Next Issue
Volume 2, June
Previous Issue
Volume 1, December

Telecom, Volume 2, Issue 1 (March 2021) – 9 articles

Cover Story (view full-size image): FSO links are part of modern ultra-fast networks, due to the high reliability, performance and security they can provide. However, the atmospheric conditions affect their characteristics and this influence is investigated experimentally through a terrestrial horizontal FSO link that is installed a few meters above the sea. An accurate empirical model for the attenuation coefficient estimation of the optical wireless links, as function of the atmospheric temperature, relative humidity and wind speed, is developed. Such models can be used for the designing of FSO links as parts of the upcoming 5G/5G+/6G networks, for areas with known atmospheric conditions behaviour. View this paper
  • Issues are regarded as officially published after their release is announced to the table of contents alert mailing list.
  • You may sign up for e-mail alerts to receive table of contents of newly released issues.
  • PDF is the official format for papers published in both, html and pdf forms. To view the papers in pdf format, click on the "PDF Full-text" link, and use the free Adobe Readerexternal link to open them.
Order results
Result details
Select all
Export citation of selected articles as:
Article
A Conditional Generative Adversarial Network Based Approach for Network Slicing in Heterogeneous Vehicular Networks
Telecom 2021, 2(1), 141-154; https://0-doi-org.brum.beds.ac.uk/10.3390/telecom2010009 - 18 Mar 2021
Viewed by 757
Abstract
Heterogeneous Vehicular Network (HetVNET) is a highly dynamic type of network that changes very quickly. Regarding this feature of HetVNETs and the emerging notion of network slicing in 5G technology, we propose a hybrid intelligent Software-Defined Network (SDN) and Network Functions Virtualization (NFV) [...] Read more.
Heterogeneous Vehicular Network (HetVNET) is a highly dynamic type of network that changes very quickly. Regarding this feature of HetVNETs and the emerging notion of network slicing in 5G technology, we propose a hybrid intelligent Software-Defined Network (SDN) and Network Functions Virtualization (NFV) based architecture. In this paper, we apply Conditional Generative Adversarial Network (CGAN) to augment the information of successful network scenarios that are related to network congestion and dynamicity. The results show that the proposed CGAN can be trained in order to generate valuable data. The generated data are similar to the real data and they can be used in blueprints of HetVNET slices. Full article
Show Figures

Figure 1

Review
Blockchain-Based Solutions for UAV-Assisted Connected Vehicle Networks in Smart Cities: A Review, Open Issues, and Future Perspectives
Telecom 2021, 2(1), 108-140; https://0-doi-org.brum.beds.ac.uk/10.3390/telecom2010008 - 12 Mar 2021
Viewed by 961
Abstract
It had been predicted that by 2020, nearly 26 billion devices would be connected to the Internet, with a big percentage being vehicles. The Internet of Vehicles (IoVa) is a concept that refers to the connection and cooperation of smart vehicles and devices [...] Read more.
It had been predicted that by 2020, nearly 26 billion devices would be connected to the Internet, with a big percentage being vehicles. The Internet of Vehicles (IoVa) is a concept that refers to the connection and cooperation of smart vehicles and devices in a network through the generation, transmission, and processing of data that aims at improving traffic congestion, travel time, and comfort, all the while reducing pollution and accidents. However, this transmission of sensitive data (e.g., location) needs to occur with defined security properties to safeguard vehicles and their drivers since attackers could use this data. Blockchain is a fairly recent technology that guarantees trust between nodes through cryptography mechanisms and consensus protocols in distributed, untrustful environments, like IoV networks. Much research has been done in implementing the former in the latter to impressive results, as Blockchain can cover and offer solutions to many IoV problems. However, these implementations have to deal with the challenge of IoV node’s resource constraints since they do not suffice for the computational and energy requirements of traditional Blockchain systems, which is one of the biggest limitations of Blockchain implementations in IoV. Finally, these two technologies can be used to build the foundations for smart cities, enabling new application models and better results for end-users. Full article
Show Figures

Figure 1

Article
Experimental Model Development for the Attenuation Coefficient Estimation of Terrestrial Optical Wireless Links over the Sea
Telecom 2021, 2(1), 93-107; https://0-doi-org.brum.beds.ac.uk/10.3390/telecom2010007 - 01 Mar 2021
Cited by 1 | Viewed by 766
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)
Show Figures

Figure 1

Review
A Literature Review on Caching Transient Contents in Vehicular Named Data Networking
Telecom 2021, 2(1), 75-92; https://0-doi-org.brum.beds.ac.uk/10.3390/telecom2010006 - 09 Feb 2021
Viewed by 755
Abstract
Vehicular Named Data Networking (VNDN) is a revolutionary information-centric architecture specifically conceived for vehicular networks and characterized by name-based forwarding and in-network caching. So far, a variety of caching schemes have been proposed for VNDN that work in presence of static Data packets, [...] Read more.
Vehicular Named Data Networking (VNDN) is a revolutionary information-centric architecture specifically conceived for vehicular networks and characterized by name-based forwarding and in-network caching. So far, a variety of caching schemes have been proposed for VNDN that work in presence of static Data packets, like traditional Internet contents. However, with the advent of Internet of Things (IoT) and Internet of Vehicles (IoV) applications, large sets of vehicular contents are expected to be transient, i.e., they are characterized by a limited lifetime and become invalid after the latter expires. This is the case of information related to road traffic or parking lot availability, which can change after a few minutes—or even after a few seconds—it has been generated at the source. The transiency of contents may highly influence the network performance, including the gain of in-network caching. Therefore, in this paper, we consider the dissemination of transient contents in vehicular networks and its effects on VNDN caching. By providing a detailed review of related work, we identify the main challenges and objectives when caching transient contents, e.g., to avoid cache inconsistency, to minimize the Age of Information (AoI) and the retrieval latency, and the main strategies to fulfill them. We scan the existing caching and replacement policies specifically designed for transient contents in VNDN and, finally, we outline interesting research perspectives. Full article
(This article belongs to the Special Issue Recent Advances in Smart and Pervasive Internet of Things)
Show Figures

