Enhanced Air-Interfaces for Fifth Generation Mobile Broadband Communication

In broadband wireless multicarrier communication systems, intersymbol interference (ISI) and intercarrier interference (ICI) should be reduced. In orthogonal frequency division multiplexing (OFDM), the cyclic prefix (CP) guarantees to reduce the ISI interference. However, the CP reduces spectral and power efficiency. In this thesis, iterative interference cancellation (IIC) with iterative decoding is used to reduce ISI and ICI from the received signal in multicarrier modulation (MCM) systems. Alternative schemes as well as OFDM with insufficient CP are considered; filter bank multicarrier (FBMC/Offset QAM) and discrete wavelet transform based multicarrier modulation (DWT-MCM). IIC is applied in these different schemes. The required components are calculated from either the hard decision of the demapper output or the estimated decoded signal. These components are used to improve the received signal. Channel estimation and data detection are very important parts of the receiver design of the wireless communication systems. Iterative channel estimation using Wiener filter channel estimation with known pilots and IIC is used to estimate and improve data detection. Scattered and interference approximation method (IAM) preamble pilot are using to calculate the estimated values of the channel coefficients. The estimated soft decoded symbols with pilot are used to reduce the ICI and ISI and improve the channel estimation. The combination of Multi-Input Multi-Output MIMO and OFDM enhances the air-interface for the wireless communication system. In a MIMO-MCM scheme, IIC and MIMO-IIC-based successive interference cancellation (SIC) are proposed to reduce the ICI/ISI and cross interference to a given antenna from the signal transmitted from the target and the other antenna respectively. The number of iterations required can be calculated by analysing the convergence of the IIC with the help of EXtrinsic Information Transfer (EXIT) charts. A new EXIT approach is proposed to provide a means to define performance for a given outage probability on quasi-static channels

Performance Analysis of DoA Estimation for FDD Cell Free Systems Based on Compressive Sensing Technique

The concept of cell free (CF) massive MIMO systems is a prospective fifth generation communication technology that effort with base stations for the privilege of user-centric coverage. Most studies on the CF massive MIMO system in the past imply that systems that use time division duplexing (TDD), even despite the systems using frequency division duplex (FDD) predominate in today’s wireless communications. When the number of antennas increases in FDD systems, channel state information (CSI) collection and feedback overhead become major issues. In order to mitigate these issues, we make use of the condition that the so-called uplink and downlink multipath components are comparable. Base station takes use of the angle reciprocity may immediately obtain information on channel parameters from the uplink training signal. In this paper, for CF massive MIMO system based on FDD, we provide compressive sensing (CS) of directions of arrival (DoAs) estimation approach of access point cooperation based on the channel parameters. The suggested estimation approach outperforms the established subspace-based technique, according to simulation findings. Additionally, we showed that the results of our compressive sensing estimator against the conventional estimation method. The former demonstrates way far better outcome and performance accordingly than the latter

Partial Purification and Characterization of Exo-Polygalacturonase Produced by Penicillium oxalicum AUMC 4153

Pectinase enzymes are important industrial enzymes having considerable applications in several industries, especially in food processing. Pectinases contribute 25% of global food enzyme sales. Therefore, the demand for a commercial enzyme with desirable characteristics and low production costs has become one of the great targets. Hence, this study aims to produce exo-polygalacturonase (exo-PG) using local fungal isolate Penicillium oxalicum AUMC 4153 by utilizing sugar beet manufacturing waste (sugar beet pulp) as a sole raw carbon source under shaken submerged fermentation, which is purified and characterized to optimize enzyme biochemical properties for industrial application. The purity of the obtained exo-PG was increased by about 28-fold, and the final enzyme yield was 57%. The partially purified enzyme was active at a broad range of temperatures (30–60 °C). The optimum temperature and pH for the purified exo-PG activity were 50 °C and pH 5. The enzyme was stable at a range of pH 3 to 6 and temperature 30–50 °C for 210 min. The values for Km and Vmax were 0.67 mg/mL, with polygalacturonic acid as substrate and 6.13 µmole galacturonic acid/min/mg protein, respectively. It can be concluded that purified exo-PG production by P. oxalicum grown on sugar beet waste is a promising effective method for useful applications.</jats:p

