 2: the primary node sends a secondary node modification request (SN modification request) message to the secondary node (or secondary node-concentration unit), the message including one or more of the following information:

■ Newly added bearing information;

■ Information of the bearer to be modified;

■ Information of bearers to be released;

■ Encrypting key information of the secondary node;

■ Indication information of SCG change;

■ Message for configuring SCG (SCG-ConfigInfo).

And step 3: the secondary node (or secondary node-concentration unit) sends a secondary node modification request acknowledgement (SN modification request acknowledge) message to the primary node, the message containing information of one or more of:

■ Information of the accepted new bearer;

■ Information of the accepted bearer to be modified;

■ Information of the accepted bearer to be released;

■ SCG configuration information (SCG-Config);

and 4, step 4: the primary node sends a secondary node modification confirm (SN modification confirm) message, which may include a message (SCG-ConfigInfo) for configuring the SCG, to the secondary node (or secondary node-concentrator unit).

It should be noted that, among the above steps, steps 2 and 3 are optional steps. The conditions for triggering step 2 may be any of the following:

■ Step 1 comprises the indication information for triggering step 2;

■ The following information is contained in step 1:

■ Bearer information to be released, and

■ One or more of the following information:

SCG change indicating information indicating a change in the PSCell

SCG configuration information (SCG-Config)

Information about each unreleased bearer, or about a part of unreleased bearers (e.g. unreleased MCG split bearers). If the user is connected to both the MN and the SN (or the distribution unit of the SN), in this information, the address information refers to the address information on the SN side or the central unit side of the SN or the distribution unit side of the SN.

The above flow has several detailed embodiments (these detailed embodiments may trigger when the SN determines that the PSCell of the user has changed and has a bearer that needs to be released, the change of the PSCell occurs in the same distribution unit or in different distribution units, without excluding other trigger conditions).

The detailed embodiments are described in detail below.

Specifically, the specific procedure of the first detailed embodiment (including two steps, i.e. step 1 and step 4, and the MN sends SCG-Config to the user equipment UE) is as follows:

step 1: the secondary node (or secondary node-concentration unit) sends a secondary node modification required (SN modification required) message to the primary node, the message containing the following information:

■ Information of bearers to be released;

■ Optionally, SCG change indication information indicating that the PSCell is changed;

■ SCG configuration information (SCG-Config);

■ Optionally, the information carried by the unreleased MCG split includes at least the following information:

■ A carried identifier;

■ And the address information of the tunnel used for transmitting the carried data at the SN side or the SN distribution unit side.

Of the above information, the indication information of SCG change is an optional item, which may implicitly indicate that the PSCell of the user is to be changed by including information of an unreleased MCG split bearer and/or SCG configuration information (SCG-Config) in step 1.

Step 2/3: these two steps are not required.

And 4, step 4: the primary node sends a secondary node modification confirm (SN modification confirm) message to the secondary node (or secondary node-concentration unit).

The master node then sends the SCG configuration information (SCG-Config) received in step 1 to the user, which may be after step 1.

Specifically, the detailed procedure of the second embodiment (comprising two steps, i.e. step 1 and step 4, and the SN sends SCG-Config to the user equipment UE) is as follows:

■ Information of bearers to be released;

identification of bearers;

the address information of the tunnel used for transmitting the carried data at the SN side or the SN distribution unit side.

Of the above information, the indication information of SCG change is an optional item, which may implicitly indicate that the PSCell of the user is changed by including information of an unreleased MCG split bearer in step 1.

Step 2/3: these two steps are not required.

And 4, step 4: the primary node sends a secondary node modification confirm (SN modification confirm) message to the secondary node (or secondary node-concentrating unit).

Wherein the secondary node generates SCG configuration information (SCG-Config) before step 1 or between steps 1 and 4, and the secondary node transmits to the user after step 1.

Specifically, the detailed procedure of the third embodiment (including four steps, i.e., step 1 to step 4, and no SCG configuration information (SCG-Config) in step 1) is as follows:

■ Information of bearers to be released;

■ Optionally, SCG change indication information indicating that the PSCell is changed, or, optionally, new indication information indicating that the master node needs to trigger step 2;

■ A carried identifier;

Among the above information, the indication information of SCG change is an optional item, which may implicitly indicate that the PSCell of the user is changed by including information of unreleased MCG split bearers in step 1, or implicitly indicate that the master node needs to trigger step 2.

■ Newly added bearing information;

■ The information of the bearer to be modified may include bearer information obtained by modifying the bearer type of the bearer to be released in step 1;

■ Information of bearers to be released;

■ Encrypting key information of the secondary node;

■ Indication of SCG change;

■ Message for configuring SCG (SCG-ConfigInfo).

■ SCG configuration information (SCG-Config);

■ A carried identifier;

■ And the address information of the tunnel used for transmitting the loaded data at the SN side or the distribution unit side of the SN.

