CN108307539B - Link reestablishment method, first base station, second base station, user equipment and device - Google Patents

Abstract

The invention discloses a link reconstruction method, a first base station, a second base station, user equipment and a device, which are used for improving the success rate of link reconstruction and ensuring the continuity of bearer in the reconstruction process, including the first base station receiving user equipment The re-establishment request sent by the first base station when the re-establishment of the link is rejected; when the first base station determines that the re-establishment request contains the second re-establishment context information, the first base station re-establishes the second re-establishment context information. The context information is sent to the second base station; when the first base station receives the acknowledgment information sent by the second base station, the first base station sends a first reestablishment rejection message to the user equipment, wherein the acknowledgment information It is determined by the second base station that the user equipment can re-establish a link through the second base station according to the second re-establishment context information, and the first re-establishment rejection message includes the confirmation information.

Description

Link reestablishment method, first base station, second base station, user equipment and device

technical field

The present invention relates to the field of communication technologies, and in particular, to a link re-establishment method, a first base station, a second base station, user equipment and a device.

Background technique

With the continuous development of communication technology, users need the network to provide more convenient and faster high-traffic data communication services. In order to meet this demand of users, the communication network architecture needs continuous evolution and enhancement. The 3rd Generation Partnership Project (3GPP) proposed in R12 a network architecture in which several micro base stations are added within the coverage of a macro base station, that is, a dual-connection/multi-connection system architecture. In this system architecture, the user equipment can maintain connections with two (or more) base stations at the same time to perform uplink and downlink communications. The two (or multiple base stations) that are connected to the user equipment at the same time include at least one master base station (Master eNB, MeNB) and at least one secondary base station (Secondary eNB, SeNB. The MeNB is used to manage the SeNB in the system.

When the user equipment is in a radio resource control (Radio Resource Control, RRC) connection state, if a handover failure, radio link failure, integrity protection failure, or RRC reconfiguration failure occurs, the RRC connection re-establishment process will be triggered. RRC connection re-establishment, including Signalling Radio Bearer (SRB1) operation recovery, and safe reactivation. The user equipment in the RRC connected (RRC_CONNECTED) state, if the security has been activated, may initiate this process to continue the RRC connection. Re-establishment succeeds only when the relevant cell has a terminal context.

In the existing protocol or solution, if the user equipment triggers the reestablishment process on the MeNB, once the user equipment receives the RRC Connection Reestablishment Reject message, the user equipment enters the leaving RRC_CONNECTED process, and the data bearer is interrupted. At this time, even if a cell that meets the requirement exists in the SeNB, no attempt is made to perform re-establishment on the SeNB. On the other hand, if the user equipment triggers the reestablishment process on the SeNB, once it receives the RRC Connection Reestablishment Reject, it will directly enter the leaving RRC_CONNECTED process, and the data bearer will be interrupted. to rebuild. As a result, the success rate of link re-establishment is low, and the continuity of the bearer cannot be guaranteed.

SUMMARY OF THE INVENTION

The present invention provides a method for link reconstruction, including a first base station, a second base station, user equipment and devices, which are used to improve the success rate of link reconstruction and ensure the continuity of bearer in the reconstruction process.

A link re-establishment method, comprising: a first base station receiving a re-establishment request sent by a user equipment when re-establishing a link through the first base station is rejected; the first base station determines that the re-establishment request includes a second re-establishment context information, the first base station sends the second reestablished context information to the second base station; when the first base station receives the confirmation information sent by the second base station, the first base station sends the user The device sends a first re-establishment rejection message, wherein the confirmation information is that the second base station determines according to the second re-establishment context information that the user equipment can re-establish a link through the second base station, and the first re-establishment The confirmation message is included in the rejection message.

It also includes: when the first base station determines that the re-establishment request does not contain second re-establishment context information, the first base station sends a second re-establishment reject message to the user equipment, wherein the second re-establishment reject message It is used to notify the user equipment to refuse to perform link re-establishment.

The first base station is a primary base station, the second base station is a secondary base station, and the first base station manages the second base station.

Before the first base station receives the reestablishment request sent by the user equipment when the user equipment refuses to re-establish the link through the first base station, the method further includes: the first base station determines whether the user equipment is re-established through the first base station for the first time link; if the judgment result is yes, the first base station receives the re-establishment request sent by the user equipment when the user equipment refuses to re-establish the link through the first base station.

