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Добірка наукової літератури з теми "MULTIPLEXING EFFICIENCY"

Автор: Grafiati

Опубліковано: 11 вересня 2023

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Статті в журналах з теми "MULTIPLEXING EFFICIENCY"

Sun, Xueping, Rui Ma, Xinxin Pu, Shaobo Ge, Jin Cheng, Xiangyang Li, Quan Wang, Shun Zhou, and Weiguo Liu. "High-Efficiency Polarization Multiplexing Metalenses." Nanomaterials 12, no. 9 (April 28, 2022): 1500. http://dx.doi.org/10.3390/nano12091500.

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The polarization multiplexing technique is a well-established method that improves the communication capacity of an optical system. In this paper, we designed orthogonal linear and circular polarization multiplexing metalens using a library of rectangle TiO2 nanostructures. The former can independently focus x- and y-linearly polarized incident lights to designed positions with a focusing efficiency of 53.81% and 51.56%, respectively, whereas the latter with two preset focal points can independently control left and right circularly polarized incident lights with a focusing efficiency of 42.45% and 42.46%, respectively. We also show that both metalenses can produce diffraction-limited focal spots for four polarization states with no obvious distortion, which opens up new applications in polarization imaging and polarization detection.

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Tian, Ruiyuan, Buon Kiong Lau, and Zhinong Ying. "Multiplexing Efficiency of MIMO Antennas." IEEE Antennas and Wireless Propagation Letters 10 (2011): 183–86. http://dx.doi.org/10.1109/lawp.2011.2125773.

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Alasti, H. "Spectral efficiency enhancement of multiresolution multiplexing." Electronics Letters 53, no. 18 (August 2017): 1254–56. http://dx.doi.org/10.1049/el.2017.2343.

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Zhao, Yuntao, Bo Bo, and Yongxin Feng. "A Scheduling Method of Cross-Layers Optimization of Polling Weight for AOS Multiplexing." International Journal of Digital Multimedia Broadcasting 2019 (March 24, 2019): 1–10. http://dx.doi.org/10.1155/2019/2560623.

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The core mechanism of Advanced Orbit System (AOS) mainly contains the packet channel multiplexing and the virtual channel multiplexing. The multiplexing efficiency and frame time directly affect the performance of the AOS and even the whole system. In this paper, in order to optimize AOS multiplexing performance, a scheduling method of cross-layers optimization of polling weight (CLOPW) is proposed. Different from single sublayer optimization such as the isochronous frame methods, the novel method focuses on factors related to AOS performance of two core sublayers, such as packet distribution, residual function, cache capacity, frame time, and multiplexing efficiency. We build a multiple factors framing model of finite buffer and deduce the formula of packet multiplexing efficiency based on the short correlation. Furthermore, we give the formula for the virtual channel utilization and delay of cross-layer optimization. The experimental results show that the novel scheduling method of cross-layers optimization of polling weight is higher utilization of virtual channel and lower average delay than the isochronous frame method.

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Chen, Xiaoming. "Throughput Multiplexing Efficiency for MIMO Antenna Characterization." IEEE Antennas and Wireless Propagation Letters 12 (2013): 1208–11. http://dx.doi.org/10.1109/lawp.2013.2282952.

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Bi, Ming Xue. "A Novel Packet Channel Multiplexing Control Algorithms of AOS." Advanced Materials Research 838-841 (November 2013): 3247–50. http://dx.doi.org/10.4028/www.scientific.net/amr.838-841.3247.

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The tradition packet channel multiplexing control algorithm of Advanced Orbiting Systems has the obvious disadvantages such as high time delay, high packet loss probability and low system throughput. Those depress the capability of the space communications badly. Based on the packet parameters, a new packet channel multiplexing control algorithm is proposed to optimize the tradition fixed multiplexing time. Under the prerequisite to ensure the maximal multiplexing efficiency, the processing time of packet channel multiplexing is limited, the packet loss probability is depressed, and the multiplexing throughput is advanced effectively.

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Zhao, Yuntao, and Lishi Liu. "A Scheduling Model of Isochronous Frame Generation on Self-similar Traffic of AOS Multiplexing." International Journal of Online Engineering (iJOE) 14, no. 07 (July 27, 2018): 15. http://dx.doi.org/10.3991/ijoe.v14i07.8203.

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As the first layer of AOS multiplexing, the frame scheduling performance has a great effect on the efficiency of multiplexing. Traditional researches about the scheduling model mainly focus on the source packet arrival model of Poisson process. In this paper, an ON/OFF source arrival model and Pareto distribution of AOS multiplexing in self-similar service traffic is used to establish a isochronous frame-generated method through rigorous theoretical analysis, which results in a calculable formula of average packet delay and MPDU average multiplex efficiency. According to simulation of MATLAB, the simulation curve coincides with that of theory. The novel model contributes to the improvement of average packet delay and MPDU average multiplex efficiency on AOS.

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Wang, Hua Hua, Wang Qiang Zheng, and Nan Lv. "A Method to Improve PDCCH Blind Detection Efficiency Used in TD-LTE System." Advanced Materials Research 926-930 (May 2014): 3585–89. http://dx.doi.org/10.4028/www.scientific.net/amr.926-930.3585.

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In order to improve the efficiency of blind detection in receiving end, this paper deeply considered structure of the PDCCH multiplexing data and analyze the current algorithm. A more efficient algorithm based on preprocessing the PDCCH multiplexing data in certain search space is proposed in this paper. This algorithm ably reduces the blind detection times.

