Institute of Electrical and Electronics Engineers
Active Interference Cancellation (AIC) is known to be a very effective technique for reducing the interference of OFDM side-lobes to primary licensed users in cognitive OFDM systems. However, AIC has some shortcomings such as high computational complexity and spectrum overshoot on the cancellation sub-carriers. Spectrum overshoot is mainly caused due to unconstrained or unbalanced power allocation to the cancellation tones used in AIC. In this paper, the authors propose an improved AIC technique in which the problem of spectrum overshoot is tackled. They show that by a modification to the solution of the optimization problem involved in AIC, they can obtain a trade-off between the amount of spectrum overshoot and side-lobe suppression without increasing the system complexity.