A BROADBAND MIMO SENSING SYSTEM WITH COLOCATED NESTED ARRAYS: TRANSMIT SCHEME AND DIRECTION-OF-ARRIVAL ESTIMATION

In this paper, we aim to improve the degrees of freedom (DOF) and direction-of-arrival (DOA) estimation accuracy for a broadband MIMO sensing system with colocated nested arrays. A new transmit scheme, which decomposes the entire bandwidth used by the broadband MIMO system into multiple sub-bands, is proposed. Multiple pulses are employed to establish cyclic transmission between different transmit antennas so that signals from different antennas can be easily separated in the frequency domain at the receiver. A focus-based coherent DOA estimation method is also developed to make full use of the difference coarray aperture of the MIMO virtual array. Simulation results illustrate the superior performance of the proposed system.