In the above steps, the SCG configuration information (SCG-Config) may be sent to the user by the secondary node, or may be sent to the user by the primary node. If the SCG configuration information is sent by the secondary node, in one embodiment, after step 1, the secondary node sends SCG configuration information (SCG-Config) (such as the SCG configuration information (SCG-Config) generated after step 2) to the user, and step 3 does not need to include SCG configuration information (SCG-Config). In still another embodiment, SCG configuration information (SCG-Config) is included in step 3, but the configuration information is transmitted by the secondary node, and the secondary node adds indication information indicating that the primary node does not need to transmit SCG configuration information (SCG-Config) in a secondary node modification request (SN modification request) message of step 1 or a secondary node modification request acknowledgement (SN modification request acknowledgement) message of step 3. If sent by the master node, in one embodiment, the SCG configuration information (SCG-Config) is included in step 3, and the master node sends the SCG configuration information (SCG-Config) received in step 3.

Specifically, the detailed procedure of the fourth embodiment (including four steps, i.e. step 1 to step 4, there is SCG configuration information (SCG-Config) in step 1 and the SCG-Config is updated in step 3) is as follows:

■ Information of bearers to be released;

■ SCG configuration information (SCG-Config);

■ A carried identifier;

Among the above information, the indication information of SCG change is an option, which may implicitly indicate that the PSCell of the user is to be changed by including information of an unreleased MCG split bearer and/or SCG configuration information (SCG-Config) in step 1, or implicitly indicate that the master node needs to trigger step 2.

■ Newly added load information;

■ Information of bearers to be released;

■ Encrypting key information of the secondary node;

■ Indication information of SCG change;

■ Message for configuring SCG (SCG-ConfigInfo).

■ SCG configuration information (SCG-Config);

■ A carried identifier;

and the address information of the tunnel used for transmitting the carried data at the SN side or the SN distribution unit side. And 4, step 4: the primary node sends a secondary node modification confirm (SN modification confirm) message to the secondary node (or secondary node-concentration unit).

In the above steps, the SCG configuration information (SCG-Config) may be sent to the user by the secondary node, or may be sent to the user by the primary node. One embodiment is that the secondary node will generate SCG configuration information (SCG-Config) after step 2, if sent by the secondary node, and step 3 need not include SCG configuration information (SCG-Config). In another embodiment, the secondary node first sends the SCG configuration information (SCG-Config) in step 1 to the user, and then sends the SCG configuration information (SCG-Config) generated after step 2 to the user. In another embodiment, SCG configuration information (SCG-Config) is included in step 3, but the configuration information is sent by the slave node after step 3, and the slave node adds indication information in a slave node modification request (SN modification request) message of step 1 or a slave node modification request acknowledgement (SN modification request acknowledgement) message of step 3, indicating that the master node does not need to send SCG configuration information (SCG-Config). If the master node transmits the SCG configuration information, in one embodiment, the SCG configuration information (SCG-Config) is included in step 3, and the master node transmits the SCG configuration information (SCG-Config) received in step 3. In still another embodiment, the master node first transmits the SCG configuration information (SCG-Config) in step 1, and then transmits the SCG configuration information (SCG-Config) received in step 3. The SCG configuration information (SCG-Config) in step 1 may also be sent by the primary node and the secondary node together, in one embodiment, the SCG configuration information (SCG-Config) generated after step 2 is sent by the secondary node; in another embodiment, the SCG configuration information (SCG-Config) in step 1 is transmitted by the secondary node, and the SCG configuration information (SCG-Config) generated after step 2 is transmitted by the primary node, and then the SCG configuration information (SCG-Config) is included in step 3.

Specifically, the detailed procedure of the fifth embodiment (including four steps, i.e., step 1 to step 4, there is SCG configuration information (SCG-Config) in step 1 and the SCG-Config is not updated in step 3) is as follows:

step 1: the secondary node (or secondary node-hub unit) sends a secondary node modification request (SN modification request) message to the primary node, the message containing the following information:

■ Information of bearers to be released;

■ SCG configuration information (SCG-Config);

■ A carried identifier;

Among the above information, the indication information of SCG change is an optional item, which may implicitly indicate that the PSCell of the user is to be changed by including information of unreleased MCG split bearers and/or SCG configuration information (SCG-Config) in step 1, or implicitly indicate that the master node needs to trigger step 2.

Step 2: the primary node sends a secondary node modification request (SN modification request) message to the secondary node (or secondary node-concentrating unit), the message including one or more of the following information:

■ Newly added load information;

■ Information of bearers to be released;

■ Encrypting key information of the secondary node;

■ Indication information of SCG change;

■ Message for configuring SCG (SCG-ConfigInfo).

And step 3: the secondary node (or secondary node-concentrating unit) sends a secondary node modification request acknowledgement (SN modification request acknowledge) message to the primary node, where the message does not contain SCG configuration information (SCG-Config), and optionally may contain information of an unreleased MCG split bearer.

