Octavian Fratu

Polytechnic University of Bucharest | UPB · Department of Telecommunications

Smartphones are nowadays extremely popular mobile devices and have the potential to make people”s lives easier, but there are times and places where phones should not be used. A possible solution to this problem is a mobile phone jammer system with the purpose to effectively disrupt the mobile service between the user equipment and the base station...

In this article, we propose a new RIS passive beamforming scheme in two main stages. First, a fingerprint-based codebook (FP-CB) design phase occurs, where the area of interest is divided into a number of points and the optimal reflection patterns (RPs) corresponding to these points are determined and stored alongside the coordinates of these point...

Recently, reconfigurable intelligent surface (RIS) has immensely been deployed to overcome blockage issue and widen coverage for enabling superior performance 6G networks. Mainly, systems use RIS as an assistant to redirect the transmitter (TX) incident signal towards the receiver (RX) by configuring RIS elements amplitudes and phase shifts in a pa...

Aerial reconfigurable intelligent surface (ARIS), is an intelligent reflecting surface (IRS) mounted by unmanned aerial vehicle (UAV), represent a promising candidate for assisting device to device (D2D) millimeter wave (mmWave) communication in temporal and urgent situations, e.g., open-air events. IRS can efficiently mitigate the high blockage im...

One of the key issues with large distributed systems, such as IoT platforms, is gaining timely access to data objects. As a result, decreasing the operation time of reading and writing data in distributed communication systems become essential demands for asymmetric system. A common method is to replicate the data objects across multiple servers. R...

Despite significant advancements in Internet of Things (IoT)-based smart cities, service discovery and composition continue to pose challenges. Current methodologies face limitations in optimizing Quality of Service (QoS) in diverse network conditions, thus creating a critical research gap. This study presents an original and innovative solution to...

Mobile Internet of Things (MIoTs), a promising 5G network application, has begun attracting attention from academia and industry. MIoTs use various sensors and wireless communication protocols. By adopting sophisticated technologies, people are leveraging IoTs to facilitate their tasks. In today's IoT devices, the mobility of the nodes is one of th...

The usage of unmanned aerial vehicles (UAVs) is considered a new technological trend able to solve some challenges of the modern society as dedicated transportation, fast delivery, earth observation, smart agriculture and many others. But there are some challenges related to this fast development: air traffic monitoring, privacy assurance in some s...

Several use cases appear with 5G and beyond networks such as enhanced mobile broadband (eMBB), where ultra-high data rates and low-latency connections become essential demands for asymmetric services, e.g., 8K video streaming and virtual reality (VR). The millimeter-wave (mmWave) band can be a promising player to handle these applications under the...

Intelligent reflecting surfaces (IRSs) became, during the last few years a major player in beyond 5G networks because it can assist millimeter wave and terahertz transmissions to overcome their propagation and blockage issues. IRSs provide the network with alternative line of sight paths and extend the network coverage. However, deploying a single...

mmWave communication is considered a major player for 5G and beyond networks due to its wide unlicensed bandwidth. However, it comes with some challenges such as propagation and penetration losses. To overcome these issues, antenna beamforming is adopted. But it is difficult to estimate massive mmWave multiple input multiple output channel for acti...

Millimeter wave (mmWave) based 5G networks have nowadays attracted researcher from both industry and academia. Because, mmWave can enable dominant 5G services such as ultra-high definition video streaming and virtual reality, by providing them with their requirements, e.g., high data rate and low latency time. But, mmWave channel dynamically change...

Human blockage is one of the key challenges that limit the ability of mm Wave communications to provide ultra-high data rate and ultra-low latency links, thus severely reducing the quality-of-service (QoS) experienced by the users. In this paper, we present the most common human body blockage models, which are used in blockage analysis to predict t...

Intelligent reflecting surfaces (IRSs) became, during the last few years a major player in beyond 5G networks because it can assist millimeter wave and terahertz transmissions to overcome their propagation and blockage issues. IRSs provide the network with alternative line of sight paths and extend the network coverage. However, deploying a single...

With the decrease in the cost and size of drones in recent years, their number has also increased exponentially. As such, the concerns regarding security aspects that are raised by their presence are also becoming more serious. The necessity of designing and implementing systems that are able to detect and provide defense actions against such threa...

This paper presents a technical solution that addresses mission-critical communications by extending the radio frequency coverage area using a flexible and scalable architecture. One of the main objectives is to improve both the reaction time and the coordination between mission-critical practitioners, also called public protection and disaster rel...

In this paper, we offer a brief summary of latest developments in honeypot technologies, used for malware detection and analysis. This includes not only honeypot software, but also methodologies to analyze captured honeypot data. As such, our focus in this work is to keep track of current developments related to traffic analysis, especially honeypo...

With the development of mobile devices and the advent of smartphones, the Internet has become part of everyday life. Any category of information about weather, flight schedule, etc. it is just a click away from the keyboard. This availability of data has led to a continuous increase in connectivity between devices, from any corner of the world. Com...

