Semi-blind channel estimation for OFDM systems via an EM-MAP algorithm

In the OFDM communication context, semi-blind algorithms allow to cope with Doppler effect due to the mobility of wireless systems. For slowly varying channels, the estimation process can be performed on a block of symbols assuming that the channel is constant over the block. This algorithm enhances the performance in terms of channel estimation with the additional advantage of a linear arithmetical complexity. In this paper, we propose an EM-MAP algorithm which takes into account a channel correlation model between the coefficients of the block structure. Simulations results presented in the context of 5 GHz WLANs show that this new algorithm performs better than the EM-block algorithm in the mobile environment.