A PhD course by dr. Andrea Tani (DINFO)

The ever-increasing demand for bandwidth in the field of wireless communication systems because of multimedia and Internet of Things (IoT) applications results in a remarkable shortage in the available spectrum resources. Meanwhile, in the licensed spectrum, as reported by the U.S. Federal Communications Commission, it is the under-utilization of spectrum caused by regulated access “a more significant problem than the physical scarcity of spectrum”. The need of overcoming the static resource allocation has driven intense research interest on the topic of dynamic spectrum sharing among various systems with heterogeneous radio access technology, and different priorities to access licensed/unlicensed bands. These research efforts gave rise to the cognitive radio (CR) technology, which aims at exploiting the frequency, time, and space underutilized spectral resources by reusing then in an opportunistic manner. Noteworthy the dynamic spectrum sharing/management has been recognized as one potential 6G technological enablers in the category “new spectrum”.
The cognitive radio foundation is represented by the spectrum sensing, whose task is to
to decide whether a particular part of the spectrum is “available” or not. In other word we want to discriminate between two mutual exclusive hypotheses.

After a brief introduction on the application scenarios of the CR paradigm, the first part of the course provides the theoretical basis of the spectrum sensing in the framework of the detection theory, with a particular emphasis on the blind techniques.
The second part of the course is devoted to outline the problems encountered in the application of the blind spectrum sensing techniques when they meet in-band Full Duplex technology and when they operate at mmWave and Terahertz frequencies envisioned as potential 6G enablers.