Cognitive Radar Waveform Design and Prototype for Coexistence With Communications

The need for cognitive radar systems that automatically adapt their transmit waveform and receive processing to the environment is growing along with the desire for integrating with communications. Indeed, the radio frequency spectrum will continue to become more crowded, and in this context, the new generation of radar systems will require to sense the frequency band and avoid making interference for other systems, like communications. In this paper, we present a spectrum-sharing prototype that demonstrates the application of waveform optimization for a scenario of coexistence between communications and cognitive radar systems. To this end, we define a bi-objective optimization problem for waveform design that provides both spectrum compatibility and small cross-correlation for the waveform set. The optimization problem is non-convex and NP-Hard, where we solve it iteratively using the Coordinate Descent (CD) framework. By sensing the environment in real-time and sequentially optimizing radar transmit waveform, the applicability of the proposed optimization algorithm is illustrated in a custom-built prototype, and its performance is validated and evaluated through SNR measurement for the radar system and throughput calculation for a realistic LTE downlink communication.