Polymer-based materials face increasing limitations imposed by the U.S.A. and European legislation due to their environmental impact, namely carbon footprint and recycling capabilities containing polyfluoroalkyl (PFA) substances. Radome antennas often use these materials due to their electrical and mechanical properties and, therefore, there is a search for alternative dielectrics. Here, we evaluate the performance of cork + nitrile rubber and cork + chloroprene rubber composites to be used in radomes at E-band for 5G backhaul communications. Both materials present a dielectric constant of around 1.6 and a loss tangent of 5x10 -2 at 50 GHz. We fabricated a 1-foot parabolic reflector antenna which we covered with a cork-rubber radome. We measured the radiation pattern and isotropic gain across the 71–86 GHz frequency band, showing overall correct results, and indicating that the cross-polarization slightly deteriorates with the use of cor k+rubber and the gain drops by around 1 dB, when compared to an ABS radome used by the majority of telecom equipment manufacturers.

Recent advances in wireless communication technologies are having a great impact on people’s life, especially in the field of healthcare industry that provides a remote monitoring enabling medical staff to follow up the patient and diagnose his disease. LoRa wireless technology is becoming one of the most energetic effective solutions for Wireless Body Area Networks (WBANs) communications. In this work, we propose a LoRa-based low power healthcare WBAN platform called HeaLoRa for an adaptive patient monitoring process. Physicians can remotely monitor patient’s temperature, oxygen saturation level, blood pressure and heart rate to prevent any abnormality. Moreover, data acquisition and transmission are controlled based on a power consumption optimization strategy aiming to reduce redundant data. Based on the Early Warning Score (EWS), the system configuration is dynamically adapted, using a Fuzzy logic controller that makes the decision about the system sleep mode duration and the sent data rate. Furthermore, an analytical model of the energy consumption for acknowledged LoRa transmission is presented in this paper. The graphical abstract of the paper illustrates a medical application of a wireless body area network system where LoRa technology is used to transmit the data to a gateway then the data is transmitted to the doctor using IP based technology. By comparing with a reference system, the simulation results indicate that our system consumes 3 to 10 times less of energy depending on the studied scenario.

Nowadays, keeping a strong and good health is one of the main concern of the general public or governments. The Internet of Things (IoT) has been emerged as an efficient solution to build smart healthcare systems deployed either at hospitals or in-home. Such networks rely on biomedical sensors which are used in electronics-based medical equipment to remotely collect vital signs of patients (pressure, temperature, hart rate, oxygen saturation etc.). Generally, these biosensors are implemented on or inside the patient's body and take three types of record data such as numerical, images and videos. However, the big data collected by various biomedical sensors along with the need of emergency detection, the limited sensor energies, and the prediction of the progress of patient situation are the major challenges for health-based IoT applications. In order to overcome these challenges, we propose, in this paper, an efficient sensor-based data analytics for real-time patient monitoring and assessment to help both hospital and medical staff. The proposed mechanism consists in three phases: Emergency detection, adapting sensing frequency and real time prediction of patient situation. Through simulations on real health data, we show the effectiveness of our mechanism compared to other exiting techniques.

A low-cost dual linearly polarized transmitarray antenna (TA) is presented for 5G and beyond networks at D-band. This TA is made of 40 × 40 unit-cells (UCs) and is illuminated by a stepped feed horn with a F/D ratio equal to 0.75. The flat lens panel is based on UCs with six different phase states at the center frequency of 150 GHz (thus leading in average to a 2 bit phase quantization and 0.7 dB insertion loss from 130 to 175 GHz). Each UC is made of only three metal layers and does not include any via connection to guarantee performance robustness with respect to fabrication dispersions. The measured 1 dB and 3 dB TA gain bandwidths equal 16.8% and 19.8%, respectively, with a peak gain of 32 dBi, corresponding to an aperture efficiency of 32% at 150 GHz. The measured sidelobe and cross-polarization levels in E- and H-planes remain below $-$21 and $-$37 dB, respectively. An excellent agreement between measured and simulated radiation patterns was observed.

