Method and system for circuit-switched core network evolution, and network device

A network device, comprising:

• a network device obtained by upgrading a Mobile Switching Center Server (MSC-S) in a Circuit-Switched (CS) core network, and equivalent to a Telephony Application Server (TAS) in an IP Multimedia Subsystem (IMS) network;
• and
• an IMS interface unit, configured to exchange information with an other device in the IMS network;
• a CS interface unit, configured to exchange information with a device in a CS network;
• and
• a service processing unit, configured to:
• provide a voice service for a user in the IMS network after the IMS interface unit or the CS interface unit receives a service request from the user;
• perform service processing on the service request for an existing service;
• and send the service request for a new service to a corresponding application server in the IMS network for processing, wherein the service request for the existing service and the service request for the new service are initiated by a CS user who has subscribed to the new service;
• wherein
• the existing service comprises a service that can be processed by an original MSC-S, and the new service comprises a new service provided by the IMS network.

A system for Circuit Switched (CS) core network evolution, comprising:

• a Mobile Switching Center Server (MSC-S) Enhanced for IMS Centralized Services (ICS) (EMSC) wherein the EMSC is obtained by upgrading a Mobile Switching Center Server (MSC-S) in a CS core network and possesses functions of a Telephony Application Server (TAS) in the IMS network, and the system further comprises a Call Session Control Function (CSCF) of an IP Multimedia Subsystem (IMS) network;
• the CSCF in the IMS network is configured to send a received voice service request from a user in the IMS network to the EMSC;
• and
• the EMSC is configured to connect to the IMS network and serves as the TAS in the IMS network to provide a voice service for the user in the IMS network;
• the EMSC is further configured to:
• receive a service request sent by a CS user, perform service processing on the service request for an existing service, and send the service request for a new service to a corresponding application server in the IMS network for processing, wherein the service request for the existing service and the service request for the new service are initiated by the CS user who has subscribed to the new service;
• wherein
• the existing service comprises a service that can be processed by an original MSC-S, and the new service comprises a new service provided by the IMS network.

A method for providing a voice service in an IP Multimedia Subsystem (IMS) network, comprising:

• receiving, by a Telephony Application Server (TAS) in the IMS network, a voice service request from a user;
• when determining that the voice service is an existing service, performing service processing, and when determining that the voice service is a new service, sending the service request to a corresponding application server in the IMS network for processing, wherein the TAS is obtained by upgrading a Mobile Switching Center Server (MSC-S) in a Circuit-Switched (CS) core network and communicates through a communication interface between the TAS and a Call Session Control Function (CSCF) in the IMS network;
• wherein
• the existing service comprises a service that can be processed by an original MSC-S, and the new service comprises a new service provided by the IMS network.

A Telephony Application Server (TAS) in an IP Multimedia Subsystem (IMS) network, wherein:

• the TAS is obtained by upgrading a Mobile Switching Center Server (MSC-S) in a Circuit-Switched (CS) core network, and the TAS comprises:
• an IMS interface unit, configured to exchange information with an other device in the IMS network;
• and
• a service processing unit, configured to:
• receive a user's voice service request through the IMS interface unit;
• when determining that the service request is an existing service, perform processing on the service request, and when determining that the service request is a new service, send the service request to a corresponding application server in the IMS network for processing, wherein:
• the existing service comprises a service that can be processed by an original MSC-S, and the new service comprises a new service provided by the IMS network.

An IP Multimedia Subsystem (IMS) network system for providing a voice service, comprising a Telephony Application Server (TAS) and a Call Session Control Function (CSCF) in the IMS network, wherein:

• the TAS is obtained by upgrading a Mobile Switching Center Server (MSC-S) in a Circuit-Switched (CS) core network and is configured to:
• exchange information with the CSCF in the IMS network;
• after receiving a service request from a user, determining whether the service is an existing service or a new service;
• if the service is the existing service, perform processing on the service request;
• and if the service is the new service, send the service request to a corresponding application server in the IMS network for processing;
• the CSCF is configured to receive the service request from the user, and send a voice service request to the TAS for processing;
• wherein
• the existing service comprises a service that can be processed by an original MSC-S, and the new service comprises a new service provided by the IMS network.