3D Spectrum hole detector using Support Vector Machine to enable D2D overlay on heterogeneous CR networks

This paper presents a novel architecture of a Cognitive Radio (CR) enabled heterogeneous network to obtain maximum spectrum efficiency by minimizing the interference to the Primary User (PU). In a wideband frequency co-operative spectrum sensing, different CR nodes can be assigned to different frequency bands to detect the spectrum hole. Spectrum hole is a 3-dimensional concept, where space, time and frequency are involved. By estimating the probable distance, time and frequency of primary user and applying transmit power control to the CR node, we can maximize the spectrum efficiency. Since in D2D (Device to Device) communication, the distance of communication is shorter and the propagation delays can be estimated, we can perform very accurate transmit power control. Using a 3-dimensional spectrum detector to detect spectrum holes in space, time and frequency will yield higher spectrum efficiency because it enhances the degrees of freedom from 1 to 3 and, hence, provides flexibility to use resources with lowest probability of interference.