A compact and conformal cylindrical antenna for IoT sensor applications is presented. Plastronics development using Laser Direct Structuring (LDS) process is carried on to optimize the space occupied by the antenna. Specific LDS-compatible polycarbonate (PC) thermoplastic is used as a substrate. The dipole antenna stands on the outer surface of a 17 mm high cylinder with a diameter of 48 mm. The antenna operates in the European ISM band (868 MHz), which implies a very low profile length dimension of (0.14 λ) 2 . The cylindrical holder is mounted in an industrial light fixture in order to be connected to a compact sensor board. Good agreement between simulations and measurements is found with a dipole-like radiation pattern and a maximum of 1.32 dBi measured gain. The 22 MHz bandwidth (S11 <; -10 dB) satisfies the European ISM band IoT protocols LoRa.

In this paper, a battery-powered Internet of Things assisting Cognitive Radio (CR-IoT) network is considered. In CR-IoT network, a set of IoT End Nodes (ENs) are assumed to cooperatively sense the channel. Each EN performs a Spectrum Sensing (SS) and reports its decision to a Fusion Center in order to reach the decision on the PU status. Such monitoring of PU comes at the cost of additional energy resources consumed by the EN to perform SS and reporting, and raises the need to set a suitable protocol to manage the data exchange. The extra operations may exhaust the energy of the EN battery, especially when Low Power Wide Area Networks (LPWAN) technology is used. In our manuscript, an Eligibility Score-based (ESco) Strategy is defined to reflect the eligibility of an EN to make a reliable SS taking into consideration its battery level. Our strategy is adapted to LoRaWAN Class-B protocol in order to handle real world scenarios. Necessary modifications are introduced to the existing protocol in order to support the synchronization between the ENs and the Application Server, (at which the SS need is identified), and the on-demand nature of the SS requests. To evaluate our strategy, LoRa sensors' parameters are considered in our simulations. The numerical results highlight the efficiency of the proposed strategy by showing the extension of the ENs' lifetime compared to classical strategies.

Interest and need for Wireless Body Area Networks (WBANs) have significantly increased recently. WBAN consists of miniaturized sensors designed to collect and transmit data through wireless network, enabling medical specialists to monitor patients during their normal daily life and providing real time opinions for medical diagnosis. Many wireless technologies have proved themselves in WBAN applications, while others are still under investigations. The choice of the technology to adopt may depend on the disease to monitor and the performance requirements, i.e. reliability, latency and data rate. In addition, the suitable sensor is essential when seeking to extract the data related to a medical measure. This paper aims at surveying the wireless technologies used in WBAN systems. In addition to a detailed survey on the existing technologies, the use of the emerging Low Power Wide Area Network (LPWAN) technologies, and the future 5G, B5G and 6G is investigated, where the suitability of these technologies to WBAN applications is studied from several perspectives. Furthermore, medical applications of WBAN are discussed by presenting their methodologies, the adopted wireless technologies and the used sensors. Given that each medical application requires the appropriate sensor to extract the data, we highlight a wide range of the sensors used in the market for medical systems. Recent and future challenges in WBAN systems are given related to the power consumption, the emergence of the Internet of Things (IoT) technologies in WBAN and others.

A 5 GHz WiFi stacked patch antenna array designed to connect bus shelters with high speed broadband is presented. A 45°/−45° orthogonal polarized 2x4 patch array stacked by 8 parasitic patches provides a 20% bandwidth (4.8 - 5.9 GHz), ensuring MIMO configuration with a gain of 7.8 dBi. Attention has been paid to the thickness of the antenna to ensure its discretion and its integration into the structure.

This paper presents the design, simulation and prototyping of a 2-bit dual linearly-polarized transmitarray antenna (TA) for 5G millimeter-wave point-to-point backhauling radio links at D-band (130 - 174.8 GHz). The flat lens consists of a square array with 1600 unit cells arranged on a 40×40 element regular grid. This array is based on a printed circuit board structure with only three metal layers and no via connection in order to minimize the insertion loss, the fabrication complexity and the overall cost of the system. The full-array has been optimized using array theory; these results are compared to full-wave simulations performed with Ansys HFSS. The 1-dB and 3-dB gain bandwidth equal 11.9% and 19.7% respectively, with a peak gain of 34.1 dBi and aperture efficiency of 51% at the center frequency. The unit cell configuration is fully symmetric to operate in dual polarization operation.

