Effects of channel estimation in adaptive loading gain of OFDM

The orthogonal frequency division multiplexing (OFDM) modulation scheme is adopted by more and more wireless communication systems to help achieve reliable and high-rate data transmission. Wideband wireless systems based on OFDM are limited in their performance by the dips in the frequency spectrum of the multipath fading channel. Channel estimation is not only useful for demodulation of the transmitted data but also for implementing the loading scheme for the transmitter, since the performance of an OFDM-based system can be augmented by the adaptive loading and power allocation of the subcarriers. We simulated two kinds of channel estimation schemes and an adaptive loading algorithm, and compared the effects of the channel estimation for loading gain. Simulation shows that the loading gain of the adaptive algorithm can be improved ulteriorly through better channel estimation.