In the above steps, SCG configuration information (SCG-Config) may be transmitted to the user by the secondary node, or SCG configuration information (SCG-Config) may be transmitted to the user by the primary node. If sent by the secondary node, in one embodiment, the secondary node may send after step 1/2/3/4, optionally, the secondary node may indicate to the primary node in step 1 or step 3 that the SCG configuration information (SCG-Config) need not be sent to the user. In another embodiment, SCG configuration information (SCG-Config) is included in step 3, but the configuration information is transmitted by the secondary node after step 3, and the secondary node adds indication information in a secondary node modification request acknowledgement (SN modification request acknowledge) message of step 3, indicating that the primary node does not need to transmit SCG configuration information (SCG-Config). If sent by the master node, one embodiment is that the master node sends the SCG configuration information (SCG-Config) received in step 1, possibly after step 1/2/3/4.

B. Signalling flow between central unit and distribution unit

The signaling flow comprises a user context establishing flow and a user context modifying flow. These two flows are respectively used in fig. 8 to fig. 12, but the user context establishing flow and the user context modifying flow described below are not limited to the flows in fig. 8 to fig. 12, and other situations that require the user context to be established and modified between the centralized node and the distributed node may also be used.

B-1. User context establishing process

The process comprises two steps, as shown in FIG. 14:

step 1: the centralized unit sends a user Context Setup Request (UE Context Setup Request) message to the distributed unit, where the message may include one or more of the following information:

■ Cell list information, the list comprising one or more cells, the information comprising

One or more of:

■ A cell identity;

■ Measurements of cells such as signal quality, signal strength, etc.

■ Information of newly added cells sent by CUs, which may be centralized units already

The determined new cell may be a new candidate cell, and the information includes information

One or more of:

■ Cell list information comprising identities of one or more cells;

■ Identification information of one or more PCell cells;

■ Identification information of one or more SCell cells;

■ Identification information of one or more PSCell cells;

■ Identification information of one or more SCG SCell cells;

■ Measurement information of the cell, such as signal quality, signal strength, etc.

■ Context related to user bearer and/or identification, such as information of the user's bearer, identification information of the user (such as the ID used by the user on the interface between the concentration unit and the distribution unit, e.g. the CU UE F1AP ID, which may be newly assigned by the CU, or already assigned to the user by the CU, or both).

■ And establishing reason information of the user context, wherein the information can be specific to each cell or all modifications, and possible reasons include one or more of cell overload, cell uplink or downlink overload, cell uplink control channel overload, load balance, signal quality or strength difference of a user in the cell, quality or strength difference of uplink or downlink signals of the user in the cell, and the like.

Step 2: the distribution unit will decide whether to accept the request of step 1 according to its own access control criteria, and then reply a user Context Setup Response (UE Context Setup Response) message to the central unit, where the message will include one or more of the following information:

■ Information of the newly added cell sent by the DU, which may contain one of the following information

Or a plurality of:

■ An identity of the selected PCell cell;

■ An identity of the selected one or more SCell cells;

■ An identity of the selected PSCell cell;

■ Identification of the selected one or more SCG SCell cells.

■ Identification information of an unacceptable cell, the unacceptable cell indicating unsuitability for configuring the cell to the user;

■ Context related to user bearers, such as information of the user's bearers;

■ The distribution unit may perform the above-mentioned replied reason information, which may be for each cell or for all modifications, and possible reasons include one or more of cell overload, cell uplink or downlink overload, cell uplink control channel overload, load balancing, quality or strength difference of signals of users in the cell, quality or strength difference of uplink or downlink signals of users in the cell, and the like.

The distribution unit establishes a context of the user according to the determined cell. In addition, if the distribution unit can accept the content of the cell configuration in the request message of step 1, the distribution unit may not include the information of the selected cell in the user Context Setup Response (UE Context Setup Response) message returned in step 2.

The information content contained in the two steps is different according to the decision maker of the user's cell configuration. The specific embodiments are as follows:

a. centralized unit deciding user's cell configuration

The UE Context Setup Request (UE Context Setup Request) message of step 1 contains one or more of the following:

■ Information of the newly added cell sent by the CU, the information comprising one or more of the following information:

■ Identification information of a PCell cell;

■ Identification information of one or more SCell cells;

■ Identification information of the PSCell cell;

■ Identification information of one or more SCG SCell cells;

■ Measurement information of the above-mentioned cell.

■ Context related to user bearer and/or identity, such as a message of the user's bearer, identification information of the user (such as an ID used by the user on the interface between the concentration unit and the distribution unit, e.g. a CU UE F1AP ID, which may be newly assigned by the CU, or already assigned to the user by the CU, or both);

The UE Context Setup Response (UE Context Setup Response) message of step 2 may contain one or more of the following:

■ Context related to user bearers, such as information of the user's bearers;

■ The distribution unit may perform the above replied reason information, which may be specific to each cell or may be specific to all modifications, and possible reasons include one or more of cell overload, cell uplink or downlink overload, cell uplink control channel overload, load balancing, signal quality or strength difference of a user in a cell, quality or strength difference of a user in a cell uplink or downlink signal, and the like.

