EP2286609A2

EP2286609A2 - Mobile communications system and method

Info

Publication number: EP2286609A2
Application number: EP09742142A
Authority: EP
Inventors: Inigo Mendizabal
Original assignee: France Telecom SA
Current assignee: Orange SA
Priority date: 2008-05-07
Filing date: 2009-05-07
Publication date: 2011-02-23
Also published as: GB2463632B; WO2009135924A3; GB0808256D0; GB2463632A; WO2009135924A2

Abstract

Embodiments of the invention relate to a network operations database such as a VLR, with data from a subscriber database such as a HLR on an individual subscriber basis, outside of the normal operation of the VLR, a MSC linked thereto, and/or HLR. In one embodiment, a VLR is updated with data from a new HLR for a subscriber during subscriber migration. This ensures that subscribers can access normal network services such as receiving calls and messages without degradation of service during subscriber migration. In another embodiment, a VLR is updated with data from a HLR for a subscriber so as to switch serving VLRs for the subscriber from a VLR of one network to another VLR of another network.

Description

Mobile communications system and method

Field of the Invention

The present invention relates to updating a network operations database in a communications network, for example a visitor location register (VLR), with data from a subscriber database, for example a home location register

(HLR), outside of the normal operation of the network operations database, a network operations node linked thereto, and/or the subscriber database. In particular, but not exclusively, the invention is suited to updating a VLR with data from a HLR in a mobile communications network using standard Mobile

Application Part (MAP) messages.

Background of the Invention

The HLR is a central subscriber database in a mobile communications network that contains details of each mobile phone subscriber that is authorized to use network services provided by the network operator. An example of such a network is a Global System for Mobile communications (GSM) network. The HLR stores details of every subscription which corresponds to a Subscriber Identity Module (SIM) issued by the network operator. The details are stored in the form of subscriber records that are keyed by a unique identifier associated with the SIM called an International Mobile Subscriber Identity (IMSI).

The Mobile Switching Centre (MSC) is a primary service delivery node for networks such as GSM, responsible for coordinating the setting-up of calls to and from subscribers. The VLR is linked to an MSC, and in charge of temporarily storing subscription data for those subscribers currently situated in the service area of the corresponding MSC/VLR, as well as holding data on their location at a more precise level than the HLR. Under current practice, a VLR function is always integrated with each MSC. The data stored in the MSC/VLR have either been received from the HLR, or collected from the mobile station (MS). The MSC/VLR may contact the HLR using a subscriber identity code (either the subscriber's IMSI or Mobile Subscriber ISDN (MSISDN)) or the HLR global title. The subscriber identity code is normally used when the HLR global title is unknown to the MSC/VLR e.g. during authentication request, location updates, and call and SMS termination when only the MSISDN of the called party is known. The HLR global title is used for subsequent operations after a location update.

The MAP is the application- layer protocol for signaling between fixed infrastructure nodes of a mobile communications network, such as the HLR, MSC, VLR, etc, according to MAP standard 29:002

As the number of subscribers increases, the number of HLRs may become insufficient to maintain subscriber data necessitating the addition of data and/or transaction capacity in additional HLRs. If a HLR becomes full, it may be desirable, for load balancing, to partition the HLR and to transfer responsibility of storing some of its data to another HLR. Furthermore, as the quality (including continuity) of service demanded increases, backup facilities may be desirable to restore and maintain continuity of service in case of HLR breakdown. A third situation where subscriber migration may be desirable is when a newly developed HLR is deployed. Moreover, when a subscriber upgrades his/her service package to include a service not supported by its serving HLR, subscriber migration to another HLR which supports the service may be desirable. There may be other reasons why subscriber migration is desired.

In each case subscriber migration is desirable, however difficulties arise in transferring active subscriber data. In all these cases normal network subscriber service is suspended while the data is transferred in the network as the active subscriber data cannot be accessed while there is no single and settled HLR address, i.e. no single and settled subscriber's HLR global title, to which this data corresponds. The process of active data transfer typically involves normal service being interrupted whilst network operations databases are updated from the new HLR. This process can take sever hours and represents a significant disruption of normal service to subscribers.

It is known to use a MAP Reset message to synchronize subscriber data between a MSC/VLR and a HLR, when the HLR is recovering from a fault. Figure 1 illustrates a known method for synchronizing subscriber data between a MSC/VLR and a HLR in a GSM system when the HLR is recovering from a fault. At step 100 the HLR restores itself to a previously saved state. Next the HLR sends a MAP Reset request message to all the MSC/VLRs in which at least one of the HLR subscribers is known to be located as indicated by the salvaged records at step 105. The MAP Reset signalling message identifies the HLR for all subscribers in the MSC/VLR which are affected.

At step 110, the MSC/VLR marks all affected records as to be checked with the HLR. Marking the records will force the MSC/VLR to perform a MAP Update Location service to update the HLR at the next authenticated radio contact with each affected mobile station (MS).

At step 115, the MSC/VLR waits for an authenticated radio contact from the affected mobile subscriber. At step 120, the MSC/VLR determines whether it has received such an authenticated radio contact. If the MSC/VLR has not received an authenticated radio contact from the concerned mobile subscriber, the MSC/VLR continues to wait in accordance with step 115. Once the MSC/VLR receives an authenticated radio contact from the affected mobile subscriber, the MSC/VLR transmits a MAP Update Location message to the HLR indicating that the MSC/VLR is serving the affected mobile subscriber at step 125. The MAP Update Location message carries (among other information) the subscriber identity and enough information for the HLR to know how to find routing data for the setting up of a mobile terminating call, i.e. the SS7 address of the MSC/VLR.

