Limited-Complexity Receiver Design for Passive/Active MIMO Radar Detection

In this paper, we develop efficient methods for devising lower complexity receivers that can achieve performance close to the full complexity receivers for passive/active multiple-input multiple-output (MIMO) radar. The method employed eliminates some parts of the test statistic to lower either hardware or software complexity. For the case of spatially uncorrelated reflection coefficients and spatially white clutter-plus-noise, the test statistic requires the computation of a set of matched filters, each matched to a signal from a different transmitter. In this case, our method is equivalent to selecting a specific set of transmitters to provide optimum performance. In the more general case of correlated clutter-plus-noise and reflection coefficients, then the test statistic requires the computation of a larger set of matched filters. These matched filters correlate the clutter-plus-noise free signal received at one receive antenna due to the signal transmitted from some transmit antenna and the signal received at another receive antenna. In the more general case, our algorithm picks the best of these matched filters to implement when the total number of these matched filters one can implement is limited.

I. Introduction

The performance of multiple-input-multiple-output (MIMO) radar systems has been widely investigated since 2004 [1]–[11]. MIMO radar can benefit from additional spatial separated antennas since it can observe a target from different directions [12]. Passive radar has also attracted attention over the past few years [13]–[15] due to the advantages of low cost, low probability of intercept, etc. In passive radar, existing illuminators of opportunity be employed to save the cost and energy on transmission.