In the field of cognitive radio, Spectrum Efficiency Maximization in Cognitive Radio Systems makes excellent dynamic radio resource allocation algorithm design for the professional. Based on the low-power multiband Orthogonal Frequency Division Multiplexing (OFDM) Ultra Wideband (UWB) system, the book gives a comprehensive and in-depth analysis in the technologies of UWB and Cognitive Radio, formulates the spectrum efficiency maximization problem into a multidimensional multi-knapsack problem, and provides a solution to the optimization problem by creating three novel low-complexity algorithms for spectrum sensing and spectrum management. Simulations and mathematical analysis show that the new algorithms significantly increase the spectrum efficiency of the low-power UWB-based cognitive radio system with very low cost compared with the conventional radio resource allocation algorithms, such as water-filling and Hughes-Hartogs algorithm. The book provides a solid foundation for the future study in large-extent and high-density multiuser cognitive radio networks, which can fully explore the benefits of cognitive radio technology.