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Schmid, Matthew J., Kalpana Manthiram, Scott M. Grayson, James C. Willson, Jason E. Meiring, Kathryn M. Bell, Andrew D. Ellington, and C. Grant Willson. "Feature Multiplexing—Improving the Efficiency of Microarray Devices." Angewandte Chemie 118, no. 20 (May 12, 2006): 3416–19. http://dx.doi.org/10.1002/ange.200502151.

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Schmid, Matthew J., Kalpana Manthiram, Scott M. Grayson, James C. Willson, Jason E. Meiring, Kathryn M. Bell, Andrew D. Ellington, and C. Grant Willson. "Feature Multiplexing—Improving the Efficiency of Microarray Devices." Angewandte Chemie International Edition 45, no. 20 (May 12, 2006): 3338–41. http://dx.doi.org/10.1002/anie.200502151.

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Дисертації з теми "MULTIPLEXING EFFICIENCY"

ZHOU, BIN. "IMPROVING ROUTING EFFICIENCY, FAIRNESS, DIFFERENTIATED SERVISES AND THROUGHPUT IN OPTICAL NETWORKS." Doctoral diss., University of Central Florida, 2006. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3261.

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Wavelength division multiplexed (WDM) optical networks are rapidly becoming the technology of choice in next-generation Internet architectures. This dissertation addresses the important issues of improving four aspects of optical networks, namely, routing efficiency, fairness, differentiated quality of service (QoS) and throughput. A new approach for implementing efficient routing and wavelength assignment in WDM networks is proposed and evaluated. In this approach, the state of a multiple-fiber link is represented by a compact bitmap computed as the logical union of the bitmaps of the free wavelengths in the fibers of this link. A modified Dijkstra's shortest path algorithm and a wavelength assignment algorithm are developed using fast logical operations on the bitmap representation. In optical burst switched (OBS) networks, the burst dropping probability increases as the number of hops in the lightpath of the burst increases. Two schemes are proposed and evaluated to alleviate this unfairness. The two schemes have simple logic, and alleviate the beat-down unfairness problem without negatively impacting the overall throughput of the system. Two similar schemes to provide differentiated services in OBS networks are introduced. A new scheme to improve the fairness of OBS networks based on burst preemption is presented. The scheme uses carefully designed constraints to avoid excessive wasted channel reservations, reduce cascaded useless preemptions, and maintain healthy throughput levels. A new scheme to improve the throughput of OBS networks based on burst preemption is presented. An analytical model is developed to compute the throughput of the network for the special case when the network has a ring topology and the preemption weight is based solely on burst size. The analytical model is quite accurate and gives results close to those obtained by simulation. Finally, a preemption-based scheme for the concurrent improvement of throughput and burst fairness in OBS networks is proposed and evaluated. The scheme uses a preemption weight consisting of two terms: the first term is a function of the size of the burst and the second term is the product of the hop count times the length of the lightpath of the burst.
Ph.D.
School of Computer Science
Engineering and Computer Science
Computer Science

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Liu, Qijia. "Power efficiency and diversity issues for peak power constrained wireless communications." Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/34829.

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Along with the rapidly increasing demand for high data rate communications, orthogonal frequency division multiplexing (OFDM) has become a popular modulation in current and future communication standards. By distributing a high-speed data stream to many parallel low-rate data streams, OFDM is able to mitigate the detrimental effects of multipath fading using simple one-tap equalizers and achieve high spectral efficiency. However, the OFDM signal waveform suffers from large envelop variations, which are usually measured by the peak-to-average power ratio (PAR). In wireless transmitters, many RF components, especially the power amplifiers, are inherently nonlinear and peak power constrained. Therefore, low power efficiency and/or severe nonlinear distortions are the main shortcomings of OFDM systems. In this dissertation, we develop algorithms and analyze performance bounds for peak power constrained wireless communications. To address the balance between power efficiency and nonlinear distortions, we model the peak power constrained OFDM systems in both statistical and deterministic manners. We first propose an error vector magnitude (EVM) optimization algorithm to strictly satisfy the distortion requirements in accordance with communication standards and provide the maximum power efficiency for OFDM transmitters without receiver-side cooperations. Moreover, we develop a multi-channel partial transmit sequence (MCPTS) PAR reduction method for OFDM-based frequency-division multiple access (OFDM-FDMA) multiuser systems, which can achieve significant power efficiency improvement without using side information. Joint MCPTS and power allocation schemes are also proposed to improve the error performance of OFDM-FDMA systems. Furthermore, diversity-enabled communication systems have practical merits in combating channel fadings. Therefore, in the second part of this dissertation, peak power constrained diversity techniques are proposed. The error performance of peak power constrained single-input multiple-output (SIMO) OFDM is studied. Several low-complexity SIMO-OFDM transceiver designs are presented to collect full antenna diversity with respective performance and complexity tradeoffs. The next major piece of work in this dissertation addresses the design of peak power constrained amplify-and-forward (AF) cooperative networks, which enable the cooperative diversity with single-antenna terminals. The effects of the availability of channel state information and the peak power constraint on the diversity performance are theoretically studied. Design criteria for general diversity-enabled AF relaying strategies are established and further applied to the designs in peak power constrained networks. In the end, a general theorem that relates the diversity gain function with the probability density function of instantaneous signal-to-noise ratio is derived and used to analyze the diversity performance of relay selection schemes.

