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This dissertation presents a contribution to helicopter axial piston pump monitoring through modelling and simulation. A lumped-parameter model of such pump is developed to serve as a virtual test bench for monitoring studies. As lumped-parameter models of axial piston pumps are less detailed than distributed-parameter models, the author proposes improvements of lumped-parameter modelling state-of-the-art, focusing on the monitoring industrial need. The proposal concentrates on the pressure compensator simulation in degraded conditions, and on the slipper/swashplate leakage computation through a variable gap height. The developed pump model is compared to experimental data. Then, a graphical tool is proposed, (the Damage Identification Curve, DIC), which allows for the isolation of pump degradation within the hydraulic system using discharge and case drain pressure steady-state measurements. The study is concluded by recommendations for increasing the maturity level of the proposed monitoring approach.; Cette thèse présente une contribution à la surveillance des pompes à pistons axiaux des hélicoptères par modélisation et simulation. Un modèle de pompe à paramètres localisés est développé pour servir de banc d'essai pour les études de surveillance. L'auteur propose des améliorations de l'état de l'art de la modélisation à paramètres localisés des pompes à pistons axiaux, en se concentrant sur le besoin industriel de surveillance. La proposition se concentre sur la simulation du régulateur de pression dans des conditions dégradées, et sur le calcul des fuites de patin/plateau à travers un jeu de hauteur variable. Le modèle de pompe développé est comparé à des données expérimentales. Un outil graphique (la Courbe d'Identification des Dommages, DIC) est ensuite proposé. Cet outil permet d'isoler la dégradation de la pompe dans le système hydraulique à l'aide de mesures en régime permanent de la pression de refoulement et de la pression de drain. L'étude se termine par des recommandations pour augmenter le niveau de maturité technologique de l'approche proposée.

This dissertation presents a contribution to helicopter axial piston pump monitoring through modelling and simulation. A lumped-parameter model of such pump is developed to serve as a virtual test bench for monitoring studies. As lumped-parameter models of axial piston pumps are less detailed than distributed-parameter models, the author proposes improvements of lumped-parameter modelling state-of-the-art, focusing on the monitoring industrial need. The proposal concentrates on the pressure compensator simulation in degraded conditions, and on the slipper/swashplate leakage computation through a variable gap height. The developed pump model is compared to experimental data. Then, a graphical tool is proposed, (the Damage Identification Curve, DIC), which allows for the isolation of pump degradation within the hydraulic system using discharge and case drain pressure steady-state measurements. The study is concluded by recommendations for increasing the maturity level of the proposed monitoring approach.; Cette thèse présente une contribution à la surveillance des pompes à pistons axiaux des hélicoptères par modélisation et simulation. Un modèle de pompe à paramètres localisés est développé pour servir de banc d'essai pour les études de surveillance. L'auteur propose des améliorations de l'état de l'art de la modélisation à paramètres localisés des pompes à pistons axiaux, en se concentrant sur le besoin industriel de surveillance. La proposition se concentre sur la simulation du régulateur de pression dans des conditions dégradées, et sur le calcul des fuites de patin/plateau à travers un jeu de hauteur variable. Le modèle de pompe développé est comparé à des données expérimentales. Un outil graphique (la Courbe d'Identification des Dommages, DIC) est ensuite proposé. Cet outil permet d'isoler la dégradation de la pompe dans le système hydraulique à l'aide de mesures en régime permanent de la pression de refoulement et de la pression de drain. L'étude se termine par des recommandations pour augmenter le niveau de maturité technologique de l'approche proposée.

This study investigates the feasibility of using Long Term Evolution (LTE) cellular networks for the real-time smart grid state estimation. The smart grid state estimation requires measurement reports from different nodes installed in the smart grid. Therefore, the uplink LTE radio delay performance is selected as key performance indicator for the collection of the desired measurements. The analysis is conducted for two types of measurement nodes, namely Smart Meters (SMs) and Wide Area Monitoring and Supervision (WAMS) nodes, installed in the (future) smart grids. The SM and WAMS measurements are fundamental input for the real-time state estimation of the smart grid. The LTE delay evaluation approach is performed via ‘snap-shot’ system level simulations of an LTE system where the physical resource allocation, modulation and coding scheme selection and retransmissions are modelled. The impact on the LTE delay is analyzed for two different LTE resource allocation approaches, namely, simple random scheduler with fixed LTE physical resource allocation per user, and time-based LTE scheduler with flexible LTE physical resource allocation per user. The results show that time-delay prioritized scheduling in combination with flexible PRB assignment greatly reduces the maximum delay when compared to simple random scheduling and fixed PRB assignment. This type of scheduling approach and flexible PRB allocation is recommended for supporting time critical smart grid applications within LTE.

