Interference Mitigation Signal Shaping Techniques in Cognitive Radios

In the context of cognitive radio networks (CRNs), Orthogonal Frequency-Division Multiplexing (OFDM) offers an attractive solution for dynamic spectrum access (DSA) due to its ability to tailor the spectrum profile of the transmitted signal to suit the specific environment. However, a disadvantage of OFDM is the presence of side-lobes in the transmitted spectrum, which can lead to interference with neighbour users. This issue is particularly critical in CRNs where unlicensed users opportunistically utilize spectrum gaps (white spaces). This paper addresses this challenge by proposing novel signal shaping techniques to mitigate interference in CRNs. These techniques leverage a combined approach: a generalized sidelobe cancellation and the method of cancellation carriers. The efficacy of the proposed techniques is evaluated through computer simulations by analysing the power spectral density (PSD). The simulations are expected to demonstrate superior interference reduction compared to techniques reported in the contemporary literature.