WO2014044070A1

WO2014044070A1 - Connection reestablishment method and device

Info

Publication number: WO2014044070A1
Application number: PCT/CN2013/078401
Authority: WO
Inventors: 梁靖
Original assignee: 电信科学技术研究院
Priority date: 2012-09-20
Filing date: 2013-06-28
Publication date: 2014-03-27
Also published as: CN103687053A

Abstract

The application discloses a connection reestablishment method and device, so as to increase the success rate of user equipment (UE) reestablishment in a heterogeneous network scenario, thereby improving network robustness. The method comprises: another base station, other than a local station currently providing a service for a UE, receiving reestablishment context information of the UE sent by the local base station currently providing the service for the UE; if the UE undergoes a radio link failure, the another base station reestablishing a radio link for the UE according to the reestablishment context information.

Description

Method and device for connection reconstruction

The present application claims priority to Chinese Patent Application No. 201210352723.9, entitled "A Method and Apparatus for Connection Reconstruction", filed on September 20, 2012, the entire contents of in.

Technical field

The present invention relates to the field of communications technologies, and in particular, to a method and device for connection reestablishment. Background technique

Statistics show that the traditional Macro eNB (macro base station) single-layer overlay network can not meet the growing demand for data service rate and data capacity. Therefore, 3GPP (3rd Generation Partnership Project) introduced a layered networking solution to solve this problem: deploying low-power in small coverage environments such as hotspots, home indoor environments, and office environments. Local eNB (local base station), which obtains the effect of cell splitting, enables operators to provide users with higher data rates and lower cost services. The local base station can include Femto (femtocell), Pico (picocell), and Relay. (relay) and other forms.

In the hierarchical network in the existing hierarchical networking mode as shown in FIG. 1, the macro base station (or Macro cell) provides basic coverage, and the local base station (or Local cell) provides hotspots. Coverage, there is a data/signaling interface (wired/wireless interface) between the local base station (or local cell) and the macro base station (or macro cell), and the UE can work in the macro base station (or macro cell) or the local base station (or local cell) ) Next. The network architecture of the layered network is the same as that of the Long Term Evolution (LTE) system. The MME (Mobility Management Entity) or the S-GW (Serving GW) serves to simultaneously connect the macro base station and the local base station.

The coverage of the cell controlled by the Local eNB is small, and the UE (user equipment) connected to the Local eNB can often obtain a better service shield, such as: obtaining a higher service rate and a higher shield link. Therefore, when the UE connected to the Macro eNB approaches the cell controlled by the Local eNB, it can switch to the Local eNB to obtain the service provided by the Local eNB; when the UE is away from the cell controlled by the Local eNB, it needs to switch to the cell controlled by the Macro eNB to Stay connected wirelessly. Due to the large number of local eNBs and small coverage, the UE needs to frequently switch between the cell controlled by the Macro eNB and the cell controlled by the Local eNB.

In the LTE system, when the UE fails to perform handover, RLF (Radio Link Failure), RRC (Radio Resource Control) connection reconfiguration failure, or integrity check failure, the UE is triggered to perform RRC. The connection reconstruction process is designed to restore SRB1 (Signaling Radio Bearer 1) and restore security. The reconstruction process, as shown in Figure 2, mainly includes the following steps:

Step 201: The UE suspends all but the Signaling Radio Bearer 0 (SRB0) RB (Radio bearer, radio bearer);

Step 202: The UE resets the MAC (Medium Access Control) layer, and performs a cell selection process by using a default configuration, where the default configuration includes a default physical layer configuration, a MAC layer configuration, and an SPS (Semi-Persistent Scheduling, Semi-persistent scheduling) configuration;

Step 203: When the UE selects a suitable cell, the cell sends an RRC connection reestablishment request message to the base station, where the message includes the identifier information of the UE.

