Performance analysis of underlay waveform in the downlink of asynchronous OFDM/FBMC based Cognitive Radio transceivers

In this paper, we investigate the impact of the asynchronism on the performance of a Cognitive Radio (CR) network, using the underlay paradigm. We are also comparing this effect depending on which modulation technique we are using. We provide a new the theoretical aspect of interference analysis in the context of orthogonal frequency division multiplexing (OFDM) and the Filter Bank Multicarrier (FBMC) techniques in a CR network. In different communication systems, the asynchronism can be harmful on the system´s performance, and consequently can cause an asynchronous interference. Related works are evaluating the performance analytically either in terms of power allocation or spectrum sensing, and if the interference evaluation is done, it is not in the context of a CR network. In our work, we perform a theoretical analysis of the interference in terms of Bit Error Rate (BER) and Signal to Noise Ratio (SNR). Furthermore, we are also leading with a comparison between the two cases (OFDM or FBMC). Simulation results, compared to the theoretical approach confirm the validity of our analysis.