Shaping Spectral Leakage: A Novel Low-Complexity Transceiver Architecture for Cognitive Radio

In this article, we propose a transceiver architecture based on orthogonal frequency-division multiplexing (OFDM) with transmit and receive windowing to reduce spectral leakage and reject adjacent channel interference (ACI). The transceiver enables the utilization of unused subbands in a fragmented spectrum with low complexity, which may be used in cognitive radio systems. We first show a multicarrier modulation (MCM) framework and the implementation of transmit and receive windowing. The intersymbol interference (ISI) resulting from receive windowing with a multipath channel is illustrated, and the performance of the presented transceiver architecture is evaluated and compared with several other MCM techniques. The results show that windowing offers a simple transceiver architecture with acceptable performance and is well suited for cognitive radio scenarios with noncontiguous spectrum fragments. Its performance can be further improved by using more advanced receivers.