WO2010105562A1

WO2010105562A1 - Method for implementing cell handover and system, relay equipment thereof

Info

Publication number: WO2010105562A1
Application number: PCT/CN2010/071102
Authority: WO
Inventors: 汪颖; 高卓
Original assignee: 大唐移动通信设备有限公司
Priority date: 2009-03-17
Filing date: 2010-03-17
Publication date: 2010-09-23
Also published as: CN101841824A

Abstract

A method, system and relay equipment for implementing cell handover are provided in embodiments of the present invention. The method includes that: a source Relay Node RN receives a measurement report reported by a User Equipment UE, and then according to the measurement report, judges whether to implement the cell handover or not, if yes, the source RN exchanges handover information with a target node via a source evolved Node Base-station eNB. The system includes: a source RN, a source eNB and a target node. The relay equipment includes a handover judgement module and a handover module. Application of the present invention can implement the cell handover in a mobile communication system with RN, and ensure a faster speed of the cell handover.

Description

Method, system and relay device for realizing cell handover

Technical field

The present invention relates to the field of mobile communications technologies, and in particular, to a method, system, and relay device for implementing cell handover. Background of the invention

Higher peak data rates and cell throughput will be provided in future mobile communication systems, such as the Beyond Three Generation (B3G) system or the Long Term Evolution (LTE) system or the Advanced Long Term Evolution (LTE-A) system. , but also need more bandwidth. At present, there is very little unallocated bandwidth below 2 GHz. Some or all of the bandwidth required by B3G systems can only be found in higher frequency bands, for example, above 3 GHz. The higher the frequency band, the faster the radio wave propagation is attenuated and the shorter the transmission distance. Therefore, in the same coverage area, more base stations are required to ensure continuous coverage. Since base stations usually have higher cost, this will undoubtedly increase the cost of the network. In order to solve the problem of network cost, various vendors and standardization organizations have begun to study the introduction of relay nodes (RNs) into future mobile communication systems to expand coverage.

FIG. 1 is a schematic structural diagram of a communication system provided with an RN.

As shown in FIG. 1, each gateway (Gateway) communicates with its subordinate eNB through an S1 interface, and each eNB communicates through an X2 interface. Each eNB is provided with an RN, and the eNB communicates with the RN under it through the Y3 interface.

Currently, in future mobile communication systems such as the LTE system and the LTE-A system, there is no radio interface between the RN and the core network, but access to the core network through a donor cell. Each RN can control one or more cells, each with independent PCI, synchronization channels, and reference signals.

As the UE moves from one cell to another, the UE is required to be in each cell. Switch between. For the mobile communication system in which the RN is set, how to switch between cells is not yet proposed. Summary of the invention

In view of this, an object of the embodiments of the present invention is to provide a method, a system, and a relay device for implementing cell handover, so that cell handover is implemented in a mobile communication system in which an RN is set, and a faster handover speed is ensured.

To achieve the above objective, the technical solution of the embodiment of the present invention is specifically implemented as follows: A method for implementing cell handover, the method includes:

The source relay device receives the measurement report reported by the user equipment UE, and determines whether to perform cell handover according to the measurement report. If the handover is performed, the source RN exchanges a message with the target node through the source base station eNB.

A system for implementing cell handover, the system comprising:

The source RN receives the measurement report reported by the UE, and determines whether to perform the cell handover according to the measurement report. If the handover is performed, the source eNB exchanges a message with the target node.

The source eNB forwards the handover message between the source RN and the target node;

The target node determines whether to accept the UE, and exchanges a message with the source RN through the source eNB.

A relay device for implementing cell handover, the device comprising a handover decision module and a handover module;

The handover decision module is configured to receive a measurement report reported by the UE, determine, according to the measurement report, whether to perform cell handover, and if yes, send a handover indication to the handover module;

The switching module, after receiving the handover indication, exchanges a message with the target node through the source eNB.

It can be seen from the above technical solutions that the technical solution provided by the present invention is determined by the source RN. The quantity report is used to perform the cell handover decision. After the decision is made that the handover is required, the source eNB only needs to exchange the message with the target node, and the measurement report is not sent to the eNB, thereby reducing the data transmission amount, thereby improving the handover speed, and The wireless interface that communicates with the eNB through the RN can implement the exchange of the message with the target node through the source eNB, and the other RN is not required to be set, so that the structure of the RN is single. BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a schematic diagram showing the composition of a communication system provided with an RN.

2 is a schematic diagram of a mobile communication system connection in which an RN is set.

