WO2011020382A1

WO2011020382A1 - Method and device for preventing switching user to cell in barred state

Info

Publication number: WO2011020382A1
Application number: PCT/CN2010/074719
Authority: WO
Inventors: 胡海鹏; 易鸿锋; 张现周; 赵亮
Original assignee: 中兴通讯股份有限公司
Priority date: 2009-08-19
Filing date: 2010-06-29
Publication date: 2011-02-24
Also published as: CN101998484B; CN101998484A

Abstract

A method for preventing switching a user to a cell in a barred state is disclosed. The method comprises: an Evolution Node B (eNB) receives measured information of adjacent cells reported by a user terminal, selects a cell of best quality as a candidate target cell, and detects whether the present information of a barred state of the candidate target cell is stored by itself. If no, the eNB notices the user terminal to report the information of the barred state of the candidate target cell, and restricts the user terminal from being switched to the candidate target cell when judging that a flag bit of the information of the barred state reported by the user terminal is barred. An eNB is also disclosed. The technical solution improves the switching success rate of the user and reduces the call drop rate of the user.

Description

Method and device for preventing user from switching to prohibited state cell

The present invention relates to the field of mobile communication technologies, and in particular, to a method and apparatus for preventing a user from switching to a forbidden state cell. Background technique

With the development of the mobile communication industry and the increasing demand for network quality, the quality of service of wireless networks is becoming more and more important. One aspect of the quality of network services is the drop rate. Especially in the process of switching, how to reduce the call drop rate of users has become a problem that mobile systems must consider.

The LTE (Long Term Evolution) system is characterized by a large data volume service and a high quality of service experience. Therefore, how to reduce the call drop rate and handover delay of the user during the handover process is critical.

In the LTE system, there is a handover between the Χ2 interface and the S1 interface, and the handover process refers to a process in which a UE (Ueser Equipment, User Equipment) switches from a source evolved Node B (eNB) to a cell controlled by the target eNB.

When the UE performs cell handover, it usually includes a handover preparation phase and a handover execution phase. In the handover preparation phase, the mobile terminal monitors the radio channel condition in real time. When the radio channel condition is changed, the UE notifies the source eNB, and the source eNB sends a measurement configuration to notify the UE to perform measurement, and the UE sends the measurement report to the source eNB after performing the measurement. The source eNB selects a suitable target cell according to a certain algorithm, and then sends a handover request message to the target eNB to which the target cell belongs, requesting the target eNB to reserve corresponding resources for the UE, and if the target eNB has idle resources, send a handover to the source eNB. Reply to the message, otherwise return a switch failure message.

After the handover preparation is completed, the source eNB sends a handover command to the UE, and the UE disconnects from the source eNB. The wireless connection, switching to the target eNB, establishes a wireless connection with the target eNB.

The current method for the handover is mainly: when the signal of the serving cell is weak, the network side carries the neighboring cell list of the serving cell in the measurement control message and sends it to the terminal, and the terminal initiates measurement in each neighboring cell in the list. And reporting the measurement report, the network side performs the handover decision, and selects a cell with better signal quality to perform handover.

Or, the source eNB sends a handover request message to the multiple target eNBs, where the message carries the cell identifier of the preferred cell, and the source eNB receives the message returned by the target eNB to which the preferred cell belongs, where the message carries the preferred cell allocation The source eNB sends the resource to the user equipment, and the user equipment accesses the wireless network to complete the handover.

Or, in the handover preparation phase, the source eNB determines the target node and a set of downlink nodes for downlink data transmission according to the measurement information, and requests the target node and the downlink node to allocate the same resource to the UE, and the downlink node provides the downlink after the resource allocation succeeds. The service then switches the uplink to the target node. After the downlink route also switches to the target node, the other downlink node is notified to release the resources allocated for the UE, thereby solving the method of switching the upper and lower simultaneous switching in the general switching service. The impact of the business.

The above method does not consider the cell barred (CellBarred) information of the target cell when selecting the target cell, that is, the effect of the cell with the flag of the CellBarred information being barred (forbidden) on the handover success rate and the handover delay. The CellBarred information of the cell is indicated in the cell system broadcast message, and is used to control whether the cell allows the user to access. If the flag of the CellBarred information is barred, the cell does not allow any user to access for a period of time. Therefore, the source eNB When the target cell is selected, if the cell of the target cell is not considered, and the barred cell is used as the handover target cell, the success rate of the handover and the handover delay are greatly reduced, which affects the quality of the call.

