British Telecommunications Public Limited Company

Alan J Clapton

Christopher John Fenton

James Douglas Pettifor

Sunil Chotai

John A Lyle

A user is registered to use telecommunications services provided by a home service provider in a wired home network. When the user travels, the user may be provided with telecommunications services by another service provider operating in a wired visited fixed network. The user 'attaches' himself/herself to the visited fixed network which includes nominating a telephone to which calls made to a user's personal number may be forwarded. The user is also assigned a prefix number which enables him/her to make calls from any phone in the visited fixed network.

Mobility management

In a telephone network, a service control point is called by a switching center, if a flag has previously been set by some event (e.g. call charges crossing a threshold or the leaving of a voice mail message) when a call is being established or terminated. The switching center then operates in accordance with commands returned by the service control point. If no flags have been set, the service control point is not called and the call is treated by the switching center in a default manner.

Intelligent network services

A mobile telephone system provides a subscribe with services, for instance call barring and call forwarding, in dependence on the circumstances of the subscriber's mobile station. For instance, if the mobile station has a first network as its home network, the services provided are modified if it is detected that the mobile station has registered with a second network. In particular, international calls may be barred when on the home network, but permitted when on the second network so that the user may call his home country. This is carried out by having a number of different service profiles stored in the home network, for controlling the interactions between the mobile telephone and the current network, these service profiles being selected according to which network the mobile telephone is currently working to.

Location dependent service for mobile telephones

The arrangement disclosed allows a user of a mobile telephone,to use intelligent network (IN) services specific to his home network, regardless of whether the network,to which he is currently connected can support the service. When the user makes an outgoing call attempt (step 1) the associated signalling is transmitted over a signalling channel. The mobile switching centre (MSC),recognises a customer identity (encoded electronically in the call set-up signals ) and accesses the data relating to the user which is stored in a register,. The data in the register,relating to the user,includes a marking identifying him as an IN served customer, causing the MSC,to halt the call process and send a signal (,), protocol, to the service control point (SCP),in the user's home network. The SCP,then activates the user's service profile and as part of that profile recognises the need to retrieve additional information from the user,, e.g. a PIN (personal identity number) or some other information. Having identified the information needed, the SCP initiates a message,to the mobile station, for example requesting an authorisation code, which is passed back to the MS,by way of the switching centre MSC,and base station BSS,, using a signalling protocol. The user, having received the message,, responds such that the mobile station,sends a second signal,by way of the host network back to the SCP,. The SCP,acts on the message received and returns a response,to the MSC,, whereby the MSC,will then act on that information for example to set up a call, including a full speech channel if required (,). This system allows data to be transmitted directly between the SCP,and the user,, the host network not requiring to be compatible with the signalling protocols except for the initial and final states 1, 5. Moreover, since signalling channels are used, traffic (speech) channels, which have a larger bandwidth, are not used unless and until the call set-up process is completed.

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Capel St. Mary, United Kingdom

Alan J Clapton