Method and apparatuses for making use of virtual IMS subscriptions coupled with the identity of a non SIP compliant terminal for non-registered subscribers

1. A Service Interaction Manager in a packet based multimedia system, the Service Interaction Manager being connected to a Network Access Gateway of a network in communication with the packet based multimedia system, wherein a terminal connected in the network requests a service in the packet based multimedia system, but the terminal does not have a subscription in the packet based multimedia system, the Service Interaction Manager comprising:

a Table of Virtual Subscriptions for storing temporary virtual subscriptions;

a Coupling Function connected with the Network Access Gateway and the Table of Virtual Subscriptions, wherein the Coupling Function is configured to utilize the Table of Virtual Subscriptions to couple an available virtual subscription to a terminal identifier of the terminal and store in the Table of Virtual Subscriptions, a temporary association between the terminal identifier and the available virtual subscription; and

a Correlation Function connected with the requested service, the Table of Virtual Subscriptions, and a packet based multimedia system access gateway, wherein the Correlation Function is configured to:

receive a session start request message from the packet based multimedia system access gateway, the session start request message including the terminal identifier; and

utilize the Table of Virtual Subscriptions to correlate the session start request message with the available virtual subscription based on the terminal identifier received in the session start request message.

2. The Service Interaction Manager according to claim 1 , further comprising an Interface Handler configured to control use of a Network Interface Protocol towards the Network Access Gateway.

3. The Service Interaction Manager according to claim 1 , wherein the Table of Virtual Subscriptions stores groups of Virtual Subscriptions.

4. The Service Interaction Manager according to claim 1 , wherein the Table of Virtual Subscriptions includes a storage location for a terminal identifier for each Virtual Subscription.

5. The Service Interaction Manager according to claim 1 , wherein the Table of Virtual Subscriptions includes a storage location for a tag indicating whether each Virtual Subscription is available or coupled.

6. The Service Interaction Manager according to claim 1 , wherein the Table of Virtual Subscriptions includes a storage location for a time-stamp for each Virtual Subscription.

7. The Service Interaction Manager according to claim 1 , wherein the Table of Virtual Subscriptions includes a storage location for an account number for each Virtual Subscription.

8. The Service Interaction Manager according to claim 1 , wherein when the session is initiated, the correlation function is configured to:

decouple the terminal identifier from the virtual subscription; and

clear the temporary association between the terminal identifier and the virtual subscription, thereby setting the virtual subscription to available.

9. The Service Interaction Manager according to claim 6 , wherein when a maximum time a coupling may exist is exceeded, the correlation function is configured to:

decouple the terminal identifier from the virtual subscription; and

clear the temporary association between the terminal identifier and the virtual subscription, thereby setting the virtual subscription to available.