Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 21 for “"rain attenuation"”.
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Modeling the dynamic behavior of rain attenuation
… the problem of predicting satellite path rain fade duration statistics for an arbitrary location, frequency, elevation angle and polarization. It summarizes the development of a dynamic stochastic model. From this model a technique is derived for predicting fade duration statistics for one …
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The dynamic behavior of rain attenuation on satellite communication links
… research into the effects of atmospheric rain and ice on the reception of these signals. This thesis examines the statistics of fade rate, fade duration, and interface intervals on 19 and 28 GHz communication links, at an elevation angle of 45 degrees. The study uses 2 years of data …
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Estimation of rain attenuation on earth-space millimeter wave communications links
An easy to use model for calculating rain attenuation along earth-space millimeter wave communications links is proposed. The model computes attenuation as a function of point rainfall intensity for a given frequency, path elevation angle, and earth station latitude and altitude. Estimates of the …
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Frequency scaling of rain attenuation on satellite links in the Ku/Ka-bands using OLYMPUS satellite data
Frequency scaling of attenuation is the prediction of attenuation at a desired frequency from attenuation values at a base frequency. The attenuation at the base frequency is often known from prior measurements. Frequency scaling of attenuation is of interest because of the eventual need to exploit …
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Rain attenuation and depolarization along 10 to 30 GHz earth space links predicted from s-band dual-polarized radar measurements
… model FORWP that is capable of predicting attenuation and cross polarization at 10-30 GHz from dual-polarization radar data with a high degree of accuracy. FORWP uses a rigorous backscattering computer model BSCAT to infer rain drop size distribution along the slant path from radar measured …
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Satellite Channel State Prediction based on Fade Slope and Artificial Intelligence (AI) Algorithms
… But these frequency bands become susceptible to attenuation during rainfall. The resulting rain attenuation sometimes exceeds what can be mitigated by providing sufficient fixed fade margin.<br/><br/>Therefore, there is a need for adaptive fade mitigation techniques (AFMTs), to compensate for the …
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Modelling of Rainfall Drop Size Distributions for Application in Fade Prediction on Earth-Space Paths
… becomes highly susceptible to disruption by rain during each satellite pass when path elevation angles will range anywhere between 90 degrees and 20 degrees or less. The resulting rain attenuation will sometimes exceed what can be feasibly combated through link dimensioning to include a …
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Time Diversity Modelling and Implementation for Broadcast Satellite Systems at V-band
… these services can be severely impaired by rain induced attenuation. Hence, this thesis presents time diversity (TD) as a highly promising link restoration scheme that makes for efficient use of higher frequency bands without imposing unrealistically high fixed propagation margins on the …
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Wideband Terrestrial Path Loss Measurement Results For Characterization of Pico-cell Radio Links at 38 GHz and 60 GHz Bands of Frequencies
… during different weather conditions, especially rain. This research attempts to characterize the performance of pico-cell scenario broadband wireless channels by measuring path loss statistics during different weather conditions. Hardware and software components of a wideband direct-sequence …
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Assessing the technical and financial viability of broadband satellite systems using a cost per T1 minute metric
… power resources, achievable link margins, and rain attenuation. A computer simulation is developed to model the complex interactions between the capacity limits and distributed market models.
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Multiple scattering of electromagnetic waves by distributions of particles with applications to radio wave propagation through precipitation
… equation is applied to ice depolarization and rain attenuation and depolarization. Twersky's procedure is then extended in order to derive a vector-valued Dyson equation and a tensor-valued two-frequency BetheSaltpeter equation for waves propagating in a distribution of spatially pair …
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Adaptive Digital Predistortion with Applications for LMDS Systems
… is the limited distance of current systems. Rain attenuation and limited transmitter power are the primary causes of the limited distance. Adaptive digital predistortion is presented as a method of increasing effective transmitter power. A background on LMDS link design, non-linear …
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Statistical correlation as a tool in propagation studies
… millimeter wave propagation through rain and ice crystals. The technique presented involves correlating dB values of the satellite signal attenuation and polarization isolation with dBZ values of radar backscatter from each of 128 range gates. In it, Pearson product moment correlation …
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Išorinio poveikio įtaka terahercų taikymams telekomunikacijose /
… were examined in terms of the atmospheric attenuation, mostly rain attenuation and variations of atmospheric refractive index. Also, one of the most probable technological scenarios (short distances and quasi-optical transmission) was investigated. The results were compared with data from a …
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Impact of external effects on terahertz applications for telecommunications /
… were examined in terms of the atmospheric attenuation, mostly rain attenuation and variations of atmospheric refractive index. Also, one of the most probable technological scenarios (short distances and quasi-optical transmission) was investigated. The results were compared with data from a …
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System Design of an Integrated Terrestrial-Satellite Communications Network for Disaster Recovery
… including adjacent satellite interference, rain attenuation, antenna pointing error, noise temperature, and modulation and multiple access selection, were addressed.
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Channel prediction and adaptation over satellite channels with weather-induced impairments
Bad weather conditions, especially due to rain, cause satellites operating at high frequencies (above 10 GHz) to have significant link attenuation. Usually extra link margins are used to assure link availability. These margins cause inefficient use of precious satellite and terminal power, and …
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A Wind and Rain Backscatter Model Derived from AMSR and SeaWinds Data
… algorithm for simultaneously retrieving wind and rain (SWR) from scatterometer measurements was developed that enables SeaWinds to correct rain-corrupted wind measurements and retrieve rain rate data. This algorithm is based on co-locating Tropical Rainfall Measuring Mission Precipitation Radar …
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Fusion of observations from C-band polarimetric radar and S-band profiler radar during a convective storm
… discusses a procedure to measure and correct attenuation of the radar signals caused by the presence of partially melted ice hydrometeors (graupels and hails) in convective storms by utilizing simultaneous observations from a C-Band dual-polarization scanning radar and a vertically pointing …
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The study and real-time implementation of attenuation correction for X-band dual-polarization weather radars
Attenuation of electromagnetic radiation due to rain or other wet hydrometeors along the propagation path has been studied extensively in the radar meteorology community. Recently, use of short range dual-polarization X-band radar systems has gained momentum due to lower system cost compared with …
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