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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Concealment Materials and Techniques for mm-Wave Advanced Antenna Systems

Bharadwaj Sriram, Adhitya January 2018 (has links)
With the advent of the 5G technology standard for communication, it is esti-mated that around 50 billion devices around the world will be interconnectedunder this standard [1]. This has prompted the need to investigate new ma-terials, technologies and methods to conceal antennas for preserving the aes-thetic value of urban centers, and preventing these antenna systems from beingidentified or damaged. The aim of this thesis work was to identify possiblematerials and investigate methods for concealing Ericsson’s 5G mm-Wave Ad-vanced Antenna System(AAS) Radio Base Stations. A study of economicallyviable, commercially available materials for concealment, and methods to deter-mine their dielectric properties was done. A practical investigation of the effectsome available concealment materials on the RF performance of the mm-Wavebase station beams, was also performed. The results from the investigationsand measurements performed led to some useful conclusions and understand-ing about the various concealment material solutions. Overall, the investigatedconcealment materials were found to have two prominent effects:1. Reduction in EIRP (Equivalent Isotropic Radiated Power) of the basestation beams (attenuation).2. Distortion in the shape of the base station beams.The boresight beams for all the investigated cases were found to be attenu-ated(effect 1) by the concealments, but the steered beams were found to beboth attenuated in distorted(effect 2) by the concealments. In particular, con-cealments with a thin dielectric material mesh structure were found to have theleast effect on the base station beams. All other thicker(> λ0/2), compositeconcealments and even those with pure foam structures, were found to have anoticeable effect on the base station beams. In conclusion, thin dielectric mesh,films and paints could hence be of interest as concealment solutions for furtherinvestigations moving forward. / I och med införandet av 5G-tekniken för kommunikation bedöms det att cirka50 miljarder enheter runt om i världen kommer att vara uppkopplade via denna standard [1]. För att bevara det estetiska värdet av stadscentrum och förhindra att 5G-teknikens antenner identifieras eller skadas finns behov att undersöka nya material, tekniker och metoder för att dölja antenner. I detta examensarbete identifieras möjliga material samt undersöks metoder för att dölja Ericssons 5G mm-vågs Advanced Antenna System (AAS) radiobasstationer. Enstudie av ekonomiskt genomförbara, kommersiellt tillgängliga material för döljande och metoder för bestämning av dess dielektriska egenskaper gjordes. En empirisk undersökning av effekten av några tillgängliga maskeringsmaterial på RF-prestanda hos loberna från mm-vågsbasstationer utfördes också. Resultaten från de undersökningar och mätningar som utfördes ledde till några användbara slutsatser och förståelse för egenskaperna hos de olika maskeringsmaterialen. Sammantaget visade sig de undersökta maskeringsmaterialen ha två huvudsakliga effekter:1. Dämpning av EIRP (ekvivalent isotropisk utsrålad effekt) hos basstationsloberna.2. Distorsion av basstationslobernas form.De centrala basstationsloberna för alla undersökta fall visade sig dämpas (ef-fekt 1) av maskeringsmaterialen, men de utstyrda loberna befanns vara både dämpade och förvrängda (effekt 2) av maskeringsmaterialen. Maskeringsmaterial med en tunn dielektrisk nätstruktur visade sig ha den minsta effekten på basstationsloberna. Alla andra tjockare, sammansatta material och ävende med rena skumstrukturer visade sig ha en märkbar effekt på basstation-sloberna. Sammanfattningsvis kan därför tunna dielektriska nät, filmer (plastfolier) och färger vara av intresse som lösningar för vidare undersökningar.
2

Study of smart antennas and MU-MIMO techniques for indoor radio engineering and planning tools / Prise en compte des antennes adaptatives et techniques MIMO multiutilisateurs pour l'ingénierie et les outils d'ingénierie radio indoor

Issiali, Khouloud 08 December 2015 (has links)
La facilité de déploiement et la flexibilité des technologies sans fil ont permis une évolution considérable des normes IEEE 802.11. L'arrivée de la fibre optique à la maison a également motivé des études de recherche pour accroître les débits et la capacité. Dans ce contexte, la dernière norme IEEE 802.11ac ratifiée en 2014 a normalisé de nouvelles technologies pour atteindre des débits maximaux au-dessus de 1Obit/s. En particulier, 802 llac propose le Multiple Input Multiple Output Multi-Utilisateurs (MIMO-MU) et le Transmit Beamforming (TxBF). Ces technologies d'antennes intelligentes supposent un diagramme d'antenne d'émission qui dépend de la position des utilisateurs et des caractéristiques du canal de propagation multi-trajets correspondant. Cependant, les outils d'ingénierie et de planification radio actuels simulent une carte de couverture fixe et indépendante de tout traitement d'antennes adaptatives côté émission. Cette thèse étudie l'impact de ces techniques MIMO-MU et TxBF et propose des solutions adaptées pour l'ingénierie radio et l'optimisation du système ainsi que pour les outils de planification radio. En effet, la première partie de cette thèse consiste à affiner les gains de capacité en identifiant les configurations et les paramètres système optimaux. La deuxième partie aborde les gains de beamforming en termes du gain sur le rapport signal à bruit (SNR) et sur la réduction du niveau d'interférence pour avoir une modélisation réaliste de la couverture radio. / The deployment facility and flexibility of wireless technologies have allowed considerable evolution of IEEE 802 .11 standards. The arrival of the optical fiber to the home has further motivated the research studies to increase data rates and capacity. ln this context, the latest IEEE 802.l lac standard ratified in 2014 proposes new technologies to achieve maximum data rates above 1 Gbit/s. ln particular, 802.l lac includes the Multi-User Multiple Input Multiple Output (MU-MIMO) and Transmit Beamforming (TxBF). These smart antenna technologies assume a variable transmit antenna pattern in function of the users' position and the corresponding multipath propagation channel characteristics. However, the actual radio planning tools give a fixed coverage map in dependent of any adaptive or smart antenna processing. This thesis studies the impact of the MU-MIMO and TxBF techniques on radio engineering, system optimization as well as radio planning tools. Indeed, the first part of this thesis deals with refining the sum rate capacity gains by identifying interesting system configurations and optimal system parameters. The second part addresses the beamforming gains in terms of the Signal-to-Noise Ratio (SNR) gain and interference level to have realistic radio coverage modeling.

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