GB2440989A

GB2440989A - Network service provision in a mobile communication system

Info

Publication number: GB2440989A
Application number: GB0619849A
Authority: GB
Inventors: Craig Bishop; Chen Ho Chin; Eanny Bae
Original assignee: Samsung Electronics Co Ltd
Current assignee: Samsung Electronics Co Ltd
Priority date: 2006-08-18
Filing date: 2006-10-06
Publication date: 2008-02-20
Anticipated expiration: 2026-10-06
Also published as: GB2440987A; GB0616513D0; GB2440989B; GB0619849D0

Abstract

A method of providing network services in relation to a call, for use in mobile communications network (100) including a circuit switch (CS) domain, an IP multimedia subsystem (IMS), and a first network element (102), where the method includes modifying at least one of the network services in the IMS in response to a request message in relation to the call received at the first network element (102), for switching the call from one of the network domains to the other. For example, if a subscriber moves domains during a call, services such as call barring in the new domain may be disabled or not invoked as the checks may have already been carried out. Call barring services may be synchronized between IMS and CS domains.

Description

* 2440989

MOBILE COMMUNICATION

FIELD OF THE INVENTION

The present invention relates to mobile communications systems and in particular to providing network services in a mobile communications system including an IP network including an IP Multimedia Subsystem (IMS) and a circuit switch (CS) domain. More particularly, the invention relates to providing network services when a user's or subscriber's call is switched from one of the network domains to the other, i.e. from the IMS to the CS domain, or vice versa.

BACKGROUND

There are a myriad of network services available to subscribers of mobile communications networks, for example Call Barring Services. Call Barring Services can be provisioned either as Operator Detennined Barring or user controlled Supplementary Services Call Barring. They include but are not limited to, Barring of All Outgoing Calls (BAOC), Barring of Outgoing International Calls (BOIC) and Barring of Outgoing International Calls except Home Public Land Mobile Network (BOIC-exH).

An example of 0DB is when a pre-paid customer or subscriber might have used up all his paid up credit. So the operator can determine that all outgoing calls are barred (BAOC) except for some special dialled numbers eg. to customer services to buy more credit. In BOIC, a customer may decide "as a parent I do not want my children to make any international calls that incur international call rates that I do not want ". So for many subscribers unaware of (and who do not want) huge international roaming charges, they can set up BOIC as part of their Call Barring Services.

In addition, an example of BOIC-exH can be when a customer decides "as a parent I do not want my children to make any international calls, but as he is travelling abroad I would like that he can call home (f only to his house)" or they may decide "While roaming I do not want incoming calls made to my home to be diverted to me incurring international roaming charges. But I still wish to get my voicemail at home ". So they may set up BOIC-exH as part of their call barring service.

This can get more complicated when the user equipment or subscriber needs to transfer a call from the IP Multimedia Subsystem (IMS) to the Circuit Switched (CS) domain, or vice versa. A brief outline of the pertinent functions is now given in this respect. There are numerous mechanisms for anchoring calls in the IP Multimedia Subsystem (IMS) in order to enable Voice Call Continuity (VCC) procedures to transfer calls between the CS domain and the 1MS and vice-versa. One of these mechanisms uses the Customised Application for Mobile Enhanced Logic (CAMEL) triggers at the Visitor Mobile Switching Centre (VMSC) network entry in the Visited Network to re-route a call originated in the CS domain to the IMS for anchoring in the IMS. In that case it is possible to anchor calls even if the user equipment (UE) is not IMS registered at the time of call origination.

Alternatively, the UE may be IMS registered and the call is anchored directly in the IMS within the UE Home Network using initial Filter Criteria to invoke the VCC Application Server when the mobile makes an IMS type call.

A subscriber uses UE such as a mobile terminal (also known as a terminal), a mobile terminal with a Subscriber Identity Module (SIM) or Universal SIM (USIM) or UICC, a computer terminal, PDA, or any other form of equipment capable of being used in a communication network including the CS domain and IMS. In addition, term subscribers or users may be used interchangeably.

The VCC Application is typically a home IMS application providing capabilities to transfer voice calls between the Cs domain and the IMS. The VCC Application also provides functions for voice call originations, voice call terminations and for domain transfers between the IMS and the CS domain and vice versa. Figure 1 illustrates the VCC Reference Architecture of the VCC Application and further details of this reference model can be found in "3GPP TS 23.206 V1.2.1 Voice Call Continuity, Stage 2".

Referring to Figure 2 a message flow for CS originated VCC calls is illustrated. There are various entities, or network elements, involved in the establishment of a CS originated call that is re-routed the subscriber's home IMS network for anchoring. The UE (CS and IMS parts) located in the Visited Network, which also includes the VMSC network element. The network entities (or elements) in the UE Home Network include the Media Gateway Control Function (MGCF), Interrogating Call Session Control Function (I-CSCF), S-CSCF (Serving CSF), GSM Service Control Function (gsmSCF), and the VCC Application. The VCC Application includes the CAMEL Service, Circuit Switched Adaptation Function (CSAF) and the Domain Transfer Function (DTF).

A pertinent portion of the message flow is described as follows: 1. The VCC user (Party A) originates a voice call to Party B in the CS domain using a VCC equipped UE. That is the UE sends a SETUP message containing the Party B DN to the VMSC.

2. Origination triggers at the VMSC are detected; VMSC sends an Initial Detection Point (InitialDP or IDP) message towards the gsmSCF.

3. The gsmSCF invokes the VCC Application's CAMEL Service, which determines that the call needs to be rerouted, i.e. switched, to IMS for VCC; thus, the CAMEL Service reroutes the call to the IMS by allocating an IP Multimedia Routing Number (IMRN) and returning it to the gsmSCF; otherwise it responds with a CAMEL Application Protocol (CAP) Continue.

Note: How the information available to the CAMEL Service is used to decide whether the call should be routed through the IMS is implementation specific and not standardized in this specification.

The interface between the gsmSCF and the CAMEL Service is unspecified.

4. The gsmSCF responds with a CAP Connect message containing the Original Called party ID and Destination Routing Address. The Destination Routing Address contains the IMRN to route the call to the CSAF. Handling of Destination Routing Address and Original Called party ID is as defined in "Technical SpecfIcation 23.078 Customised Applications for Mobile Network Enhanced Logic (CAMEL) Phase 2".

5. The VMSC routes the call towards the user's home IMS network using the IMRN via a MGCF in the home network.

6. The MGCF initiates an iNVITE message towards the I-CSCF in the home IMS of the originating VCC user. The calling party number and/or original called number are included in the INVITE if they are received from the PSTN call setup signalling (e.g., ISUP).

7. The I-CSCF routes the INVITE based on one of the following standard procedures specified in "Public Service Identity (PSI) based Application Server termination -direct and PSI based Application Server termination -indirect" procedures outlined in "Technical Specification Group Services and System Aspects 23.228, IP Multimedia Subsystem (IMS), Stage 2" (IS 23.228) 7a. The I-CSCF forwards the INVITE to the CSAF via the S-CSCF that is assigned to the IMRN; or 7b. The I-CSCF forwards the INVITE directly to the CSAF.

8. If, when the INVITE arrives at the VCC Application, it is processed by the CSAF of the VCC Application, which may use the IMRN to

S

retrieve the original called party number and the calling party number from the CAMEL Service. The CSAF uses the original called number and the calling party number to setup the outgoing call leg to party-B in accordance with the Access Stratum (AS) origination procedure as defined in clause 5.6.5 of TS 23.228.

