Noise analysis of DMT
Georg Tauböck · 2004
We consider discrete multitone (DMT, baseband OFDM) modulation and perform a detailed noise analysis which takes into account dependencies and power differences of the real and imaginary parts after the complex valued discrete Fourier transform (DFT). We show that for colored noise, rotated rectangular symbol constellations are more appropriate than the common (quadratic) QAM symbol constellations with respect to capacity and symbol error probability, and we derive formulas for the rotation angles and constellation sizes/densities.