5th generation radio networks should efficiently support services with diverse requirements. For achieving better resource utilization, the sharing of the radio channel between the different services is an attractive solution. While the downlink multiplexing can be well accomplished with dynamic scheduling, efficient multiplexing of enhanced mobile broadband (eMBB) and ultra-reliable low-latency communications (URLLC) in uplink is still an open problem. In particular, we consider the case of URLLC using grant-free allocation for sporadic transmissions, multiplexed on shared resources with eMBB with high data volume. Since the moment in which a grant-free transmission occurs is not known, URLLC and eMBB transmissions overlay. Power control settings are then assessed as a way to manage the performance trade-off between the services. Due to the complexity of 5G new radio, the evaluation is based on advanced system level simulations. Insights regarding the configuration of fractional power control settings upon the coexistence of the different services are presented.

This study investigates the feasibility of using Long Term Evolution (LTE) cellular networks for the real-time smart grid state estimation. The smart grid state estimation requires measurement reports from different nodes installed in the smart grid. Therefore, the uplink LTE radio delay performance is selected as key performance indicator for the collection of the desired measurements. The analysis is conducted for two types of measurement nodes, namely Smart Meters (SMs) and Wide Area Monitoring and Supervision (WAMS) nodes, installed in the (future) smart grids. The SM and WAMS measurements are fundamental input for the real-time state estimation of the smart grid. The LTE delay evaluation approach is performed via ‘snap-shot’ system level simulations of an LTE system where the physical resource allocation, modulation and coding scheme selection and retransmissions are modelled. The impact on the LTE delay is analyzed for two different LTE resource allocation approaches, namely, simple random scheduler with fixed LTE physical resource allocation per user, and time-based LTE scheduler with flexible LTE physical resource allocation per user. The results show that time-delay prioritized scheduling in combination with flexible PRB assignment greatly reduces the maximum delay when compared to simple random scheduling and fixed PRB assignment. This type of scheduling approach and flexible PRB allocation is recommended for supporting time critical smart grid applications within LTE.