At step 130 the HLR then determines whether to accept to register the MS in the new MSC/VLR or not by consideration of the subscription limitations of the user. The answer from the HLR is carried to the MSC/VLR in a MAP Update Location Result message in accordance with step 135. If the requesting MSC/VLR receives a negative answer, it erases all information relative to the subscriber. Otherwise and if necessary, it enters the subscriber in its database. Normally, the HLR will then provide the subscriber information the MSC/VLR needs. This is done by sending one or more MAP Insert Subscriber Data messages in accordance with step 140, which is acknowledged by the MSC/VLR through a MAP Insert Subscriber Data Result message.

A problem with the MAP Reset procedure is that, since a range of IMSIs is always identified in the MAP Reset message transmitted between a HLR and a MSC/VLR, subscriber data relating to all IMSIs of the range are updated. For example in HLR fault recovery as described above, all IMSIs in the HLR's backup memory, or a group of subscribers whose IMSI leading digits are equal to that of the IMSIs specified in the MAP Reset request, are transmitted, and MAP Location Update messages are subsequently transmitted for every IMSI. This method therefore generates a vast amount of wasted signaling if not all subscriber data in a range need to be synchronized between the HLR and all relevant MSC/VLR.

In a mobile telecommunications system comprising a mapping network node to intercept and redirect messages to HLRs, all responses to MAP Reset (e.g. MAP Location Update messages) go through the mapping network node. This means generating even more signaling and resource wastage.

MAP Reset procedures are also time-consuming, during which normal network subscriber service for relevant subscribers may be interrupted or degraded. MAP Reset procedures rely on triggers from subscribers to initiate location update and thus the synchronization between HLRs and MSC/VLRs. The duration of a MAP reset depends on the number of subscribers affected and their habits e.g. the frequency a subscribers originates events that cause the MSC/VLR to restore its data.

Figure 2 illustrates a known method in a GSM system when a MSC/VLR is recovering from a fault using MAP Provide Roaming Number Request messages and MAP Restore Data messages. At step 400 the MSC/VLR, which does not have a non-volatile backup memory for its dynamic subscriber data, deletes all IMSI records which remain in its dynamic memory. At step 405 the MSC/VLR waits for contact from the HLR associated with a mobile subscriber. The MSC/VLR determines whether it has received a MAP Provide

Roaming Number Request message from the HLR in accordance with step 410. If the MSC/VLR has not received a MAP Provide Roaming Number Request message, the MSC/VLR continues to wait for a contact from the HLR in accordance with step 405. If the MSC/VLR has received a request for roaming number from the HLR, the MSC/VLR sends a MAP Restore Data message, including an identifying code for the concerned subscriber whose data is being restored, to the HLR indicating that the MSC/VLR has experienced a fault in accordance with step 415. MAP restore data process is normally invoked by the VLR on receipt of a MAP Provide Roaming Number message, which provides an IMSI unknown to the VLR, or an IMSI known to the VLR but with the indicator "Confirmed by HLR" set to "Not confirmed". During MSC/VLR fault recovery, MAP Restore Data messages are always sent in response to a MAP Provide Roaming Number message, because all IMSI records in the MSC/VLR have been deleted in step 400. The HLR will then send all data to the MSC/VLR that are to be stored in the subscriber's IMSI record contained in one or more MAP Insert Subscriber Data messages in accordance with step 420.

The above MSC/VLR fault recovery procedure is preformed for all subscribers in the MSC/VLR's dynamic memory. As a first step, the MSC/VLR deletes all its IMSI records from its dynamic memory. Subsequently, MAP Provide Roaming Number Request messages and MAP Restore Data messages are sent for every subscriber in its dynamic memory. This method therefore generates a vast amount of wasted signaling and resource usage if not all subscriber data need to be synchronized between the MSC/VLR and all relevant HLRs, especially if the network comprises a mapping network node to intercept and redirect messages to HLRs. This procedure may be time-consuming, during which normal network subscriber service such as short message service (SMS) termination, location based services for relevant subscribers are interrupted or degraded. It relies on triggers from the HLR to initiate roaming number requests and thus the synchronization between HLRs and MSC/VLRs. MAP Provide Roaming Number Request messages are normally only sent from the HLR to the MSC/VLR during the interrogation stage of a mobile terminating call routing, i.e. when someone calls the MS, using e.g. another MS or a landline.

As can be seen from the prior art, the exact moment MAP restore takes place depends on some unrelated external processes initiated at the MS or the HLR, for example first call attempt termination on the subscribers or first call originated by subscribers.

It would be desirable to provide a more efficient and timely process for updating a network operations database, for example a VLR, in a communications network with data from a subscriber database, for example a HLR.

Summary of the Invention

In accordance with one aspect of the present invention, there is provided, in a mobile communications network, a method for updating a network operations database with data from a subscriber database for a subscriber, the method comprising: establishing at a first network node, separate from a network operations node, that at least some current data relating to the subscriber is not available in the network operations database; and in response to said establishing, initiating the transmission of a data access signaling message to the network operations node, the data access signaling message including an identifying code for the subscriber, the data access signaling message being of a type of signaling message which causes the network operations node: a) to attempt to access current data for the subscriber in the network operations database; and b) if the at least some current data relating to the subscriber is not available in the network operations database, to obtain current data relating to the subscriber from the subscriber database.

It is envisaged that sometimes it is desirable for a network operations database, for example a VLR, to be synchronized with the subscriber data in a subscriber database, for example a HLR, on an individual subscriber basis, e.g. during subscriber migration to ensure that subscribers can access normal network services such as receiving calls and messages without degradation of service or when switching serving network operations nodes for a subscriber from a network operations node of one network to a network operations node of another network. Subscriber migration refers to subscriber data migration from one subscriber database to another subscriber database. Embodiments of the invention provide a system and method for updating a network operations database with data from a subscriber database for an individual subscriber overcoming the limitations of the prior art.

Note that, normally, a data access signaling message is transmitted to a network operations node before the system has established that the current data relating to the subscriber is not available in the network operations database.

Embodiments of the present invention subvert this procedure by sending such a message even once it has been established that the relevant data is unavailable.

