Increased Spectral Efficiency and Reliable Performance of Time Frequency Training Ofdm Using Mimo Technique

In this paper, the high spectral efficiency of a transmission scheme called Time frequency training (TFT) Orthogonal frequency division multiplexing (OFDM) using MIMO system is proposed. The time frequency joint channel estimation for TFT-OFDM utilizes the time-domain training sequence without interference cancellation to merely acquire the time delay profile of the channel, while the path coefficients are estimated by using the frequency-domain group pilots. The redundant group pilots only occupy about 1% of the useful subcarriers, thus TFT-OFDM still has much higher spectral efficiency than Cyclic prefix OFDM (CP-OFDM) by about 10% and by extending it using Multiple Input Multiple Output (MIMO) which produce much higher spectral efficiency than TFT-OFDM. Simulation results also demonstrate that TFT-OFDM using MIMO gives better performance than CP-OFDM and TFT-OFDM over time-varying channels.