Mobile station assisted soft handoff in a CDMA cellular communications system

In a cellular communication system in which a mobile user communicates through a mobile station transceiver with other users via at least one base station, wherein each base station in said system transmits a unique pilot signal and wherein each base station is in communication with a system controller, said mobile station transceiver comprising:

• a pilot signal strength measurement circuit for measuring signal strength of base station transmitted pilot signals from base stations included in a first list identifying a first set of said base stations;
• a comparator for comparing said measured pilot signal strengths to a first predetermined level;
• means for generating a second list identifying a second set of base stations by including within said second list those of said base stations on said first list for which said measured pilot signal strengths exceeded said first predetermined level;
• a mobile station transmitter for transmitting said second list to at least a first of said base stations with which said mobile station transceiver is currently in communication;
• a mobile station receiver for receiving, from at least one of said base stations with which said mobile unit transceiver is currently in communication, a third list identifying a third set of base stations available for communication with said mobile station transceiver, said third list being generated by said system controller in accordance with said second list of base stations and on the basis of base station availability information;
• and
• a mobile station controller for directing said mobile station transceiver to establish communication with said third set of base stations.

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, said cellular telephone system including a system controller for directing communications between system users of said cellular telephone system, a mobile station transceiver utilized by said mobile system user for communicating with said another system user via said at least one of said plurality of cell-sites, said mobile station transceiver comprising:

• a mobile station controller for determining, 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, a transition of said mobile system user from said one cell-site service area to a service area of another cell-site, said system controller being operative to generate a handoff request in response to said determination of said transition into said service area of said another cell-site;
• a mobile station transmitter for transmitting said handoff request to said one cell-site identifying said another cell-site;
• and
• means for concurrently communicating said user information signals between said mobile station transceiver and said one and another cell-sites, said concurrent communication being established by said system controller in accordance with said handoff request.