Spectral Sculpting for OFDM based Cognitive Radio

In this article, the techniques of OFDM in cognitive radio have been studied. The objective of the study is to evaluate the effectiveness of various techniques to avoid interference. In cognitive radio while primary and secondary users are present at the same time, the key issue is to avoid interference to primary as well as secondary users. Cognitive radio involves software computing while detecting spectrum holes which constantly vary with time, and assign them to the secondary users. OFDM technique is widely used in implementing cognitive radio. OFDM systems are much simpler then FBMC techniques but they lack the ability to avoid crosstalk and inter carrier interference effectively. OFDM utilize guard bands to avoid such interferences, these guards bands however come at the cost of spectrum. Windowing techniques also are utilized in OFDM system. Length of window can determine the amount of interference occurring in the communication systems.