In addition, if the distribution unit can accept the content of the cell configuration in the request message of step 1, the distribution unit may not include the information related to the cell (i.e., the identification information of the cell that is not accepted) and/or other information (i.e., the Context related to the user bearer, and the reason information for the distribution unit to reply) in the user Context Setup Response (UE Context Setup Response) message replied in step 2.

b. The distribution unit determines the cell configuration of the user and the concentration unit only provides the cell list

The user Context Setup Request (UE Context Setup Request) message of step 1 contains one or more of the following:

One or more of:

■ An identity of a cell;

■ Information of the newly added cell sent by the DU, the information comprising one or more of the following information:

■ Identification information of a PCell cell;

■ Identification information of one or more SCell cells;

■ Identification information of the PSCell cell;

■ Identification information of one or more SCG SCell cells.

■ Context related to user bearers, such as information of the user's bearers;

The cell included in step 2 may be a cell selected from the cell list given in step 1, or may be a cell not in the cell list given in step 1.

c. The distribution unit determines the cell configuration of the user and the concentration unit provides a list of alternative cells

The user Context Setup Request (UE Context Setup Request) message of step 1 contains one or more of the following information:

■ Information of the newly added candidate cell sent by the CU, the information comprising one or more of the following:

■ The alternative cell list information comprises the identification of one or more cells;

■ Identification information of one or more PCell cells which are alternative;

■ Identification information of one or more SCell cells that are alternative;

■ Identification information of one or more alternative PSCell cells;

■ Identification information of one or more SCG SCell cells;

■ Information of the newly added cell sent by the DU, which contains one or more of the following information:

■ Identification information of a PCell cell;

■ Identification information of one or more SCell cells;

■ Identification information of the PSCell cell;

■ Identification information of one or more SCG SCell cells.

■ Context related to user bearers, such as information of the user's bearers;

The cell included in step 2 may be a cell selected from the candidate cells given in step 1, or may be a cell that is not among the candidate cells given in step 1. In addition, if the distribution unit can accept the content of the cell configuration in the request message in step 1, the distribution unit may not include the above information about the cell (i.e. the information of the newly added cell sent by the DU, the identification information of the cell that is not accepted) and/or other information (i.e. the Context about the user bearer, the reason information for the above reply by the distribution unit) in the user Context Setup Response (UE Context Setup Response) message replied in step 2.

And B-2, a user context modification process, wherein the modification process can be triggered by a centralized unit or a distributed unit.

a. The centralized unit triggered cell configuration modification procedure includes two steps, as shown in fig. 15:

step 1: the central unit sends a user Context modification Request (UE Context Modified Request) message to the distribution unit, where the message may include one or more of the following information:

■ Cell list information, the list comprising one or more cells, the information comprising one or more of the following:

■ A cell identity;

■ Measurements of cells such as signal quality, signal strength, etc.

■ Information of the newly added serving cell, which may be the newly added cell already determined by the central unit, or an alternative newly added cell, sent by the CU, including one or more of the following information:

■ Cell list information comprising identities of one or more cells;

■ Identification information of one or more PCell cells;

■ Identification information of one or more SCell cells;

■ Identification information of one or more PSCell cells;

■ Identification information of one or more SCG SCell cells;

■ The information of the serving cell to be modified comprises one or more of the following information:

■ An identity of a PCell cell to be modified;

■ An identity of the SCell cell to be modified;

■ An identity of a PSCell cell to be modified;

■ Identification of SCG SCell cell to be modified;

■ Cell identity with changed cell type and indicating the type of the cell before and after modification: the identity of the cell that becomes SCell from PCell, the identity of the cell that becomes PCell from SCell, the identity of the cell that becomes SCG SCell from PSCell, the identity of the cell that becomes PSCell from SCG SCell;

■ Information of the serving cell to be released, such as a cell identity of the cell to be released;

■ And modifying the reason information of the user context, wherein the information can be specific to each cell or all the modifications, and possible reasons include one or more of cell overload, cell uplink or downlink overload, cell uplink control channel overload, signal quality or strength difference of a load balancing user in a cell, quality or strength difference of uplink or downlink signals of the user in the cell, and the like.

Step 2: the distribution unit sends a user Context Modified Response (UE Context Modified Response) message to the central unit, where the message may include one or more of the following information:

■ The received cell identifier of the new cell or the cell identifier of the new cell selected by the distribution unit, optionally, indicates the type of the new cell, such as PCell, SCell, PSCell, SCG SCell;

■ Cell identity of the newly added cell that is not accepted.

■ Information of the cell to be modified, the information comprising one or more of the following information:

■ Receiving the cell identification of the cell to be modified;

■ And the cell identification of the cell to be modified which is not accepted.

■ Information of the cell to be released, the information comprising one or more of the following information:

■ The received cell identification of the cell to be released;

■ Cell identities of cells to be released that are not accepted.

■ Context related to user bearers, such as information of the user's bearers;

■ The reason information for the above response may be for each cell or for all modifications, and possible reasons include one or more of cell overload, cell uplink or downlink overload, cell uplink control channel overload, signal quality or strength difference of load balancing users in a cell, quality or strength difference of uplink or downlink signals of users in a cell, and the like.