Step 204: The base station receives the RRC connection reestablishment request message of the UE, and if the UE is allowed to reestablish (the base station side stores the context information of the UE), the RRC connection reestablishment message is sent to the UE, where the radio resource configuration information is written in the reestablishment message. ;

Step 205: The UE recovers the SRB1 after receiving the RRC connection reestablishment message, and updates the key according to the security information in the reestablishment message, and the SRB2 (Signaling Radio Bearer 2) and all the DRBs (Dedicated Radio Bearer) The radio bearer is still suspended. If the reconfiguration message includes radio resource configuration information (physical layer configuration, MAC layer configuration, SPS configuration, SRB1 configuration, etc.), the UE follows the radio resource configuration information to the bottom layer (PDCP (Packet Data). Convergence Protocol (Packet Data Convergence Protocol), RLC (Radio Link Control), MAC and physical layer are configured. After the configuration is complete, the UE sends an RRC connection reestablishment completion message to the base station.

Step 206: The eNB receives the RRC connection reestablishment complete message, and the RRC connection reestablishment process is completed. To recover the SRB2 and the DRB, after receiving the reestablishment complete message, the base station sends an RRC connection reconfiguration message to the UE to restore the SRB2 and the DRB.

Step 207: If the RRC connection reconfiguration message received by the UE is the first reconfiguration message after the reestablishment process, the information is restored.

The SRB2 and all the DRBs perform the underlying configuration according to the content of the reconfiguration message, the reconfiguration is completed, and the SRB2 and the DRB are restored. Then, the UE returns an RRC connection reconfiguration complete message to the base station.

In the case of hierarchical networking, there are many base stations with different coverage and types in the network, forming a heterogeneous network. The cells under the Local eNB in the heterogeneous network can use backward compatible cells, which can be A new type of cell. If it is a backward compatible cell, the UE may camp on or access from the cell. If it is a new type of cell, the cell may not be able to provide the camping of the idle state UE, and the idle state UE cannot access the cell, but the cell may provide data transmission for the UE in the connected state, and the UE in the connected state may Other cells can be switched to the cell and can also be cut out.

If the UE fails to generate a radio link in the backward compatible cell, if the UE does not search for the previous serving cell, the UE will initiate re-establishment in other cells. If the UE fails to establish a radio connection in the new type of cell, the UE Cell search can only be performed again, and connection re-establishment is initiated in other cells. Since the cell coverage under the Local eNB is small, the UE is likely to be reestablished in other cells. Since other cells do not have context information of the UE, This will cause the UE's reconstruction to fail.

The invention provides a connection reconstruction method and device, which are used to improve the success rate of UE reconstruction in a heterogeneous network scenario and improve the robustness of the network.

The specific technical solutions provided by the implementation of the present invention are as follows:

A method of connection reconstruction, including:

The base station other than the local base station currently serving the user equipment UE receives the reconstruction context information of the UE that is currently sent by the local base station that provides the service to the UE;

And if the UE fails to generate a radio link, the other base station re-establishes a radio link for the UE according to the re-establishment context information.

A network side device, including:

a receiving unit, configured to receive re-establishment context information of the UE that is currently sent by the local base station serving the user equipment UE;

And a reconstruction unit, configured to re-establish a wireless link for the UE according to the reconstruction context information when the UE fails to generate a radio link.

Based on the foregoing technical solution, in the embodiment of the present invention, other base stations other than the local base station currently serving the UE can obtain the radio link of the UE by receiving the reconstruction context information of the UE that is currently sent by the local base station serving the UE. Upon failure, the other base station reconstructs the radio link for the UE according to the received re-establishment context information of the UE, thereby avoiding the cell re-establishment of the other base stations when the radio link fails in the existing heterogeneous network. The problem that the reestablishment fails in the heterogeneous network scenario can improve the success rate of the UE in the heterogeneous network scenario, improve the robustness of the network, and improve the user experience. DRAWINGS

1 is a schematic diagram of a layered network architecture in the background art;

2 is a schematic diagram of an RRC connection reestablishment process of an LTE system in the background art;

3 is a flowchart of a method for performing connection reestablishment according to an embodiment of the present invention;

4 is a schematic diagram of a network scenario according to a specific embodiment of the present invention;

FIG. 5 is a schematic structural diagram of a network side device according to an embodiment of the present invention;

FIG. 6 is a schematic structural diagram of another network side device according to an embodiment of the present invention. detailed description

In the existing heterogeneous network, when the UE has a radio link failure and needs to be reestablished in the cell of another base station, the re-establishment failure occurs because the cell under the other base station does not have the re-establishment context information of the UE. A method and apparatus for connection reconstruction is provided.