When the user is in the handover area, the user reports the report, and the source eNB selects an optimal cell as the target cell for handover, and then notifies the user to perform handover. But if you choose When the cell is considered, the cell's CellBarred state is not considered, and a barred cell is selected. When the UE accesses, the cell is found to be prohibited from accessing, and then the source eNB is notified, and the source eNB must reselect an optimal target cell. At this time, a barred cell is still selected, and the source eNB continues to reselect an optimal target cell. In the long run, the success rate of the user handover is greatly reduced, and the handover delay is increased. Summary of the invention

The present invention provides a method and apparatus for preventing a user from switching to a forbidden state cell, which is used to solve the problem that the target cell to be switched by the UE is in a forbidden state, and cannot be successfully switched. The problem of falling rates.

In order to solve the above problems, the technical solution of the present invention is implemented as follows:

A method for preventing a user from switching to a forbidden state cell, the method comprising:

The eNB selects a candidate target cell according to the measurement information of the neighboring cell reported by the user terminal, and restricts the user terminal from switching to the candidate target cell when the flag of the current forbidden state information of the candidate target cell is learned to be disabled.

The method for obtaining the flag of the current forbidden state information of the candidate target cell is forbidden: the eNB detects the forbidden state information of the candidate target cell that is stored by the eNB, and determines that the flag of the detected forbidden state information is forbidden; Or,

The user terminal reports the prohibition status information to the eNB, and the eNB determines that the flag bit of the reported prohibited status information is prohibited.

The method further includes:

When the flag of the current forbidden state information of the candidate target cell is not forbidden, the cell handover request message is sent to the target eNB to which the candidate target cell belongs.

The method further includes:

When the eNB establishes an X2 port with the target eNB to which the candidate target cell belongs, the eNB stores mutually prohibited state information of each cell in the eNB. Before the user terminal reports the forbidden state information, the method further includes: determining that the eNB does not store the prohibited state information of the candidate target cell, and the candidate target cell is not in the neighbor list stored by the eNB.

The forbidden state information reported by the user terminal is obtained by reading the broadcast information of the candidate target cell.

An eNB includes:

a measurement information receiving module, configured to select a candidate target cell according to measurement information of a neighboring cell reported by the user terminal;

And a detection result processing module, configured to learn a flag bit of the current prohibited state information of the candidate target cell; and when the flag bit is disabled, restrict the user terminal from switching to the candidate target cell.

The detection result processing module is further configured to: when the flag of the forbidden state information is learned, detect the prohibited state information reported by the user terminal, and determine that the flag of the forbidden state information is prohibited; or

The eNB further includes a forbidden state information detecting module, configured to detect whether the prohibited state information of the candidate target cell is stored in the eNB, and notify the detection result processing module to detect the forbidden state information when not detected.

The detection result processing module is further configured to: when the flag of the current forbidden state information of the candidate target cell is not forbidden, send a cell handover request message to the target eNB to which the candidate target cell belongs.

The detection result processing module is further configured to: before the user terminal reports the forbidden state information, determining that the eNB does not store the forbidden state information of the candidate target cell, and the candidate target cell is not in the neighboring node of the eNB. In the list of districts.

Compared with the prior art, the present invention has the following advantages:

The method provided by the present invention, by knowing in advance the forbidden state of the target cell to be switched, Therefore, the cell that switches the user to the forbidden state can be restricted, the handover success rate of the user is improved, the handover delay of the user is reduced, and the quality of service of the user is further improved. DRAWINGS

1 is a flowchart of a method for preventing a user from switching to a forbidden state cell according to the present invention; FIG. 2 is a flowchart of a method for preventing a user from switching to a forbidden state cell according to Embodiment 1 of the present invention;

3 is a flowchart of a method for preventing a user from switching to a forbidden state cell according to Embodiment 2 of the present invention;

FIG. 4 is a structural diagram of an eNB provided by the present invention. detailed description

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

The present invention provides a method and apparatus for preventing a user from switching to a forbidden state cell, which is used to solve the problem that the target cell to be switched by the UE is in a forbidden state, and cannot be successfully switched, thereby causing a handover success rate. The problem of falling.

Specifically, the present invention provides a method for preventing a user from switching to a forbidden state cell. As shown in FIG. 1, the method includes the following steps:

Step S101: The source eNB receives the measurement information of the neighboring cell reported by the user terminal, and selects a cell with the best quality as the candidate target cell from the neighbor cell measurement information reported by the user.

Step S102: The source eNB detects whether the current CellBarred information of the candidate target cell is stored, and if not, notifies the user terminal to report the CellBarred information of the candidate target cell, and determines that the flag of the CellBarred information reported by the user terminal is barred. When the user terminal is restricted from switching to the candidate target cell.

Further, when the source eNB detects the CellBarred letter in which the candidate target cell is stored, In the case of the information, it is determined whether the flag of the CellBarred information is barred, and if so, the user terminal is restricted from switching to the candidate target cell, otherwise, the cell handover request message is sent to the target eNB to which the candidate target cell belongs.