In another embodiment of the present invention, the network operations node obtains current data from the subscriber database by transmitting a data obtain signaling message to the subscriber database. In one arrangement, the data obtain signaling message is a MAP Restore Data message.

In another embodiment of the present invention, the establishing comprises: transmitting a data deletion signaling message to the network operations node, thereby causing deletion of the data relating to the subscriber from the network operations database. In one arrangement the data deletion signaling message is a MAP Cancel Location message. In another arrangement the data access signaling message is a MAP Provide Roaming Number message.

It is advantageous to utilise standard MAP messages supported widely among different vendors, e.g. MAP Restore Data messages, MAP Cancel

Location messages and MAP Provide Roaming Number messages. At least some of these messages are typically used in processes other than in updating a network operations database, for example a VLR, with data from a subscriber database, for example a HLR, for a subscriber. This means the first network node is preferably programmed so as to handle these standard messages in a non-conventional way.

It is further advantageous and unexpected to program the first network node to transmit a MAP Provide Roaming Number Request message after transmitting a MAP Cancel Location message, instead of during mobile terminating call routing.

It is further advantageous to utilise the standard response of a network operations node, for example a MSC, to the receipt of a MAP Provide Roaming Number message when at least some current data relating to the subscriber is not available in the network operations database, the standard response being transmitting a MAP Restore Data message to a subscriber database to obtain current data relating to the subscriber.

In another embodiment of the present invention, the method comprises transferring responsibility of storing data relating to a subscriber from a first subscriber database to a second subscriber database, prior to the network operations database obtaining the data from the second subscriber database for the subscriber.

A network operations database can thus be synchronized with subscriber data in a subscriber database on an individual subscriber basis, e.g. during subscriber migration to ensure that subscribers can receive calls and messages without degradation of service. In another embodiment of the present invention, the establishing comprises: receiving a data update signaling message, the data update signaling message indicating that the subscriber is currently being served by a different network operations node.

The present invention can thus be used to switch serving network operations nodes for a subscriber from a network operations node of one network to a network operations node of another network. This can reduce cost associated with using a network operations node of a visited network. In accordance with another aspect of the present invention, it is provided a message processing system, responsive to the receipt of an identifying code for a subscriber, and a network operations database identity, arranged to transmit a first message to a network operations node thereby causing deletion of at least some current data relating to the subscriber from the network operations database; and, responsive to the receipt of a second message indicating the completion of said deletion, to initiate the transmission of a third message to the network operations node providing the network operations node with the identifying code for the subscriber such that the network operations node is caused to obtain current data relating to the subscriber from a subscriber database.

In accordance with another aspect of the present invention, there is provided, in a mobile communications network, a method for subscriber migration from a first subscriber database to a second subscriber database, the method comprising: 1) transferring responsibility of storing data relating to a subscriber from the first subscriber database to the second subscriber database; and

2) in response to confirmation that the second subscriber database has assumed responsibility, triggering a network operations node to refresh subscriber data from the second subscriber database by sending a data obtain message. Further features and advantages of the invention will become apparent from the following description of preferred embodiments of the invention, given by way of example only, which is made with reference to the accompanying drawings.

Brief Description of the Drawings

Figure 1 is a flow chart showing a known method for synchronizing subscriber data between a MSC/VLR and a HLR in a GSM system when the HLR is recovering from a fault. Figure 2 is a flow chart showing a known method for synchronizing subscriber data between a MSC/VLR and a HLR in a GSM system when the MSC/VLR is recovering from a fault.

Figure 3 is a schematic diagram of a communications network within which embodiments of the invention may operate. Figure 4 is a schematic diagram showing a portion of the communications network shown in Figure 3.

Figure 5 is a flow chart showing a schema relating to the present invention.

Figure 6 is a signaling chart showing an embodiment of the present invention for updating a MSC/VLR with data from a HLR.

Figure 7 signaling chart showing another embodiment of the present invention for updating a MSC/VLR with data from a HLR.

Detailed Description of the Invention Embodiments of the invention are concerned with updating a network operations database, for example a VLR, with data from a subscriber database, for example a HLR, for a subscriber. Some embodiments are concerned with updating a network operations database with data from a subscriber database for a subscriber during subscriber migration. Further embodiments relate triggering a network switch of a subscriber, which includes transferring responsibility from a network operations database of one network to a network operations database of another network and/or transferring responsibility from a network operations node of one network to a network operations node of another network.

Embodiments of the invention may use standard MAP signaling messages. This allows the implementation of the present invention on legacy equipment and new equipment alike.

Methods and systems for updating a network operations database with data from a subscriber database for a subscriber according to embodiments of the invention will be described in detail below, but first an overview of a mobile communications network within which embodiments can operate will be described with reference to Figure 3, which shows a mobile communications network 10, such as a GSM network, comprising a network operations node, for example an MSC/VLR 2 connected via communications links to a number of base station controllers (BSCs) 4. The BSCs 4 are dispersed geographically across areas served by the MSC/VLR 2 and, as is known in the art, each BSC 4 controls one or more base transceiver stations (BTSs) 6 located remote from, and connected by, further communications links to, the BSC 4. Each BTS 6 transmits radio signals to, and receives radio signals from, MSs 8 which are in an area (known as a "cell") served by that BTS 6.

The MCS/VLR 2 is also connected via communications links to other MSC/VLRs (not shown), in the remainder of the communications system 10, and to a public switched telephone network (PSTN), public data network (such as the Internet), etc. which are not illustrated. The network is provided with a subscriber database, for example a HLR 12, which is arranged to provide the MSC/VLR 2 with data relating to a user upon request (typically populating a network operations database, for example a VLR, which is part of, or accessible by, the switching part of the MSC/VLR 2). The MSC/VLR 2 is capable of handling service provision for both post-pay or contract users and prepaid users of the network in the area it serves. Thus, users may originate or receive a range of data, including multimedia, video, voice, data or fax calls or sessions, short messages using the SMS, email messages, enhanced or multimedia messages, and may access data resources over private or public data networks such as the Internet. Signaling and data in respect of services provided to MSs 8 are routed via MSC 2, and delivery of SMS messages is handled by store-and-forward nodes such as SMSC 20.

