Establishing a Communication Session

A method of operating an IP Multimedia Subsystem Application Server to facilitate a communication session between a first user and a second user at a required Quality of Service, the method comprising:

• receiving a notification that a Policy and Charging Rules function associated with the first user has not authorised said required Quality of Service, the notification including an indication of additional Quality of Service required by the first user in order to achieve said required Quality of Service;
• requesting authorisation, from a Policy and Charging Rules function associated with the second user, for the additional Quality of Service for the first user;
• receiving a notification that the Policy and Charging Rules function associated with the second user has authorised said additional Quality of Service;
• and
• notifying the Policy and Charging Rules function associated with the first user that the additional Quality of Service has been authorised for the first user.

A method of operating a Policy and Charging Rules Function associated with a first user to establish a communication session between the first user and a second user at a required Quality of Service, the method comprising:

• receiving a Quality of Service authorisation request, the request including said required Quality of Service required by the first user and an additional Quality of Service required by the second user;
• determining if a subscription of the first user allows sufficient Quality of Service for both the required Quality of Service and the additional Quality of Service;
• and
• if the subscription of the first user does allow sufficient Quality of Service for both the required Quality of Service and the additional Quality of Service, responding to the Quality of Service authorisation request with an indication that the required Quality of Service and the additional Quality of Service have been authorised.

A method of operating a Policy and Charging Rules Function associated with a first user to control the establishment of a communication session between the first user and a second user at a required Quality of Service, the method comprising:

• receiving a Quality of Service authorisation request, the Quality of Service authorisation request including said required Quality of Service required by the first user;
• determining if a subscription of the first user allows sufficient Quality of Service for the required Quality of Service;
• and
• if the subscription of the first user does not allow sufficient Quality of Service for the required Quality of Service, determining an additional Quality of Service required by the first user in order to achieve said required Quality of Service, and responding to the Quality of Service authorisation request with an indication that the requested Quality of Service has not been authorised and including the additional Quality of Service required by the first user.

A method of operating an IP Multimedia Subsystem Proxy Call Session Control Function associated with a first user to facilitate a communication session between the first user and a second user at a required Quality of Service, the method comprising:

• receiving a request from an Application Server that the first user obtain authorisation, from a Policy and Charging Rules function associated with the first user, for additional Quality of Service for the second user in order that the second user can achieve the required Quality of Service;
• sending a Quality of Service authorisation request to the Policy and Charging Rules function associated with the first user, the Quality of Service authorisation request including said required Quality of Service and the additional Quality of Service;
• receiving a response to the Quality of Service authorisation request, the response including an indication that the required Quality of Service and the additional Quality of Service have been authorised;
• and
• notifying the Application Server that the Policy and Charging Rules function associated with the second user has authorised said additional Quality of Service.

A method of operating an IP Multimedia Subsystem Proxy Call Session Control Function associated with a first user to facilitate a communication session between the first user and a second user at a required Quality of Service, the method comprising:

• receiving a request from an Application Server to obtain authorisation, from a Policy and Charging Rules function associated with the first user, for the required Quality of Service, the request including an indication that additional Quality of Service has been authorised by a Policy and Charging Rules function associated with the second user;
• sending a Quality of Service authorisation request, to the Policy and Charging Rules function associated with the first user, the Quality of Service authorisation request including said required Quality of Service and an indication that the additional Quality of Service has been authorised;
• receiving a response to the Quality of Service authorisation request, the response including an indication that the required Quality of Service has been authorised for the first user;
• and
• notifying the Application Server that the Policy and Charging Rules function associated with the first user has authorised the required Quality of Service.

An apparatus configured to operate as an IP Multimedia Subsystem Application Server for facilitating a communication session between a first user and a second user at a required Quality of Service, the apparatus comprising:

• a receiver configured to receive a notification that a Policy and Charging Rules function associated with the first user has not authorised said required Quality of Service, the notification including an indication of additional Quality of Service required by the first user in order to achieve said required Quality of Service;
• a processing unit configured to generate a request for authorisation for the additional Quality of Service for the first user;
• a transmitter configured to send the authorisation request;
• the receiver further configured to receive a notification that the Policy and Charging Rules function associated with the second user has authorised said additional Quality of Service;
• and
• the transmitter further configured to notify the Policy and Charging Rules function associated with the first user that the additional Quality of Service has been authorised for the first user.

An apparatus configured to operate as a Policy and Charging Rules Function associated with a first user for establishing a communication session between the first user and a second user at a required Quality of Service, the apparatus comprising:

• a receiver configured to receive a Quality of Service authorisation request, the Quality of Service authorisation request including said required Quality of Service and an additional Quality of Service required by the second user;
• a processing unit configured to determine if a subscription of the first user allows sufficient Quality of Service for both the required Quality of Service and the additional Quality of Service;
• and
• a transmitter configured to respond to the Quality of Service authorisation request with an indication that the required Quality of Service and the additional Quality of Service have been authorised.

An apparatus to configured to operate as a Policy and Charging Rules Function associated with a first user for controlling the establishment of a communication session between the first user and a second user at a required Quality of Service, the apparatus comprising:

• a receiver configured to receive a Quality of Service authorisation request, the Quality of Service authorisation request including said required Quality of Service;
• a processing unit configured to determine if a subscription of the first user allows sufficient Quality of Service for the required Quality of Service, and, if the subscription of the first user does not allow sufficient Quality of Service for the required Quality of Service, to determine the additional Quality of Service required by the first user in order to achieve said required Quality of Service;
• and
• a transmitter configured to respond to the Quality of Service authorisation request with an indication that the required Quality of Service has not been authorised and including the additional Quality of Service.

An apparatus configured to operate as an IP Multimedia Subsystem Proxy Call Session Control Function associated with a first user for facilitating a communication session between the first user and a second user at a required Quality of Service, the apparatus comprising:

• a receiver configured to receive a request from an Application Server that the first user obtain authorisation, from a Policy and Charging Rules function associated with the first user, for additional Quality of Service for the second user in order that the second user can achieve the required Quality of Service;
• a processing unit configured to generate a Quality of Service authorisation request, the Quality of Service authorisation request including said required Quality of Service and the additional Quality of Service;
• a transmitter configured to send the Quality of Service authorisation request to the Policy and Charging Rules function associated with the first user;
• the receiver further configured to receive a response to the Quality of Service authorisation request, the response including an indication that the required Quality of Service and the additional Quality of Service have been authorised;
• and
• the transmitter further configured to notify the Application Server that the Policy and Charging Rules function associated with the second user has authorised said additional Quality of Service.

An apparatus configured to operate as an IP Multimedia Subsystem Proxy Call Session Control Function associated with a first user for facilitating a communication session between the first user and a second user at a required Quality of Service, the apparatus comprising:

• a receiver configured to receive a request from an Application Server to obtain authorisation, from a Policy and Charging Rules function associated with the first user, for the required Quality of Service, the request including an indication that additional Quality of Service has been authorised by a Policy and Charging Rules function associated with the second user;
• a processing unit configured to generate a Quality of Service authorisation request, the Quality of Service authorisation request including said required Quality of Service and an indication that the additional Quality of Service has been authorised;
• a transmitter configured to send the Quality of Service authorisation request to the Policy and Charging Rules function associated with the first user;
• the receiver further configured to receive a response to the Quality of Service authorisation request, the response including an indication that the required Quality of Service has been authorised for the first user;
• and
• the transmitter further configured to notify the Application Server that the Policy and Charging Rules function associated with the first user has authorised the required Quality of Service.