In this paper we propose a method to overcome the SNR-wall for the detection of OFDM signal by exploiting the autocorrelation property of the cyclic prefix in multipath fading channel. Required SNR for signal detection at a given number of observation samples for a fixed false alarm probability and detection probability has been found out. Our result shows that there is about 6 dB advantage for the autocorrelation based detector over conventional energy detector for noise uncertainty parameter (U) equals to 3 with 〖10〗^4signal samples. Analytical results have been verified with simulation and close agreement has been found.
Auto-correlation based detection, cyclic prefix, noise uncertainty, SNR-wall