Capacity Maximizing ICI Canceling Windows for OFDM in Time-Varying Channels

The rate-t/k (t ¿k) OFDM systems with the intercarrier interference (ICI) canceling windows are presented by generalizing the existing rate-1/k system and the capacity lower bounds of these systems fortime-varying frequency selective channels are analyzed. Based on the capacity analysis, the optimal windows maximizing the capacity lower bounds are designed numerically with an assumption that the channel is flat fading. The effects of ICI canceling windows on the capacity lower bounds are examined through numerical simulations and the results indicate that considerable performance improvement can be achieved by employing the proposed windows, as compared with the conventional systems with/ without windowing when the channel varies very rapidly.