WO2012106985A1

WO2012106985A1 - Relay node handover method and system

Info

Publication number: WO2012106985A1
Application number: PCT/CN2012/070760
Authority: WO
Inventors: 游世林; 卢飞; 梁爽
Original assignee: 中兴通讯股份有限公司
Priority date: 2011-02-11
Filing date: 2012-01-30
Publication date: 2012-08-16
Also published as: CN102638860A

Abstract

Disclosed is a relay node (RN) handover method, comprising the following steps: after receiving a handover instruction message sent from a source mobility management entity (MME) accessed by an RN, a donor evolved NodeB (DeNB) selects a target MME capable of supporting access of the RN, and carries the address of the target MME to initiate a handover request to the source MME accessed by the RN, and the source MME hands over the RN to the target MME selected by the DeNB; or the DeNB initiates a handover request to the source MME, the source MME selects a target MME supporting access of the RN and hands over the RN to the selected target MME. Also disclosed is an RN handover system. According to the present invention, the RN can be handed over to other MME supporting access of the RN when the MME accessed by the RN is overloaded, thereby preventing service interruption of the terminal connected to the network by using the RN and improving user experience.

Description

Relay node switching method and system

The present invention relates to the field of communications technologies, and in particular, to a relay node (RN) switching method and system. Background technique

In order to maintain the competitiveness of the third generation mobile communication system in the field of communication, the 3GPP (3rd Generation Partnership Project) standard working group is working on the research of EPS (Evolved Packet System). FIG. 1 is a schematic structural diagram of an EPS system in the related art. As shown in FIG. 1 , the EPS system mainly includes an E-UTRAN (Evolved Universal Terrestrial Radio Access Network) and an EPC (Evolved Packet Core). The packet core network) two parts. The EPC of the system can support users' access from GERAN (GSM EDGE radio access network, GSM EDGE radio access network) and UTRAN (Universal Terrestrial Radio Access Network).

In the EPC packet core network, the HSS (Home Subscriber Server), the MME (Mobility Management Entity), the S-GW (Serving Gateway), and the P-GW (PDN Gateway) are included. , Packet Data Network Gateway), SGSN (Serving GPRS Support Node), and PCRF (Policy and Charging Enforcement Function), where:

HSS is the permanent storage location of user subscription data, located in the home network that the user subscribes to; MME, is the location where the user subscription data is stored in the current network, and is responsible for the NAS-to-network (Non-Access Stratum, non-access layer) letter. Let management, user tracking in idle mode And paging management functions and bearer management;

The S-GW is a gateway from the core network to the wireless system, and is responsible for the user plane of the terminal to the core network, the data buffer in the terminal idle mode, the function of initiating a service request by the network side, the legal eavesdropping, and the packet data routing and forwarding function;

P-GW is an evolved packet domain system (EPS) and a gateway of the external network of the system, and is responsible for functions such as IP address allocation, charging function, packet filtering, and policy application of the terminal;

The SGSN is a service support point for GERAN and UTRAN users to access the EPC network. It functions similarly to the MME and is responsible for user location update, paging management, and bearer management.

The PCRF is responsible for providing policy control and charging rules to the PCEF.

In some scenarios, the concept of a relay node has been introduced in order to expand wireless coverage or temporarily increase the ability of wireless to provide access to users. 2 is a schematic diagram of a network architecture after the introduction of a relay in the related art, as shown in FIG. 2, in the network architecture,

RN, contains two parts of functions, UE and relay node. The RN-side acts as a UE accessing the network, establishes a bearer and other related operations, and on the other hand, provides an access for the UE as an eNB;

The DeNB ( Donor eNodeB, donor base station) provides radio access for the RN, terminates the RRC signaling of the RN-UE, and terminates the S1AP signaling and the X2 signaling of the RN-eNB. Simultaneously setting the SGW and PGW of the RN-UE;

RN OAM (Relay Node Operator and Management), from which the RN obtains the necessary connection information.

When the RN is a UE, the MME and the eNB that provide services for the RN-UE need to have corresponding enhancement functions. Therefore, it is necessary to ensure that the RN can select the enhanced eNB and the MME.

