Sub-Optimal Soft Decision For DCM Demodulator of MB-OFDM UWB System

In the multiband-orthogonal frequency division multiplexing (MB-OFDM) based on the ultra wide-band (UWB) system, a new modulation scheme called dual carrier modulation (DCM) has been introduced in terms of the high data rate transmission. Since the conventional channel state information (ClS)-aided demapping is not directly used in DCM, a new solution of CSI-aided demapping is required. In this paper, a sub-optimal soft decision scheme for demapping using log likelihood ratio (LLR) and the property of jointly Gaussian pdf is proposed. The simulation results show that the proposed method achieves 3 dB better packet error rate (PER) performance than zero forcing hard decision decoding and 8 dB better than soft decision decoding in one case of the high data rate 320 Mbps.