Journal of Communication and Information Systems <p>The Journal of Communication and Information Systems (JCIS) features high-quality, peer-reviewed technical papers in several areas of communications and information systems. The JCIS is jointly sponsored by the Brazilian Telecommunications Society (SBrT) and the IEEE Communications Society (ComSoc). As from June 2020, Prof. Rausley Adriano Amaral de Souza from National Institute of Telecommunications (Inatel) and Prof. José Cândido Silveira Santos Filho from University of Campinas (UNICAMP) are the Editors-in-Chief of the JCIS.&nbsp;</p> <p>There are no article publication or submission charges. Previous editions of the JCIS can be accessed <a href="/index.php/JCIS/issue/archive" target="_blank" rel="noopener">here</a>.</p> <p>This is an open access journal which means that all content is freely available without charge to the user or his/her institution, permanently accessible online immediately upon assignment of the DOI. Users are allowed to read, download, copy, distribute, print, search, or link to the full texts of the articles, or use them for any other lawful purpose, without asking prior permission from the publisher or the author. This is in accordance with the BOAI definition of open access.</p> <p>ISSN: 1980-6604</p> Brazilian Telecommunications Society en-US Journal of Communication and Information Systems 1980-6604 <p><span>Authors who publish with this journal agree to the following terms:</span><br /><br /></p><ol type="a"><ol type="a"><li>Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a <a href="" target="_new">Creative Commons Attribution License</a> that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.</li></ol></ol><p> </p><ol type="a"><ol type="a"><li>Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.</li></ol></ol><p> </p><ol type="a"><ol type="a"><li>Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See <a href="" target="_new">The Effect of Open Access</a>).</li></ol></ol><p>___________</p> Empirical Path Loss Model in City-forest Environment for Mobile Communications <div class="page" title="Page 1"> <div class="layoutArea"> <div class="column"> <p>The feasible choice of a propagation model for a given wireless system depends on environment type among other factors. Thus, it is a crucial decision on radio network planning. This current proposal is a new methodology applied for LTE systems that includes: to find optimal parameters of a propagation model that minimizes RMS error and maximizes grey relation grade and mean absolute percentage error, (GRG- MAPE) in a city-forest environment through the use of meta- heuristic optimization such as Cuckoo Search (CS). The results, quantitatively analysed by RMS error and GRG-MAPE, shows a better accuracy of optimized model in comparison with the original version and even with SUI model.</p> </div> </div> </div> Andre Augusto Pacheco de Carvalho Iury Batalha Miercio Alcantara Bruno Castro Fabricio Barros Jasmine Araujo Gervasio Cavalcante ##submission.copyrightStatement## 2021-03-05 2021-03-05 36 1 70 74 10.14209/jcis.2021.7 Conversion of Scattering Parameters to Time-Domain for Imaging Applications: Rules and Examples <p>This article discusses the conversion of scattering parameters from an antenna input port to time domain for imaging applications. Frequency-domain measurements offer some advantages to time-domain methods, and the complex data encoded in the scattering matrix convey target geometric and material information which can be later used to reproduce the scene image illuminated by the antenna. Three different examples using the inverse discrete Fourier transform are discussed. Trade-offs in the data acquisition, bandwidth, sampling and topics related to the antennas used as probes are covered.</p> marcelo bender perotoni Claudio Jose Bordin Jr. Kenedy Marconi Geraldo dos Santos ##submission.copyrightStatement## 2021-03-02 2021-03-02 36 1 62 69 10.14209/jcis.2021.6 Performance Evaluation of MGfast Systems Over Coaxial Cables <p>A trend for the 5th generation fixed broadband access networks is to provide data rates as high as 10 Gbps to the subscribers. Since fiber-to-the-home (FTTH) connectivity is still expensive, the use of alternative architectures is attractive in some scenarios. In this context, the International Telecommunication Union (ITU) is standardizing the MGfast access technology to provide multi-gigabit transmission over copper media. This paper evaluates the performance of MGfast systems adopting RG-59, RG-6 and RG-11 coaxial cables as interface between the distribution point units (DPUs) and the customer premises equipment (CPE). The operation mode of MGfast is assumed to be synchronized time division duplexing (STDD) and a simple loading method for power allocation is employed. Simulation results show that, for loop lengths less than 100 m, data rate as high as 11 Gbps can be achieved using a transmission profile that goes up to 848 MHz. Assuming a profile that goes up to 1696 MHz, the data rates can be as high as 23 Gbps.