WO2007112683A1

WO2007112683A1 - Method,apparatus and system for call recovery

Info

Publication number: WO2007112683A1
Application number: PCT/CN2007/001041
Authority: WO
Inventors: Jun Fang; Sihai Ye; Guojun Zhu
Original assignee: Huawei Technologies Co. Ltd.
Priority date: 2006-04-05
Filing date: 2007-03-30
Publication date: 2007-10-11
Also published as: CN100455133C; CN1968504A

Abstract

A method,device and system for call recovery when network is faulty are provided. The method includes: Notifying the user belonged to the faulty msc to update location; After location updated, a new well-msc is allocated to the user and call is resumed. The apparatus includes: control unit and call recovery unit. The system includes: control unit and msc. In the invention, when msc or path which connects access network and msc is faulty, the user belonged to the faulty msc is notified to update location and a new well-msc is allocated to the user in order to resume latter call of the user. Then shorten the call delay and the time of call recovery.

Description

Call recovery method, device and system

This application claims priority to Chinese Patent Application No. 200610072613.1, entitled "Call Recovery Method and System in the Case of Network Failure", filed on April 5, 2006, the entire contents of which are incorporated herein by reference. In the application.

Technical field

The present invention relates to the field of communications technologies, and in particular, to a call recovery method, apparatus, and system. Background technique

In the case of the traditional Global System for Mobile Communications (GSM)/Universal Mobile Telecommunications System (UMTS, Universal Mobile Telecommunications System), a Radio Network Controller (RC) or a Base Station Controller (BSC) , Base Station Controller ) can only be connected to a Mobile Switching Center (MSC). With the development of the softswitch architecture, large-capacity networks are increasingly used in wireless communication systems. Security has become an issue of increasing concern to operators. How to avoid large-scale business interruption under a single point of failure is The problems faced by equipment vendors.

R5 (3GPP R5, Third Generation Partnership) in the 3rd Generation Partnership Project

In the Projects R5 phase, Iu-Flex/A-Flex technology was proposed. In the Iu-Flex/A-Flex networking technology, an RNC or a BSC can be connected to multiple MSCs at the same time to form a resource pool. In this way, a large-area service interruption occurs in the case of a single MSC failure, and MSC load sharing and resource sharing in the pool can be realized.

Please refer to FIG. 1 , which is a schematic diagram of the Iu-Flex networking structure in the prior art. As shown in Figure 1, in one

In the Iu-Flex network, four RNCs (shown in Figures 11 - 14) are connected to three MSCs (shown as 21 - 13 in the figure). When one of the MSCs fails, the call needs to be transferred to the other. The normal MSC is performed. The recovery process of the failure is: When a certain MSC is unavailable, when the user accesses the network (location update or call request), the RNC re-assigns the user's attribution in the remaining MSCs. The time to reassign all users is equal to the time of the periodic location update, which is determined by the network configuration, typically 1 to 3 hours. Subsequent calls can be made when the user is reassigned in the remaining MSCs.

The specific signaling flow chart is shown in Figure 2, which is a schematic diagram of the process of recovering the called user of the faulty mobile switching center in the prior art, and the implementation process is as follows: the calling party (such as PTSN MSC) The location register HLR sends out a request routing message; if the location information stored in the HLR is MSC1, but if the MSC1 fails at this time, and the HLR still sends a message requesting the provisioning roaming number to the failed MSC1, the calling user fails. . Only after the user has made a location update, for example, the user is re-registered and assigned in another MSC (such as MSC2), the called party can succeed, and it takes a long time to re-allocate all users (generally 1 to 3 hours), and is equal to the period. The time of the location update is determined by the network configuration. The location update includes a caller update and a periodic update, where the caller update refers to a location update initiated by the user, for example, a location update request that occurs after the user moves from one cell to another, or the user makes a The calling service, such as calling or sending a short message, etc.; the periodic update refers to a location update automatically initiated by the user after a predetermined period of time.

