83 research outputs found

    5G uplink interference simulations, analysis and solutions: The case of pico cells dense deployment

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    The launch of the new mobile network technology has paved the way for advanced and more productive industrial applications based on high-speed and low latency services offered by 5G. One of the key success points of the 5G network is the available diversity of cell deployment modes and the flexibility in radio resources allocation based on user’s needs. The concept of Pico cells will become the future of 5G as they increase the capacity and improve the network coverage at a low deployment cost. In addition, the short-range wireless transmission of this type of cells uses little energy and will allow dense applications for the internet of things. In this contribution, we present the advantages of using Pico cells and the characteristics of this type of cells in 5G networks. Then, we will do a simulation study of the interferences impact in uplink transmission in the case of PICO cells densified deployment. Finally, we will propose a solution for interference avoidance between pico cells that also allows flexible management of bands allocated to the users in uplink according to user’s density and bandwidth demand

    A New Downlink Scheduling Algorithm Proposed for Real Time Traffic in LTE System

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    The Third Generation Partnership Project (3GPP) has developed a new cellular standard based packet switching allowing high data rate, 100 Mbps in Downlink and 50 Mbps in Uplink, and having the flexibility to be used in different bandwidths ranging from 1.4 MHz up to 20 MHz, this standard is termed LTE (Long Term Evolution). Radio Resource Management (RRM) procedure is one of the key design roles for improving LTE system performance, Packet scheduling is one of the RRM mechanisms and it is responsible for radio resources allocation, However, Scheduling algorithms are not defined in 3GPP specifications. Therefore, it gets a track interests for researchers. In this paper we proposed a new LTE scheduling algorithm and we compared its performances with other well known algorithms such as Proportional Fairness (PF), Modified Largest Weighted Delay First (MLWDF), and Exponential Proportional Fairness (EXPPF) in downlink direction. The simulation results shows that the proposed scheduler satisfies the quality of service (QoS) requirements of the real-time traffic in terms of packet loss ratio (PLR), average throughput and packet delay. This paper also discusses the key issues of scheduling algorithms to be considered in future traffic requirements

    Approximated fixed points via completion

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    In this paper, using the concept of completion, we establish the existence of approximate fixed points for contracting set-valued mappings defined in a metric space not necessarily assumed to be complete. As a consequence, we obtain approximate versions of the famous results of the global Contraction Mapping Principle and Nadler Fixed Point Theorem without completeness

    Exponential MLWDF (EXP-MLWDF) Downlink Scheduling Algorithm Evaluated in LTE for High Mobility and Dense Area Scenario

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    Nowadays, with the advent of smartphones, most of people started to make voice and video conference calls continuously even in a high mobility scenario, the bandwidth requirements have increased considerably, which can cause network congestion phenomena. To avoid network congestion problems and to support high mobility scenario, 3GPP has developed a new cellular standard based packet switching, termed LTE (Long Term Evolution). The purpose of this paper is to evaluate the performance of the new proposed algorithm, named Exponential Modified Largest Weighted Delay First ‘EXP-MLWDF’, for high mobility scenario and with the presence of a large number of active users, in comparison with the well-known algorithms such as a proportional fair algorithm (PF), Exponential Proportional Fairness (EXP/PF), Logarithm Rule (LOG-Rule), Exponential Rule (EXP-Rule) and Modified Largest Weighted Delay First (MLWDF). The performance evaluation is conducted in terms of system throughput, delay and PLR. Finally, it will be concluded that the proposed scheduler satisfies the quality of service (QoS) requirements of the real-time traffic in terms of packet loss ratio (PLR), average throughput and packet delay. Because of the traffic evolution, some key issues related to scheduling strategies that will be considered in the future requirements are discussed in this article

    Use of Lactococci isolated from Moroccan traditional dairy product: Development of a new starter culture

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    Ninety (90) strains were isolated from Moroccan traditional dairy product and identified using biochemical and molecular tests. Among the 20 identified lactic acid cocci, two strains were selected for their important acidifying activity: Lactococcus lactis subsp. lactis (AML8) and Lactococcus lactis subsp. cremoris (BML2). Both revealed remarkable acidifying activity, especially when they were mixed in cultures, even in greater values than in the traditional Lben (a Moroccan dairy product). Sensory analysis showed that the so fermented milk has been more appreciated than the Lben. These results show the potential of the two strains as possible culture starter for fermented dairy product.Keywords: Lactococci, acidifying activity, fermented milk, Lben.African Journal of Biotechnology Vol. 12(38), pp. 5662-566

    Proportional fair buffer scheduling algorithm for 5G enhanced mobile broadband

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    The impending next generation of mobile communications denoted 5G intends to interconnect user equipment, things, vehicles, and cities. It will provide an order of magnitude improvement in performance and network efficiency, and different combinations of use cases enhanced mobile broadband (eMBB), ultra reliable low latency communications (URLLC), massive internet of things (mIoT) with new capabilities and diverse requirements. Adoption of advanced radio resource management procedures such as packet scheduling algorithms is necessary to distribute radio resources among different users efficiently. The proportional fair (PF) scheduling algorithm and its modified versions have proved to be the commonly used scheduling algorithms for their ability to provide a tradeoff between throughput and fairness. In this article, the buffer status is combined with the PF metric to suggest a new scheduling algorithm for efficient support for eMBB. The effectiveness of the proposed scheduling strategy is proved through à comprehensive experimental analysis based on the evaluation of different quality of service key performance indicators (QoS KPIs) such as throughput, fairness, and buffer status

    Etude et conception d’un quadrupleur de fréquence en technologie MMIC pour des applications à 60 GHz

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    Dans ce papier, un circuit multiplicateur de fréquence par 4 est proposé. Ce quadrupleur fonctionne dans la bande millimétrique [56-64 GHz], il est conçu en technologie MMIC (Monolithic Microwave Integrated Circuit) en utilisant le procédé technologique PH15 de la fonderie UMS. Le circuit quadrupleur de fréquence sera utilisé pour générer des fréquences porteuses appartenant à la bande [56-64 GHZ] permettant de réaliser la démodulation du signal RF d’une liaison de communication sans fil en bande millimétrique. Ce quadrupleur fera partie du bloc récepteur d’une liaison de communication sans fil à très haut débit en bande millimétrique à 60 GHz

    Automatic target detection and localization using ultra-wideband radar

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    The pulse ultra-wide band (UWB) radar consists of switching of energy of very short duration in an ultra-broadband emission chain, and the UWB signal emitted is an ultrashort pulse, of the order of nanoseconds, without a carrier. These systems can indicate the presence and distances of a distant object, call a target, and determine its size, shape, speed, and trajectory. In this paper, we present a UWB radar system allowing the detection of the presence of a target and its localization in a road environment based on the principle of correlation of the reflected signal with the reference and the determination of its correlation peak

    A CMOS 0.35 μm High Quality Factor Active Filter

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    In this work we describe the topology of an active filter using active inductor principle with a high quality factor in CMOS technology. This filter shows a resonant frequency at 6.4 GHz. A negative resistor circuit and Q-enhancement techniques such as channel width and current and voltage optimisation of the transistors compensated serial and parallel loss. S21 parameters were studied in two frequencies 6 GHz and 12 GHz according to the value of a capacitance that tunes the frequency of the filter
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