A novel residual ISI cancellation for OFDM system with applications to Wireless LAN

A novel method is developed for the orthogonal frequency division multiplexing (OFDM) systems to eliminate the residual inter-symbol interference (ISI) introduced by the channel impulse response that exceeds the length of the guard interval. The method uses the decisions to estimate the residual ISI by FFT and IFFT with a very low computational complexity, and remove the residual ISI directly. Another advantage of this method is that it can be applied for non-sample spaced channel. Simulations for the application of the residual ISI cancellation algorithm to the Wireless LAN system based on IEEE Std 802.11a are performed. The simulation results show that the residual ISI cancellation algorithm presented in this paper provides good performance improvements on static fading ISI channels.