9. The DTF of the VCC Application anchors the originating session for enablement of domain transfers for the session as part of this procedure based on operator policy.

Note: Steps 8 and 9 may comprise of a sequence of messages for communication to/from different VCC Functional Elements.

10. The DTF sends the INVITE back to the S-CSCF for completion of the call toward the remote end.

Standard originating call setup procedures as per TS 23.228 are followed to continue the call setup at the S-CSCF for the VCC user The following is a brief description of CAMEL's Onginating-BSCM (0-BSCM) interacting with VCC functionalities. The O-BSCM for CAMEL Phase 2 (CAMEL2) is illustrated in Figure 3. Notes 1 & 3 on the figure show at which point in the O-BSCM Call Barring is applied. Note 2 shows at which 0-CS! triggers send InitialDP towards the gsmSCF i.e. the VCC Application.

Operator Determined Barring (0DB) and Supplementary Service Barring of All Outgoing Calls (BAOC) are checked and invoked prior to Detection Point 2 (DP2) as necessary (see note 1). This call barring therefore acts upon all CS originated calls regardless of whether the call is a domain transfer request using the VCC domain transfer number. If there is no coordination between CS and IMS in respect of Barring of All Outgoing Calls (BAOC), domain transfer may fail leading to a poor user experience. This may not be considered a problem in the case of Mobile Originated calls for which domain transfer to the CS domain is requested, as subscribers home network operator may choose to maintain different Call Barring settings for the CS domain and the ilvIS due to there being different costs associated with calls established in the CS domain and sessions established in the IMS. However, in the case where the UE is the recipient of a Mobile Terminated IMS session, a subsequent domain transfer request to the CS domain should not be considered an outgoing call and should therefore not be subjected to outgoing call barring.

Operator Determined and Supplementary Service Barring of Outgoing International Calls (BOIC) and Barring of Outgoing International Calls except those to the Home Public Location Mobile Network (HPLMN) (BOIC-exH) are checked and invoked after InitialDP triggering at DP2 as necessary (see note 3). This call barring acts dependent on the Called Party Number, which by this time will have been replaced by the IMRN in the CONNECT message returned by the gsmSCF.

Domain Transfer from CS domain to IMS Figure 4 illustrates the signalling flow of the signalling involved in performing a domain transfer from CS domain to IMS. This particular example flow illustrates the use of CAMEL to resolve the VDN into a routable number, so that the call can be routed to the VCC Application where a 3 party call control (3pcc) B2BUA call can be initiated by the VCC Application. Other methods to resolve the VDN are not discounted and one option would be to use VDN that area selected from a range of numbers not subject to CAMEL processing, but that directly address the VCC Application.

The provision and use of VDNs is being worked on by both 3GPP TSG SA WG2 and 3GPP TSG CT WG1. The latest details can be found in versions of TS 23.206 1.2.1 (Stage 2) and TS 24.206 0.7.1 (Stage 3).

The following references provide further information on the network architecture, General Packet Radio Service (GPRS), which are described in: Technical Specification "3GPP TS 23.002 v6.10.0 -Network Architecture ", Technical Specification "3GPP TS 23.060 v6. 11.0 -General Packet Radio Service (GPRS); Service description; Stage 2", UK Patent Application GB 0602266.9, filing date 03 February 2006, entitled "Mobile Communications" assigned to the present applicant and incorporated herein by reference, UK Patent Application GB 0612129.7, filing date 19 June 2006, entitled "Mobile Communications" assigned to the present applicant and incorporated herein by reference, and Technical Specification "3GPP TS 23.0 78 -Customised Applications for Mobile network Enhanced Logic (CAMEL) Phase 2".

Referring again to Figure 3, a short condensed view of how CAMEL 2 (CAMEL Phase 2) State Control Machine (of the Visited Network) triggers back to the Home Public Land Mobile Network (HPLMN) is illustrated.

From the Figure one can see that the CAMEL trigger points DP acting on the Dialled Numbers take place before and after DP2 and that DP2 is the trigger point where through Initial DP the VCC application (along with the gsmSCF) is contacted as described previously.

When the CONNECT message comes back from the VCC Application with an 1MRN, that IMRN will be worked on by the O-BSCM. As a result of this, the following issues can arise:- 1. International calls originating in HPLMN could be successful even though BOIC or BOIC-exH was set, because BOIC would act on the IMRN, which would be an HPLMN number.

2. Local calls made when roaming could fail if BOIC was set, because IMRN would be considered as an international call in the O-BSCM.

3. Domain transfer when roaming could fail if BOIC was set, because VDN and/or IMRN would be considered as an international call in the O-BSCM.

For sessions originated in the IMS, the Telephony Application Server (TAS), which is an Application Server (AS) that serves a telephony function, implementing the OCB service should be included after the AS implements the VCC Application. As such, the Called Party identifier of the intended destination e.g. Session Initiated Protocol Uniform Resource Identifier (SIP URI) will be the number that is acted upon by OCB. In the case of domain transfer from the CS to the ilviS using VCC Domain Transfer URI, this too will be resolved at the VCC Application before Call Barring is applied at the TAS.

Further Examples of Call Barring service failures BOIC set for a roaming VCC users BOIC is set for CS domain. In the O-BCSM, BOIC is not checked/invoked until after the Called Party Number has been replaced by the IMRN. When UE-A is roaming and places a call towards a local UE-B, the Called Party Number is replaced with the IMRN towards its home IMS. This is considered by the VMSC to be an international number, so the call is barred even though it was not an international call. To avoid this situation, Call Barring Services for the user would have to be centralised in the IMS and invoked once the IMRN had been replaced with the Called Party Number in the home IMS (taking into account the location of UE-A). In addition, the CS Call Barring service BOIC would have to be disabled to enable the call to progress. This may also result in a call failure when transferring back to the CS domain from the IMS.

Disable Call Barring Services for calls that are not anchored It may be proclaimed that a quick and easy solution is to generally disable CS Call Barring Services for VCC subscribers. But the problem is that the decision to anchor or not anchor a call can be more dynamic than just based on a VCC subscription.

Take the example of a VCC subscriber (UE-A of Belgium) who has BOIC.

So to overcome the problem described CS Call Barring Services are disabled.

UE-A when roaming in UK, makes an international call towards UE-B of Germany. For whatever reason (location of UE-A, non-availability of CAMEL in local network, etc) the call from UE-A is not re-routed towards the home IMS for anchoring. The call remains in the CS domain and the BOIC Call Barring Services are not checked/invoked. The international call is not barred even though BOIC was set.

Other Issues In addition, domain transfers from the IMS to the CS domain, in which calls originated in the CS domain but have been subsequently transferred to the IMS, may fail. This is because once a call is in the IMS the previous CS connection is no longer active. If a domain transfer is subsequently requested the VDN will be subject to the same Call Barring checking or different set of Call Barring Services in the CS domain as a number dialled as part of normal call establishment. Thus a call may fail due to incompatible call barring services, even though the call has been allowed to proceed in the IMS. This problem would also arise for calls established (anchored) in the IMS for which domain transfer to the CS domain is subsequently requested.