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

As shown in FIG. 3, in the embodiment of the present invention, the detailed method for performing connection reconstruction is as follows:

Step 301: The other base station except the local base station currently serving the UE receives the reconstruction context information of the UE sent by the local base station that is currently serving the UE.

Specifically, the re-establishment context information includes, but is not limited to: a PCI (Physical Cell ID) of the serving cell served by the UE under the local base station, and a C-RNTK Cell Radio Network Temporary Identifier, receiving Cell ID (cell identity), security parameter and security key of the target reestablished cell under other base stations for reconstructing context information, UE security capability, security related parameter NCC (NextHop Chaining Count, next hop count value), and wireless capability.

Preferably, after the other base station receives the reconstruction context information of the UE sent by the local base station, the reconstruction context information is saved.

In the embodiment of the present invention, the other base stations distinguish the reconstruction context information of different UEs according to the UE reconstruction context identifier, where the UE reconstruction context identifier is a predefined identifier (ie, a newly defined identifier) or is a reconstruction identifier of the UE (ie, re-use of the UE). An identifier, where the re-establishment identifier of the UE is composed of a PCI of the serving cell, a C-RNTI used in the serving cell, and a Short Message Authentication Code for Integrity (Short Message Authentication Code) for integrity protection. String.

Preferably, the other base station that receives the reconstruction context information of the UE may be: another local base station or macro base station within the local base station setting range that transmits the reconstruction context information of the UE.

Step 302: If the radio link fails, the other base station that receives the reconfiguration context information of the UE reestablishes the radio link for the UE according to the reestablishment context information.

In a first implementation, after the other base stations other than the local base station currently serving the UE receive the reconstruction context information of the UE sent by the local base station, it is determined that the UE fails to generate a radio link.

In this specific implementation, after the other base station receives the reestablishment context information of the UE sent by the local base station, it is determined that before the radio link failure occurs, if the reconfiguration context information of the UE is updated, the other base station receives the bearer update sent by the local base station. The reconstruction context information update request of the reconstruction context information, and the other base station updates the locally saved reconstruction context information of the UE with the updated reconstruction context information.

In this implementation, preferably, if the other base station that receives the reconstruction context information is a macro base station, the macro base station receives the local base station. After the reestablishment context information of the UE sent by the base station, it is determined that before the radio link failure of the UE occurs, if the UE switches from the local base station to another local base station, the macro base station receives the retransmission of the new reestablishment context information sent by the other local base station. The context update message is used by the macro base station to update the locally saved reconstruction context information of the UE by using the new reestablishment context information carried in the reestablishment context update message.

In this implementation, after the other base station receives the reestablishment context information of the UE sent by the local base station, before determining that the radio link fails, the local base station sends a dedicated signaling carrying the re-established cell preference list to the UE, and the re-establishment Each cell included in the cell preference list is a cell under other base stations that have obtained reconstruction context information. Preferably, after the UE fails the radio link, the UE selects the cell in the rebuilt cell preference list to reestablish the radio link.

In a second implementation, before the base station other than the local base station currently serving the UE receives the reestablishment context information of the UE sent by the local base station, determining that the radio link fails, the other base station requests the UE from the local base station. Rebuild context information.

In this implementation, after the UE fails the radio link, the UE initiates an RRC connection reestablishment process at the other base station, and the other base station requests the local base station to reestablish the context information of the UE.

The method of connection reconstruction provided by the present invention will be described in detail below through three specific embodiments.

