Active Interference Cancellation for Multiple Narrow-band Primary Signals in Cognitive OFDM

摘要

In Cognitive OFDM, out-of-band (OOB) leakage of OFDM signal should be suppressed in order to avoid interference to primary signals. Active interference cancellation (AIC) is a novel OOB leakage suppressing technique. In this paper, AIC method for multiple narrow-band primary signals (NPSs) in cognitive OFDM is discussed. We propose a sub-optimal method of multiple NPSs AIC, which takes different NPSs' frequency locations and bandwidths into account. Besides, we provide a matrix elements pre-nullifying method to drop computational complexity of the sub-optimal method. Simulation results show that the NPSs' frequency locations have no significant impact on performance of multiple NPSs AIC method, while the performance is worse with increase of the NPSs' bandwidths. The low complexity multiple NPSs AIC method reduces complexity greatly, only with slight performance degradation.