When the source eNB establishes the X2 interface with the target eNB to which the candidate target cell belongs, the source eNB stores mutually prohibited state information of each cell in the eNB, and transmits the received eNB due to the change of the prohibition state information of the internal cell. When the message is updated, the stored forbidden status information is updated.

Further, when the source eNB does not store the CellBarred information of the candidate target cell, if the candidate target cell is not in the neighbor list stored by itself, the ANR process is started to notify the user terminal that the CellBarred information in the candidate target cell broadcast information is ECGI information, and the candidate target cell is added to the neighbor list of its own storage.

The method provided by the present invention can restrict the user to switch to the cell with the CellBarred flag bit barred by knowing the CellBarred information of the target cell to be switched in advance, thereby improving the handover success rate of the user and reducing the handover delay of the user. Improve the quality of service for users. The specific implementation process of the method for prohibiting the state cell.

Embodiment 1 This embodiment is implemented based on the candidate target cell to be switched selected by the source eNB exists in the neighbor list stored by the source eNB.

Specifically, the embodiment implements a process for preventing a user from switching to a forbidden state cell. As shown in FIG. 2, the method includes the following steps:

In step S201, the UE monitors the service quality of the current cell and the neighboring cell in real time. When the service quality of the current cell is lower than that of the neighboring cell, the event is reported to the source eNB to which the UE belongs, and the measurement information is reported together. . In this embodiment, the measurement information includes measurement results for multiple neighboring cells. Step S202: The source eNB selects a cell with the best service quality, that is, the strongest signal, as the candidate target cell according to the measurement result reported by the UE.

Step S203: The source eNB determines whether it stores the CellBarred information of the candidate target cell, and if yes, performs step S206; otherwise, performs step S204.

Wherein, in the case that the source eNB has stored the CellBarred information of the candidate target cell when the handover is determined, the situation occurs when the source eNB and the target eNB to which the candidate target cell belongs are established, and the two eNBs that are required to establish X2 transmit the CellBarred information of each other to other side.

The following process is illustrated by a specific example of the existence of X2 between eNBs:

(1) The eNB1 sends an X2 setup request message to the eNB2, where the message includes the CellBarred information of each cell in the eNB1;

(2) The eNB2 sends an X2 Setup Request Response message to the eNB1, where the message includes CellBarred information of each cell in the eNB2.

It should be noted that, when the CellBarred of a certain cell in the eNB of the X2 changes, the eNB in which the changed cell informs another eNB through the X2 update message to ensure that the CellBarred information stored in the eNB is the latest information.

Step S204: The source eNB notifies the UE of the CellBarred information in the candidate target cell broadcast message.

Step S205: After receiving the notification message of the source eNB, the UE reads the broadcast information of the candidate target cell, acquires the CellBarred information of the cell, and reports the information to the source eNB.

Step S206: The source eNB determines whether the flag bit of the CellBarred information of the candidate target cell is barred. If the step S207 is performed, otherwise, step S208 is performed.

Step S207: The source eNB restricts the UE from switching to the candidate target cell, and selects the best quality cell in the remaining cell as the candidate target cell according to the measurement result reported by the UE, and returns to step S203.

Step S208: The source eNB sends a handover request to the target eNB to which the candidate target cell belongs. Ask for the message, enter the switch preparation state.

Embodiment 2: This embodiment is implemented based on the candidate target cell selected by the source eNB that is not present in the neighboring cell list stored by the source eNB.

In step S301, the UE monitors the service quality of the current cell and the neighboring cell in real time. When the service quality of the current cell is lower than that of the neighboring cell, the event is reported to the source eNB to which the UE belongs, and the measurement information is reported together. The measurement information includes measurement results for a plurality of neighboring cells.

Step S302: The source eNB selects a cell with the best quality of service as a candidate target cell according to the measurement result reported by the UE.

Step S303: The source eNB determines whether the CellBarred information of the candidate target cell is stored, and if yes, step S304 is performed; otherwise, step S305 is performed.

In this step, if the source eNB stores the CellBarred information of the candidate target cell, the manner of acquiring the CellBarred information is the same as that in the first embodiment, and is not described here.

Step S304: The source eNB determines whether the flag bit of the stored CellBarred information of the candidate target cell is barred, and if yes, performs step S308; otherwise, performs step S309.

Step S305: The source eNB starts an ANR process, and notifies the UE of the ECGI information and the CellBarred information of the candidate target cell.

Step S306, after receiving the notification message of the source eNB, the UE reads the broadcast message of the candidate target cell, acquires the ECGI information of the cell and the CellBarred information, and reports the obtained information to the source eNB together;

Step S307: The source eNB adds the candidate target cell to the neighboring cell list, and determines whether the candidate target cell is a barred state cell according to the flag of the CellBarred information reported by the UE. If yes, go to step S308; otherwise, go to step S309.

