CN102378208A

CN102378208A - Processing method for VLR fault and system thereof

Info

Publication number: CN102378208A
Application number: CN2010102540383A
Authority: CN
Inventors: 朱进国; 强宇红; 梁爽
Original assignee: ZTE Corp
Current assignee: ZTE Corp
Priority date: 2010-08-11
Filing date: 2010-08-11
Publication date: 2012-03-14

Abstract

The invention discloses a processing method for a fault of a visitor location register (VLR). According to the method, after a mobile management unit detects that an SGs / Gs interface is broken, a VLR is reselected and an SGs / Gs link is established between the VLR and mobile management unit; and then a temporary mobile subscriber identity (TMSI) and a location area identifier (LAI) as well as a temporary subscriber identity and a location identifier are sent to a corresponded user equipment (UE), wherein the TMSI and the LAI are distributed by the VLR and the temporary subscriber identity and the location identifier are distributed by the mobile management unit. Correspondedly, the invention also discloses a processing system for a VLR fault. According to the invention, when a VLR in an MSC/VLR pool is failed, correlated UE is migrated to other VLRs, so that the UE can be recovered to a state in which a voice call can be initiated and received as soon as possible.

Description

VLR fault processing method and system

Technical Field

The present invention relates to the field of mobile communications, and in particular, to a method and a system for processing a Visitor Location Register (VLR) fault.

Background

Fig. 1 is a schematic diagram of an Architecture of Packet Switched Core (PS Core) Evolution defined by the third Generation Partnership Project (3 GPP), as shown in fig. 1, the Network System includes a User Equipment (UE), a Radio Network Controller (RNC), a VLR, a mobility management unit, an evolved Radio node b (eNodeB), and an SAE gateway (System Architecture Evolution GW, SAE GW); wherein,

the UE has the capability of accessing two wireless networks, namely, a Universal mobile telecommunications System Radio Access Network (UTRAN) and a Long Term Evolution air interface (LTE).

The evolved wireless node may provide higher uplink and downlink rates, lower transmission delays, and more reliable wireless transmissions than UTRAN. The eNodeB provides radio resources for access of the terminal while establishing S1 a control plane link with the core network MME.

The Mobility Management Entity (MME) is a control plane Entity, a server for temporarily storing user data, and is responsible for managing and storing UE contexts, such as a UE id, a Mobility Management state, and a user security parameter, and allocating a temporary identity guti (global uniform temporal identity) to a user, where when the UE is camped in the tracking area or the network is responsible for authenticating the user. In UMTS, the mobility management entity is called a Serving GPRS Support Node (SGSN), and the SGSN allocates a temporary identity P-TMSI to the user.

The SAE GW is a user plane entity responsible for user plane data routing processing. The SAE GW is generally divided into a Serving gateway Serving GW and a packet data network gateway PDN GW, the Serving GW is responsible for an anchor point of mobility between LTE and UMTS, and downlink data triggers MME and SGSN paging in an idle state; the PDNGW is responsible for a gateway function of the UE accessing a Packet Data Network (PDN), and allocates a user ip (internet protocol) address to the user. The PDN GW and Serving GW may be collocated in one physical entity.

In a conventional circuit domain switching architecture, a core network element includes an MSC and a Visitor Location Register (VLR), and the MSC and the VLR are physically combined together. The VLR assigns a temporary identity (TMSI) to the user.

The radio network controller functions similar to the eNodeB in the evolved architecture, and is responsible for establishing an Iu interface connection with the UE and the core network.

The evolved architecture is packet domain, and when the packet domain itself does not support voip (voice Over ip), if the UE resides under the packet domain LTE at this time, the problem of voice call must be solved. One solution is called csfb (cs fallback), in which the voice call is still carried in the circuit domain, and when a call needs to be initiated, the packet domain needs to fallback the UE to the circuit domain. As in the architecture of fig. 1, there is an interface between the circuit domain VLR and the MME of the packet domain, called SGs interface (if the packet domain is SGSN, the interface is called Gs interface). The main function of the Gs/SGs interface is that when UE is jointly registered in the packet domain mobility management entity, the mobility management entity initiates registration to the circuit domain VLR at the same time, so that the UE is simultaneously registered in the circuit domain and the packet domain. When the UE initiates a voice call, the UE is firstly accessed from the packet domain and then retreats to the circuit domain, and because the UE is registered in the circuit domain, the success of call initiation is ensured; when a called party to the UE reaches the VLR, the VLR knows that the UE is currently in the packet domain, so that the UE is paged from the SGs/Gs interface, the mobile management entity further pages the UE in the packet domain, the UE responds to and accesses the paging in the packet domain and then returns to the circuit domain, and the success of the final call is ensured.

