and finally the 501 patent:
patents.ibm.com
US5101501: Method and system for providing a soft handoff
in communications in a CDMA cellular telephone system
Inventor(s):
Gilhousen; Klein S., San Diego, CA
Padovani; Roberto, San Diego, CA
Wheatley, III; Charles E., Del Mar, CA
Applicant(s):
Qualcomm Incorporated, San Diego, CA
Publication Date:
March 31, 1992
Application Date:
Nov. 7, 1989
Application Number:
US1989000433030
IPC Class (Ed. 5):
H04Q 007/00; H04M 011/00;
US Class:
455/033; 455/034; 455/056; 379/060; 375/001;
Field of Search:
455-17,32-34,54,56,67 ; 379-59,60,63 ; 375-001 ;
Abstract: In a cellular telephone system a system for directing communications between a mobile
user and cell-sites as a mobile user changes cell-site service areas. The mobile user includes an
apparatus for, while in communication with another system user via one cell-site, determining a
transition of the mobile user from the cell-site service area to the service area of another cell-site.
The system includes circuitry responsive to the indication for coupling communications between the
mobile user and the other system user via the new cell-site while the mobile user also remains in
communication with the system user via the first cell-site. The system further includes apparatus
responsive to the coupling of the communications between the mobile user and the other system
user via the new cell-site for terminating the communications between the mobile user and another
system user via cell-site with communications continuing between the mobile user and the system
user via the new cell-site.
Exemplary Claim(s): Show all 23 claims
We claim:
1. In a cellular telephone system in which a mobile system user and another system user
communicate user information signals therebetween via at least one of a plurality of geographically
separated cell-sites each defining a respective geographic service area, a system for directing
communications between said mobile system user and said another system user via said at least one
of said plurality of cell-sites as said mobile system user changes cell-site service areas, comprising:
means for, while said mobile system user is in a service area of one cell-site and
communicating user information signals with said another system user via said one cell-site,
determining a transition of said mobile system user from said one cell-site service area to a
service area of another cell-site, and for providing a handoff request identifying said another
cell-site;
means responsive to said handoff request for coupling a communication of said user
information signals between said mobile system user and said another system user via said
another cell-site while said mobile system user and said another system user continue in
communication of said user information signals via said one cell-site such that said mobile
system user and said another system user concurrently communicate said user information
signals through said one cell-site and said another cell-site; and
means responsive to said coupling of communication of said user information signals between
said mobile system user and said another system user via said another cell-site for terminating
said communication of said user information signals between said mobile system user and said
another system user via said one cell-site with said communication of said user information
signals continuing between said mobile system user and said another system user via said
another cell-site. |