The newly added cell accepted in step 2 may be obtained from the cell list information or the newly added serving cell included in step 1, or may be another cell. The distribution unit modifies the context of the user according to the information in step 2. In addition, if the distribution unit can accept the content of the cell configuration in the request message in step 1, the distribution unit may not include the information about the cell (i.e., the information about the newly added cell sent by the DU, the information about the cell to be modified, and the information about the cell to be released) and/or other information (i.e., the Context about the user bearer, and the reason information for the distribution unit to perform the Response) in the user Context Modification Response (UE Context Modification Response) message returned in step 2.

b. The cell configuration modification procedure triggered by the distribution unit includes two steps, as shown in fig. 16:

step 1: the distribution unit sends a user Context Modified Required (UE Context Modified Required) message to the central unit, where the message may include one or more of the following information:

■ An identity of a PCell cell to be modified;

■ An identity of the SCell cell to be modified;

■ An identity of a PSCell cell to be modified;

■ The identification of the SCG SCell cell to be modified;

■ Cell identity where the cell type changes and indicates the type of the cell before and after modification: the identity of the cell that becomes SCell from PCell, the identity of the cell that becomes PCell from SCell, the identity of the cell that becomes SCG SCell from PSCell, the identity of the cell that becomes PSCell from SCG SCell;

■ Context related to user bearers, such as messages of the user's bearers;

■ And modifying the reason information of the user context, wherein the information can be specific to each cell or all the modifications, and possible reasons include one or more of cell overload, cell uplink or downlink overload, cell uplink control channel overload, load balance, signal quality or strength difference of a user in the cell, quality or strength difference of an uplink or downlink signal of the user in the cell, and the like.

Step 2: the central unit sends a user Context Modified Confirm (UE Context Modified Confirm) message to the distribution unit, which may include one or more of the following information:

■ Receiving the cell identification of the cell to be modified;

■ The received cell identification of the cell to be released;

■ Cell identities of cells to be released that are not accepted.

■ Context related to user bearers, such as information of the user's bearers;

■ The reason information of the response by the centralized unit may be for each cell or for all modifications, and possible reasons include one or more of cell overload, cell uplink or downlink overload, cell uplink control channel overload, load balancing, signal quality or strength difference of users in the cell, quality or strength difference of users in uplink or downlink signals in the cell, and the like.

If the concentration unit can accept the content of the cell configuration in the request message in step 1, the concentration unit may not include the information related to the cell (i.e. information of the cell to be modified, information of the cell to be released) and/or other information (i.e. Context related to the user bearer, and reason information for the concentration unit to perform the above response) in the user Context modification confirm (UE Context modification confirm) message returned in step 2.

c. The cell configuration modification process triggered by the distribution unit includes three or four steps, as shown in fig. 17:

■ An identity of a PCell cell to be modified;

■ An identity of the SCell cell to be modified;

■ An identity of a PSCell cell to be modified;

■ The identification of the SCG SCell cell to be modified;

■ Context related to user bearer, information of the user's bearer;

Step 2: the central unit sends a user Context modification Request (UE Context Modified Request) message to the distribution unit, where the message may include one or more of the following information:

■ A cell identity;

■ Measurements of cells such as signal quality, signal strength, etc.

■ Cell list information comprising identities of one or more cells;

■ Identification information of one or more PCell cells;

■ Identification information of one or more SCell cells;

■ Identification information of one or more PSCell cells;

■ Identification information of one or more SCG SCell cells;

■ An identity of a PCell cell to be modified;

■ An identity of the SCell cell to be modified;

■ An identity of the PSCell cell to be modified;

■ The identification of the SCG SCell cell to be modified;

■ And modifying the reason information of the user context, wherein the information can be specific to each cell or all the modifications, and possible reasons include one or more of cell overload, cell uplink or downlink overload, cell uplink control channel overload, signal quality or strength difference of a load balancing user in the cell, signal quality or strength difference of a user in the cell uplink or downlink, and the like.

The cell indicated by the cell related information in step 2 may or may not include the cell indicated by the cell related information included in step 1.

And step 3: the distribution unit sends a user Context Modified Response (UE Context Modified Response) message to the central unit, which may include one or more of the following information:

■ Cell identity of the newly added cell that is not accepted.

■ Receiving the cell identification of the cell to be modified;

■ The received cell identification of the cell to be released;

■ Cell identities of cells to be released that are not accepted.

■ Context related to user bearers, such as information of the user's bearers;

The newly added cell accepted in step 3 may be obtained from the cell list information or the newly added serving cell included in step 2, or may be another cell. The distribution unit modifies the context of the user according to the information in step 3. In addition, if the distribution unit can accept the content of the cell configuration in the request message in step 2, the distribution unit may not include the information about the cell (i.e. the information about the newly added cell sent by the DU, the information about the cell to be modified, the information about the cell to be released) and/or other information (i.e. the Context about the user bearer, and the reason information for the distribution unit to perform the Response) in the user Context Modification Response (UE Context Modification Response) message returned in step 3.