Fig. 2 is a schematic flow diagram of establishing an SGs interface between an MME and a VLR in the prior art, and as shown in fig. 2, the establishing process of the SGs interface includes:

step 201: after the MME determines to establish the SGs interface, a suitable Location Area Identifier (LAI) is found according to a Tracking Area Identifier (TAI) registered by the user, and then a suitable VLR is found. MME sends a location update request to VLR, wherein the location update request contains the obtained LAI and IMSI information of the user.

Step 202: after receiving the Location update request from the MME, the VLR completes a registration procedure of the UE in the VLR, for example, a procedure of acquiring user subscription data from a Home Location Register (HLR), and the VLR allocates a Temporary Mobile Subscriber Identity (TMSI) to the user. After the registration is completed, the VLR returns a location update response to the MME containing the LAI and TMSI of the user registration.

Fig. 3 is a schematic flow chart of a UE initiating a voice call in the existing CSFB (circuit-switched fallback) technology, and as shown in fig. 3, a circuit domain call initiation process includes:

step 301: the UE resides in the packet domain, and when the UE needs to initiate a call, a packet domain service request is initiated to the MME.

Step 302: radio bearers and S1 bearers are established among the UE, the eNodeB and the MME, and the UE enters a link state of a packet domain.

Step 303: the eNodeB instructs the UE to fall back to the circuit domain through a message.

Step 304: the UE initiates a circuit domain service request in the circuit domain, and the message is routed to the registered VLR.

Step 305: the VLR continues the subsequent call initiation processing procedure and establishes a call.

Fig. 4 is a schematic diagram illustrating a flow of a UE receiving a voice call in the existing CSFB technique, and as shown in fig. 4, a terminating procedure of a circuit domain call includes:

step 401: the VLR discovers that the UE is currently in the packet domain and then initiates a paging request to the MME through the SGs.

Step 402: the MME performs CS paging in all TAIs where the UE is registered.

Step 403: the UE returns to MME paging and initiates a packet domain service request.

Step 404: radio bearers and S1 bearers are established among the UE, the eNodeB and the MME, and the UE enters a link state of a packet domain.

Step 405: the eNodeB instructs the UE to fall back to the circuit domain through a message.

Step 406: the UE initiates a paging response and a circuit domain service request in the circuit domain, and the message is routed to the registered VLR.

Step 407: the VLR continues the subsequent terminating call processing procedure to establish the call.

In order to perform load sharing and disaster tolerance among VLRs, a technology of an MSC/VLR pool is introduced into 3GPP, as shown in fig. 1, all MSC/VLRs in one MSC/VLR pool are connected to an RNC through an Iu port. When one MSC \ VLR in the pool has a fault, the MSC \ VLR pool technology can transfer the UE in the MSC \ VLR to other MSC \ VLRs in the pool; and the MSC \ VLR in the pool also serves the UE in a load sharing mode. The MSC and VLR are typically unified.

However, in the CSFB technique, when one VLR in the MSC/VLR pool fails, the relevant UE cannot be migrated to another VLR at present, and the UE cannot initiate and receive a voice call before reestablishing SGs.

Disclosure of Invention

In view of this, the main objective of the present invention is to provide a method and a system for VLR failure, which can migrate the relevant UE to other VLRs when a VLR in an MSC/VLR pool fails, so that the UE can recover the state capable of initiating and receiving a voice call as soon as possible.

In order to achieve the purpose, the technical scheme of the invention is realized as follows:

a method for processing fault of Visitor Location Register (VLR) includes:

after detecting that the SGs/Gs interface is disconnected, the mobility management unit reselects the VLR and establishes SGs/Gs link with the VLR, and then sends the temporary identifier TMSI and the location area identifier LAI allocated by the VLR, and the temporary user identifier and the location identifier allocated by the mobility management unit to the corresponding user terminal UE.

After the mobile management unit detects that the SGs/Gs interface is disconnected, reselecting the VLR and establishing SGs/Gs link with the VLR:

after detecting that the SGs/Gs interface is disconnected, the mobile management unit immediately reselects a VLR and establishes SGs/Gs link with the reselected VLR; or,

and after detecting that the SGs/Gs interface is disconnected, the mobile management unit triggers corresponding UE to initiate a joint update request, reselects a VLR according to the joint update request and establishes SGs/Gs link with the VLR.