Furthermore, depending on implementation, it may be that domain transfer requests towards the VDN are not subject to CAMEL call processing so there would be no indication that the call is anchored in the IMS. This may be due to efficient signalling including the VDN as one of a small range of numbers that are not subject to CAMEL service triggering. In this case, it may not be possible to use gsmSCF to disable CS call barring in which case BOIC may be invoked unnecessarily, e.g. the VMSC will check the Call Barring Services in relation to the call, even though these have already been checked at the time of initial call establishment. As a result, domain transfers may then be delayed or inadvertently fail.

Further, if BOAC is set in the CS domain for all outgoing calls and the operator does not wish to synchronise Call Barring services between the CS domain and the IMS, any domain transfer request will fail even if the call was originally terminated towards the UE.

There are significant problems with the current implementation of network services, as shown in the examples above in relation to Call Barring Services in both the IMS and CS domains. This may result in subscribers not being able to use the Call Barring Services and other invoked network services to their full advantage. The Applicant notes that currently there is no control in the way Call Barring Services are implemented in the core network, let alone the CS domain and IMS. The Applicant has thus perceived the need of improving the integration of network services, such as Call Barring Services, between the CS and IMS or IMS and CS domains, to reduce the increasing likelihood of the above identified problems from occurring.

SUMMARY OF THE INVENTION

The Applicant has found that to overcome the above-mentioned problems, in particular the problem of correctly and efficiently applying, modif'ing or using invoked network services in each domain or subsystem when a call is switched from one domain to the other (i.e. when a call is anchored in the IMS or CS domain or during call anchoring in the IMS), where at least one of the network elements is capable of performing the switch between domains in relation to the call, based on the invoked network services and processing the call accordingly. In order for the call to be processed accordingly, these network services in relation to the call may require modification such as suspension and/or synchronisation.

The Applicant has realised that domain transfers (one of the ways of switching a call between domains e.g. between IMS and CS domain or CS domain and IMS) and hence proper call processing, can be triggered by either an explicit indication or an implicit indication to allow or modify the various network services, in relation to the call, to be applied appropriately and only when necessary. For example, if a domain transfer is detected by a network element through the indication, then the network element may modify some network services, such as Call Barring Services, i.e. disable or suspend Call Barring Services, such that the required Call Barring Service checks are not performed as these have already been carried out on call origination from CS to IMS and/or call origination in the IMS and/or call anchoring in the IMS, and thus the network element proceeds to process the call and switch or transfer domains if appropriate.

Additionally, even if Call Barring Services are to be centralised in the IMS, the Applicant has realised that should Call Barring Services be active in the CS domain, these are not known to the IMS and the IMS would be unable to deliver those subscribed to Call Barring Services once the CS domain originated call gets anchored in the IMS. It is also not so much whether Call Barnng Services are to be centralised for VCC, but rather the Applicant has realised that when Call Barring Services are centralised the Call Barring Service settings in the IMS should then be modified i.e. they can be synchronised between the CS domain and the IMS.

Furthermore, the Applicant has realised, that if IMS Call Barring Service settings are not modified to be synchronised with CS Call Barring Service settings, then in a domain transfer of an ongoing CS call from the CS domain to IMS or vice versa, the domain transfer or the call could fail if there is a misalignment between domains.

The Applicant has realised that in order for network services to be modified, by synchronisation and domain transfers, this modification can be triggered by either an explicit indication or implicit indication to allow the correct application of network services in relation to the call, whether it be call anchoring or domain transfers. Following the synchronisation, the Call Barring Services can be handled and provided for in the IMS for the duration of that call, and, when the network entities are modified according to the aspects of the Invention, even after one or more domain transfers, while the Call Barring Services for that subscriber are suspended in the CS domain.

The term "switching" in this specification refers to the functions or operations of routing, transferring, or moving a call from one domain to the other domain, i.e. from the IMS to the CS domain or from the CS domain to the IMS. For example a call can be switched from the CS domain to the IMS when the call is to be handled or is handled and anchored in the IMS.

Similarly, this applies for a call being switched from the IMS to the CS domain.

In one aspect, the invention relates to a method of providing network services to one or more users (or subscribers) in relation to a call in a communications network including a circuit switch (CS) domain, an IP multimedia subsystem (IMS), and a first network element, the method comprising modifying at least one of the network services in the IMS in response to a request message in relation to the call, received at the first network element, for switching the call from one of the network domains to the other.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred features and embodiments of the invention will now be described, purely by way of example, with reference to the accompanying drawings, in which: -Figure 1 illustrates a portion of the VCC Application VCC Reference Architecture Figure 2 illustrates the message flow for CS domain originated VCC calls.

Figure 3 illustrates the structure of the Originating BSCM for CAMEL.

Figure 4 illustrates a domain transfer from CS domain to IMS.

Figure 5 illustrates a communications system for use by the embodiments of the invention.

Figure 6 illustrates the logic flow of a preferred embodiment of the invention.

Figure 7 illustrates the message flow of a preferred embodiment of the invention in which the UE invokes a domain transfer.

Figure 8 illustrates further communications system for use by the embodiments of another aspect of the invention.

Figure 9 illustrates the logic flow of a preferred embodiment of the aspect of the invention of Figure 7.

Figure 10 illustrates the message flow of a preferred embodiment of the invention in which the VCC Application informs HSS (through Sh interface).

Figure 11 illustrates the message flow of an embodiment of the invention in which VMSC/VLR acts on an explicit indication signal in the CONNECT message.

Figure 12 illustrates the message flow of another embodiment of the invention in which VMSC/VLR acts on an explicit indication of type of Called Party Number.

Figure 13 illustrates the message flow of a further embodiment of the invention in which VMSC/VLR makes an implicit determination.

Figure 14 illustrates the message flow of a embodiment of the invention in which the UE provides an indication of call anchoring to the VMSC/VLR.

Figure 15 illustrates the message flow of another embodiment of the invention in which the VMSC/VLR processes the returned original Called Party Number.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Firstly, a description is given for a simplified communication system for use in providing network services to subscribers. This is followed by a description of the preferred embodiments of providing network services where appropriate in relation to, but not limited to, network services, invoked network services, and invoked network services such as Call Barring Services.

C

An illustration of a simple communication system is given in Figure 5.

Referring to Figure 5, the communications system includes a communications network 100, which includes a circuit switched (CS) domain and an IP Multimedia Subsystem (IMS). These are able to exchange infonnation with a first network element 102 via communications interface 108.

The communication interface can be physical or wireless interfaces for exchanging information. Examples of such interfaces or forms of exchanging information are found in the above-mentioned references. The communications system also includes a first user equipment 11 2a being used by a first subscriber 11 2b and a second user equipment 11 4a being used by a second subscriber I 14b. These subscribers are possibly communicating over or with the communication network 100 via a wireless connection indicated by the arrows.

Referring to Figure 5, network services are provided to at least one of the subscribers (1 12b or I 14b) in the communications network 100. The first subscriber 11 2b initiates a call on the first user equipment 11 2a to the second subscriber 1 14b on the second user equipment 1 14a. A call from one of the subscribers (1 12b or 1 14b) may be handled and finally anchored in the IMS.

This is advantageous as consider processing and handling the call in the IMS can allow subscribers (1 12b or 1 14b) to take full advantage of additional network services that the IMS provides including providing an improved quality of service and user experience.

The network services that are used by the subscribers (11 2b and 11 4b) are called invoked network services. These are network services the subscribers (112b and I 14b) have set up on their subscription with the network provider or on their user equipments (1 12a and/or 1 14a), which are invoked when they use their user equipments (1 12a and/or 1 14a) to conmiunicate over the communications network 100.

