Iterative space-frequency equalizer for CE-OFDM mmW based systems

In this paper we design a new iterative space-frequency equalizer, based on iterative block decision feedback equalization (IB-DFE) principle, for multiplexing MIMO CE-OFDM millimeter wave (mmW) based systems. Linear frequency domain equalizers are not the most efficient to separate the spatial streams due to inter-carrier interference. Therefore, we design a non-linear equalizer that takes into account both inter-block and residual inter-carrier interferences by efficiently exploit the high space-frequency diversity order inherent to these systems. The feedforward and feedback matrices for the proposed iterative space-frequency equalizer are obtained by minimizing the overall mean square error (MSE) of all data streams at each subcarrier. Our iterative scheme significantly outperforms the linear frequency domain equalizers, recently considered for CE-OFDM, with only a few iterations.