I. Introduction
Over the past decades, multi-carrier modulation (MCM) has been well accepted as one of the main transmission technologies in wireless broadband communications [1]–[3]. As a classical MCM scheme, orthogonal frequency division multiplexing (OFDM) with cyclic prefix (CP) is of great popularity, thanks to its robustness against inter-symbol interference (ISI) and simple equalization structure. However, the use of CP to mitigate ISI in conventional OFDM-based transmissions comes at the expense of reduced spectral efficiency, especially in a severely time-dispersive fading channel.