Laboratory experiment of OFDM transmission using VLP and pre-FFT equalizer over ISI channels

A system using variable-length pilot symbols and a pre-FFT equalizer to overcome intersymbol interference (ISI) in OFDM transmission has been laboratory tested using a newly developed software-defined radio based test bed that is controlled using multiple CPUs. The results demonstrate that the system can provide a bit error rate of less than 10/sup -4/ for a fast multipath fading channel that has a moving velocity of more than 200 km/h with a delay spread of 1.9 /spl mu/s in the 5 GHz band. The proposed system is thus effective and feasible for fourth-generation mobile communication systems.