The said mobile management unit triggers UE to initiate a joint update request as follows:

the mobile management unit sends a GUTI re-allocation request to the UE, wherein the GUTI re-allocation request carries a TAI list which is not registered by the UE;

after receiving the GUTI reallocation request, the UE stores the TAI list as a currently registered TAI list;

and the UE monitors the radio cell broadcast, and initiates a joint update request when determining that the TAI broadcasted by the cell is not in the currently registered TAI list.

Before the mobility management unit sends TMSI and LAI allocated by the VLR, and the temporary subscriber identity and location identity allocated by the mobility management unit to the corresponding UE, under the condition that the mobility management unit immediately reselects the VLR and establishes an SGs/Gs link with the VLR after detecting that the SGs/Gs interface is disconnected, the method further comprises:

the mobile management unit judges whether the UE is in an idle state at present, if the UE is in the idle state, the UE is paged, and then TMSI and LAI distributed by VLR and temporary user identification and location identification distributed by the mobile management unit are sent to the UE; and if the UE is not in an idle state, directly sending the TMSI and the LAI distributed by the VLR and the temporary user identifier and the location identifier distributed by the mobile management unit to the UE.

Before the mobility management unit sends a GUTI re-allocation request to the UE, the method further comprises: the mobile management unit judges whether the UE is in an idle state at present, if the UE is in the idle state, the mobile management unit pages the UE and then sends a GUTI reallocation request to the UE; and if the UE is not in an idle state, directly sending a GUTI reallocation request to the UE.

The mobile management unit is a mobile management entity MME;

the temporary user identifier allocated by the mobile management unit is a temporary identifier GUTI;

the location identity allocated by the mobility management unit is a Tracking Area Identity (TAI).

The mobile management unit is a general wireless service technology service support node SGSN;

the temporary user identification allocated by the mobile management unit is P-TMSI;

the location identifier allocated by the mobility management unit is a Routing Area Identifier (RAI).

A VLR failure handling system comprising: a mobile management unit, VLR and UE; wherein,

the mobility management unit is configured to reselect a VLR and establish an SGs/Gs link with the VLR after detecting that an SGs/Gs interface is disconnected, and then send the TMSI and LAI allocated by the VLR and the temporary subscriber identity and location identity allocated by the mobility management unit to corresponding UE;

and the VLR is used for informing the VLR of allocating TMSI and LAI for the UE in the process of establishing SGs/Gs link with the VLR.

The mobility management unit is further configured to determine whether the UE is currently in an idle state before sending the TMSI and LAI allocated by the VLR, and the temporary user identity and location identity allocated by the mobility management unit to the corresponding UE, and send the TMSI and LAI allocated by the VLR, and the temporary user identity and location identity allocated by the mobility management unit to the UE after paging the UE if the UE is in the idle state; and if the UE is not in an idle state, directly sending the TMSI and the LAI distributed by the VLR and the temporary user identifier and the location identifier distributed by the mobile management unit to the UE.

The mobile management unit is also used for judging whether the UE is in an idle state before sending a GUTI reallocation request to the UE, and if the UE is in the idle state, the mobile management unit pages the UE and then sends the GUTI reallocation request to the UE; and if the UE is not in an idle state, directly sending a GUTI reallocation request to the UE.

The mobile management unit is an MME;

the temporary user identification allocated by the mobile management unit is GUTI;

the location identity assigned by the mobility management unit is a TAI.

The mobile management unit is SGSN;

the location identity assigned by the mobility management unit is RAI.

The invention relates to a VLR fault processing method and a system, wherein a mobile management unit reselects a VLR and establishes SGs/Gs link with the VLR after detecting that an SGs/Gs interface is disconnected, and then sends TMSI and LAI distributed by the VLR and temporary user identification and location identification distributed by the mobile management unit to UE, so that the related UE can be transferred to other VLRs when one VLR in an MSC/VLR pool fails, thereby enabling the UE to recover the state capable of initiating and receiving voice call as soon as possible.

