Transition detection with spectrum database using weighted cooperative sensing

In order to improve spectrum utilization efficiency of Cognitive Radio (CR) systems, it is important for Secondary User (SU) to get knowledge about Primary User(PU)´s behavior when SU exploits opportunity to access spectrum. Radio Environment Database has recently been proposed to provide information about PU. Traditional advanced spectrum database constructed based on spectrum sensing method assumes that the transmit status of PU is always ON for updating the database information. However, it is not appropriate for recognizing in realistic environment because most of wireless systems does not always send the signal. In this paper, we propose a transition detection method using weighted cooperative sensing to construct a spectrum database for storing the power of PU obtained from sensor nodes. In the proposed method, the database gathers the information from sensor nodes and provides the previously stored information to generate the weight coefficient at the spectrum shared SUs. Then, we use a weighted cooperative sensing method to make a transition detection of PU behavior. Simulation results show that the proposed method can achieve a higher transition detection precision and the difference between the estimated transition point and the real transition point is smaller than the individual sensing.