A Survey of Dense Multipath and Its Impact on Wireless Systems

Jiang, Suying; Wang, Wei; Miao, Yang; Fan, Wei; Molisch, Andreas F.

doi:10.1109/ojap.2022.3168400

Cited by 17 publications

(14 citation statements)

References 157 publications

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“…In recent years, an extension of the channel model has been considered, that includes a DC [9], [51], [52]. The DC incorporates diffuse scattering as well as SCs that cannot be resolved with the finite aperture of the measurement equipment.…”

Section: A State Of the Artmentioning

confidence: 99%

Super-Resolution Estimation of UWB Channels Including the Dense Component—An SBL-Inspired Approach

Grebien,

Leitinger,

Witrisal

et al. 2024

IEEE Trans. Wireless Commun.

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In this paper, we present an iterative algorithm that detects and estimates the specular components (SCs) and estimates the dense component (DC) of single-input-multipleoutput (SIMO) ultra-wide-band (UWB) multipath channels. Specifically, the algorithm super-resolves the SCs in the delayangle-of-arrival domain and estimates the parameters of a parametric model of the delay-angle power spectrum characterizing the DC. Channel noise is also estimated. In essence, the algorithm solves the problem of estimating spectral lines (the SCs) in colored noise (generated by the DC and channel noise). Its design is inspired by the sparse Bayesian learning (SBL) framework. As a result the iteration process contains a threshold condition that determines whether a candidate SC shall be retained or pruned. By relying to results from extreme-value analysis the threshold of this condition is suitably adapted to ensure a prescribed probability of detecting spurious SCs. Studies using synthetic and real channel measurement data demonstrate the virtues of the algorithm: it is able to still detect and accurately estimate SCs, even when their separation in delay and angle is down to half the Rayleigh resolution limit (RRL) of the equipment; it is robust in the sense that it tends to return no more SCs than the actual ones. Finally, the algorithm is demonstrated to outperform a state-of-the-art super-resolution channel estimator in terms of robustness in the estimation of the amplitudes of specular components closely spaced in the dispersion domain.1 Super-resolution is the ability of an algorithm to resolve spectral lines even if the separation of their support in the dispersion domain is below the intrinsic resolution of the measurement equipment.

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Section: A State Of the Artmentioning

confidence: 99%

Super-Resolution Estimation of UWB Channels Including the Dense Component—An SBL-Inspired Approach

Grebien,

Leitinger,

Witrisal

et al. 2024

IEEE Trans. Wireless Commun.

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“…Physical models for wave propagation have been developed explicitly for this purpose, and typically models are employed in which the channel is characterized as a number of discrete Multipath Components (MPCs) originating at the transmitter and impinging upon the receiver [3]. Sometimes the concept of dense multipath [4] is also included in the model, in which one or more exponential functions in the time domain are also jointly considered. The modeling of these MPCs is typically done either with site-specific channel models (including ray models) where the complete wave trajectories are determined analytically, or alternatively the parameters of MPCs are treated stochasti-cally [5].…”

Section: Introductionmentioning

confidence: 99%

“…1 Polarization is omitted in this work, as in [4], for brevity, but could also be considered for clustering if desired.…”

Section: Introductionmentioning

confidence: 99%

Flexible Density-based Multipath Component Clustering Utilizing Ground Truth Pose

Whiton,

Chen,

Tufvesson

2023

2023 IEEE 98th Vehicular Technology Conference (VTC2023-Fall)

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Accurate statistical characterization of electromagnetic propagation is necessary for the design and deployment of radio systems. State-of-the-art channel models such as the Enhanced COST 2100 Channel Model utilize the concept of clusters of multipath components, and characterize channels by their inter-and intra-cluster statistics. Automatic clustering algorithms have been proposed in literature, but the subjective nature of the problem precludes any from being deemed objectively correct. In this paper, a new algorithm is proposed, based on density-reachability and ground truth receiver pose, with the explicit focus of extracting clusters for the purpose of channel characterization. Measurements of downlink signals from a commercial LTE base station by a passenger vehicle driving in an urban environment with a massive antenna array on the roof are used to evaluate the repeatability and intuitiveness of the proposed clustering algorithm.

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“…Among the high frequency approximation approaches, approximation in PO is made when determining the surface currents. [7], [17], [18] The geometry surface is divided into meshes that are much smaller compared to the wavelength and each mesh is considered as locally planar where reflection occurs according to GO. Instead of using Maxwell's equations that gives us the solution at any point in space, PO approach is used where it only gives solution in the lit region.…”

Section: Introductionmentioning

confidence: 99%

Simulation and Measurement Validation of a Finite-Length Cylindrical 3D UTD Model

Liu

Gong

Pollin

et al. 2022

IEEE Open J. Antennas Propag.

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In this paper we provide a modified 3D Uniform Theory of Diffraction (UTD) model for a finite-length cylinder, and validate the model by comparing to the simulation and the measured data. The presented finite-cylinder UTD model is adapted from the conventional infinite-cylinder model, and we additionally add edge diffraction occurring at the edge of the cap of the finite cylinder. The simulation reference is obtained from the CST simulation and the measurement reference is obtained from a vector network analyzer based channel sounder. From the numerical examples and analysis, it is shown that the modified model agrees well with the references and is more accurate than the conventional unmodified model. This study proves the importance of the edge diffraction field for finite-cylinder UTD solutions specially when 1) the transmitter and receiver are at different heights relative to the cylinder, and 2) one is below and the other is above the height of the cylinder.

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A Survey of Dense Multipath and Its Impact on Wireless Systems

Cited by 17 publications

References 157 publications

Super-Resolution Estimation of UWB Channels Including the Dense Component—An SBL-Inspired Approach

Super-Resolution Estimation of UWB Channels Including the Dense Component—An SBL-Inspired Approach

Flexible Density-based Multipath Component Clustering Utilizing Ground Truth Pose

Simulation and Measurement Validation of a Finite-Length Cylindrical 3D UTD Model

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