This paper investigates intelligent reflecting surface (IRS) enabled non-line-of-sight (NLoS) wireless sensing, in which an IRS is dedicatedly deployed to assist access point (AP) sense a target at its NLoS region. It assumed that the AP equipped with multiple antennas and uniform linear array. We consider two types of models, namely extended targets, for aims estimate target's direction-of-arr...

In this letter, we consider signals with a low-rank covariance matrix which reside in a low-dimensional subspace and can be written in terms of a finite (small) number of parameters. Although such signals do not necessarily have a sparse representation in a finite basis, they possess a sparse structure which makes it possible to recover the signal from compressed measurements. We study the stat...

The use of the reflected Global Navigation Satellite Systems' (GNSS) signals in Earth observation applications, referred to as GNSS reflectometry (GNSS-R), has been already studied for more than two decades. However, the estimation precision that can be achieved by GNSS-R sensors in some particular scenarios is still not fully understood yet. In an effort to partially fill this gap, in this pap...

This paper address the joint direction-of-arrival (DOA) and time delay (TD) estimation problem, which is a key technique for accurate indoor localization in next generation WiFi and 5G networks. We propose an efficient approximate maximum likelihood (AML) algorithm for this problem, which updates the DOA and TD parameters alternatingly. Then, we present closed-form Cramer-Rao bound (CRB) for jo...

It is well known that iterative channel estimation and OFDM signals detection can significantly improve the performance of communication system. However, its performance is poor due to the modelling error of basis expansion model (BEM) being large enough and can not being ignored in rapidly time-variant channels. In this paper, channel estimation and OFDM signals detection are integrated into a...

We consider the role of array geometry on the Direction of Arrival (DOA) estimating performance of the array where the impinging signal is wideband. We concentrate on arrays that have isotropic performance. An isotropic array is one whose Cramér Rao bound (CRB) on the DOA of a single source is uniform for all angles. We derive the necessary and sufficient conditions on the location of array ele...

A new approach to the problem of joint azimuth-elevation-carrier (AEC) estimation of narrowband signals is introduced. The proposed approach makes it possible to solve the problem by using only spatial samples taken by volume antenna arrays. The sufficient conditions in terms of array geometry are formulated and proved. The simulation shows that the iterative Newton-based maximum likelihood (ML...

We present the gradient and Hessian of the trace of the multivariate Cramér-Rao bound (CRB) formula for unknown impinging angles of plane waves with non-unitary beamspace measurements,. These gradient and Hessian can be used to find the optimal beamspace transformation matrix, i.e., the optimum beamsteering angles, using the Newton-Raphson iteration. These trace formulas are particularly useful...

The Cramer-Rao Bound (CRB) analysis shows that ultra-wideband (UWB) technique can provide precise timing and positioning, thanks to its huge bandwidth. In this paper, we apply the UWB signal for the energy detection based time-of-arrival (ToA) estimation. We analyze the mistiming performance of the ToA estimator in a general Nakagamim channel. Analysis shows that the slope of the probability of...

The common signal processing problem of estimating some nonrandom parameters of a signal in additive noise is considered. The problem investigated in this paper is under what conditions an efficient estimator exists, i.e., an unbiased estimator with a variance equal to the Cramér–Rao lower bound (CRB). It is well known that if the signal is linear or, more generally, affine in the parameters an...