This thesis concentrates on evaluating and improving the throughput performances of mobile users in high speed vehicles. In particular, high speed train (HST) scenarios are considered. Emphasis is placed on practical designs and methods that take into account distinctive HST characteristics. A two-hop communication link, i.e., base station (BS)-to-HST and HST-to-onboard users (OBUs) is adopted. The main target is to improve the throughput performance on the BS-to-HST communication link, which is assumed to be the main bottleneck in the whole communication link, since the HST-to-OBU communication link is assumed to have good channel quality due to the short link distance with relatively stationary OBUs. The algorithms developed are assessed through link and system level simulations. A theoretical and practical study of the throughput maximization problem in a single and multi-cell multiple-input multiple-output orthogonal frequency-division multiplexing (MIMO-OFDM) train scenario are considered with and without cooperation between train carriages. Two low-complexity transmission schemes based on simple antenna selection (AS) methods with spatial multiplexing (SM) are proposed. The simulation results demonstrate that large antenna arrays with AS and SM transmission strategies have the potential to significantly improve the throughput of the BS-to-train link in HST scenarios. Resource sharing methodologies between the moving relay nodes (MRNs) on the HST and ground macro users (GMUs) were also studied in a multi-cell MIMO-OFDM train scenario. Direct application of existing resource scheduling methods will not be appropriate to efficiently and fairly share resources, since the MRNs and the GMUs have different processing capabilities. Hence, two hybrid resource scheduling methods are analyzed in conjunction with joint and disjoint resource management. The tradeoff between the number of MRNs and receive antennas that should be installed on an HST was also examined in the context of throughput performance and capital expenditure. Results show that joint scheduling does not provide the best overall performance and there is a need to schedule each group of mobile terminals (MTs) separately. Finally, the feasibility of the use of higher frequency bands (HFBs) was examined in HST scenarios. A timer-based beam selection scheme for HST, which does not require any training time to select the appropriate beam is also proposed. The proposed beam selection scheme (PBSS) displays a close performance to the ideal singular value decomposition (SVD) scheme. Tiivistelmä Tämä väitöskirja keskittyy mobiilikäyttäjien tiedonsiirtonopeuksien arviointiin ja parantamiseen nopeasti liikkuvissa kulkuneuvoissa. Työ käsittelee erityisesti tiedonsiirtoa suurnopeusjunissa. Työssä korostetaan käytännön menetelmiä, jotka ottavat huomioon nopeasti liikkuvien junien tiedonsiirron erityispiirteet. Työssä käytetään kahden hypyn linkkimallia, jossa tiedonsiirto kulkee tukiasemalta junaan ja junasta käyttäjälle, joka on junassa. Päätavoite on parantaa datanopeuksia tukiaseman ja junan välisessä tiedonsiirtolinkissä, jonka uskotaan olevan suurin pullonkaula koko tiedonsiirtolinkissä, koska junan ja lähes paikallaan olevan käyttäjän välinen kanava voidaan olettaa hyvälaatuiseksi linkin lyhyyden vuoksi. Kehitettyjen algoritmien suorituskykyä arvioidaan linkki- ja järjestelmätason simulaatioilla. Työssä tutkitaan tiedonsiirtonopeuden maksimointiongelmaa teoreettisella ja käytännön tasolla yhden ja usean solun MIMO OFDM junaskenaarioissa, joissa junan vaunut tekevät tai eivät tee yhteistyötä. Työssä esitetään kaksi alhaisen kompleksisuuden lähetysmenetelmää, jotka hyödyntävät yksinkertaista antennin valintamenetelmää ja tilatason multipleksointia. Simulointitulokset osoittavat, että suuret antenniryhmät, jotka hyödyntävät näitä lähetysmenetelmiä, voivat parantaa merkittävästi tiedonsiirtonopeutta tukiasemalta junaan päin. Työssä tutkitaan myös resurssien jakomenetelmiä liikkuvien junassa olevien releiden ja maatason makrokäyttäjien välillä monen solun MIMO-OFDM junaskenaariossa. Nykyisten resurssinhallintamenetelmien käyttö ei ole suoraan mahdollista tehokasta ja oikeudenmukaista resurssien jakoa, koska releillä ja makrokäyttäjillä on erilaiset prosessointikyvyt. Tämän vuoksi työssä analysoidaan kahta hybridimenetelmään resurssien skeduloinnille. Tutkimukset selventävät tasapainoa releiden lukumäärän ja junaan asennettavien vastaanotinantennien välillä tiedonsiirtonopeuden ja kustannusten osalta. Tulokset osoittavat, että yhteinen resurssien jako ei saavuta parasta suorituskykyä, eikä ole tarvetta ajoittaa jokaista matkaviestinterminaaliryhmää erikseen. Lopuksi työssä tutkitaan korkeampien taajuusalueiden soveltuvuutta tiedonsiirtoon suurnopeusjunissa. Työssä ehdotetaan ajastinpohjaista keilanvalintamenetelmää, joka ei vaadi opetusjaksoa sopivan keilan valintaan. Ehdotetun menetelmän saavuttama suorituskyky on lähellä ideaalisen singulaariarvohajotelmaa hyödyntävän menetelmän suorituskykyä.

Ultra-reliable and low latency communication (URLLC) presents the most challenging use cases for fifth generation (5G) mobile networks. Traditionally the focus for mobile broadband has been to optimize the system throughput for high speed data traffic. However the optimization criteria for URLLC should focus on achieving small packets transmissions under strict targets such as 99.999% reliability within 1 ms. Power control is one candidate technology component for improving reliability and latency. In this work we investigate the power control for grant-free URLLC transmissions through extensive system level simulations in a urban outdoor scenario. We initially compare different settings for open loop power control (OLPC) with full and with fractional path loss compensation. Then we evaluate whether power boosting the retransmission can reduce the probability of packets delays under the 1 ms constraint. We also discuss the practical implication of applying power boosting. With full path loss compensation and boosting retransmissions, we show that a URLLC load such as 1200 small packets per second per cell can be achieved in the considered scenario.

In this paper, we assess the suitability of NB-IoT (Narrowband Internet of Things) cellular technology for smart grid applications, concentrating on the reliable and timely delivery of Outage Restoration & Management (ORM) messages at the event of a local or regional power outage. Using system-level simulations modelling of both the cellular NB-IoT and the energy distribution networks for different environments, we present an extensive sensitivity analysis of the ORM service performance w.r.t. various radio network configurations. In particular, we propose and analyze different packet schedulers, an essential mechanism in optimizing the service performance. A key outcome of the study is the conclusion that indeed NB-IoT is a suitable technology for supporting ORM services in smart grids, accompanied with a proposed near-optimal radio network configuration to best do so.