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Qian, Hua. "Power Efficiency Improvements for Wireless Transmissions." Diss., Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/11649.

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Many communications signal formats are not power efficient because of their large peak-to-average power ratios (PARs). Moreover, in the presence of nonlinear devices such as power amplifiers (PAs) or mixers, the non-constant-modulus signals may generate both in-band distortion and out-of-band interference. Backing off the signal to the linear region of the device further reduces the system power efficiency. To improve the power efficiency of the communication system, one can pursue two approaches: i) linearize the PA; ii) reduce the high PAR of the input signal. In this dissertation, we first explore the optimal nonlinearity under the peak power constraint. We show that the optimal nonlinearity is a soft limiter with a specific gain calculated based on the peak power limit, noise variance, and the probability density function of the input amplitude. The result is also extended to the fading channel case. Next, we focus on digital baseband predistortion linearization for power amplifiers with memory effects. We build a high-speed wireless test-bed and carry out digital baseband predistortion linearization experiments. To implement adaptive PA linearization in wireless handsets, we propose an adaptive digital predistortion linearization architecture that utilizes existing components of the wireless transceiver to fulfill the adaptive predistorter training functionality. We then investigate the topic of PAR reduction for OFDM signals and forward link CDMA signals. To reduce the PAR of the OFDM signal, we propose a dynamic selected mapping (DSLM) algorithm with a two-buffer structure to reduce the computational requirement of the SLM method without sacrificing the PAR reduction capability. To reduce the PAR of the forward link CDMA signal, we propose a new PAR reduction algorithm by introducing a relative offset between the in-phase branch and the quadrature branch of the transmission system.

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Chen, Xin. "Energy efficient wired networking." Thesis, Queen Mary, University of London, 2015. http://qmro.qmul.ac.uk/xmlui/handle/123456789/7966.

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This research proposes a new dynamic energy management framework for a backbone Internet Protocol over Dense Wavelength Division Multiplexing (IP over DWDM) network. Maintaining the logical IP-layer topology is a key constraint of our architecture whilst saving energy by infrastructure sleeping and virtual router migration. The traffic demand in a Tier 2/3 network typically has a regular diurnal pattern based on people‟s activities, which is high in working hours and much lighter during hours associated with sleep. When the traffic demand is light, virtual router instances can be consolidated to a smaller set of physical platforms and the unneeded physical platforms can be put to sleep to save energy. As the traffic demand increases the sleeping physical platforms can be re-awoken in order to host virtual router instances and so maintain quality of service. Since the IP-layer topology remains unchanged throughout virtual router migration in our framework, there is no network disruption or discontinuities when the physical platforms enter or leave hibernation. However, this migration places extra demands on the optical layer as additional connections are needed to preserve the logical IP-layer topology whilst forwarding traffic to the new virtual router location. Consequently, dynamic optical connection management is needed for the new framework. Two important issues are considered in the framework, i.e. when to trigger the virtual router migration and where to move virtual router instances to? For the first issue, a reactive mechanism is used to trigger the virtual router migration by monitoring the network state. Then, a new evolutionary-based algorithm called VRM_MOEA is proposed for solving the destination physical platform selection problem, which chooses the appropriate location of virtual router instances as traffic demand varies. A novel hybrid simulation platform is developed to measure the performance of new framework, which is able to capture the functionality of the optical layer, the IP layer data-path and the IP/optical control plane. Simulation results show that the performance of network energy saving depends on many factors, such as network topology, quiet and busy thresholds, and traffic load; however, savings of around 30% are possible with typical medium-sized network topologies.

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Dudal, Clément. "Forme d'onde multiporteuse pour de la diffusion par satellite haute capacité." Phd thesis, Toulouse, INPT, 2012. http://oatao.univ-toulouse.fr/8342/1/dudal.pdf.

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Cette thèse se concentre sur l’amélioration conjointe de l'efficacité spectrale et de l'efficacité en puissance de schémas de transmission par satellite. L’émergence de nouveaux services et l'augmentation du nombre d’acteurs dans le domaine nécessitent de disposer de débits de plus en plus importants avec des ressources de plus en plus limitées. Les progrès réalisés ces dernières années sur la technologie embarquée et dans le domaine des communications numériques permettent de considérer des schémas de transmission à plus haute efficacité spectrale et en puissance. Cependant, l’enjeu majeur des schémas de transmission proposes actuellement reste de rentabiliser les ressources disponibles. L’étude développée dans cette thèse explore les possibilités d’amélioration conjointe de l’efficacité spectrale et de l’efficacité en puissance en proposant la combinaison de la modulation Cyclic Code-Shift-Keying (CCSK), dont l’efficacité en puissance augmente avec l’élévation du degré de la modulation, avec une technique de multiplexage par codage de type Code-Division Multiplexing (CDM) pour pallier la dégradation de l’efficacité spectrale liée à l’étalement du spectre induit par la modulation CCSK. Deux approches basées sur l’utilisation de séquences de Gold de longueur N sont définies: Une approche multi-flux avec un décodeur sphérique optimal en réception. La complexité liée à l’optimalité du décodeur conduit à des valeurs d'efficacité spectrale limitées mais l’étude analytique des performances, vérifiée par des simulations, montre une augmentation de l'efficacité en puissance avec l'efficacité spectrale. Une approche mono-flux justifiée par l’apparition de redondance dans les motifs résultant du multiplexage des séquences. L’approche mono-flux propose des valeurs d’efficacité spectrale équivalente aux schémas retenus dans le standard DVB-S2 avec une amélioration de l’efficacité en puissance à partir d’un certain seuil de rapport signal à bruit par rapport à ces schémas. Par la suite, l'étude porte sur la transposition de plusieurs symboles de modulation sur les porteuses d’un système OFDM et sur les bénéfices et avantages d’une telle approche. Elle se conclut sur l’apport d’un codage canal basé sur des codes par bloc non binaires Reed-Solomon et LDPC. La forme d’onde proposée offre des points de fonctionnement à haute efficacité spectrale et haute efficacité en puissance avec des perspectives intéressantes. Dans le contexte actuel, son application reste limitée par ses fluctuations d’amplitude mais est envisageable dans un contexte de transmission multiporteuse, comme attendu dans les années à venir.

