Received power detection under multiple ON/OFF environment for registering radio environment database

To improve the spectrum utilization efficiency, a Radio Environment Database (RED) is considered to be used. The received power from primary user at each location is normally provided to the a cognitive radio system. In a conventional method, the transmit status of the primary user is assumed to be always ON for registering the sensed data to the database. In this paper, a temporary change of the primary user for radio environment database is considered, and a multiple ON/OFF detection method is mainly discussed. In this method, we focus on a distribution transition between the ON status and OFF status. To detect the transition point, use CUSUM (cumulative sum) algorithm and GLR (Generalized Likelihood Ratio) algorithm to detect the transition point. Finally, only ON power can be extracted by using the detected transition point and the sensing error reduction is possible.