BFDM prototype for cognitive radio systems

In order to achieve better spectral efficiency, several prototypes have been suggested as physical layer candidates for cognitive radio systems as OFDM (Orthogonal Frequency Division Multiplexing), SRRC (Square Root Raised Cosine) and others. In such models, we are confronted to problems of interference between the cognitive users and licensed users which degrade the performances of using models. In order to reduce the level of interference, we propose in this paper a candidate for cognitive radio systems naming Biorthogonal Frequency Division Multiplexing (BFDM) with localized time-frequency waveforms. We compare the proposed prototype with another prototype functions used in different multicarrier systems, in terms of power spectral density. Simulations results are provided to illustrate the interference power and show that BFDM has an attractive benefit over other prototypes functions.