Practical Algorithms for Soft-Demapping of Dual-Carrier Modulated Symbols

We present practical algorithms for the soft demapping of dual-carrier modulated (DCM) symbols. DCM has been proposed in the recent multi-band orthogonal frequency division multiplexing (MB-OFDM) based ultra-wideband (UWB) systems for achieving high data rates (up to 480 Mb/s). The DCM constellation is essentially two closely coupled 16-QAM constellations. As such, we first look at a joint (or a 2D) demapping scheme, and then move on to look at a few ID demapping schemes whereby the two 16-QAM constellations are demapped individually. Our results show that a 2D demapping scheme which we term as the 2D-Max Log is the most attractive DCM demapping scheme from both implementation and performance viewpoints