METHOD FOR CALCULATING SOFT DECISION VALUE FOR MULTI-LEVEL DEMODULATION AND APPARATUS THEREOF

摘要

PURPOSE: A method for calculating a soft decision value for multi level demodulation and an apparatus thereof are provided, which obtain a required soft decision value by an input of a channel decoder without a mapping table or a complicated calculation to obtain a minimum distance value from a demodulator of a digital communication system to a receiving signal. CONSTITUTION: According to the apparatus for calculating a soft decision value used for a channel decoding in a demodulator of a digital communication system using 8-PSK(Phase Shift Keying) modulation method, a receiving signal analyzer(10) determines values of the first parameter and the second parameter by analyzing the receiving signal comprising an in-phase signal component and a quadrature phase signal component. And a soft decision value output unit(20) calculates the soft decision value by a mathematical equation using the receiving signal and the first parameter and the second parameter.