The telecommunications network 10 comprises a provisioning system 16, which is capable of independently accessing various network control nodes (such as the HLR 12), triggering updates and modifications to the data stored therein. The provisioning system 16 can be implemented as an intelligent network node in the form of a Service Control Point (SCP) or as an Open Services Architecture (OSA) node; accordingly it can be configured to receive request messages using the MAP, INAP, CAMEL, XML or LDAP protocols. It will be understood by one skilled in the art that the configuration, and thus messaging protocols, will depend on the network communications protocols provided in the network.

As is known in the art, the HLR is a central subscriber database that contains details of each subscriber that is authorized to use the GSM network 10 in the form of subscriber records. Referring also to Figure 4, whilst Figure 3 depicts HLR 12 as a single database it can be, and typically is, maintained as separate databases 12a ... 12f. Conventionally the HLR stores details of every SIM card issued by the network operator; each SIM has a unique identifier called an International Mobile Subscriber Identity (IMSI) which is one of the primary keys to each subscriber record. The IMSI is an identifier that is internal to the network 10 and used to identify one or more devices within the network 10. In addition each HLR record includes the telephone numbers used to make and receive calls to the mobile phone, known as MSISDNs. MSISDNs are external identifiers for use outside of the network to route communications to one or more said devices within the network. In addition the HLR stores data identifying network services accessible by a given subscriber. The network may comprise a further HLR 14. Whilst the further HLR 14 is shown as a separate database in the Figures it will be appreciated that it can be a specific portion of a particular HLR. As shown in Figure 4, in some arrangements the telecommunications network 10 also comprises a Service Location Register (SLR) 15, which intercepts all MAP messages destined for HLR 12, 14 and determines to which physical database (or portion 12a ... 12f) of the HLR the MAP message should be directed. As described in the Applicant's European patent EP-A-0784910, the SLR 15 performs a look-up function based on the IMSI contained within the MAP request message so as to identify which physical HLR 12a ... 12f holds subscriber records corresponding to the requesting device 8.

Figure 5 illustrates a general schema of the present invention. The invention is concerned with updating a network operations database, for example a VLR, with data from a subscriber database, for example a HLR, for a subscriber in a mobile communications network.

At step 500, it is established, at a first network node, separate from a network operations node, that at least some current data relating to the subscriber is not available in the network operations database.

The network operations database may be linked to one or more network operations nodes and in charge of temporarily storing subscription data for those subscribers currently situated in a service area, as well as holding data on their location at a more precise level than the subscriber database, such as the current Location Area Identity (LAI). The LAI may identify under which BSC the MS is currently receiving radio service. This information may be used in the call setup process. Other data stored may include an identifying code for a subscriber, e.g. the IMSI; authentication data; MSISDN; network services that the subscriber is allowed to access; Access Point (GPRS) subscriber; and the subscriber database address of the subscriber.

At least some current data relating to the subscriber may not be available in the network operations database for various reasons, including: no data relating to the subscriber is stored; data relating to the subscriber is stored but marked as not up-to-date or not confirmed; or some data relating to the subscriber is stored and current while some data is missing or marked as not up-to-date or not confirmed.

The fact that at least some current data relating to the subscriber is not available in the network operations database can be established at a first network node positively or passively. An example of positive establishing is to delete at least some current data relating to the subscriber from the network operations database. Another example of positive establishing is to mark at least some of the data relating to the subscriber available in the network operations database as not up to date or as missing some key data. An example of passive establishing is to ascertain at least some current data relating to the subscriber is not available in the network operations database, for example, from information contained in a signaling message transmitted to the first network node.

At step 505, in response to said establishing, the transmission of a data access signaling message, which includes an identifying code for the subscriber, to the network operations node is initiated thereby causing the network operations node to obtain current data relating to the subscriber from the subscriber database.

The data access signaling message is of a type of signaling message which causes the network operations node, firstly, to attempt to access current data for the subscriber in the network operations database. The data access attempt may be a data read attempt, a data write attempt, a data delete attempt or a combination of any two or more of these types of access attempts.

The data access signaling message is also of a type of signaling message which causes the network operations node, secondly, if the at least some current data relating to the subscriber is not available in the network operations database, to obtain current data relating to the subscriber from the subscriber database.

Because it has already been established at a first network node that at least some current data relating to the subscriber is not available in the network operations database at step 500, transmitting a data access signaling message at step 505 to the network operations node, the data access signaling message being of a type as described above, will definitely cause the network operations node to obtain current data relating to the subscriber from the subscriber database.

Therefore this establishment step enables a controlled update of the network operations database with data from the subscriber database and synchronization between the two databases. It further enables a controlled update on on individual subscriber basis. The network operator thus has the capability to restore data an individual subscriber basis and control over the date/time the data restoration takes place i.e. the data restoration takes places when requested by the operator and does not depend on subscriber habits and/or usage of services.

Embodiments of the present invention are concerned with updating a network operations database, for example a VLR, with data from a subscriber database, for example a HLR, for a subscriber during subscriber migration or when switching serving network operations nodes, for example MSCs, for a subscriber from a network operations node of one network to a network operations node of another network. The embodiments are discussed in relation to HLRs and MSC/VLRs; however it is to be understood that it can be applied to other subscriber databases, network operations nodes, and/or network operations databases of a mobile communications network. For example, other examples of a network operations database include a serving GPRS support node (SGSN), a SLR or a gateway location register (GLR) and other examples of a subscriber database include a home subscriber server (HSS), a SLR or a GLR.

The subscriber migration method of the invention is described with reference to Fig 6 and the method ensures that subscribers can access normal network services such as receiving calls and messages without degradation of service during subscriber migration.

