55 research outputs found
Measurement-Based Characterization of 39 GHz Millimeter-Wave Dual-Polarized Channel Under Foliage Loss Impact
This paper presents a measurement-based analysis of wideband 39 GHz millimeter wave (mm-wave) dual-polarized propagation channel under the impact of foliage presence between a transmitter (Tx) and a receiver (Rx). The measurements were conducted in a rich-vegetation area, and the so-called direction-scan-sounding (DSS) method which rotates a horn antenna in angular domains was applied, aiming at investigating the direction-of-arrival (DoA)-dependent characteristics of polarimetric channels. Four Tx-to-Rx polarization configurations were considered, including co-polarization scenarios with vertical Tx-polarization to vertical Rx-polarization (VV) and horizontal to horizontal (HH), as well as cross-polarization with vertical to horizontal (VH) and horizontal to vertical (HV), which allow scrutinizing the differences in delay-direction dispersion for usually-encountered scenarios. A foliage loss model for various vegetation depths in VV polarization configuration, was also presented in this paper. The results show that the foliage-loss DoA spectra for VH and HV are similar, while the spectra exhibit less penetration loss in most directions for VV than for the HH. Furthermore, the presence of vegetation between the Tx and the Rx leads to larger dispersion in delay compared to the clear line-of-sight (LoS) scenario, particularly for vertical polarization in the Tx side, and additionally, the foliage presence also results in evident DoA dispersion, specially in the HV scenario. Selectivity in directions caused by foliage is more significant in vertically-polarized Tx scenarios than in the horizontally-polarized Tx scenarios. A statistical model is established summarizing these comparison details
Dynamic Channel Modeling for Indoor Millimeter-Wave Propagation Channels Based on Measurements
In this contribution, a recently conducted measurement campaign for indoor millimeter-wave propagation channels is introduced. A vector network analyzer (VNA)-based channel sounder was exploited to record the channel characteristics at the frequency band from 28-30 GHz. A virtual uniform circular array (UCA) with a radius of 0.25m was formed using a rotator with 360 steps. Moreover, by taking advantage of fiber-optic technique applied in the channel sounder, measurements at 50 positions were performed from an indoor hall to an indoor corridor along a long pre-defined route. A low-complexity highresolution propagation estimation (HRPE) algorithm is exploited to estimate the propagation parameters of multipath components (MPCs). Based on the HRPE estimation results, a novel clustering identification and tracking algorithm is proposed to trace clusters. Composite channel characteristics, cluster-level characteristics and dynamic (or birth-death) behaviours of the clusters are investigated, which constitute a dynamic model for the indoor millimeter-wave channel
A review of manufacturing materials and production methods for frequency-selective structures [wireless corner]
This article presents a review of frequency-selective structure (FSS) manufacturing materials and production methods ranging from the common printed circuit board (PCB)-based designs to textile, ink, metal, or fluid prototypes. Our work gathers some of the most relevant solutions published by the scientific community and considers several examples depicted for each case. Additionally, the main physical parameters that may have a significant impact on FSS performance have been identified, e.g., electrical conductivity of the FSS conductive element and the relative permittivity and thickness of the FSS dielectric material. Finally, a comparative analysis of the materials and techniques is presented, which highlights the benefits and limitations of each solution.Fundação para a CiĂȘncia e a Tecnologia | Ref. POCI-01- 0247-FEDER- 017867Ministerio de EconomĂa y Competitividad | Ref. TEC2014-55735-C03-
Empirical multi-band characterization of propagation with modelling aspects for communictions
