A performance analysis of OFDM systems in excessively dispersive multipath channels
For orthogonal frequency division multiplexing (OFDM), the discrete Fourier transform (DFT)-based processing at the receiver has been perceived equivalent to the matched filter (MF)-based processing. In this paper, we revisit the equivalence and mathematically show that when the guard interval is insufficient, the well-known DFT-based processing inherently causes more mtersymbol and interchannel interference (ISI/ICI) than the MF-based processing. Then, with the adverse increase of interference, analytical expressions for the link performance are derived in terms of bit error rate (BER). Numerical results from computer simulation and analysis are presented to justify our claims.
dispersive multipath channel orthogonal frequency division multiplexing (ofdm) discrete fourier transform (dft) interchannel interference (ici) intersymbol interference (isi)