Broadband Extended Array Response-Based Subspace Multiparameter
Estimation Method for Multipolarized Wireless Channel Measurements
Abstract
The clustered delay line channel model, in which each cluster consists
of a number of rays, is widely used for link-level evaluations in mobile
communications. Multiple parameters of each ray, including delay,
amplitude, cross polarization ratio (XPR), initial phases of four
polarization combinations and the azimuth and elevation angles of
arrival and departure, shall be known. These parameters are measured
using a channel sounder. The number of rays in every cluster is usually
greater than the number of elements in the antenna array of the channel
sounder, which represents a challenging issue in multipolarized channel
measurements. A new subspace estimation method based on the broadband
extended array response of an electromagnetic vector antenna array is
proposed to resolve a large number of rays. The interelement spacing of
the array can be greater than half the carrier wavelength, which reduces
interelement coupling and simplifies the array design, especially for
millimeter wave bands. First, the delay of each cluster is estimated
using the reference antenna element. Then, the 2D angles of every ray
are estimated using the classic rank-deficient multiple signal
classification (MUSIC). Lastly, the initial phases, XPR and amplitude of
every ray is estimated. Simulation results validate the proposed method.