Special Issue "Modern Circuits and Systems Technologies on Communications 2020"

A special issue of Telecom (ISSN 2673-4001).

Deadline for manuscript submissions: closed (28 February 2021) | Viewed by 9542

Special Issue Editors

Dr. Sotirios K. Goudos
E-Mail Website
Guest Editor
[email protected], Department of Physics, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece
Interests: antenna design; microwave components design; wireless communications; evolutionary algorithms; machine learning
Special Issues, Collections and Topics in MDPI journals
Prof. Dr. George K. Karagiannidis
grade E-Mail Website
Guest Editor
Department of Electrical and Computer Engineering, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece
Interests: wireless communications; wireless power transfer and applications; optical wireless communications; communications for biomedical engineering; wireless security
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

The 9th International Conference on Modern Circuit and System Technologies on Electronics and Communications (MOCAST 2020) will take place in Bremen, Germany from September 7 to 9, 2020. The MOCAST technical program includes all aspects of communications and network technologies from antenna design, propagation modeling, wireless communications, and network systems and applications. This Special Issue aims at publishing extented versions of papers in the area of communications from the conference. Potential topics include but are not limited to the following:

  • Antenna design;
  • Propagation;
  • Communications systems;
  • Wireless communications;
  • Network systems.

Prof. Dr. Sotirios K. Goudos
Prof. Dr. George Karagiannidis
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Telecom is an international peer-reviewed open access quarterly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1000 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • antenna design
  • propagation
  • wireless communications
  • network systems

Published Papers (7 papers)

