Now showing items 216-235 of 345

    Network coding-aided MAC protocols for cooperative wireless networks 

    Antonopoulos, Angelos (Date of defense: 2012-12-17)

    The introduction of third generation (3G) technologies has caused a vast proliferation of wireless devices and networks, generating an increasing demand for high level Quality of Service (QoS). The wide spread of mobile ...

    Network virtualization in next generation cellular networks 

    Tseliou, Georgia (Date of defense: 2019-07-17)

    The complexity of operation and management of emerging cellular networks significantly increases, as they evolve to correspond to increasing QoS needs, data rates and diversity of offered services. Thus critical challenges ...

    New generation FTTH ONU and OLT design for upstream transmission in WDM PON including optimized combination of electronics and optics 

    Omella Cancer, Mireia (Date of defense: 2010-10-18)

    This research is developed in the context of the Next Generation of Passive Optical Networks (NG-PON) for Fibre to the Home (FTTH) network. In this thesis, several techniques are proposed in order to increase the network ...

    Next generation multibeam satellite systems 

    Joroughi, Vahid (Date of defense: 2015-12-02)

    Satellite communication will play a central role towards fulfilling next generation 5G communication requirements. As a matter of fact, anytime-anywhere connectivity cannot be conceived without the presence of the satellite ...

    Next generation optical access networks and coexistence with legacy PONs 

    Velásquez Micolta, Juan Camilo (Date of defense: 2019-07-25)

    Nowadays, Fiber-to-the-Home is one of the most promising solutions to provide broadband services in access networks. However, the fiber is inefficiently used as most of the deployed systems are still based on Time Division ...

    Next generation passive optical networks based on orthogonal frequency division multiplexing techniques 

    Escayola Elias, Francesc Xavier (Date of defense: 2015-12-11)

    In recent decades, the industry of communications has acquired huge significance, and nowadays constitutes an essential tool for the society information. Thus, the exponential growth in demand of broadband services and ...

    Nonlinear analysis of electro-acoustic frequency-selective devices for communications 

    García Pastor, David (Date of defense: 2021-03-09)

    Nowadays, mobile devices have become a key technology in our lives, making us become part of a connected world, in which millions of mobile handsets are sold every year. In order to satisfy the user demands, many mobile ...

    Nonlinear mechanisms in passive microwave devices 

    Rocas Cantenys, Eduard (Date of defense: 2011-06-22)

    The telecommunications industry follows a tendency towards smaller devices, higher power and higher frequency, which imply an increase on the complexity of the electronics involved. Moreover, there is a need for extended ...

    Nonlinear modeling and characterization of SAW devices for communications systems 

    González Rodríguez, Marta (Date of defense: 2023-02-10)

    (English) Nowadays, worldwide booming growth in mobile devices puts a lot of pressure on the mobile communications technologies since an enormous amount of requirements, mainly focused on delivering enhanced mobile broadband ...

    Nonlinear simulation and design of microwave, multi-device distributed autonomous circuits 

    Acampora, Alessandro (Date of defense: 2013-07-30)

    It is widely believed that many drawbacks in today's wireless communication paradigm might be relieved by enabling high carrier frequency transmission, and endowing both the network and the user equipment with some degree ...

    Normalización estadística para fusión biométrica multimodal 

    Ejarque Monserrate, Pascual (Date of defense: 2011-03-17)

    Los sistemas de reconocimiento biométrico utilizan ciertas características humanas como la voz, los rasgos faciales, la huella dactilar, el iris o la geometría de la mano para identificar a un individuo o verificar su ...

    Nuevas técnicas diagnósticas de las enfermedades respiratorias : análisis de imagen 

    Fiz Fernández, José Antonio (Date of defense: 2016-07-13)

    In the present thesis 3 detailed studies were carried out that spring from 3 different diagnostic techniques that include bronoscopy, tuberculine bacillus infection diagnosis, and the control of oxygen therapy in chronic ...

    Nuevo método de detección espectral para sistemas multiportadoras basado en la radio cognitiva 

    Rojas Hernández, Miguel Ángel (Date of defense: 2019-11-20)

    Nowadays, the growing demand for frequency-free bands for new emerging wireless technologies and fixed frequency allocation policies in the use of the radio spectrum have resulted in a saturation of the radio frequency ...

    Ocean monitoring using L-Band microwave radiometry and GNSS-R 

    Valencia Domènech, Enric (Date of defense: 2012-10-17)

    The knowledge of sea surface salinity (SSS) is a key issue to understand and monitor the Earth¿s water cycle. Accurate and systematic measurement of SSS was not possible until the ESA¿s Soil Moisture and Ocean Salinity ...

    Ocean surface currents reconstruction from microwave radiometers measurements 

    González Haro, Cristina (Date of defense: 2015-05-22)

    Ocean currents are a key component to understanding many oceanic and climatic phenomena and knowledge of them is crucial for both navigation and operational applications. Therefore, a key problem in oceanography is the ...

    On the design of high-efficiency RF Doherty power amplifiers 

    Yahyavi, Mehran (Date of defense: 2016-03-18)

    Power amplifiers (PAs) are one of the most crucial elements in wireless standards becasue they are the most power hungry subsystems. These elements have to face an important issue, which is the power efficiency, a fact ...

    On the design of microwave radiometers with digital beamforming and polarization synthesis for earth observation. 

    Bosch Lluis, Xavier (Date of defense: 2011-03-30)

    Actualment, la comunitat científica ja disposa de les primeres mesures radiomètriques a banda L, polarimètriques i multi-angulars fetes de l’espai. Això és gràcies al recent llançament de la missió de la Eurepean Space ...

    On the detection of ionospheric waves, relationship with earthquakes and tsunamis 

    Yang, Heng, 1985- (Date of defense: 2019-06-11)

    The research of this thesis addresses the detection and characterization of ionospheric waves and its application to traveling ionospheric disturbances (TIDs) induced by the natural events, such as earthquakes and tsunamis. ...

    On the resource abstraction, partitioning and composition for virtual GMPLS-controlled multi-layer optical networks 

    Vilalta Cañellas, Ricard (Date of defense: 2013-12-03)

    Virtual optical networking supports the dynamic provisioning of dedicated networks over the same network infrastructure, which has received a lot of attention by network providers. The stringent network requirements (e.g., ...

    Opportunistic communications in large uncoordinated networks 

    Borràs Pino, Jordi (Date of defense: 2023-01-25)

    (English) The increase of wireless devices offering high data rate services limits the coexistence of wireless systems sharing the same resources in a given geographical area because of inter-system interference. Therefore, ...