C

The invoked network services can include Call Bathng Services, Supplementary Services, Call/Hold and Transfer Services, Conference Call Services, Multiparty Call Services, Malicious Call Services and other useful network services arid the like that subscribers (11 2b and/or 11 4b) or network providers may need implemented in the future on the communications network 100.

If the call is handled in the IMS, then the call handling in the IMS includes anchoring the call in the IMS. More specifically, the first network element 102 may have functionality in which to handle the call and/or also further functionality to proceed with anchoring the call in the IMS, i.e. either by itself with through additional network entities (not shown). If a call originated in the CS domain, then it can be handled by the first network element 102 and finally anchored in the IMS.

As will be discussed below, network services do not have to be synchronised between the CS domain and the IMS, although some embodiments may require synchronisation of services. Other embodiments, which are also discussed below, may use for example an explicit domain transfer indication in the set up or request message providing the advantage of not requiring synchronisation of network services. The invention is not limited to requiring synchronisation between the CS domain and IMS.

Network services can be modified in many ways i.e. they can besynchronised between the CS domain and the IMS once the decision is taken in the first network element 102 to handle the CS domain originated call in the IMS, or they can be suspended in full or in part in the CS domain or IMS to provide the appropriate network services at the right time to the subscribers and users of the communications system.

C

Once a call has been anchored in the IMS, the call proceeds and both parties communicate with each other, i.e. the first subscriber 11 2b may have called the second subscriber 11 4b and are now communicating with each other using services provided for in the IMS. During the call, the first or second subscribers 11 2b or 11 4b may perform a domain transfer depending on their location, the network services or applications they have chosen to use and the like. For example, the subscribers 11 2b or 11 4b may each have moved into a network area that does not support the IMS or they are using network services that do not require the support of the IMS, hence one of the subscribers 11 2b or 1 14b may perform a domain transfer, i.e. switch domains, into the CS domain to continue the call accordingly.

In order to alleviate the problems described above, i.e. to prevent the possibility of the call failing, the first or second subscriber 11 2b or 11 4b may send an indication to the first network element that a domain transfer is taking place. According to the preferred embodiments of the invention as described the first network element 104 can be modified to recognise the situation, which will now be described below.

The subscriber's (112b, 114b) user equipment (112a, 114a) is aware" that a domain transfer is required, since they should have the required hardware/software to perform the domain transfer according to the network services, service or applications, the subscribers (1 12b, 1 14b) are using. This awareness allows the user equipment (1 12a, I 14a) to trigger by either an explicit indication signal or an implicit indication signal, the first network element 102 that a domain transfer is taking place. The domain transfer is usually requested by one of the user equipments 11 2a or 11 4a. By embedding an explicit or implicit indication signal into the request, the first network element 102 can recognise that certain network services do not need to be invoked, checked or processed, i.e. by modifying at least one network service.

As the first network element 102 detects the domain transfer request, it then performs procedures depending on the network services invoked during the call. If Call Barring Services have been invoked during call origination then the call has already been checked to make sure it satisfies either subscribers 1 12b or I 14b Call Barring Service settings etc., thus the first network element 102 may modify the Call Barring Services by suspending them as the first network element 102 does not need to check the Call Barring Services on proceeding with a domain transfer from the IMS to the CS domain.

Similar procedures may be performed for other invoked network services depending on the type of invoked network service, thus by modifying them or their behaviour, the first network element can ensure correct transfers or switching of the call from on domain to the other. Thus by performing the domain transfer in this way, the first network element in the IMS has prevented the unnecessary checking and processing of the Call Barring Services in relation to the call, by modifying these services through suspension of the service. In a large user environment this will reduce the processing load, the messaging load between network entities and thus improve the throughput of the communication network 100. In addition, there would be a decrease in call failures in cases where the invoked network services are different in each of the domains and in the situation when these have not been synchronised, as may happen in a call originated directly in the IMS.

In some preferred embodiments the indication signal sent by the user equipment 112a or 114a includes an indication of domain transfer. This allows the first network element 102 to either modify or set the network services such that they are disabled or suspended to prevent checking and processing the call with these network services enabled, i.e. the first network element 102 can disable checking of Call Barring Services between the IMS and CS domains, since these have already been checked as the call is still ongoing. But, if the user equipment does not specify that the request for transfer is domain transfer, the first network element 102 may consider the call transfer as a originating call and/or if the domain transfer is not detected then the processing of the call may occur in the usual manner, i.e. Call Barring Services will be processed and checked in relation to the call before the transfer to the CS domain occurs.

A domain transfer may not be detected, depending on the implementation of the communication network 100, when domain transfer requests towards the VDN are not subject to CAMEL call processing, hence there is no indication to the first network element 102 in any CONNECT message that the call was anchored in the IMS (no CONNECT message is sent). This may be because the network entities may consider signalling to be more efficient to include the VDN as one or a small range of numbers that are not subject to CAMEL service triggering. Hence, having the subscriber, users or user equipment send an indication to the first network element 102 ensures that these entities know a domain transfer is taking place, and that the user equipment 11 2a or 1 14b has been anchored in the DvIS.

The indication signal can also include a user equipment (1 12a and/or 114a) identification or a second user equipment (1 14a) identification such as a Calling Party identifier. In another embodiment the indication signal includes an indication of a type of destination address or a type of destination number.

These are examples to explicit indication signals for handling the call in the IMS.

There are many network entities that make up the communications network 100, let alone the CS domain and IMS, any other network element may be used to implement the preferred embodiments of the invention. It can be envisaged that other network elements will need to receive the indication signal for notification of the domain transfer in relation to the call and to act accordingly or to notify other network elements accordingly.

The first network element 102 may include storage media for details of at least one roaming user equipment, which could be either the first or second user equipment (1 12a and/or 1 14a) that has roamed into the area that the first network element 102 serves. In other cases, these network entities can be or have the functions of a mobile switching centre.

Referring now to Figure 6, a logic flow of a preferred embodiment of the invention is illustrated in which the UE includes in the SETUP message an indication that call is domain transfer request. In the case of a request for domain transfer using VDN it may be that the request is to be directly routed towards the VCC Application and not require re-routing using CAMEL triggers. In that case there can be no synchronisation indication returned, so in order that Outgoing Call Barring services do not prohibit domain transfer, the UE should provide an indication that the call is a domain transfer request in order that the VMSC can suspend Call Barring checking and invocation in the CS domain, i.e. an indication that Call Barring checking should be suspended is provided to trigger the VMSC to modif' the appropriate network services to ensure Call Barring checking is suspended.

As previously discussed above, it is explained that the suspension of Call Barring services in the CS domain should only be active for as long as the call is active in the CS domain. This introduces a potential problem for calls originated in the CS domain that have been subsequently transferred to the IMS, because once the call is in the IMS the previous CS connection is no longer active. If a domain transfer is subsequently requested to transfer back to the CS domain, i.e. from the above description the call was anchored in the IMS, the VDN will be subject to the same Call Barring checking, or checking in relation to other invoked network services, as a number dialled as part of normal call establishment. This problem also arises for calls established in the IMS for which domain transfer to the CS domain is subsequently requested.

Further, depending on the implementation of the network, it may be that domain transfer requests towards the VDN are not subject to CAMEL call processing so there could be no indication in any CONNECT message that the call was anchored in the IMS, as there would be no CONNECT message sent.

