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Table 3 A global comparison between FWT and FFT coarse sensing methods

From: Optimized spectrum sensing algorithms for cognitive LTE femtocells

FWT FFT
Better at obtaining a higher Pd which is important to satisfy the required primary user QoS. Used when the primary user QoS is of higher concern Better at obtaining a lower Pf which is important to achieve better spectral efficiency. Used when the spectral efficiency is of higher concern
The sensing resolution could be simply increased to reach RB resolution by applying further FWT decompositions To increase the sensing resolution we need to increase the FFT size
An ID algorithm could be applied at each wavelet decomposition stage to reduce the number of FWT operations with an acceptable performance The ID algorithm is not applicable to FFT where the operation is performed in one stage
In case the LTE receiver is an SDR and has a programmable FFT core, we lose the option of reusing this core which is used in the LTE OFDM receiver to perform spectrum sensing When the receiver is an SDR with a programmable FFT core, we can simply reuse the same FFT core used in the LTE OFDM receiver to perform spectrum sensing thus reducing complexity