The terminal can access the network through the RN, and the DeNB selects the MME for the terminal, and the UE-MME can be an enhanced MME or an ordinary MME. Due to the introduction of the RN function, the MME function is enhanced. Therefore, when establishing a connection for the RN, the DeNB needs to select an MME supporting the RN function for the RN. The MME in the network may be overloaded for a period of time due to the number of terminals accessed and the number of services established by the terminal. The MME may choose to uninstall certain terminals. On the other hand, due to operational reasons, some MMEs need to be removed from the network, and the UEs on these MMEs also need to be uninstalled. In the prior art, the process for the MME to uninstall the UE is as shown in FIG. 3, and the process includes:

Step 301: The MME selects some or all UEs to perform offloading. For the UE that needs to be offloaded, the MME sends a UE context release command to the eNB, where the reason is carried, indicating that the reason for the release is offloading.

Step 302: The eNB initiates release of the radio air interface resource (RRC), where the reason is carried, and the reason for the release is offload.

Step 303: The eNB returns a UE context release complete message to the MME.

Step 304: The UE initiates an RRC connection request and a TAU request, where the RRC connection request does not include the registered MME identification information.

Step 305: The eNB selects an un-loaded MME for the UE according to the request of the UE.

Step 306: Complete the remaining process of the TAU.

In addition, in the prior art, when the MME is overloaded, the MME will send an Overload Start message to all eNBs connected thereto, and the eNB rejects the UE access corresponding to the access according to the overload information. After the MME is released, the MME sends an eNB Overload Stop message, and the eNB ends the overload operation according to the message. The overload start command and the overload end command are independent messages between devices.

However, when the MME of the RN is overloaded, the resources of the RN may be released, and the release of the RN resources may cause the terminal service interruption connected to the network through the RN to affect the user experience. Summary of the invention

In view of this, the main object of the present invention is to provide a relay node switching method and system, It can avoid the interruption of terminal services connected to the network through the RN and improve the user experience.

In order to achieve the above object, the technical solution of the present invention is achieved as follows:

A relay node RN switching method includes:

After receiving the handover indication message sent by the source mobility management entity MME accessed by the RN, the donor base station DeNB selects the target MME that supports the RN access, and carries the target MME address to initiate a handover request to the source MME accessed by the RN. The source MME switches the RN under it to the target MME selected by the DeNB,

Or, after receiving the handover indication message sent by the source MME accessed by the RN, the DeNB initiates a handover request to the source MME, and the source MME selects a target MME that supports the RN access, and switches the RN under the MME to the MME. The selected target MME.

The handover indication message is an overload start command that carries source MME information.

The source MME switches the RN under it to the target MME as: The source MME switches the part of the RN or all of the RNs to the target MME.

The handover indication message is a context message for releasing the RN.

The source MME switches the RN under it to the target MME as: The source MME switches the RN indicated in the context message of the release RN to the target MME.

The source MME selects the target MME that supports the RN access: the source MME selects the target MME that supports the RN access according to the local configuration and/or the result of the DNS query to the domain name resolution system.

The source MME queries the DNS as: The source MME queries according to the DeNB information and the RN capability indication information, or according to the location area tracking area and the RN capability indication information, and the query result returned by the DNS carries the MME information supporting the RN access.

The source MME queries the DNS as follows: The source MME performs the MME information supporting the RN access and the MME information not supporting the RN access, and the source MME according to the capability of switching the RN according to the DeNB information or the location area tracking area query. The MME is selected to support RN access. The method further includes: starting, by the source MME, a context message that releases the RN, and then starting a timer, where the RN that needs to be handed over directly clears the UE context corresponding to the source MME.

The method further includes: the RN passing the indication or the handover command from the DeNB

The DeNB initiates an attach or tracking area update procedure to the target MME.

A relay node switching system, comprising: a DeNB, a target MME, and a source MME; wherein, the DeNB is configured to select a target MME that supports RN access after receiving a handover indication message sent by a source MME accessed by the RN And carrying the target MME address to initiate a handover request to the source MME accessed by the RN;

The source MME is configured to switch the RN under the eNB to the target MME selected by the DeNB according to the handover request sent by the DeNB.

The source MME is further configured to start a timer after the context message of the release RN is sent, and to clear the UE context corresponding to the RN that needs to be handed over at the source MME.