It can be seen that in the prior art, when one MSC fails, the maximum time that the corresponding user cannot be called successfully is equal to the periodic location update time. After the user makes a caller update or periodic location update, the location information in the HLR is updated, and the HLR sends a message requesting the provision of the roaming number to the normal MSC2, and the call to the corresponding user can be successful. However, when the called user of the failed mobile switching center does not perform location update, or during the time period during which the location is updated, the user cannot be called, causing the call to be delayed, and thus the corresponding recovery time is also long.

Summary of the invention

The embodiment of the invention provides a call recovery method, device and system, so that when a mobile switching center fails, the called user who is not updated by the location or the called user in the location update period can be called quickly. Reduce call recovery time.

To this end, an embodiment of the present invention provides a call recovery method, where the method includes the steps of: notifying a user belonging to a faulty mobile switching center to perform location update;

Reassign the normal mobile switching center to the user after the location update, and resume the subsequent call of the user.

Correspondingly, the embodiment of the present invention further provides a call recovery device, where the device includes: a control unit, configured to notify a user belonging to the faulty mobile switching center to perform location update; and a call recovery unit, configured to be a user after the location update Reassign the normal mobile switching center and resume subsequent calls to the user.

In addition, an embodiment of the present invention further provides a call recovery system, where the system includes: a control unit and a mobile switching center, where The control unit is configured to notify a user belonging to the faulty mobile switching center to perform location update, and forward the location update response message to a normal mobile switching center;

The mobile switching center is configured to complete subsequent calls of users belonging to the faulty mobile switching center. In the embodiment of the present invention, after the mobile switching center fails or the access network to the mobile switching center fails, the called user who is not in the location update or the called user in the location update period can be called quickly. , which shortens call delay and shortens call recovery time.

DRAWINGS

1 is a schematic structural diagram of an Iu-Flex networking in the prior art;

2 is a schematic diagram of a called process after a mobile switching center fails in the Iu-Flex in the prior art;

3 is a flow chart of a call method in the event of a network failure according to an embodiment of the present invention; FIG. 4 is a schematic diagram showing the principle of a call process after a mobile switching center fails in the Iu-Flex according to an embodiment of the present invention;

5 is a flowchart of a call recovery method in a network failure according to a first embodiment of the present invention; FIG. 6 is a flowchart of a call recovery method in a network failure according to a second embodiment of the present invention; FIG. 8 is a schematic structural diagram of a call recovery system in the case of a network failure according to a fourth embodiment of the present invention; FIG. detailed description

The invention will now be further described with reference to the accompanying drawings and embodiments.

In the Iu-Flex or A-Flex networking, in the case of a certain MSC failure, the control unit (such as the RNC or BSC) in the network can notify the faulty MSC in the shortest time. The user initiates a location update and reassigns to other normal MSCs connected to the RNC or the BSC, thereby solving the problem that the user after the MSC failure may not be called for a long time.

In the embodiment of the present invention, the control unit (such as RC or BSC) in the network is in the network, whether the calling user initiates a call to the user corresponding to the MSC1, or in the absence of a call service. The status of the mobile switching center is detected in real time or at a time. Once the failed MSC is found, the user of the failed MSC is notified to enable the user to perform a location update.

When the user accesses the network (for example, location update or call), the following letter is recorded in the RNC or BSC. Information: User identification, user location information, MSC information to which the user belongs, and the status of the user, but the recorded information is not limited to the above content, and all information related to the access user may be stored in the RNC or BSC.

Please refer to FIG. 3, which is a flowchart of a method for calling a network failure according to a first embodiment of the present invention. The method includes the steps of:

Step 301: Notifying a user belonging to the faulty mobile switching center to perform location update;

Step-by-step 302: Reassign the normal mobile switching center to the user after the location update, and resume the subsequent called of the user.

In order to facilitate the understanding of the present invention by those skilled in the art, a schematic diagram of the call process after the mobile switching center fails in the Iu-Flex networking is first introduced. Specifically, as shown in FIG. 4, when an MSC fails to be enabled, the RNC or the BSC notifies the user belonging to the failed MSC to initiate a location update, and completes registration of other MSCs in the pool, so that the user is not affected. After the RNC or the BSC finds that a mobile switching center (for example, MSC1) is unavailable, the R C or the BSC sends a location update notification message to the user belonging to the MSC1 to notify the user to initiate a location update. The user sends a location update response message to the RNC or BSC, and the RNC or BSC selects a normal MSC, as shown in the figure MSC2, and transfers the location update response message of the user to MSC2 to complete registration in MSC2.

