Method and system for transferring a cellular telephone call between intelligent cell sites

• US 5,850,606 A
• Filed: 05/17/1996
• Issued: 12/15/1998
• Est. Priority Date: 05/17/1996
• Status: Expired due to Term

• Current Assignee: RPX Clearinghouse LLC (RPX Corporation)
• Original Assignee: BellSouth Corporation (AT&T, Inc.)
• Inventors: Bedingfield, James Carlton Sr., Gallagher, David A.
• Primary Examiner(s): Urban, Edward F.
• Application Number:
  US08/649,436
• Time in Patent Office: 942 Days
• Field of Search: 455/436, 455/439, 455/442, 455/461, 455/416, 455/432, 455/438, 455/445, 379/114, 379/202, 379/207
• US Class Current: 455/439
• CPC Class Codes: H04Q 11/0435 Details
• CPC Class Codes: H04Q 2213/13097 Numbering, addressing
• CPC Class Codes: H04Q 2213/13098 Mobile subscriber
• CPC Class Codes: H04Q 2213/13204 Protocols
• CPC Class Codes: H04Q 2213/13209 ISDN
• CPC Class Codes: H04Q 2213/1324 Conference call
• CPC Class Codes: H04Q 2213/1326 Consultation call, broker's call, call hold, toggling
• CPC Class Codes: H04Q 2213/1328 Call transfer, e.g. in PBX
• CPC Class Codes: H04Q 2213/13345 Intelligent networks, SCP
• CPC Class Codes: H04W 36/12 Reselecting a serving backbone network switching or routing node

Abstract

A method and system for performing a handoff of a cellular telephone call from a calling station to a mobile cellular telephone between an old intelligent cell site and a new intelligent cell site. The handoff is accomplished by using a conference bridge in a switch to connect a call segment to the new intelligent cell site to the call segments from the calling station to the old intelligent cell site. When a talk path to the new intelligent cell site is established, the talk path to the old intelligent cell site is terminated. The handoff is therefore accomplished by utilizing a conference bridge in the switch rather than putting an existing call on hold while a connection to a new intelligent cell site is established. Using a conference bridge to accomplish a handoff results in minimal interruption in the talk path of the call such that the handoff is imperceptible to the user.

Claims

1. In a cellular telecommunications network including a first switch connected to a first intelligent cell site, a second switch connected to a second intelligent cell site, and a third switch connected to a third intelligent cell site, said first switch and said third switch being connected to said second switch, wherein a call is established between a calling station and a mobile cellular telephone located within range of the first intelligent cell site, a method for transferring the call from the first intelligent cell site to the second intelligent cell site and then from the second intelligent cell site to the third intelligent cell site, comprising the steps of:

when the mobile cellular telephone moves within the range of the second intelligent cell site;

A. initiating a communication from the second intelligent cell site to the first intelligent cell site via the first switch;

B. reserving a conference bridge in the first switch responsive to receipt of the communication;

C. connecting on the conference bridge a first call segment from the calling station to the first switch, a second call segment from the first switch to the first intelligent cell site, and a third call segment from the first switch to the second intelligent cell site via a second switch, the first call segment being a segment of the call from the calling station to the first switch, the second call segment being another segment of the call from the first switch to the first intelligent cell site, and the third call segment being the communication from the second intelligent cell site via the second switch to the first switch;

D. transferring control of the call from the first intelligent cell site to the second intelligent cell site;

E. releasing the second call segment;

F. disconnecting the conference bridge; and

when the mobile cellular telephone moves within the range of the third intelligent cell site;

repeating steps A-F but with respect to the second intelligent cell site, the third intelligent cell site and the second switch so as to effect transfer to the control of the call from the second intelligent cell site to the third intelligent cell site in the same manner as the transferring of the call from the first intelligent cell site to the second intelligent cell site.

2. In a cellular telecommunications network including a first switch connected to a first intelligent cell site, a second switch connected to a second intelligent cell site, and a third switch connected to a third intelligent cell site, said first switch and said third switch being connected to said second switch, wherein a call is established between a calling station and a mobile cellular telephone located within range of the first intelligent cell site, a method for transferring the call from the first intelligent cell site to the second intelligent cell site and then from the second intelligent cell site to the third intelligent cell site, comprising the steps of:

when the mobile cellular telephone moves within the range of the second intelligent cell site;

A. initiating a communication from the second intelligent cell site to the second switch;

B. sending a message from the second switch to the first switch that includes a generic address parameter;

C. reserving a conference bridge in the first switch responsive to receipt of the message;

D. connecting on the conference bridge a first call segment from the calling station to the first switch, a second call segment from the first switch to the first intelligent cell site, and a third call segment from the first switch to the second intelligent cell site via a second switch, the first call segment being a segment of the call from the calling station to the first switch, the second call segment being another segment of the call from the first switch to the first intelligent cell site, and the third call segment being the communication from the second intelligent cell site via the second switch to the first switch;

E. transferring control of the call from the first intelligent cell site to the second intelligent cell site;

F. releasing the second call segment;

G. disconnecting the conference bridge; and

when the mobile cellular telephone moves within the range of the third intelligent cell site;

repeating steps A-G but with respect to the second intelligent cell site, the third intelligent cell site and the second switch so as to effect transfer of the control of the call from the second intelligent cell site to the third intelligent cell site in the same manner as the transferring of the call from the first intelligent cell site to the second intelligent cell site.

3. In a cellular telecommunications network including a first switch connected to a first intelligent cell site and a second switch connected to a second intelligent cell site, said first switch being connected to said second switch, wherein a call is established between a calling station and a mobile cellular telephone located within range of said first intelligent cell site, a method for transferring the call from said first intelligent cell site to said second intelligent cell site, comprising the steps of:

assigning a virtual number to said call;

when said mobile cellular telephone moves within range of said second intelligent cell site;

initiating a communication from said second intelligent cell site to said first switch using said virtual number;

reserving a conference bridge in said first switch responsive to receipt of said communication using said virtual number;

connecting on said conference bridge a first call segment from said calling station to said first switch, a second call segment from said first switch to said first intelligent cell site, and a third call segment from said first switch to said second intelligent cell site via said second switch;

transferring control of said call from said first intelligent cell site to said second intelligent cell site;

releasing said second call segment; and

disconnecting said conference bridge.