Universal soft decision demodulator for M-ary adaptive modulation systems

In this paper, we present a very simple soft demapping algorithm for M-ary PSK and QAM schemes and their universal implementation for adaptive modulation systems. The proposed scheme estimates soft bit information contained in a symbol, with complexity that increases linearly, with modulation order, and achieves approximating performance to maximum likelihood detection. In addition, universal implementation of any M order modulation enables simple single hardware implementation of a demodulator in adaptive systems employing multiple modulation orders.