The HLR stores subscriber and system data including service feature information for subscribers and current location area data (the MSC and the VLR). The MSC/VLR requests a subscriber's data to be downloaded from an HLR into the MSC/VLR when that subscriber moves into the local area. This data enables the MSC/VLR to determine features subscribed to the subscriber for example and other subscriber information.

The embodiment as illustrated in Fig 6 provides a method and system for subscriber migration from a first HLR 14 to a second HLR 12 overcoming the limitations of existing subscriber migration methods. The embodiment is discussed in relation to HLRs and MSC/VLRs; however it is to be understood that it can be applied to other subscriber databases, network operations nodes, and/or network operations databases of a mobile communications network. For example, another example of a subscriber database is a HSS while another example of a network operations database is a GLR or a SGSN.

Interactions with the MSC/VLR 2 to trigger the update are handled by a first network node 22. The first network node 22 does not wait for a MS to initiate location update procedures or for a HLR to receive a mobile terminating call and the method can be performed on an individual subscriber basis. This allows for normal network subscriber service which is not interrupted for a long period of time thus subscribers can for example receive calls and messages without degradation of service during subscriber migration from one HLR to another HLR.

Referring to Fig 6, an IT provisioning system 16 is instructed to transfer responsibility of storing data relating to a subscriber from a first HLR 14 to the second HLR 12 at step 200, prior to the MSC/VLR 2 obtaining current data from the second HLR 12 for the subscriber. The IT provisioning system 16 is preferably instructed by a second network node 34 transmitting an instruction signaling message to the IT provisioning system 16. The signaling message may contain an identity for the first HLR and/or an identity for the second HLR, such as the global titles thereof.

The second network node 34 can be an administrative network node handling for example the transmission of subscriber data from one HLR to another for load balancing between the HLRs, to transfer subscriber data between a backup HLR and a normal service HLR, or to deploy a newly developed HLR. The second network node 34 can alternatively be a customer service network node handling for example upgrading subscriber service. Other types of network nodes for other purposes are also possible for the second network node 34. The second network node 34 may be implemented as part of the first HLR 14 or another existing network node. The IT provisioning system 16 then obtains information relating to the subscriber from a first HLR 14. The information may include an identifying code for the subscriber, a MSC/VLR identity, an identity for a second HLR such as the global title of the second HLR and/or other subscriber data typically stored in a HLR. An example of such an identifying code for the subscriber is an IMSI. Subscriber data typically stored in a HLR may include an identifying code for the subscriber (e.g. IMSI), MSISDN numbers, network services that the subscriber has requested or been given, GPRS settings to allow the subscriber to access packet service, current location of subscriber (MSC/VLR and/or SGSN) and/or Call divert settings applicable for each associated MSISDN. The IT provisioning system 16 preferably obtains the information relating to the subscriber from a first HLR 14 by transmitting a data request signaling message from the IT provisioning system 16 to the first HLR 14 at step 202 and receiving a data request result signaling message from the HLR 14 at step 205.

The IT provisioning system 16 can be provided with some or all of the above mentioned information relating to the subscriber by an intermediate network node rather than directly from the first HLR 14. Some or all the information may alternatively be provided by another network node other than the first HLR 12, for example the second HLR identity may be provided by the second network node 34 at step 200. Furthermore, the IT provisioning system 16 may be implemented as part of the first HLR 14 or another existing network node.

The IT provisioning system 16 transmits the identifying code for the subscriber, and at least some, but preferably all, of the other subscriber data typically stored in a HLR to the second HLR 12 directly at step 207 or indirectly using the identity for the second HLR. The information is provided to the second HLR 12 so that the HLR 12 can respond to an authentication request relating to the subscriber at step 245, provide current data relating to the subscriber to a MSC/VLR at step 255 and/or assume responsibility of storing data relating to a subscriber from a first HLR to a second HLR.

In this embodiment, there may be provided a mapping network node 15 such as a SLR or a Signaling Transfer Point (STP) providing a service for mapping a subscriber identity code to a HLR identity. A subscriber identity code (either IMSI or MSISDN) has to be used by the MSC/VLR to contact the HLR when only the subscriber identity code, but not the HLR global title, is known to the MSC/VLR, as is the case during subscriber migration from one HLR to another. For these operations addressed on the subscriber identity code it may be necessary to perform a look up to find out the HLR global title where the subscriber record is stored using a mapping network node 15. Once the HLR global title is known to the MSC/VLR, the MSC/VLR can contact the HLR directly and a mapping network node 15 is not needed. The mapping network node 15 is updated at step 206. The updating of the mapping network node comprises: updating the HLR identity (i.e. the HLR global title) mapped for the subscriber from an identity for the first HLR 14 to an identity for the second HLR 12. At step 206, the mapping network node 15 is provisioned with the network identity of the second HLR 12, together with a rule that causes the mapping network node 15 to send signaling messages corresponding to all relevant IMSIs to the second HLR 12.

After updating the mapping network node 15, the IT provisioning system 16 may transmit all or some of the information to the second HLR 12 indirectly via the mapping network node 15. However, the information can alternatively be transferred to the second HLR 12 directly at step 207, i.e. not via the mapping network node 15, before, after or at the same time as updating the mapping network node 15.

After the second HLR 12 receives the information sent from the IT provisioning system 16 and assumes responsibility of storing data relating to a subscriber, a confirmation signaling message is transmitted from the second HLR 12 to the IT provisioning system 16 at step 208. After subscriber migration, subscriber's HLR reference in the VLR, i.e. the global title of the subscriber's HLR, in particular, becomes out of date and needs to be updated. The HLR global title is needed because otherwise at least some subscriber originated MAP traffic which is routed to the HLR using this reference would end up in the old HLR and therefore would be rejected. In order to ensure that these operations can be carried out as normal the subscriber's HLR global title needs to be refreshed to that of the new HLR.