FIG. 3 is a flowchart of a cell handover method in a seventh case provided by the present invention.

FIG. 4 is a schematic diagram of a system composition for implementing cell handover according to the present invention.

FIG. 5 is a structural diagram of a relay device for implementing cell handover according to the present invention. Mode for carrying out the invention

The present invention will be further described in detail below with reference to the accompanying drawings.

With the rapid development of mobile communication systems, the future development trend of mobile communication systems is that the cell radius is getting smaller and smaller, and the moving speed of user terminals is increasing, which requires the handover process to be as fast as possible. The present invention proposes that after receiving the measurement report reported by the UE, the source RN does not send the measurement report to the source eNB, but the source RN performs a handover decision according to the measurement report, and if it is determined that the handover needs to be performed, the source is used. The RN exchanges a message with the target node through the source eNB, thereby implementing cell handover. The handover message includes various messages for implementing the handover, for example, a handover request message, a handover request acknowledgement message, and the like. The RN of the present invention stores the context information of the UE and the neighbor cell relationship of each cell that the RN governs, and has the wireless The function of the resource management (RRM) can be based on the measurement report reported by the UE and the relationship between the neighboring cells. Now switch the judgment.

The present invention is applied to a mobile communication system provided with an RN, and is implemented by changing a handover decision function performed by an eNB in a mobile communication system in which an existing RN is not set to an RN, and is capable of adapting to a new type of mobile communication system provided with an RN. The structure of the mobile communication system improves the speed of cell handover. Specifically, since the RN can perform the handover decision according to the measurement report reported by the UE, if the handover is allowed, the handover request message only needs to be sent to the eNB, and the measurement report is not required to be transmitted to the eNB, thereby reducing the data transmission amount and improving the data transmission. Speed, which improves the cell switching speed, while also saving resources such as bandwidth.

The eNB stores information about all the RNs connected to it, for example, the identity of each cell that is governed by each RN. The eNB internally stores a specific identifier, and the specific identifier can distinguish which cells belong to the RN management and which are the eNB. For example, the specific identifier may be an access mode of each cell, and if it is a radio access mode, the cell is an RN management, and if it is a wired access mode, the cell is directly managed by the eNB. Each eNB also needs to exchange its managed RN information, such as a cell identifier. If an X2 interface exists between the eNBs, the RN information can be exchanged through the X2 interface. If the X2 interface does not exist, the core network device such as the MME can be utilized through the S1 interface. Interact RN information. Each cell managed by the RN has a Cell Global Identifier (CGI) identifier. The CGI identifier is 28 bits, where 20 bits is the identifier of the serving eNB, and the other 8 bits is the cell ID. The CGI identifier of each cell is stored in the eNB, and can be correctly addressed by CGI.

Referring to FIG. 2, in practical applications, there are seven different handover situations in the UE during the mobile process, namely:

In the first case, the UE switches from the first base station eNB1 to the second base station eNB2, in which case both the source node and the target node are base stations. In the first case, the existing handover method may be adopted, and the source eNB performs a handover decision according to the measurement report reported by the UE, and the UE exchanges a message with the target eNB through the source eNB to implement handover.

In the second case, the UE switches from eNB1 to the RN under the jurisdiction of eNB1, in which case the source node is the eNB and the target node is the RN.

In the second case, the source _e NB performs a handover decision according to the measurement report reported by the UE, and the UE exchanges a message with the target RN by the source eNB to implement the handover, that is, the UE sends a handover request message to the eNB1, and the eNB1 sends the handover request message. Forwarding to the RN under the jurisdiction of the eNB1, the eNB1 receives the handover request acknowledgement message or the handover request failure message sent by the RN and forwards the handover request message to the UE.

In the third case, the UE switches from the RN under the jurisdiction of eNB1 to the eNB1, in which case the source node is the RN and the target node is the eNB.

In the fourth case, the UE switches from the first relay eNB1RN1 belonging to the eNB1 to the second relay eNB1RN2 also belonging to the eNB1, in which case the source node and the target node are both RNo.

In the fifth case, the UE switches from eNB1 to the first relay eNB2RN1 or the second relay eNB2RN2 under the jurisdiction of another base station eNB2, in which case the source node is the eNB and the target node is the RN.

In the fifth case, the source eNB performs a handover decision according to the measurement report reported by the UE, and the UE exchanges a message with the target RN by the source eNB to implement the handover, that is, the source eNB forwards the handover message between the UE and the target eNB, where the target eNB is The handover message is forwarded between the target RN and the source eNB.

