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In this work, a free space optical (FSO) link for the ground-to-train communications is proposed. Analytical analysis is carried out for the case of the straight track as well as curved rail tracks. We show that the transmitter divergence angle, the transmit power and the size of the concentration lens needs to increase for the curved section of the rail track compared to the straight track. We derive...
In this paper we focus in the analysis of the FSO link performance under sandstorms conditions. The sandstorms are characterized by the size of the particles and the necessary wind speed in order to blowing them up during a minimum period of time. Sandstorm is a well know problem in many parts of the world and different reports has been presented regarding the impairments that sandstorms produces...
This work focuses on the design approach for a dual-polarized ultrawideband (UWB) patch antenna targeting the frequency range 3.5 – 4.5 GHz. The architecture described in this paper uses the square ring slot feeding approach to increase its bandwidth. In the first part of the manuscript, a tuning analysis of the antenna properties with respect to its geometrical parameters is provided. The second...
This work focuses on the design approach for a dual-polarized ultrawideband (UWB) patch antenna targeting the frequency range 3.5 – 4.5 GHz. The architecture described in this paper uses the square ring slot feeding approach to increase its bandwidth. In the first part of the manuscript, a tuning analysis of the antenna properties with respect to its geometrical parameters is provided. The second...
The terrestrial free space optical (FSO) link promises a number of advantages in terms of higher data rates and license free bandwidth, but is challenged by atmospheric propagation conditions. Designing a system for the worst channel conditions leads to an inadequate use of resources while opting for a system design based on clear sky conditions lacks reliability. The key idea behind this work is...
New results derived from the research in the field or Free Space Optics (FSO) for the qualification of different wavelengths with reference to future communication (including space) are presented. The contribution deals with a thorough discussion of the different optical wavelengths used either for terrestrial as well as for near-Earth and deep space FSO links. Practical results of COST Action IC-0802...
The Coupled Dark State Magnetometer (CDSM) is an optically-pumped absolute scalar magnetometer which is based on two-photon spectroscopy of free alkali atoms. Several magnetic field dependent resonances occur in the presence of an external magnetic field, reaching their maximal strengths at different angles between the magnetic field direction and the reference axis of the sensor defined by the optical...
Sensitive detectors and large receiver apertures offer high efficiency at the receiver of Free Space Optics (FSO) systems. The receiver aperture can be increased by employing larger lenses, telescopes and mirrors, but also with tapers (glass-cones). Tapers are collecting and guiding the incoming light directly to the fibre at the receiver. In this contribution, the use of optical tapers as couplers...
In this paper, we analyze the behavior of DVB-S2 un-punctured/punctured low-density parity-check (LDPC) coded on-off-keying (OOK) under atmospheric turbulence conditions by utilizing time diversity. A performance characterization between these schemes is evaluated, where punctured LDPC code provides a penalty of around 0.1 to 0.2 dB against unpunctured LDPC codes but still provides a coding gain of...
A new ultra wideband (UWB) power divider is proposed in this paper. A design of the power divider is based on coupled transmission lines and it has been implemented using low temperature cofired ceramic (LTCC) technology. The power divider provides a function over the whole UWB bandwidth (3.1-10.6GHz). In contrary to commonly used coupled line splitters, the design doesn't requires infinite increasing...
The growing need for network capacity due to peer-to-peer (P2P) users causes tremendous costs for Internet service providers (ISPs). Traffic shaping schemes have been applied to limit P2P traffic while reducing customer satisfaction and affecting the performance of other applications. As an alternative, in this work we propose the use of inexpensive free-space optical (FSO) links from ISPs to fibre...
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