In this paper, we assess the suitability of NB-IoT (Narrowband Internet of Things) cellular technology for smart grid applications, concentrating on the reliable and timely delivery of Outage Restoration Management (ORM) messages at the event of a local or regional power outage. Using system-level simulations modelling of both the cellular NB-IoT and the energy distribution networks for different environments, we present an extensive sensitivity analysis of the ORM service performance w.r.t. various radio network configurations. In particular, we propose and analyze different packet schedulers, an essential mechanism in optimizing the service performance. A key outcome of the study is the conclusion that indeed NB-IoT is a suitable technology for supporting ORM services in smart grids, accompanied with a proposed near-optimal radio network configuration to best do so.

The aim of this thesis is to devise novel co-primary spectrum sharing (CoPSS) methods for future fifth generation (5G) networks and beyond. The target is to improve data rates of small cell networks (SCNs) in which mobile network operators (MNOs) share their dedicated frequency spectrum (spectrum pooling) or a common spectrum (mutual renting). The performance of the proposed methods is assessed through extensive system-level simulations. MNOs typically acquire exclusive usage rights for certain frequency bands and have little incentive to share spectrums with other operators. However, due to higher cost and spectrum scarcity at lower frequencies it is expected that efficient use of the spectrum in 5G networks will rely more on spectrum sharing than exclusive licenses. This is especially true for new higher candidate frequencies (> 6 GHz) that do not have a pre-existing spectrum regulation framework. In the first part of the thesis, we tackle the challenge of providing higher data rates within limited spectral resources. Each SCN MNO has its own dedicated spectrum, and each MNO defines a percentage of how much its spectrum it is willing to share. The idea of the proposed CoPSS algorithms is that the spectrum is dynamically shared among MNOs based on their spectrum utilization, which is shared among MNOs in the network. This way interference can be avoided and spectrum utilization is maximized. Unused resources are shared equally between overloaded MNOs for a given time instant. Thus, only short-term fairness among overloaded SCNs can be guaranteed. In the second part, we consider a multi-operator small cell network where MNOs share a common pool of radio resources. The goal is to ensure the long term fairness of spectrum sharing without coordination among small cell base stations. We develop a decentralized control mechanism for base stations using the Gibbs sampling based learning tool, which allocates suitable amount of the spectrum for each base station while avoiding interference from SCNs and maximizing the total network throughput. In the studied scenarios, we show the importance of coordination among MNOs when the dedicated spectrum is shared. However, when MNOs share a common spectrum, a decentralized control mechanism can be used to allocate suitable amounts of spectrum for each base station. The proposed algorithms are shown to be effective for different network layouts, by achieving significant data rate enhancements with a low overhead. Tiivistelmä Tämä väitöskirja keskittyy kehittämään uusia menetelmiä, joilla jaetaan taajuuksia useiden operaattoreiden kesken tulevista viidennen sukupolven verkoista alkaen. Päätavoite on parantaa tiedonsiirtonopeuksia sellaisissa piensoluverkoissa, joissa matkapuhelinoperaattorit jakavat joko heidän omia taajuusalueitaan tai heillä yhteisomistuksessa olevia taajuuksia. Kehitettyjen menetelmien suorituskykyä arvioidaan mittavien järjestelmätason simulointien avulla. Matkapuhelinoperaattorit tyypillisesti omistavat yksin tietyt taajuusalueet, eivätkä ole valmiita jakamaan niitä. On kuitenkin oletettu, että tulevaisuudessa matkapuhelinoperaattorit joutuvat jakamaan taajuuksia, koska taajuusalueet ovat kalliita ja niukkoja erityisesti matalilla taajuusalueilla. Korkeammat taajuusalueet (> 6 GHz) puolestaan muodostavat otollisen alustan tehokkaalle spektrin jaetulle käytölle, koska niillä ei ole vielä olemassa olevaa taajuussääntelyä. Väitöskirjan ensimmäisessä osassa keskitytään kasvattamaan tiedonsiirtonopeuksia kun jokainen matkapuhelinoperaattori omistaa oman taajuuskaistansa ja matkapuhelinoperaattorit määrittävät kuinka suuren prosentuaalisen osuuden ovat valmiita jakamaan. Esitettyjen algoritmien päätavoite on jakaa taajuuksia dynaamisesti matkapuhelinoperaattoreiden kesken. Algoritmeissa hyödynnetään tietoa matkapuhelinoperaattoreiden taajuuden käyttöasteesta, jonka matkapuhelinoperaattoritkommunikoivat toisilleen. Näin häiriö voidaan välttää ja taajuuden käyttö maksimoidaan. Käyttämättömät taajuudet jaetaan tasaisesti matkapuhelinoperaattorien kesken tietyllä ajanhetkellä. Näin voidaan taata lyhytaikainen oikeudenmukainen taajuuksien käyttö, mutta ei pitkäaikaista oikeudenmukaista taajuuksien käyttöä. Väitöskirjan toisessa osassa matkapuhelinoperaattorit jakavat yhteisomistuksessa olevia taajuuksia. Tavoitteena on saavuttaa pitkäaikainen taajuuksien oikeudenmukainen käyttö, kun piensoluverkot eivät kommunikoi keskenään. Työssä kehitetään piensoluverkoille hajautettu algoritmi, joka perustuu oppimistyökaluun Gibbs-näytteistys. Näin saadaan allokoitua jokaiselle tukiasemalle tarvittava määrä taajuusresursseja niin, että häiriö tukiasemien välillä minimoidaan ja koko piensoluverkon suorituskyky maksimoidaan. Tutkituissa skenaarioissa osoitetaan matkapuhelinoperaattoreiden välisen koordinaation tärkeys, kun jaetaan omia taajuusalueita. Toisaalta kun operaattorit jakavat yhteisomistuksessa olevia taajuuksia on mahdollista käyttää algoritmeja, joissa ei ole koordinaatiota matkapuhelinoperaattoreiden kesken. Väitöskirjassa vahvistetaan kehitettyjen algoritmien olevan tehokkaita ja sopivan monenlaisiin verkkoympäristöihin saavuttaen merkittäviä parannuksia tiedonsiirtonopeuteen ilman suuria kustannuksia.

