Disclosed is an apparatus and method for searching a base station in a
mobile communications system, in which a mobile station acquires slot timing synchronization
from a first signal on a primary sync channel (P-SCH) out of the P-SCH and a secondary
sync channel (S-SCH) used for base station search, acquires frame timing synchronization
(Fsync) from a second signal on the S-SCH, and determines a primary scrambling
code group (PSCG) corresponding to the scrambling codes used by the respective
base stations. The method comprises calculating and accumulating P-SCH RSSI values
from the first signal at every slot and comparing the accumulated P-SCH RSSI values
with first and second accumulation thresholds and providing the first and second
search commands; and calculating S-SCH channel received signal strength indicator
(RSSI) values from the second signal at every slot in one frame, and updating S-SCH
RSSI values corresponding to the one frame as energy matrix values; calculating
energy hypotheses corresponding to the energy matrix values using the energy matrix
values and a predetermined secondary sync code (SSC) table in response to a first
search command, and determining energy hypotheses having a value higher than a
predetermined threshold as passed hypotheses; and calculating energy values for
the passed hypotheses using the determined passed hypotheses and the SSC table
in response to a second search command, and determining an energy hypothesis having
a maximum energy as the Fsync and the PSCG.
