Main challenges in practical applications of cognitive radio

Facing more and more serious scarcity of radio resources in today´s society, cognitive radio offers a great solution from the theoretical level. But in the process of converting theoretical research into practical application, cognitive radio still has lots of inevitable problems. In this paper, demonstration about problems the cognitive radio encounters in practical applications is made from three aspects of spectrum sensing, spectrum handoff and information security. The analysis of the reasons why the problems occur and summary of present solutions are also introduced in the article.