Four Time Windows Averaging Channel Estimation with Real and Imaginary TFI Pilot Signals for OFDM

Abstract

In orthogonal frequency division multiplexing (OFDM) systems, the pilot signal is inserted to obtain the channel state information (CSI). The time frequency interferometry (TFI) method reduces the number of pilot signals by using the real and null signals and obtains the accurate CSI by averaging the two time windows. On the other hand, many averaging operations are necessary to obtain more accurate CSI. Before now, we have proposed the pilot signal based on the imaginary and null signals. By using these characteristics, in this letter, we propose the real and imaginary TFI pilot signals to obtain the CSI from the four time windows averaging for OFDM systems.