A multi-carrier communication technique for interference-free spectrum sharing in cognitive radios

Future cognitive radio systems are envisioned to accommodate multiple users that are able to co-exist without causing harmful interference to each other. In this paper, we introduce a new modulation scheme, based on Single-Carrier FDMA (SC-FDMA) and Orthogonal FDMA (OFDMA), which enables interference-free spectrum sharing between radios that operate over different air interfaces. The basis of our approach is that non-OFDM signals can be sampled and the resulting data samples can be used as the dasiadata symbolspsila for an SC-FDMA style transmission.The concept is demonstrated by showing that a CPM-based radio and a conventional SC-FDMA radio can transmit over the same shared channel without interfering and thus without suffering any loss in performance.