CSI-aided Demapping of Dual-Carrier Modulation for Multiband-OFDM

A novel CSI-aided demapping method for dual-carrier modulation (DCM) is proposed for multiband-OFDM systems. The proposed method utilizes the channel state information (CSI) to calculate the soft decision values, which are given by the approximate log-likelihood ratio (LLR). In this paper, it is shown that the soft decision values are given as the differences between two squared Euclidean distances. By reducing the noise-amplifying effect, the proposed method improves the error performance of conventional methods, by a signal-to-noise-ratio (SNR) of 3dB in the presence of channel estimation error and quantization noise. The VLSI architecture suitable for this method is also proposed, verifying that the performance gain comes with a slight increase of hardware complexity.