And 4, step 4: the central unit sends a user Context Modified Confirm (UE Context Modified Confirm) message to the distribution unit, which is an optional step that may include one or more of the following information:

■ Information of the newly added cell, the information comprising one or more of the following information:

■ Cell identification of the accepted newly added cell;

■ Cell identification of an unacceptable newly added cell

■ The received cell identification of the cell to be modified;

■ The received cell identification of the cell to be released;

■ Cell identities of cells to be released that are not accepted.

■ Context related to user bearers, such as information of the user's bearers;

The new cell and/or the cell to be modified and/or the cell to be released in step 4 may be obtained from the new cell and/or the serving cell to be modified and/or the serving cell to be released included in step 3, or may be another cell. The distribution unit modifies the context of the user according to the information in step 4. In addition, if the concentration unit can accept the content of the cell configuration in the response message of step 3, the concentration unit may not include the information related to the cell (i.e. information of the newly added cell, information of the cell to be modified, information of the cell to be released) and/or other information (i.e. Context related to the user bearer, information of the reason for the concentration unit to perform the above response) in the user Context modification confirm (UE Context modification confirm) message returned in step 4.

The third embodiment of the present invention further provides a device for switching a serving cell, as shown in fig. 18, including a first sending module S10 and a first receiving module S11.

A first sending module S10, configured to send, by the secondary node, a secondary node modification requirement message to the primary node, so that the primary node switches a serving cell according to the secondary node modification requirement message and releases a bearer to be released;

a first receiving module S11, configured to receive, by the secondary node, a secondary node modification confirmation message returned by the master node for the secondary node modification requirement message.

According to the device for switching the service cells, provided by the embodiment of the invention, the auxiliary node sends the auxiliary node modification demand message to the main node, so that the main node switches the service cells according to the auxiliary node modification demand message and releases the bearer to be released, a precondition guarantee is provided for releasing the user bearer on the auxiliary node when the service cells are switched according to the auxiliary node modification demand message subsequently, the auxiliary node receives the auxiliary node modification confirmation message returned by the main node aiming at the auxiliary node modification demand message, the service cells are switched according to the auxiliary node modification demand message and the bearer to be released on the auxiliary node is released when the service cells are switched, the signaling transmission efficiency is greatly improved, and the signaling resources are saved.

The fourth embodiment of the present invention further provides a device for switching a serving cell, as shown in fig. 19, including a second receiving module S13 and a second sending module S12.

A second receiving module S13, configured to receive, by the master node, an auxiliary node modification requirement message sent by the auxiliary node, switch the serving cell according to the auxiliary node modification requirement message, and release a bearer to be released;

a second sending module S12, configured to the master node return, to the slave node, a slave node modification acknowledgement message for the slave node modification requirement message.

According to the embodiment, when the serving cell is switched and the bearer to be released exists, the main node can switch the serving cell and release the bearer to be released on the auxiliary node according to the received auxiliary node modification demand message, so that the signaling transmission efficiency is greatly improved, and the signaling resources are saved.

Those skilled in the art will appreciate that the present invention includes apparatus directed to performing one or more of the operations described in the present application. These devices may be specially designed and manufactured for the required purposes, or they may comprise known devices in general-purpose computers. These devices have stored therein computer programs that are selectively activated or reconfigured. Such a computer program may be stored in a device (e.g., computer) readable medium, including, but not limited to, any type of disk including floppy disks, hard disks, optical disks, CD-ROMs, and magnetic-optical disks, ROMs (Read-Only memories), RAMs (Random Access memories), EPROMs (Erasable Programmable Read-Only memories), EEPROMs (Electrically Erasable Programmable Read-Only memories), flash memories, magnetic cards, or optical cards, or any type of media suitable for storing electronic instructions, and each coupled to a bus. That is, a readable medium includes any medium that stores or transmits information in a form readable by a device (e.g., a computer).

It will be understood by those within the art that each block of the block diagrams and/or flowchart illustrations, and combinations of blocks in the block diagrams and/or flowchart illustrations, can be implemented by computer program instructions. Those skilled in the art will appreciate that the computer program instructions may be implemented by a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, implement the features specified in the block or blocks of the block diagrams and/or flowchart illustrations of the present disclosure.

Those of skill in the art will appreciate that various operations, methods, steps in the processes, acts, or solutions discussed in the present application may be alternated, modified, combined, or deleted. Further, various operations, methods, steps in the flows, which have been discussed in the present application, may be interchanged, modified, rearranged, decomposed, combined, or eliminated. Further, steps, measures, schemes in the various operations, methods, procedures disclosed in the prior art and the present invention can also be alternated, changed, rearranged, decomposed, combined, or deleted.

The foregoing is only a partial embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.

Claims

1. A method performed by a network entity of a concentration unit, CU, corresponding to a secondary node, SN, in a wireless communication system, comprising:

sending a request message for requesting context establishment of a User Equipment (UE) to a network entity of a Distribution Unit (DU) corresponding to the SN, wherein the request message comprises first identification information of at least one candidate primary and secondary cell (PSCell) and second identification information of at least one secondary cell (SCell) to be established;

receiving a response message sent by a network entity corresponding to the DU for confirming context establishment of the UE, wherein the response message comprises third identification information of at least one SCell failed in establishment;

based on the response message, sending a message for requesting SN modification to a network entity corresponding to a master node MN associated with the SN.

