scholarly journals Coverage Determination of Incumbent System and Available TV White Space Channels for Secondary Use in Ethiopia

2021 ◽  
Author(s):  
Habib Mohammed ◽  
Tessema T. Terefe ◽  
Sultan Feisso
Keyword(s):  
Path Loss ◽  
Propagation Model ◽  
Frequency Variation ◽  
Electromagnetic Spectrum ◽  
White Space ◽  
Case Scenario ◽  
Worst Case ◽  
Tv White Space ◽  
Secondary Use ◽  
Different Response

Different path loss modelsare used to analyze the behavior of terrestrial television signals. The path loss calculated by one model differs from the other depending on different factors they consider. Frequency is one of the main factors included in each model. The frequency variation in the electromagnetic spectrum causes different response for each model. In terrestrial TV signal representation, since it is operating under VHF and UHF spectrum range, the propagation model used to model the signal must be less invariant when the transmitter is operating in VHF and UHF. If the pathloss model used is very variant it is difficult to define the coverage of the transmitters. This causes interference among transmitters and between the digital terrestrial TV transmitters and TV white space devices. Different propagation models are analyzed by their sensitivity to frequency variation from very-high and ultra-high frequency spectrums. After the best model is selected, we have used this model to find the coverage of the incumbent transmitter, which then is used to analyze free channels for secondary use. First the pathloss at VHF and then for UHF is calculated. This difference is then compared and the result indicates that ITU-R P.1546–5, which incorporate terrain data is best of others. Using this model and further analyze the coverage and free channels, we have found a minimum of 408 MHz free contiguous bandwidth, by considering a worst-case scenario, which is placing a WSD at the incumbent transmitter.

scholarly journals Path Loss Determination Using Linear and Cubic Regression Inside a Classic Tomato Greenhouse

2019 ◽  
Vol 16 (10) ◽  
pp. 1744 ◽  
Author(s):  
Dora Cama-Pinto ◽  
Miguel Damas ◽  
Juan Antonio Holgado-Terriza ◽  
Francisco Gómez-Mula ◽  
Alejandro Cama-Pinto
Keyword(s):  
Precision Agriculture ◽  
Path Loss ◽  
Field Tests ◽  
Substantial Improvement ◽  
Radio Waves ◽  
Case Scenario ◽  
Worst Case ◽  
Propagation Models ◽  
Deployment Planning ◽  
Error Percentage

The production of tomatoes in greenhouses, in addition to its relevance in nutrition and health, is an activity of the agroindustry with high economic importance in Spain, the first exporter in Europe of this vegetable. The technological updating with precision agriculture, implemented in order to ensure adequate production, leads to a deployment planning of wireless sensors with limited coverage by the attenuation of radio waves in the presence of vegetation. The well-known propagation models FSPL (Free-Space Path Loss), two-ray, COST235, Weissberger, ITU-R (International Telecommunications Union—Radiocommunication Sector), FITU-R (Fitted ITU-R), offer values with an error percentage higher than 30% in the 2.4 GHz band in relation to those measured in field tests. As a substantial improvement, we have developed optimized propagation models, with an error estimate of less than 9% in the worst-case scenario for the later benefit of farmers, consumers and the economic chain in the production of tomatoes.

System Environment Propagation Modeling for a Wi-Fi-like Network Operating in TV White Space

2014 ◽  
Vol 68 (3) ◽  
Author(s):  
Hashim Elshafie ◽  
N. Fisal ◽  
M. Abbas ◽  
H. Mohamad ◽  
N. Ramli
Keyword(s):  
Broad Band ◽  
Path Loss ◽  
Additional Benefit ◽  
White Space ◽  
End User ◽  
Loss Model ◽  
Tv White Space ◽  
System Environment ◽  
Propagation Modeling ◽  
Variable Environments

In paper, the effect of different environment has been studied. For the next Wi-Fi generation at different frequencies 470 MHz, 790 MHz, 2.4 GHz and 5.8 GHz. since USA and UK open up unitized portions of UHF Band for unlicensed usesecondary use. The purpose and interest in using these TV white spaces (TVWS) for providing services to end user as broad-band services through Wi-Fi like connectivity. There is awareness that Wi-Fi operating in TVWS will increase coverage range, speeds, and more reliable connections than traditional Wi-Fi at 2.4 GHz or 5.8 GHz. The Log-distance path loss model simulated by Matlab in variable environments, for instant indoor urban, outdoor urban, outdoor suburban and outdoor rural. Different graphs are illustrated to view the effect of the environment and frequencies to path loss and power received within versus distances. A comparison between traditional Wi-Fi based systems working in the 2.4 GHz and 5.8 GHz and TVWS systems in 470 MHz and 790 MHz, and results show that the favorable propagation conditions characterizing the TVWS frequencies may lead to better coverage with the additional benefit of lower transmit power levels.