This is because it may be more signalling efficient to include VDN as one of a small range of numbers that are not subject to CAMEL service triggering.

in one of the preferred embodiments of the invention, the UE instead populates the Called Party Number (CPN) Information Element (IE) in the SETUP message with a network provisioned VDN when requesting domain transfer. As the UE is "aware" that the requested call establishment is for a domain transfer, the UE further includes an explicit or implicit indication in the SETUP message sent towards the VMSC network element. This provides an indication to the VMSC network element that the message is also a domain transfer request.

The call processing state machine of VMSC network element or the Visitor Location Register (VLR) network element is modified to check for the indication that the call was a domain transfer request, i.e. a Domain Transfer Request (DTR) indication. Thus, on receiving such a DTR indication, the VMSC network element implements the appropriate procedures to ensure the call is efficiently transferred to the CS domain. In the case of Call Barring Services, the VMSC network element suspends the checking and invocation of the various related network services, i.e. set or modifies the network services in relation to the call, In relation to other invoked network services, the VMSC network element will take appropriate action such the call is successfully transferred to the CS domain improving the users quality of service.

The explicit or implicit indication is included as a modified or new code value for an existing Information Element in the SETUP message sent by the UE towards the VMSC network element. For example, by modifying the Called party Binary Coded Decimal (BCD) number or Called party subaddress IE, or any other of the current lEs in the SETUP message that can be reasonably considered by the VMSC network element during call processing.

Figure 7 illustrates another preferred embodiment of the invention, in which a new Information Element is defined and added to the SETUP message to indicate that it was a request to transfer domains. As described above, different network implementations may result in domain transfer requests failing as the VMSC does not recognise that it is anchored in the IMS. That is the VDN may not be subject to CAMEL call processing so there could be no indication in any CONNECT message that the call was anchored in the IMS, as there would be no CONNECT message sent. This is because it may be more signalling efficient to include VDN as one of a small range of numbers that are not subject to CAMEL service triggering. Hence, the new IE added to the SETUP message by the UE informs the VMSC/VLR that a domain transfer is taking place and thus the VMSC/VLR can take appropriate action as described in this specification -i.e. modifying the network services or the operation of the network services in relation to the call to ensure the call is switched from one domain to the other appropriately.

As an example, when the VMSC network element receives this new Information Element in the SETUP message/request it can take appropriate action to not duplicate the invoked network services, as they have already been invoked, for example in relation to Call Barring Services the VMSC network element modifies these network services by suspending them and

C

thus suspending the checking and invocation of Call Barring Services for the Domain Transfer Request in relation to the subscriber's UE. This has already occurred on call origination from the CS domain to the IMS or from a call origination directly in the IMS, i.e. when the call has been anchored in the IMS. The call is then processed in accordance with a domain transfer request.

In relation to other network services, the VMSC network element will take the appropriate action to ensure the call is processed and transferred correctly and efficiently to the CS domain.

It can be noted that this "DTR" solution can equally apply for Domain Transfer Requests in networks where VDN was subject to CAMEL service triggering.

For the indication that a CS call is a domain transfer request, the indication could differentiate between whether the domain transfer request was for a call that was originally a terminated call to the UE, or an originated call from the UE. This is because network operators and users may wish to maintain different invoked network services, such as different outgoing Call Barring Service settings in the CS domain and the IMS, and because it may be legitimate to bar a domain transfer request to the CS for an MO (Mobile Originated) IMS session for which the originating user pays, where as it would not be acceptable to bar a domain request to the CS for an MT (Mobile Terminated) 1IMS session for which the terminating user is not liable.

Referring now to Figure 8, another embodiment of another aspect of the invention is now described. An illustration of another simple communication system is given in Figure 8. Referring to Figure 8, the communications system includes a communications network 200 includes a circuit switched (CS) domain and an IP Multimedia Subsystem (IMS) domain, which are able to exchange information with a first network element 202 and a second network element 204 via communications interfaces 208 and 210.

First and second network elements 202 and 204 can also exchange information via an additional communication interface 206 with each other.

The communication interfaces can be physical or wireless interfaces for exchanging information. Examples of such interfaces or forms of exchanging information are found in the above-mentioned references. The communications system also includes a first user equipment 212a being used by a first subscriber 212b and a second user equipment 214a being used by a second subscriber 214b. These subscribers are possibly communicating over or with the communication network 200 via a wireless connection indicated by the arrows.

Referring to Figure 8, network services are provided to at least one of the subscribers (212b or 214b) in the communications network 200. The first subscriber 21 2b initiates a call on the first user equipment 21 2a to the second subscriber 21 4b on the second user equipment 21 4a. The communication network 200, which includes the CS domain (or CS network) and the IP Multimedia Subsystem (IMS) domain (or IMS network) call may be processed and handled in the CS domain, depending on the network services the subscribers (212b and 214b) have set-up.

The call handling can include anchoring the call. But, it is advantageous to also consider processing and handling the call in the IMS to allow the network services to take full advantage of the network and provide an improved quality of service and user experience. If the call is handled in the IMS, then the call handling in the IMS can include anchoring the call in the IMS. More specifically, the second network element 204 may have functionality in which to handle the call and/or also further functionality to anchor the call in the IMS.

In order to handle the call, which may have originated in the CS domain, in the IMS the network services are synchronised using the first or second network element 202 between the CS domain and the IMS, once the decision is taken in the second network element 202 to handle the CS domain originated call the IMS.

Synchronisation of the network services is triggered by either an explicit indication signal or an implicit indication signal, which is sent to the first network element 202 for handling at least a portion of the synchronisation of network services between the CS domain and lIvIS. But, the second network element 204 can instead also handle at least a portion of the synchronisation of network services between the CS domain and IMS of the communications network 200. This is only an example, or one of many embodiments of the invention, in relation to providing network services to subscribers of a communications system. The primary focus is on the use of an explicit or implicit indication signal embedded in a set up, request or connection message to trigger a network element to modify network services to ensure appropriate call processing of a call.

The network services are handled and provided for in the IMS for the duration of the call after synchronisation. The IMS can handle the call even after one or more domain transfers. The network service may also suspend the network services for one of the subscribers (21 2b and/or 21 4b) in the CS domain.

The network services that are used by the subscribers (212b and 214b) are called invoked network services. These are network services the subscribers (212b and 214b) have set-up on their subscription with the network provider or on their user equipments (212a and/or 2l4a), which are invoked when they use their user equipments (212a and/or 214a) to communicate over the communications network 200. The invoked network services can include Call Barring Services, Supplementary Services, CallfHold and Transfer Services, ) Conference Call Services, Multiparty Call Services, Malicious Call Services and other useful network services and the like that subscribers (21 2b andlor 21 4b) or network providers need implemented on the communications network 200.

Referring again to Figure 8, an embodiment of the invention will be described in relation to the Call Barring network service. The Call Barring Service includes, but is not limited to, Operator Determined Barring (0DB), Barring of Outgoing International Calls (BOIC) and Barring of Outgoing International Calls except Home Public Land Mobile Network (BOIC-exH).

The first subscriber 212b originates a call using the first user equipment 212b to the second subscriber 21 4b on their second user equipment 21 4a. In the process of the first subscriber 212b originating the call to the second subscriber 21 4b, the first network element 202 may receive a setup message from the first subscriber's 212b user equipment 212a, and in response the second network element 204 notifies by a call origination message to the first network element 202 of the call origination.