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García, Elvira David. "Contributions on DC microgrid supervision and control strategies for efficiency optimization through battery modeling, management, and balancing techniques." Doctoral thesis, Universitat Rovira i Virgili, 2021. http://hdl.handle.net/10803/672010.

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Aquesta tesi presenta equips, models i estratègies de control que han estat desenvolupats amb l'objectiu final de millorar el funcionament d'una microxarxa CC. Es proposen dues estratègies de control per a millorar l'eficiència dels convertidors CC-CC que interconnecten les unitats de potència de la microxarxa amb el bus CC. La primera estratègia, Control d'Optimització de Tensió de Bus centralitzat, administra la potència del Sistema d'Emmagatzematge d'Energia en Bateries de la microxarxa per aconseguir que la tensió del bus segueixi la referència dinàmica de tensió òptima que minimitza les pèrdues dels convertidors. La segona, Optimització en Temps Real de la Freqüència de Commutació, consisteix a operar localment cada convertidor a la seva freqüència de commutació òptima, minimitzant les seves pèrdues. A més, es proposa una nova topologia d'equilibrador actiu de bateries mitjançant un únic convertidor CC-CC i s'ha dissenyat la seva estratègia de control. El convertidor CC-CC transfereix càrrega cel·la a cel·la, emprant encaminament de potència a través d'un sistema d'interruptors controlats. L'estratègia de control de l'equalitzador aconsegueix un ràpid equilibrat del SOC evitant sobrecompensar el desequilibri. Finalment, es proposa un model simple de degradació d'una cel·la NMC amb elèctrode negatiu de grafit. El model combina la simplicitat d'un model de circuit equivalent, que explica la dinàmica ràpida de la cel·la, amb un model físic del creixement de la capa Interfase Sòlid-Electròlit (SEI), que prediu la pèrdua de capacitat i l'augment de la resistència interna a llarg termini. El model proposat quantifica la incorporació de liti al rang de liti ciclable necessària per a aconseguir els límits de OCV després de la pèrdua de liti ciclable en la reacció secundària. El model de degradació SEI pot emprar-se per a realitzar un control predictiu de bateries orientat a estendre la seva vida útil.
Aquesta tesi presenta equips, models i estratègies de control que han estat desenvolupats amb l'objectiu final de millorar el funcionament d'una microxarxa CC. Es proposen dues estratègies de control per a millorar l'eficiència dels convertidors CC-CC que interconnecten les unitats de potència de la microxarxa amb el bus CC. La primera estratègia, Control d'Optimització de Tensió de Bus centralitzat, administra la potència del Sistema d'Emmagatzematge d'Energia en Bateries de la microxarxa per aconseguir que la tensió del bus segueixi la referència dinàmica de tensió òptima que minimitza les pèrdues dels convertidors. La segona, Optimització en Temps Real de la Freqüència de Commutació, consisteix a operar localment cada convertidor a la seva freqüència de commutació òptima, minimitzant les seves pèrdues. A més, es proposa una nova topologia d'equilibrador actiu de bateries mitjançant un únic convertidor CC-CC i s'ha dissenyat la seva estratègia de control. El convertidor CC-CC transfereix càrrega cel·la a cel·la, emprant encaminament de potència a través d'un sistema d'interruptors controlats. L'estratègia de control de l'equalitzador aconsegueix un ràpid equilibrat del SOC evitant sobrecompensar el desequilibri. Finalment, es proposa un model simple de degradació d'una cel·la NMC amb elèctrode negatiu de grafit. El model combina la simplicitat d'un model de circuit equivalent, que explica la dinàmica ràpida de la cel·la, amb un model físic del creixement de la capa Interfase Sòlid-Electròlit (SEI), que prediu la pèrdua de capacitat i l'augment de la resistència interna a llarg termini. El model proposat quantifica la incorporació de liti al rang de liti ciclable necessària per a aconseguir els límits de OCV després de la pèrdua de liti ciclable en la reacció secundària. El model de degradació SEI pot emprar-se per a realitzar un control predictiu de bateries orientat a estendre la seva vida útil.
This dissertation presents a set of equipment, models and control strategies, that have been developed with the final goal of improving the operation of a DC microgrid. Two control strategies are proposed to improve the efficiency of the DC-DC converters that interface the microgrid’s power units with the DC bus. The first strategy is centralized Bus Voltage Optimization Control, which manages the power of the microgrid’s Battery Energy Storage System to make the bus voltage follow the optimum voltage dynamic reference that minimizes the converters’ losses. The second control strategy is Online Optimization of Switching Frequency, which consists in locally operating each converter at its optimum switching frequency, again minimizing power losses. The two proposed optimization strategies have been validated in simulations. Moreover, a new converter-based active balancing topology has been proposed and its control strategy has been designed. This equalizer topology consists of a single DC-DC converter that performs cell-to-cell charge transfer employing power routing via controlled switches. The control strategy of the equalizer has been designed to achieve rapid SOC balancing while avoiding imbalance overcompensation. Its performance has been validated in simulation. Finally, a simple degradation model of an NMC battery cell with graphite negative electrode is proposed. The model combines the simplicity of an equivalent circuit model, which explains the fast dynamics of the cell, with a physical model of the Solid-Electrolyte Interphase (SEI) layer growth process, which predicts the capacity loss and the internal resistance rise in the long term. The proposed model fine-tunes the capacity loss prediction by accounting for the incorporation of unused lithium reserves of both electrodes into the cyclable lithium range to reach the OCV limits after the side reaction has consumed cyclable lithium. The SEI degradation model can be used to perform predictive control of batteries oriented toward extending their lifetime.