A link re-establishment method, comprising: a second base station receiving second re-establishment context information sent by a first base station; and the second base station determining, according to the second re-establishment context information, that the user equipment can re-establish When the link is established, the second base station sends confirmation information to the first base station.

A link re-establishment method, comprising: user equipment re-establishing a link through the first base station; sending a re-establishment request when the user equipment is rejected by the first base station, where the re-establishment request includes second re-establishment context information .

Before sending the re-establishment request when the user equipment is rejected by the first base station, the method further includes: determining, by the user equipment, whether it is the first time to re-establish a link through the first base station; if the determination result is yes, the user equipment A second reconstruction context information is determined.

A link re-establishment method, comprising: user equipment determining whether a link is re-established through the first base station for the first time; if the determination result is yes, the user equipment determines second re-establishment context information; The first base station sends a second UE indication message, wherein the second UE indication message includes the second re-establishment context information.

The first base station is a primary base station; or the first base station is a secondary base station.

A first base station, comprising: a receiving module for receiving a re-establishment request sent by a user equipment when re-establishing a link through the first base station is rejected; a sending module for determining that the re-establishment request includes a second When the context information is reconstructed, the second reconstruction context information is sent to the second base station; when the confirmation information sent by the second base station is received, a first reconstruction rejection message is sent to the user equipment, wherein the confirmation The information is that the second base station determines that the user equipment can re-establish a link through the second base station according to the second re-establishment context information, and the first re-establishment rejection message includes the confirmation information.

The sending module is further configured to send a second reconstruction rejection message to the user equipment when it is determined that the reconstruction request does not contain the second reconstruction context information, wherein the second reconstruction rejection message is used to notify the rejection The user equipment performs link re-establishment.

The receiving module is further configured to judge whether the user equipment re-establishes the link through the first base station for the first time; if the judgment result is yes, receive the message sent when the user equipment refuses to re-establish the link through the first base station. Rebuild request.

A second base station, comprising: a receiving module for receiving second re-establishment context information sent by a first base station; a sending module for determining, according to the second re-established context information, that the user equipment can pass the second base station When the link is re-established, the second base station sends confirmation information to the first base station.

A user equipment, comprising: an execution module for re-establishing a link through a first base station; a sending module for sending a re-establishment request when the user equipment is rejected by the first base station, where the re-establishment request includes a first 2. Reconstruct the context information.

The executing module is further configured to determine whether the link is re-established through the first base station for the first time; if the determination result is yes, determine the second re-establishment context information.

A link re-establishment device, comprising: a determination module for determining whether a link is re-established through the first base station for the first time; an execution module for determining second reconstruction context information if the determination result is yes; The first base station sends a second UE indication message, wherein the second UE indication message includes the second re-establishment context information.

By adopting the above technical solution, when receiving a re-establishment request sent by the user equipment when the re-establishment of the link is rejected, when it is determined that the re-establishment request contains second re-establishment context information, the second re-establishment context information is sent to a second base station; when the first base station receives the confirmation information sent by the second base station, the first base station sends a first reestablishment rejection message to the user equipment, where the confirmation information is the first re-establishment rejection message. The second base station determines that the user equipment can re-establish a link through the second base station according to the second re-establishment context information, and the first re-establishment rejection message includes the confirmation information, which is used to improve the success rate of link re-establishment , to ensure the continuity of the bearer during the reconstruction process.

Description of drawings

FIG. 1 is a flowchart of a proposed link re-establishment method in Embodiment 1 of the present invention;

FIG. 2 is a flowchart of a proposed link re-establishment method in Embodiment 2 of the present invention;

FIG. 3 is a flowchart of a proposed link re-establishment method in Embodiment 3 of the present invention;

FIG. 4 is a schematic diagram of the structural composition of the first base station proposed in Embodiment 4 of the present invention;

FIG. 5 is a schematic diagram of the structural composition of the second base station proposed in Embodiment 4 of the present invention;

FIG. 6 is a schematic diagram of the structural composition of the proposed user equipment in Embodiment 4 of the present invention;

FIG. 7 is a schematic structural diagram of the proposed link re-establishment apparatus in Embodiment 4 of the present invention.

