Gridless Joint Delay-DoA-Doppler Estimation Using OFDM Signals: A Multilevel Hankel Matrix Approach

This paper investigates the problem of joint es-timation of delay, direction of arrival (DoA), and Doppler when an orthogonal frequency-division multiplexing (OFDM) signal is used for probing. A gridless approach is taken where the above three parameters live on a continuous space rather than a discrete grid. A low-rank multilevel Hankel matrix is used to capture the underlying structure of the back-scattered signals. A convex optimization, termed as Hankel nuclear norm minimization (HNNM), is developed for denoising and parameter estimation, and solved by alternating direction method of multi-pliers (ADMM). Simulations demonstrate that HNNM is robust to noise, and can go beyond the minimum separation bound required by another gridless method atomic norm minimization.