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Intermediate and Radiofrequency Sources and Exposures in Everyday Environments
Published in Ben Greenebaum, Frank Barnes, Bioengineering and Biophysical Aspects of Electromagnetic Fields, 2018
Current mobile phone telephony operates with frequencies between 800 and 2,100 MHz although specialized systems used by professionals such as police, firemen, or ambulances, use lower frequencies around 400 MHz. Mobile telephony systems involve communication between hand-sets (uplink) with nearby base stations (downlink) which cover specific areas (cells), achieving the desired coverage. In recent years, the number of technologies has increased enormously, and several networks have been put in place, which make use of different frequency bands (Table 2.1). The “Groupe Spécial Mobile” or Global system for mobile communications (GSM) networks cover over 90% of the market. This includes the original 1G analogue network, plus the digital networks 2G and 3G (UMTS). The new 4G network is not part of the GSM standard. An important feature of mobile telecommunication systems is adaptive power control, which allows avoiding unnecessarily high power that would lead to interference and reduced capacity. However, for the purpose of exposure assessment it is assumed that the radiated power equals the maximum possible, although this is seldom used (ICNIRP, 1996). Base station transmitting antennas are formed of vertical arrays of collinear dipoles phased to give a narrow beamwidth (typically between 7 and 10 degrees). The antennas are mounted on buildings or on high towers. They are a source of whole-body exposure of people in their proximity. Exposure of the general public typically occurs in the far field zone, where the electric and magnetic fields vary inversely with distance (radiating far field) and there is commonly compliance with basic limits.
FPGA implementation of hardware architecture with AES encryptor using sub-pipelined S-box techniques for compact applications
Published in Automatika, 2020
C. Arul Murugan, P. Karthigaikumar, Sridevi Sathya Priya
An efficient scheme for both hardware and software implementation is AES encryption. While compared to software implementation, greater physical security is provided by hardware implementation with higher speed. The applications of wireless security systems, such as military communications and mobile telephony hardware implementation, are very useful in the speed of communication. In the last encryption or decryption process the mix column step and its inverse are not applied. During these steps using four polynomials each column of the state array will be processed. The columns are considered as polynomials over GF (2 8) and multiplied by modulo with a fixed polynomial . The multiplication between the polynomials , and modulo will result in the matrix Matrix can be written in polynomials The designed architecture of 128-bit AES Encryption process is executed on Virtex-4 XC4VLX200. This resulted in speed, area efficiency and lesser hardware requirements on an FPGA. The simulation waveform of substitution transformation and mix column transformation is shown in Figures 10 and 11, respectively. Also, the simulation waveform of 128-bit AES Encryption and Decryption is given in Figure 12 and 13, respectively. The power report of AES is shown in Figure 14 and hardware utilization report executed on Virtex-4 and Spartan 3 is given in Tables 6 and 7, respectively.
High-temperature impedance properties of Sr1-xCaxTiO3 ceramics for lead-free capacitor applications
Published in Phase Transitions, 2023
Amina Tachafine, Hicham Ait Laasri, Jean-Claude Carru, Didier Fasquelle
Currently, sensor networks, satellite transmission and telecommunication systems, mobile telephony and portable electronics in general are experiencing a considerable boom that is associated with a need for advanced electronic circuits [1]. These multiple developments are accompanied by a rapid and growing demand for frequency-tunable components and multifunctional devices that are increasingly efficient, miniature and consume less electrical energy [2].
Influence of user density distribution on the pairing probability in GSM cell with implemented VAMOS technology
Published in Automatika, 2018
Dragan Mitić, Aleksandar Lebl, Žarko Markov
The simulation programme for the system with the implemented VAMOS technique is developed on the basis of earlier implemented simulation programmes for different mobile telephony systems [8, 15–17]. Among these references, contribution [8] is the most important for the simulation in this paper, because system with non-uniform user distribution is considered in [8], as in this paper.