A Hybrid Framework for Spectrum Sharing in Cognitive Radio Systems With Dynamic Users

In this letter, we present a hybrid spectrum sharing approach in cognitive radio (CR) systems with dynamic users in which the secondary users (SU) may not accurately detect the presence of primary users (PU). As a consequence, there is an increased probability of collision between PU and SU transmissions, resulting in interference at the PU receiver. The proposed hybrid framework combines the interweave and underlay spectrum sharing paradigms, and limits interference to the PU through a mathematical expression that provides bounds on the SU power based on its sensing performance. The framework requires that the PU only share this expression and does not require that the PU reveal its waveform or other operating parameters to the SU. An example illustrating the proposed approach is also presented.