scholarly journals Indoor Propagation Model for TV White Space

2014 ◽  
Author(s):  
Wataru Yamada ◽  
Motoharu Sasaki ◽  
Takatoshi Sugiyama ◽  
Oliver Holland ◽  
Shuyu Ping ◽  
...  
Keyword(s):  
Propagation Model ◽  
Indoor Propagation ◽  
White Space ◽  
Tv White Space

Reducing Probabilistic Weather Forecasts to the Worst Case Scenario: Anchoring Effects

2008 ◽  
Author(s):  
Sonia Savelli ◽  
Susan Joslyn ◽  
Limor Nadav-Greenberg ◽  
Queena Chen
Keyword(s):  
Case Scenario ◽  
Worst Case ◽  
Weather Forecasts ◽  
Worst Case Scenario ◽  
Anchoring Effects

EXPEDITION TO MALI, 2020

2020 ◽  
pp. 12-28
Author(s):  
D. V. Vaniukova ◽  
◽  
P. A. Kutsenkov ◽  
Keyword(s):  
Mass Murder ◽  
The State ◽  
Case Scenario ◽  
Worst Case ◽  
Traditional Art ◽  
Peter The Great ◽  
State Museum ◽  
Bobo Dioulasso ◽  
Oriental Studies ◽  
The Village

The research expedition of the Institute of Oriental studies of the Russian Academy of Sciences has been working in Mali since 2015. Since 2017, it has been attended by employees of the State Museum of the East. The task of the expedition is to study the transformation of traditional Dogon culture in the context of globalization, as well as to collect ethnographic information (life, customs, features of the traditional social and political structure); to collect oral historical legends; to study the history, existence, and transformation of artistic tradition in the villages of the Dogon Country in modern conditions; collecting items of Ethnography and art to add to the collection of the African collection of the. Peter the Great Museum (Kunstkamera, Saint Petersburg) and the State Museum of Oriental Arts (Moscow). The plan of the expedition in January 2020 included additional items, namely, the study of the functioning of the antique market in Mali (the “path” of things from villages to cities, which is important for attributing works of traditional art). The geography of our research was significantly expanded to the regions of Sikasso and Koulikoro in Mali, as well as to the city of Bobo-Dioulasso and its surroundings in Burkina Faso, which is related to the study of migrations to the Bandiagara Highlands. In addition, the plan of the expedition included organization of a photo exhibition in the Museum of the village of Endé and some educational projects. Unfortunately, after the mass murder in March 2019 in the village of Ogossogou-Pel, where more than one hundred and seventy people were killed, events in the Dogon Country began to develop in the worst-case scenario: The incessant provocations after that revived the old feud between the Pel (Fulbe) pastoralists and the Dogon farmers. So far, this hostility and mutual distrust has not yet developed into a full-scale ethnic conflict, but, unfortunately, such a development now seems quite likely.

Risk-Based Robust Bidding Strategies for EVs’ Aggregators in Day-ahead Markets with Uncertainty

2020 ◽  
Author(s):  
Ahmed Abdelmoaty ◽  
Wessam Mesbah ◽  
Mohammad A. M. Abdel-Aal ◽  
Ali T. Alawami
Keyword(s):  
Robust Optimization ◽  
Electricity Market ◽  
Real Life ◽  
Optimization Approach ◽  
Case Scenario ◽  
Worst Case ◽  
Bidding Strategies ◽  
Wind Generators ◽  
Proposed Model ◽  
Optimal Bidding

In the recent electricity market framework, the profit of the generation companies depends on the decision of the operator on the schedule of its units, the energy price, and the optimal bidding strategies. Due to the expanded integration of uncertain renewable generators which is highly intermittent such as wind plants, the coordination with other facilities to mitigate the risks of imbalances is mandatory. Accordingly, coordination of wind generators with the evolutionary Electric Vehicles (EVs) is expected to boost the performance of the grid. In this paper, we propose a robust optimization approach for the coordination between the wind-thermal generators and the EVs in a virtual<br>power plant (VPP) environment. The objective of maximizing the profit of the VPP Operator (VPPO) is studied. The optimal bidding strategy of the VPPO in the day-ahead market under uncertainties of wind power, energy<br>prices, imbalance prices, and demand is obtained for the worst case scenario. A case study is conducted to assess the e?effectiveness of the proposed model in terms of the VPPO's profit. A comparison between the proposed model and the scenario-based optimization was introduced. Our results confirmed that, although the conservative behavior of the worst-case robust optimization model, it helps the decision maker from the fluctuations of the uncertain parameters involved in the production and bidding processes. In addition, robust optimization is a more tractable problem and does not suffer from<br>the high computation burden associated with scenario-based stochastic programming. This makes it more practical for real-life scenarios.<br>

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