CN106604337A - RRC connection rebuilding method and system - Google Patents

Abstract

The invention discloses an RRC connection re-establishment method and system, relates to the technical field of wireless communication, and is used for solving the problem of low success rate of RRC connection re-establishment after S1 handover failure. The method includes: the MME generates a handover request message according to the handover request message sent by the source base station through the S1 interface and sends it to the target base station through the S1 interface; after the S1 handover fails, when the handover request message and the RRC connection re-establishment request sent by the UE When the message matches successfully, the target base station retrieves the context information of the UE in the source cell in the handover request message, and completes the RRC connection re-establishment process of the UE in the target cell according to the context information. The handover request message, handover request message and Each RRC connection re-establishment request message includes the PCI of the source cell and the C-RNTI used by the UE in the source cell. The invention is applied in LTE wireless network.

Description

A method and system for re-establishing an RRC connection

technical field

The present invention relates to the technical field of wireless communication, in particular to a method and system for re-establishing an RRC connection.

Background technique

A cell in a wireless communication system, such as a Long Term Evolution (LTE) cell, has a certain coverage. When a user equipment (User Equipment, UE) in the connected state enters another LTE cell from one LTE cell, the UE needs to be handed over from the LTE cell it left to the LTE cell the UE entered in order to maintain the continuity of communication, the above The process is called cell handover. Wherein, the LTE cell that the UE leaves is called a source cell (Source Cell), and the cell that the UE enters is called a target cell (Object Cell). If the source cell and the target cell are controlled by different base stations (eNB), the above-mentioned cell handover process is a cross-base station handover, wherein the base station controlling the source cell is the source base station (Source eNB), and the base station controlling the target cell is the target base station (Obeject eNB). ).

According to the LTE protocol, as shown in Figure 1, the LTE wireless network system includes a UE, a Mobility Management Entity (MME), a source base station, and a target base station. The connection between the source base station and the target base station is through the X2 port, and the connection between the UE and the source base station or between the UE and the target base station is through the Uu port. When there are X2 ports between base stations, inter-base station handover is generally performed through the X2 port, so as to save S1 port resources and improve the efficiency of the LTE wireless network. However, when there is no X2 interface between the source base station and the target base station, or when the X2 interface fails, the inter-base station handover can only be performed through the S1 interface, and the inter-base station handover at this time is called S1 handover.

In practical applications, S1 handover may fail due to many reasons, for example, the target cell does not have enough radio resources to bear the services of the UE before the handover. When the S1 handover fails, the UE will first initiate a radio resource control (Radio Resource Control, RRC) connection re-establishment process, trying to restore the RRC connection between the UE and the LTE wireless network. When the source cell receives the RRCConnectionReestablishmentRequest message (RRCConnectionReestablishmentRequest), since the source base station saves the identity information and context information of the UE in the source cell in the local resource, the source base station can easily identify the UE and find the UE in the The context information of the source cell, and then the RRC connection between the UE and the LTE wireless network is reestablished in the source cell.

However, when the target cell receives the RRC connection re-establishment request message, since the target base station does not store the identity information of the UE in the source cell in the local resources of the target base station, the target base station cannot identify the UE, nor can it obtain the context information of the UE in the source cell. Therefore, the target cell will reject the RRC connection re-establishment request of the UE, resulting in RRC connection re-establishment failure.

From the above, there is a problem in the prior art that the success rate of RRC connection re-establishment is low after the S1 handover fails.

Contents of the invention

The present invention provides an RRC connection re-establishment method and system, which are used to solve the problem of low success rate of RRC connection re-establishment after S1 handover failure.

To achieve the above object, the present invention adopts the following technical solutions:

In a first aspect, the present invention provides a method for re-establishing an RRC connection, including:

The MME receives and saves the handover request message (HandOver Required) sent by the source base station through the S1 interface. The handover request message includes the physical cell identifier (Physical Cell Identifier, PCI) of the source cell and the cell used by the UE in the source cell Cell Radio Network Temporary Identify (C-RNTI);

The MME generates a HandOver Request message (HandOver Request) according to the HandOver Request message, and sends it to the target base station through the S1 interface, and the HandOver Request message includes the PCI of the source cell and the C-RNTI used by the UE in the source cell;

The target base station receives and saves the hand-in request message;

After the S1 handover fails, the UE sends an RRC connection re-establishment request message to the target base station, and the RRC connection re-establishment request message includes the PCI of the source cell and the C-RNTI used by the UE in the source cell;

When the handover request message and the RRC connection re-establishment request message match successfully, the target base station retrieves the context information of the UE in the source cell from the handover request message, and completes the RRC of the UE in the target cell according to the context information Connection re-establishment process.

