Blind equalization of OFDM signals on HF-channels

This paper deals with the analysis of OFDM signals in a NDA (non-data aided) context. Assuming the detection of an OFDM signal and the estimation of its bandwidth, our goal is first to estimate the number of sub-carriers. Then we apply the MUSIC algorithm with Akaike's decision criterion to obtain the number of sub-carriers: the number of carriers can be estimated with an error lower or equal to 9% in 100% of the cases until the SNR=10 dB. We can then demodulate the signal. The paper also discuss the improvement of the blind equalization of the demodulated signal to reduce as much as possible the bit error rate (BER). We show that the BER can be divided by 3 by using a transversal equalizer structure with a stochastic gradient algorithm.