This call recovery process will be described in detail below in conjunction with specific embodiments:

Referring to FIG. 5, it is a flowchart of a method for calling in the event of a network failure according to the first embodiment of the present invention. This embodiment is applicable to wideband code division multiple access (WCDMA), code division multiple access (CDMA), time division-synchronization code division multiple access (TD-SCDMA) or GSM, but can also be applied to other communication systems.

As shown in FIG. 5, first, in step 501, when the network is normal, the RNC records the following information as long as the user accesses the network: the user identifier, the user location information, the MSC information to which the user belongs, and the status of the user. However, the recorded information is not limited to the above, and all information related to the access user can be stored in the internal memory of the RNC.

Then, in step 502, the RC determines the available state of the MSC, that is, acquires the fault condition of the MSC. The manner in which the RNC acquires an MSC fault condition includes: discovering a fault of the MSC by active detection; or passively receiving information (eg, other network element devices) from other devices to notify the MSC of the fault. T/CN2007/001041

One 5—

The RNC can detect the fault condition of the MSC in an active manner. For example, a handshake mechanism is established between the RNC and the MSC, or a fault condition is obtained by determining the link status. If a handshake mechanism is established between the RNC and the MSC, when the handshake is successful, the MSC is working normally, and when the handshake fails, the MSC is faulty. A handshake signal is a series of mutually recognizable signals that occur between two computing devices to communicate or communicate information.

The RNC can also obtain the fault condition by judging the link status. For example, the RNC determines the link state with the MSC. When the link between the RNC and the MSC can reach the MSC signaling point, the RNC judges that the MSC is normal; and when the link between the RNC and the MSC cannot reach the link At the MSC signaling point, the RNC determines that the MSC has failed.

The RNC can also passively obtain information about whether the MSC is faulty, for example: Not notified by the network management system

If an MSC of the R C fails, the notification process may be automatically notified by the network management system or manually notified; or the other MSC (such as other normal MSCs in the resource pool) may notify the R C that an MSC has failed.

In step 503, when the RNC determines that there is a MSC failure, the RNC sends a location update notification message to the user of the failed MSC according to the user data stored in the memory of the RNC. In this embodiment, the location update notification message is an RC direction. The paging message sent by the user, so as to notify the user in the faulty MSC to initiate a location update, to complete the registration to other normal MSCs in the resource pool, so that the called process of the user in the faulty MSC is not affected.

The process of location update initiated by the user includes: the user equipment sends the updated user identifier, the user location information, the MSC information of the user, and the status of the user to the HLR. The location update process is well known to those of ordinary skill in the art and will not be described herein. After the user's location is updated, the user re-registers in the normal MSC, and the MSC information in the HLR is also updated, and the subsequent call of the user can be successful.

At step 505, after receiving the message sent by the RNC, the user responds to the message. The user sends a paging response message to the RNC, and then to a normal MSC selected by the RNC (e.g., MSC2), and transfers the user's paging response message to MSC2 to complete registration in MSC2.

In step 505, when the paging response message is sent to the RNC, the RNC needs to select an MSC from all normal MSCs (ie, step 504) for roaming number assignment and call. Household operations. The method for the RNC to select a normal MSC from the resource pool may be various suitable algorithms, for example: randomly selecting one MSC in all normal MSCs in the resource pool, or selecting one MSC from the round robin. The following takes the wheel-selection method as an example. If a fault occurs in a mobile switching center MSC1, for the user of the mobile switching center MSC1, the RNC needs to call the user of the MSC1 in turn, and after calling the first user, the RNC takes the user. The response message is forwarded to a normal mobile switching center MSC2. When the RNC calls two users, the second user's response message is forwarded to other normal mobile switching centers, for example, MSC3 is selected in sequence order. By analogy, the users in the faulty mobile switching center MSC1 are alternately assigned to other normal mobile switching centers.

