Virtual Array for Dual Function MIMO Radar Communication Systems using OTFS Waveforms

TL;DR

This paper introduces a novel virtual array construction method for MIMO dual-function radar communication systems using OTFS waveforms, enhancing sensing resolution with minimal data rate impact.

Contribution

It proposes a new approach to create a virtual array by using private TF bins, enabling high-resolution parameter estimation in MIMO radar systems.

Findings

Virtual array synthesis improves sensing resolution.

Few private bins suffice for significant sensing gains.

Minimal data rate reduction achieved with private bins.

Abstract

A MIMO dual-function radar communication (DFRC) system transmitting orthogonal time frequency space (OTFS) waveforms is considered. A key advantage of MIMO radar is its ability to create a virtual array, achieving higher sensing resolution than the physical receive array. In this paper, we propose a novel approach to construct a virtual array for the system under consideration. The transmit antennas can use the Doppler-delay (DD) domain bins in a shared fashion. A number of Time-Frequency (TF) bins, referred to as private bins, are exclusively assigned to specific transmit antennas. The TF signals received on the private bins are orthogonal and thus can be used to synthesize a virtual array, which, combined with coarse knowledge of radar parameters (i.e., angle, range, and velocity), enables high-resolution estimation of those parameters. The introduction of $N_p$ private bins necessitates a reduction in DD domain symbols, thereby reducing the data rate of each transmit antenna by $N_p-1$. However, even a small number of private bins is sufficient to achieve significant sensing gains with minimal communication rate loss.