Diese Arbeit prĂ€sentiert eine empirische Untersuchung der Wellenausbreitung fĂŒr drahtlose Kommunikation im Millimeterwellen- und sub-THz-Band, wobei als Referenz das bereits bekannte und untersuchte sub-6-GHz-Band verwendet wird. Die groĂen verfĂŒgbaren Bandbreiten in diesen hohen FrequenzbĂ€ndern erlauben die Verwendung hoher instantaner Bandbreiten zur ErfĂŒllung der wesentlichen Anforderungen zukĂŒnftiger Mobilfunktechnologien (5G, â5G and beyondâ und 6G). Aufgrund zunehmender Pfad- und Eindringverluste bei zunehmender TrĂ€gerfrequenz ist die resultierende Abdeckung dabei jedoch stark reduziert. Die entstehenden Pfadverluste können durch die Verwendung hochdirektiver Funkschnittstellen kompensiert werden, wodurch die resultierende Auflösung im Winkelbereich erhöht wird und die Notwendigkeit einer rĂ€umlichen Kenntnis der Systeme mit sich bringt: Woher kommt das Signal? DarĂŒber hinaus erhöhen gröĂere Anwendungsbandbreiten die Auflösung im Zeitbereich, reduzieren das small-scale Fading und ermöglichen die Untersuchung innerhalb von Clustern von Mehrwegekomponenten. Daraus ergibt sich fĂŒr Kommunikationssysteme ein vorhersagbareres Bild im Winkel-, Zeit- und Polarisationsbereich, welches Eigenschaften sind, die in Kanalmodellen fĂŒr diese Frequenzen widergespiegelt werden mĂŒssen. Aus diesem Grund wurde in der vorliegenden Arbeit eine umfassende Charakterisierung der Wellenausbreitung durch simultane Multibandmessungen in den sub-6 GHz-, Millimeterwellen- und sub-THz-BĂ€ndern vorgestellt. Zu Beginn wurde die Eignung des simultanen Multiband-Messverfahrens zur Charakterisierung der Ausbreitung von Grenzwert-Leistungsprofilen und large-scale Parametern bewertet. AnschlieĂend wurden wichtige Wellenausbreitungsaspekte fĂŒr die Ein- und Multibandkanalmodellierung innerhalb mehrerer SĂ€ulen der 5G-Technologie identifiziert und Erweiterungen zu verbreiteten rĂ€umlichen Kanalmodellen eingefĂŒhrt und bewertet, welche die oben genannten Systemaspekte abdecken.This thesis presents an empirical characterization of propagation for wireless communications at mm-waves and sub-THz, taking as a reference the already well known and studied sub-6 GHz band. The large blocks of free spectrum available at these high frequency bands makes them particularly suitable to provide the necessary instantaneous bandwidths to meet the requirements of future wireless technologies (5G, 5G and beyond, and 6G). However, isotropic path-loss and penetration-loss are larger with increasing carrier frequency, hence, coverage is severely reduced. Path-loss can be compensated with the utilization of highly directive radio-interfaces, which increases the resolution in the angular domain. Nonetheless, this emphasizes the need of spatial awareness of systems, making more relevant the question âwhere does the signal come from?â In addition, larger application bandwidths increase the resolution in the time domain, reducing small-scale fading and allowing to observe inside of clusters of multi-path components (MPCs). Consequently, communication systems have a more deterministic picture of the environment in the angular, time, and polarization domain, characteristics that need to be reflected in channel models for these frequencies. Therefore, in the present work we introduce an extensive characterization of propagation by intensive simultaneous multi-band measurements in the sub-6 GHz, mm-waves, and sub-THz bands. Firstly, the suitability of the simultaneous multi-band measurement procedure to characterize propagation from marginal power profiles and large-scale parameters (LSPs) has been evaluated. Then, key propagation aspects for single and multi-band channel modelling in several verticals of 5G have been identified, and extensions to popular spatial channel models (SCMs) covering the aforementioned system aspects have been introduced and evaluated
1-D broadside-radiating leaky-wave antenna based on a numerically synthesized impedance surface
A newly-developed deterministic numerical technique for the automated design of metasurface antennas is applied here for the first time to the design of a 1-D printed Leaky-Wave Antenna (LWA) for broadside radiation. The surface impedance synthesis process does not require any a priori knowledge on the impedance pattern, and starts from a mask constraint on the desired far-field and practical bounds on the unit cell impedance values. The designed reactance surface for broadside radiation exhibits a non conventional patterning; this highlights the merit of using an automated design process for a design well known to be challenging for analytical methods. The antenna is physically implemented with an array of metal strips with varying gap widths and simulation results show very good agreement with the predicted performance