The method for selecting the normal MSC by R C further includes: selecting the MSC with the smallest load according to the load condition of the MSC. That is to say, by calculating the MSC load in the resource pool, the MSC with the smallest load is selected, which is more beneficial to load sharing and balance the load between the MSCs. The algorithm for load sharing may also adopt any suitable algorithm in the prior art.

The RNC can also select a normal MSC by static configuration. The static configuration refers to a fixed configuration of an alternative working relationship of some MSCs, that is, when a specified MSC fails, the RC selection is preset as an alternate mobile switching center. The MSC works instead of it. For example, the MSC3 is configured as an alternate mobile switching center of the MSC1. When it is detected that the MSC1 fails, the MSC3 is enabled to make a call to the user in the MSC1.

At step 506, MSC2 assigns a temporary subscriber identity TMSI to the subscriber. At this time, there is no user data in MSC2, which first assigns TMSI to the user for identity recognition when MSC2 communicates with the user.

Moreover, in step 507, MSC2 also initiates an analog location update, recovers user data in MSC2, and updates the MSC/Visit Location Register VLR data in the Home Location Register HLR.

Referring to FIG. 6, a flowchart of a call recovery method in the event of a network failure according to a second embodiment of the present invention will be described by taking the application in the CDMA field as an example. In this embodiment, the base station system controller BSC serves as a control unit of the system. The specific call recovery process is as follows:

First, in step 601, when the network is normal, as long as a user accesses the network, the BSC records the following information: user identity, user location information, MSC information to which the user belongs, or user. The status, but the recorded information is not limited to the above, and all information related to the access user can be stored in the memory inside the BSC.

At step 602, the BSC acquires a fault condition of the MSC. The method for obtaining the MSC fault condition by the BSC is the same as that of the foregoing embodiment, that is, the fault of the MSC can be discovered through active detection, or the fault information of the MSC is notified by other network elements or devices.

For example, after the BSC finds that the mobile switching center MSC1 is faulty by establishing a handshake mechanism, in step 603, the BSC sends a "registration request command egistration to the user belonging to the faulty mobile switching center MSC 1 according to the user data stored in the memory of the BSC. Request Order" message to notify the user to register.

When the user receives the "Registration Request Order" message, in step 604, a "Registration Response Registration Message" message is returned to the base station system controller BSC indicating that the user is to register in the new MSC.

In step 605, an MSC needs to be selected from all normal MSCs. The method of selecting a normal MSC may adopt various suitable algorithms, for example: randomly selecting one MSC in all normal MSCs in the resource pool, or using a round robin method from all Select one MSC in the normal MSC;

For the load condition of the MSC, select the MSC with the smallest load; or select the designated normal MSC by static configuration.

In step 606, the BSC sends a "Location Update Request Location Update Request" message to the normal MSC2 to inform the normal mobile switching center user that the location update is based on the communication protocol in the CDMA system.

In step 607, the normal mobile switching center MSC2 returns a "Location Update Accept Location Update Accept" message to the BSC indicating that the mobile switching center accepts the location update made by the user.

Finally, in step 608, the BSC returns a "Registration Accept Command" message to the user to complete the registration of the user in MSC2. Therefore, all users in the failed MSC1 can re-register in the normal MSC2, so that subsequent calls can be made to these users. The subsequent call flow is a common technique in CDMA systems and will not be described too much here.

Please also refer to FIG. 7, which is a schematic structural diagram of a call recovery apparatus in the event of a network failure according to a third embodiment of the present invention. The apparatus includes: a failure determining unit 71, a control unit 72, and a call restoring unit 73. The fault determining unit 71 is configured to determine whether a fault occurs in the mobile switching center to which the calling user belongs. The control unit 72 is configured to notify the user belonging to the faulty mobile switching center to perform location update. The call recovery unit 73 is configured to reassign the normal mobile switching center to the user after the location update, and restore the subsequent called party of the user.

The control unit 72 includes: an information transmitting unit 721, a selecting unit 722, and a location updating unit 723. The information sending unit 721 is connected to the fault determining unit 71, and configured to send a paging message or a registration request command message to the user of the faulty mobile switching center; the selecting unit 722 is connected, and the information sending unit 721 is configured to receive the Describe a paging message or a registration request command message, and select a normal mobile switching center for the user, and send a corresponding paging response message or registration response command message to the normal mobile switching center; the location updating unit 723, and the selecting unit 722 is connected to initiate location update of the user and complete registration of the user in a normal mobile exchange.

