System and method for performing an inter mobile system handover using the internet telephony system

• US 6,424,638 B1
• Filed: 05/21/1999
• Issued: 07/23/2002
• Est. Priority Date: 05/21/1999
• Status: Expired due to Term

• Current Assignee: Ericsson, Inc. (Telefonaktiebolaget LM Ericsson)
• Original Assignee: Ericsson, Inc. (Telefonaktiebolaget LM Ericsson)
• Inventors: Ray, Dipankar, Alperovich, Vladimir
• Primary Examiner(s): Kincaid, Lester G.
• Assistant Examiner(s): Iqbal, Khawar
• Application Number:
  US09/316,310
• Time in Patent Office: 1,159 Days
• Field of Search: 455/426, 455/432, 455/434, 455/435, 455/438, 455/439, 455/560, 455/436, 455/440, 370/331, 370/334, 370/401, 370/465, 370/466
• US Class Current: 370/331
• CPC Class Codes: H04W 36/0066 of control information between different types of networks in order to establish a new radio link in the target network

Abstract

A telecommunications system and method is disclosed for utilizing an Internet telephony system to perform a handover of a call between different types of systems. When a serving mobile switching center (MSC) determines that there is not another MSC belonging to the same type of wireless system to which a handover can be performed, the serving MSC sends a message to an Internet Gatekeeper via an Internet Gateway for the serving MSC, inquiring whether there are any other types of wireless systems nearby. The Internet Gatekeeper maintains a database of all existing wireless systems within the area served by the Internet Gatekeeper. The Internet Gatekeeper chooses a target MSC of another wireless system (if possible), and transmits the identity of this target MSC back to the currently serving MSC. Thereafter, the currently serving MSC performs the handover to the target MSC by routing signaling messages through the Internet Gateway and the Internet Gatekeeper to the target MSC.

Claims

1. A telecommunications system for performing a handover of a call associated with a mobile station between different wireless systems, comprising:

first and second wireless systems, said first wireless system being in wireless communication with said mobile station for said call, said first wireless system determining that said handover of said call needs to be performed to said second wireless system; and

an Internet Gatekeeper within an Internet system for receiving an identity message from said first wireless system, determining an identity of said second wireless system for said handover and sending at least said identity of said second wireless system back to said first wireless system, said handover of said call being performed from said first wireless system to said second wireless system via said Internet system.

2. The telecommunications system of claim 1, further comprising:

at least one Internet Gateway in communication with said first and second wireless systems and said Internet Gatekeeper, said at least one Internet Gateway converting protocols of handover messages between said first and second wireless systems during said handover.

3. The telecommunications system of claim 2, wherein said at least one Internet Gateway further comprises:

a first Internet Gateway associated with said first wireless system for receiving first ones of said handover messages from said first wireless system, converting said first handover messages into Internet Protocol (IP) packets and routing said IP packets to said Internet Gatekeeper; and

a second Internet Gateway associated with said second wireless system for receiving said IP packets from said Internet Gatekeeper, converting said IP packets into second ones of said handover messages corresponding to said first handover messages but in a protocol of said second wireless system and transmitting said second handover messages to said second wireless system.

4. The telecommunications system of claim 1, further comprising:

a serving base station within said first wireless system in wireless communication with said mobile station, said identity message including location information for said serving base station.

5. The telecommunications system of claim 4, wherein said location information includes coordinates of said serving base station and a coverage radius for said serving base station.

6. The telecommunications system of claim 5, wherein said Internet Gatekeeper determines said identity of said second wireless system based upon said location information.

7. The telecommunications system of claim 6, further comprising:

a database within said Internet Gatekeeper for storing identity information for all wireless systems within an area served by said Internet Gatekeeper.

8. The telecommunications system of claim 7, wherein said identity information includes a list of identities of target base stations.

9. The telecommunications system of claim 8, wherein said identity of said second wireless system comprises said identity of a select one of said target base stations within said second wireless system, said select target base station having a coverage area at least adjacent to a coverage area for said serving base station.

10. The telecommunications system of claim 8, wherein said Internet Gatekeeper sends said identities of select ones of said target base stations to said first wireless system, said select target base stations having a coverage area at least adjacent to a coverage area for said serving base station, said first wireless system selecting a given one of said select target base stations to perform said handover to, said identity of said second wireless system comprising said identity of said given target base station.

11. The telecommunications system of claim 8, wherein said identity information includes a list of mobile switching centers within all wireless systems within said area served by said Internet Gatekeeper.

12. The telecommunications system of claim 11, wherein said Internet Gatekeeper multicasts said identity message to select ones of said mobile switching centers on said list that are within a different wireless system than said first wireless system.

13. The telecommunications system of claim 12, wherein said select mobile switching centers provide identities of target base stations served by said select mobile switching centers that have a coverage area at least adjacent to a coverage area of said serving base station to said Internet Gatekeeper.