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Hussaini, Abubakar S. "Energy efficient radio frequency system design for mobile WiMax applications. Modelling, optimisation and measurement of radio frequency power amplifier covering WiMax bandwidth based on the combination of class AB, class B, and C operations." Thesis, University of Bradford, 2012. http://hdl.handle.net/10454/5749.

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In today´s digital world, information and communication technology accounts for 3% and 2% of the global power consumption and CO2 emissions respectively. This alarming figure is on an upward trend, as future telecommunications systems and handsets will become even more power hungry since new services with higher bandwidth requirements emerge as part of the so called ¿future internet¿ paradigm. In addition, the mobile handset industry is tightly coupled to the consumer need for more sophisticated handsets with greater battery lifetime. If we cannot make any significant step to reducing the energy gap between the power hungry requirements of future handsets, and what battery technology can deliver, then market penetration for 4G handsets can be at risk. Therefore, energy conservation must be a design objective at the forefront of any system design from the network layer, to the physical and the microelectronic counterparts. In fact, the energy distribution of a handset device is dominated by the energy consumption of the RF hardware, and in particular the power amplifier design. Power amplifier design is a traditional topic that addresses the design challenge of how to obtain a trade-off between linearity and efficiency in order to avoid the introduction of signal distortion, whilst making best use of the available power resources for amplification. However, the present work goes beyond this by investigating a new line of amplifiers that address the green initiatives, namely green power amplifiers. This research work explores how to use the Doherty technique to promote efficiency enhancement and thus energy saving. Five different topologies of RF power amplifiers have been designed with custom-made signal splitters. The design core of the Doherty technique is based on the combination of a class B, class AB and a class C power amplifier working in synergy; which includes 90-degree 2-way power splitter at the input, quarter wavelength transformer at the output, and a new output power combiner. The frequency range for the amplifiers was designed to operate in the 3.4 - 3.6 GHz frequency band of Europe mobile WiMAX. The experimental results show that 30dBm output power can be achieved with 67% power added efficiency (PAE) for the user terminal, and 45dBm with 66% power added efficiency (PAE) for base stations which marks a 14% and 11% respective improvement over current stateof- the-art, while meeting the power output requirements for mobile WiMAX applications.

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Shahpari, Ali. "Next generation optical access networks : technologies and economics." Doctoral thesis, Universidade de Aveiro, 2015. http://hdl.handle.net/10773/14857.

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Анотація:

Doutoramento em Engenharia Eletrotécnica - Telecomunicações
The work presented herein, studies Next Generation Optical Access Networks (NG-OAN) economically (e.g. energy consumption) and technologically (e.g. rate, reach and dedicated/shared bandwidth). The work is divided into four main topics: energy efficiency in optical access architectures, novel spectrally efficient Long-Reach Passive Optical Networks (LR-PON), crosstalk impacts in heterogeneous and homogenous access networks and hybrid optical wireless transmissions. We investigate the impact of user profiles, optical distribution network topologies and equipment characteristics on resource sharing and power consumption in LR-PON. To have a clear vision on the energy consumption evolution of each part of NG-OAN, a model is proposed to evaluate the energy efficiency of optical access technologies. A spectrally efficient bidirectional Ultra-Dense Wavelength Division Multiplexing (UDWDM) PON architecture is developed using Nyquist shaped 16-ary quadrature amplitude modulation, offering up to 10 Gb/s service capabilities per user or wavelength. Performance of this system in terms of receiver sensitivity and nonlinear tolerance under different network transmission capacity conditions are experimentally optimized. In bi-directional transmis-sion, using frequency up/down-shifting of Nyquist pulse shaped signal from optical carrier, a full bandwidth allocation and easy maintenance of UDWDM networks as well as reduction of Rayleigh back-scattering are achieved. Moreover, self-homodyne detection is used to relax the laser linewidth requirement and digital signal processing complexity at the optical network unit. Simplified numerical model to estimate the impact of Raman crosstalk of multi-system next generation PONs in video overlay is proposed. Coexistence of considered G.98X ITU-T series and coherent multi-wavelength systems is considered and assessed. Additionally, the performances of bidirectional hybrid optical wireless coherent PONs over different optical distribution network power budgets and hybrid splitting ratios are evaluated.
O trabalho aqui apresentado estuda redes óticas de acesso de próxima geração (NG-OAN) nas vertentes económica (consumo de energia) e tecnológica (taxa, alcance e largura de banda dedicada/partilhada). O trabalho está dividido em quatro grandes temas de investigação: a eficiência energética em arquiteturas de acesso ótico, as redes óticas passivas de longo alcance (LR-PON) com nova eficiência espetral, o impacto da diafonia em redes de acesso heterogéneas e homogéneas e as transmissões ópticas híbridas com tecnologias sem fio. Investiga-se o impacto dos perfis dos utilizadores, as tipologias da rede de distribuição ótica, as características do equipamento de partilha de recursos e o consumo de energia em LR-PON. Para se ter uma visão clara sobre o consumo de energia de cada parte das NG-OAN, é proposto um modelo para avaliar a eficiência energética das tecnologias de acesso óticas. Desenvolve-se uma arquitetura PON bi-direcional com elevada eficiência espetral, recorrendo a multiplexagem por divisão de comprimento de onda ultra-densa (UDWDM), modulação de amplitude em quadratura com formato de impulso de Nyquist, oferecendo até 10 Gb/s por utilizador/comprimento de onda. O desempenho deste sistema em termos de sensibilidade do recetor e da tolerância à resposta não linear do canal de comunicação, sob diferentes condições de transmissão, é avaliado experimentalm-ente. Em transmissão bi-direcional, utilizando desvio de frequência (cima/baixo) do impulso com formato de Nyquist relativo à portadora ótica conseguiu-se uma alocação de largura de banda completa e uma manutenção mais simplificada de redes UDWDM, bem como a redução do espalhamento de Rayleigh. Além disso, a deteção auto-homodina é usada para relaxar o requisito de largura de linha do laser e a complexidade do processamento digital de sinal nas unidades da rede ótica. Propõe-se um modelo numérico simplificado para estimar o impacto da diafonia de Raman em sistemas PON de próxima geração, com sobreposição do sinal de vídeo. É analisada a coexistência da série G.98X ITU-T e são considerados e avaliados sistemas coerentes multi-comprimento de onda. Adicionalmente avaliam-se os desempenhos de PONs bi-direcionais híbridas, considerando tecnologia coerente e propagação por espaço livre, para diferentes balanços de potência e taxas de repartição na rede ótica de distribuição.

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Hussaini, Abubakar Sadiq. "Energy efficient radio frequency system design for mobile WiMax applications : modelling, optimisation and measurement of radio frequency power amplifier covering WiMax bandwidth based on the combination of class AB, class B, and C operations." Thesis, University of Bradford, 2012. http://hdl.handle.net/10454/5749.

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In today's digital world, information and communication technology accounts for 3% and 2% of the global power consumption and CO2 emissions respectively. This alarming figure is on an upward trend, as future telecommunications systems and handsets will become even more power hungry since new services with higher bandwidth requirements emerge as part of the so called 'future internet' paradigm. In addition, the mobile handset industry is tightly coupled to the consumer need for more sophisticated handsets with greater battery lifetime. If we cannot make any significant step to reducing the energy gap between the power hungry requirements of future handsets, and what battery technology can deliver, then market penetration for 4G handsets can be at risk. Therefore, energy conservation must be a design objective at the forefront of any system design from the network layer, to the physical and the microelectronic counterparts. In fact, the energy distribution of a handset device is dominated by the energy consumption of the RF hardware, and in particular the power amplifier design. Power amplifier design is a traditional topic that addresses the design challenge of how to obtain a trade-off between linearity and efficiency in order to avoid the introduction of signal distortion, whilst making best use of the available power resources for amplification. However, the present work goes beyond this by investigating a new line of amplifiers that address the green initiatives, namely green power amplifiers. This research work explores how to use the Doherty technique to promote efficiency enhancement and thus energy saving. Five different topologies of RF power amplifiers have been designed with custom-made signal splitters. The design core of the Doherty technique is based on the combination of a class B, class AB and a class C power amplifier working in synergy; which includes 90-degree 2-way power splitter at the input, quarter wavelength transformer at the output, and a new output power combiner. The frequency range for the amplifiers was designed to operate in the 3.4 - 3.6 GHz frequency band of Europe mobile WiMAX. The experimental results show that 30dBm output power can be achieved with 67% power added efficiency (PAE) for the user terminal, and 45dBm with 66% power added efficiency (PAE) for base stations which marks a 14% and 11% respective improvement over current stateof- the-art, while meeting the power output requirements for mobile WiMAX applications.

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Zhu, Jiannan. "Novel energy-efficient DWDM systems for low-cost optical communication applications." Thesis, University of Cambridge, 2015. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.709467.

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Книги з теми "MULTIPLEXING EFFICIENCY"

Taberlet, Pierre, Aurélie Bonin, Lucie Zinger, and Eric Coissac. DNA amplification and multiplexing. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198767220.003.0006.