The implementation process is as follows: When there is a user call, the fault determining unit 71 first determines the available state of the MSC, that is, obtains the fault condition of the MSC, and sends the fault information to the information sending unit 721, and the obtaining process is obtained by the RNC or the BSC. The implementation process of the MSC fault condition is the same, that is, the fault of the MSC can be discovered through active detection, or the fault information of the MSC is notified by other network elements or devices. The information transmitting unit 721 transmits the failure information to the selection unit 722 through a paging message or a registration request command message. When receiving the paging message or the registration request command message, the selecting unit 722 selects a normal mobile switching center for the user, and sends a corresponding paging response message or registration response command message to the normal mobile switching center; The location update unit 723 is configured to initiate location update of the user, and complete registration of the user in a normal mobile exchange. After the location update is completed, the call recovery unit 73 reassigns the normal mobile switching center to the user after the location update, and restores the subsequent called party of the user.

Preferably, the device may further include a user data storage unit (not shown) connected to the fault determining unit for storing user data information when the user accesses the network.

Additionally, in practical applications, the device can be integrated in a radio network controller or base station system controller.

Referring to FIG. 8, FIG. 8 is a structural diagram of a call system in the event of a network failure according to a fourth embodiment of the present invention. As shown, in the present embodiment, the mobile station 81, the control unit 82, the mobile switching center (shown as MSC 831 and MSC 832 in the figure) and the user data storage unit 84 are included. 41

One nine one

The control unit 82 is configured to record user data when the user accesses the network, and notify the user belonging to the faulty mobile switching center 831 to initiate a location update. The specific composition and function are the same as those of the control unit in FIG. 7. For details, refer to the above, and details are not described herein again. In this embodiment, the control unit may be implemented by a software module in a radio network controller RNC or a base station system controller BSC or a corresponding hardware logic unit. The control unit may also be integrated in an access layer of the network for receiving messages sent by the user terminal.

The mobile switching center MSC 832 is used for user registration, and when the registration is completed, the mobile switching center 832 can establish a connection with an external calling party. There are multiple mobile switching centers in the resource pool, and the multiple mobile switching centers may establish a connection with a control unit (such as an RNC or a BSC), when one of the mobile switching centers fails (such as the mobile switching center in the figure) In MSC 831, the users in the failed mobile switching center will re-register in other normal mobile switching centers (such as MSC 832 in the mobile switching center in the figure). Thus, the called flow of the user in the failed mobile switching center can continue.

The user data storage unit 84 is connected to the control unit 82 for storing user data. The storage unit may be implemented by a memory in a radio network controller RNC or a base station system controller BSC, or may be implemented by a memory connected to the RNC or BSC through an internal interface. The user data mainly includes: a user identifier, user location information, mobile switching center information to which the user belongs, and a status of the user. However, in actual applications, not only the foregoing information may be included, but the user data is information, such as a location, a status, and the like, used by the control unit to page the user, and the data is recorded in the user data storage by the RNC or the BSC when the user accesses the network. In the unit. When the control unit issues a paging message to the user to notify the location update, the user data storage unit is first acquired in the user data storage unit to page the user.

In the embodiment of the present invention, after the mobile switching center fails or the access network to the mobile switching center fails, the RC or the BSC notifies the user of the faulty mobile switching center to initiate location update in the shortest time. The called service of the user belonging to the faulty mobile switching center is not affected, and the time when the called user belonging to the faulty mobile switching center is not updated by the location or the location is updated is solved in the prior art due to the MSC failure. Within, the user cannot be called. That is, when the mobile switching center in the network fails or the access network to the mobile switching center fails, the link fails. After that, the user of the faulty mobile switching center is notified to initiate a location update, and the user is reassigned the normal mobile switching center after the location is updated, so as to restore the subsequent called party of the user. This reduces call delays and also reduces call recovery time. It also improves network quality and customer satisfaction.

