193 research outputs found

    Aspects of capacity enhancement techniques in cellular networks

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    Frequency spectrum is the scarce resource. From mobile operator’s point of view, efficient utilization of the radio resources is needed while providing maximum coverage, and ensuring good quality of service with minimal infrastructure. In high capacity demanding areas, multilayer networks with multiband and multi radio access technologies are deployed, in order to meet the capacity requirements. In his doctoral thesis, Usman Sheikh has proposed a “Smart Traffic Handling” strategy, which is based on user’s required service type and location. Smart traffic handling scheme efficiently utilizes the different layers of the network, balances the load among them, and improves the system capacity. Power resources at base station are also limited. Usman Sheikh’s proposed “Power Control Scheme for High Speed Downlink Packet Access (HSDPA) network” improves the cell edge user experience, while maintaining the fairness among the other users in a cell. With the help of a proposed power control scheme, a user far from the base station can also enjoy the better quality of service. Generally, mobile operators use macro cells with wide beam antennas for wider coverage in the cell, but future capacity demands cannot be achieved by using only them. “Higher Order Sectorization” is one possible way to increase the system capacity. Usman Sheikh proposed new network layouts called “Snowflake” and “Flower” tessellations, for 6-sector and 12-sector sites, respectively. These tessellations can be used as a basis for making a nominal network plan for sites with higher order sectorization. These tessellations would be helpful for simulation purposes. Through his work, he has also tried to highlight the importance of deploying “Adaptive MIMO Switching” in Long Term Evolution (LTE) system, the fourth generation of wireless networks. In future, the fifth generation of wireless networks is expected to offer thousand times more capacity compared to LTE. The novel concept of “Single Path Multiple Access (SPMA)” given by Usman Sheikh is a revolutionary idea, and gives a possibility to increase the system capacity by a giant margin. SPMA can be considered as a right step towards 5G technology. Usman Sheikh’s work is of high importance not only from mobile operator’s point of view; rather his contributions to the scientific community will also lead to better user (customer) experience. His work will definitely benefit the mankind in utilizing the limited resources in an optimum and efficient way

    Islamic Culture and Western Civilization: The Prospects of Coexistence in the Thought of Alija Izetbegović

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    Alija Ali Izetbegović (1925-2003) is one of the outstanding Muslim thinkers in recent history who have re-conceptualized the Islamic worldview and ethos in the context of the contemporary world on the one hand and critically reflected upon the modern Western civilization, on the other. Izetbegović conceives Islam as a system representing a middle path between Christian spiritualism and materialism of modern civilization. However, like any profound philosophical system, his thought requires exposition and interpretation, which the present paper ventures to undertake. Specifically, the paper inquires whether and how far his vision of Islam facilitates coexistence between Muslims and the others, especially regarding the Muslims living in Western societies. The query is crucial because some writers have accused Izetbegović of being a fundamentalist who pursued an agenda of monolithic Islamic culture with little room for meaningful participation of non-Muslims. The paper concludes that contrary to such negative renderings of his thought, Izetbegović was a thinker with a vast intellectual spectrum and an open outlook. Some of his peculiar notions can be conducive to the coexistence between Muslims and other European communities as well as Islamic culture and Western civilization

    FPGA-based real-time moving target detection system for unmanned aerial vehicle application

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    Moving target detection is the most common task for Unmanned Aerial Vehicle (UAV) to find and track object of interest from a bird's eye view in mobile aerial surveillance for civilian applications such as search and rescue operation. The complex detection algorithm can be implemented in a real-time embedded system using Field Programmable Gate Array (FPGA). This paper presents the development of real-time moving target detection System-on-Chip (SoC) using FPGA for deployment on a UAV. The detection algorithm utilizes area-based image registration technique which includes motion estimation and object segmentation processes. The moving target detection system has been prototyped on a low-cost Terasic DE2-115 board mounted with TRDB-D5M camera. The system consists of Nios II processor and stream-oriented dedicated hardware accelerators running at 100 MHz clock rate, achieving 30-frame per second processing speed for 640 Ă— 480 pixels' resolution greyscale videos

    Capacity Limitation of Small Cell Densification

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    Deployment of small cells is considered as an easy approach for adding capacity to the system. However, it is important to realize that in a non-noise limited system, each additional cell increases the interference in the system. The target of this paper is to show the capacity limitation of the cellular network with an increasing number of small cells in a network. Ultra-dense deployment of small cells implies a high probability of line of sight (LOS) transmission between the transmitter (TX) and receiver (RX). The LOS transmission helps in enhancing the received signal strength, whereas, on the other hand, the interference power significantly grows with small cell densification. This paper presents the analytical analysis of bad cell border area for one-, and two-dimensional grid of small cells. The lamp post solution for the small cell deployment along the street is studied through simulations. The acquired results show that the overall interference in the system and the bad signal to interference plus noise ratio (SINR) cell border area grows with cell densification. System capacity saturates and then starts to collapse as the capacity loss due to the additional cell interference becomes dominant over the gain of cell densification after the saturation point.acceptedVersionPeer reviewe