In the first embodiment, the UE is provided with a serving local base station to send the UE's reestablishment context information to other neighboring base stations before the radio link fails. The details are as follows:

As shown in FIG. 4, in the network scenario, the UE works in the cell under Local e Bl, and Local e Bl sends the re-establishment context information of the UE to the Macro e B. The re-establishment context information includes: Local eNB1 under the UE current PCI of the serving cell, C-RNTI used in the current serving cell of the UE, Cell ID of the target reestablished cell under the Macro eNB, security parameter ShortMAC-I, security key (ie, eNB side key (Ke B*)), UE Security capability, security related parameters NCC, and wireless capabilities of the UE.

The reconstruction context information of the UE is identified by using the "UE Reestablishment Context Identifier" so that the base station can distinguish the reconstruction context information of different UEs. The UE reconstruction context identifier may be a newly defined identifier, or may be a re-establishment identifier of the reused UE (ie, a PCI of the serving cell, a character string composed of C-RNTI and ShortMAC-I used in the serving cell).

The Macro eNB saves after receiving the reconstruction context information. If the UE re-establishes the context information of the UE during the operation of the Local eNB1, the Local eNB1 sends a re-establishment context information update request to the Macro eNB, and sends the new re-establishment context information to the Macro eNB, and the Macro eNB receives the request. The saved reconstruction context information of the UE is updated.

If the UE subsequently operates in the cell under Local eNB1, the radio link fails, and after the UE performs cell selection again, the cell under the Macro eNB is selected to initiate an RRC connection reestablishment process, because the cell under the Macro eNB The reconstruction context information of the UE has been saved, and the UE is successfully re-established, and the service can continue to be accepted under the Macro eNB.

If the UE subsequently operates in the cell under the Local eNB1, no abnormality occurs, and the UE switches from Local e Bl to Local e B2 due to the mobility. After the UE successfully completes the handover procedure, the Local e B2 sends a Reconstruction Context Update message to the Macro eNB. The Reconstruction Context Update message carries the new reestablishment context information, and the Macro eNB updates the locally saved reestablishment context information. Alternatively, after the UE successfully completes the handover procedure, the Local eNB1 notifies the Macro eNB to delete the saved reestablishment context information of the UE, and subsequently Local e B2 sends the reconstruction context information of the UE to the Macro eNB.

If the UE subsequently operates in the cell under the Local eNB1, no abnormality occurs, and the UE switches from the Local eNB 1 to another Macro e B2 that does not store the reconstruction context information of the UE due to the mobility, after the UE successfully completes the handover process. The Local eNB 1 notifies the Macro eNB to delete the reconstructed context information of the saved UE.

In a second specific embodiment, after the UE fails to generate a radio link, the base station that performs connection reestablishment for the UE provides the UE with the reconfiguration context information of the UE.

The network scenario is the same as that shown in FIG. 4, the UE works in the cell under the Local eNB1, the radio link fails during the working process, the UE re-selects the cell, and selects the cell under the Macro eNB to initiate an RRC connection reestablishment request message. The Macro eNB determines the Local eNB 1 according to the source ' and the area identifier carried in the RRC Connection Reestablishment Request message, and requests the Local eNB 1 to re-establish the context information of the UE. After receiving the request, the Local eNB1 sends the re-establishment context information of the UE. After receiving the reconstruction context information, the Macro eNB allows the UE to successfully complete the RRC connection reestablishment process in the cell under it.

The third embodiment is further optimized for the first embodiment. After the Local eNB1 sends the re-establishment context information of the UE to the Macro eNB, the Local eNB1 notifies the UE to re-establish the cell preference list by using dedicated signaling. Each of the included cells is a cell that can be used for reconstruction of the UE under the Macro eNB, and the UE saves after receiving the rebuilt cell preference list.

