6 papers
Near-field channel estimation via wavefront parameterization
Heedong Do, Namyoon Lee, Angel Lozano
This paper deals with the estimation of multiantenna channels in the line-of-sight conditions that are prevalent in the near field. By expressing the curved wavefront as a polynomi…
Cramer-Rao Bound for Arbitrarily Constrained Sets
Heedong Do, Angel Lozano
This paper presents a Cramer-Rao bound (CRB) for the estimation of parameters confined to an arbitrary set. Unlike existing results that rely on equality or inequality constraints,…
Beamforming Gain with Nonideal Phase Shifters
Heedong Do, Angel Lozano
This research sets forth a universal framework to characterize the beamforming gain achievable with arbitrarily nonideal phase shifters. Precisely, the maximum possible shortfall r…
Optimum Discrete Beamforming via Minkowski Sum of Polygons
Heedong Do, Angel Lozano
This letter casts the problem of optimum discrete beamforming as the computation of the Minkowski sum of convex polygons, which is itself a convex polygon. The number of vertices o…
Multidimensional Polynomial Phase Estimation
Heedong Do, Namyoon Lee, Angel Lozano
An estimation method is presented for polynomial phase signals, i.e., those adopting the form of a complex exponential whose phase is polynomial in its indices. Transcending the sc…
Hybrid Arrays: How Many RF Chains Are Required to Prevent Beam Squint?
Heedong Do, Namyoon Lee, Robert W. Heath +1
With increasing frequencies, bandwidths, and array apertures, the phenomenon of beam squint arises as a serious impairment to beamforming. Fully digital arrays with true time delay…