Therefore, in response to the confirmation that the second HLR has assumed responsibility, the MSC/VLR is triggered to refresh subscriber data from the second HLR by sending a message. The second HLR identity has been provided so that the message can be delivered to the second HLR. The second HLR identity is provided to the SLR 15 in this embodiment. However, it can be provided to another network node, such as the MSC/VLR.

After receiving the confirmation that the second HLR 12 has assumed responsibility at step 208, the IT provisioning system 16 transmits an identifying code for the subscriber and an identity for a MSC/VLR 2 to a first network node 22 at step 210 using an identity for the first network node provided for example by the first HLR 14 at step 205, by the second network node 34 at step 200, or by another network node. This information is provided to the first network node 22 so that the first network node 22 can transmit a data deletion signaling message to the MSC/VLR 2 at step 215, thereby causing deletion of at least some current data relating to the subscriber from the MSC/VLR at 222, and/or so that the identifying code for the subscriber can be provided to the MSC/VLR 2 at step 230. The first network node 22 may be a message processing node, responsive to the receipt of an identifying code for a subscriber and a MSC/VLR identity in accordance with step 210, arranged to transmit a first message to the MSC/VLR 2 at step 215 using the MSC/VLR identity, thereby causing deletion of at least some current data relating to the subscriber from the MSC/VLR 2 at step 220; and, responsive to the receipt of a second message indicating the completion of the deletion at step 225, to initiate the transmission of a third message to the MSC/VLR 2 providing the MSC/VLR 2 with the identifying code at step 230 such that the MSC/VLR 2 is caused to obtain current subscriber data relating to the subscriber from a HLR 12.

The first message may be a data deletion signaling message, thereby causing deletion of at least some current data relating to the subscriber from the MSC/VLR. After the data has been deleted from the MSC/VLR 2, the MSC/VLR 2 transmits a second message to the first network node to inform the first network node that the date has been deleted from the MSC/VLR 2. The first network node therefore establishes that at least some current data relating to the subscriber is not available in the network operations database, since it has been deleted.

An example of such a data deletion signaling message is a MAP Cancel Location message. A corresponding example of such a second message is a MAP Cancel Location Result message. MAP Cancel Location messages are normally transmitted from the HLR to a previous MSC/VLR to delete relevant subscriber data from the previous MSC/VLR, after location update procedures are completed from a MS to a new MSC/VLR and then from the MSC/VLR to the HLR. MAP Cancel Location Result messages are standard responding messages to MAP Cancel Location messages.

Another example of a data deletion signaling message which can be used for the purpose of this invention is MAP Delete Subscriber Data message. It may be used to remove key parts of the subscriber data in the MSC/VLR or SGSN but not to cancel the subscriber record. The third message is a data access signaling message, being of the type described above.

In this embodiment, the data access signaling message is a MAP Provide Roaming Number message. It is an example of a read data message of a type suitable for use in the present invention. As mentioned above, MAP Provide Roaming Number messages are normally transmitted from a HLR to a MSC/VLR during interrogation of the HLR in establishing a mobile terminating call. It contains the subscriber's IMSI, and in the case of multi-numbering, the network bearer capability needed for the required service.

In response to receiving the data access signaling message, the MSC/VLR attempts to access the subscriber record indicated by the subscriber identity code in the message and it is determined at the MSC/VLR 2 that at least some current data relating to the subscriber is not available in the MSC/VLR 2 at step 235. The IMSI for the subscriber is either unknown to the VLR, or the IMSI is known to the VLR but the indicator "Confirmed by HLR" is set to "Not confirmed". In response to this determination, the MSC/VLR 2 obtains current data relating to the subscriber from the HLR 12. Before the MSC/VLR obtains current data relating to the subscriber from the HLR 12, the MSC/VLR may transmit a request authentication signaling message to the HLR 12 at step 240. An example of such a request authentication signaling message is a MAP Send Authentication Request message. A request authentication result signaling message may then be transmitted from the HLR 12 to the MSC/VLR 2 at step 245. An example of such a request authentication result signaling message is a MAP Send Authentication Response message. The request authentication signaling message and the request authentication result signaling message may be transmitted via the mapping network node 15 if it is provided in the network. An alternative action to authentication is ciphering setting.

In response to the receipt of a positive response to the authentication request at step 245, the MSC/VLR 2 obtains current data relating to the subscriber from the HLR 12 by transmitting a data obtain signaling message to the HLR 12 at step 250. The data obtain signaling message may be transmitted via the mapping network node 15 if it is provided in the network. An example of such a data obtain signaling message is a MAP Restore Data message.

The HLR 12 provides current subscriber data, in particular the global title of the subscriber's HLR, at step 255 to the MSC/VLR 2 in response to the receipt of the data obtain signaling message. The provision of current data is preferably achieved by transmitting a data insert signaling message. The data insert signaling message can be transmitted via the mapping network node 15 if it is provided in the network. An example of such a data insert signaling message is a MAP Insert Subscriber Data message. The MSC/VLR 2 is updated at step 260, after obtaining current data relating to the subscriber from the HLR 12. Normal network services can thereafter be provided to the subscriber. In an alternative embodiment, the third message transmitted at step 230 is a write data message. An example of such a third message is a message resembling a location update normally transmitted from a MS to a network operations database, e.g. a VLR. The MSC/VLR 2 then sends a data obtain signaling message to the HLR 12 at step 250. An example of such a data obtain signaling message is a MAP Location Update message. As a result, subscriber data, in particular the global title of the subscriber's HLR 12, is provided to the VLR in a data insert signaling message from the HLR to the MSC/VLR 2 at step 255. An example of such a data insert signaling message is a MAP Insert Subscriber Data message. Again authentication can be performed at steps 240 and 245 before the MSC/VLR 2 sending a data obtain signaling message to the HLR at step 250 as discussed above.

