IRS-Aided Radar: Enhanced Target Parameter Estimation via Intelligent Reflecting Surfaces

TL;DR

This paper explores how intelligent reflecting surfaces (IRS) can be integrated into radar systems to improve target parameter estimation, especially when the direct line-of-sight is weak or obstructed, by creating virtual links.

Contribution

It establishes the theoretical basis for IRS-assisted radar and demonstrates potential improvements in target estimation through virtual links in obstructed environments.

Findings

IRS can significantly enhance target estimation when LOS is weak.

Virtual links created by IRS improve radar performance in NLOS conditions.

Numerical results show IRS benefits when LOS is less than 10% of NLOS link strength.

Abstract

The intelligent reflecting surface (IRS) technology has recently attracted a lot of interest in wireless communications research. An IRS consists of passive reflective elements capable of tuning the phase, amplitude, frequency and polarization of the impinging waveforms. Given such desirable properties, the wireless channel characteristics can be controlled and optimized for specific signal design and processing needs -- thus promising significant potential in radar applications. In this paper, we establish the theoretical foundations for introducing IRS into a radar system and study the potential to improve target parameter estimation. More specifically, we will investigate the deployment of IRS in cases where the line-of-sight (LOS) link is weak or blocked by obstructions. We demonstrate that the IRS can provide a virtual or non-line-of-sight (NLOS) link between the radar and target leading to an enhanced radar performance. The effectiveness of such an IRS-provided virtual link in estimating the moving target parameters is illustrated under both optimized and non-optimized IRS scenarios. Numerical simulations indicate that the IRS can enhance the target parameter estimation when the LOS link is weaker than $\sim 10^{-1}$ in relative strength in comparison with the NLOS link.