A view on radar and communication systems coexistence and dual functionality in the era of spectrum sensing

In this paper, we discuss the state of radio frequency (RF) coexistence and how it benefits from dynamic spectrum sensing. We categorize coexistence of radar and communications in terms of their cooperation and non-cooperation in using the spectrum as well as their roles as primary, secondary, and dual users of the frequency bands. We describe the ways the radar can alter its parameters in response to the sensed spectrum through the completion of the cognitive perception-action cycle. The paper takes a broad view of the field and puts in context coordination of the two RF services through co-design, dual function, signal as well as system of opportunities. We present possible future research directions which will enable further innovations and progress in spectrum sharing and RF interference avoidance and mitigation.