Disclosed is a method for determining a paging alert mode of a mobile
terminal in a mobile communication system. The mobile terminal determines
whether there exists a sub-BTS, depending on a broadcasting channel
message provided in a cell formed by a main BTS. When the sub-BTS exists,
the mobile terminal monitors receipt of a beacon paging group frame from
the sub-BTS, and upon receipt of the beacon paging group frame, changes
the paging alert mode to a predetermined paging alert mode.