A relay node switching system, comprising: a DeNB, a target MME, and a source MME; wherein, the DeNB is configured to initiate a handover request to the source MME after receiving a handover indication message sent by a source MME accessed by the RN ;

And the source MME is configured to select a target MME that supports the RN access according to the handover request sent by the DeNB, and switch the RN under the RN to the selected target MME.

The source MME queries the DNS as: the source MME queries the eNB according to the DeNB information and the RN capability indication information, or according to the location area tracking area and the RN capability indication information, and the query result returned by the DNS carries the MME information that supports the RN access.

The source MME queries the DNS as: The source MME is according to the DeNB information or the location area. The query result returned by the DNS carries the MME information supporting the RN access and the MME information that does not support the RN access. The source MME selects the MME that supports the RN access according to the capability identifier of the handover RN.

The relay node switching method and system of the present invention, when the MME accessed by the RN is overloaded, selects an MME that is not overloaded and supports RN access, and switches the RN under the overloaded MME to the selected MME. The present invention can switch the RN to another MME that supports the access of the RN in the event that the MME accessing the RN is overloaded, thereby avoiding interruption of the terminal service connected to the network through the RN, thereby improving the user experience. DRAWINGS

1 is a schematic structural diagram of a system of an EPS in a related art;

2 is a schematic diagram of a network architecture after the introduction of Relay in the related art;

3 is a flowchart of an MME offloading a UE in the prior art;

4 is a flowchart of a relay node handover according to Embodiment 1 of the present invention;

FIG. 5 is a flowchart of handover of a relay node according to Embodiment 2 of the present invention. detailed description

The basic idea of the present invention is: When the MME accessed by the RN is overloaded, an MME that is not overloaded and supports RN access is selected, and the RN under the overloaded MME is switched to the selected MME.

Specifically, after receiving the handover indication message (such as the overload start command or the context message of the release RN) sent by the source MME, the DeNB selects a target MME that supports the RN access, and carries the target MME address to initiate a handover request to the source MME. , by the source MME The RN switches to the target MME selected by the DeNB, or the DeNB initiates a handover request to the source MME after receiving the handover indication message (such as the overload start command or the RN release context message) sent by the source MME, and the source MME selects The target MME supporting the RN access, and the RN under it is switched to the selected MME.

In other words, the method proposed by the present invention mainly includes:

Method 1: After the DeNB receives the overload start command or releases the context message of the RN, the DeNB selects an MME that supports the RN access, and carries the MME address to initiate a handover request to the MME accessed by the RN, and the RN accesses the MME to the RN. Switch to the MME selected by the DeNB.

Method 2: After the DeNB receives the overload start command or releases the context message of the RN, the DeNB initiates a handover request to the MME accessed by the RN, and the RN accesses the MME according to the local configuration and/or DNS (Domain Name System) The MME supporting the RN access is selected, and the RN is switched to the selected MME.

Here, the DNS discovery is selected according to the DeNB address, or the RN access MME configures an MME that supports other RN access.

It should be noted that, when the handover indication message is an overload start command carrying source MME information, the source MME switches the RN under it to the target MME: the source MME switches the part of the RN or all of the RNs to the target MME; When the handover indication message is a context message for releasing the RN, the source MME switches the RN under it to the target MME: the source MME switches the RN indicated in the context message of the release RN to the target MME.

It should be noted that the source MME may query the DNS: the source MME may perform the query according to the DeNB information and the RN capability indication information, or according to the location area tracking area and the RN capability indication information, and the query result returned by the DNS carries the MME supporting the RN access. The source MME may also query the DNS: The source MME queries the DeNB information or the location area tracking area, and the query result returned by the DNS carries the MME information supporting the RN access and the MME not supporting the RN access. Information, the source MME selects an MME that supports RN access according to the capability identifier of the handover RN.

The present invention also proposes a relay node switching system, which includes: a DeNB, a target MME, and a source MME;

And the DeNB is configured to: after receiving the handover indication message sent by the source MME that is accessed by the RN, select a target MME that supports the RN access, and carry the target MME address to initiate a handover request to the source MME that is accessed by the RN;

The DeNB is configured to initiate a handover request to the source MME after receiving the handover indication message sent by the source MME accessed by the RN;

The source MME queries the DNS as: The source MME queries the DeNB information or the location area tracking area, and the query result returned by the DNS carries the MME list information. The source MME selects an MME that supports RN access according to the capability indication of the RN. The MME list includes a supporting RN The MME that is accessed and the MME that does not support RN access.