In the sixth case, the UE switches from eNB1RN1 or eNB1RN2 to eNB2, in which case the source node is the RN and the target node is the eNB.

In the seventh case, the UE switches from eNB1RN1 or eNB1RN2 to eNB2RN1 or eNB2RN2, in this case, both the source node and the target node are RNs.

For the fourth, fourth, sixth, and seventh cases, the source node is the RN, and the source RN performs the handover decision according to the measurement report reported by the UE. If the handover is required, the source eNB exchanges the message with the target node. Thereby switching is achieved.

In an actual application, the source RN sends a handover request message to the source eNB, and the source eNB identifies the target node according to the handover request message, that is, identifies that the target cell is directly managed by the source eNB, and is managed by the RN of the source eNB. The eNB other than the source eNB is directly managed or managed by an RN subordinate to the target eNB other than the source eNB.

Since the seventh case involves more nodes, the process of switching is the most complicated. The seventh case is taken as an example to illustrate the method of implementing handover.

If the eNB1 and the eNB2 are provided with the interface X2 that communicates with each other, the handover is implemented based on the X2 interface, that is, the eNB1 and the eNB2 exchange the message directly through the X2 interface; if the eNB1 and the eNB2 do not have the X2 interface, the handover is implemented based on the S1 interface, that is, The eNB1 and the eNB2 send the handover message to the upper layer through the S1 interface, and then the high layer forwards the handover message to the other one of the eNB1 and the eNB2 through the S1 interface, where the upper layer is usually the MME.

3 is a flowchart of a cell handover method in a seventh case provided by the present invention, which implements handover based on an X2 interface. As shown in FIG. 7, the method includes:

Step 301: The UE sends a measurement report to the source RN.

In this step, the UE performs channel quality measurement according to the pre-configured parameters, and reports the measurement result to the source RN.

Step 302: The source RN determines whether to initiate the handover according to the measurement report of the UE and the RRM algorithm stored by the source RN. If yes, go to step 303. Otherwise, the source RN receives the measurement report reported by the UE next time and returns to step 302.

Step 303: The source RN sends a handover request message to the source eNB.

The handover request message carries the ID of the target RN, the bearer message of the UE, and the RRC. The context message, the handover area restriction message, the security information, and the UE history information, etc., step 304, the source eNB forwards the handover request message to the target eNB.

Step 305: The target eNB forwards the handover request message to the target RN.

Step 306: The target RN performs an admission decision, and sends a handover message carrying the decision result to the target eNB.

In this step, if the target RN accepts the UE, it returns a handover request acknowledgement message to the target eNB and reserves the corresponding resource. If the UE is not accepted, the handover request failure message is returned to the target eNB, and the failure cause value is carried therein. .

The handover request acknowledgement message carries bearer information that allows handover, and information that needs to be delivered to the UE.

Step 307: The target eNB sends a handover message carrying the decision result to the source eNB.

Step 308: The source eNB sends a handover message carrying the decision result to the source RN.

In step 303 to step 308, the source RN exchanges a message with the target node (ie, the target RN) through the source eNB, where the handover message includes a handover request message or a handover request acknowledgement message or a handover request failure message.

Step 309: If the handover message carrying the decision result is a handover request failure message, the source RN ends the current handover. If the handover message carrying the decision result is a handover request acknowledgement message, the source RN sends a handover command message to the UE.

The handover command message in this step carries information that the target RN needs to deliver to the UE.

Step 310: The UE accesses the target RN according to the handover command message.

Step 311: The UE sends a handover complete message to the target RN.

Step 312: The target RN forwards the handover complete message to the target eNB.

Steps 313-314, the target eNB initiates a path switching process to the MME.

In this step, after receiving the message that the target eNB initiates the path switching process, the MME switches. The user plane path, and after the handover is completed, sends a path switching confirmation message to the target eNB. Step 315: The target eNB initiates a resource release process to the source eNB, and the source eNB initiates a resource release process to the source RN, and the source eNB and the source RN release the resources occupied by the UE.

When the handover is implemented based on the S1 interface, the source eNB and the target eNB communicate with the MME in the core network through the S1 interface, and the MME forwards the handover message. For example, the source eNB receives the UE context release message from the source MME, and initiates the message to the source RN. During the resource release process, the source RN releases all resources occupied by this UE.

The switching process in the third, fourth, and sixth cases is the same as the switching process in the seventh case. The following only describes the differences:

The switching process in the third case includes:

Steps 401-402: In the same steps 301-302, if the source RN determines that the handover is initiated, step 403 is performed; otherwise, the process returns to step 402.