    Inhibition of Hepatitis C Virus 3a genotype entry through Glanthus Nivalis Agglutinin

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    <p>Abstract</p> <p>Background</p> <p>Hepatitis C Virus (HCV) has two envelop proteins E1 and E2 which is highly glycosylated and play an important role in cell entry. Inhibition of virus at entry step is an important target to find antiviral drugs against HCV. Glanthus Nivalis Agglutinin (GNA) is a mannose binding lectin which has tendency for specific recognition and reversible binding to the sugar moieties of a wide variety of glycoproteins of enveloped viruses.</p> <p>Results</p> <p>In the present study, HCV pseudoparticles (HCVpp) for genotype 3a were produced to investigate the ability of GNA to block the HCV entry. The results demonstrated that GNA inhibit the infectivity of HCVpp and HCV infected serum in a dose-dependent manner and resulted in 50% reduction of virus at 1 ± 2 μg concentration. Molecular docking of GNA and HCV glycoproteins (E1 and E2) showed that GNA inhibit HCV entry by binding N-linked glycans.</p> <p>Conclusion</p> <p>These results demonstrated that targeting the HCV glycans is a new approach to develop antiviral drugs against HCV.</p

    Inhibition of full length Hepatitis C Virus particles of 1a genotype through small interference RNA

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    <p>Abstract</p> <p>Background</p> <p>Hepatitis C virus (HCV), a member of the <it>Flaviviridae </it>family of viruses, is a major cause of chronic hepatitis, liver cirrhosis and hepatocellular carcinoma. Currently, the only treatment available consists of a combination of Pegylated interferon alpha (INF-α) and ribavirin, but only half of the patients treated show a sufficient antiviral response. Thus there is a great need for the development of new treatments for HCV infections. RNA interference (RNAi) represents a new promising approach to develop effective antiviral drugs and has been extremely effective against HCV infection.</p> <p>Results</p> <p>This study was design to assess or explore the silencing effect of small interference RNAs (siRNAs) against full length HCV particles of genotype 1a. In the present study six 21-bp siRNAs were designed against different regions of HCV structural genes (Core, E1 and E2). Selected siRNAs were labeled as Csi 301, Csi 29, E1si 52, E1si 192, E2si 86 and E2si 493. Our results demonstrated that siRNAs directed against HCV core gene showed 70% reduction in viral titer in HCV infected liver cells. Moreover, siRNAs against E1 and E2 envelop genes showed a dramatic reduction in HCV viral RNA, E2si 86 exhibited 93% inhibition, while E1si 192, E2si 493 and E1si 52 showed 87%, 80%, and 66% inhibition respectively. No significant inhibition was detected in cells transfected with the negative control siRNA.</p> <p>Conclusion</p> <p>Our results suggested that siRNAs targeted against HCV structural genes efficiently silence full length HCV particles and provide an effective therapeutic option against HCV infection.</p

    Direct Path Interference Suppression Requirements for Bistatic Backscatter Communication System

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    The ambient backscatter communication (AmBC) system utilizes the existing ambient RF signals present in the atmosphere for backscattering the signal. One of the challenges for AmBC system is the interference at the receiver module caused by the direct path signal from the ambient source. The purpose of this paper is to study the coverage aspects of the bi-static backscatter communication system in a typical urban environment at sub-1GHz frequencies using simulations in MATLAB. For the simulation, 3rd generation partnership project (3GPP) urban microcellular and international telecommunication union (ITU) device-to-device (D2D) propagation models are used. Moreover, the dynamic range i.e., the difference in the received power level of the direct path and the backscatter path is investigated. For correctly decoding the backscatter signal at the reader, the target value set for the dynamic range is less than 30 dB. This paper studies the importance of direct path interference suppression for the successful deployment of a bi-static backscatter communication system.acceptedVersionPeer reviewe

    Interference Analysis of Bi-static Backscatter Communication System: Two Backscatter Devices

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    Ambient backscatter communication (AmBC) systems utilize existing ambient radio frequency (RF) signals to establish an indirect communication link between a transmitter (TX) and a receiver (RX). Backscatter devices (BDs) modulate their useful information on the incoming ambient signal emitted by the TX, as such their range is usually a very short event when only one BD is considered. This paper aims to analyze the impact of the interference generated due to the presence of another BD in a bi-static backscatter communication system. It is observed from the simulation results that the received signal degradation is mostly due to the cross interference of the other BD, which can be mitigated using successive interference cancellation (SIC) techniques. The level of both cross interference and self interference is significant when the interfering BD is located close to the target BD or the receiver. Therefore, AmBC systems can support more than one BD in an environment as long as the BDs are placed more than a wavelength apart from each other and RX.acceptedVersionPeer reviewe
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