Drawings

FIG. 1 is a schematic diagram of an evolved architecture of a 3 GPP-defined packet-switched core network;

fig. 2 is a schematic flow chart of establishing an SGs interface between an MME and a VLR in the prior art;

fig. 3 is a flowchart illustrating a UE initiating a voice call in the CSFB technique in the prior art;

fig. 4 is a flow chart illustrating a UE receiving a voice call in the CSFB technique of the prior art;

fig. 5 is a schematic flow chart of a VLR failure processing method according to embodiment 1 of the present invention;

fig. 6 is a flow chart of a method for processing VLR failure in embodiment 2 of the present invention.

Detailed Description

The basic idea of the invention is: after detecting that the SGs/Gs interface is disconnected, the mobile management unit reselects the VLR and establishes SGs/Gs link with the VLR, and then sends the TMSI and LAI distributed by the VLR and the temporary user identifier and the location identifier distributed by the mobile management unit to UE.

It should be noted that the mobility management unit may reselect the VLR and establish an SGs/Gs link with the reselected VLR immediately after detecting that the SGs/Gs interface is disconnected, or may trigger the UE to initiate a joint update request, and reselect the VLR according to the joint update request and establish an SGs/Gs link with the reselected VLR.

One embodiment of the mobility management unit triggering the UE to initiate the joint update request is as follows: the mobile management unit sends a temporary identity GUTI reallocation request to the UE, wherein the GUTI reallocation request carries a TAI list which is not registered by the UE. And after receiving the GUTI reallocation request, the UE stores the TAI list, considers that the UE is registered in the TAI list, and judges to initiate a joint update request when the UE finds that the TAI broadcasted by the cell is not in the currently registered TAI list by monitoring the radio cell broadcast.

It should be noted that the mobility management unit may be a Mobility Management Entity (MME) or a serving general radio service technology support node (SGSN), and accordingly, a temporary user identifier allocated by the MME is a temporary identifier (GUTI), and a location identifier allocated by the MME is a Tracking Area Identifier (TAI); the temporary user identification allocated by the SGSN is P-TMSI, and the position identification allocated by the SGSN is Routing Area Identification (RAI).

The invention also provides a system for processing the VLR fault, which comprises: a mobile management unit, VLR and UE; wherein,

The mobile management unit is an MME;

the location identity assigned by the mobility management unit is a TAI.

The mobile management unit is SGSN;

the location identity assigned by the mobility management unit is RAI.

The technical solution of the present invention is further described in detail with reference to the following examples.

Example 1

And when the MME detects that the SGs interface is disconnected, informing the UE through a temporary identifier GUTI reallocation mechanism, wherein the temporary identifier GUTI reallocation mechanism is provided with the unregistered TAI list, triggering the terminal to initiate a joint update request, reselecting an available VLR in the pool by the MME, and reestablishing the SGs link.

Fig. 5 is a schematic flow chart of a method for processing VLR failure in embodiment 1 of the present invention, as shown in fig. 5, the method includes the following steps:

step 501: the MME and VLR1 first establish the SGs interface.

Step 502: the MME detects VLR1 failure, i.e. the SGs interface of VLR1 is disconnected.

The SGs interface employs Stream Control Transmission Protocol (SCTP), which is a Protocol with a link, so that when SCTP finds that the other party is unavailable, a notification message is initiated to an SGs application Protocol (SGsAP) of an upper layer, so that the MME can detect that VLR1 has failed.

Step 503: and if the UE is in an idle state currently, initiating paging in all TA registered by the UE.

Here, if the UE is not currently in the idle state, this step and step 504 are skipped.

Step 504: and the UE returns the paging response, establishes the connection between the UE and the MME and enters a connection state.

In a specific implementation, the link between the UE, eNodeB, MME and SAE GW is established at the same time. And the UE enters a connection state and can transmit uplink and downlink data.

Step 505: MME initiates GUTI reallocation request to UE.

The TAI carried in the GUTI re-allocation request is a new TAI that the UE is not currently registered, for example, the TAC in the TAI list may be set to full F.

Step 506: and after receiving the GUTI reallocation request, the UE returns a GUTI reallocation response, stores a new TAI which is not registered currently by the UE, and considers that the UE is registered currently in the TAI list.

Step 507: the UE monitors the radio cell broadcast, finds that the TAI broadcasted by the cell is not in the currently registered TAI list, and then judges that the joint TA/LA update needs to be initiated.

Step 508: and the UE initiates a combined TA/LA updating request carrying the TAI of the current cell.

Step 509: after the MME receives the combined TA/LA updating request, a proper LAI is found according to the TAI of the current cell, another available new VLR2 is found, and an SGs interface between the MME and the VLR2 is established.

