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.
Experimental results on harmonic distortions in 13.56 MHz RF Argon glow discharge using different grounded electrodes areas and electrodes spacing are presented. The experiment is carried out at four pressure values. RF power values used are between 20 and 90 watts. The results indicate significant increase in distortions at two specific values of the cone angle enclosing the two electrodes within its geometrical volume. The computation of the cone head angle gave the symmetry discharge or asymmetry as well as when the angle is small the condition is near symmetry discharge associated with decrease in the nonlinearity.
In recent years, the field of research around the congestion problem of 4G and 5G networks has grown, especially those based on artificial intelligence (AI). Although 4G with LTE is seen as a mature technology, there is a continuous improvement in the infrastructure that led to the emergence of 5G networks. As a result of the large services provided in industries, Internet of Things (IoT) applications and smart cities, which have a large amount of exchanged data, a large number of connected devices per area, and high data rates, have brought their own problems and challenges, especially the problem of congestion. In this context, artificial intelligence (AI) models can be considered as one of the main techniques that can be used to solve ne
... Show MoreThere are numerous bidirectional interactions between the reproductive system and the liver. Sex steroids regulate metabolic health through signaling effects in both peripheral and central metabolic tissues, including adipose tissue, liver, skeletal muscle, and brain, and have a role in the etiology of structural and functional liver diseases. Blood samples were obtained from 90 healthy women (control group) and 90 women that have hormonal changes (patients’ group). The levels of reproductive hormones (follicle stimulation hormone/FSH, luteinizing hormone/LH, estradiol/E2, progesterone/P4) were measured by using fully automated Cobas E411, whereas those of liver enzymes (alanine transaminase /ALT, aspartate aminotransferase/AST, a
... Show MoreForty six Iraqi women with PCOS were involved in this study . They were treated with metformin alone and with antioxidant agents (vitamin E or C).It was found that all patients who treated with metformin or with combination of metformin with antioxidant agents showed significant decrease in hirsutism score. The treatment of metformin with antioxidant agents is of great benefit in treatment of hirsutism in PCOS due to that there was no worsening effect after treatment. This may indicate that antioxidant agents may participate in alleviation of hirsutism so it can be said that oxidative stress may play an important role in developing of hirsutism in PCOS.
Background: Diabetic neuropathy can affect any peripheral nerve, including sensory neurons, motor neurons, and the autonomic nervous system. Therefore, diabetic neuropathy has the potential to affect essentially any organ and can affect parts of the nervous system like the optic nerve, spinal cord, and brain. In addition, chronic hyperglycemia affects Schwann cells, and more severe patterns of diabetic neuropathy in humans involve demyelization. Schwann cell destruction might cause a number of changes in the axon. study aims to evaluate serum myelin protein level as a predicting marker in the diagnosis of diabetic neuropathy and to prevent early neuropathy complications of type 2 diabetes.
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... Show MoreThe study aimed to identify Human Papillomavirus (HPV) and its genotypes prevalent among Iraqi women. They collected 89 cervical swab samples from diagnosed patients at Baghdad Teaching Hospital's Early Detection Clinic. Using PCR technique on 19 samples, they found HPV16 (57.89%) and HPV6 (10.52%) genotypes, while HPV-11, 18, and 45 were absent. HPV 16 and HPV 6 were common in cervical cancer among Iraqi women. Sequencing revealed nucleic acid variants in HPV-6 (124A>C) and HPV-16 (225G>T) E6 genes, resulting in silent effects on the encoded protein. These changes didn't alter amino acid residues (p.74I= and p.L117=). Phylogenetic analysis showed substantial distances between their samples and other viral types, indicating di
... Show MoreAbstract: The aim of the present work is to measure radon concentration in wood. Solid state nuclear track detectors of type CR – 39 was used as measurement device. Eight different samples of imported and local wood were collected from markets. Samples were grinded, dried in order to measure radon concentrations in it. Cylindrical diffusion tube was used as detection technique. Results show that the higher concentration was in Iraqi sample 1 which recorded (14.02 ± 0.9) Bq / m3, while the less was in Emirates Sample which recorded (5.35 ± 1.2) Bq / m3. From the present work, all wood samples were with lowest concentrations of radon gas than other building materials.
Background: Polycystic ovary syndrome (PCOS) is the most common endocrine abnormality in women, there is an increasing evidence for an oxidative stress in PCOS that induce genomic and mitochondrial deoxyribonucleic acid damage that leads directly to reduced fertility. The objectives of this study are to assess and compare the periodontal health status by measuring clinical periodontal parameters (PLI, GI and BOP)as well as serum levels of superoxide dismutase at gingivitis ,gingivitis with PCOS and healthy periodontium groups, then correlate between clinical and biochemical parameters. Materials and Methods: 60 females with an age range between (25-40) years old had been tested and divided into3 groups ,the control group consists of (20) f
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