In the first possible implementation manner of the first aspect, the handover request message and the RRC connection re-establishment request message match successfully, including:

The PCI of the source cell in the handover request message is equal to the PCI of the source cell in the RRC connection re-establishment request message, and the C-RNTI used by the UE in the source cell in the handover request message is the same as the RRC The C-RNTI used by the UE in the source cell in the connection re-establishment request message is equal.

With reference to the first aspect or the first possible implementation of the first aspect, in the second possible implementation, before the source base station sends the handover request message to the MME through the S1 interface, the method further includes:

The UE sends a measurement report of the target cell to the source base station, where the measurement report includes the PCI, RSRP and RSRQ of the target cell;

The source base station receives and saves the measurement report, and then judges according to the measurement report whether the target cell is a neighbor cell of the source cell and whether the target cell satisfies the handover condition, wherein

When the PCI of the target cell is equal to the PCI of a neighboring cell in the neighboring cell configuration of the source cell, the target cell is a neighboring cell of the source cell; when the RSRP of the target cell is higher than the RSRP of the source cell and the duration exceeds the first threshold and /or when the RSRQ of the target cell is higher than the RSRQ of the source cell and the duration exceeds the second threshold, the target cell meets the handover condition.

Compared with the prior art, the RRC connection re-establishment method provided by the first aspect of the present invention has the following beneficial effects:

In the prior art, after the S1 handover fails, since the identity of the UE cannot be identified, and the context information of the UE in the source cell in the handover request message cannot be obtained according to the identity of the UE, the target cell will reject the RRC connection re-establishment request of the UE, resulting in X2 After the handover fails, the success rate of RRC connection re-establishment is low.

However, in the RRC connection re-establishment method provided by the present invention, the switch-out request message, the switch-in request message and the RRC connection re-establishment request message all include the PCI of the source cell and the C-RNTI used by the UE in the source cell. After the S1 handover fails, when the PCI of the source cell in the handover request message is equal to the PCI of the source cell in the RRC connection re-establishment request message, and the C-RNTI used by the UE in the source cell in the handover request message is the same as When the C-RNTI used by the UE in the source cell in the RRC connection re-establishment request message is equal, the target base station determines that the source cell in the RRC connection re-establishment request message is the same cell as the source cell in the hand-in request message , and the UE in the RRC connection re-establishment request message and the UE in the handover request message are the same UE, which is equivalent to successfully identifying the identity of the UE; then the target base station uses the context information of the UE in the source cell in the handover request message for During the RRC connection re-establishment of the UE in the target cell, the target base station can more accurately schedule appropriate resources for the UE, thereby improving the success rate of the RRC connection re-establishment of the UE in the target cell.

Moreover, compared with the prior art, the RRC connection re-establishment method provided by the present invention only includes the PCI of the source cell and the C-RNTI used by the UE in the source cell in the handover request message and the handover request message, without adding S1 In addition, due to the increased success rate of RRC connection re-establishment, there is no need for the UE to re-search the network and try to access the wireless network after the RRC connection re-establishment fails, which improves the efficiency of the LTE wireless network.

In addition, the method for re-establishing the RRC connection after the S1 handover failure provided by the present invention can be realized only by upgrading the software, without adding hardware, and the upgrading operation is convenient.

In a second aspect, the present invention provides an RRC connection re-establishment system, the system comprising:

The source base station is configured to send a handover request message to the MME through the S1 interface, where the handover request message includes the PCI of the source cell and the C-RNTI used by the UE in the source cell;

MME, configured to receive and store the handover request message;

The MME is further configured to generate a handover request message according to the handover request message, and send it to the target base station through the S1 interface, where the handover request message includes the PCI of the source cell and the C-RNTI used by the UE in the source cell;

The UE is configured to send an RRC connection re-establishment request message to the target base station after the S1 handover fails, and the RRC connection re-establishment request message includes the PCI of the source cell and the C-RNTI used by the UE in the source cell; and

a target base station, configured to receive and store the hand-in request message;

The target base station is further configured to receive and store the RRC connection re-establishment request message after the S1 handover fails;

The target base station is further configured to retrieve context information of the UE in the source cell in the handover request message when the handover request message and the RRC connection re-establishment request message match successfully, and complete the process according to the context information The RRC connection re-establishment process of the UE in the target cell.

