Performance optimisation of multiple-input multiple-output radar for mainlobe interference suppression in a spectrum sharing environment

In a spectrum sharing environment, multiple-input multiple-output (MIMO) radar cannot effectively suppress mainlobe interference of the wireless communication system by adaptive beamforming. In this study, the initial phases optimisation of transmit waveforms is given to suppress the mainlobe interference for MIMO radar. Maximising the output signal-to-interference-plus-noise ratio (SINR) is employed as the optimisation criterion. Since the optimisation problem is a unimodular quadratic program which is NP-hard, three optimisation algorithms are presented to tackle it, based on the semi-definite relaxation, the phase-only variable metric and power method like iterations, respectively. Finally, the proposed methods are evaluated with computer simulations of beampttern and SINR performance.