Intelligent Reflecting Surface Enabled Sensing: Cramér-Rao Bound Optimization

by   Xianxin Song, et al.

This paper investigates intelligent reflecting surface (IRS) enabled non-line-of-sight (NLoS) wireless sensing, in which an IRS is dedicatedly deployed to assist an access point (AP) to sense a target at its NLoS region. It is assumed that the AP is equipped with multiple antennas and the IRS is equipped with a uniform linear array. We consider two types of target models, namely the point and extended targets, for which the AP aims to estimate the target's direction-of-arrival (DoA) and the target response matrix with respect to the IRS, respectively, based on the echo signals from the AP-IRS-target-IRS-AP link. Under this setup, we jointly design the transmit beamforming at the AP and the reflective beamforming at the IRS to minimize the Cramér-Rao bound (CRB) on the estimation error. Towards this end, we first obtain the CRB expressions for the two target models in closed form. It is shown that in the point target case, the CRB for estimating the DoA depends on both the transmit and reflective beamformers; while in the extended target case, the CRB for estimating the target response matrix only depends on the transmit beamformers. Next, for the point target case, we optimize the joint beamforming design to minimize the CRB, via alternating optimization, semi-definite relaxation, and successive convex approximation. For the extended target case, we obtain the optimal transmit beamforming solution to minimize the CRB in closed form. Finally, numerical results show that for both cases, the proposed designs based on CRB minimization achieve improved sensing performance in terms of mean squared error, as compared to other traditional schemes.


Intelligent Reflecting Surface Enabled Sensing: Cramér-Rao Lower Bound Optimization

This paper investigates intelligent reflecting surface (IRS) enabled non...

Cramér-Rao Bound Minimization for IRS-Enabled Multiuser Integrated Sensing and Communication with Extended Target

This paper investigates an intelligent reflecting surface (IRS) enabled ...

Multi-IRS-Enabled Integrated Sensing and Communications

This paper studies a multi-intelligent-reflecting-surface-(IRS)-enabled ...

Intelligent Reflecting Surface Assisted Secure Wireless Communications with Multiple-Transmit and Multiple-Receive Antennas

In this paper, we propose intelligent reflecting surfaces (IRS) assisted...

Fully-Passive versus Semi-Passive IRS-Enabled Sensing: SNR Analysis

This paper compares the signal-to-noise ratio (SNR) performance between ...

Secure Transmission Strategy for Intelligent Reflecting Surface Enhanced Wireless System

In this paper, we investigate the design of secure transmission framewor...

Intelligent Reflecting Surface Enhanced D2D Cooperative Computing

This paper investigates a device-to-device (D2D) cooperative computing s...

Please sign up or login with your details

Forgot password? Click here to reset