In this paper, the orthogonal frequency division multiplexing (OFDM)- based Wi-Fi IEEE802.11a signal parameters (bandwidth, subcarrier spacing, and the number of subcarriers) are experimentally estimated over a band of signal to noise ratio (SNR) values. The estimation of the considered OFDM system parameters is blindly done with the aid of OFDM power spectrum properties. The estimation is evaluated under the assumption of additive white Gaussian noise (AWGN) and frequency selective multipath fading channels. The proposed estimation technique based on power spectrum processing technique which takes full advantage of the cryptic period of the OFDM signal. It was shown that the proposed method is applicable for medium SNR and it requires low computational complexity.