7,500 research outputs found
A Survey of Air-to-Ground Propagation Channel Modeling for Unmanned Aerial Vehicles
In recent years, there has been a dramatic increase in the use of unmanned
aerial vehicles (UAVs), particularly for small UAVs, due to their affordable
prices, ease of availability, and ease of operability. Existing and future
applications of UAVs include remote surveillance and monitoring, relief
operations, package delivery, and communication backhaul infrastructure.
Additionally, UAVs are envisioned as an important component of 5G wireless
technology and beyond. The unique application scenarios for UAVs necessitate
accurate air-to-ground (AG) propagation channel models for designing and
evaluating UAV communication links for control/non-payload as well as payload
data transmissions. These AG propagation models have not been investigated in
detail when compared to terrestrial propagation models. In this paper, a
comprehensive survey is provided on available AG channel measurement campaigns,
large and small scale fading channel models, their limitations, and future
research directions for UAV communication scenarios
Comparative study of Radio Mobile and ICS Telecom propagation prediction models for DVB-T
In this paper, a comparative study between the results of a measurement campaign conducted in northern Greece and simulations performed with Radio Mobile and ICS Telecom radio planning tools is performed. The DVB-T coverage of a transmitting station located near the city of Thessaloniki is
estimated using three empirical propagation models (NTIA-ITS Longley Rice, ITU-R P.1546 and Okumura-Hata-Davidson) and one deterministic model (ITU-R 525/526). The best results in terms of minimum average error and standard deviation are obtained using the deterministic model and the NTIA-ITS
Longley Rice empirical model. In order to improve the results, the tuning options available in the ICS Telecom software are used on the Okumura-Hata-Davidson model, leading to a significant
increase in accuracy
Predicting the statistics of wave transport through chaotic cavities by the Random Coupling Model: a review and recent progress
In this review, a model (the Random Coupling Model) that gives a statistical
description of the coupling of radiation into and out of large enclosures
through localized and/or distributed channels is presented. The Random Coupling
Model combines both deterministic and statistical phenomena. The model makes
use of wave chaos theory to extend the classical modal description of the
cavity fields in the presence of boundaries that lead to chaotic ray
trajectories. The model is based on a clear separation between the universal
statistical behavior of the isolated chaotic system, and the deterministic
coupling channel characteristics. Moreover, the ability of the random coupling
model to describe interconnected cavities, aperture coupling, and the effects
of short ray trajectories is discussed. A relation between the random coupling
model and other formulations adopted in acoustics, optics, and statistical
electromagnetics, is examined. In particular, a rigorous analogy of the random
coupling model with the Statistical Energy Analysis used in acoustics is
presented.Comment: 32 pages, 9 figures, submitted to 'Wave Motion', special issue
'Innovations in Wave Model
Wave modelling - the state of the art
This paper is the product of the wave modelling community and it tries to make a picture of the present situation in this branch of science, exploring the previous and the most recent results and looking ahead towards the solution of the problems we presently face. Both theory and applications are considered.
The many faces of the subject imply separate discussions. This is reflected into the single sections, seven of them, each dealing with a specific topic, the whole providing a broad and solid overview of the present state of the art. After an introduction framing the problem and the approach we followed, we deal in sequence with the following subjects: (Section) 2, generation by wind; 3, nonlinear interactions in deep water; 4, white-capping dissipation; 5, nonlinear interactions in shallow water; 6, dissipation at the sea bottom; 7, wave propagation; 8, numerics. The two final sections, 9 and 10, summarize the present situation from a general point of view and try to look at the future developments
Terahertz Wireless Channels: A Holistic Survey on Measurement, Modeling, and Analysis
Terahertz (0.1-10 THz) communications are envisioned as a key technology for
sixth generation (6G) wireless systems. The study of underlying THz wireless
propagation channels provides the foundations for the development of reliable
THz communication systems and their applications. This article provides a
comprehensive overview of the study of THz wireless channels. First, the three
most popular THz channel measurement methodologies, namely, frequency-domain
channel measurement based on a vector network analyzer (VNA), time-domain
channel measurement based on sliding correlation, and time-domain channel
measurement based on THz pulses from time-domain spectroscopy (THz-TDS), are
introduced and compared. Current channel measurement systems and measurement
campaigns are reviewed. Then, existing channel modeling methodologies are
categorized into deterministic, stochastic, and hybrid approaches.
State-of-the-art THz channel models are analyzed, and the channel simulators
that are based on them are introduced. Next, an in-depth review of channel
characteristics in the THz band is presented. Finally, open problems and future
research directions for research studies on THz wireless channels for 6G are
elaborated.Comment: to appear in IEEE Communications Surveys and Tutorial
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