This study investigates the feasibility of using Long Term Evolution (LTE), for the real-time state estimation of the smart grids. This enables monitoring and control of future smart grids. The smart grid state estimation requires measurement reports from different nodes in the smart grid and therefore the uplink LTE radio delay performance is selected as key performance indicator. The analysis is conducted for two types of measurement nodes, namely smart meters (SMs) and wide area monitoring and supervision (WAMS) nodes, installed in the (future) smart grids. The SM and WAMS measurements are fundamental input for the real-time state estimation of the smart grid. The LTE delay evaluation approach is via ‘snap-shot’ system level simulations of an LTE system where the physical resource allocation, modulation and coding scheme selection and retransmissions are modelled. The impact on the LTE delay is analyzed for different granularities of LTE resource allocation, for both urban and suburban environments. The results show that the impact of LTE resource allocation granularity on delay performance is more visible at lower number of nodes per cell. Different environments (with different inter-site distances) have limited impact to the delay performance. In general, it is challenging to reach a target maximum delay of 1 s in realistic LTE deployments (This work is partly funded by the FP7 SUNSEED project, with EC grant agreement no: 619437.). © ICST Institute for Computer Sciences, Social Informatics and Telecommunications Engineering 2017.

This study investigates the feasibility of using Long Term Evolution (LTE), for the real-time state estimation of the smart grids. This enables monitoring and control of future smart grids. The smart grid state estimation requires measurement reports from different nodes in the smart grid and therefore the uplink LTE radio delay performance is selected as key performance indicator. The analysis is conducted for two types of measurement nodes, namely smart meters (SMs) and wide area monitoring and supervision (WAMS) nodes, installed in the (future) smart grids. The SM and WAMS measurements are fundamental input for the real-time state estimation of the smart grid. The LTE delay evaluation approach is via ‘snap-shot’ system level simulations of an LTE system where the physical resource allocation, modulation and coding scheme selection and retransmissions are modelled. The impact on the LTE delay is analyzed for different granularities of LTE resource allocation, for both urban and suburban environments. The results show that the impact of LTE resource allocation granularity on delay performance is more visible at lower number of nodes per cell. Different environments (with different inter-site distances) have limited impact to the delay performance. In general, it is challenging to reach a target maximum delay of 1 s in realistic LTE deployments (This work is partly funded by the FP7 SUNSEED project, with EC grant agreement no: 619437.). © ICST Institute for Computer Sciences, Social Informatics and Telecommunications Engineering 2017.