Step S308: The source eNB restricts the UE from switching to the candidate target cell, and selects the best quality cell in the remaining cell as the candidate target cell according to the measurement result reported by the UE, and returns to the step. S303.

Step S309: The source eNB sends a handover request message to the target eNB to which the candidate cell belongs, and enters a handover preparation state.

This embodiment is different from the first embodiment in that the solution can be implemented in combination with the ANR process, and the UE does not need to additionally increase the interaction between the UE and the eNB, because the UE needs to read the broadcast information of the neighboring cell to obtain the ECGI when the neighbor relationship is acquired, as long as the UE When reporting ECGI, you can go along with the cell CellBarred information.

In the embodiment of the present invention, the forbidden state of the target cell to be switched to is obtained in advance, so that the user can be restricted from switching to the forbidden cell, the handover success rate of the user is improved, and the handover delay of the user is reduced, thereby further improving the user's handover time. service quality.

The present invention also provides an eNB, as shown in FIG. 4, including:

The measurement information receiving module 410 is configured to receive measurement information of a neighboring cell reported by the user terminal, and select a cell with the best quality as the candidate target cell;

The forbidden state information detecting module 420 is configured to detect whether the CellBarred information of the candidate target cell is stored in the eNB;

The detection result processing module 430 is configured to notify the user terminal to report the CellBarred information of the candidate target cell when the forbidden state information detecting module 420 detects that the CellBarred information is not stored, and determine that the flag of the CellBarred information of the user terminal is >3⁄4 When barred, the user terminal is restricted from switching to the candidate target cell.

In fact, regardless of whether the CellBarred information is stored by itself, the detection result processing module 430 can finally obtain the CellBarred information, and when the flag of the current CellBarred information of the candidate target cell is learned to be prohibited, the user terminal is restricted from switching to the location. The candidate target cell is described.

Specifically, the detection result processing module 430 is further configured to: when the forbidden state information detecting module 420 detects that the CellBarred information is stored, determine whether the flag bit of the CellBarred information is Barred, if yes, restricts the user terminal from switching to the candidate target cell, otherwise, sends a cell handover request message to the target eNB to which the candidate target cell belongs.

The detection result processing module 430 is further configured to: when it is determined that the flag bit of the CellBarred information reported by the user terminal is notBarred, send a cell switching request message to the target eNB to which the candidate target cell belongs.

The detection result processing module 430 notifies the CellBarred information and the ECGI information of the candidate target cell on the user terminal when the forbidden state information detecting module 420 detects that the CellBarred information is not stored, and determines that the candidate target cell is not in the neighboring cell list stored by the eNB. And adding the candidate target cell to the neighbor list. The spirit and scope of the invention. Thus, it is intended that the present invention cover the modifications and modifications of the invention

Claims

Claim

The evolved Node B eNB selects a candidate target cell according to the measurement information of the neighboring cell reported by the user terminal, and restricts the user terminal from switching to the foregoing when the flag of the current forbidden state information of the candidate target cell is learned to be prohibited. Candidate target cell.

2. The method according to claim 1, wherein the method for knowing that the flag of the candidate target cell forbidding state information is prohibited is:

The eNB detects the forbidden state information of the candidate target cell that is stored by itself, and determines that the flag of the detected forbidden state information is prohibited; or

The method according to claim 2, wherein the method further comprises: when the flag of the current forbidden state information of the candidate target cell is not forbidden, sending to the target eNB to which the candidate target cell belongs Cell handover request message.

The method according to any one of claims 1 to 3, wherein the method further comprises:

When the eNB establishes the X2 interface with the target eNB to which the candidate target cell belongs, the eNB stores mutually prohibited state information of each cell in the eNB.

The method according to claim 2, wherein before the user terminal reports the forbidden state information, the method further includes:

Determining that the eNB does not store the prohibition status information of the candidate target cell, and the candidate target cell is not in the neighbor list stored by the eNB.

The method according to claim 5, wherein the forbidden state information reported by the user terminal is obtained by reading broadcast information of the candidate target cell.

7. An eNB, comprising:

The eNB according to claim 7, wherein the detection result processing module is further configured to: when the flag of the forbidden state information is learned, detect the prohibited state information reported by the user terminal, and determine the The flag of the prohibited status information is forbidden; or,

The eNB according to claim 8, wherein the detection result processing module is further configured to: when the flag of the current prohibited state information of the candidate target cell is not forbidden, to the candidate target cell The belonging target eNB transmits a cell handover request message.

The eNB according to any one of claims 7 to 9, wherein the detection result processing module is further configured to: before the user terminal reports the prohibition status information, determining that the eNB does not store the candidate The prohibited state information of the target cell, and the candidate target cell is not in the neighbor list stored by the eNB.