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.
Modern American elegy reveals a change in the attitude of mourning from the traditional lamenting approach to some antielegiac attitudes towards the mourned figure. Many American poets have lamented the pass away of the stately figure of the father. However, some poets attack their dead father, and ridiculed him in a poem that is intended to be an elegy, instead of showing passion, homage and love to him. In this regard, two poetic attitudes to the father can be traced in modern American poetry. The first one takes the form of tributes and praise, offering great admiration, compassion, and love for the father. For these poets, a father is an inspiration. The second voice develops some anger and contempt against the patriarchal authority emb
... Show MoreThe research aims to identify the administrative skills and their role in institutional performance, and used the descriptive approach in a survey style and correlational relations to suit the nature of the problem to be studied.The research community was identified with the directors of sports activity in the Iraqi universities in a deliberate manner, and their number is (134) directors, where two scales (administrative skills and institutional performance) were used and the two scales were distributed to the above-mentioned sample in order to obtain answers that meet the required and representative sample of the community on the day 3/12/2021. The answers to all the statements were completed and after processing the results statistically
... Show MoreInformation pollution is regarded as a big problem facing journalists working in the editing section, whereby journalistic materials face such pollution through their way across the editing pyramid. This research is an attempt to define the concept of journalistic information pollution, and what are the causes and sources of this pollution. The research applied the descriptive research method to achieve its objectives. A questionnaire was used to collect data. The findings indicate that journalists are aware of the existence of information pollution in journalism, and this pollution has its causes and resources.
Walt Whitman adds a poetic twist to the relationship of man’s body, soul with the universe. His inspiration in writing his elegy, "When Lilacs Last in the Dooryard Bloom'd," draws on aesthetico-political resources. Major amongst these is his leaning towards the American Transcendentalist idea of the "Over-Soul". The basic topoi in his poems is thus his identification of nature with the soul of man. The idea of the Over-Soul sheds light on the three stages of human loss: suffering, despair, and compensation. Whitman witnessed two political events, the outbreak of the civil war and Abraham Lincoln's death, which were of a particular importance to his life and work: they helped him shape a form and thematic concerns of his own. Buil
... Show MoreTo identify the fungi associated with water hyacinth (Eichhornia crassipes [Mart.] Solms), an aquatic weed, which presents in Tigris river from Baghdad south ward. Five regions from middle and south of Iraq (Al-Noumanya, Saeid Bin-Jubier, Al-Azizia, Al-Reyfay and Al-Hay) were selected for this study. Twelve fungal species were isolated. Alternaria alternata, Acremonium sp and Cladsporium herbarum, were the most frequently species (91.66 % ,50 % and 25 %) respectively. The fungi Alternaria alternata, Acremonium sp. and Phoma eupyrena were more aggressive to water hyacinth as (91.66%,83,33%, and 75%) in pathogenicity test.
The aim of the research is to demonstrate the impact of organizational diversity management on achieving success, The problem of research is to create an appropriate work environment that stimulates everyone regardless of each dimension of diversity, So as to reach the best levels of success, The importance of research is to identify how the organization in question can manage organizational diversity effectively and contribute to its success, The research started from two main hypotheses which were derived from sub-hypotheses to identify the correlation and influence between the search variables by analyzing the answers of the research sample which included (81)
... Show MoreComparative Study Between Glimepiride and Glibenclamide in the Treatment of Type 2 Diabetic Patients in Al-Yarmouk Hospital
The current research aims to identify the Impact of strategy of modeling in the of deductive thinking and the attitvde towards mathematics among students in the high school stage
through check the following hypotheses:
1.There is no difference statistically significant at the level (0.05) between the scores mean of the experimental group students who have studied according to the modeling strategy and scores of control group students who have studied according to ordinary method in deductive thinking.
2.
... Show MoreIn this study, the stable isotop 18O and 2H has been used to investigate the interaction of surface water (SW), and groundwater (GW) in Al-Taji district/ Northern Baghdad for two seasons (March and August 2022). 16 Samples were collected from water resources in the Al-Taji district (Tigris channel, Tigris River, and groundwater), in each season water samples from 8 Tigris channel, 5 drilled wells, and 3 Tigris River were taken for the analysis of the isotopes 18O and 2H. The average analysis results of 18O and 2H in the Tigris channel, Tigris River, and groundwater were found to be -3.435‰ and -18.6094‰, -2.07167‰ and -17.81‰, -4.125‰ and -34.707‰ respectively. The results, generally, show a comparable range of isotope c
... Show MoreDetergent is one of the pollutants that poses significant threats to ecological systems. Detergents can also dissolve in wastewater and negatively impact the efficiency of wastewater treatment facilities. They are used for a variety of functions, most notably hygiene, and are an integral aspect of human life. This means that there are a variety of routes by which detergent components can reach the environment. In this Study, twenty-three detergent samples from local markets in Baghdad. The aim of this study is to investigate the concentration of heavy metals Cobalt (Co), Chromium (Cr),Lead (Pb),Zinc (Zn), Iron (Fe) and Cadmium (Cd) in some detergents using Atomic Absorption Spectrophotometer. The results of the concentration of heavy elemen
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