MIMO-based Multitaper detection over Nakagami channels for dynamic spectrum access devices

Abstract

The multitaper estimator is considered as the most powerful nonparametric method for reconstructing the power spectrum of a signal. The multitaper detector has been strongly recommended to be used for spectrum sensing in cognitive radio systems. In this paper we provide a new and accurate model for the Multitaper detector assuming that both the transmitting and detecting nodes are employing single-user multiple-input-multiple-output (MIMO) structures. We present closed form mathematical expressions for the performance of the decision variable within the hypotheses testing context. We model the decision variable using the Phase-Type distribution, where we derive the exact distribution parameters for both the null and the alternate hypotheses. Furthermore, we accurately bound the average probability of detection over Nakagami fading channels. Finally, the average probability of detection is maximized to yield a predetermined probability of false alarm. The results show that the obtained analytical models are accurate. As a generic trend, it is found that adjusting the length of observed sequences has no effect on the detector performance. On the other hand, it is found that increasing the number of receiving branches provides a significant enhancement for the MIMO-Multitaper method.