Study on G-OFDM Noise Models

Abstract—G-OFDM is a variant of OFDM, which replaces the fast Fourier transform (IFFT) and fast Fourier transform (FFT) by the inverse very fast Fourier transform (IVFFT) and very fast Fourier transform (VFFT), at transmitter and receiver respectively. The VFFT is the lower complexity version of the FFT. This paper introduces noise models of the G-OFDM transmission system that we call the G distribution, used to represent the statistical description of the noise in G-OFDM. The task is carried out by simulation of the statistical behaviour of the G distribution. In our previous work, we have shown analytically that the non-uniform row-gain of the G matrix leads to non-uniform noise contributions to the signal-to-noise ratio (SNR) of each subcarrier in the G-OFDM system and degrades its performance. Here, with computer simulation, we show that non-uniform variation gives an almost uniform, flat shape of the G noise power spectrum, but with 40 % noise power greater than for OFDM. Keywords-component: Fourier matrix; G matrix; OFDM; white Gaussian noise; power spectral density, autocorrelation function