Reducing Computational Complexity of Cancellation Carriers Algorithm by Using Unique Offline Optimized Pulses

Cancellation carriers’ method is a well-known technique in the OFDM overlay systems that employs a few optimized-weighted sinc-shape subcarriers at the edges ofsignal spectrum to mitigate the out-of-band power leakage and provide approximately free-interference transmission in thespectrum sharing scenarios. More employed cancellation tones can suppress more out-of-band power at the cost of further computational complexity and spectral inefficiency. In thispaper, a unique semi-orthogonal pulse which is designed offline is proposed that compared to using conventional cancellationcarriers can mitigate a certain out-of-band power through less complexity. The simulation results for a scenario with 64 OFDM carriers show that by employing three offline optimizedpulses, which occupy five OFDM subcarriers at each side of the signal spectrum, one can achieve a certain out-of-band powersuppression almost equal to condition when five conventional cancellation carriers are used at each side of the spectrum with the reward of 54% - 70% lower computational complexities

Keywords:

OFDM , cancellation carrier , Out-of-band suppression , Computational complexity , Cognitive radio