Compressed Sensing Time-Frequency Training OFDM With High Spectral Efficiency And Improved Performance Of The

Abstract--- Orthogonal frequency division multiplexing (OFDM) is widely recognized as the key technology for the next generation broadband wireless communication (BWC) systems. Besides high spectral efficiency, reliable performance over fast fading channels is becoming more and more important for OFDM-based BWC systems. The time domain synchronous OFDM (TDS-OFDM) has higher spectral efficiency than the standard cyclic prefix OFDM (CP-OFDM), but suffers from severe performance loss over high speed mobile channels since the required iterative interference cancellation between the training sequence (TS) and the OFDM data block, for the application of compressed sensing (CS) to the estimation of doubly selective channels within pulse-shaping multicarrier systems (which include orthogonal frequency- division multiplexing (OFDM) systems as a special case). By exploiting sparsity in the delay-Doppler domain, CS-based channel estimation allows for an increase in spectral efficiency through a reduction of the number of pilot symbols. In this paper, a fundamentally distinct OFDM-based transmission scheme called compressed sensing-time-frequency training OFDM (CS-TFT-OFDM) is proposed, whereby every CS-TFT-OFDM symbol has training information both in the time and frequency domains and also reduced the number of pilot symbols. Simulation results also demonstrate that CS-TFT-OFDM outperforms TFT-OFDM, CP-OFDM and TDS-OFDM in high speed mobile environments