In this process, VLR2 returns the registered LAIs and TMSI, a process that is prior art and not described in detail herein.

Step 510: and the MME returns a UE combined TA/LA updating response, carries the GUTI and TAI lists distributed by the MME and the TMSI and LAI distributed by the VLR2, and finishes the updating process.

Through the above process, the UE performs circuit domain registration again in the new VLR2, the MME establishes SGs link with the new VLR2, and the new VLR2 can handle the origination and termination of the UE voice call.

Example 2

In this embodiment, when the MME detects that the SGs interface is disconnected, the MME reselects an available VLR in the MSC/VLR pool first, and reestablishes an SGs link; and then, the MME brings the TMSI and the LAI allocated by the new VLR and the GUTI and the TAI allocated by the MME to the UE through a temporary identity GUTI reallocation process.

Fig. 6 is a schematic flow chart of a method for processing VLR failure in embodiment 2 of the present invention, as shown in fig. 6, the method includes the following steps:

step 601: the MME and VLR1 first establish the SGs interface.

Step 602: the MME detects VLR1 failure.

Because the SGs interface employs SCTP, when SCTP finds that the opposite party is unavailable, it initiates a notification message to the SGsAP of the upper layer, so that the MME can detect the VLR1 failure.

Step 603: the MME first selects an available VLR2 in the MSC/VLR pool, then initiates a location update to VLR2, establishes an SGs interface to VLR2, and VLR2 returns to the MME the new TMSI and LAI for UE registration.

Step 604: and when the UE is in an idle state currently, the MME initiates paging in all TA lists registered by the UE.

Here, if the UE is not in the idle state, the present step and step 605 are omitted.

Step 605: and the UE returns a paging response, establishes a link between the UE and the MME and enters a connection state.

In practical application, the step establishes links among the UE, the eNodeB, the MME and the SAE GW at the same time. After the UE enters the connected state, uplink and downlink data may be transmitted.

Step 606: MME initiates GUTI reallocation request to UE.

The GUTI reallocation request carries new GUTI and TAI lists allocated by the MME, and simultaneously carries LAI and TMSI allocated by the VLR 2.

Step 607: after the UE receives the GUTI reallocation, the GUTI, the TAI list, the LAI and the TMSI are saved, and a GUTI reallocation response is returned.

It should be noted that, in both the above two embodiments, an evolved packet domain is taken as an example, and these methods are also applicable to a 3G packet domain, where the MME is modified to SGSN, the SGs interface is modified to Gs, the GUTI is modified to P-TMSI, and the TAI is modified to Routing Area Identity (RAI).

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

Claims

1. A method for processing fault of Visitor Location Register (VLR), the method includes:

2. The method according to claim 1, wherein the reselecting VLR and establishing SGs/Gs link with the VLR after the mobility management unit detects that the SGs/Gs interface is disconnected are:

3. The method of claim 2, wherein the triggering of the UE to initiate the joint update request by the mobility management unit is:

4. The method according to claim 2, wherein in the case that the mobility management unit reselects VLR and establishes SGs/Gs link with the VLR immediately after detecting that the SGs/Gs interface is disconnected, before the mobility management unit sends TMSI and LAI allocated by VLR and the temporary subscriber identity and location identity allocated by the mobility management unit to the corresponding UE, the method further comprises:

5. The method of claim 3, wherein before the mobility management unit sends the GUTI reallocation request to the UE, the method further comprises: the mobile management unit judges whether the UE is in an idle state at present, if the UE is in the idle state, the mobile management unit pages the UE and then sends a GUTI reallocation request to the UE; and if the UE is not in an idle state, directly sending a GUTI reallocation request to the UE.

6. The method according to any one of claims 1 to 5,

the mobile management unit is a mobile management entity MME;

7. The method according to any one of claims 1 to 5,

8. A system for handling VLR failures, comprising: a mobile management unit, VLR and UE; wherein,

9. The system of claim 8, wherein the reselecting VLR and establishing SGs/Gs link with the VLR after the mobility management unit detects that the SGs/Gs interface is disconnected are:

10. The system of claim 9, wherein the mobility management unit triggers the UE to initiate the joint update request by:

11. The system of claim 9,

12. The system of claim 10,

13. The system according to any one of claims 8 to 12,

the mobile management unit is an MME;

the location identity assigned by the mobility management unit is a TAI.

14. The system according to any one of claims 8 to 12,

the mobile management unit is SGSN;

the location identity assigned by the mobility management unit is RAI.