</p> Marx Freitas Aline Ohashi Diogo Acatauassu João Weyl Costa Eduardo Medeiros Miguel Berg Igor Almeida André Cavalcante ##submission.copyrightStatement## 2021-03-01 2021-03-01 36 1 52 61 10.14209/jcis.2021.5 The Effective Secrecy Throughput for the Hybrid Wiretap Channel <p>This study discusses an augmented investigation of the hybrid wiretap channel, which represents a PLC system with its data security threatened by a malicious and passive wireless device at the physical layer level, by focusing on the evaluation and analysis of wiretap code rates. The wiretap code rates are obtained through effective secrecy throughput. In this sense, numerical analyses based on real data set composed of channel estimates and measured additive noises are provided. This data set was collected from a measurement campaign carried out in several Brazilian houses. From the perspective of the physical layer security, the attained results show wiretap code rates for overcoming the malicious presence of a passive wireless device located in the vicinity of broadband PLC systems under practical scenarios.</p> Ândrei Camponogara Moisés Vidal Ribeiro ##submission.copyrightStatement## 2021-02-23 2021-02-23 36 1 44 51 10.14209/jcis.2021.4 A Comparative Analysis of Undersampling Techniques for Network Intrusion Detection Systems Design <p>Intrusion Detection Systems (IDS) figure as one of the leading solutions adopted in the network security area to prevent intrusions and ensure data and services security. However, this issue requires IDS to be assertive and efficient processing time. Undersampling techniques allow classifiers to be evaluated from smaller subsets in a representative manner, aiming high assertive metrics in less processing time. There are several solutions in literature for IDS projects, but some criteria are not respected, such as the adoption of a replicable methodology. In this work, we selected three undersampling methodologies: random, Cluster centroids, and NearMiss in two novel unbalanced datasets (CIC2017 and CIC2018) for comparison between five classifiers using cross-validation and Wilcoxon statistical test. Our main contribution is a systematic and replicable methodology for using subsampling techniques to balance the data sets adopted in the IDS project. We choose three metrics for classifier's choice in an IDS design: accuracy, f1-measure, and processing time. The results indicate that the under-sampling by Cluster centroids presents the best performance when applied to distance-based classifiers. Moreover, under-sampling techniques influence the process of choosing the best classifier in the design of an IDS.</p> Bruno Riccelli Silva Ricardo Jardel Silveira Manuel Gonçalves da Silva Neto Paulo Cesar Cortez Danielo Gonçalves Gomes ##submission.copyrightStatement## 2021-02-18 2021-02-18 36 1 31 43 10.14209/jcis.2021.3 A Survey of LoRaWAN Simulation Tools in ns-3 <p>The Internet of Things (IoT) paradigm gains more importance each day, as the number and variety of connected devices grows. To answer the specific needs of IoT, many wireless network standards have been developed. An example is the LoRaWide Area Network (LoRaWAN), which has gained popularity thanks to the affordable costs of its devices and gateways, as well as wide range, low energy consumption and flexibility. Considering the challenges that exist with testing and researching on real LoRaWAN systems, the development of accurate network simulators is invaluable. Therefore, this work presents a survey of the available tools for simulating LoRa networks in ns-3 network simulator. We present how those simulators were implemented and their main features and limitations. We also showcase how those simulators are being used in the literature to evaluate the performance of LoRA networks. Finally, we compare the module so highlight what scenarios each of them is more suited for.</p> Jéssika C. da Silva Daniel de L. Flor Vicente Angelo de Sousa Junior Níbia Souza Bezerra Alvaro A. M. de Medeiros ##submission.copyrightStatement## 2021-02-06 2021-02-06 36 1 17 30 10.14209/jcis.2021.2 LoRa System for Monitoring and Facial Recognition <p>With the increasing tendency of incorporating technology into environments and activities in everyday life, new methods are being proposed to better integrate devices and mankind. Networks designed for monitoring areas through video and image systems are being implemented in several applications.<br>Recent studies have shown interest from both the academy and industry to integrate wireless surveillance networks with low-cost and long range transmission technologies, such as LoRa (Long Range). With the intention to explore this topic, this work presents the development of a system prototype for intelligent<br>monitoring as a basis to future implementation of low-cost LoRa-based Wireless Image Sensor Networks (WISN). The system developed consists of a processing unit, a data routing interface and multiple sensor nodes. Its operation is autonomous and initiated through the detection of human presence, by the sensor<br>node, capturing an image of the individuals present at each detection. The data is transmitted through LoRa devices to the central hub, where python-based methods of facial detection and recognition are employed. Several tests were performed to both adjust the system and to verify its efficiency. The results achieved<br>were satisfactory, indicating the viability of the proposed low-cost LoRa-based WISN.