Capacity variance of OFDM systems over time and frequency selective fading channels

In this paper, the variance of OFDM system capacity has been thoroughly investigated. A mathematical expression of the capacity variance as a function of the number of subcarriers of an OFDM symbol, the number of multi-path fading channel, the system signal to noise ratio (SNR), the power profile of the fading channel, has been derived. Numerical and computer simulation results show that the capacity variance increases nearly linearly for the increase of SNR and the variance decreases for the increase of the multi-path number of the channel at a fixed cyclic prefix (CP) length.