Opportunistic Radar Waveform Design in Joint Radar and Cellular Communication Systems

The ever increasing demand for spectrum, due to services with data rate requirements and ongoing exponential increase in the number of wireless devices, has pushed for new methods that allow for a flexible and shared use of spectrum among different wireless and radar systems. Different systems need to sense the spectrum and adaptively design their transmitted waveforms in a manner such that they do not cause harmful interference to other systems. In this paper we consider a scenario where radar and wireless communication systems are operated jointly. The opportunistic radar constantly senses the spectrum and adapts its waveform based on the occupancy and maximum allowed power. A radar waveform is optimized for the target detection task such that it does not cause significant performance loss to the communication system. We show that the waveform optimized based on the Neyman-Pearson detector provides a very similar detection performance with the one optimized based on Mutual Information maximization. We also demonstrate that the detection performance improves if, at the radar receiver, the reflections off the target due to the communication signals are considered.