Dynamic wordlength calibration for energy reduction FFT processors in wireless LAN

In this paper, we describe a way of reducing the energy for a fast Fourier Transform (FFT) processor using a dynamic wordlength technique in wireless OFDM systems. The proposed method is used to search an optimum wordlength of FFT processor by utilizing the Hamming distance to compare output binary data after channel decoding with maximum wordlength and other wordlengths. We used the proposed method with an automatic rate fallback (ARF) algorithm, which is used as a link adaptation. Using our approach reduces the energy used by up to 33.7% under a multipath fading channel environment.