OFDM parameters estimation a time approach

We propose two approaches to determine the time parameters of an OFDM signal. We first determine the time symbol duration by exploiting the cyclostationnarity of the symbol. We apply the time-frequency transform and use the entropy criterion in order to estimate the "useful time" (time when information is sent) and the "guard time" (duration of the guard interval when "0" symbols are emitted). We can then compare the symbol duration and the "useful time" and "guard time" to verify the coherence of the result. Simulations have been made and we obtain good performance until SNR=3 dB.