Performance Analysis of Unreliable Sensing for an Opportunistic Spectrum Sharing System

Opportunistic spectrum sharing (OSS) is a promising technique to improve spectrum utilization using cognitive radios. Unreliable spectrum sensing by cognitive radios is inevitable in the OSS system. In this paper, we analyze the types of unreliable sensing and their impact on the system performance. The secondary users equipped with cognitive radios sense channels that are unused by the primary users and utilize the idle channels. An ongoing secondary user also detects when a primary user accesses its channel and then either moves to another idle channel or moves to a buffer if no idle channel is available. Unreliable spectrum sensing is modeled by false alarm and misdetection events for both initiating and ongoing secondary users. We solve the steady-state probability vector of the system and derive a set of performance metrics of interest. Numerical results are presented to highlight the analysis. The proposed modeling method can be used to evaluate the performance of future opportunistic spectrum sharing networks.