On Sidelobe Suppression for Multicarrier-Based Transmission in Dynamic Spectrum Access Networks

In this paper, we investigate the net sidelobe power reduction of noncontiguous orthogonal frequency-division-multiplexing (NC-OFDM) signals using an approach combining cancellation carriers (CCs) and modulated filter banks (MFBs). NC-OFDM can enable high-speed dynamic spectrum access (DSA) networks via transmission over several disjoint separate frequency bands. However, OFDM generally produces a substantial amount of out-of-band (OOB) interference that can potentially disrupt communications in adjacent wireless channels. One solution is to apply a filter bank, which is an array of bandpass filters that serves to isolate different frequency components of a signal. In this paper, we propose a combined OFDM sidelobe-suppression approach consisting of MFBs and the existing CC technique to achieve OOB radiation reduction. The simulation results show a significant net reduction of sidelobe power after using these two techniques. Furthermore, an algorithm has been developed to determine the number of OFDM data carriers (DCs) that can be transmitted in a given spectrum space.