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Research

Article
High-Efficiency Triple-Band RF-to-DC Rectifier Primary Design for RF Energy-Harvesting Systems
Telecom 2021, 2(3), 271-284; https://doi.org/10.3390/telecom2030018 - 09 Aug 2021
Viewed by 1264
Abstract
Radio Frequency (RF) energy harvesting has been emerged as a potentially reliable method to replace the costly and difficult to maintain source of low-power wireless sensor networks. A plethora of dual-band rectifier designs has been proposed in the literature operating in various frequency [...] Read more.
Radio Frequency (RF) energy harvesting has been emerged as a potentially reliable method to replace the costly and difficult to maintain source of low-power wireless sensor networks. A plethora of dual-band rectifier designs has been proposed in the literature operating in various frequency bands. In this paper, a triple-band RF-to-DC rectifier that operates in the frequency bands of LoRaWAN, GSM-900, and WiFi 2.4 GHz is presented. The system is composed of an impedance-matching circuit, an RF-to-DC rectifier, that converts the ambient RF energy into DC voltage able to feed low-power devices, and an output load. The proposed system resonates at three different frequencies of 866 MHz, 948 MHz and 2423 MHz, which fall within the aforementioned frequency bands of interest. The feasible solution of the proposed system was based on a dual-band rectifier operating in the frequency bands of LoRaWAN and GSM-900. A series of shunt stubs was utilized in the initial design to form the feasible solution of the proposed system. The proposed triple-band rectifier was optimized using a powerful optimization algorithm, i.e., the genetic algorithm. The overall system exhibited improved characteristics compared to the initial design in terms of its resonance. Numerical results demonstrated that the overall system exhibited an efficiency of 81% with 3.23 V of the output voltage, for an input power of 0 dBm and a load of 13 kOhm. Full article
(This article belongs to the Special Issue Modern Circuits and Systems Technologies on Communications 2020)
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Article
Error Performance Estimation of Modulated Retroreflective Transdermal Optical Wireless Links with Diversity under Generalized Pointing Errors
Telecom 2021, 2(2), 167-180; https://doi.org/10.3390/telecom2020011 - 01 Apr 2021
Cited by 1 | Viewed by 1513
Abstract
Recent developments in both optical wireless communication (OWC) systems and implanted medical devices (IMDs) have introduced transdermal optical wireless (TOW) technology as a viable candidate for extremely high-speed in-body to out-of-body wireless data transmissions, which are growing in demand for many vital biomedical [...] Read more.
Recent developments in both optical wireless communication (OWC) systems and implanted medical devices (IMDs) have introduced transdermal optical wireless (TOW) technology as a viable candidate for extremely high-speed in-body to out-of-body wireless data transmissions, which are growing in demand for many vital biomedical applications, including telemetry with medical implants, health monitoring, neural recording and prostheses. Nevertheless, this emerging communication modality is primarily hindered by skin-induced attenuation of the propagating signal bit carrier along with its stochastic misalignment-induced fading. Thus, by considering a typical modulated retroreflective (MRR) TOW system with spatial diversity and optimal combining (OC) for signal reception in this work, we focus, for the first time in the MRR TOW literature, on the stochastic nature of generalized pointing errors with non-zero boresight (NZB). Specifically, under these circumstances, novel analytical mathematical expressions were derived for the total average bit error rate (BER) of various system configurations. Their results revealed significant outage performance enhancements when spatial diversity was utilized. Moreover, taking into consideration the total transdermal pathloss along with the effects of stochastic NZB pointing errors, the critical average signal-to-noise ratio (SNR) metric was evaluated for typical power spectral-density values. Full article
(This article belongs to the Special Issue Modern Circuits and Systems Technologies on Communications 2020)
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Article
Experimental Model Development for the Attenuation Coefficient Estimation of Terrestrial Optical Wireless Links over the Sea
Telecom 2021, 2(1), 93-107; https://doi.org/10.3390/telecom2010007 - 01 Mar 2021
Cited by 2 | Viewed by 1258
Abstract
Free space optical (FSO) systems have become a reliable solution for modern communications networks, due to the high performance, availability, reliability and security they can provide. However, their characteristics depend strongly on the conditions of the atmosphere, which is the propagation path of [...] Read more.
Free space optical (FSO) systems have become a reliable solution for modern communications networks, due to the high performance, availability, reliability and security they can provide. However, their characteristics depend strongly on the conditions of the atmosphere, which is the propagation path of the optical beam. In this work, this dependence is experimentally investigated through a terrestrial horizontal FSO link, which was installed a few meters above the sea. Thus, the procedure presented hereis an accurate empirical model for the estimation of the attenuation coefficient for an optical wireless link, as a function of the atmospheric temperature, the relative humidity, and the wind speed. Its accuracy is verified by comparing the estimated outcomes—obtained from the empirical model—versus the measured—experimental—ones. Such accurate empirical models can be used for designing high performance and reliability FSO links, as parts of the upcoming 5G/5G+ networks, for areas where the behavior of the atmospheric conditions and parameters are known. Full article
(This article belongs to the Special Issue Modern Circuits and Systems Technologies on Communications 2020)
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Article
Probabilistic Retry and Threshold Multirate Loss Models for Impatient Calls