If the radio link fails in the cell operation of the local eNB1, the UE selects the cell in the locally saved re-established cell preference list and the source serving cell of the UE (that is, the current wireless connection occurs). If the cell included in the re-established cell list is successfully selected, the UE initiates an RRC connection re-establishment procedure in the selected cell, if the cell in the re-established cell preference list is not suitable for the UE to camp on, The UE then selects another cell to initiate a reconstruction process.

Based on the same inventive concept, a network side device is further provided in the embodiment of the present invention. For the specific implementation of the network side device, refer to the description of the foregoing method, and the repeated description is not repeated, as shown in FIG. 5, the network side The equipment mainly includes the following units: The receiving unit 501 is configured to receive the re-establishment context information of the UE that is currently sent by the local eNodeB serving the UE. The re-establishing unit 502 is configured to re-establish the radio chain for the UE according to the re-establishment context information when the radio link fails. road.

The receiving unit 501 is further configured to: after receiving the re-establishment context information of the UE sent by the local base station, save the re-establishment context information; the re-establishment context information includes a PCI and a C-RNTI of the serving cell of the UE under the local base station, where the network side The cell identity, security parameters, and security key of the target reestablished cell under the device, the security capability of the UE, the next hop count value, and the wireless capability.

The receiving unit 501 is further configured to: re-establish the re-establishment context information of the UE according to the UE re-establishment context identifier, where the UE re-establishment context identifier is a predefined identifier or a re-establishment identifier of the UE, where the re-establishment identifier of the UE is a PCI of the serving cell A string consisting of C-RNTI and ShortMAC-I used in the serving cell.

In a specific implementation, the receiving unit 501 is further configured to: after receiving the reconstruction context information of the UE sent by the local base station, determine that the UE fails to generate a radio link.

The specific implementation further includes an updating unit 503, configured to: after receiving the reestablishment context information of the UE sent by the local base station, the receiving unit 501 determines that the reconfiguration context information of the UE is updated before receiving the radio link failure of the UE, and receiving the The reconstruction context information update request sent by the local base station carrying the updated reconstruction context information, and updating the locally saved reconstruction context information by using the updated reconstruction context information.

If the network side device is a macro base station in the specific implementation, the receiving unit 501 is further configured to: after receiving the reconfiguration context information of the UE sent by the local base station, determine, before the UE fails to generate a radio link, if the UE switches from the local base station to another A local base station receives the reestablishment context update message sent by the other local base station and carries the new reestablishment context information, and updates the locally saved reconstruction context information by using the new reestablishment context information carried in the reestablishment context update message.

In another implementation, the receiving unit 501 is further configured to: before receiving the reconfiguration context information of the UE sent by the local base station, determine that the UE fails to generate a radio link, and request the reestablishment context information of the UE from the local base station.

Based on the same inventive concept, another network side device is further provided in the embodiment of the present invention. For the specific implementation of the network side device, refer to the description of the foregoing method, and the repeated description is omitted, as shown in FIG. The side equipment mainly includes the following units:

The receiver 601 is configured to receive re-establishment context information of the UE that is currently sent by the local base station serving the UE. The processor 602 is configured to re-establish the radio chain for the UE according to the re-establishment context information when the radio link fails. road. The receiver 601 is further configured to: after receiving the reconstruction context information of the UE sent by the local base station, save the reconstruction context information; the reconstruction context information includes a PCI and a C-RNTI of the UE serving cell under the local base station, where the network side The cell identity, security parameters, and security key of the target reestablished cell under the device, the security capability of the UE, the next hop count value, and the wireless capability.

The receiver 601 is further configured to: re-establish the re-establishment context information of the UE according to the UE re-establishment context identifier, where the UE re-establishment context identifier is a predefined identifier or a re-establishment identifier of the UE, where the re-establishment identifier of the UE is a monthly service cell PCI, a string consisting of C-RNTI and ShortMAC-I used in the serving cell.

In a specific implementation, the receiver 601 is further configured to: after receiving the reconstruction context information of the UE sent by the local base station, determine that the UE fails to generate a radio link.

