A simple frequency-domain equalizer over doubly-selective channel without feedback

Frequency-domain equalization (FDE) is prior than time-domain equalization in complexity. FDE is based on the cyclic signal property within a data block. This means that the channel must remain constant during this time interval. But in fast fading environments, the channel is time-variant. In order to deal with this problem, a variety of sub-block based FDE techniques have been proposed, but these kinds of algorithms have very high complexity because a tentative equalization and decoding are necessary before sub-block processed. In many practical applications requiring high real-time attribution, processing speed of algorithms is more important than processing capacity, so we must sacrifice performance of algorithm in exchange for speed at this time. In this paper, a simple FDE algorithm without tentative equalization and decoding is proposed for fast fading channel. The proposed method reduces the complexity of algorithm by preserving partial of the frequency equalization result instead of tentative equalizing and decoding. Numerical simulation results show that this lower complexity of algorithm can also effectively decrease the intersymbol interference(ISI) in fast fading environment.