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After a brief reminder of the principles underlying the polymerase chain reaction (PCR), Chapter 6 “DNA amplification and multiplexing” discusses the choice of a DNA polymerase for the PCR. In particular, it warns against the use of proofreading polymerases, that can lead to a substantial loss of PCR specificity. Chapter 6 insists on the benefits of including different types of controls in the PCR (e.g., PCR negatives and positives, tagging system controls, etc.). The most common causes of PCR failures and their solutions are addressed, as well as the precautions to take to avoid and monitor contaminations. Chapter 6 also deals with the particular case of blocking oligonucleotides, which aim at reducing the amplification of undesired sequences. It gives some valuable guidelines to design such oligonucleotides and use them efficiently. Finally, Chapter 6 presents different strategies for tagging individual samples during the amplification, to allow subsequent multiplexing during the sequencing step.

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Seņkāns, Uģis. Development and Evaluation of Hybrid FBG Sensors and WDM-PON Fiber Optical Systems. RTU Press, 2021. http://dx.doi.org/10.7250/9789934227004.

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With the development of fiber optical data transmission technologies and infrastructure on a global scale, the use of fiber optical sensors to perform sensing functions is becoming increasingly important mainly due to their advantages, such as small size, light weight, multiplexing capabilities and others. Therefore, in order to ensure more efficient use of optical sensor technologies, it is necessary to research and search for new solutions for the integration and use of fiber optical sensors in existing and future fiber optical communication system architecture. The main goal of the Doctoral Thesis is to study and evaluate the interaction of FBG fiber optical sensor networks and WDM-PON metro-access transmission systems implemented in a single system with theoretical and experimental research. In order to evaluate their performance in a unified system, a detailed study of the interaction between the FBG optical sensor network and the fiber optic data transmission system has been performed by implementing mathematical modeling and experimental development of such systems.

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Частини книг з теми "MULTIPLEXING EFFICIENCY"

Li, An, Di Che, Qian Hu, Xi Chen, and William Shieh. "Spectrally Efficient Multiplexing - OFDM." In Enabling Technologies for High Spectral-Efficiency Coherent Optical Communication Networks, 157–200. Hoboken, NJ, USA: John Wiley & Sons, Inc, 2016. http://dx.doi.org/10.1002/9781119078289.ch5.

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Bosco, Gabriella. "Spectrally Efficient Multiplexing: NYQUIST-WDM." In Enabling Technologies for High Spectral-Efficiency Coherent Optical Communication Networks, 123–56. Hoboken, NJ, USA: John Wiley & Sons, Inc, 2016. http://dx.doi.org/10.1002/9781119078289.ch4.

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Ryf, Roland, and Nicolas K. Fontaine. "Space-Division Multiplexing and MIMO Processing." In Enabling Technologies for High Spectral-Efficiency Coherent Optical Communication Networks, 547–608. Hoboken, NJ, USA: John Wiley & Sons, Inc, 2016. http://dx.doi.org/10.1002/9781119078289.ch16.

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Iizuka, Yasuki, and Kayo Iizuka. "Exceeding the Efficiency of Distributed Approximate Algorithms Enabling by the Multiplexing Method." In Knowledge-Based and Intelligent Information and Engineering Systems, 366–77. Berlin, Heidelberg: Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-23854-3_39.

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Mutenhabundo, Winnie, Tawanda Mushiri, Timothy Gutu, and Patson Zvandasara. "Liquid Desiccant Dehumidification Systems: Jet Cross-Talking Effect in Multi-electrosprays." In Lecture Notes in Mechanical Engineering, 258–65. Cham: Springer International Publishing, 2023. http://dx.doi.org/10.1007/978-3-031-28839-5_29.

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AbstractWhen liquid desiccant systems are employed to dehumidify air electrospraying technique helps to increase the surface area of the liquid. Multiplexing of the jets by introducing several emitters for increased efficiency is commendable but, there is a tendency of the jets to cross talk with each other due to electrical shielding. Cross talking of jets will result in the failure of the jets to break properly into droplets for effective dehumidification. This piece of work analyzed the conditions for electrical shielding among jets which results in efficient electrospray. To evaluate how cross talking affects multiple emitter nozzles, the mathematical model was built by superimposing the electric potentials of one emitter in an array of emitters. A Computational Fluid Dynamics simulation model was developed to investigate the conditions for electrical shielding among jets during electrospray process with glycerol as the working substance. In flow modelling, Ansys Fluent with Volume of Fluid and the Taylor Dielectric model were involved. The flow rate that guarantees stability in the electrospray was determined together with the optimum voltage resulting in a spray current which reduces electrical shielding. An analysis on the electrical conductivity of the liquid to ensure stability and efficiency in electrospray was done. The pressure contours of the nozzle were determined together with velocity of the desiccant against density. Emitter spacing, applied voltage, flow rate and the electrical conductivity plays a pivotal role on the prevention of cross talking of jets during the electrospraying process.

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Zhang, Xiuyan, and Guobin Tao. "The Research of Adaptive Modulation Technology in OFDM System." In Proceeding of 2021 International Conference on Wireless Communications, Networking and Applications, 739–48. Singapore: Springer Nature Singapore, 2022. http://dx.doi.org/10.1007/978-981-19-2456-9_74.

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AbstractOrthogonal frequency division multiplexing (OFDM) as a special multi-carrier transmission technology has good resistance to narrow-band interference and frequency selective fading ability. Compared with traditional modulation techniques, adaptive modulation can enhance bandwidth efficiency and system capacity. Therefore, applying adaptive modulation in OFDM systems can take full advantage of spectrum resources, and it is suitable for the high-speed and reliable mobile communication systems in the future. The purpose of this paper is to improve traditional OFDM adaptive algorithms (Hughes-Hartogs, Chow) to realize bits allocation, power allocation better. In this paper, simulation results demonstrated that the improved Levin-Campello algorithm lowers algorithm’s complexity greatly and owns better flexibility, at the same time, it guarantees good the bit error rate (BER) performance and can be applied to speech communication (fixed rate) and data communication (variable rate) in wireless communication systems.