In the specific implementation, the processor 602 is further configured to: after the receiver 601 receives the reestablishment context information of the UE sent by the local base station, before determining that the radio link failure occurs in the UE, if the reconfiguration context information of the UE is updated, the local The reconstruction context information update request sent by the base station carrying the updated reconstruction context information, and updating the locally saved reconstruction context information by using the updated reconstruction context information.

If the network side device is a macro base station, the receiver 601 is further configured to: after receiving the reconfiguration context information of the UE sent by the local base station, determine that the UE switches from the local base station to another before the radio link failure occurs in the UE. A local base station receives the reestablishment context update message sent by the other local base station and carries the new reestablishment context information, and updates the locally saved reconstruction context information by using the new reestablishment context information carried in the reestablishment context update message.

In another implementation, the receiver 601 is further configured to: before receiving the reconfiguration context information of the UE sent by the local base station, determine that the UE fails to generate a radio link, and request the reestablishment context information of the UE from the local base station.

Those skilled in the art will appreciate that embodiments of the present invention can be provided as a method, system, or computer program product. Accordingly, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment, or a combination of software and hardware. Moreover, the present invention can be embodied in the form of a computer program product embodied on one or more computer-usable storage interfaces (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer usable program code.

The present invention has been described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (system), and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flowchart illustrations and/or FIG. These computer program instructions can be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing device to produce a machine for the execution of instructions for execution by a processor of a computer or other programmable data processing device. To implement the functions specified in one or more blocks of a flow or a flow and/or block diagram of a flowchart Device.

The computer program instructions can also be stored in a computer readable memory that can direct a computer or other programmable data processing device to operate in a particular manner, such that the instructions stored in the computer readable memory produce an article of manufacture comprising the instruction device. The apparatus implements the functions specified in one or more blocks of a flow or a flow and/or block diagram of the flowchart.

These computer program instructions can also be loaded onto a computer or other programmable data processing device such that a series of operational steps are performed on a computer or other programmable device to produce computer-implemented processing for execution on a computer or other programmable device. The instructions provide steps for implementing the functions specified in one or more of the flow or in a block or blocks of a flow diagram.

Although the preferred embodiment of the invention has been described, it will be apparent to those of ordinary skill in the art that <RTIgt; Therefore, the appended claims are intended to be construed as including the preferred embodiments and the modifications

It is apparent that those skilled in the art can make various modifications and variations to the invention without departing from the spirit and scope of the invention. Thus, it is intended that the present invention cover the modifications and modifications of the invention

Claims

Rights request

1. A method of connection reconstruction, characterized by including:

Base stations other than the local base station currently providing services to the user equipment UE receive the reconstruction context information of the UE sent by the local base station currently providing services to the UE;

If a wireless link failure occurs in the UE, the other base stations reestablish a wireless link for the UE based on the reestablishment context information.

2. The method of claim 1, wherein the reconstruction context information includes the physical layer cell identity PCI and the cell radio network temporary identity C-RNTI of the serving cell serving the UE under the local base station. The cell identity, security parameters and security keys of the target reconstructed cells under other base stations, the security capabilities, next hop count value and wireless capabilities of the UE;

After the other base station receives the reconstruction context information of the UE sent by the local base station, the method further includes: the other base station saves the reconstruction context information.

3. The method according to claim 2, characterized in that, after the other base station receives the reestablishment context information of the UE sent by the local base station, the method includes: determining that the UE has a wireless link failure.

4. The method according to claim 2, characterized in that, before the other base station receives the reconstruction context information of the UE sent by the local base station, it includes:

It is determined that the UE has a wireless link failure, and the other base station requests the local base station for reestablishment context information of the UE.

5. The method of claim 3, wherein after the other base station receives the reestablishment context information of the UE sent by the local base station and before determining that the UE has a wireless link failure, it further includes:

If the re-establishment context information of the UE is updated, the other base stations receive the re-establishment context information update request carrying the updated re-establishment context information sent by the local base station, and the other base stations use the updated re-establishment context information to update The locally saved reconstruction context information.

