Handover From Circuit Switched Domain to Circuit Switched Service Over Packet Switched Domain

1. A method in a radio network controller for initiating a handover of a mobile station, the method comprising: upon deciding, by the radio network controller, to perform the handover of a circuit switched service using a circuit switched bearer of the mobile station from a circuit switched domain to a packet switched domain in a mobile communications network, starting a circuit switched handover process by transmitting from the radio network controller to a mobile station controller a first relocation required message, wherein said first relocation required message comprises an Internet Protocol (IP) address and an access port allocated to the mobile station; and wherein the mobile communications network comprises a radio network and a core network, the core network comprises the mobile station controller, and the radio network comprises the radio network controller.

2. The method according to claim 1 , further comprising a step of the radio network controller requesting from the mobile station the IP address and the access port of the mobile station.

3. The method according to claim 1 , wherein the radio network includes a packet switching node, the method further comprising the step of the radio network controller upon deciding to perform the handover of the mobile station from the circuit switched domain to the packet switched domain starts a packet switched handover process by communicating to the packet switching node a second relocation required message, wherein said second relocation required message comprises the IP address and the access port allocated to the mobile station.

4. The method according to claim 3 , wherein the second relocation required message from the radio network controller is passed to the packet switching node via a presently used switching node.

5. The method according to claim 3 , wherein upon reception of the second relocation required request message the packet switching node reserves at least one of a local IP address and an access port and communicates the reserved at least one of the local IP address and the access port to the radio network controller.

6. The method according to claim 5 , wherein the radio network controller forwards the local IP address and the access port received to the mobile station.

7. The method according to claim 6 , wherein upon receipt of the local IP address and the access port allocated by the packet switching node, the mobile station uses this information in communication with the packet switching node.

8. The method according to claim 7 , wherein the packet switching node determines completion of the packet switched handover process from uplink packets sent by the mobile station.

9. The method according to claim 8 , wherein the packet switching node triggers an activation of the required packet switched bearer.

10. The method according to claim 7 wherein upon completion of the packet switched handover process, the mobile station sends a handover completed message to the packet switching node.

11. The method according to claim 1 , wherein: the handover is a handover to a CSoLTE solution; the circuit switched domain is a 2G/3G circuit switched domain; and, the packet switched domain is a Long Term Evolution/System Architecture Evolution (LTE/SAE) packet switched domain.

12. The method according to claim 1 , wherein the mobile station which initiated the circuit switched service in a 2G/3G radio access network of the circuit switched domain and then moved to a LTE coverage area of the packet switched domain is able to start using LTE/SAE broadband access upon completion of the handover.

13. A method in a base station controller for initiating a handover of a mobile station, the method comprising: upon deciding, by the base station controller, to perform the handover of a circuit switched service using a circuit switched bearer of the mobile station from a circuit switched domain to a packet switched domain in a mobile communications network, starting a circuit switched handover process by transmitting from the base station controller to a mobile station controller a handover required message, wherein said handover required message comprises an Internet Protocol (IP) address and an access port allocated to the mobile station; and wherein the mobile communications network comprises a radio network and a core network, the core network comprises the mobile station controller, and the radio network comprises the base station controller.

14. A radio network controller configured to assist in initiating a handover of a mobile station, the radio network controller comprising: a processor; and a memory that stores processor-executable instructions where the processor interfaces with the memory and executes the processor-executable instructions to perform operations as follows: upon deciding to perform the handover of a circuit switched service using a circuit switched bearer of the mobile station from a circuit switched domain to a packet switched domain in a mobile communications network, start a circuit switched handover process by transmitting to a mobile station controller a first relocation required message, wherein said first relocation required message comprising an Internet Protocol (IP) address and an access port allocated to the mobile station; and wherein the mobile communications network comprises a radio network and a core network, the core network comprises the mobile station controller, and the radio network comprises the radio network controller.

15. The radio network controller according to claim 14 , wherein the processor executes the processor-executable instructions to request from the mobile station its IP address and access port.

