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.
Subjects took physical fitness for health imposed on the area of research that have become an important and clear answer to the many problems resulting from the nature of dealing with modern life current actions that were needed to be hours of manual work has become accomplished by modern technology circumstance minutes, and mediated equipment And machinery. The lack of traffic rights and further burdens the intellectual and psychological pressures and the typical method of work has led to the identification of kinetic activity, thereby threatening public health in many ways stands at the forefront of these threats the problem of smoking, which causes many types of cancers, notably lung cancer. The most important reasons that led to This dr
... Show MoreVisceral leishmaniosis is one of the most fatal old-world neglected disease with estimated 90 thousand worldwide cases emerge each year. In Iraq, the cutaneous and visceral form are endemic but available chemotherapies are either toxic with diverse side effects, expensive available drugs or parasite …
Morphometric traits or body conformation traits also called linear body measurements are important in predicting marketing body weight especially for commercial breeders and producers. The total number of reared Domyati ducklings are 168 hatched, at marketing age (8 wks.) 44 brown and 14 white Domyati ducks were used to estimate the body weight and body measurements such as shank length (ShL), keel length (KL), body circumference (BC), breast length (BrL), breast width (BrW), beak width (BL), and body length (BL). Our results showed that there is no significant difference between both white and brown Domyati ducks for body measurements. There was high positive correlation among body weight and body measurements on both white and bro
... Show MoreIntroduction:Serratia marcescens is a gram-negative pathogen of many species. Its pathogenicity and survival are linked to its capacity to build biofilms as well as its strong inherent resistance to antimicrobials and cleaning agents. Objectives: To analyse the impact of glyceryl trinitrate (GTN) on the gene expression of QS-related genes (rssB, rsmA,and pigP) of S. marcescens. Methodology: The broth microdilution technique estimated the bactericidal effectiveness of glyceryl trinitrate. The presence of rssB, rsmA,and pigP in S. marcescens isolates was detected using PCR. qRT-PCR was used to assess the effect of GTN on rssB, rsmA,and pigPgene expression. Results: The results demonstrated that GTN has no effect on S. marcesce
... Show MoreThis study aimed to evaluate serum levels of steroid hormones and human chorionic gonadotropin (hCG) hormone in preeclamptic Iraqi pregnancies compared to those of healthy pregnancies.This study enrolled 120 pregnant women, divided into four groups:1. 30 healthy pregnant women.2. 37 pregnant women with mild preeclampsia3. 53 pregnant women with severe preeclampsia4. 90 pregnant women with preeclampsia Preeclamptic women and their severe cases but not mild cases had significantly (P<0.01) increased levels of serum hCG as compared with healthy pregnancies. By contrast, sera levels of estradiol were significantly (P<0.01) decreased in total preeclamptic groups and their severe cases but not in mild group as compared to healthy pregnant wome
... Show MoreDensities ρ and viscosities η for several concentrations of amino acids (Serine, Cysteine and Threonine) at different temperatures (298.15, 303.15 and 308.15K) have been measured. On the basis of these data, the apparent molal volumes v , partial molal volumes at infinite dilution v , slope Sv , Gibbs free energy of activation for viscous flow of solution ∆G1,2 and Jones – Dole Bcoefficients were calculated the nature of solute-solvent and solute-solute interactions have been discussed in terms of the values of v , v , Sv and B-coefficents
Based on the German language department’s theoretical and practical aspects as well as educational programs, the present study discusses the semantic relations in text sentences and their role in the science of translation. Through clarifying the semantic relationship between the text sentence and the methods used to express a news item, a situation or an occurrence and through the statement of the multiple theoretical semantic structures of the text’s construction and interrelation, a translator can easily translate a text into the target language.
It is known that language learners face multiple difficulties in writing and creating an inte
... Show MoreContemporary developments in various sciences and the impact of technological changes require an integrated vision of the activities and work of the organization in Iraq in light of the high costs of products and their low quality compared to imported products of high quality and low cost, and the need to use modern cost techniques based on a clear and specific philosophy that contributes to increasing the efficiency and effectiveness of management In the business environment and how it can contribute to reducing product costs and being environmentally friendly at the same time, it is no secret that the main goal of most organizations is to maximize profitability and reduce costs to the minimum, but this matter is not achieved autom
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