Figure 7 illustrates another embodiment of the present invention for updating a MSC/VLR with data from a HLR for a subscriber so as to switch serving MSC/VLRs for the subscriber from a MSC/VLR of one network to another MSC/VLR of another network. The embodiment is discussed in relation to HLRs and MSC/VLRs; however it is to be understood that it can be applied to other subscriber databases, network operations nodes, and/or network operations databases of a mobile communications network. For example, another example of a network subscriber database is a HSS. Similarly network operations nodes/databases other than MSC/VLRs such as SGSN may be used instead.

Referring to Fig 7, MSC/VLR 28 of PLMN (public land mobile network) 1 transmits a data update signaling message to the HLR 12 of PLMN2 at step 300, the data update signaling message indicating that the subscriber is currently being served by the MSC/VLR 28. An example of such a data update signaling message is a MAP Update Location message. The transmission of such a data update signaling message to the HLR 12 may be triggered by a MS 8 of PLMN2 entering a location area 26 served by the MSC/VLR 28 of PLMNl and performing a location update with the MSC/VLR 28. The HLR 12, responsive to the receipt of the data update signaling message, the message containing an identifying code and location information for a subscriber, is arranged to determine that the subscriber is being served by a first MSC/VLR 28 of a different network PLMN 1 from that of the HLR 12 at step 305; to correlate location information for the subscriber contained in the message with information contained in the HLR 12 at step 310 so as to identify a second MSC/VLR 2 of the same network as that of the HLR 12, the second MSC/VLR 2 being able to serve the MS 8; and to cause the second MSC/VLR 2 to obtain current data relating to the subscriber from the HLR 12.

The correlation step may be performed by a correlation function within the HLR 12 or otherwise linked to the HLR 12. The correlation step may comprise: comparing the location information for the subscriber contained in the message with location information for subscribers contained in a table in the HLR to determine a location area 32 of PLMN2, wherein the MS 8 is preferably within the location area 32 of PLMN2; and determining the identity of the MSC/VLR 2 serving the location area 32, the location area 32 may at least partially overlap with the location area 26 of PLMNl.

It is thus established at the HLR 12, that at least some current data relating to the subscriber is not available in the MSC/VLR 2, since the subscriber is being served by a different MSC/VLR 28. It is then established at a first network node 22, separate from the MSC/VLR 2, that at least some current data relating to the subscriber is not available in the MSC/VLR 2.

The HLR may transmit information relating to the subscriber to an IT provisioning system 16 at step 315, the information including an identifying code for the subscriber and an identity for a MSC/VLR 2. The IT provision system 16, in response to the receipt of the information, is arranged to transmit the information to a first network node 22 at step 320. This information is provided to the first network node 22 so that the identifying code for the subscriber can be provided to the MSC/VLR 2 at step 325. The IT provisioning system 16 is not necessary for this embodiment and the information relating to the subscriber can be transmitted to the first network node 22 directly. The first network node 22 may be a message processing node.

Responsive to the receipt of an identifying code for a subscriber and a MSC/VLR identity, it is arranged to transmit a message to the MSC/VLR 2 providing the MSC/VLR 2 with the identifying code such that the MSC/VLR 2 is caused to obtain current data relating to the subscriber from a HLR 12. The message may be a data access signaling message, the data access signaling message including an identifying code for the subscriber, the data access signaling message being of a type as described above. In this embodiment of the invention, the data access signaling message is a MAP Provide Roaming Number message. In response to the receipt of the data access signaling message, it is determined at the MSC/VLR 2 that current data relating to the subscriber is not available in the MSC/VLR 2 at step 330; and in response to the determining, the MSC/VLR 2 obtains current data relating to the subscriber from the HLR 12. Before the MSC/VLR 2 obtains current data relating to the subscriber from the HLR 12, the MSC/VLR 2 may transmit a request authentication signaling message to the HLR 12 at step 335. An example of such a request authentication signaling message is a MAP Send Authentication Request message. A request authentication result signaling message may then be transmitted from the HLR 12 to the MSC/VLR 2 at step 340. An example of such a request authentication result signaling message is a MAP Send Authentication Response message. An alternative action to authentication is ciphering setting.

In response to the receipt of a positive response to the authentication request, the MSC/VLR 2 obtains current data relating to the subscriber from the HLR 12 by transmitting a data obtain signaling message to the HLR 12 at step 345. In this embodiment of the invention, the data obtain signaling message is a MAP Restore Data message. Data obtain signaling messages as well as request authentication signaling messages and request authentication result signaling messages may be transmitted via a mapping network node 15 (not shown) if it is provided in the system. The HLR 12 provides current subscriber data to the MSC/VLR 2 at step

350 in response to the receipt of the data obtain signaling message. The provision of current data is preferably achieved by transmitting a data insert signaling message. The data insert signaling message may be transmitted via the mapping network node 15 (not shown) if it is provided in the system. An example of such a data insert signaling message is a MAP Insert Subscriber Data message.

The MSC/VLR 2 is updated at step 355, after obtaining current data relating to the subscriber from the HLR 12. The MSC/VLR 2 then contacts the MS 8 so as to provide service to the MS 8 at step 360. The MSC/VLR 2 has no valid LAI information for the MS 8 before successful establishment of the first authenticated radio contact. The MSC may be instructed by the HLR to send a signaling message, for example a MAP Send Info for Incoming Call message or a MAP Send Info for MT SMS message, to the VLR. Upon receipt of such a message from the MSC for an MS whose subscriber data are marked as "Confirmed" by the indicator "Confirmed by HLR" but not confirmed by radio contact, the VLR invokes a "MAP Search for MS". Alternatively paging may be used to establish contact with the MS 6.

