Rayleigh fading compensation for 16QAM using FFT

Pilot symbol-assisted modulation (PSAM) has been proposed to overcome the Rayleigh fading. However, as the fading rate becomes more rapid, it is difficult to provide an exact interpolation with conventional PSAM. To compensate for the fast Rayleigh fading, a PSAM which calculates in the frequency domain rather than the time domain as in conventional PSAM is proposed. Although this PSAM scheme only needs the zero interpolation for fading estimation, it provides a very accurate estimate even in relatively fast Rayleigh fading environments. We introduce this PSAM using fast Fourier transform (FFT) and apply it to 16QAM and then show some results of computer simulations.