In a first possible implementation manner of the second aspect, the matching of the handover request message and the RRC connection re-establishment request message successfully includes:

The PCI of the source cell in the handover request message is equal to the PCI of the source cell in the RRC connection re-establishment request message, and the C-RNTI used by the UE in the source cell in the handover request message is the same as the RRC The C-RNTI used by the UE in the source cell in the connection re-establishment request message is equal.

In combination with the second aspect or the first possible implementation of the second aspect, in the second possible implementation of the second aspect,

The UE is further configured to send a measurement report of the target cell to the source base station, where the measurement report includes the PCI, RSRP and RSRQ of the target cell; and

The source base station is further configured to receive and save the measurement report before sending a handover request message to the MME through the S1 interface, and then judge whether the target cell is a neighboring cell of the source cell and whether the target cell satisfies the following requirements according to the measurement report. switching conditions, where

When the PCI of the target cell is equal to the PCI of a neighboring cell in the neighboring cell configuration of the source cell, the target cell is a neighboring cell of the source cell; when the RSRP of the target cell is higher than the RSRP of the source cell and the duration exceeds the first threshold and /or when the RSRQ of the target cell is higher than the RSRQ of the source cell and the duration exceeds the second threshold, the target cell meets the handover condition.

The RRC connection re-establishment system provided by the second aspect of the present invention has the same advantages as the RRC connection re-establishment method described in the first aspect over the prior art, and details are not repeated here.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. Those skilled in the art can also obtain other drawings based on these drawings without creative work.

FIG. 1 is a schematic diagram of a cross-base station handover scenario provided by the background technology of the present invention;

FIG. 2 is a flow chart of the RRC connection re-establishment method provided by Embodiment 1 of the present invention;

FIG. 3 is a structural diagram of an RRC connection re-establishment system provided by Embodiment 2 of the present invention.

detailed description

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention.

Embodiment one

As shown in Figure 2, Embodiment 1 of the present invention provides a method for re-establishing an RRC connection, the method comprising:

Step 201, MME receives and saves the handover request message sent by the source base station through the S1 interface, the handover request message includes the PCI of the source cell and the C-RNTI used by the UE in the source cell.

Among them, the handover request message refers to the handover request signaling reported by the source base station to the MME when the UE leaves the source cell and enters the target cell and needs to perform a handover process across base stations, and the X2 interface does not exist or the X2 interface is unavailable due to a fault, including The context information of the source cell, such as the maximum data rate, MME identity, and UE capability, is used to forward to the target base station through the MME, and re-establish the RRC connection between the UE and the LTE wireless network in the target cell to restore communication services.

Moreover, in addition to the above context information, the handover request message also includes the PCI of the source cell and the C-RNTI used by the UE in the source cell. The PCI is the physical layer cell identity of the LTE cell, including a physical layer cell identification group number corresponding to the secondary synchronization sequence one-to-one, and an intra-group identification number corresponding to the primary synchronization sequence one-to-one. PCI is used to distinguish different LTE cells.

The C-RNTI is a dynamic identifier assigned to the UE by the base station, which uniquely identifies the UE under the air interface of a cell. However, the C-RNTI is valid only for the UE in the connected state.

Step 202, MME generates a handover request message according to the handover request message, and sends it to the target base station through the S1 interface. The handover request message includes the PCI of the source cell and the C-RNTI used by the UE in the source cell.

Wherein, the handover request message includes the context information of the UE in the source cell, the PCI of the source cell, and the C-RNTI used by the UE in the source cell. The context information, the PCI of the source cell, and the C-RNTI used by the UE in the source cell are respectively It is the same as the context information of the UE in the source cell, the PCI of the source cell, and the C-RNTI used by the UE in the source cell in the handover request message, and will not be repeated here.

Step 203, the target base station receives and stores the switch-in request message;

Step 204, after the S1 handover fails, the UE sends an RRC connection re-establishment request message to the target base station, and the RRC connection re-establishment request message includes the PCI of the source cell and the C-RNTI used by the UE in the source cell.

Wherein, the RRC connection re-establishment request message refers to the signaling sent by the UE to the target base station actively in order to restore the RRC connection with the LTE wireless network after the S1 handover fails, including the PCI of the source cell.

Step 205, when the handover request message and the RRC connection re-establishment request message match successfully, the target base station retrieves the context information of the UE in the source cell in the handover request message, and completes the RRC connection re-establishment of the UE in the target cell according to the context information process.