5th generation mobile networks will have to cope with a high degree of heterogeneity in terms of services, mobility, number of devices and so on. Thus, diverse and often contradicting key performance indicators need to be supported, but having multiple radio access technologies for multi-service support below 6GHz will be too costly. FANTASTIC-5G will develop a new multi-service air interface through a modular design. To allow the system to adapt to the anticipated heterogeneity, some properties need to be pursued, like simplicity, flexibility, scalability, versatility, efficiency and future proofness. Based on these properties, a selected set of use cases and link and network design will be presented. The paper will also comprise validation and system level simulations through some indicative results and will conclude with the overall impact to 5G standardisation. Copyright (c) 2016 John Wiley & Sons, Ltd.

International audience; The work is related to an Agile Filter which is a specific RF block to be inserted between an antenna and a first stage of pre-amplification in future on board antenna systems or any future multi-purpose communications terminals. It will be able to process signals in the frequency range between 2 and 18 GHz with target insertion loss below 3dB. The basic idea of the demonstrator studied and developed in this project is to evaluate a SiP approach combining heterogeneous technologies and 3D integration and packaging. This paper presents the process flow used to design, fabricate and integrate in 3D a tunable RF filter which tunability is obtained by the use of MEMS varactors based on a copper on glass technology and stacked on micro-PCD for the electronic control functions. MEMS+ parameterized structures for RF MEMS varactor designs are presented with dimension constraints to be compatible with the space available at the end of each combline sub-filter. Indeed, the MEMS capacitors are composed of a mobile square membrane of 210μm by side and overall size of 600μm. In addition, these RF MEMS tunable capacitor models were automatically transferred into VerilogA for rapid system-level simulation usable further in ADS environment to verify the RF performances.

In this paper we study the performance of an interference aware iterative block decision feedback equalizer (IBDFE) for the uplink of LTE-Advanced with single carrier (SC) transmissions. The receiver makes use of the correlation between the interference in the receiving antennas and minimizes the mean squared error (MMSE) of the detected symbols. Link level simulation results show that the proposed receiver clearly outperforms the conventional IBDFE and the linear interference rejection combining (IRC) detector. System level simulation results show that the use of the new iterative receiver achieves additional throughput gains. However, the gains obtained depend on the schedulers employed and on the number of receiving antennas. info:eu-repo/semantics/publishedVersion

Smart antennas exploit the inherent spatial diversity of the mobile radio channel, provide an antenna gain, and also enable spatial interference suppression leading to reduced intracell as well as intercell interference. Especially, for the downlink of future CDMA-based mobile communications systems, transmit beamforming is seen as a well-promising smart antenna technique. The main objective of this paper is to study the performance of diverse antenna array topologies when applied for transmit beamforming in the downlink of CDMA-based networks. In this paper, we focus on uniform linear array (ULA) and uniform circular array (UCA) topologies. For the ULA, we consider three-sector base stations with one linear array per sector. While recent research on downlink beamforming is often restricted to one single cell, this study takes into account the important impact of intercell interference on the performance by evaluating complete networks. Especially, from the operator perspective, system capacity and system coverage are very essential parameters of a cellular system so that there is a clear necessity of intensive system level investigations. Apart from delivering assessments on the performance of the diverse antenna array topologies, in the paper also different antenna array parameters, such as element spacing and beamwidth of the sector antennas, are optimized. Although we focus on the network level, fast channel fluctuations are taken into account by including them analytically into the signal-to-interference calculation.

Conference of 2014 IEEE International Symposium on Circuits and Systems, ISCAS 2014 ; Conference Date: 1 June 2014 Through 5 June 2014; Conference Code:107394; International audience; Spin-transfer torque magnetic memory (STT-MRAM) is currently under intense academic and industrial development, since it features nonvolatility, high write and read speed and high endurance. In this work, we show that when used in an original regime, it can additionally act as a stochastic memristive device, appropriate to implement a 'synaptic' function. We introduce basic concepts relating to STT-MRAM cell behavior and its possible use to implement learning-capable synapses. System-level simulations on a problem of car counting highlight the potential of the technology for learning systems. Monte Carlo simulations show its robustness to device variations. These results open the way for unexplored applications of STT-MRAM in robust, low power, cognitive-type systems.

