APPARATUS AND METHOD FOR CALCULATING SOFT DECISION VALUE INPUT TO CHANNEL DECODER IN A DATA COMMUNICATION SYSTEM

摘要

A 64-ary QAM (Quadrature Amplitude Modulation) demodulation apparatus and method for receiving an input signal Rk(Xk,Yk) comprised of a kth quadrature-phase signal Yk and a kth in-phase signal Xk, and generating soft decision values A(sk 5), A(sk 4), A(sk3), A(sk2), A(sk,1) and A(sko) for the input signal Rk(Xk, Yk are disclosed. A first soft decision value generator receives the quadrature-phase signal Yk of the received signal Rk and a distance value 2a between six demodulated symbols on the same axis. A second soft decision value generator receives the in-phase signal Xk of the received signal Rk and the distance value 2a between the six demodulated symbols on the same axis.