Search results for "Broadband"
showing 10 items of 126 documents
Personalized multimedia touristic services for hybrid broadcast/broadband mobile receivers
2010
This paper presents the topology of a multimedia tourism service that targets mobile devices equipped with broadband and either multicast or broadcast access capabilities. Multicast / Broadcast access is used to handle the delivery of multimedia data to many simultaneous users in the service area. The solution adopted is based on existing standards for mobile TV services, but introducing features that enable the provision of generic multimedia services on top of mobile hybrid broadband and broadcast networks. Furthermore, this paper shows how to use standardized interfaces originally defined for interactive mobile TV broadcasting to build personalized mobile multimedia services that do not …
VoiP performance analysis in IEEE802.16 networks
2012
WiMAX, as known as IEEE standard 802.16, is a wide range broadband wireless access network which has a significant good support for the quality of service. According to IEEE standard 802.16e WiMAX has support also for mobility. One of the key advantages of the WiMAX network is the possibility to assign QoS parameters as connection based. A good example of traffic type having strict QoS demands is VoIP. VoIP will probably be a killer application in the future's broadband wireless networks because of its cost efficiency compared to circuit switched networks. In this paper, we analyze by extensive simulations how QoS is applied per connection, especially for the VoIP connection.
Experiencing Broadband Society
2011
Julian Gebhardt, Greif Hajo, Raycheva Lilia, Claire Lobet-Maris & Lasen Amparo (eds), Experiencing Broadband Society (Frankfurt am Main and Oxford: Peter Lang, 2010), 206 pp., ISBN 978-3-631-58406-...
An Integrated Wireless Communication Architecture for Maritime Sector
2011
Published version of a chapter in the book: Multiple Access Communications. Also available from the publisher at http://dx.doi.org/10.1007/978-3-642-23795-9_17 The rapid evolution of terrestrial wireless systems has brought mobile users more and more desired communication services. Maritime customers are asking for the same, such as the concepts of “Broadband at Sea” and “Maritime Internet”. Quite a lot of research work has focused on the development of new and better maritime communication technologies, but less attention has been paid on interworking of multiple maritime wireless networks or on satisfying service provisioning. To address this, an integrated wireless Communication Architec…
Tunable and reconfigurable microwave filter by use of a Bragg-grating-based acousto-optic superlattice modulator
2005
We present an all-optical novel configuration for implementing multitap transversal filters by use of a broadband source sliced by fiber Bragg grating arrays generated by propagating an acoustic wave along a strong uniform fiber Bragg grating. The tunability and reconfigurability of the microwave filter are demonstrated.
Hybrid (diffractive-refractive) optical processor for space-variant color pattern recognition
2002
Space-variant optical processing constitutes an interesting approach in information processing techniques when the location of the reference object is of as much importance as its identification. Applications range from machine vision, optical logic, or neural network systems, to cryptography. First results of positional sensitivity were obtained in the past few years by Fresnel transform correlators with coherent light [1,2]. On the other hand, optical Fresnel cor-relators working under broadband point-source illumination allow us to exploit color information of input scenes and present a discrimination ability higher than its monochromatic counterparts. However, the use of the wavelength …
Analysis of acousto-optic tunable filter performance for imaging applications
2010
Acousto-optic tunable filters (AOTFs) can be used as spec- tral filters in multispectral imaging applications. Acousto-optic crystals diffract a single wavelength from a broadband light beam, depending on the applied radio frequency signal. However, experimental measurements show that the actual performance is far from the expected behavior. We present an experimental characterization of several commercial off-the- shelf AOTFs for the implementation of multispectral imaging instruments. The diffraction performance of three bare crystals is compared, while a fourth AOTF crystal is mounted on the optical path of a multispectral im- ager to evaluate its performance. The experiments show that t…
Accelerating wide-angle converging waves in the near field
2014
We show that a wide-angle converging wave may be transformed into a shape-preserving accelerating beam having a beam-width near the diffraction limit. For that purpose, we followed a strategy that is particularly conceived for the acceleration of nonparaxial laser beams, in contrast to the well-known method by Siviloglou et al (2007 Phys. Rev. Lett. 99 213901). The concept of optical near-field shaping is applied to the design of non-flat ultra-narrow diffractive optical elements. The engineered curvilinear caustic can be set up by the beam emerging from a dynamic assembly of elementary gratings, the latter enabling to modify the effective refractive index of the metamaterial as it is arran…
Broadband focused waves with compensated spatial dispersion: transverse versus axial balance.
2007
We determine the constraints an ABCD optical system must verify to achieve, at the focal region, broadband waves with compensated spatial dispersion either along the optical axis, called on-axis isodiffracting fields, or in the lateral direction, here named in-plane isodiffracting beams. An optical configuration is identified for generating both types of achromatic broadband focused wave fields. An experimental verification is also provided.
Data service platform for sentinel-2 surface reflectance and value-added products: System use and examples
2016
This technical note presents the first Sentinel-2 data service platform for obtaining atmospherically-corrected images and generating the corresponding value-added products for any land surface on Earth (http://s2.boku.eodc.eu/). Using the European Space Agency’s (ESA) Sen2Cor algorithm, the platform processes ESA’s Level-1C top-of-atmosphere reflectance to atmospherically-corrected bottom-of-atmosphere (BoA) reflectance (Level-2A). The processing runs on-demand, with a global coverage, on the Earth Observation Data Centre (EODC), which is a public-private collaborative IT infrastructure in Vienna (Austria) for archiving, processing, and distributing Earth observation (EO) data (http://www.…