A compact and flexible dual-band antenna for near-body Internet of things (IoT) applications is presented. Modified Inverted F-antenna (IFA) structure is employed as to allow dual-band operation. Two thin films of Polycarbonate (PC) and Polyurethane (PU) are used in order to provide flexibility to the structure. The antenna covers incoming lower 5G (n18) and 915-MHz industrial, scientific and medical (ISM) bands and exhibits a maximum gain of -8.78 dBi. Moreover, antenna matching is insensitive to near body influence.

La caracterisation radio frequence large bande de deux thermoplastiques activables par structuration laser directe (LDS), le Xantar 3710 et le Zeonex RS-420, est presentee dans cette communication. Cette caracterisation est basee sur deux methodes. Une premiere technique s'appuie sur une structure resonante, ici un anneau couple sur ses entree et sortie a des lignes de transmission microruban. C'est une technique precise aux frequences de resonance de l'anneau. La seconde technique est une methode large bande. Elle utilise des lignes de transmission coplanaires blindees. Les parametres dielectriques de ces materiaux ont ete extraits jusqu’a 8,5 GHz. Les resultats de mesure confirment la pertinence des methodes de caracterisation hyperfrequences et l’interet de ces materiaux pour la realisation d’antennes moulees.

LoRa is a popular Low Power Wide Area Network (LPWAN) standard designed for the Internet of Things (IoT). The MAC layer protocol of LoRa is LoRaWAN. It still needs some improvements regarding the measured Quality of Service (QoS) i.e. rejected packet rate and the Packet Error Rate (PER). In this paper, we propose a LoRa+ as a new mechanism to overcome the shortcomings of LoRaWAN. Currently, at the end of each uplink operation, a standard LoRaWAN-based end device opens two time slots (RX1 and RX2) to receive from the gateway the channel parameters: the spreading factor and the operating frequency. These parameters have to be taken into account in the next uplink that sometimes happens few hours after (highly application dependent). During this interval, the channel conditions may change adversely impacting the performance. In our work, we propose to modify LoRaWAN MAC Layer for both Class A and Class B to address this issue. Instead of waiting the end of the uplink operation, the time slot dedicated to receive the channel parameters is shifted so that these parameters are sent just before the transmission slot. We show by simulations on Matlab that our modification reduces significantly the rejected packet rate and PER by up to 20% compared to LoRaWAN for small and medium size cities when the number of EDs is usually less than 500. Consequently, the number of gateway required in the network is also reduced, leading to the reduction of the network infrastructure costs.

Nowadays, the increasing number of patients accompanied with the emergence of new symptoms and diseases makes heath monitoring and assessment a complicated task for medical staff and hospitals. Indeed, the processing of big and heterogeneous data collected by biomedical sensors along with the need of patients’ classification and disease diagnosis become major challenges for several health-based sensing applications. Thus, the combination between remote sensing devices and the big data technologies have been proven as an efficient and low cost solution for healthcare applications. In this paper, we propose a robust big data analytics platform for real time patient monitoring and decision making to help both hospital and medical staff. The proposed platform relies on big data technologies and data analysis techniques and consists of four layers: real time patient monitoring, real time decision and data storage, patient classification and disease diagnosis, and data retrieval and visualization. To evaluate the performance of our platform, we implemented our platform based on the Hadoop ecosystem and we applied the proposed algorithms over real health data. The obtained results show the effectiveness of our platform in terms of efficiently performing patient classification and disease diagnosis in healthcare applications.

This letter presents a transmitarray antenna ( TA) in the 27.5-29.5 GHz frequency band. The proposed TA is optically transparent and offers the possibility of steering the beam in the H-plane from -30 degrees to 30 degrees. One can achieve these properties using a novel unit cell, composed of meshed double-circle rings printed on polymethylmethacrylate substrates, a plastic material transparent to visible light. This unit cell provides a phase shift of 300 degrees for an insertion loss lower than 1 dB at 28.5 GHz. In turn, the TA sources consist of 2 x 2-element arrays of aperture-coupled stacked patch antennas. The choice of a patch array over a horn array allows one to reduce the total profile and weight of the TA. We have fabricated and tested a transparent TA with a diameter of 9.9 wavelengths at 28.5 GHz, yielding a broadside gain of 25 dBi and -1 dB gain bandwidth of 1.8 GHz; the OFF-axis 30 degrees beam presents a peak gain of 21.5 dBi and -1 dB gain bandwidth of 1.4 GHz. The measured results are in good agreement with the simulated ones all over the frequency band of interest.