Figure 1

Article
Towards Climate Smart Farming—A Reference Architecture for Integrated Farming Systems
Telecom 2021, 2(1), 52-74; https://doi.org/10.3390/telecom2010005 - 09 Feb 2021
Viewed by 983
Abstract
Climate change is emerging as a major threat to farming, food security and the livelihoods of millions of people across the world. Agriculture is strongly affected by climate change due to increasing temperatures, water shortage, heavy rainfall and variations in the frequency and [...] Read more.
Climate change is emerging as a major threat to farming, food security and the livelihoods of millions of people across the world. Agriculture is strongly affected by climate change due to increasing temperatures, water shortage, heavy rainfall and variations in the frequency and intensity of excessive climatic events such as floods and droughts. Farmers need to adapt to climate change by developing advanced and sophisticated farming systems instead of simply farming at lower intensity and occupying more land. Integrated agricultural systems constitute a promising solution, as they can lower reliance on external inputs, enhance nutrient cycling and increase natural resource use efficiency. In this context, the concept of Climate-Smart Agriculture (CSA) emerged as a promising solution to secure the resources for the growing world population under climate change conditions. This work proposes a CSA architecture for fostering and supporting integrated agricultural systems, such as Mixed Farming Systems (MFS), by facilitating the design, the deployment and the management of crop–livestock-=forestry combinations towards sustainable, efficient and climate resilient agricultural systems. Propelled by cutting-edge technology solutions in data collection and processing, along with fully autonomous monitoring systems, e.g., smart sensors and unmanned aerial vehicles (UAVs), the proposed architecture called MiFarm-CSA, aims to foster core interactions among animals, forests and crops, while mitigating the high complexity of these interactions, through a novel conceptual framework. Full article
(This article belongs to the Special Issue Machine Learning Applications in Smart Agriculture)
Show Figures

Figure 1

Article
Design and Analysis of Slotted Waveguide Antenna Radiating in a “Plasma-Shaped” Cavity of an ECR Ion Source
Telecom 2021, 2(1), 42-51; https://0-doi-org.brum.beds.ac.uk/10.3390/telecom2010004 - 08 Feb 2021
Viewed by 708
Abstract
The design of a microwave antenna sustaining a high-energy-content plasma in Electron Cyclotron Resonance Ion Sources (ECRISs) is, under many aspects, similar to the design of a conventional antenna but presenting also peculiarities because of the antenna lying in a cavity filled by [...] Read more.
The design of a microwave antenna sustaining a high-energy-content plasma in Electron Cyclotron Resonance Ion Sources (ECRISs) is, under many aspects, similar to the design of a conventional antenna but presenting also peculiarities because of the antenna lying in a cavity filled by an anisotropic plasma. The plasma chamber and microwave injection system design plays a critical role in the development of future ECRISs. In this paper, we present the numerical study of an unconventionally shaped plasma cavity, in which its geometry is inspired by the typical star-shaped ECR plasma, determined by the electrons trajectories as they move under the influence of the plasma-confining magnetic field. The cavity has been designed by using CST Studio Suite with the aim to maximize the on-axis electric field, thus increasing the wave-to-plasma absorption. As a second step, an innovative microwave injection system based on side-coupled slotted waveguides is presented. This new launching scheme allows an uniform power distribution inside the plasma cavity which could lead to an increase of ion source performances in terms of charge states and extracted currents when compared to the conventional axial microwave launch scheme. Finally, the use of both the “plasma-shaped” cavity and the microwave side coupled scheme could make the overall setup more compact. Full article
Show Figures

Figure 1

Article
Probabilistic Retry and Threshold Multirate Loss Models for Impatient Calls
Telecom 2021, 2(1), 28-41; https://0-doi-org.brum.beds.ac.uk/10.3390/telecom2010003 - 28 Jan 2021
Viewed by 679
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)
Show Figures

Figure 1

Editorial
Acknowledgment to Reviewers of Telecom in 2020
Telecom 2021, 2(1), 27; https://0-doi-org.brum.beds.ac.uk/10.3390/telecom2010002 - 16 Jan 2021
Viewed by 623
Abstract
Peer review is the driving force of journal development, and reviewers are gatekeepers who ensure that Telecom maintains its standards for the high quality of its published papers [...] Full article
Article
V2X Communication over Cellular Networks: Capabilities and Challenges
Telecom 2021, 2(1), 1-26; https://0-doi-org.brum.beds.ac.uk/10.3390/telecom2010001 - 13 Jan 2021
Cited by 1 | Viewed by 1371
Abstract
Vehicular communications is expected to be one of the key applications for cellular networks during the following decades. Key international organizations have already described in detail a number of related use cases, along with their requirements. This article provides a comprehensive analysis of [...] Read more.
Vehicular communications is expected to be one of the key applications for cellular networks during the following decades. Key international organizations have already described in detail a number of related use cases, along with their requirements. This article provides a comprehensive analysis of these use cases and a harmonized view of the requirements for the latest and most advanced autonomous driving applications. It also investigates the extent of support that 4G and 5G networks can offer to these use cases in terms of delay and spectrum needs. The paper identifies open issues and discusses trends and potential solutions. Full article
(This article belongs to the Special Issue Vehicular Communications)
Show Figures

Figure 1

Previous Issue
Next Issue
Back to TopTop