Visible Light Communication (VLC) has emerged as a powerful technique for wireless communication systems. Providing high data rate and increasing capacity are the major problems in VLC. Recent evidence suggests that Multiple Input Multiple Output (MIMO) technique can offers improved data rates and increased link range. This paper describes the design and implementation of visible light communication system in indoor environment exploring the benefits of MIMO. The specific objective of this research was to implement a 4× 4 Multiple Input (LEDs) Multiple Output (photodetectors)-VLC communication system, where a 16 white power LEDs in four arrays are setting up at transmitter and four RX modules are setting up at receiver side without the need for additional power or bandwidth as well as analyze a mathematical model for a VLC-× 4 MIMO with different modes such as the suitable angles to cover the entire room. The research designs practically an electronic circuit for the transmitter and receiver with inexpensive components. The power distribution of different propagation modes is calculated for Single Input Single Output (SISO) and MIMO channels in typical room dimensions. The results in this paper indicate that the power is distributed uniformly for entire room when implemented VLC-MIMO as compared to VLC-SISO. Furthermore, a 4× 4 MIMO implementing VLC is compared in term of BER vs. SINR with SISO communication system for both Line of Sight (LOS) and Non Line of Sight (NLOS) propagation modes. Comparing the two results of LOS and NLOS, it can be seen that a 4× 4 MIMO implementing VLC for LOS perform better …
The present paper analyzes the signal emitting from the Reticle during changing the spot size of laser falling on the disk and shows the optimum frequency and the amount of energy window in different patterns of modulator (Reticle). All results are obtained by establishing a special program named “Disk optical modulator version 3" using the language visual basic 6 ahich contains many parameters. All models of optical modulator consist of twenty sectors, ten sectors are opaque and other ten sectors are transmitted for the laser. The number of sectors depends on several factors as chopping frequency, power transparent and modulation transfer function. It has been demonstrated by simulations, the optimal
... Show MoreFilms of silver oxide of different thickness have been prepared by the chemical spray paralysis. Transmission and absorption spectra have recorded in order to study the effect of increasing thickness on some optical parameter such as reflectance, refractive index , and dielectric constant in its two parts . This study reveals that all these paramters affect by increasing the thickness .
In this paper we have studied the optical properties of CuBr thin
films. Different sample thicknesses have been prepared by using thermal evaporation technique with 14.4 runlsec as the average deposition rate and 1 00°C as the substrate temperature.
In this work, optical system with elliptical aperture using point spread function was studied. This is due to its comparison with an optical system with a circular aperture. The present work deals with the theoretical study of intensity distribution within the image. In this work, a special formula was derived which is called the point spread function (PSF) by using a pupil function technique. The work deals with the limited optical system diffraction only (ideal system), and the system with focal shift. Also a graphic relation was founded between eccentricity and the best of focal depth given to at least (80%) of intensity.
In this work the Aluminum plasma in Air produced by Nd: YAG pulsed laser, (λ = 1064 nm, τ = 6 ns) has been studied with a repletion rate of 10 Hz. The laser interaction in Al target (99.99%) under air atmosphere generates plasma, which is produced at room temperature; with variation in the energy laser from 600-900 mJ. The electron temperature and the electron density have been determined by optical emission spectroscopy and by assuming a local thermodynamic equilibrium (LTE) of the emitting species. Finally the electron temperature was calculated by the Boltzmann plot from the relative intensities of spectral lines and electron density was calculated by the Stark-broadening of emission line.
In this research , the structural and optical properties of pure of cadmium oxide, pure (CdO) were studided thin films in a thermal evaporation in a vacuum depositing metal cadmium pure rules of the glass at room temperature (300K) and thickness (300 ± 20nm) and the time of deposition (1.25sec) was oxidation of thin films cadmium (Cd) record temperature (673k) for a period of one hour to the presence of air optical energy gap for direct electronic transitions were calculated (permitted) as a function of absorption coefficient and permeability and reversibility by recording the spectrum absorbance and permeability of the membrane the record
... Show MoreRecords of two regionalized variables were processed for each of porosity and permeability of reservoir rocks in Zubair Formation (Zb-109) south Iraq as an indication of the most important reservoir property which is the homogeneity , considering their important results in criterion most needed for primary and enhanced oil reservoir .Z and F tests that were calculated for the two above mentioned properties of pair units of Zubair Formation have shown the difference in depositional energy and different diagenesis between units IL and AB , DJ and AB , and the similarity in grains size , sorting degree , depositional environment and pressure gradients between IL and AB units , LS and IL units ; also the difference in the properties above betw
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