Performance evaluation physical layer of IEEE 802.11 standards under fourier transform and wavelet transform over Rician fading channel

Orthogonal Frequency Division Multiplexing (OFDM) is multi carrier transmission technique used to achieve high data rates and are employed in various WLAN standards. Conventional OFDM uses an Inverse Fast Fourier Transform (IFFT) at the transmitter to modulate a high bit-rate signal onto a number of carriers and ensure orthogonality between the carriers. The main purpose of this paper is to replace FFT with wavelet transform in conventional OFDM multicarrier modulation. Wavelet transform based OFDM (WT-OFDM) is a multiplexing method in which data is assigned to wavelet sub bands having different time and frequency resolutions. We present a comparative study on FFT-OFDM and WT-OFDM in IEEE 802.11 system. The performance of FFT and WT OFDM for various modulation techniques such as BPSK, QPSK and DPSK was evaluated under Rician fading channels. We found that the WT-OFDM outperforms FFT-OFDM in Rician fading channels.