The successful match between the handover request message and the RRC connection re-establishment request message means that the PCI of the source cell in the hand-in request message is equal to the PCI of the source cell in the RRC connection re-establishment request message, and the UE in the hand-in request message is at the source The C-RNTI used in the cell is equal to the C-RNTI used by the UE in the source cell in the RRC connection re-establishment request message.

When the handover request message and the RRC connection re-establishment request message match successfully, the target base station determines that the context information in the hand-in request message is the context information of the UE that initiated the RRC connection re-establishment request in the source cell, so that according to the above context information, It more accurately schedules suitable radio resources for the UE, and completes the RRC connection re-establishment process of the UE in the target cell, thereby improving the success rate of the RRC connection re-establishment of the UE in the target cell.

Compared with the prior art, the RRC connection re-establishment method provided by Embodiment 1 of the present invention has the following beneficial effects:

In the prior art, after the S1 handover fails, since the identity of the UE cannot be identified, and the context information of the UE in the source cell in the handover request message cannot be obtained according to the identity of the UE, the target cell will reject the RRC connection re-establishment request of the UE, resulting in After X2 handover fails, the success rate of RRC connection re-establishment is low.

In the RRC connection re-establishment method provided in Embodiment 1 of the present invention, the hand-out request message, the hand-in request message and the RRC connection re-establishment request message all include the PCI of the source cell and the C-RNTI used by the UE in the source cell. After the S1 handover fails, when the PCI of the source cell in the handover request message is equal to the PCI of the source cell in the RRC connection re-establishment request message, and the C-RNTI used by the UE in the source cell in the handover request message is the same as When the C-RNTI used by the UE in the source cell in the RRC connection re-establishment request message is equal, the target base station determines that the source cell in the RRC connection re-establishment request message is the same cell as the source cell in the hand-in request message , and the UE in the RRC connection re-establishment request message is the same UE as the UE in the handover request message, which is equivalent to successfully identifying the identity of the UE; the target base station is more Accurately schedule appropriate resources for the UE, thereby effectively improving the success rate of RRC connection re-establishment.

Moreover, compared with the prior art, the RRC connection re-establishment method provided by the present invention only carries the PCI of the source cell and the C-RNTI used by the UE in the source cell in the handover request message and the handover request message, without adding S1 In addition, due to the increased success rate of RRC connection re-establishment, there is no need for the UE to re-search the network and access the LTE wireless network after the RRC connection re-establishment fails, which improves the efficiency of the LTE wireless network.

In addition, the method for re-establishing the RRC connection after the S1 handover failure provided by Embodiment 1 of the present invention can be realized only by upgrading the software, without adding hardware, and the upgrading operation is convenient.

In addition, before the source base station sends a handover request message to the MME through the S1 interface, the RRC connection re-establishment method may further include:

The UE sends a measurement report of the target cell to the source base station, where the measurement report includes the PCI, RSRP and RSRQ of the target cell;

When the target cell is the neighbor cell of the source cell and the target cell meets the handover conditions, the source base station sends a handover request message to the MME through the S1 interface. The target cell is the neighbor cell of the source cell, including the PCI of the target cell and the configuration of the neighbor cell of the source cell. The PCI of one of the neighboring cells is equal; the target cell meets the handover conditions, including that the RSRP of the target cell is higher than the RSRP of the source cell and the duration exceeds the first threshold and/or the RSRQ of the target cell is higher than the RSRQ of the source cell and the duration exceeds the first threshold Two thresholds.

It is worth noting that the source base station judges whether the target cell is a neighboring cell of the source cell and whether the target cell satisfies the handover condition according to the measurement report provided by the UE. When the target cell is a neighboring cell of the source cell and satisfies the above handover conditions, the source base station will handover the UE to the target cell, which can effectively avoid blind handover and improve handover success rate. Moreover, the handover request message sent by the source base station to the target base station through the S1 interface includes context information of the UE in the source cell, PCI of the source cell and/or C-RNTI used by the UE in the source cell.

Embodiment two

As shown in FIG. 3, Embodiment 2 of the present invention provides an RRC connection re-establishment system 30, which includes:

The source base station is configured to send a handover request message to the MME through the S1 interface, where the handover request message includes the PCI of the source cell and the C-RNTI used by the UE in the source cell.