The call origination is received by the first network element 202, which can be adapted to implement various functions such as call handling, which can include call setup, termination, anchoring and the like, this capability can include determination of whether a call from the first user equipment 21 2a should be handled or anchored in the IMS by the first or second network elements 202 or 204, and the like.

If the call is being handled in the second network element 204, then the second network element 204 transmits an indication signal over the communication interface 206 for synchronisation of Call Barring Services in relation to the call from the second network element 204 to the first network element 202. The Call Barring Services in relation to the call include the Call ) Barring Services from either or both subscribers 21 2b and 21 4b. The first network element 204, having received the indication signal proceeds to synchronise, between the CS domain and the IMS, the Call Barring Services in relation to the call. The IMS may now process the call based on the call barring services in relation to the call, depending on the outcome.

A connection will be set-up between the subscribers 21 2b and 21 4b depending on the Call Barring Service set-up that each subscriber has on their user equipments, i.e. if the second subscriber 214b has any form of Call Barring Service set-up then the first subscriber 21 2b may not be able to connect with the second subscriber 214b in accordance with the second subscriber's Call Barring Service set-up.

In some cases the Call Barring Services in relation to the call and the subscribers (21 2b and 21 4b) is suspend in the CS domain. This can prevent the CS domain from, among other things, accidentally invoking the Call Barring Service unnecessarily. Synchromsing the Call Barring Service set-up between the CS domain and IMS and handling the call in the IMS and processing the call in accordance with the network services, like Call Barring Services, in the IMS can prevent the CS domain improperly invoking the network services. In other cases, the Call Barring Service in relation to the call is suspended in the CS domain for the duration of the call.

Once the call terminates then the CS domain can regain control of the Call Barring Services that were suspended in relation to the call when the call was handled by the IMS. The communications network 200 includes many network elements, for example the first network element 202, or another additional network element, is made aware of the release of the call, and acts upon the release to control the resumption of Call Barring Services in the CS domain. )

In order to begin synchronisation of the network services, such as Call Barring Service, between the CS domain and the IMS, once the IMS decides to handle the call, a connection message, which includes an indication signal, is exchanged between the second network element 204 and the first network element 202 via the additional communication interface 206 for use by the first network element 202. The connection message, and in particular the indication signal, is used by the first network element 202 to initiate the synchronisation of the invoked network service, i.e. the Call Barring Service, in the JMS and possibly the suspension of the network service in the CS domain. Once the decision is made to handle the call in the IMS, the second network element 204 handles the call and exchanges the connection message In some preferred embodiments the indication signal includes an indication of handling the call. This allows the second network element 204 to initiate the synchronisation of the Call Barring Service between the CS domain and IMS and/or the suspension of this network service in the CS domain. The indication signal can also include a user equipment (21 2a andlor 21 4a) identification or a second user equipment (21 4a) identification such as a Calling Party identifier. In another embodiment the indication signal includes an indication of a type of destination address or a type of destination number.

In other embodiments, the second network element 204 instead uses an indication signal that includes a destination address to identify that synchronisation/suspension of Call Barring Services in relation to the should commence between the CS domain and IMS. In this case, after receiving the indication signal at the first network element 202, the first network element 202 determines if or whether the destination address of the indication signal is within a set of destination addresses known by the first network element 202 ) for use in determining if the call handling in the IMS will or is taking place.

Typically, the destination address can be, but is not limited to, an IP Multimedia Routing Number (IMRN). This is an example of an implicit indication signal of handling the call.

As there are many network elements that make up the communications network 200, let alone the CS domain and IMS, it may be advantageous to employ a third network element (not shown), where the second network element 204 exchanges the indication signal with the third network element, which then relays this to the first network element 202. The third network element updates the first network element 202 to suspend Call Barring Services in relation to the call in the CS domain. It can be envisaged that other network elements will need to receive the indication signal for notification of the call being handled in the IMS and to act accordingly or to notify other network elements accordingly.

The third network element includes storage for user information for supporting at least the first network element. The third network element further includes storage media for details of at least one authorised user equipment (21 2a and/or 21 4a) authorised to use the communications network 200. To ensure more functionality, the third network element may be a Home Subscriber Service and Home Location Register.

The second network elements 204 can include one or more functional elements adapted to perform, but not limited to, at least call handling, or at least a call setup procedure, a call termination procedure, and a call transfer between the CS domain and the IMS, and the like. One of the functional elements of the second network element 204 is adapted to perform the determination of call handling. In other embodiments, the second network element 204 further includes a Voice Call Continuity Application and/or all or other logic or functions of CAMEL. )

The first network element 202 can include storage media for details of at least one roaming user equipment, which could be either the first or second user equipment (212a andIor 214a) that has roamed into the area that the second network element 202 serves. In other cases, the first network element can be or have the functions of a mobile switching centre.

In overcoming some of the above-mentioned problems, the VCC Application (once the decision is taken to anchor a CS originated call in the IMS) synchronises with the CS domain so that Call Barring services in the CS domain is then (and only then disabled). The synchronisation can be an explicit indication or implicit indication (further details are given below).

Following this the Call Barring Services will then be handled and provided for in the IMS for the duration of that call until such time that there is a domain transfer, or the call ends (whichever occurs first) even after one of more domain transfers. In the meantime, Call Barring Services for that subscriber will in the CS domain be suspended.

Note: For sessions established in the ilvIS, or for domain transfer from the CS to the IMS, Outgoing Call Barring does not present the same problem. This is because a Telephony Application Server (TAS) providing the IMS session related services will be situated in the home network and invoked after the call has been anchored at the DTF.

Thus in the case of an IMS originated call it will act on the remote party ID and not on a re-routing number, which is the case for CS originated calls. Further, a request for domain transfer will terminate at the DTF and so not be subject to Call Barring Service checks in the IMS.

Referring to Figure 9, a logic flow of the synchronisation between the CS domain and IMS when a call is originated in the CS domain is illustrated. )

This overcomes the problems described in the previous sections in relation to synchronisation of invoked network services between the CS domain and IMS when a call originated in the CS domain.

This involves the VCC Application (which can include in part theCustomised Application for Mobile Enhanced Logic CAMEL) to, once the decision is taken to anchor a Circuit Switch (CS) domain originated call in the IP Multimedia Subsystem (IMS) domain, then indicate the decision to anchor and so synchronise Call Barring Services between the IMS and the CS domain, and suspend or disable Call Barring Services in the CS domain.

Otherwise, the checks and procedures on Call Barring Services in relation to the call are processed and then a decision is made to proceed with the call or not. After this, the call is processed accordingly.

As described in the following Figures (and has been described in the above embodiments of the invention) the initiation/determination of the synchronisation of Call Barring Services can be made through an explicit indication (or an indication signal or indication data field) or an implicit indication.

Following this synchronisation the Call Barring Services are then handled and provided for in the IMS for the duration of the call even after one of more domain transfers. In the meantime Call Barring Services for the subscribers placing and receiving the call will be suspended in the CS domain. The CS domain will regain control of CS Call Barring Services for that subscriber, or those subscribers, when the call terminates in the CS domain. The suspension in CS domain is only active for as long as the call is active in the CS domain.

In the preferred embodiments, described below, it is shown that resumption of Call Barring Services in the CS domain can be realised by the Visitor Mobile Service Centre/Visitor Location Register (VMSC/VLR) being aware of ) release for that call transaction. In particular, should there be a domain transfer taking the User Equipment or Subscribers from the CS domain to the IMS then that suspension of Call Barring services will no longer apply as the CS call leg gets released.