16. The radio network controller according to claim 14 , wherein: the handover is a handover to a CSoLTE solution; the circuit switched domain is a 2G/3G circuit switched domain; and, the packet switched domain is a Long Term Evolution/System Architecture Evolution (LTE/SAE) packet switched domain.

17. The radio network controller according to claim 14 , wherein the mobile station which initiated the circuit switched service in a 2G/3G radio access network of the circuit switched domain and then moved to a LTE coverage area of the packet switched domain is able to start using LTE/SAE broadband access upon completion of the handover.

18. A base station controller configured to assist in initiating a handover of a mobile station, the base station controller comprising: a processor; and a memory that stores processor-executable instructions where the processor interfaces with the memory and executes the processor-executable instructions to perform operations as follows: upon deciding to perform the handover of a circuit switched service using a circuit switched bearer of the mobile station from a circuit switched domain to a packet switched domain in a mobile communications network, start a circuit switched handover process by transmitting to a mobile station controller a handover required message, wherein said handover required message comprising an Internet Protocol (IP) address and an access port allocated to the mobile station; and wherein the mobile communications network comprises a radio network and a core network, the core network comprises the mobile station controller, and the radio network comprises the base station controller.

19. A Serving GPRS Support Node (SGSN) configured to assist in initiating a handover of a mobile station, the SGSN comprising: a processor; and a memory that stores processor-executable instructions where the processor interfaces with the memory and executes the processor-executable instructions to assist in initiating the handover of a circuit switched service using a circuit switched bearer of the mobile station from a circuit switched domain to a packet switched domain in a mobile communications network by performing an operation as follows: receiving, by the SGSN, from a radio network controller a relocation required message, wherein said relocation required message comprises an Internet Protocol (IP) address and an access port allocated to the mobile station; and wherein the mobile communications network comprising a radio network and a core network, the radio network comprising the radio network controller and the SGSN.

20. The SGSN according to claim 19 , wherein the processor executes the processor-executable instructions to reserve at least one of a local IP address and a User Datagram Protocol (UDP) port upon reception of the relocation required request message, and to communicate the reserved at least one of the local IP address and the UDP port to the radio network controller.

21. The SGSN according to claim 19 , wherein the processor executes the processor-executable instructions to determine completion of the handover from uplink packets sent by the mobile station.

22. The SGSN according to claim 19 , wherein the processor executes the processor-executable instructions to trigger an activation of the required packet switched bearer.

23. The radio network controller according to claim 14 , wherein the radio network includes a packet switching node, and wherein the processor executes the processor-executable instructions such that upon deciding to perform the handover of the mobile station from the circuit switched domain to the packet switched domain starts a packet switched handover process by communicating to the packet switching node a second relocation required message, wherein said second relocation required message comprises the IP address and the access port allocated to the mobile station.

24. The SGSN according to claim 19 , wherein: the handover is a handover to a CSoLTE solution; the circuit switched domain is a 2G/3G circuit switched domain; and, the packet switched domain is a Long Term Evolution/System Architecture Evolution (LTE/SAE) packet switched domain.

25. The SGSN according to claim 19 , wherein the mobile station which initiated the circuit switched service in a 2G/3G radio access network of the circuit switched domain and then moved to a LTE coverage area of the packet switched domain is able to start using LTE/SAE broadband access upon completion of the handover.

26. A Serving GPRS Support Node (SGSN) configured to assist in initiating a handover of a mobile station, the SGSN comprising: a processor; and a memory that stores processor-executable instructions where the processor interfaces with the memory and executes the processor-executable instructions to assist in initiating the handover of a circuit switched service using a circuit switched bearer of the mobile station from a circuit switched domain to a packet switched domain in a mobile communications network by performing an operation as follows: receiving, by the SGSN, from a base station controller a handover required message, wherein said handover required message comprises an Internet Protocol (IP) address and an access port allocated to the mobile station; and wherein the mobile communications network comprising a radio network and a core network, the radio network comprising the base station controller and the SGSN.