A novel transmit scheme for OFDM systems with virtual subcarriers

Based on the double repetition structure in the frequency domain and the proper pulse shaping filter in the time domain, a novel transmit scheme for orthogonal frequency division multiplexing (OFDM) systems with virtual subcarriers is proposed.Our proposed scheme with comb-type pilots can provide feasibility to reduce the channel estimation errors at the band edges with conventional inverse fast Fourier transform (IFFT)-based channel estimator.Also this transmit scheme can provide additional diversity compared to the conventional OFDM scheme.Meanwhile, the receiver schemes corresponding to the proposed transmit scheme are presented to obtain the advantages mentioned above.All these efficacies are confirmed by simulations.