OFDM with biorthogonal demultiplexing

In this paper we study biorthogonal schemes for frequency division multiplexing. These are schemes which use one given set of orthogonal waveforms for frequency division multiplexing at the transmitter, and a different set of waveforms, which is orthogonal to the multiplexing waveforms, for demultiplexing at the receiver. The well known cyclic prefix scheme is in this category. This biorthogonal demultiplexing allows for more design freedom, and we investigate its impact on designing robust OFDM transmultiplexers, and focus on waveforms which extend over several OFDM symbol intervals.