International audience; This paper presents a system design study for wearable sensor devices intended for healthcare and lifestyle applications based on ECG, EEG and activity monitoring. In order to meet the low-power requirement of these applications, a dual-core signal processing system is proposed which combines an ultra-low-power bio-medical Application Specific Instruction-set Processor (BioASIP) and a low-power general-purpose micro-controller (MSP430). To validate the merits of the proposed architecture, system-level power analysis and trade-offs are conducted using real hardware measurements of an ECG R-peak detection application. The results show that the proposed dual-core architecture consumes around 65.38µW, about 25.8x smaller than an MSP430-only approach. Out of 65.38µW, the BioASIP consumes only 11µW and the rest is used in the analog front-end, A/D conversion, and control tasks.

In this paper, Fabless Prototyping Methodology is introduced for the design and analysis of MEMS devices. Conventionally Finite Element Analysis (FEA) is performed before system level simulation. In our proposed methodology, system level simulation is performed earlier than FEA as it is computationally less extensive and low cost. System level simulations are based on equivalent behavioral models of MEMS device. Electrostatic actuation based MEMS Microgripper is chosen as case study to implement this methodology. This paper addresses the behavioral model development and simulation of actuator part of an electrostatically actuated Microgripper. Simulation results show that the actuator part of Microgripper works efficiently for a voltage range of 0-45V with the corresponding jaw displacement of 0-4.5425μm. With some minor changes in design, this range can be enhanced to 15μm at 85V., {"references":["Stephen D. 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Bu tezde, sistem seviyesinde WiMAX benzeticisi gerçekleştirdik. Benzetici, IEEE 802.16 Görev Grubu m tarafından yayınlanan yöntem dokümanı ile uyumludur. Tezde,kutuplaşma kodlarının fiziksel katman soyutlanması üzerine çalıştık ve kutuplaşma kodlarını benzeticiye entegre ettik.Kutuplaşma kodları ile evrişimsel turbo kodların sistem seviyesindeki başarımlarınıkarşılaştırdık ve evrişimsel turbo kodların daha iyi bir başarıma sahip olduğunugözlemledik.Benzetici üzerinde WiMAX'in aşağı bağlantı başarımını farklı yapılanışlarda inceledik.Round robin (RR), proportional fair (PF) ve maximum sum ratio (MSR) olmak üzere, üç farklı kaynak atama yöntemi üzerinde çalıştık. MSR kaynak atama yönteminin veri hızı bakımından en iyi başarıma sahip olduğunu fakat baz istasyonundan uzaktaki kullanıcılara servis veremediğini gözlemledik.13X3, 3X3X1 ve 1X3X1 olmak üzere, üç adet frekans planlama metodu üzerine çalıştık. En yüksek veri hızını 1X3X1 metodunda ve en yüksek spektral verimliliği 1X3X3 metodunda gözlemledik. Bant AMC ve PUSC alt kanal ayrıştırma yöntemleri üzerine çalıştık. Yüksek hızlarda bant AMC'nin PUSC'dan daha iyi başarıma sahip olduğunu, düşük hızlarda ise PUSC'un başarımının daha iyi olduğunu gözlemledik. In this thesis, we implement a WiMAX system level simulator compliant with the evaluation methodology document published by the IEEE 802.16m Task Group. We study the PHY abstraction of polar codes and integrate polar codes intothe simulator. We compare the system level performances of polar code and convolutional turbo code (CTC) and observe that CTC outperforms polar code.On the simulator, we study the downlink (DL) performance of WiMAX under various configurations such as scheduling methods, subchannelization methods, andfrequency reuse models. We study there types of scheduling methods, namely round robin (RR) scheduling, proportional fair (PF) scheduling, and maximum sum rate (MSR) scheduling. We observe that MSR scheduling has the best throughput performance but does not support the users far from the base station. We study three frequency reuse models, namely 1X3X1, 1X3X3, and 3X3X1. We observe that 1X3X1 reuse model has the best throughput performance and maximum spectral efficiency is obtained in 1X3X3 reuse model. We study two subchannelization methods, namely PUSC and band AMC. We observe thatin low mobility cases, band AMC outperforms PUSC and in high mobility cases,PUSC is better than band AMC. 75

Step-up dc-dc converters are being extensively studied due to the diffusion of battery powered, renewable energy, traction systems and electrical power systems applications. Coupled-inductor step-up topology can be efficient when high step-up gains are required. The paper investigates the dependence of the efficiency on design parameters for a bidirectional dc-dc converter. The sliding mode control technique has been selected for controlling the dc-dc bidirectional converter, due to its intrinsic robustness against the uncertainties and disturbances. Analytical models evaluate the power losses thus allowing to calculate the converter efficiency and to make the sensitivity analysis versus the design parameters. Spice numerical simulations, performed with respect to a simple test system, allow to verify the suitability of the proposed modeling and to capture important parasitic phenomena.

