Handover of wireless calls between systems supporting circuit and packet call models

• US 6,721,565 B1
• Filed: 08/07/2000
• Issued: 04/13/2004
• Est. Priority Date: 08/07/2000
• Status: Expired due to Term

• Current Assignee: WSOU Investments, LLC (WSOU Holdings, LLC)
• Original Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Inventors: Martin, Ronald Bruce, Lassers, Harold Aaron, Gafrick, John Matthew, Ejzak, Richard Paul
• Primary Examiner(s): Maung, Nay
• Assistant Examiner(s): TRINH, TAN H
• Application Number:
  US09/632,814
• Time in Patent Office: 1,345 Days
• Field of Search: 455/436, 455/438, 455/439, 455/440, 455/442, 455/444, 370/331, 370/332, 370/328, 370/338
• US Class Current: 455/436
• CPC Class Codes: H04W 36/0022 for transferring data sessions between adjacent core network technologies
• CPC Class Codes: H04W 36/00224 between packet switched [PS] and circuit switched [CS] network technologies, e.g. circuit switched fallback [CSFB]

Abstract

An improved wireless network provides intersystem handoffs between existing circuit wireless systems and packet systems. A packet wireless system is enhanced to provide translation between circuit and packet call models. A Media Gateway translates bearer traffic between formats used in each system. The Media Gateway, a Media Gateway Control Function, and an associated Call State Control Function, cooperate to emulate the behavior of a circuit wireless system, so that when interoperating with conventional circuit systems, the packet system appears to be another circuit wireless system. Where necessary, the Media Gateway, Media Gateway Control Function, and Call State Control Function further cooperate to emulate the functions of an anchor MSC of a circuit wireless system.

Claims

1. For use in conjunction with a wireless telecommunications network, said network having a portion adapted for packet wireless communications with a terminal and a portion adapted for circuit wireless communications with said terminal, a method for effecting a handover for a call which involves said terminal and another endpoint and which is using one of said portions, such that said call instead uses the other of said portions, comprising the steps of:

sending to said one of said portions a handover request with respect to said call;

emulating behavior of a handover-managing component of said one of said portions; and

providing a path for bearer traffic between said terminal and said endpoint through the other of said portions.

2. For use in conjunction with a wireless telecommunications network, said network having first and second portions each adapted for wireless communications with a terminal, said first portion being adapted to use a type of communications selected from the group of packet and circuit, said second portion being adapted to use a type of communications selected from the group of packet and circuit and different from the communications type of said first portion, a method of effecting a handover for a call which involves said terminal and another endpoint and which is using said first portion, such that said call thereafter uses said second portion, comprising the steps of:

a. sending to said second portion a handover request with respect to said call;

b. emulating behavior of a handover-managing component of one of said portions; and

c. providing a path for bearer traffic between said terminal and said endpoint through said second portion.

3. The method of claim 2 wherein step b thereof further comprises the step of:

b1. transmitting to said one of said portions messages according to a defined intersystem operations protocol.

4. The method of claim 2 wherein step b thereof further comprises the step of:

b1. Receiving from said one of said portions messages according to a defined intersystem operations protocol.

5. The method of claim 2 wherein step a thereof is performed by said first portion, and step b thereof is performed by said second portion to emulate a handover-managing component of said first portion.

6. The method of claim 2 wherein step a thereof is performed by said first portion, and step b thereof performed by said first portion to emulate a handover managing component of said second portion.

7. The method of claim 2 wherein step b thereof further comprises the step of:

b1. emulating the behavior of a mobile switching center in a circuit wireless system.

8. The method of claim 2 wherein step b thereof further comprises the step of:

b1. emulating the behavior of an anchor mobile switching center in a circuit wireless system.

9. The method of claim 2 wherein step c thereof further comprises the step of:

c1. translating bearer traffic between a form used by said first portion and a form used by said second portion.

10. The method of claim 2 further comprising the step of:

d. translating call state information between a call model used by said first portion and a call model used by said second portion.

11. The method of claim 2 further comprising the step of:

d. translating control messages between a form used by said first portion and a form used by said second portion.

12. The method of claim 2 wherein step c thereof further comprises the step of:

c1. translating bearer traffic between a format used by said second portion and a form used by a network associated with said endpoint.

13. The method of claim 2 wherein step c thereof further comprises the step of:

c1. translating call state information between a call model used by said second portion and a call model used by a network associated with said endpoint.

14. The method of claim 2 wherein step c thereof further comprises the step of:

c1. translating control messages between a form used by said second portion and a form used by a network associated with said endpoint.

15. The method of claim 2 wherein said first portion is adapted for packet communications and includes a gateway to translate bearer traffic between a form used by said first portion and a form used by said second portion, and further comprising the step of:

d. establishing a bearer path to said endpoint through said second portion and said gateway.

16. A telecommunications network for wireless service comprising:

a first wireless system adapted for communication with a terminal, said first system employing circuit technology;

a second wireless system adapted for communication with a terminal and said first system, said second system employing packet technology;

said second system including a media gateway adapted to translate bearer traffic between a form used in said first system and a form used in said second system, and a control device coupled to the media gateway and adapted to translate control traffic between a form used in said first system and a form used in said second system, and a handoff manager coupled to said control device and adapted to emulate the handoff management behavior of a circuit wireless system.