Performance analysis of signal cancellation method on QAM constellations in NC-OFDM

Non-contigious orthogonal frequency division multiplexing (NC-OFDM) is an emerging field in cognitive radio (CR) systems. Large sidelobe power and high peak power (PAPR) are major shortcomings of this system at the transmitter end. To jointly reduce both these parameters, the signal cancellation (SC) method is used here. Sidelobe suppression and PAPR reduction problem is a quadratically constrained quadratic program (QCQP) and solved using the CVX software. This method concentrates on joint optimization for reducing power of sidelobe and peak power by adding cancellation signal on primary user subcarrier and extending constellation points on secondary user subcarrier. This paper focuses on the performance analysis of signal cancellation method on different QAM constellations.