MME, configured to receive and store the handover request message;

The MME is further configured to generate a handover request message according to the handover request message, and send it to the target base station through the S1 interface, the handover request message includes the PCI of the source cell and the C-RNTI used by the UE in the source cell.

The UE is configured to send an RRC connection re-establishment request message to the target base station after the S1 handover fails, and the RRC connection re-establishment request message includes the PCI of the source cell and the C-RNTI used by the UE in the source cell.

The target base station is configured to receive and store the hand-in request message.

The target base station is further configured to receive and store the RRC connection re-establishment request message after the S1 handover fails.

The target base station is further configured to retrieve context information of the UE in the source cell in the handover request message when the handover request message and the RRC connection re-establishment request message match successfully, and complete the process according to the context information The RRC connection re-establishment process of the UE in the target cell.

Wherein, the match between the cut-in request message and the RRC connection re-establishment request message is successful, including:

The PCI of the source cell in the handover request message is equal to the PCI of the source cell in the RRC connection re-establishment request message, and the C-RNTI used by the UE in the source cell in the handover request message is the same as the RRC The C-RNTI used by the UE in the source cell in the connection re-establishment request message is equal.

When the PCI of the source cell in the hand-in request message is equal to the PCI of the source cell in the RRC connection re-establishment request message, and the C-RNTI used by the UE in the source cell in the hand-in request message is the same as the RRC connection re-establishment When the C-RNTI used by the UE in the source cell in the request message is equal, the target base station determines that the source cell in the RRC connection re-establishment request message is the same cell as the source cell in the hand-in request message, and the RRC connection is re-established The UE in the request message and the UE in the hand-in request message are the same UE, which is equivalent to successfully identifying the identity of the UE; the target base station can more accurately schedule the UE for the UE based on the context information of the UE in the source cell in the hand-in request message Appropriate resources, thereby effectively improving the success rate of RRC connection re-establishment.

The RRC connection re-establishment system described in the second embodiment of the present invention has the same advantages as the RRC connection re-establishment method described in the first embodiment of the present invention over the prior art, and will not be repeated here.

In practical applications, in order to avoid UE ping-pong switching between the source cell and the target cell and improve the stability of the RRC connection, on the basis of the RRC connection re-establishment system described in Embodiment 2 of the present invention,

The UE is further configured to send a measurement report of the target cell to the source base station, where the measurement report includes the PCI, RSRP and RSRQ of the target cell; and

The source base station is further configured to receive and save the measurement report before sending a handover request message to the MME through the S1 interface, and then judge whether the target cell is a neighboring cell of the source cell and whether the target cell satisfies the following requirements according to the measurement report. switching conditions, where

When the PCI of the target cell is equal to the PCI of a neighboring cell in the neighboring cell configuration of the source cell, the target cell is a neighboring cell of the source cell; when the RSRP of the target cell is higher than the RSRP of the source cell and the duration exceeds the first threshold and /or when the RSRQ of the target cell is higher than the RSRQ of the source cell and the duration exceeds the second threshold, the target cell meets the handover condition.

It is worth noting that the purpose of setting the first threshold and the second threshold is: when the UE moves in the edge region between the source cell and the target cell, the size relationship between the RSRP of the target cell and the RSRP of the source cell, and The size relationship between the RSRQ of the target cell and the RSRQ of the source cell changes dynamically. When the first threshold and the second threshold are not set, the UE will frequently ping-pong between the target cell and the source cell, causing the UE to There is no stable RRC connection with the wireless network and cannot communicate normally. When the first threshold and the second threshold are set, the UE will not have a large or small relationship between the RSRP of the target cell and the RSRP of the source cell and/or the size relationship between the RSRQ of the target cell and the RSRQ of the source cell. Changes are switched immediately, but after a set period of delay, the signal received by the UE is stable before switching, which effectively reduces the probability of the above-mentioned ping-pong switching, thereby enhancing the stability and reliability of the LTE wireless network. Of course, the values of the first threshold and the second threshold may be the same or different, which is not limited in Embodiment 2 of the present invention.

The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto, and any changes or replacements within the technical scope disclosed in the present invention shall be covered within the protection scope of the present invention . Therefore, the protection scope of the present invention should be determined by the protection scope of the claims.

