Performance Analysis and Optimization of DCT-Based Multicarrier System on Frequency-Selective Fading Channels

Enhanced DCT-OFDM System With Index Modulation

“…This can be explained by the fact that the proposed EDCT-OFDM-IM exhibits larger sparsity than its DFT-OFDM-IM counterpart at the same SE. It should be noted that the simulated MEDs are slightly greater than that of theoretical MED because of the correlation gain as indicated in [12] [13].…”

“…Secondly, the excellent energy concentration and spectral compaction properties inherited by DCT render the DCT-OFDM system more robust against the inter carrier interference (ICI) effect [11]. Furthermore, since only half of the minimum subcarrier spacing is required to guarantee its subcarrier orthogonality [12], the total number of subcarriers in the DCT-OFDM system is doubled compared to the classic DFT-OFDM system. Due to these advantages, the DCT-OFDM constitutes a promising and highly spectrally multicarrier techniques for future wireless communication.…”

“…PROPOSED EDCT-OFDM-IM SYSTEM MODEL The major limitation of the DCT-OFDM is that, the circular convolution property which is always satisfied by DFT does not hold for DCT [9], [15]. To address this issue and to further improve the performance of DCT-OFDM-IM, we follow the implementation of an enhanced DCT-OFDM transceiver structure based on the pre-filtering method in [11], [12].…”

Index Modulation Assisted DCT-OFDM with Enhanced Transceiver Design

“…In this regard, the cyclicprefix (CP) based methods employed in general DFT-OFDM schemes to tackle the ICI and ISI issues do not apply any more. To address this issue, and further improve the DCT-OFDM-IM performance in [15], in this section, the optimum DCT-OFDM transceiver structure proposed in [18], [14], [16] is employed by cooperating with a time-reversed pre-filter and symmetric extended guard sequences to render the effective channel matrix diagonalizable by DCT in frequency domain, where one-tap equalization becomes applicable at the receiver side. In cooperation with this pre-filter, both prefix and suffix at no less than the channel memory are required as guard interval in the form of symmetric extension from modulated signal.…”

“…Particularly, for one-dimensional modulations (e.g., binary phase shift keying (BPSK)), the DCT-OFDM does not have the in-phase and quadrature-phase imbalance problem encountered in [12] in classic DFT-OFDM systems without the need of a quadrature modulator. In addition, unlike the traditional DFT-OFDM scheme, only half the minimum subcarrier spacing of typical DFT-OFDM is required for the DCT-OFDM needs [13], [14], [15]. Consequently, the number of subcarriers in the DCT-OFDM system occupying the same bandwidth is doubled.…”