</p> Vitor J. C. Rodrigues Douglas F. Medeiros Fabrício B. S. Carvalho Waslon Terllizzie A. Lopes ##submission.copyrightStatement## 2021-01-08 2021-01-08 36 1 1 16 10.14209/jcis.2021.1 Propagation models for 5G signals in the 60 GHz band <p>Wireless data traffic is increasing due to the growing numbers of mobile phones and devices connected to the network. A large number of devices needs to be interconnected so it becomes necessary to increase the spectrum band and data traffic simultaneously to have the network working properly, those are some of goals of the 5G network. Frequencies in the range of 20 GHz until 300 GHz are in a spectrum band called millimeter waves band, also known by mmWave. This paper discusses the usage of 60 GHz band in the 5G networks. The 60 GHz band has the advantages like frequency reuse and short-distance connectivity.&nbsp; This paper also argues the problems that may arise from the choosing 60 GHz band. Wireless data traffic is increasing due to the growing numbers of mobile phones and devices connected to the network. A large number of devices needs to be interconnected so it becomes necessary to increase the spectrum band and data traffic simultaneously to have the network working properly, those are some of goals of the 5G network. Frequencies in the range of 20 GHz until 300 GHz are in a spectrum band called millimeter waves band, also known by mmWave. This paper discusses the usage of 60 GHz band in the 5G networks. The 60 GHz band has the advantages like frequency reuse and short-distance connectivity.&nbsp; This paper also argues the problems that may arise from the choosing 60 GHz band.</p> Gustavo Kreuzer Marengo Eduardo Saia Lima Gabriel Eduardo Silva Leite Arismar Cerqueira Sodré Junior Luciano Leonel Mendes ##submission.copyrightStatement## 2020-12-31 2020-12-31 36 1 357 369 10.14209/jcis.2020.36 Spectrum Efficient GFDM Based on Faster Than Nyquist Signaling <p>Future mobile communication system will provide high data rates for a miscellany of new applications. Spectrum efficiency is a key performance indicator that must be considerably improved for the beyond 5G networks. In this paper,&nbsp;a new approach to increase the waveform spectrum efficiency is investigated. This novel schemes combines the faster-thanNyquist signaling with generalized frequency division multiplexing, resulting in a scheme that can hold the main benefits of this innovative waveform with the high spectral efficiency gain. The scheme proposed in this paper abandons the orthogonality principle for the time-frequency grid, reducing the spacing between the subcarriers. The reduced subcarrier spacing does not affect the minimum distance among the transmitted sequences, if the Mazo’s limit is respected and the data can be recovered by a non-linear receiver without bit error penalties. In this paper, maximum likelihood receiver will be used for a proof of conception, showing that the bit error performance is equivalent to the one achieved by orthogonal systems. The system will be integrated with a forward error control scheme, showing that the proposed scheme can be fully integrated with modern error control codes, while improving the spectrum efficiency by 20%.</p> Mariana Baracat de Mello Luciano Leonel Mendes Tiago Cardoso Barbosa ##submission.copyrightStatement## 2020-12-28 2020-12-28 36 1 349 356 10.14209/jcis.2020.35 A Noise-Reduction Method With Coherence Enhancement for Binaural Hearing Aids <p>In this work, a variation of the multichannel Wiener filter (MWF) for noise reduction in binaural hearing aid applications is proposed. This method provides improved spatial preservation for acoustic scenarios comprised of one single-point target (speech) and one single-point interfering (noise) acoustic sources. It employs a regularization penalty term based on the inverse of the magnitude of the interaural coherence (IC), with the aim of enhancing the original azimuth perception of the interferent source. The proposed penalty term artificially intensifies the IC of the residual interference, increasing similarity in both ears. This is of special value for low-coherent reverberant acoustic signals, in which the reliability of the received binaural cues associated to the single-point interferent source was degraded by multiple acoustic reflections. Simulation results obtained with objective criteria show that, in addition of providing improved spatial preservation for the interferent source, the proposed approach may also provide higher noise reduction performance as compared to the conventional MWF approach. Further, it also yields an extended range for the target and interference spatial-preservation trade-off, as compared to a previously developed competing method. Psychoacoustic experiments with normal hearing volunteers corroborate theoretical and simulation findings.</p> Johnny Werner Marcio Holsbach Costa ##submission.copyrightStatement## 2020-12-21 2020-12-21 36 1 338 348 10.14209/jcis.2020.34