A method for reducing the out-of-band emissions for OFDM systems

One of the drawbacks of orthogonal frequency division multiplexing (OFDM) systems is the large out-of-band (OOB) emissions. These emissions are undesirable and may cause harmful interference to adjacent channels (users). Reducing the OOB emissions may allow more users to access the spectrum especially in the case of dynamic spectrum access networks. In this paper, we investigate the ability of combining two practical OOB emissions reduction techniques. The combination is proposed to mitigate the drawbacks of each individual technique while providing significant OOB emissions reduction. The chosen techniques do not require performing complex optimizations which makes the combination suitable for practical implementations. The effectiveness of the proposed combination is verified via computer-based simulations as well as practical implementation. The implementation is done using Iris software defined radio along with the universal software radio peripheral (USRP-N210). Implementation results prove that this combination can be used in real-time applications.