Performance Analysis of Opportunistic Spectrum Access System with Imperfect Spectrum Sensing

We study the performance of an opportunistic spectrum access (OSA) system with a general number of channels and imperfect spectrum sensing. The OSA system consists of a primary system serving primary users (PUs) and a secondary system serving secondary users (SUs). The PUs have strict priority over the SUs and the SUs opportunistically access the channels not occupied by the PUs temporarily. The system is modeled as a two-dimensional continuous-time Markov chain. We precisely specify the state-dependent transition rates due to imperfect sensing for the general channel number case by using simple recursive functions. Thus, efforts for exhaustively examining the explicit expressions for state transition rates are avoided. For performance metrics, we consider blocking probability, termination probability and success probability for each type of users. By the Markov model and carefully examining the spectrum sensing outcomes, the metrics may be easily derived. After obtaining the steady-state probability distribution, the required probabilities are numerically determined.