Comparative Study of CDMA and OFDM in WI-FI

There have been extensive research efforts on simulating Wireless Local Area Networks. Many papers have studied the performance of IEEE 802.11 WLANs by using simulation under different channels and for different modulations. In this paper we first simulate a simplified IEEE 802.11a standard based on Orthogonal Frequency Division Multiplexing (OFDM) with the cyclic prefix and IEEE 802.11b standard based on Direct-Sequence Code Division Multiple Accesses (DS-CDMA). Then a comparative study will be performed to evaluate them in Additive White Gaussian Noise (AWGN) channel with Rayleigh fading to resemble the real world scenario. We investigated their physical layer performances on the basis of Bit Error Rate (BER) and Signal-to-Noise Ratio (SNR). These parameters are discussed and compared in the two models. It has been demonstrated that OFDM system provides better performance in noisy conditions.