Step 403: The source eNB is the same eNB as the target eNB. Therefore, the source RN sends a handover request message to the source eNB, and the source eNB makes an admission decision, and sends a handover message carrying the decision result to the source RN.

Step 404, the same step 309.

Step 405: The UE accesses the source eNB (ie, the target eNB) according to the handover command message. After the access succeeds, the UE sends a handover complete message to the source eNB, and the source eNB initiates a path switching process to the MME, and the source eNB initiates a resource release process to the source RN. The source RN releases the corresponding resource.

The switching process in the fourth case includes:

Steps 501~502: Same steps 301~302.

Step 503: The source RN sends a handover request message to the source eNB, and the source eNB forwards the handover request message to the target RN, and the target RN makes an admission decision, and sends a handover message carrying the decision result to the source eNB, and the source eNB The handover message carrying the decision result is sent to the source RN.

Step 504, the same as step 309. Step 505: The UE accesses the target RN according to the handover command message. After the access succeeds, the UE sends a handover complete message to the target RN. The target RN forwards the handover complete message to the source eNB, and the source eNB initiates a path switching process to the MME. The source RN initiates a resource release process, and the source RN releases the corresponding resource.

The handover process in the sixth case includes:

Steps 601~602: Same steps 301~302.

Step 603: The source RN sends a handover request message to the source eNB, and the source eNB forwards the handover request message to the target eNB, and the target eNB makes an admission decision, and sends a handover message carrying the decision result to the source eNB, and the source eNB will The handover message carrying the decision result is sent to the source RN.

Step 604, the same as step 309.

Step 605: The UE accesses the target eNB according to the handover command message. After the access succeeds, the UE sends a handover complete message to the target eNB. The target eNB forwards the handover complete message to the source eNB, and the source eNB initiates a path switching process to the MME. The source RN initiates a resource release process, and the source eNB and the source RN release resources occupied by the UE.

FIG. 4 is a schematic diagram of a system composition for implementing cell handover according to the present invention. As shown in FIG. 3, the system includes a source RN 401, a source eNB 402, and a target node 403.

The source RN 401 receives the measurement report reported by the UE, determines whether to perform cell handover according to the measurement report, and if the handover is performed, the source eNB 402 exchanges the message with the target node 403.

The source eNB 402 forwards the handover message between the source RN 401 and the target node 403.

The target node 403 determines whether to accept the UE, and exchanges a message with the source RN 401 through the source eNB 402.

The target node 403 may be the same entity as the source eNB 402, or may be an eNB other than the source eNB, or an RN other than the source RN.

FIG. 5 is a structural diagram of a relay device for implementing cell handover according to the present invention, where the device includes The decision module 501 and the switching module 502 are switched.

The handover decision module 501 is configured to receive a measurement report reported by the UE, determine, according to the measurement report, whether to perform cell handover, and if yes, send a handover indication to the handover module 502.

The switching module 502, after receiving the handover indication, exchanges a message with the target node through the source eNB.

It can be seen that the technical solution provided by the present invention is that the source RN performs the cell handover decision according to the measurement report, and after the decision needs to be performed, the source eNB and the target node exchange the message, and the measurement report does not need to be sent. For the eNB, the amount of data transmission is reduced, thereby improving the switching speed, and since only the radio interface for the RN to communicate with the eNB needs to be set, and the other radio interface is not required to be set for the RN, the target eNB can be switched through the source eNB. Message.

The above is only the preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. Any modifications, equivalents, improvements, etc., which are made within the spirit and principles of the present invention, should be included. It is within the scope of the invention.

Claims

Claim

A method for implementing cell handover, the method includes: the source relay device RN receives a measurement report reported by the user equipment UE, determines whether to perform cell handover according to the measurement report, and if the handover is performed, the source RN The message is exchanged by the source base station eNB and the target node.

The method according to claim 1, wherein the message exchanged by the source RN and the target node by the source eNB includes:

The source RN sends a handover request message to the source eNB, and the source eNB identifies the target node according to the handover request message, and forwards the handover request message to the target node.

The target node performs an admission decision according to the handover request message. If the UE is admitted, the source eNB sends a handover request acknowledgement message to the source RN.

The source RN sends a handover command message to the UE, and the UE accesses the target node according to the handover command message.

