IB-DFE based equalizer for constant envelop OFDM systems

Abstract

Constant envelope OFDM (CE-OFDM) is a promising modulation technique for future millimeter wave (mmW) based wireless communications, since it allows low-cost and highly efficient power amplification based on strongly nonlinear amplifiers. The aim of this paper is to design a new iterative space-frequency equalizer, based on iterative block decision feedback equalization (IB-DFE) principle, for multiplexing MIMO CE-OFDM based systems. The equalizer is designed to take into account both inter-block and residual inter-carrier interferences by efficiently exploit the space-frequency diversity order inherent to these systems. The matrices for this 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.