Abstract
The clustered delay line channel model, in which each cluster consists of many rays, is widely used for link-level evaluations in mobile communications. Multiple parameters of each ray, including the delay, amplitude, cross-polarization ratio (XPR), initial phases of four polarization combinations, and the azimuth and elevation angles of arrival and departure, must be known and 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. Based on the broadband extended array response of an electromagnetic vector antenna array, a new subspace estimation method is proposed to resolve a large number of rays. The inter-element spacing of the array can be greater than half the carrier wavelength, which reduces inter-element coupling and simplifies the array design, especially for millimeter-wave bands. The delay of each cluster is first estimated using the reference antenna element. Next, two-dimensional angles of every ray are estimated using the classic rank-deficient multiple signal classification algorithm. Finally, the initial phases, XPR, and amplitude of every ray are estimated. Simulation results validate the proposed method.
Highlights
The performance of wireless transmission in mobile communication systems is directly dependent on the channel propagation characteristics
The number of rays in one cluster is greater than the number of antenna elements, which is a common difficulty in channel parameter estimation.The proposed Broadband extended array response (BEAR)-based method utilizes the response in the space-frequency-polarization (SFP) domain to solve this problem
For a D-electromagnetic vector antenna (EMVA) array (D-electromagnetic vector antenna array (EMVAA)), the dipoles and loops are arranged in different directions, so each element of a distributed EMVA (D-EMVA) has a unique antenna gain
Summary
The performance of wireless transmission in mobile communication systems is directly dependent on the channel propagation characteristics. Increasing interest in polarized channel modeling and measurement, especially for multipolarized MIMO systems [10]–[13] Multiparameter estimation methods, such as maximum likelihood (ML) algorithm [14], multiple signal classification (MUSIC) [15], estimation of signal parameters via rotational invariance techniques (ESPRIT) and space-alternating generalized expectation-maximization (SAGE) [16], [17], have been investigated intensively in unipolarized array signal processing. The BEAR-based subspace estimation method is proposed to estimate the delay, 2D AoD, 2D AoA, initial phases of the four polarization combination state, amplitude and XPR in multipath environments using a multipolarized antenna array (EMVAA). The number of rays in one cluster is greater than the number of antenna elements, which is a common difficulty in channel parameter estimation.The proposed BEAR-based method utilizes the response in the space-frequency-polarization (SFP) domain to solve this problem.
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