In this paper we present system level simulation results of a self-optimizing load balancing algorithm in a long-term-evolution (LTE) mobile communication system. Based on previous work, we evaluate the network performance of this algorithm that requires the load of a cell as input and controls the handover parameters. We compare the results for different simulation setups: for a basic, regular network setup, a non-regular grid with different cell sizes and also for a realistic scenario based on measurements and realistic traffic setup.

In der vorliegenden Arbeit wird eine Prozedur zur Ordnungsreduktion von Finite Elemente Modellen mikromechanischer Struktur mit elektrostatischem Wirkprinzip entwickelt und analysiert. Hintergrund der Ordnungsreduktion ist eine Koordinatentransformation von lokalen Finite Elemente Koordinaten in globale Koordinaten. Die globalen Koordinaten des reduzierten Modells werden durch einige wenige Formfunktionen beschrieben. Damit wird das Makromodell nicht mehr durch lokale Knotenverschiebungen beschrieben, sondern durch globale Formfunktionen, welche die gesamte Deformation der Struktur beeinflussen. Es wird gezeigt, dass Eigenvektoren der linearisierten mechanischen Struktur einfache und effiziente Formfunktionen darstellen. Weiterhin kann diese Methode für bestimmte Nichtlinearitäten und für verschiedene in Mikrosystemen auftretende Lasten angewendet werden. Das Ergebnis sind Makromodelle, die über Klemmen in Systemsimulatoren eingebunden werden können, die Genauigkeiten einer Finite Elemente Analyse erreichen und für Systemsimulationen typische Laufzeitverhalten besitzen.

1 Introduction||2 Design and Verification in LSI System Design||3 Unified HW/SW Co-verification Methodology||4 Fast Co-verification and Design Exploration in Complex Circuits||5 Unified System Level Simulator for Very High Throughput Wireless Systems||6 Conclusion and Future Work, Currently, the complexity of embedded LSI system is growing faster than the productivity of system design. This trend results in a design productivity gap, particularly in tight development time. Since the verification task takes bigger part of development task, it becomes a major challenge in LSI system design. In order to guarantee system reliability and quality of results （QoR）, verifying large coverage of system functionality requires huge amount of relevant test cases and various scenario of evaluations. To overcome these problems, verification methodology is evolving toward supporting higher level of design abstraction by employing HW-SW co-verification. In this study, we present a novel approach for verification LSI circuit which is called as unified HW/SW co-verification framework. The study aims to improve design efficiency while maintains implementation consistency in the point of view of system-level performance. The proposed data-driven simulation and flexible interface of HW and SW design become the backbone of verification framework. In order to avoid time consuming, prone error, and iterative design spin-off in a large team, the proposed framework has to support multiple design abstractions. Hence, it can close the loop of design, exploration, optimization, and testing. Furthermore, the proposed methodology is also able to co-operate with system-level simulation in high-level abstraction, which is easy to extend for various applications and enables fast-turn around design modification. These contributions are discussed in chapter 3. In order to show the effectiveness and the use-cases of the proposed verification framework, the evaluation and metrics assessments of Very High Throughput wireless LAN system design are carried out. Two application examples are provided. The first case in chapter 4 is intended for fast verification and design exploration of large circuit. The Maximum Likelihood Detection （MLD） MIMO decoder is considered as Design Under Test （DUT）. The second case, as presented in chapter 5, is the evaluation for system-level simulation. The full transceiver system based on IEEE 802.11ac standard is employed as DUT. Experimental results show that the proposed verification approach gives significant improvements of verification time （e.g. up to 10,000 times） over the conventional scheme. The proposed framework is also able to support various schemes of system level evaluations and cross-layer evaluation of wireless system., 九州工業大学博士学位論文 学位記番号：情工博甲第328号 学位授与年月日：平成29年6月30日, 平成29年度