Wavelet-OFDM vs. OFDM: Performance Comparison

International audienceWavelet-OFDM based on the discrete wavelet transform , has received a considerable attention in the scientific community, because of certain promising characteristics. In this paper, we compare the performance of Wavelet-OFDM based on Meyer wavelet, and OFDM in terms of peak-to-average power ratio (PAPR), bit error rate (BER) for different channels and different equalizers, complexity of implementation, and power spectral density. The simulation results show that, without decreasing the bandwidth efficiency, the proposed scheme based on Meyer Wavelet-OFDM, outperforms OFDM in terms of PAPR by up to 4.5 dB, and in terms of BER by up to 6.5 dB of signal to noise ratio when using the minimum mean-square error equalizer without channel coding, at the cost of a computational complexity increase

Modulation and performance of synchronous demodulation for speech signal detection and dialect intelligibility

Speech processing is one of the fundamental operations in computer science and it is particularly difficult to process and distinguish speech in different Arabic dialects when background noise is present. In any nation, communication skills are crucial. Pushing a button is all it takes for the typical person to make phone calls and leave voicemails but for telecommunications experts, the process is very different. We understand how communication actually works. The terms detection and demodulation are commonly used when addressing the full demodulation process. The procedures and circuits are substantially the same under both designations. As the name implies, demodulation is the opposite of modulation, which is applying a signal, such as an audio signal, to a carrier. The demodulation process isolates the output signal from the audio or other signal that was transmitted using amplitude shifts on the carrier. In this study, a system for distinguishing speech signals was developed using modulation and demodulation to transmit speech by extracting it from a variety of factors, the most significant of which is background noise in addition to a wide variety of dialects, which poses a significant challenge in speech processing. The proposed system was applied to a dataset that was created for a group of voices in different dialects, and by using important techniques, the noise accompanying the voices was deleted and then the voices were processed with other techniques such as modulation and demodulation to distinguish the dialect. The system has proven effective by distinguishing dialects

Fulminant Guillain–Barré Syndrome Post Hemorrhagic Stroke: Two Case Reports

Guillain–Barré syndrome (GBS) is an acute, immune-mediated inflammatory peripheral polyneuropathy characterized by ascending paralysis. Most GBS cases follow gastrointestinal or chest infections. Some patients have been reported either following or concomitant with head trauma, neurosurgical procedures, and rarely hemorrhagic stroke. The exact pathogenesis is not entirely understood. However, blood–brain barrier damage may play an essential role in triggering the autoimmune activation that leads to post-stroke GBS. Here, we present two cases of fulminant GBS following hemorrhagic stroke to remind clinicians to be aware of this rare treatable complication if a stroke patient develops unexplainable flaccid paralysis with or without respiratory distress

Concomitant Sub-Chronic Administration of Small-Size Gold Nanoparticles Aggravates Doxorubicin-Induced Liver Oxidative and Inflammatory Damage, Hyperlipidemia, and Hepatic Steatosis

This study examined the effect of gold nanoparticles (AuNPs) on doxorubicin (DOX)-induced liver damage and steatosis in rats and tested its effect mechanism. Wistar male rats were divided into four groups (each of eight rats) as control, AuNPs (50 µL of 10 nm), DOX (15 mg/kg; 3 mg/kg/week), and DOX + AuNPs-treated rats. DOX is known to induce fasting hyperglycemia and hyperinsulinemia in treated rats. Individual treatment of both DOX and AuNPs also promoted liver damage, increased circulatory levels of ALT and AST, and stimulated serum and liver levels of TGs, CHOL, LDL-c, and FFAs. They also stimulated MDA, TNF-α, and IL-6, reduced GSH, SOD, HO-1, and CAT, upregulated mRNA levels of Bax and caspases-3 and -8 and downregulated mRNA levels of Bcl2 in the livers of rats. However, while DOX alone reduced hepatic levels of PPARα, both AuNPs and DOX stimulated mRNA levels of SREBP1, reduced the mRNA, cytoplasmic and nuclear levels of Nrf2, and increased mRNA, cytoplasmic, and nuclear levels of NF-κB. The liver damage and the alterations in all these parameters were significantly more profound when both AuNPs and DOX were administered together. In conclusion, AuNPs exaggerate liver damage, hyperlipidemia, and hepatic steatosis in DOX-treated rats by activating SREBP1 and NF-κB and suppressing the Nrf2/antioxidant axis