Stochastic Analysis of the Orthogonal Frequency Division Multiplexing Scheme

The Orthogonal Frequency Division Multiplexing (OFDM) scheme has been chosen as the transmission scheme for most digital television, digital radio and wireless standards. In this scheme the sub-carriers form a set of functions that are orthogonal to each other, that is, the integral of the product between any two of these functions within the interval of a symbol is null. The orthogonality ensures that the inter-symbolic interference in the frequencies of the sub-carriers is null. This paper presents an stochastic analysis of the OFDM signal, to obtain general expressions for its autocorrelation and power spectral density formulas. The resulting power spectral density is exactly what is produced by practical spectrum analyzers.