The present invention will be further described in detail below in conjunction with specific embodiments.

Example 1

FIG. 4 is a flowchart of switching a relay node according to Embodiment 1 of the present invention. As shown in FIG. 4, the process includes:

Step 401: The MME1 is overloaded, and sends an overload start command to the DeNB. Alternatively, the MME1 determines to uninstall the RN, and sends a UE context release command to the DeNB, where the reason is carried, the reason for the release is offload, and the MME1 sets a corresponding release UE context timer. Tl.

Step 402: The DeNB sends a measurement request to the RN, and the RN sends a measurement report to the DeNB. It should be noted that the DeNB may cancel the process according to actual conditions.

Step 403: The DeNB selects an MME that supports RN access according to the information saved in the S1 setup message, and the MME2 is a working MME, and no overload occurs. The DeNB carries the MME2 address, and sends a handover request message to the MME1. The message also carries the DeNB identity of the handover target eNB.

Step 404: After receiving the handover request message, the MME1 resets or stops releasing the UE context timer T1, and sends a forwarding handover request message to the MME2 according to the MME2 address carried in the message, where the message carries the DeNB of the handover target eNB. Logo.

Step 405: The MME2 sends a handover request message to the DeNB according to the DeNB identifier of the handover target eNB, and the DeNB sends a handover request response message to the MME2.

Step 406: The MME2 sends a handover forwarding request response message to the MME1.

Step 407: The MME1 sends a handover command message to the DeNB.

Step 408: The DeNB sends a handover command message to the RN. In the handover command, the DeNB may also instruct the RN to initiate an attach or tracking area update procedure. Step 409: The RN sends a handover confirm message to the DeNB.

It should be noted that, 409 is an optional step, and the DeNB may not send the step 409 message. Step 410: After receiving the handover confirmation message in step 510, the DeNB sends a handover notification message directly to the MME2.

Step 411: The MME2 sends a Forward Handover Complete Notification message to the MME1, and the MME1 sends back a corresponding response message to the MME2.

Step 412: The MME2 sends a modify bearer request message to the DeNB, and the DeNB sends back a modification request message to the MME2.

Step 413: The DeNB sends a UE context release complete message to the MME1. If the T1 timer is timed out, or the UE context corresponding to the RN in the MME1 has not been cleared by the handover procedure, the MME1 clears the UE context corresponding to the RN.

Step 414: The RN initiates an attach or tracking area update procedure to the MME2 through the DeNB according to the indication described in step 408 or after the RN receives the handover command, and the MME2 saves the user data of the RN.

Example 2

FIG. 5 is a flowchart of switching a relay node according to Embodiment 2 of the present invention. As shown in FIG. 5, the process includes:

Step 501: MME1 is overloaded, and sends an overload start command to the DeNB. Alternatively, it is determined to uninstall the RN, and sends a UE context release command to the DeNB, where the reason is carried, the reason for the release is offload, and the MME1 sets the corresponding release UE context timer T1. .

Step 502: The DeNB sends a measurement request to the RN, and the RN sends a measurement report to the DeNB. The DeNB can cancel the process according to actual conditions.

Step 503: The DeNB sends a handover request message to the MME1, where the message further carries the DeNB identifier of the handover target eNB. Step 504: After receiving the handover request, the MME1 resets or stops releasing the UE context timer T1, and finds that it is an RN handover according to the identity of the target eNB and the source target DeNB identity, or the identity of the RN itself, and the MME1 Select one to support RN access to MME2.

The MME1 selects the MME2 to be configured according to the local configuration of the MME1, that is, the MME1 supports the corresponding RN to access the MME address, or the MME1 carries the DeNB identifier to send a DNS discovery request to the DNS server, and the DNS server according to the DeNB identifier and the RN capability indication identifier, or And selecting an MME supporting the RN access according to the tracking area information and the RN capability indication identifier, and carrying the corresponding identifier, and returning a DNS discovery request response message to the MME1. Or the DNS server selects the corresponding MME list under the DeNB and returns it to the MME1 according to the DeNB identity or the tracking area information. The MME1 selects the MME that supports the RN access in the MME list according to the capability indication of the RN. The MME list includes an MME that supports RN access, and an MME that does not support RN access.