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Darwazeh, Izzat, Ryan C. Grammenos, and Tongyang Xu. "Spectrally Efficient Frequency Division Multiplexing for 5G." In 5G Mobile Communications, 261–97. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-34208-5_10.

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Yang, Yi, and Huiyang Zhou. "A Highly Efficient FFT Using Shared-Memory Multiplexing." In Numerical Computations with GPUs, 363–77. Cham: Springer International Publishing, 2014. http://dx.doi.org/10.1007/978-3-319-06548-9_17.

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Paturzo, M., P. Memmolo, A. Tulino, A. Finizio, L. Miccio, and P. Ferraro. "Numerical multiplexing and de-multiplexing techniques for efficient storage and transmission of digital holographic information." In Fringe 2009, 1–4. Berlin, Heidelberg: Springer Berlin Heidelberg, 2009. http://dx.doi.org/10.1007/978-3-642-03051-2_32.

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Fu, Haohuan, Xiaowen Li, Ji Shen, and Weijia Jia. "Efficient Multiplexing Protocol for Low Bit Rate Multi-point Video Conferencing." In Lecture Notes in Computer Science, 478–87. Berlin, Heidelberg: Springer Berlin Heidelberg, 2005. http://dx.doi.org/10.1007/11599463_47.

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Тези доповідей конференцій з теми "MULTIPLEXING EFFICIENCY"

Chen, Xiaoming, Jiazhi Tang, Shitao Zhu, and Anxue Zhang. "Characterizations of MIMO Antennas Using Multiplexing Efficiency." In 2018 IEEE International Symposium on Antennas and Propagation & USNC/URSI National Radio Science Meeting. IEEE, 2018. http://dx.doi.org/10.1109/apusncursinrsm.2018.8608470.

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Tian, Ruiyuan, Buon Kiong Lau, and Zhinong Ying. "Multiplexing efficiency of MIMO antennas with user effects." In 2012 IEEE Antennas and Propagation Society International Symposium and USNC/URSI National Radio Science Meeting. IEEE, 2012. http://dx.doi.org/10.1109/aps.2012.6348701.

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An, Haiyan, John Jiang, Roff Robert, Stephan Strohmaier, and Georg Treusch. "Bar efficiency and beam quality for coarse wavelength multiplexing." In 2012 IEEE Photonics Society Summer Topical Meeting Series. IEEE, 2012. http://dx.doi.org/10.1109/phosst.2012.6280731.

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Khider, Ibrahim, Salah Elfaki, Laila Ibrahim, and Albedeir Yaseen. "The high efficiency of slotted optical time division multiplexing." In 2011 International Conference on Electrical and Control Engineering (ICECE). IEEE, 2011. http://dx.doi.org/10.1109/iceceng.2011.6057740.

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Tian, Ruiyuan, Buon Kiong Lau, and Zhinong Ying. "Multiplexing efficiency of MIMO antennas in arbitrary propagation scenarios." In 2012 6th European Conference on Antennas and Propagation (EuCAP). IEEE, 2012. http://dx.doi.org/10.1109/eucap.2012.6205897.

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Ahmad, N. A. A., M. N. Junita, S. A. Aljunid, and C. B. M. Rashidi. "Spectral efficiency improvement using subcarrier multiplexing in OCDMA system." In 2016 3rd International Conference on Electronic Design (ICED). IEEE, 2016. http://dx.doi.org/10.1109/iced.2016.7804627.

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Yan, Aiqin, Shiquan Tao, Dayong Wang, Mengquan Shi, and Feipeng Wu. "Multiplexing holograms in the photopolymer with equal diffraction efficiency." In Photonics Asia 2004, edited by Duanyi Xu, Kees A. Schouhamer Immink, and Keiji Shono. SPIE, 2005. http://dx.doi.org/10.1117/12.576964.

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Chen, Pengcheng, and Yong Zhang. "Manipulating nonlinear Ewald sphere for holography multiplexing." In Digital Holography and Three-Dimensional Imaging. Washington, D.C.: Optica Publishing Group, 2022. http://dx.doi.org/10.1364/dh.2022.w5a.7.

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We propose the quasi-phase-matching-division multiplexing holography by manipulating nonlinear Ewald sphere. The scheme is capable to enhance the conversion efficiency compared with the traditional scheme and allows high-capacity multi-channel nonlinear multiplexing holography.

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Ma, Junjie, Zheng Yao, and Mingquan Lu. "Analytic Efficiency Optimal Constant-Envelope Multiplexing Technique for GNSS Signals." In 30th International Technical Meeting of The Satellite Division of the Institute of Navigation (ION GNSS+ 2017). Institute of Navigation, 2017. http://dx.doi.org/10.33012/2017.15376.

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Raymer, Michael G., and Dileep V. Reddy. "High-Efficiency Multiplexing of Quantum Information in Optical Temporal Modes." In Frontiers in Optics. Washington, D.C.: OSA, 2018. http://dx.doi.org/10.1364/fio.2018.fw6d.3.

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