The embodiments of the present invention described above are not intended to limit the scope of the present invention. Any modifications, equivalents, and improvements made within the spirit and scope of the present invention are intended to be included within the scope of the appended claims.

Claims

Rights request

A call recovery method, comprising:

Notifying users belonging to the faulty mobile switching center to perform location update;

After the location is updated, the user reassigns the normal mobile switching center and resumes the subsequent call of the user.

2. The call recovery method according to claim 1, wherein the process of notifying a user belonging to the fault mobile switching center to perform location update is:

The radio network controller sends a paging message to the user belonging to the faulty mobile switching center; after receiving the paging response message fed back by the user, selecting a normal mobile switching center for the user, and sending the paging response message To the normal mobile switching center;

The normal mobile switching center initiates an analog location update to complete registration of the user in a normal mobile exchange.

3. The call recovery method according to claim 2, wherein the process further comprises: the normal mobile switching center assigning a temporary user identifier to the user to identify an identity when communicating with the user.

4. The call recovery method according to claim 1, wherein the process of notifying a user belonging to the fault mobile switching center to perform location update is:

The base station controller sends a registration request command message to the user belonging to the faulty mobile switching center; after receiving the registration response message fed back by the user, selecting a normal mobile switching center for the user, and sending the location update to the normal mobile switching center Request message

After receiving the accepted location update response message fed back by the normal mobile switching center, the registration accept command message is sent to the user to complete registration of the user in the normal mobile exchange.

The call recovery method according to claim 1, wherein the method further comprises: determining whether a mobile switching center to which the calling user belongs has a failure.

The call recovery method according to claim 5, wherein the manner of determining whether the mobile switching center to which the calling user belongs is faulty comprises at least one of the following:

Determine by establishing a handshake operation or judging the link status;

It is determined by the fault notification sent by the network management system or the fault information sent by the network element.

The call recovery method according to claim 2 or 4, wherein the manner of selecting a normal mobile switching center for the user comprises at least one of the following:

Rotate selection for all normal mobile switching centers;

According to the load situation of each mobile switching center, select the mobile switching center with the smallest load; select a normal mobile switching center according to the static configuration;

Randomly selected in all normal mobile switching centers.

.

The call recovery method according to claim 7, wherein the static configuration is another mobile switching center previously designated by the mobile switching center.

9. A call recovery device, comprising:

a control unit, configured to notify a user belonging to the faulty mobile switching center to perform location update; and a call recovery unit, configured to reassign the normal mobile switching center to the user after the location update, and restore the subsequent called party of the user.

The call recovery device according to claim 9, wherein the control unit comprises: an information sending unit, configured to send a paging message or a registration request command message to a user of the faulty mobile switching center;

a selecting unit, configured to receive the paging message or the registration request command message, and select a normal mobile switching center for the user, and send a corresponding paging response message or a registration response command message to the normal mobile switching center;

a location update unit, configured to initiate location update of the user, and complete registration of the user in a normal mobile exchange.

The call recovery device according to claim 10, wherein the device further comprises: a failure determining unit, connected to the information sending unit, configured to determine whether a mobile switching center to which the calling user belongs is faulty.

The call recovery device according to claim 9, wherein the device further comprises: a user data storage unit, configured to store user data information when the user accesses the network.

The call recovery device according to any one of claims 9 to 12, characterized in that the device can be integrated in a radio network controller or a base station system controller.

A call recovery system, comprising: a control unit and a mobile switching center, wherein The control unit is configured to notify a user belonging to the faulty mobile switching center to perform location update, and forward the location update response message to a normal mobile switching center;

The mobile switching center is configured to complete subsequent calls of users belonging to the faulty mobile switching center.

The call recovery system according to claim 14, further comprising:

The fault determining unit is connected to the control unit and configured to determine whether the mobile switching center to which the calling user belongs is faulty.

The call recovery system according to claim 14 or 15, wherein the control unit comprises:

An information sending unit, configured to send a paging message or a registration request command message to a user of the faulty mobile switching center;

17. The call recovery system of claim 14 wherein said control unit is integrated in a radio network controller or base station system controller.

The call recovery system according to claim 16, further comprising: a user data storage unit, connected to the fault determination unit or the information sending unit, for storing user data information when the user accesses the network.