14. The telecommunications system of claim 13, wherein said Internet Gatekeeper sends said identities of said target base stations to said first wireless system, said first wireless system selecting a select one of said target base stations to perform said handover to, said identity of said second wireless system comprising said identity of said select target base station.

15. The telecommunications system of claim 1, wherein said handover messages comprises signaling messages.

16. The telecommunications system of claim 1, wherein said handover messages include payloads.

17. The telecommunications system of claim 1, further comprising:

a first mobile switching center within said first wireless system for sending said first identity message.

18. The telecommunications system of claim 17, further comprising:

a second mobile switching center within said second wireless system, said handover messages being transmitted between said first and second mobile switching centers via said Internet Gatekeeper.

19. A method for performing a handover of a call associated with a mobile station between different wireless systems, comprising the steps of:

determining, by a first wireless systems in wireless communication with said mobile station for said call, that said handover needs to be performed;

receiving, by an Internet Gatekeeper within an Internet system, an identity message from said first wireless system to determine an identity of a second wireless system to perform said handover to;

sending at least said identity of said second wireless system from said Internet Gatekeeper back to said first wireless system; and

performing said handover of said call from said first wireless system to said second wireless system via said Internet system.

20. The method of claim 19, wherein said step of performing further comprises the step of:

converting protocols of handover messages between said first and second wireless systems during said handover of said call from said first wireless system to said second wireless system by at least one Internet Gateway in communication with said first and second wireless systems and said Internet Gatekeeper.

21. The method of claim 20, wherein said step of converting further comprises the steps of:

receiving, by a first Internet Gateway associated with said first wireless system, first ones of said handover messages from said first wireless system;

converting, by said first Internet Gateway, said first handover messages into Internet Protocol (IP) packets; and

transmitting said IP packets from said first Internet Gateway to said Internet Gatekeeper.

22. The method of claim 21, wherein said step of converting further comprises the steps of:

receiving, by a second Internet Gateway associated with said second wireless system, said IP packets from said Internet Gatekeeper;

converting, by said second Internet Gateway, said IP packets into second ones of said handover messages corresponding to said first handover messages but in a protocol of said second wireless system; and

transmitting said second handover messages from said second Internet Gateway to said second wireless system.

23. The method of claim 19, wherein said step of receiving further comprises the step of:

receiving said identity message including location information for a serving base station within said first wireless system serving said mobile station.

24. The method of claim 23, further comprising the step of:

determining, by said Internet Gatekeeper, said identity of said second wireless system based upon said location information.

25. The method of claim 24, wherein said step of determining further comprises the step of:

storing, within a database within said Internet Gatekeeper, identity information for all wireless systems within an area served by said Internet Gatekeeper.

26. The method of claim 25, wherein said step of storing further comprises the step of:

storing a list of identities of target base stations, said list comprising said identity information.

27. The method of claim 26, wherein said step of determining further comprises the step of:

determining said identity of said second wireless system as said identity of a select one of said target base stations within said second wireless system, said select target base station having a coverage area at least adjacent to a coverage area for said serving base station.

28. The method of claim 26, wherein said step of sending further comprises the steps of:

sending, by said Internet Gatekeeper, said identities of select ones of said target base stations to said first wireless system, said select target base stations having a coverage area at least adjacent to a coverage area for said serving base station; and

selecting, by said first wireless system, a given one of said select target base stations to perform said handover to, said identity of said second wireless system comprising said identity of said given target base station.

29. The method of claim 25, wherein said step of storing further comprises the step of:

storing, within said database, a list of mobile switching centers within all wireless systems within said area served by said Internet Gatekeeper, said list comprising said identity information.

30. The method of claim 29, wherein said step of determining further comprises the step of:

multicasting, by said Internet Gatekeeper, said identity message to select ones of said mobile switching centers on said list that are within a different wireless system than said first wireless system.

31. The method of claim 30, wherein said step of determining further comprises the step of:

providing, by said select mobile switching centers, identities of target base stations served by said select mobile switching centers that have a coverage area at least adjacent to a coverage area of said serving base station to said Internet Gatekeeper.

32. The method of claim 31, wherein said step of sending further comprises the steps of:

sending, by said Internet Gatekeeper, said identities of said target base stations to said first wireless system; and

selecting, by said first wireless system, a select one of said target base stations to perform said handover to, said identity of said second wireless system comprising said identity of said select target base station.

33. The method of claim 19, wherein said step of receiving further comprises the step of:

receiving said identity message from a first mobile switching center within said first wireless system.

34. The method of claim 33, wherein said step of performing further comprises the step of:

transmitting handover messages between said first mobile switching center and a second mobile switching center within said second wireless system via said Internet.