10,678 research outputs found
A cross-layer heuristic algorithm for addressing shadowing problem in optical attocell networks
The performance of visible light communication (VLC)-based optical attocell networks degrades due to shadowing caused by opaque objects. In order to improve reliability, we propose a cross-layer algorithm to find the optimal routing and resource allocation schemes when shadowing occurs. Simulation results show that the optimal scheme found by the proposed algorithm significantly improves the performance of optical attocell networks with one randomly shadowed link
Shadowing Effects on Vector Boson Production
We explore how nuclear modifications to the nucleon structure functions,
shadowing, affect massive gauge boson production in heavy ion collisions at
different impact parameters. We calculate the dependence of , and
production on rapidity and impact parameter to next-to-leading order in
Pb+Pb collisions at 5.5 TeV/nucleon to study quark shadowing at high . We
also compare our Pb+Pb results to the rapidity distributions at 14 TeV.Comment: 25 pages ReVTeX, 12 .eps figures, NLO included, version accepted for
publication in Physical Review
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
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