Patent Number:
7,042,954
Title:
Apparatus and method for calculating soft decision value input to channel decoder in a data communication system
Abstract:
A 64-ary QAM (Quadrature Amplitude Modulation) demodulation apparatus and method for receiving an input signal R.sub.k(X.sub.k,Y.sub.k) comprised of a k.sup.th quadrature-phase signal Y.sub.k and a k.sup.th in-phase signal X.sub.k, and generating soft decision values .LAMBDA.(s.sub.k,5), .LAMBDA.(s.sub.k,4), .LAMBDA.(s.sub.k,3), .LAMBDA.(s.sub.k,2), .LAMBDA.(s.sub.k,1) and .LAMBDA.(s.sub.k,0) for the input signal R.sub.k(X.sub.k, Y.sub.k) are disclosed. A first soft decision value generator receives the quadrature-phase signal Y.sub.k of the received signal R.sub.k and a distance value 2a between six demodulated symbols on the same axis, and generates soft decision values .LAMBDA.(s.sub.k,5), .LAMBDA.(s.sub.k,4) and .LAMBDA.(s.sub.k,3) for sixth, fifth, and fourth demodulated symbols. A second soft decision value generator receives the in-phase signal X.sub.k of the received signal R.sub.k and the distance value 2a between the six demodulated symbols on the same axis, and generates soft decision values .LAMBDA.(s.sub.k,2), .LAMBDA.(s.sub.k,1) and .LAMBDA.(s.sub.k,0) for third, second and first demodulated symbol.
Inventors:
Ha; Sang-Hyuck (Suwon-shi, KR), Kim; Min-Goo (Suwon-shi, KR)
Assignee:
Samsung Electronics Co., Ltd.
International Classification:
H04L 5/12 (20060101); H04L 23/02 (20060101)
Expiration Date:
5/09/02018