3. The method of claim 2, wherein

The identifying the target node is: the eNB identifies that the target cell is directly managed by the source eNB, and the target node is the source eNB,

The source RN forwards the handover request message to the target node by the source eNB: the source RN directly sends a handover request message to the source eNB,

The source eNB sends a handover request acknowledgement message to the source RN: the source eNB directly sends a handover request acknowledgement message to the source RN;

Or,

The identifying the target node is: the eNB identifies that the target cell is directly managed by an eNB other than the source eNB, and the target node is an eNB that directly manages the target cell,

The source RN forwards the handover request message to the target node through the source eNB as: source RN to source The eNB sends a handover request message, and the source eNB forwards the handover request message to the eNB that directly manages the target cell.

The source eNB sends a handover request acknowledgement message to the source RN: the eNB directly managing the target cell sends a handover request acknowledgement message to the source eNB, and the source eNB sends the handover request acknowledgement message to the source RN;

Or,

The identifying the target node is: the eNB identifies that the target cell is managed by the RN of the source eNB, and the target node is the RN that manages the target cell,

The source RN forwards the handover request message to the target node by the source eNB. The source RN sends a handover request message to the source eNB, and the source eNB forwards the handover request message to the RN that manages the target cell.

The source eNB sends a handover request acknowledgement message to the source RN: the RN that manages the target cell sends a handover request acknowledgement message to the source eNB, and the source eNB sends the handover request acknowledgement message to the source RN;

Or,

The identifying the target node is: the eNB recognizes that the target cell is managed by an RN subordinate to the target eNB other than the source eNB, and the target node is an RN that manages the target cell, and the source RN forwards the handover request message to the source eNB by using the source eNB. The target node is: the source RN sends a handover request message to the source eNB, and the source eNB forwards the handover request message to the target eNB, and the target eNB forwards the handover request message to the RN that manages the target cell, and the source eNB The source RN sends a handover request acknowledgement message to: the RN that manages the target cell sends a handover request acknowledgement message to the target eNB, and the target eNB sends a handover request acknowledgement message to the source eNB, and the source eNB sends the handover request acknowledgement message to the source RN.

The method according to claim 2, wherein after the UE accesses the target node according to the handover command message, the method further includes: The target node initiates a resource release process to the source RN by using the source eNB, and the source RN releases the resources occupied by the UE.

5. The method of claim 4, wherein

The source eNB and the target eNB exchange handover messages through each other's X2 interface.

6. The method of claim 4, wherein

The source eNB and the target eNB send a handover message to the core network through the S1 interface, and the core network forwards the handover message to the other of the source eNB and the target eNB.

7. The method of claim 2, wherein

If it is identified that the target cell is governed by an eNB other than the source eNB, the method further includes:

After accessing the eNB that is in the target cell, the UE sends a handover complete message to the eNB, and the eNB initiates a path switching process to the core network;

If it is identified that the target cell is governed by an RN subordinate to the eNB other than the source eNB, the method further includes:

After accessing the RN of the target cell, the MME sends a handover complete message to the RN, and the RN forwards the handover complete message to the eNB to which the RN belongs, and the eNB to which the RN belongs initiates a path switching process to the core network. .

8. The method according to claim 7, wherein the path switching process is initiated to the core network through the S1 interface.

9. A method as claimed in any of claims 1 to 8, characterized in that

The RN stores the context information of the UE and the neighbor relationship of each cell governed by the RN.

10. The method of any of claims 9 wherein:

The eNB stores information of all RNs connected to the eNB.

The method according to claim 10, wherein the information of the RN includes An identifier used to distinguish whether a cell is directly managed by an eNB or managed by an RN.

The method according to claim 11, wherein the identifier is a cell access mode, and if the cell is a radio access mode, the cell is managed by the RN, and if the cell is a wired access mode, Then the cell is directly managed by the eNB.

13. The method of claim 2, wherein

The handover request message carries the identifier ID of the target RN, the bearer information of the UE in the source RN, the RRC context, the handover area restriction information, and the UE history information.

A system for implementing cell handover, the system comprising: a source RN, receiving a measurement report reported by a UE, determining, according to the measurement report, whether to perform cell handover, and if performing handover, interacting with the target node by using the source eNB Switching the message; the source eNB, forwarding the handover message between the source RN and the target node;

15. The system of claim 14 wherein:

The target node is the source eNB, or an eNB other than the source eNB, or a target RN other than the source RN.

A relay device for implementing cell handover, characterized in that the device comprises a handover decision module and a handover module;

The handover decision module is configured to receive a measurement report reported by the UE, determine, according to the measurement report, whether to perform cell handover, and if yes, send a handover indication to the handover module; the handover module, after receiving the handover indication, passes the source eNB Interact with the target node to switch messages.