Referring to Figure 10, another embodiment of the invention is illustrated by a signal flow diagram between the network elements of the CS domain and the IMS is shown in which the VCC Application informs the Home Subscriber Service (HSS), through Sh interface, of a call being anchored in the IMS and the requirement for synchronisation and/or suspension of Call Barring Services.

Initially the call is set up (1. SETUP) in the CS domain via the VMSC/VLR, which transmits an Initial Detection Point (2. lnitialDP) to the VCC Application. In relation to the InitialDP, the VCC Application makes a decision to anchor the call in the IMS, which is triggered through the gsm Service Control Function (gsmSCF). The VCC Application initiates informing the HSS about anchoring the call. This is performed by the VCC Application transmitting an indication signal that the call is being anchored in the IMS, to the HSSIHome Location Register (HLR) via a communication interface for exchanging information, for example the Sh interface. The Sh interface is used to exchange information between SIP AS and HSS. The HSS/HLR is typically a central database that contains details of each user equipment or mobile phone subscriber that is authorized to use the GSM core network, including the CS domain and IMS. The HSS/HLR then updates the VMSC/VLR, by transmitting an indication signalling the call will be or has been anchored, and to thus proceed with synchronising Call Barring Services between the IMS and CS domains and suspending Call Barring Services in relation to the call in the CS domain. )

The VCC Application through gsmSCF anchors the call and gsmSCF is informed. Through gsmSCF the response of the InitialDP is then provided by transmitting a connection message to the VMSC/VLR, for example the CONNECT message of the current standard is used in this embodiment, however, this and all the embodiments of the present invention are not limited to using only the CONNECT message to send an indication signal. The connection message may include additional indication signals such as the IP Multimedia Routing Number or Original Called Party ID. The UE is informed by the VMSC that the call is proceeding and the VMSC, knowing the call is now anchored will leave the processing of Call Barring Services in relation to the call to the IMS. The call is allowed to proceed by VMSC by normal call processing.

The VCC Application awaits confirmation that Call Barring Services have been synchronised and suspended in the CS domain before instructing the gsmSCF to transmit the CONNECT message towards the VMSC. Protocol and signalling will be designed or enhanced to allow HSS/HLR to "inject" this information into the VMSC/VLR.

As the VMSC/VLR to regains control of CS Call Barring Services at the end of the CS transaction, this embodiment requires that HSS is updated when the call is no longer anchored. This in turn requires the HSS also updates the VMSC/VLR accordingly.

Referring to Figure 11, an additional preferred embodiment of the invention is illustrated in which the VMSC/VLR acts on an explicit indication in the CONNECT message transmitted by the VCC Application. The UE originates the call and it is set up by the \MSC/VLR, which sends an InitialDP to the VCC Application. In response to the InitialDP and after making the decision to anchor the call in the IMS, the VCC Application, along with or in hand with the gsmSCF, will include an indication signal within the CONNECT ) message itself, which is transmitted to the VMSC/VLR. The VMSC after receiving and interpreting the CONNECT message and the incorporated indication signal (which is an explicit indication of anchoring) acts upon the indication signal to suspend checking of, among other related services, remaining Operator Determined (OD) and Supplementary Services (SS) Call Barring for the call.

The provision of an indication signal within the CONNECT message that a call is anchored is used by the VMSCIVLR to act on for synchronising and suspending Call Barring Services related to the call. For further details, see also the illustration of the signalling flow of Figure 2 where it is identified when and who sends the CONNECT message.

As the implementation of interworking between gsmSCF and VCC Application is a matter of vendor choice, the embodiment here does not restrict which entity/network element provides this explicit indication but rather that the indication be in the CONNECT message that is transmitted back to the VMSC/VLR.

As with any enhancements to the IMS and CS domains, this embodiment of the invention would require changes to the way in which the VMSC processes the call.

Referring to Figure 12, a further preferred embodiment of an explicit indication signal that includes the type of called party number is illustrated.

After initial call setup and notification of call origination using InitialDP transmitted from the VMSC/VLR to the VCC Application, this embodiment provides for an indication signal that incorporates the type of destination address to be returned in the CONNECT message. This embodiment differs from that of when an explicit indication of VCC anchoring is provided in that the indication signal gives explicit indication not of what has been activated, ) but rather what the destination routing address (that which has been changed) in the CONNECT message signifies. The significance of the provided destination routing address is assessed at the VMSC/VLR, which can take the necessary action to suspendlsynchronise CS Call Barring Services in relation to the call.

If the indication signal is that the destination routing address as provided in the CONNECT message is an IP Multimedia Routing Number (IMRN), the VMSC/VLR can know that the call is VCC anchored since only by anchoring a call will the VCC Application return an IMRN. Based on this, the VMSC/VLR can act accordingly to suspend/synchronise CS Call Barring Services.

Furthermore, it can be envisaged that an indication signal incorporating an indication of the type of destination number could be used in future for direct or indirect indication of other network services, such as other invoked network services that use CAMEL signalling methods of the CS domain to enable inter-working with the IMS. Other examples of invoked network services are Call Barring Services, Supplementary Services, Call/Hold and Transfer Services, Conference Call Services, Multiparty Call Services, Malicious Call Services and other user and network services and the like. In addition, although CAMEL signalling is used as a specific example, other signalling applications, methods or processes that are adapted to perform a similar function or some of the functions of CAMEL signalling may be applied.

It is envisaged that to implement this embodiment appropriately, the call processing state machine of the VMSC/VLR will have to handle this type of changed Called Party Number. )

Referring to Figure 13, a further preferred embodiment of the invention provides an implicit indication and determination of a domain transfer request for the suspending checking of Call Barring Services by the VMSC/VLR network element. If the VMSC/VLR knows that the replaced or additional number in the SETUP message is an IMRN then the VMSC/VLR network element can conclude (without an explicit indication) that the call has been anchored in the IMS and that Call Barring Services have been checked accordingly, and hence suspension of the checking of Call Barring Services can be effected.

In this embodiment, what is meant by an implicit indication and determination is not that the VMSC/VLR network element is given an indication signal that the Called Party number given in the SE1'UP message is an IMRN. The difference here is that by virtue of checking that the Called Party number returned in the SETUP message is within a certain set, range or ranges of numbers that correspond to IMRNs then the VMSCNLR network element can determine that VCC anchoring has taken place and thus checking of Call Barring Services have to be suspended due to the domain transfer.

What is currently seen by the VMSC/VLR, is that the IMRN is just another (E 164) number. This embodiment requires modification of the VMSC/VLR to ensure it has knowledge of sets or ranges of E164 numbers being nothing but ilvIRNs. This information can be determinedlcreated using all inter co-operating CAMEL networks.

Referring to Figure 14, another embodiment of an aspect of the invention is illustrated that includes the user equipment (UE) providing an indication of call anchoring to the VMSCNLR. The UE can be made aware of a call being VCC anchored. This awareness is also on an individual call basis. Using an indication that the UE receives, the UE can return an indication signal to the VMSC/VLR network element that the current call has been anchored. The ) UE indicates to the CS Core Network that the ongoing call has been anchored.

The logic part that deals with CS Call Barring Services might be implemented different from the part performing the CAMEL signalling machine.

The UE provides an indication back to the CS core network that a call has been anchored. This indication can be provided in a new or changed container/Information Element (IE) or field within an IE in any of the Call Control protocol signalling messages.

