RESUMO
Corrections are given for errors in the presentation of equations in J. Opt. Soc. Am. A34, 1187 (2017)JOAOD60740-323210.1364/JOSAA.34.001187.
RESUMO
In this work, the channel characterization in terms of large-scale propagation, small-scale propagation, statistical and interference analysis of Fifth-Generation (5G) Millimeter Wave (mmWave) bands for wireless networks for 28, 30 and 60 GHz is presented in both an outdoor urban complex scenario and an indoor scenario, in order to consider a multi-functional, large node-density 5G network operation. An in-house deterministic Three-Dimensional Ray-Launching (3D-RL) code has been used for that purpose, considering all the material properties of the obstacles within the scenario at the frequency under analysis, with the aid of purpose-specific implemented mmWave simulation modules. Different beamforming radiation patterns of the transmitter antenna have been considered, emulating a 5G system operation. Spatial interference analysis as well as time domain characteristics have been retrieved as a function of node location and configuration.
RESUMO
Underwater optical wireless communications (UOWC) performance is affected by turbulence. However, not much research has been carried out to estimate the probability density function (PDF) of the received optical power. In this paper, we investigate the effect of turbulence on the UOWC system using a new experimental setup with a variable link span in a water pool. Different turbulence levels are created by changing the temperature and the rate of an injected water flow in the pool water to obtain the PDF. Results show that lognormal distribution closely matches the measured PDF for a range of link spans. In UOWC systems, the link span is one of the main factors influencing fluctuations of the received optical power, and it has not been thoroughly investigated. In this work, the scintillation index and turbulence-induced power loss are obtained for a range of turbulence strengths and transmission link spans. Finally, we show that there is a good agreement between the experimental and simulated results.
RESUMO
Turbulence affects the performance of underwater wireless optical communications (UWOC). Although multiple scattering and absorption have been previously investigated by means of physical simulation models, still a physical simulation model is needed for UWOC with turbulence. In this paper, we propose a Monte Carlo simulation model for UWOC in turbulent oceanic clear water, which is far less computationally intensive than approaches based on computational fluid dynamics. The model is based on the variation of refractive index in a horizontal link. Results show that the proposed simulation model correctly reproduces lognormal probability density function of the received intensity for weak and moderate turbulence regimes. Results presented match well with experimental data reported for weak turbulence. Furthermore, scintillation index and turbulence-induced power loss versus link span are exhibited for different refractive index variations.
RESUMO
To aid in the development of a long-range subcutaneous radio frequency identification tag to monitor the fate of sea lion pups, the dielectric properties of the cranial skin of young female otariids, and possible test subjects of similar size and age, or pigs (Sus scrofa) and sheep (Ovis aries) were obtained over a frequency range of 0.1-10 GHz at the base of their heads where the tag will be implanted. The resulting curves were similar in shape to adult human skin data, but the values were generally lower. Between subjects, variations were noted in all the species. Circuitry for the RF-ID tag is being designed to account for antenna detuning as a result of the lossy media or skin and the variation in dielectric properties.