Virtual MIMO RADAR using OFDM-CDM Waveforms

Abstract

This paper addresses a new perspective on the exploitation ofdiversity resembling recent seminal proposals with multiple antennas known as MIMO radar. Our focus pursues similar advantages as spatial MIMO systems but intending to achieve the desired resistance over fading or/and SNR increase without relying on multiple antennas. We design an OFDM-CDM waveform well inspired in modern communications systems that creates a virtual MIMO system operating on the artificial 2D domain formed by a set ofwell separated carriers (OFDM) and several OFDM symbols each one modulated by orthogonal codes (CDM). We consider the most general scenario with moving targets and large size targets originating an equivalent time variant andfrequency selective channel model. Our proposal proceeds in two steps, a first one to reorthogonalize the transmitted set of OFDMsignal by proper time andfrequency synchronization (this stage provides range and velocity estimators), and a second one based on Neyman Pearson detection improved by the diversity gain.