A Novel Overlap FFT Filter-Bank using Windowing and Smoothing Techniques to Reduce Adjacent Channel Interference for Flexible Spectrum Access

A flexible filter-bank is one of the key components to efficiently utilize non-contiguous unused spectrum on a secondary basis. As bandwidth of transmitted signals can vary according to vacant spectrum available for secondary use, it is necessary to reduce adjacent channel interference (ACI) as much as possible for efficient and flexible spectrum utilization. This paper proposes a novel overlap FFT filter-bank using windowing and smoothing techniques to reduce ACI and windowing and smoothing parameters are designed to minimize ACI. Computer simulation results show the proposed overlap FFT filter-bank can achieve 70dB smaller ACI compared with the conventional overlap FFT filter-bank when roll-off factor, alpha=0.