In the above embodiments, the network operations node requires no alternation in its functionality, compared to a standard implementation. Alternatively the network operations database, for example a VLR, can be reprogrammed or provided originally so that responsive to the receipt of a data refresh request signaling message, it obtains subscriber data from a subscriber database, for example a HLR, regardless whether at least some current data relating to the subscriber is available in the network operations database. The above embodiments are to be understood as illustrative examples of the invention. Further embodiments of the invention are envisaged. For example, other types of signaling messages such as Bearer Independent Call

Control (BICC) and Session Initiation Protocol (SIP) messages can be used instead of MAP messages.

In the embodiments of the invention discussed above, there is provided one signaling message in each signaling message transmission step. However, it is to be understood that more than one signaling message may be transmitted in any of the steps.

A mapping network node 15, though preferred is not necessary for the invention. Data and messages can be transmitted to the second HLR directly from the IT provisioning system, the IT provisioning system having information of the identity of the second HLR. Data and messages can also be transmitted to the second HLR directly from the MSC/VLR, for example if the MSC/VLR is provided with the identity of the second HLR.

An IT provisioning system 16, though preferred in at least some embodiments is not necessary for the invention. The IT provisioning system, if present, can be implemented as part of the first HLR or another existing network node.

A dedicated first network node 22 is not necessary for the present invention, although it is desirable. Its function can be performed by an existing network node, such as a HLR or SLR of the mobile telecommunications system.

If for example the HLR 12 comprises the first network node 22, the HLR can be re-programmed to transmit a signaling message to the MSC/VLR providing the

MSC/VLR with an identifying code for a subscriber and a rule that causes the

MSC/VLR to obtain current data relating to the subscriber from the HLR 12, in response to establishing at the HLR 12 that at least some current data relating to the subscriber is not available in the MSC/VLR. The message may be a data access signaling message as discussed above.

A second network node 34 can be an administrative node or a customer service node. Though preferred, a second network node 34 is not necessary for the invention. Instructions can alternatively be provided to the IT provisioning system manually at the IT provisioning system 16. In the embodiments of the invention the network operations node is MSC and the network operations database is VLR and the MSC and the VLR are implemented as one single network node. However it is to be understood that the network operations database, e.g. a VLR, can be implemented on a separate network node as that for the network operations node, e.g. a MSC, and in that case signaling messages can be transmitted to and from the node hosting the network operations database directly or to the network operations node which will then access data in the network operations database via a communications link. A network operations node for the purpose of the invention can be a VLR, a MSC or a MSC/VLR while a network operations database can be a VLR.

It is to be understood that any feature described in relation to any one embodiment may be used alone, or in combination with other features described, and may also be used in combination with one or more features of any other of the embodiments, or any combination of any other of the embodiments. Furthermore, equivalents and modifications not described above may also be employed without departing from the scope of the invention, which is defined in the accompanying claims.

Claims

1. In a mobile communications network, a method for updating a network operations database with data from a subscriber database for a subscriber, the method comprising: establishing at a first network node, separate from a network operations node, that at least some current data relating to the subscriber is not available in the network operations database; and in response to said establishing, initiating the transmission of a data access signaling message to the network operations node, the data access signaling message including an identifying code for the subscriber, the data access signaling message being of a type which causes the network operations node: a) to attempt to access current data for the subscriber in the network operations database; and b) if the at least some current data relating to the subscriber is not available in the network operations database, to obtain current data relating to the subscriber from the subscriber database.

2. A method according to claim 1, wherein said data access signaling message is a MAP Provide Roaming Number message.

3. A method according to claim 1 or 2, comprising, at the network operations node: in response to receiving said data access signaling message, determining that at least some current data relating to the subscriber is not available in the network operations database; and in response to said determining, obtaining current data relating to the subscriber from the subscriber database.

4. A method according to any preceding claim, wherein the network operations node obtains current data from the subscriber database by transmitting a data obtain signaling message to the subscriber database.

5. A method according to claim 4, wherein said data obtain signaling message is a MAP Restore Data message.

6. A method according to any preceding claim, wherein said establishing comprises: transmitting a data deletion signaling message to the network operations node, thereby causing deletion of at least some current data relating to the subscriber from the network operations database.

7. A method according to claim 6, wherein said data deletion signaling message is a MAP Cancel Location message.

8. A method according to any preceding claim, comprising transferring responsibility of storing data relating to a subscriber from a first subscriber database to a second subscriber database, prior to the network operations node obtaining the data from the second subscriber database for the subscriber.

9. A method according to claim 8, comprising updating a mapping network node, the mapping network node providing a service for mapping a subscriber identity code to a subscriber database identity, the updating of the mapping network node comprising updating the subscriber database identity mapped for the subscriber from an identity for the first subscriber database to an identity for the second subscriber database, prior to the network operations node obtaining the data from the second subscriber database for the subscriber.

10. A method according to any of claims 1 to 5, wherein said establishing comprises: receiving a data update signaling message, said data update signaling message indicating that the subscriber is currently being served by a different network operations node.

11. A method according to claim 10, wherein said data update signaling message is a MAP Update Location message.

12. A method according to any preceding claim, wherein said subscriber database is a home location register (HLR) or a home subscriber server (HSS) and said network operations database is a visitor location register (VLR).

13. A mobile communications network arranged to conduct the method of any preceding claim.

14. A message processing system, responsive to the receipt of an identifying code for a subscriber, and a network operations database identity, arranged to transmit a first message to a network operations node thereby causing deletion of at least some current data relating to the subscriber from the network operations database; and, responsive to the receipt of a second message indicating the completion of said deletion, to initiate the transmission of a third message to the network operations node providing the network operations node with the identifying code for the subscriber such that the network operations node is caused to obtain current data relating to the subscriber from a subscriber database.

15. In a mobile communications network, a method for subscriber migration from a first subscriber database to a second subscriber database, the method comprising:

1) transferring responsibility of storing data relating to a subscriber from the first subscriber database to the second subscriber database; and 2) in response to confirmation that the second subscriber database has assumed responsibility, triggering a network operations node to refresh subscriber data from the second subscriber database by sending a data obtain message.