Step 505: The MME1 sends a Forward Handover Request message to the selected MME2, where the message carries the DeNB identity of the handover target eNB.

Step 506: The MME2 sends a handover request message to the DeNB according to the DeNB identifier of the handover target eNB, and the DeNB sends a handover request response message to the MME2.

Step 507: The MME2 sends a handover forwarding request response message to the MME1.

Step 508: The MME1 sends a handover command message to the DeNB.

Step 509: The DeNB sends a handover command message to the RN.

In the handover command, the DeNB may also instruct the RN to initiate an attach or tracking area update procedure. Step 510: The RN sends a handover confirmation message to the DeNB.

It should be noted that, 510 is optional, and the DeNB may not send the step 510 message.

Step 511: After receiving the handover confirmation message in step 510, the DeNB sends a handover notification message directly to the MME2.

Step 512: MME2 sends a forwarding handover completion notification message to MME1, and MME1 sends The MME2 sends back a corresponding response message.

Step 513: The MME2 sends a modify bearer request message to the DeNB, and the DeNB sends a modification request message to the MME2.

Step 514: The DeNB sends a UE context release complete message to the MME1. If the T1 timer is timed out, or the UE context corresponding to the RN in the MME1 has not been cleared by the handover procedure, the MME1 clears the UE context corresponding to the RN.

Step 515: The RN initiates an attach or tracking area update procedure to the MME2 through the DeNB according to the indication described in step 509 or after the RN receives the handover command, and the MME2 saves the user data of the RN. The above two embodiments only switch the MME1 with the RN access overload to the MME2 that is not overloaded by the supporting RN, which not only ensures the normal operation of the RN, but also ensures the service continuity of the user accessing the RN.

The above is only the preferred embodiment of the present invention and is not intended to limit the scope of the present invention.

Claims

Claim

A relay node RN switching method, where the method includes:

2. The method according to claim 1, wherein the handover indication message is an overload start command carrying source MME information.

3. The method according to claim 1, wherein the handover indication message is a context message for releasing the RN.

The method according to any one of claims 1 to 3, wherein the source MME selects a target MME that supports RN access: the source MME selects according to a local configuration and/or a result of a DNS query to the domain name resolution system. The target MME supporting RN access.

The method according to claim 4, wherein the source MME queries the DNS as: the source MME queries according to the DeNB information and the RN capability indication information, or according to the location area tracking area and the RN capability indication information, and the DNS returns the query. The result carries the MME information supporting the RN access.

6. The method according to claim 4, wherein the source MME queries the DNS as: The source MME searches for the MME information that supports the RN access and the MME information that does not support the RN access, and the source MME selects the RN to support the RN according to the capability identifier of the handover RN. MME.

The method according to claim 3, wherein the method further comprises: after the source MME sends a context message for releasing the RN, starting a timer, where the RN that needs to be handed over when the timer expires is still in the UE context corresponding to the source MME. If not cleared, the UE context corresponding to the RN that needs to be handed over at the source MME is directly cleared.

The method according to claim 1, wherein the method further comprises: the RN initiating an attach or tracking area update procedure to the target MME by the DeNB according to an indication or a handover command from the DeNB.

A relay node switching system, where the system includes: a DeNB, a target MME, and a source MME;

10. The system according to claim 9, wherein

The DeNB is configured to initiate a handover request to the source MME after receiving a handover indication message sent by the source MME accessed by the RN; The source MME is configured to select a target MME supporting the RN access according to the handover request sent by the DeNB, and switch the RN under the handover to the selected target MME.

The system according to claim 11, wherein the source MME selects a target MME that supports RN access: the source MME selects a RN to support according to a local configuration and/or a result of a DNS query to the domain name resolution system. Target MME.

The system according to claim 12, wherein the source MME queries the DNS as: the source MME queries according to the DeNB information and the RN capability indication information, or according to the location area tracking area and the RN capability indication information, and the DNS returns the query. The result carries the MME information supporting the RN access.

The system of claim 12, wherein the source MME queries the DNS as: the source MME queries according to the DeNB information or the location area tracking area, and the query result returned by the DNS carries the MME information supporting the RN access and does not The MME that supports the RN access, the source MME selects the MME that supports the RN access according to the capability identifier of the handover RN.

15. The system of claim 11 wherein