2. The method of claim 1, wherein the message requesting SN modification comprises at least one of secondary cell group, SCG, configuration information, identification information of at least one bearer to be modified, and information of a tunnel endpoint at the SCG, the information of the tunnel endpoint being used for transmitting data of at least one bearer;

the method further comprises the following steps: receiving a message for acknowledging SN modification in response to the message for requesting SN modification from a network entity corresponding to the master node MN.

3. The method of claim 2, further comprising:

transmitting a message for requesting context modification of the UE to a network entity corresponding to the DU, the message for requesting context modification of the UE including fourth identification information of at least one SCell to be established;

receiving a message for confirming a context modification of the UE, which is transmitted by a network entity corresponding to the DU, wherein the message for confirming the context modification of the UE comprises fifth identification information of at least one SCell of which the establishment fails.

4. The method of claim 2, wherein the tunnel endpoint is configured to communicate downlink data of the at least one bearer to the UE.

5. The method of claim 1, wherein the response message confirming the context establishment of the UE further comprises a reason associated with at least one SCell for which the establishment failed, wherein the reason indicates that the SCell for which the DU establishment failed is overloaded.

6. The method of claim 3, wherein the message confirming the context modification of the UE further comprises a reason associated with at least one SCell that failed in establishment included in the message confirming the context modification of the UE, wherein the reason indicates that the SCell that failed in DU establishment is overloaded.

7. A network entity of a central unit CU corresponding to a secondary node SN, characterized in that it comprises: a transceiver configured to transmit and receive signals; and at least one processor configured to:

transmitting, by the transceiver, a request message for requesting context establishment of a User Equipment (UE) to a network entity of a Distribution Unit (DU) corresponding to the SN, the request message including first identification information of at least one candidate primary and secondary cell (PSCell) and second identification information of at least one secondary cell (SCell) to be established;

receiving, by the transceiver, a response message transmitted by a network entity corresponding to the DU for confirming context establishment of the UE, the response message including third identification information of at least one SCell for which establishment failed;

sending, by the transceiver, a message requesting SN modification based on the response message to a network entity corresponding to a master node MN associated with the SN.

8. The CU of claim 7, wherein the message requesting SN modification comprises at least one of secondary cell group, SCG, configuration information, an identification of at least one bearer to be modified, and address information of a tunnel endpoint at the SCG for transmitting data of the at least one bearer;

the at least one processor is further configured to: by receiving a message for acknowledging SN modification of the master node MN in response to the message for requesting SN modification.

9. The network entity according to claim 8, wherein the at least one processor is further configured to:

transmitting, by the transceiver, a message for requesting context modification of the UE to a network entity corresponding to the DU, the message for requesting context modification of the UE including fourth identification information of at least one SCell to be established;

receiving, by the transceiver, a message for confirming a context modification of the UE, which is transmitted by a network entity corresponding to the DU, the message for confirming the context modification of the UE including fifth identification information of the at least one SCell of which establishment failed.

10. The network entity according to claim 8, wherein the tunnel endpoint is configured to communicate downlink data of the bearer to the UE.

11. The network entity according to claim 7, wherein the response message confirming the context establishment of the UE further comprises a reason associated with at least one SCell that failed in the establishment, wherein the reason indicates that the SCell that failed in the DU establishment is overloaded.

12. The network entity according to claim 9, wherein the message confirming context modification for the UE further comprises a reason associated with at least one SCell with failed establishment included in the message confirming context modification for the UE, wherein the reason indicates that the SCell with failed DU establishment is overloaded.

13. A network entity of a distribution unit, DU, corresponding to a secondary node, SN, comprising:

a transceiver configured to transmit and receive signals; and

at least one processor configured to:

receiving, by the transceiver, a request message for requesting context establishment of a UE, the request message being sent by a network entity of a CU corresponding to the SN, the request message including first identification information of at least one candidate primary-secondary cell PSCell and second identification information of at least one secondary cell SCell to be established;

transmitting, by the transceiver, a response message to a network entity corresponding to the CU for confirming a context establishment of the UE, the response message including third identification information of the at least one SCell whose establishment failed;

wherein the message for requesting SN modification based on the response message is sent by a network entity corresponding to the CU to a network entity corresponding to a master node MN associated with the SN.

14. The network entity corresponding to the DU of claim 13, wherein the message for requesting SN modification includes at least one of secondary cell group, SCG, configuration information, an identification of at least one bearer to be modified, and address information of a tunnel endpoint at the SCG, the address information of the tunnel endpoint being used for transmitting data of the at least one bearer; the message for acknowledging SN modification in response to the message for requesting SN modification is transmitted to a network entity corresponding to the CU through a network entity corresponding to the master node MN.

