Preferred Language
Articles
/
joe-1095
Pilot Based Channel Estimation and Synchronization in OFDM System

Channel estimation and synchronization are considered the most challenging issues in Orthogonal Frequency Division Multiplexing (OFDM) system. OFDM is highly affected by synchronization errors that cause reduction in subcarriers orthogonality, leading to significant performance degradation. The synchronization errors cause two issues: Symbol Time Offset (STO), which produces inter symbol interference (ISI) and Carrier Frequency Offset (CFO), which results in inter carrier interference (ICI). The aim of the research is to simulate Comb type pilot based channel estimation for OFDM system showing the effect of pilot numbers on the channel estimation performance and propose a modified estimation method for STO with less number of pilot to mitigate ISI effect. Channel estimation is simulated for different pilot number with 16QAM modulation in Ped-A Rayleigh channel. The STO effect assumed less than the cyclic prefix length to minimize ISI and maintain the orthogonality between subcarriers. The simulation results show that the high number of pilots are needed to achieve good channel estimation in case no synchronization used while similar results are achieved with smaller number of pilots if the propose modification on the synchronization method are used aligned with the channel estimation. The proposed system is evaluated in terms of BER and SNR.

Crossref
View Publication Preview PDF
Quick Preview PDF
Publication Date
Tue Dec 01 2020
Journal Name
Systemic Reviews In Pharmacy
Scopus (1)
Scopus
Publication Date
Tue Jan 08 2019
Journal Name
Iraqi Journal Of Physics
Charge density distributions and electron scattering form factors of 19F, 27Al and 25Mg nuclei

An effective two-body density operator for point nucleon system folded with two-body correlation functions, which take account of the effect of the strong short range repulsion and the strong tensor force in the nucleon-nucleon forces, is produced and used to derive an explicit form for ground state two-body charge density distributions (2BCDD's) and elastic electron scattering form factors F (q) for 19F, 27Al and 25Mg nuclei. It is found that the inclusion of the two-body short range correlations (SRC) has the feature of reducing the central part of the 2BCDD's significantly and increasing the tail part of them slightly, i.e. it tends to increase the probability of transferring the protons from the central region of the nucleus towards

... Show More
Crossref
View Publication Preview PDF
Publication Date
Thu Apr 11 2024
Journal Name
Euphrates Journal Of Agriculture Science
Publication Date
Sat Jan 01 2022
Journal Name
Euphrates Journal Of Agricultural Science
Publication Date
Mon Jul 31 2017
Journal Name
Journal Of Engineering
View Publication Preview PDF
Publication Date
Sun Jun 01 2014
Journal Name
Baghdad Science Journal
Study of Fatigue and Bending Properties For Epoxy / Kevlar - Glass Fibers and Hybrid Composite

In this research a study of the effect of quality, sequential and directional layers for three types of fibers are:(Kevlar fibers-49 woven roving and E- glass fiber woven roving and random) on the fatigue property using epoxy as matrix. The test specimens were prepared by hand lay-up method the epoxy resin used as a matrix type (Quick mast 105) in prepared material composit . Sinusoidal wave which is formed of variable stress amplitudes at 15 Hz cycles was employed in the fatigue test ( 10 mm )and (15mm) value 0f deflection arrival to numbers of cycle failure limit, by rotary bending method by ( S-N) curves this curves has been determined ( life , limit and fa

... Show More
Crossref
View Publication Preview PDF
Publication Date
Mon Jan 01 2018
Journal Name
Asian Journal Of Microbiology, Biotechnology & Environmental Sciences
Scopus
Publication Date
Thu Jan 20 2022
Journal Name
Tikrit Journal Of Agriculture Sciences
Publication Date
Tue Sep 11 2018
Journal Name
Iraqi Journal Of Physics
Preparation and study the structure of pure and impure barium titanate with Mg2+ ion

Pure and doped barium titanate with Mg2+ ion at two molar ratios x= (5%, 10%) mol. has been synthesized by solid state reaction technique. The powders sintered at two temperatures (1000 °C and 1400 °C). An XRD technique was used in order to study the crystal structure of pure and doped barium titanate, which confirmed the formation of the tetragonal phase of BaTiO3, and then calculate the lattice parameters of pure and doped barium titanate, the addition of magnesium ion Mg2+ can lead to decreases lattice parameters.

Crossref
View Publication Preview PDF
Publication Date
Sun Feb 06 2022
Journal Name
Egyptian Journal Of Chemistry
Scopus (7)
Scopus Clarivate Crossref
View Publication