6. The method of claim 3, wherein the other base stations are macro base stations;

After the other base station receives the reestablishment context information of the UE sent by the local base station and before determining that the UE has a wireless link failure, it also includes:

If the UE is handed over from the local base station to another local base station, the macro base station receives a re-establishment context update message carrying new re-establishment context information sent by the other local base station;

The macro base station uses the new reconstruction context information carried in the reconstruction context update message to update the locally stored reconstruction context information.

7. The method of claim 4, wherein after the UE fails to perform a radio link, the UE Before the other base station requests the reestablishment context information of the UE from the local base station, it also includes:

The UE initiates an RRC connection reestablishment process at the other base station.

8. The method of claim 3, wherein after the other base station receives the reestablishment context information of the UE sent by the local base station and before determining that the UE has a wireless link failure, it further includes:

The local base station sends dedicated signaling carrying a preferred list of reestablished cells to the UE, and each cell included in the preferred list of reestablished cells is a cell under the other base station that has obtained the reestablished context information.

9. The method of claim 8, wherein after the UE occurs a radio link failure, the method includes: the UE selecting a cell in the reestablishment cell preference list to reestablish the radio link.

10. The method according to any one of claims 1 to 9, further comprising:

The other base stations distinguish the reconstruction context information of different UEs according to the UE reconstruction context identification. The UE reconstruction context identification is a predefined identification or the reconstruction identification of the UE. The reconstruction identification of the UE is composed of the PCI of the serving cell and the serving cell. A string consisting of the C-RNTI used in the message and the short message authentication code ShortMAC-I used for integrity protection.

11. A network side device, characterized by including:

A receiving unit, configured to receive the reconstructed context information of the UE sent by the local base station currently serving the user equipment UE;

A re-establishment unit, configured to re-establish a wireless link for the UE based on the re-establishment context information when a wireless link failure occurs in the UE.

12. The network side device according to claim 11, wherein the receiving unit is further configured to: after receiving the reconstruction context information of the UE sent by the local base station, save the reconstruction context information;

The reconstruction context information includes the PCI and C-RNTI of the UE serving cell under the local base station, the cell identity, security parameters and security keys of the target reconstruction cell under the network side device, the security capabilities of the UE, Next hop count value and wireless capabilities.

13. The network side device according to claim 12, wherein the receiving unit is further configured to: determine that a wireless link failure has occurred in the UE after receiving the reestablishment context information of the UE sent by the local base station. .

14. The network side device according to claim 12, wherein the receiving unit is further configured to: determine that a wireless link failure occurs in the UE before receiving the reestablishment context information of the UE sent by the local base station. , requesting the local base station for the reconstruction context information of the UE.

15. The network side device according to claim 13, further comprising:

The update unit is configured to receive, at the receiving unit, the reconstruction context information of the UE sent by the local base station. Afterwards, before it is determined that the UE has a wireless link failure, if the re-establishment context information of the UE is updated, receive a re-establishment context information update request carrying the updated re-establishment context information sent by the local base station, and use all the updated re-establishment context information. The reconstructed context information updates the locally saved reconstructed context information.

16. The network side device according to claim 13, wherein the network side device is a macro base station; the receiving unit is further configured to: after receiving the reconstruction context information of the UE sent by the local base station, Before determining that a wireless link failure occurs in the UE, if the UE switches from the local base station to another local base station, receive a re-establishment context update message carrying new re-establishment context information sent by the other local base station, and use The new reconstruction context information carried in the reconstruction context update message updates the locally saved reconstruction context information.

17. The network side device according to any one of claims 11 to 16, wherein the receiving unit is further configured to: distinguish the reconstruction context information of different UEs according to the UE reconstruction context identifier, and the UE reconstruction context identifier is The predefined identifier may be a reestablishment identifier of the UE, which is a string composed of the PCI of the serving cell, the C-RNTI and ShortMAC-I used in the serving cell.