15. The network entity according to claim 14, wherein the at least one processor is further configured to:

receiving, by the transceiver, a message for requesting context modification of a UE, which is transmitted by a network entity corresponding to the CU, the message for requesting context modification of the UE including fourth identification information of at least one SCell to be established;

transmitting, by the transceiver, a message for confirming a context modification of the UE to a network entity corresponding to the CU, the message for confirming the context modification of the UE including fifth identification information of the at least one SCell whose establishment failed.

16. The network entity corresponding to the DU of claim 14, wherein the tunnel endpoint is configured to communicate downlink data of the bearer to the UE.

17. The DU of claim 13, wherein the response message confirming context establishment for the UE further comprises a reason associated with at least one SCell with failed establishment, wherein the reason indicates that the SCell with failed DU establishment is overloaded.

18. The network entity according to claim 15, wherein the message for confirming the context modification of the UE further comprises a cause associated with at least one SCell with failed establishment included in the message for confirming the context modification of the UE, wherein the cause indicates that the SCell with failed DU establishment is overloaded.

19. A User Equipment (UE), comprising:

a transceiver configured to transmit and receive signals; and at least one processor configured to:

the UE communicates with a network entity corresponding to a main node MN and an auxiliary node SN;

sending a request message for confirming context establishment of UE to a network entity of a DU corresponding to the SN through a network entity of the CU corresponding to the SN, wherein the request message comprises first identification information of at least one candidate primary and secondary cell PSCell and second identification information of at least one to-be-established secondary cell SCell; a response message for confirming context establishment of the UE, the response message including third identification information of at least one SCell of which establishment failed;

a message for requesting SN modification based on the response message is sent by a network entity corresponding to the CU to a network entity corresponding to a master node MN associated with the SN.

20. The UE of claim 19, wherein the message requesting SN modification comprises at least one of secondary cell group, SCG, configuration information, an identification of at least one bearer to be modified, and address information of a tunnel endpoint at the SCG, the address information of the tunnel endpoint being used to transmit data of the at least one bearer; a message for acknowledging SN modification in response to the message for requesting SN modification is sent to a network entity corresponding to the CU through a network entity corresponding to the MN.

21. The UE of claim 20, wherein a UE context modification request message is sent by a network entity corresponding to the CU to a network entity corresponding to the DU, and wherein the UE context modification request message comprises fourth identification information of at least one SCell to be established; and sending a UE context modification response message to a network entity corresponding to the CU through the network entity corresponding to the DU, wherein the UE context modification response message comprises fifth identification information of at least one SCell which fails to be established.

22. The UE of claim 20, wherein the tunnel endpoint is configured to communicate downlink data of the bearer to the UE.

23. The UE of claim 19, wherein the response message confirming the context establishment of the UE further comprises a reason associated with at least one SCell with failed establishment, and wherein the reason indicates that the SCell with failed DU establishment is overloaded.

24. The UE of claim 21, wherein the message confirming the context modification of the UE further comprises a reason associated with at least one SCell with failed establishment included in the message confirming the context modification of the UE, wherein the reason indicates that the SCell with failed DU establishment is overloaded.

25. A method performed by a network entity of a distribution unit, DU, corresponding to a secondary node, SN, in a wireless communication system, comprising:

receiving a request message sent by a network entity of a CU corresponding to the SN and used for requesting context establishment of UE, wherein the request message comprises first identification information of at least one candidate primary and secondary cell PSCell and second identification information of at least one to-be-established secondary cell SCell;

transmitting a response message for confirming context establishment of the UE to a network entity corresponding to the CU, wherein the response message comprises third identification information of at least one SCell failed in establishment;

wherein the message for requesting SN modification based on the response message is sent by the network entity corresponding to the CU to the network entity corresponding to the master node MN associated with the SN.

26. The method of claim 25, wherein the message requesting SN modification comprises at least one of secondary cell group, SCG, configuration information, an identification of at least one bearer to be modified, and address information of a tunnel endpoint at the SCG, the address information of the tunnel endpoint being used for transmitting data of the at least one bearer; the message for acknowledging SN modification in response to the message for requesting SN modification is transmitted to a network entity corresponding to the CU through a network entity corresponding to the master node MN.

27. The method of claim 26, further comprising:

receiving a message for requesting context modification of the UE, which is sent by a network entity corresponding to the CU, wherein the message for requesting the context modification of the UE comprises fourth identification information of at least one SCell to be established;

transmitting a message for confirming a context modification of the UE to a network entity corresponding to the CU, wherein the message for confirming the context modification of the UE comprises fifth identification information of at least one SCell of which the establishment fails.

28. The method of claim 26, wherein the tunnel endpoint is configured to communicate downlink data of the bearer to the UE.

29. The method of claim 25, wherein the response message confirming the context establishment of the UE further comprises a reason associated with at least one SCell with failed establishment, wherein the reason indicates that the SCell with failed DU establishment is overloaded.

30. The method of claim 27, wherein the message confirming the context modification for the UE further comprises a cause associated with at least one SCell with failed establishment included in the message confirming the context modification for the UE, wherein the cause indicates that the SCell with failed DU establishment is overloaded.