Background:Social robots are currently a form of assistive technology for the elderly, healthy, or with cognitive impairment, helping to maintain their independence and improve their well-being.Objective:The main aim of this article is to present a review of the existing research in the literature, referring to the use of social robots for people with dementia and/or aging.Methods:Academic databases that were used to perform the searches are IEEE Xplore, PubMed, Science Direct, and Google Scholar, taking into account as date of publication the last 10 years, from 2007 to the present. Several search criteria were established such as "robot" AND "dementia," "robot" AND "cognitive impairment," "robot" AND "social" AND "aging," and so on., selecting the articles of greatest interest regarding the use of social robots in elderly people with or without dementia.Results:This search found a total of 96 articles on social robots in healthy people and with dementia, of which 38 have been identified as relevant work. Many of the articles show the acceptance of older people toward social robots.Conclusion:From the review of the research articles analyzed, it can be said that use of social robots in elderly people without cognitive impairment and with dementia, help in a positive way to work independently in basic activities and mobility, provide security, and reduce stress.

A beam scanning transmitarray antenna (TA) working in the 27.5-29.5 GHz frequency band is presented here. The unit-cell is made of three stacked meshed circular rings printed on Diclad substrates, and provides a 300° phase-shift for an insertion loss lower than 1 dB at 28.5 GHz. The TA is illuminated by a $2\times 2$ -element array of aperture-coupled stacked microstrip patch (ACMP), whose location is shifted in the focal plane to scan the antenna beam in H-plane from −30° to 30°. A TA prototype with a diameter of 9.9 wavelengths has been designed, fabricated and tested. A broadside gain of 25 dBi and −1 dB gain bandwidth of 1.8 GHz have been obtained experimentally.

The QoE measurement has become a novel theme today. To achieve a quality service and minimize the negative impact that traffic on network can cause, it's very important to manage the devices that intervene in this service. Hence, the QoE evaluation allows obtaining benefits both customers and service providers. The main objective of this paper is to measure QoE of a teleconsultation application in Mental Health named Psiconnect, using an approach based on pentagram model. For the QoE evaluation of Psiconnect application we used the pentagram model based on the measurement of 5 factors (integrality, retainability, availability, usability, and instantaneousness). This model allows to design quantifiable metrics for quality evaluations. Using the model cited the value of QoE for Psiconnect is 1.793 (between 1.6 and 1.8). Comparing with Mean Opinion Scores (MOS) test, some users are dissatisfied with the use of the application although the result is near 1.8, so the most of users are satisfied with the use of teleconsultation service based in Skype in the Psiconnect app. There are different models to measure QoE having into account subjective parameters. This is important an estimation of QoE in a quantitative form. Other models can be used to improve the quality of apps.

RF dielectric characteristics of two thermoplastic polymers, namely ABS PC and COP, are here studied with the objective of comparing their specifications for the implementation of antennas for IoT applications. Wideband characterization of these materials is assessed in order to cover the main IoT protocols and UWB communication standard frequencies. In this paper, we are using two completely different techniques to conduct this study. The first is based on ring resonating structures allowing discrete values at resonant frequencies, while the other is the Grounded Coplanar transmission lines (GCPW TL) for continuous results determination. Analysis and discussion of the results are hereby presented.

RF dielectric characteristics of two thermoplastic polymers, namely ABS PC and COP, are here studied with the objective of comparing their specifications for the implementation of antennas for IoT applications. Wideband characterization of these materials is assessed in order to cover the main IoT protocols and UWB communication standard frequencies. In this paper, we are using two completely different techniques to conduct this study. The first is based on ring resonating structures allowing discrete values at resonant frequencies, while the other is the Grounded Coplanar transmission lines (GCPW TL) for continuous results determination. Analysis and discussion of the results are hereby presented.

In this paper, we explore functionalities of MAC layer for three Low Power Wide Area Networks (LPWAN) technologies (LoRa, Sigfox and NB-IoT) dedicated for Smart Cities applications and Internet of Things (IoT). These networks are dedicated to long-range (up to dozens of kilometers) and low rate communication to ensure a good autonomy up to 10 years. The technical differences at the level of MAC layer between Sigfox and LoRa and NB-IoT are explained and evaluated. We apply our simulator to evaluate the performances of these technologies in terms of Packet Error Rate.