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The purpose of this chapter is to provide an overview and summary of the fundamental meaning and concepts of radio-frequency and wireless communication systems. It begins with a 2 summary of the history of wireless communications in general, from the first radio-frequency communication system to current cellular mobile radio systems. It then procee...
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Context 1
... radio waves will undergo reflection if the propagation medium undergoes abrupt changes in its physical properties. This is illustrated in Figure 5. The more abrupt the discontinuity, the more pronounced the reflection. ...
Context 2
... (see Figure 5) occurs at the boundary between two dielectrics, when the incident wave propagates into another medium at an angle. When radio waves propagate from a medium of one density to a medium of another density, the speed of the wave changes. ...
Context 3
... of radio waves occurs when the waves encounter some obstruction along their path and tend to propagate around the edges and corners and behind the obstruction. This is illustrated in Figure 5. The height or dimension of the obstruction has to be comparable to the wavelength of the transmission. ...
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Citations
... The information on the mean values of signals in telecommunications like cell phones, Internet protocol, computers, radios, printers, and all devices that use a frequency to communicate, i.e., wireless connectivity, is not sufficient to characterize the performance of communication systems; the variation in time, space and frequency, must also be taken into account [46], [47]. The dynamic behavior of the desired and interfering signals plays a decisive role in the analysis of system reliability and the choice of system parameters; in such a way, the signals must be considered as a random variable, and to model this variable, a probability density function needs it [48]. ...
With technological advances, companies are allowed to integrate digital data, physical supplies, and human resources, and all this integration capability can be done thanks to Industry 4.0. This concept, also called the fourth industrial revolution, refers to smart companies that work with intelligent cyber-physical systems. Industry 4.0enables automation, data interchange, and big data processing, among others. Then, the process decision-making, efficiency, and productivity improvement for companies will become faster and more accurate, thanks to real-time data processes and all supply chain integration allowed by Industry 4.0. However, the implementation of Industry 4.0 carries several challenges for companies to have success in the transformation of a normal industry into an Industry 4.0, like the necessity of adding new hardware, software, and other technologic devices. Because of this, the implementation and control of Industry 4.0 come with new issues to handle and new failure modes for both hardware and electronic devices. These problems can be faced using reliability engineering tools. Then the object of this research is the use of reliability engineering methodology stress-strength Weibull analysis, highlighting that the behavior of frequency emitted by electronics devices follows a Weibull distribution most of the time. Also, a stress-strength Weibull with a different shape parameter close solution is presented to increase the efficiency and productivity in Industry 4.0 electronic devices.
... Licence CC BY-NC-ND 3.0 Cet exemple de système de télécommunication montre l'important rôle des filtres passebande dans le fonctionnement des chaines d'émission et de réceptions pour la transmission des signaux en haute fréquences. De point de vue systèmes RF, les autres composants (comme l'antenne, et l'amplificateur de la chaine de réception) fonctionnant à la basse fréquence FI fixe [2]. ...
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... The RFI may also happen when an antenna of the transmitter on the ground is pointed at the wrong satellite in the orbit. Another unintentional RFI can be from interference between signals used in communication with the satellite and these used in different terrestrialnetworks systems.24 Article 15 of the Radio Regulation prohibits all kinds of interference from radio stations including carrying out unnecessary transmissions of unidentified, false, misleading or superfluous signals with exception of those provided under Article 19. 25 In contrast, due to the large extent use of satellite in miscellaneous activities including state security, the intentional RFI is more likely to take place. ...
The radio frequency spectrum is a limited natural resource which is very vital and strategic in the operation of telecomunications. Considering that the radio frequency spectrum is a limited natural resources, its management is regulated internatioanlly by the International Telecomunication Union (ITU), in which details are set out in the radio regulations (RR) as an integal part of the ITU Convention. The study is based on applicable legal regulations and is supported by literature studies. The result of the study indicate that the regulation of the radio frequency spectrum is based on radio regulation, international agreements within the ITU throught the World Radiocommunication Conference forum. The implications of regulating the use off the radio frequency spectrum always take into account the general public needs for the dynamics of the progress in telecomunications technology, of which implementation of its utilization rest on the principle of fairness and equity between regions and efficiency. Therefore, all policies made are directed at creating a market balance, ensuring fair competition between telecomunication operators as a potential to prevent market dominance, as well as protecting consumers.
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This study was aimed at analyzing the effect of temperature and relative humidity on downlink satellite communication systems over Warri, in Delta State, Nigeria. The data used in this study were temperature, relative humidity and radio signal strength (RSS) obtained from the Nigeria Meteorological Agency (NIMET) for the years 2018 and 2019 respectively, both from January to December. Davis Vantage Vue weather station was used to measure the temperature and relative humidity while Spectrum analyzer was used to measure RSS. Both instruments were set to function simultaneously. Results obtained for all the months shows that the level of radio signal strength under the influence of temperature is higher either RSS ≥ 65% compare to that of relative humidity either RSS ≤ 64% which also fluctuate the level of RSS on daily basis, throughout the years under review. It was realized that there is a variation in the refractive index of the medium through which the radiowaves are propagated, due to the variations in the temperature and relative humidity, these adversely affect the received signals strength over the downlink satellite communication systems. The results obtained from this study will serve as guide for link budget design for satellite communication operators within the study. Therefore, similar study of this kind is recommended in other locations experiencing severe weather conditions.
Wireless communications and networking technology have developed rapidly in the past few years. As Artificial Intelligence (AI) technique is utilized, the network becomes more self‐operational, self‐configurational, and self‐managed. Upcoming generations of wireless networks should be able to provide highly reliable and low‐latency communication. Integrating fundamental concepts of artificial intelligence (AI) and machine learning into the wireless systems and user devices can become a big achievement. Artificial intelligence can help manage network systems more efficiently and make them autonomous as well, while significantly enhancing the performance. The current advances in machine learning and wireless communication technologies are a big breakthrough for future networks, which are expected to be reliable and intelligent.