Telecom 2021, 2(1), 28-41; https://doi.org/10.3390/telecom2010003 - 28 Jan 2021
Viewed by 1088
Abstract
In this paper, a link of fixed capacity is considered that services calls from different service-classes. Calls arrive in the link according to a Poisson process, have an initial (peak) bandwidth requirement while their service time is exponentially distributed. We model this system [...] Read more.
In this paper, a link of fixed capacity is considered that services calls from different service-classes. Calls arrive in the link according to a Poisson process, have an initial (peak) bandwidth requirement while their service time is exponentially distributed. We model this system as a multirate loss system and analyze two different multirate loss models. In the first model, named probabilistic retry loss model, if there is no available link bandwidth, a new call is blocked but retries with a lower bandwidth requirement and increased service time. To allow for the fact that a blocked call may be impatient, we assume that it retries with a probability. In the second model, named probabilistic threshold loss model, a call may reduce its bandwidth requirement (before blocking occurs) based on the occupied link bandwidth. To determine call blocking probabilities in both multirate loss models, we show that approximate but recursive formulas do exist that provide quite satisfactory results compared to simulation. Full article
(This article belongs to the Special Issue Modern Circuits and Systems Technologies on Communications 2020)
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Article
A Novel Chaotic System with a Line Equilibrium: Analysis and Its Applications to Secure Communication and Random Bit Generation
Telecom 2020, 1(3), 283-296; https://doi.org/10.3390/telecom1030019 - 17 Dec 2020
Cited by 2 | Viewed by 1364
Abstract
In this study, a novel two-parameter, three-dimensional chaotic system is constructed. The system has no linear terms and its equilibrium is a line, so it is a system with hidden attractors. The system is first studied by computation of its bifurcation diagrams and [...] Read more.
In this study, a novel two-parameter, three-dimensional chaotic system is constructed. The system has no linear terms and its equilibrium is a line, so it is a system with hidden attractors. The system is first studied by computation of its bifurcation diagrams and diagram of Lyapunov exponents. Then, the system is applied to two encryption related problems. First, the problem of secure communications is considered, using the symmetric chaos shift keying modulation method. Here, the states of the chaotic system are combined with a binary information signal in order to mask it, safely transmit it through a communication channel, and successfully reconstruct the information at the receiver end. In the second problem, the states of the system are utilized to design a simple rule to generate a bit sequence that possesses random properties, and is thus suitable for encryption related applications. For both applications, simulations are performed through Matlab to verify the soundness of the designs. Full article
(This article belongs to the Special Issue Modern Circuits and Systems Technologies on Communications 2020)
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Article
Improved Networks Routing Using an Arrow-Based Description
Telecom 2020, 1(3), 150-160; https://doi.org/10.3390/telecom1030011 - 28 Sep 2020
Cited by 2 | Viewed by 1040
Abstract
In this paper, an improved routing algorithm suitable for planar networks—static Zigbee and mesh networks included—is shown. The algorithm is based on the cycle description of the graph, and on a new graph model based on arrow description, which is outlined. We show [...] Read more.
In this paper, an improved routing algorithm suitable for planar networks—static Zigbee and mesh networks included—is shown. The algorithm is based on the cycle description of the graph, and on a new graph model based on arrow description, which is outlined. We show that the newly developed model allows for a faster algorithm for finding a direct and a return path in the network. The newly developed model allows further interpretations of the relationships in any simple planar graphs. Examples showing the implementation of the newly developed model are presented too. Full article
(This article belongs to the Special Issue Modern Circuits and Systems Technologies on Communications 2020)
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Article
Differential Evolution in Waveform Design for Wireless Power Transfer
Telecom 2020, 1(2), 96-113; https://doi.org/10.3390/telecom1020008 - 04 Aug 2020
Cited by 1 | Viewed by 1275
Abstract
The technique of transmitting multi-tone signals in a radiative Wireless Power Transfer (WPT) system can significantly increase its end-to-end power efficiency. The optimization problem in this system is to tune the transmission according to the receiver rectenna’s nonlinear behavior and the Channel State [...] Read more.
The technique of transmitting multi-tone signals in a radiative Wireless Power Transfer (WPT) system can significantly increase its end-to-end power efficiency. The optimization problem in this system is to tune the transmission according to the receiver rectenna’s nonlinear behavior and the Channel State Information (CSI). This is a non-convex problem that has been previously addressed by Sequential Convex Programming (SCP) algorithms. Nonetheless, SCP algorithms do not always attain globally optimal solutions. To this end, in this paper, we evaluate a set of Evolutionary Algorithms (EAs) with several characteristics. The performance of the optimized multi-tone transmission signals in a WPT system is assessed by means of numerical simulations, utilizing a simplified Single Input Single Output (SISO) model. From the model evaluation, we can deduce that EAs can be successfully applied to the waveform design optimization problem. Moreover, from the presented results, we can derive that EAs can obtain the optimal solutions in the tested cases. Full article
(This article belongs to the Special Issue Modern Circuits and Systems Technologies on Communications 2020)
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