Detailed ways

Under normal circumstances, RRC connection re-establishment initialization is triggered when any of the following conditions occur: radio link failure is detected; handover failure; Evolved Universal Terrestrial Radio Access (E-UTRA) side mobility failure ; The underlying system integrity check failed; RRC connection reconfiguration failed. During the initialization phase of the user equipment re-establishing the connection (referred to as re-establishment), it will start and stop some timers (such as stop T310, start T311), and suspend all radio link bearers (Radio Bear, RB) except SRB0. Perform default configuration for layer one layer two, cell selection, etc. After the connection re-establishment is triggered, the user equipment will start and stop some timers (for example, stop T311, start T301), initialize the RRC Connection Reestablishment Request message, and send it to the target cell through the random access process in the contention mode.

After receiving the re-establishment request, if the target cell retains the context information of the user equipment, it determines whether to accept the re-establishment request of the user equipment according to its own algorithm. If the target cell allows the user equipment to reestablish, it will send an RRCConnection Reestablishment message to the device. After receiving the message, the user equipment starts and stops related timers according to the configuration in the message, restores SRB1, reactivates security, integrity protection and encryption, and performs related measurements. After completing these processes, the user equipment sends an RRC Connection Reestablishment Complete message to notify the completion of the network reestablishment. If the target cell does not have the context information of the user equipment, or according to its own algorithm, the user equipment is not allowed to perform reconstruction, it will send an RRC Connection Reestablishment Reject message to the user equipment. After receiving the message, the user equipment enters the process of leaving RRC_CONNECTED.

As can be seen from the above, in the existing protocol or solution, if the user equipment triggers the reestablishment process on the MeNB, once the user equipment receives the RRC Connection Reestablishment Reject message, the user equipment will enter the leaving RRC_CONNECTED process, and the data bearer will be interrupted. Even if a target cell that meets the requirements exists in the SeNB, the user equipment will not attempt to perform re-establishment on the SeNB. Conversely, if the hand-held device triggers the reestablishment process on the SeNB, once the RRC Connection Reestablishment Reject is received, it will directly enter the leaving RRC_CONNECTED process, and the data bearer will be interrupted. Even if there is a target cell that meets the requirements in the MeNB, it will not attempt to Rebuild on the MeNB.

In the technical solutions proposed in the examples of the present invention, for ease of explanation, the base stations are distinguished as the first base station and the second base station, the first base station may be the MeNB, and the second base station may be the SeNB. Wherein, by adding confirmation information in the RRC ConnectionReestablishment Reject message, the success rate of link re-establishment is improved, thereby ensuring the continuity of the bearer.

The main implementation principles, specific implementations and corresponding beneficial effects of the technical solutions of the embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

Example 1

Embodiment 1 of the present invention proposes a link re-establishment method, as shown in FIG. 1 , and its specific processing flow is as follows:

Step 11: The first base station receives a reestablishment request sent by the user equipment when the link reestablishment through the first base station is rejected.

In this case, the first base station may be the MeNB or the SeNB.

The user equipment sends a re-establishment request through the first base station to re-establish the link.

Step 12, the first base station determines whether the received reconstruction request contains the second reconstruction context information. If the determination result is yes, step 13 is performed; otherwise, if the determination result is no, step 14 is performed.

Wherein, the second reconstruction context information includes user equipment context information, cell radio network temporary identifier (Cell Radio Network Temporary Identifier, c-RNTI), physical cell identifier (physCellId), short message integrity authentication code authentication code (Short Message Authentication Code for Integrity, shortMAC-I) and the reason for rebuilding, etc. For details, please refer to Table 1 below.

Table 1

Step 13, when the first base station determines that the re-establishment request includes the second re-establishment context information, the first base station sends the second re-establishment context information to the second base station.

Wherein, in this step, if the first base station is the MeNB, the second base station may be the SeNB. If the first base station is a SeNB, the second base station may be a MeNB.

Step 131, the second base station receives the second reconstruction context information sent by the first base station.

Step 132, the second base station determines whether the user equipment can re-establish the link through the second base station according to the second re-establishment context information, and if the determination result is yes, step 133 is performed, otherwise, the process ends.

Step 133, the second base station sends confirmation information to the first base station.

Step 134, the first base station receives the confirmation information.

Step 135: The first base station sends a first reestablishment rejection message including confirmation information to the user equipment.