Beam scanning by liquid-crystal biasing in a modified SIW structure
A fixed-frequency beam-scanning 1D antenna based on Liquid Crystals (LCs) is designed for application in 2D scanning with lateral alignment. The 2D array environment imposes full decoupling of adjacent 1D antennas, which often conflicts with the LC requirement of DC biasing: the proposed design accommodates both. The LC medium is placed inside a Substrate Integrated Waveguide (SIW) modified to work as a Groove Gap Waveguide, with radiating slots etched on the upper broad wall, that radiates as a Leaky-Wave Antenna (LWA). This allows effective application of the DC bias voltage needed for tuning the LCs. At the same time, the RF field remains laterally confined, enabling the possibility to lay several antennas in parallel and achieve 2D beam scanning. The design is validated by simulation employing the actual properties of a commercial LC medium
Millimetriaaltopohjainen runkoyhteys ultratiheille langattomille verkoille - Itseasentuvien verkkoelementtien analyysi
The amount of wireless traffic and number of connected devices are expected to explode in the coming future. By the year 2020 the amount of data traffic is forecasted to grow 1000 times from 2010 levels and the amount of connected devices is expected to reach 50 billion. One reason to these numbers is massive increase in machine type communications. 5G networks have been envisioned to address these challenges.
In the 5G network concept the networks are getting denser than ever before. Millimeter wave communications play an important role in backhauling of the mobile traffic as deploying optical fiber to every small node is most likely going to be too cost intensive for operators.
Efficient deployment of an ultra-dense wireless network requires that the devices support so called âplug and playâ installation. In practice it means that a mechanic installing a new radio node should only perform physical mounting of the device. Antenna alignment and link setup processes should be fully automated.
The purpose of this thesis is to study practical issues and possible solutions of realizing the plug and play installation in a cost efficient way. This study will define scenarios and functional requirements of adding access nodes to backhaul networks. Technical evaluation of link discovery process and cost analysis on plug and play installation of access nodes are conducted.Tulevaisuudessa langattomien laitteiden mÀÀrÀn ja niiden generoiman liikenteen odotetaan kasvavan rÀjÀhdysmÀisesti. Vuoteen 2020 mennessÀ verkoissa siirrettÀvien datamÀÀrien on ennustettu kasvavan tuhatkertaisiksi vuoden 2010 tasosta, ja liitettyjen laitteiden mÀÀrÀn odotetaan nousevan 50 miljardiin. Yksi syy nÀihin on koneiden vÀlisen viestinnÀn massiivinen kasvu. 5G-verkkoja on kaavailtu vastaamaan edellÀ mainittuihin haasteisiin.
Osana 5G-konseptia verkkojen odotetaan rakentuvan tiheÀmmiksi kuin koskaan aiemmin. Millimetriaaltoihin pohjautuvat linkit tulevat olemaan merkittÀvÀssÀ roolissa mobiilidatan siirtÀmisessÀ radionoodeista runkoverkkoon, koska optisen kuidun rakentaminen jokaiselle pienelle noodille tulisi mitÀ luultavimmin operaattoreille liian kalliiksi.
Ultratiheiden verkkojen tehokas rakentaminen vaatii, ettÀ asennettavat laitteet tukevan niin sanottua itseasennusta. KÀytÀnnössÀ se tarkoittaa sitÀ, ettÀ asentajan tÀytyy ainoastaan suorittaa radionoodin fyysinen asennus. Antenniensuuntaus- ja linkinmuodostusprosessien tulisi olla tÀysin automatisoituja.
TÀmÀn diplomityön tarkoituksena on tutkia kustannustehokkaaseen itseasennukseen liittyviÀ kÀytÀnnön ongelmia sekÀ mahdollisia ratkaisuita. Tutkimus mÀÀrittelee skenaariot ja funktionaaliset vaatimukset radionoodien lisÀÀmiseksi osaksi operaattorin verkkoa. Työ sisÀltÀÀ linkkienmuodostusprosessin teknisen evaluoinnin, sekÀ kustannusanalyysin tiheiden verkkojen rakentamisesta hyödyntÀen itseasennustekniikkaa
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