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.
Abstract
Background: anabolic androgenic steroids (AASs) are becoming increasingly popular between bodybuilders and people who want to enhance their physiques. However, according to the rise of the Internet and laws prohibiting sales of these substances without prescription, the route of obtaining and administration practices have become more and more dangerous.
Objective: Anabolic-androgenic steroids represents a group of synthetic testosterone derivatives its play an important role in clinical treatment. These group of drugs are widely abused among the general public to increase lean body weight and improve athletic performance. It has been reported that AAS use can cause many adverse e
... Show MoreThe reciprocal relationship between the text and the mask in the printed product is one of the most important relationships that frame the level of communication between the appearance and the interior, although it is not cared for by some designers and publishing institutions. Therefore, the problem of research is determined by the following question (What is the dialectical relationship between the text and the mask in the literary books covers design?). The research aims to shed light on this problematic relationship at the level of reception and aesthetics at the same moment. The theoretical framework included two sections: the first (mask and text ... the concept and the mutual relationship), while the second section (trends in the
... Show MoreThe purpose of this research was to investigate the beneficial effects of phosphatidylcholine in reducing changes in both lipid and protein profiles in addition to atherogenic index in adult rats with fructose-induced metabolic syndrome. Thirty-six mature Wistar Albino female rats (Rattus norvegicus) (aged 12-15 weeks and weighing 200±10 g) were divided randomly into four groups (G1, G2, G3, and G4); then variable treatments were orally administered for 62 days as follows: G1 (Control group), received distilled water; G2, treated with phosphatidylcholine (PC) orally (1 g/kg BW); G3 (Fr), orally dosed with 40% fructose and 25% fructose mixed with drinking water; G4 (Fr+PC), were also intubated with 40% fr
... Show MoreObjective: The aim of this study was to formulate and in vitro evaluate fast dissolving oral film of practically insoluble bromocriptine mesylate to enhance its solubility and to improve its oral bioavailability by avoiding first pass effect as well as to produce an immediate release action of the drug from the film for an efficient management of diabetes mellitus type II in addition to an improvement of the patient compliance to this patient- friendly dosage form. Methods: The films were prepared by the solvent casting method using hydroxypropyl methylcellulose of grades (E3, E5, E15), polyvinyl alcohol (PVA), pectin and gelatin as film-forming polymers in addition to polyethene glycol 400 (PEG400), propylene glycol (PG) and glycerin were
... Show MoreVitamin E, having the well known antioxidant activity through scavenging free radicals و it occurs in several isomeric forms , these isomers have relatively different functions . One of these actions is related to its ability to inhibit platelets aggregation and hence thrombosis. The present study included a total number of apparently healthy 62 males . 11of them served as standard group , treated with 100 mg aspirin /day for more than one month . Another 31 subjects were randomly grouped into 5 groups that received different daily doses of α – tocopherol : 400 IU , 800 IU and 1200 IU for 2-6 months.The remainder ( 20 ) subjects served
... Show MoreIn the present work the clathrate hydrate dissociation enthalpies of refrigerant R134a+ water system, and R134a + water + salt system were determined. The heat of dissociation of three types of aqueous salts solutions of NaCl, KBr and NaF at three concentrations (0.09, 0.17and 0.26) mol·kg−1 for each salt type, were enthalpy measured. The Clapeyron equation was used tocalculate heat of dissociation of experimental data for binary and ternary system.In order to find the effect of compressibility factor on heat dissociation enthalpy, the study was conducted by using equation of state proposed by Peng and Robinson Stryjek-Vera (PRSV). The obtained results of dissociation enthalpy for binary system were (143.8) kJ.mol-1
... Show MorePhysiological status and litter size can indeed have a significant impact on ewes' hematological parameters, which are essential indicators of their health. Therefore, this study examined the hematological profiles of ewes during pregnancy with single and twins in the Awassi ewes. The present study involved 232 ewes in good health and at sexual maturity. Among them, 123 ewes had single pregnancies, while 109 ewes had twin pregnancies. The age range of the ewes included in the study was between 3.5 and 4.5 years. Hematological tests were conducted on the sheep's blood samples promptly following collection. The findings demonstrated variations in hematological parameters among pregnant
... Show MoreOrganism is considered one of the intellectual products that search for compatibility and harmony with the natural environment. Man has adopted on since the ancient times in choosing his residence through imitating nature such as animal burrows, hives, bird nests and others of the natural manifestations being spontaneous inspirations. With the development of the age, these concepts turned into an analysis that examines the philosophy that deals with the shapes and functions of various elements in the nature as a source of inspiration, and discusses the call for contemplation and achieving benefits physically and spiritually in line with the nature of the organic thought that seeks to keep up with modern technologies that are characterize
... Show MoreThis research aims to develop transdermal patches of Ondansetron hydrochloride (OSH) with different types of polymers, ethyl cellulose and, polyvinyl pyrrolidone k30 in a ratio (3:0.5,3:1,3:2,2:1,1:1) with propylene glycol 20%w/w as a plasticizer. Prepared transdermal patches were evaluated for physical properties. The compatibility between the drug and excipients was studied by Differential scanning calorimetry (DSC), where there is no interaction between the drug and polymers. From the statistical study, there is a statistical difference between all the prepared formulations p<0.05. In-vitro Release study of transdermal patches was performed by using a paddle over the disc. The release profile of OSH follow
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