In the technical solution proposed in the embodiment of the present invention, for the convenience of explanation, the reconstruction rejection message is distinguished from the first reconstruction rejection message and the second reconstruction rejection message, wherein the first reconstruction rejection message is the existing reconstruction rejection message in the existing reconstruction rejection message. Confirmation information for instructing the user equipment to perform secondary re-establishment on the MeNB/SeNB is added in . When constructing the first reconstruction rejection message, the first reconstruction rejection information may be set as follows. The reestablishment second is used to indicate whether the user equipment can perform secondary re-establishment on the MeNB/SeNB.

RRCConnectionReestablishmentReject-r8-IEs::=SEQUENCE{

reestablishmentSecondly BOOLEAN OPTIONAL,

nonCriticalExtension RRCConnectionReestablishmentReject-v8a0-IEsOPTIONAL

}

Step 136, the user equipment receives the first re-establishment rejection message including the confirmation information, and re-establishes the connection through the second base station.

Step 14, when the first base station determines that the re-establishment request does not contain the second re-establishment context information, the first base station sends a second re-establishment rejection message to the user equipment.

The second re-establishment rejection message is used to notify the user equipment to reject the link re-establishment.

In step 15, the user equipment enters the process of leaving RRC_CONNECTED, and the data bearer is interrupted.

Optionally, in the above processing flow, before the first base station receives the re-establishment request sent by the user equipment when the user equipment rejects the link re-establishment through the first base station, the method further includes:

The first base station determines whether the user equipment re-establishes the link through the first base station for the first time, and if the determination result is yes, the first base station receives the re-establishment request sent by the user equipment when the link re-establishment through the first base station is rejected.

In the technical solution proposed above in Example 1 of the present invention, in the specific implementation, when the user equipment refuses to re-establish on the MeNB/SeNB, if it is determined that the re-establishment request carries the second re-establishment context information, the second re-establishment context information of the user equipment is used. Notify the SeNB/MeNB. After receiving the request, the SeNB/MeNB determines whether to allow the user equipment to reestablish and notifies the MeNB/SeNB. The MeNB/SeNB indicates in the reestablishment reject message whether the user equipment can initiate the second reestablishment on the SeNB/MeNB.

When the MeNB/SeNB rejects the re-establishment of the user equipment after a certain judgment, the MeNB/SeNB makes a judgment according to whether the re-establishment request sent by the user equipment carries the second re-establishment context information. If the second reconstruction context information is not carried, the user equipment is notified through a reconstruction rejection message that the second reconstruction cannot be initiated, and the user equipment enters the process of leaving RRC_CONNECTED. Otherwise, the MeNB/SeNB notifies the SeNB/MeNB of the second re-establishment context information of the user equipment. After receiving the notification message, the SeNB/MeNB determines whether to allow the re-establishment, and notifies the MeNB/SeNB in the re-establishment confirmation message. The MeNB/SeNB informs the user equipment whether the re-establishment on the SeNB/MeNB can be initiated in the re-establishment reject message.

By adding the second reconstruction context information in the reconstruction request, it is ensured that the user equipment can perform secondary reconstruction in the corresponding base station, which can improve the success rate of reconstruction and ensure the continuity of the bearer.

Embodiment 2

The second embodiment of the present invention proposes a link reconstruction method, as shown in FIG. 2 , and its specific processing flow is as follows:

Step 21, the user equipment determines to re-establish the link through the first base station.

In this case, the first base station may be the MeNB or the SeNB.

Step 22, the user equipment determines and sends the indication information of the second user equipment.

Wherein, the indication information of the second user equipment includes relevant information of the second base station.

Specifically, the related information of the second base station may be the second reconstruction context information. For the second reconstruction context information, please refer to the detailed description of Table 1 in the above-mentioned first embodiment.

In a specific implementation, the reconstruction request can be implemented in the following ways:

Embodiment 3

Embodiment 3 of the present invention proposes a link re-establishment method, as shown in FIG. 3 , and its specific processing flow is as follows:

Step 31, the user equipment determines whether the link is re-established through the first base station for the first time. If the judgment result is yes, step 32 is executed, otherwise, if the judgment result is no, step 34 is executed.

Step 32, if the determination result is yes, the user equipment determines the second reconstruction context information.

Step 33, the user equipment sends a second UE indication message to the first base station.

The second UE indication message includes the second reconstruction context information.

Step 34, the user equipment sends a second UE indication message that does not include the second re-establishment context information to the first base station.

