Patent ID: 7697639

Claim:
An apparatus for Binary Phase Shift Keying/Quadrature Phase Shift Keying (BPSK/QPSK) blind modulation classification in a satellite communication system, comprising: a first and a second likelihood value calculating means for calculating a likelihood value of a received baseband signal for each of BPSK and QPSK modulation modes, respectively; a maximum value setting means for obtaining a maximum value of the likelihood values or ith likelihood ratios calculated by the first and second likelihood value calculating means and setting a flag corresponding to the maximum value to have a first flag value and a flag corresponding to a remaining value to have a second flag value, wherein i is a positive integer; a first and a second flag combining means for combining the flags for the modulation modes, respectively; a modulation mode flag setting means for setting a corresponding modulation mode flag based upon the combining result; and a modulation mode deciding means for combining the modulation mode flags obtained by repeating a modulation classification processes in all of said means L times and deciding an actual modulation mode based upon combining the modulation mode flags result, wherein L is an integer greater than 1.