A system and method for preventing a call from being dropped changes from a first
set of serving base station(s) for the call to a second set of serving base station(s)
which can be determined independently by both the wireless unit and the wireless
communications system. As such, the wireless unit can attempt to recover the call
using the second set of serving base station(s) even without the availability of
a communication link between the wireless unit and the current set of serving base
station(s). The wireless communications system can independently determine a second
set of serving base station(s) for the call using information known at both the
wireless communication system and at the wireless unit before the communication
link was severed. For example, the wireless unit and the communications system
can determine the second set of serving base station(s) using the candidate list
identified with a previous pilot strength measurement message (PSMM) known to have
been successfully reported to the wireless communications system. After the wireless
communications system and the wireless unit determine that a call is in danger
of being dropped, the wireless unit and the wireless communications system can
automatically add base station(s) in the candidate set to the active set in attempting
to recover the call.