Embodiment 4

Embodiment 4 of the present invention proposes a first base station, as shown in FIG. 4 , including:

The receiving module 401 is configured to receive a reestablishment request sent by the user equipment when the link reestablishment through the first base station is rejected.

The sending module 402 is configured to send the second reconstruction context information to a second base station when it is determined that the reconstruction request contains the second reconstruction context information; when receiving the confirmation information sent by the second base station, Send a first re-establishment rejection message to the user equipment, wherein the confirmation information is that the second base station determines that the user equipment can re-establish a link through the second base station according to the second re-establishment context information, so The confirmation information is included in the first reconstruction rejection message.

Optionally, the above sending module 402 is further configured to send a second reconstruction rejection message to the user equipment when it is determined that the reconstruction request does not contain the second reconstruction context information, wherein the second reconstruction rejection message uses Rejecting the user equipment to perform link re-establishment upon notification.

Optionally, the above receiving module 401 is further configured to judge whether the user equipment re-establishes the link through the first base station for the first time; if the judgment result is yes, the receiving user equipment re-establishes the link through the first base station Rebuild request sent when rejected.

Embodiment 4 of the present invention further proposes a second base station, as shown in FIG. 5 , including:

The receiving module 501 is configured to receive the second reconstructed context information sent by the first base station.

The sending module 502 is configured to send, by the second base station, confirmation information to the first base station when it is determined according to the second re-establishment context information that the user equipment can re-establish a link through the second base station.

Embodiment 4 of the present invention further provides a user equipment, as shown in FIG. 6 , including:

Execute module 601, configured to re-establish a link through the first base station.

The sending module 602 is configured to send a re-establishment request when the user equipment is rejected by the first base station, where the re-establishment request includes second re-establishment context information.

Optionally, the above-mentioned execution module 601 is further configured to determine whether the link is re-established through the first base station for the first time; if the determination result is yes, determine the second reconstruction context information.

Embodiment 4 of the present invention further provides a link re-establishment apparatus, which is applied on the user equipment side, as shown in FIG. 7 , including:

A determination module 701, configured to determine whether it is the first time to re-establish a link through the first base station;

Executing module 702, configured to determine second re-establishment context information if the judgment result is yes; and send a second UE indication message to the first base station, wherein the second UE indication message includes the second re-establishment context information.

As will be appreciated by those skilled in the art, embodiments of the present invention may be provided as a method, an apparatus (apparatus), or a computer program product. Accordingly, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, magnetic disk storage, optical disk, optical storage, etc.) having computer-usable program code embodied therein.

The present invention is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (apparatus) and computer program products according to embodiments of the invention. It will be understood that each flow and/or block in the flowchart illustrations and/or block diagrams, and combinations of flows and/or blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to the processor of a general purpose computer, special purpose computer, embedded processor or other programmable data processing device to produce a machine such that the instructions executed by the processor of the computer or other programmable data processing device produce Means for implementing the functions specified in a flow or flow of a flowchart and/or a block or blocks of a block diagram.

These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory result in an article of manufacture comprising instruction means, the instructions The apparatus implements the functions specified in the flow or flow of the flowcharts and/or the block or blocks of the block diagrams.

These computer program instructions can also be loaded on a computer or other programmable data processing device to cause a series of operational steps to be performed on the computer or other programmable device to produce a computer-implemented process such that The instructions provide steps for implementing the functions specified in the flow or blocks of the flowcharts and/or the block or blocks of the block diagrams.

Although preferred embodiments of the present invention have been described, additional changes and modifications to these embodiments may occur to those skilled in the art once the basic inventive concepts are known. Therefore, the appended claims are intended to be construed to include the preferred embodiment and all changes and modifications that fall within the scope of the present invention.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention. Thus, provided that these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims (13)

1. A method for link re-establishment, comprising:

a first base station receives a reestablishment request sent by user equipment when reestablishment of a link through the first base station is rejected;

when the first base station determines that the reestablishment request contains second reestablishment context information, the first base station sends the second reestablishment context information to a second base station;

when the first base station receives confirmation information sent by a second base station, the first base station sends a first reestablishment rejection message to the user equipment, wherein the confirmation information is that the second base station determines that the user equipment can reestablish a link through the second base station according to the second reestablishment context information, and the first reestablishment rejection message contains the confirmation information.