Referring to Figure 15, a further embodiment of the invention is illustrated in which the VMSC/VLR processes the returned original Called Party Number.

Unlike previous embodiments, this embodiment does not involve suspension of the CS Call Barring Services. Instead, this embodiment requires that the VMSCIVLR continues to do its CS Call Barring Services. More specifically, the CS Call Barring Services now takes into account the original Called Party number that is returned in the CONNECT message in a separate container/Information Element.

Now referring to Figure 3, prior to Detection Point 2 (DP2), the service logic in the VMSCIVLR can utilize the Called Party Number as provided by the mobile, user equipment or subscriber, for its Call Barring Services checks.

After DP2, the service logic uses the original Called Party Number returned in the CONNECT message for its Call Barring Service checks.

If in the CS domain, the UE requests a domain transfer, the Called Number would be a VCC Domain Transfer Number (VDN). If User Equipment is international roaming, this VDN will already be judged to be an International Number. So if the subscriber has Barring of Outgoing International Calls (BOIC) set, then the VMSC network element could stop the call from proceeding. With respect to this issue, it is envisaged that the knowledge that the call in progress is being handled, or anchored in, for example the IMS, then the call barring services or other invoked network services that are to be processed within the CAMEL service logic (or other similar service logic, application or network element) may be deferred. This will prevent the VMSC network element prematurely stopping the call from proceeding, or duplicating any unnecessary checking of the invoked network services.

The invention is not limited to only the VMSC/VLR network element from receiving an indication, explicit or implicit, and using the indication to determine whether a call has been anchored or whether there is a domain transfer between domains, i.e. from the IMS to the CS domain and vice versa, and then if the call has been anchored in the IMS suspending Call Barring Services or synchronising Call Barring Services between the IMS and CS domains, and vice versa. In fact, the invention can apply to any other network element or element that has access, or can have access to the indication signals sent from the VCC Application or the user equipment or where the indication signals are sent from any other appropriate network element.

In addition, the invention is not limited to only the VCC Application handling IMS call anchoring and sending out an explicit or implicit indication signal of whether the call is being anchored or not, (although this is currently the case), in fact other IP Multimedia network elements, or even other network elements may be given the ability to determine call anchoring and send out an appropriate indication signal to a further network element or network element to synchronise or suspend Call Barring Services in relation to the call. The network element may be a user equipment that sends an indication of call anchoring to the responsible network element for suspending or synchronising Call Barring Services.

The invention is not limited to requiring synchronisation of network services between domains, it can include other operations such as selective disabling of CS or IMS network services at the VMSC, or subsequent handling of the network services that could be done in the IMS (in which case synchronisation can be appropriate) or elsewhere in the CS domain (e.g. in the gsmSCF).

Furthermore, the invention is not limited to only Call Barring Services, but other network services or invoked network services that may require an indication signal to enable the efficient inter-working of the CS domain with the IMS and vice versa during call origination and domain transfers. Other invoked network services can be used such as, but not limited to, Supplementary Services, Call/Hold and Transfer Services, Conference Call Services, Multiparty Call Services, Malicious Call Services and other user and network services and the like.

It will be apparent from the foregoing that many other embodiments or variants of the above are possible. The present invention extends to any and all such variants, and to any novel subject matter or combination thereof disclosed in the foregoing.

Claims

CLAIMS

I. A method of providing network services to one or more users in relation to a call in a communications network including a circuit switch (CS) domain, an IP multimedia subsystem (IMS), and a first network element, the method comprising modifying at least one of the network services in the IMS in response to a request message in relation to the call, received at the first network element, for switching the call from one of the network domains to the other.

2. The method of claim 1, wherein the request message comprises one or more indication signals that trigger the modifying of at least one of the network services in relation to the call.

3. The method of claim 2, wherein the first network element in response to receiving at least one of the indication signals, being an explicit indication signal or an implicit indication signal, triggers the modifying of at least one of the network services.

4. The method of claims 2 or 3, wherein at least one of the indication signals comprises an indication of transferring the call from one domain to the other.

5. The method of claim 4, wherein the call is transferred from the IMS to the CS domain.

6. The method of claims 4 or 5, wherein at least one of the indication signals differentiates between whether the request message is for a transfer of an originally terminated call to at least one of the users or for a transfer of an originated call from at least one of the users.

L

7. The method of any preceding claim, wherein the call originates in the IMS.

8. The method of any of claims 2 to 6, wherein the call originates in the CS domain and at least one of the indication signals comprises an indication of transferring the call from the CS domain to the IMS once a decision is taken to handle the CS domain originated call in the IMS.

9. The method of any preceding claim, wherein the modifying of at least one of the network services further comprises suspending at least one of the network services in relation to the call.

10. The method of any preceding claim, wherein the modifying of at least one of the network services further comprises synchronising at least one of the network services in relation to the call between the domains.

11. The method of claim 9, wherein the synchronising of at least one of the network services is between the IMS and the CS domain.

12. The method of any preceding claim, further comprising processing the call based on the network services, said at least one of the modified network services in relation to the call, and at the request message.

13. The method of any preceding claim, wherein the call is handled in the IMS.

14. The method of claim 13, wherein by handling the call in the IMS the call is anchored in the IMS.

15. The method of any preceding claim, wherein the request message, in relation to the call, is sent by one of the users.

16. The method of any preceding claim, wherein the request message is sent during the call between at least two of the users.

17. The method of any of claims 1 to 14, wherein the request message, in relation to the call, is sent from a second network element to the first network element.

18. The method of claim 17, wherein on origination of the call the second network element receives a notification of the call origination.

19. The method of claims 18, further comprising the second network element determining whether the call from the user should be handled in the IMS, wherein if the call is being handled in the IMS then the second network element transmits the request message to trigger modifying at least one of the network services in relation to the call.

20. The method of claim 19, further comprising receiving the indication signal at the first network element and modifying one or more of the network services by synchronising, between the CS domain and the IMS, at least one of the network services in relation to the call.

21. The method of any of claims 2 to 20, wherein at least one of the indication signals comprise an information element or field.

22. The method of claim 21, wherein the information element or field comprises a domain transfer number.

23. The method of any of claims 2 to 22, wherein the indication signal further comprises a user equipment identification. (4-

24. The method of claim 23, wherein the user equipment identification is a second user equipment identification.

25. The method of any of claims 2 to 24, wherein the indication signal further comprises a destination address.

26. The method of any claims 2 to 25, wherein the indication signal further comprises an indication of a type of destination address or a type of destination number.

27. The method of any preceding claim, wherein the network services comprise invoked network services.

28. The method of claim 27, wherein the invoked network services or network services comprise call barring services.

29. A user equipment apparatus for use in a communications network adapted to send the request message of any of claims Ito 28.

30. A network element adapted to receive the request message and modify the network services of any of claims 1 to 28.

31. A communications network adapted to perform the method of any of claims I to 28.

32. A method for synchronising network services substantially as hereinbefore described with reference to any of Figures 2, 4, 6, 7, 9 to 15 of the accompanying drawings.

33. A communications network substantially as hereinbefore described adapted to implement the methods of claim 32.

34. A user equipment apparatus substantially as hereinbefore described and adapted to implement the method substantially as hereinbefore described of Figure 7 with reference to the accompanying drawing.

35. A user equipment apparatus substantially as hereinbefore described and adapted to implement the method substantially as hereinbefore described of Figure 14 with reference to the accompanying drawing.