Frequency-Shift Offset-QAM for GFDM

This paper presents a novel perspective to apply the offset quadrature amplitude modulation (OQAM) scheme on top of the multicarrier waveform termed Generalized Frequency Division Multiplexing (GFDM). The conventional time-shift OQAM is described for GFDM and, with the introducing of the general use of unitary transform, an interesting counterpart, i.e., frequency-shift OQAM, is proposed. The conventional long prototype pulse with time-shift of one half subsymbol becomes a short prototype pulse with frequency-shift of one half subcarrier. The frequency-shift OQAM scheme offers advantages such as low out-of-band emission and low implementation complexity. The concept can be applied to the broader scope of filtered OFDM without penalties in terms of performance in time variant frequency-selective channels.