Rapid spectrum sensing in MIMO cognitive radio networks

Abstract

The radio frequency spectrum is a finite and progressively precious world resource and needs to be managed effectively. Due to the limitations of the natural frequency spectrum, it becomes obvious that the current static frequency allocation schemes cannot accommodate the requirements of an increasing number of higher data rate. As a result, innovative techniques that can offer new ways of exploiting the available spectrum are needed. Cognitive radio (CR) is a promising technology for overcoming the lack of available communication bands. It provides a solution by utilizing the spectrum holes that represent the potential opportunities for non-interfering use of spectrum which requires three main tasks- Spectrum Sensing, Spectrum Analysis and Spectrum Allocation. Spectrum sensing involves obtaining the spectrum usage characteristics across multiple dimensions such as time, space, frequency, and code and determining what type of signals are occupying the spectrum. In this research work a modified spectrum sensing method has been proposed based on Random Matrix Theory (RMT) using Discrete Cosine Transform (DCT) channel estimation of MIMO OFDM system. The proposed method overcomes the noise uncertainty problem and show very improved results even in very low SNR. The results have been compared with MMSE based channel estimation algorithm for spectrum sensing. The proposed methodology has low value of probability of false alarm and high value of probability of detection