1. A receiving apparatus for canceling interference in a broadband wireless access (BWA) communication system, the receiving apparatus comprising: a wireless communication module for receiving signals from RX antennas; a preamble correlation measurer for measuring a preamble correlation coefficient from a preamble of the signal received by the wireless communication module; a data rearranger for determining a block size to divide the received signal from the preamble correlation coefficient, dividing the signal according to the determined block size, and rearranging the divided signals in a Space-Time coding (STC) mode; an estimate weight calculator for cross-correlating output signals of the data rearranger, rearranging the cross-correlated signals, auto-correlating the rearranged signals, and calculating an estimate weight to perform an interpolation operation; and an estimate signal decoding/combining unit for detecting desired signals from signals estimated by the estimate weight calculator and combining the detected signals.