According to recent reports, a flying radar (FR) onboard of UAV will provide high fidelity radar information on forward observation missions. However, such desired performance may be degraded when the FR shares the spectrum band with communication systems. In this letter, we study for the first time the coexistence between a FR and MIMO communication system. Specifically, we present an efficient framework to jointly deal with UAV's altitude optimization, clutter mitigation, and spectrum sharing with MIMO communication system. The proposed framework is based on using transmit precoding at both systems to maximize the SINR of the FR under rate constraints for the communication system, and power budget constraints for both systems. Meanwhile, it optimizes the FR altitude to provide an optimum trade-off between the excreted interference from the communication system encountered at low altitude and high detection probability of the target amongst clutters encountered at high altitude due to line-of-sight. Simulation results show the effectiveness of the proposed framework for scenarios where both clutter and interference exist.

Flying Radar; Spectrum sharing; UAV