2. The method of claim 1, further comprising:

and when the first base station determines that the reestablishment request does not contain second reestablishment context information, the first base station sends a second reestablishment rejection message to the user equipment, wherein the second reestablishment rejection message is used for informing that the user equipment is rejected to carry out link reestablishment.

3. The method of claim 1 or 2, wherein the first base station is a master base station, the second base station is a secondary base station, and the first base station governs the second base station.

4. The method of claim 1 or 2, wherein prior to the first base station receiving the reestablishment request sent by the user equipment upon the rejection of the link reestablishment by the first base station, further comprising:

the first base station judges whether the user equipment reestablishes a link through the first base station for the first time;

and if so, the first base station receives a reestablishment request sent when the user equipment reestablishes the link through the first base station and rejects.

5. A method for link re-establishment, comprising:

the second base station receives second reestablishment context information sent by the first base station, wherein the second reestablishment context information is contained in a reestablishment request sent when the user equipment is rejected by the first base station to reestablish a link;

and when the second base station determines that the user equipment can reestablish the link through the second base station according to the second reestablishment context information, the second base station sends confirmation information to the first base station, wherein the confirmation information comprises a first reestablishment rejection message sent to the user equipment when the first base station receives the confirmation information sent by the second base station.

6. A method for link re-establishment, comprising:

the user equipment reestablishes a link through the first base station;

when the user equipment determines that the link reestablishment through the first base station is rejected, sending a reestablishment request to the first base station, wherein the reestablishment request comprises second reestablishment context information;

the user equipment receives a first reestablishment rejection message sent by the first base station, and determines that a link can be reestablished through a second base station based on confirmation information included in the first reestablishment rejection message, wherein the confirmation information is sent to the first base station when the second base station determines that the user equipment can reestablish the link through the second base station according to the second reestablishment context information sent by the first base station.

7. The method of claim 6, wherein prior to sending a reestablishment request when the user equipment is rejected by the first base station, further comprising:

the user equipment determines whether a link is reestablished through the first base station for the first time;

and if so, the user equipment determines second reconstructed context information.

8. A first base station, comprising:

a receiving module, configured to receive a reestablishment request sent when the user equipment is rejected by reestablishing the link through the first base station;

a sending module, configured to send second reestablishment context information to a second base station when it is determined that the reestablishment request includes the second reestablishment context information; and when receiving confirmation information sent by a second base station, sending a first reestablishment rejection message to the user equipment, wherein the confirmation information is that the second base station determines that the user equipment can reestablish a link through the second base station according to the second reestablishment context information, and the first reestablishment rejection message includes the confirmation information.

9. The first base station of claim 8, wherein the sending module is further configured to send a second reconfiguration reject message to the ue when it is determined that the reconfiguration request does not include the second reconfiguration context information, where the second reconfiguration reject message is used to notify that the ue is rejected for link reconfiguration.

10. The first base station of claim 8 or 9, wherein the receiving module is further configured to determine whether the ue reestablishes a link through the first base station for the first time; and if so, receiving a reestablishment request sent by the user equipment when the link is reestablished and rejected through the first base station.

11. A second base station, comprising:

a receiving module, configured to receive second reestablishment context information sent by a first base station, where the second reestablishment context information is included in a reestablishment request sent when a user equipment is rejected to reestablish a link through the first base station;

a sending module, configured to send, by the second base station, acknowledgement information to the first base station when it is determined that the ue can reestablish the link through the second base station according to the second reestablishment context information, where the acknowledgement information includes a first reestablishment rejection message sent to the ue when the first base station receives the acknowledgement information sent by the second base station.

12. A user device, comprising:

an execution module, configured to reestablish a link through a first base station;

a sending module, configured to send a reestablishment request to the first base station when it is determined that the reestablishment of the link through the first base station is rejected, where the reestablishment request includes second reestablishment context information, receive a first reestablishment rejection message sent by the first base station, and determine, based on acknowledgement information included in the first reestablishment rejection message, that the link can be reestablished through a second base station, where the acknowledgement information is sent to the first base station by the second base station when it is determined that the user equipment can reestablish the link through the second base station according to the second reestablishment context information sent by the first base station.

13. The user equipment of claim 12, wherein the performing module is further configured to determine whether to re-establish a link with the first base station for the first time; and if so, determining second reconstructed context information.

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