In this work, spectrum sensing based on energy detection spectrum sensing in cognitive radio is discussed. This book describes the implementation of computational intelligence technique (i.e. genetic algorithm) for the efficient spectrum management/the efficient switching of secondary users according to primary users.The proposed technique is also works well when number of primary users and secondary users increased. The spectrum management time is very low using genetic algorithm. Efficient spectrum management and efficient switching of secondary users according to primary users are done using genetic algorithm.