42 research outputs found
A Framework for Developing and Evaluating Algorithms for Estimating Multipath Propagation Parameters from Channel Sounder Measurements
A framework is proposed for developing and evaluating algorithms for
extracting multipath propagation components (MPCs) from measurements collected
by channel sounders at millimeter-wave frequencies. Sounders equipped with an
omnidirectional transmitter and a receiver with a uniform planar array (UPA)
are considered. An accurate mathematical model is developed for the spatial
frequency response of the sounder that incorporates the non-ideal cross-polar
beampatterns for the UPA elements. Due to the limited Field-of-View (FoV) of
each element, the model is extended to accommodate multi-FoV measurements in
distinct azimuth directions. A beamspace representation of the spatial
frequency response is leveraged to develop three progressively complex
algorithms aimed at solving the singlesnapshot maximum likelihood estimation
problem: greedy matching pursuit (CLEAN), space-alternative generalized
expectationmaximization (SAGE), and RiMAX. The first two are based on purely
specular MPCs whereas RiMAX also accommodates diffuse MPCs. Two approaches for
performance evaluation are proposed, one with knowledge of ground truth
parameters, and one based on reconstruction mean-squared error. The three
algorithms are compared through a demanding channel model with hundreds of MPCs
and through real measurements. The results demonstrate that CLEAN gives quite
reasonable estimates which are improved by SAGE and RiMAX. Lessons learned and
directions for future research are discussed.Comment: 17 page
Simplified Ray Tracing for the Millimeter Wave Channel: A Performance Evaluation
Millimeter-wave (mmWave) communication is one of the cornerstone innovations
of fifth-generation (5G) wireless networks, thanks to the massive bandwidth
available in these frequency bands. To correctly assess the performance of such
systems, however, it is essential to have reliable channel models, based on a
deep understanding of the propagation characteristics of the mmWave signal. In
this respect, ray tracers can provide high accuracy, at the expense of a
significant computational complexity, which limits the scalability of
simulations. To address this issue, in this paper we present possible
simplifications that can reduce the complexity of ray tracing in the mmWave
environment, without significantly affecting the accuracy of the model. We
evaluate the effect of such simplifications on link-level metrics, testing
different configuration parameters and propagation scenarios.Comment: 6 pages, 6 figures, 1 table. This paper has been accepted for
presentation at ITA 2020. (c) 2020 IEEE. Please cite it as: M. Lecci, P.
Testolina, M. Giordani, M. Polese, T. Ropitault, C. Gentile, N. Varshney, A.
Bodi, M. Zorzi, "Simplified Ray Tracing for the Millimeter Wave Channel: A
Performance Evaluation," Information Theory and Applications Workshop (ITA),
San Diego, US, 202
Methodology for Benchmarking Radio-Frequency Channel Sounders through a System Model
Development of a comprehensive channel propagation model for high-fidelity design and deployment of wireless communication networks necessitates an exhaustive measurement campaign in a variety of operating environments and with different configuration settings. As the campaign is time-consuming and expensive, the effort is typically shared by multiple organizations, inevitably with their own channel-sounder architectures and processing methods. Without proper benchmarking, it cannot be discerned whether observed differences in the measurements are actually due to the varying environments or to discrepancies between the channel sounders themselves. The simplest approach for benchmarking is to transport participant channel sounders to a common environment, collect data, and compare results. Because this is rarely feasible, this paper proposes an alternative methodology - which is both practical and reliable - based on a mathematical system model to represent the channel sounder. The model parameters correspond to the hardware features specific to each system, characterized through precision, in situ calibration to ensure accurate representation; to ensure fair comparison, the model is applied to a ground-truth channel response that is identical for all systems. Five worldwide organizations participated in the cross-validation of their systems through the proposed methodology. Channel sounder descriptions, calibration procedures, and processing methods are provided for each organization as well as results and comparisons for 20 ground-truth channel responses
A Comprehensive Evaluation of Indoor Ranging Using Ultra-Wideband Technology
Ultra-wideband technology shows promise for precision ranging due to its fine time resolution to resolve multipath fading and the presence of lower frequencies in the baseband to penetrate walls. While a concerted effort has been conducted in the extensive modeling of the indoor UWB channel in recent years, to our knowledge only two papers have reported ranging performance, but for limited range and fixed bandwidth and center frequency. In principle, boosting power can guarantee connectivity between transmitter and receiver, but not precision due to the distorting effects of walls and other objects in the direct path. In order to gauge the limits of UWB ranging, we carry out 5000 measurements up to an unprecedented 45 m in non-line-of-sight conditions in four separate buildings with dominant wall material varying from sheet rock to steel. In addition, we report performance for varying bandwidth and center frequency of the system
A Comprehensive Evaluation of Indoor Ranging Using Ultra-Wideband Technology
<p/> <p>Ultra-wideband technology shows promise for precision ranging due to its fine time resolution to resolve multipath fading and the presence of lower frequencies in the baseband to penetrate walls. While a concerted effort has been conducted in the extensive modeling of the indoor UWB channel in recent years, to our knowledge only two papers have reported ranging performance, but for limited range and fixed bandwidth and center frequency. In principle, boosting power can guarantee connectivity between transmitter and receiver, but not precision due to the distorting effects of walls and other objects in the direct path. In order to gauge the limits of UWB ranging, we carry out 5000 measurements up to an unprecedented 45 m in non-line-of-sight conditions in four separate buildings with dominant wall material varying from sheet rock to steel. In addition, we report performance for varying bandwidth and center frequency of the system.</p