APPARATUS AND METHOD OF BLIND MODULATION CLASSIFICATION OF BPSK/QPSK ROBUST TO SEVERE OFFSETS IN SATELLITE COMMUNICATION SYSTEM

摘要

An apparatus and a method of blind modulation classification of BPSK/QPSK robust to severe offsets in a satellite communication system are provided to achieve perfect BPSK/QPSK modulation classification only with a matching filtered reception signal without the help of an additional restorer. In an apparatus of blind modulation classification of BPSK/QPSK robust to severe offsets in a satellite communication system, first and second likelihood calculating devices(11,12) calculate each likelihood of reception baseband signals with respect to each modulation method(BPSK/QPSK). A maximum value setting device(13) searches a maximum value according to a likelihood value calculated through the first and second likelihood calculating devices(11,12) and sets a flag corresponding to the maximum value as 1 and the rest as o. First and second flag adding devices(14,15) add flags of each modulation method(BPSK/QPSK). A modulation flag setting device(16) selects the maximum value among the flags added through the first and second flag adding devices(14,15) and sets the modulation flag corresponding to the selected value. A modulation classification way determining device(17) adds the modulation flag outputted through the L times of repetitions of a modulation classification process and determines a larger modulation classification way between two as an actual modulation classification way.