On non-contiguous multicarrier waveforms for spectrally opportunistic cognitive radio systems

Multicarrier modulation is well suited for future wireless communication systems due to its ability to opportunistically transmit across unoccupied frequency bands. In addition to multicarrier modulation being able to attain high data rates with a sufficient level of error robustness, it also has the potential to achieve transmission flexibility via the non-contiguous access of wireless spectrum. In this paper, we shall investigate two approaches for enabling non-contiguous multicarrier modulation that can be used to facilitate spectrally opportunistic cognitive radio systems. One of the approaches is a variant of orthogonal frequency division multiplexing (OFDM), called non-contiguous OFDM (NC-OFDM), while the other approach is based the noncontiguous version of the filter bank approach non-orthogonal frequency division multiplexing (NOFDM), referred to as noncontiguous NOFDM (NC-NOFDM). The performance of these two approaches is assessed in terms of interference mitigation, which involves the use of actual spectrum measurement data, as well as computational complexity.