Claims (6)

1. a kind of RRC connection reconstructions cube method, it is characterised in that methods described includes：

MME is received and is preserved source base station and cuts out request message by what S1 mouths sent, and the request message that cuts out is including cell-of-origin C-RNTI used in cell-of-origin of PCI and UE；

MME generates incision request message according to the request message that cuts out, and is sent to target BS, the incision by S1 mouths Request message includes the C-RNTI of the PCI and UE of cell-of-origin used in cell-of-origin；

Target BS receives and preserves the incision request message；

After S1 handoff failures, UE to target BS sends RRC connection re-establishment request messages, and the RRC connection re-establishments please Message is asked to include the C-RNTI of the PCI and UE of cell-of-origin used in cell-of-origin；

When the match is successful for the incision request message and the RRC connection re-establishments request message, target BS is cut described To enter retrieved in request message contextual informations of the UE in cell-of-origin, and UE is completed in Target cell according to the contextual information RRC connection re-establishment flow processs.

2. RRC connection reconstructions cube method according to claim 1, it is characterised in that the incision request message and described The match is successful for RRC connection re-establishments request message, including：

The PCI of the cell-of-origin in the PCI of the cell-of-origin in the incision request message and the RRC connection re-establishments request message It is equal, and C-RNTIs of the UE used in cell-of-origin in the incision request message disappear with RRC connection re-establishments request C-RNTIs of the UE in breath used in cell-of-origin is equal.

3. RRC connection reconstructions cube method according to claim 1 and 2, it is characterised in that source base station by S1 mouths to MME sends and cuts out before request message, and methods described also includes：

UE sends the measurement report of Target cell to source base station, PCI, RSRP of the measurement report including Target cell and RSRQ；

Source base station is received and preserves the measurement report, then judges whether Target cell is cell-of-origin according to the measurement report Adjacent area and Target cell whether meet switching condition, wherein

When the PCI of Target cell is equal with the PCI of an adjacent area in the neighbor cell configuration of cell-of-origin, Target cell is cell-of-origin Adjacent area；When Target cell RSRP higher than cell-of-origin RSRP and the persistent period exceed and first threshold and/or work as Target cell RSRQ higher than cell-of-origin RSRQ and the persistent period exceed Second Threshold when, Target cell meets switching condition.

4. a kind of RRC connection reconstructions erection system, it is characterised in that the system includes:

Source base station, for sending to MME by S1 mouths request message is cut out, the PCI for cutting out request message including cell-of-origin C-RNTI with UE used in cell-of-origin；

MME, for receiving and preserves and described cuts out request message；

The MME, is additionally operable to generate incision request message according to the request message that cuts out, and is sent to target base by S1 mouths Stand, the incision request message includes the C-RNTI of the PCI and UE of cell-of-origin used in cell-of-origin；

UE, for after S1 handoff failures, to target BS RRC connection re-establishment request messages, the RRC connection reconstructions being sent Vertical request message includes the C-RNTI of the PCI and UE of cell-of-origin used in cell-of-origin；And

Target BS, for receiving and preserves the incision request message；

The target BS, is additionally operable to after S1 handoff failures, receives and preserve the RRC connection re-establishments request message；

The target BS, be additionally operable to when it is described incision request message and the RRC connection re-establishments request message the match is successful When, contextual informations of the UE in cell-of-origin is retrieved in the incision request message, and UE is completed according to the contextual information In the RRC connection re-establishment flow processs of Target cell.

5. RRC connection reconstructions erection system according to claim 4, it is characterised in that the incision request message and described The match is successful for RRC connection re-establishments request message, including：

The PCI of the cell-of-origin in the PCI of the cell-of-origin in the incision request message and the RRC connection re-establishments request message It is equal, and C-RNTIs of the UE used in cell-of-origin in the incision request message disappear with RRC connection re-establishments request C-RNTIs of the UE in breath used in cell-of-origin is equal.

6. RRC connection reconstruction erection systems according to claim 4 or 5, it is characterised in that

The UE, is additionally operable to send the measurement report of Target cell to source base station, and the measurement report includes Target cell PCI, RSRP and RSRQ；And

The source base station, was additionally operable to before request message is cut out to MME transmissions by S1 mouths, received and preserve the measurement report Accuse, then judge whether Target cell is whether the adjacent area of cell-of-origin and Target cell meet switching according to the measurement report Condition, wherein

When the PCI of Target cell is equal with the PCI of an adjacent area in the neighbor cell configuration of cell-of-origin, Target cell is cell-of-origin Adjacent area；When Target cell RSRP higher than cell-of-origin RSRP and the persistent period exceed and first threshold and/or work as Target cell RSRQ higher than cell-of-origin RSRQ and the persistent period exceed Second Threshold when, Target cell meets switching condition.