The world population is growing in an accelerated way urging the need for a more efficient and sustainable agricultural industry. Initially developed for smart cities which face the same challenges caused by an increasing population, Internet of Things (IoT) technologies have evolved rapidly over the last few years and are now moving successfully t...

The development of the telecommunication standards (now we are talking about 5G) lead to us to neglijate the GSM standard, were there are still vulnerabilities that can be exploited by attackers. The porpuse of this article is to demonstrate step by step the authentication in GSM, of mobile subscribers, tehnical parameters and vulnerabilities ident...

In this paper is aimed to analyse and to measure the effect of a disruptive interference on the transmission parameters of a Wi-Fi channel. These measurements are necessary to highlight the changes that occur as a result of disruptive interference and the importance of using software, Spike and Net Analyzer Pro - in detecting, locating, measuring a...

Universal Serial Bus (USB) has become the dominant Plug & Play interface for personal computers and continues to grow. Any digital communication source emits secondary or unwanted emissions, called compromising emanations, as they can be received and used to reconstruct the original transmitted information, thereby compromising the transmitted mess...

Medical IoT (MIoT) or Internet of Medical Things is a new concept aimed to improve e-health services using interconnected medical devices. Medical applications are classified as critical in the context of Internet of Things and, with the new paradigm MIoT, one must analyse and improve every component of IoT architecture to develop reliable platform...

This paper presents a possible solution for an integrated information system for management of activities, designed to be used by public institutions. This solution ensure the information management by making use of resources, activities and software functional modules and applications.The system is flexible, versatile and transparent in terms of a...

In this paper a simple test-bed to evaluate the effect of an unmodulated disrupting signal on a TETRA π/4-DQPSK (Differential Quadrature Phase-Shift Keying) signal has been developed and implemented, such that the transmitted signal does not affect other communication system existing in the same area. An unmodulated disrupting signal, with increasi...

Hazards in industry, wars and serious medical reasons determined the increase of the number of amputations and, thus, the need for designing prosthetics that replace the missing segment by imitating its natural movements. Research in prosthetics domain became, consequently, a primary activity both for engineers and physicians. Due to structural and...

Future 5G networks will demand high increases in capacity which are not acquirable by existing 4G implementations. The objective of this paper is to propose an open testbed solution in order to perform applied studies for 5G New Radio, using SDR, optimal parameter configuration, vendor equipment benchmarking, real life consistent tests for radio eq...

Nowadays, more than ever, agriculture area has to face difficult challenges due to numerous technological transformations used for increasing productivity and products quality. Due to the extended growth in agricultural product use, farmers and big companies operating in the “Big Data” area invest in precision agriculture by using sensor networks,...

This paper presents for the first time a study on the security of information processed by video projectors. Examples of video recovery from the electromagnetic radiation of these equipment will be illustrated both in laboratory and real-field environment. It presents the results of the time parameters evaluation for the analyzed video signal that...

The unprecedented development in the field of electronic and electrical systems with various destinations leads to an agglomeration of the electromagnetic spectrum, but also to the occurrence of interferences and disturbances that affects the normal functioning of the equipment, pollute the environment and affects the functionality of other users....

Monitoring as well as achieving related water quality goals for rivers is a challenge on several scales of both space and time. There are several factors influencing the most effective actions to implement, when it comes to water quality. Collecting water quality data can be challenging and expensive as maintaining specialized equipment can raise c...

The paper proposes a Machine Learning methodology for Android malware detection and recognition, including crypto-mining applications using the blockchain. The design is based on a hierarchical classification method, with several decision stages. A combination of functional and statistical features is proposed to be applied for data classification...

This paper presents a low-cost wireless sign language translator for interpreting and having a conversation between deft and non-deft persons. The system is a glove-like one with sensors embedded in every finger of the glove as to fusion the information from multiple sources and accurately providing an output of the sign language. The paper present...

Home automation systems are expected to develop a new trend, as they embed new technologies and low-cost devices making them suitable for any budget. Nowadays, the researching efforts are dedicated to designing low-power and low-cost smart home systems that offer personalized services considering multiple scenarios that cover usual daily activities...

Software-Defined Networking is no longer just a paradigm, but a novel architecture that is gaining momentum in the industry, covering all aspects of a network, from campus networks and data-centers, to optical transport and microwave networks. In Wireless Transport networks, the emergence of the Microwave Information Model, ONF TR-532, in late Dece...

One of the major drivers of cellular network evolution towards 5G systems is the communication between devices, also known as Machine-to-Machine (M2M) communications. M2M mobile connections will reach an estimated 3.2 billion devices and connections by 2020, which will pose a challenge as the state-of-the-art cellular and wireless networks were des...

The need for insertion of technology in everyday tasks has brought an increase in new methodologies and concepts used to accomplish such objectives. By trying to make technology an enabler for an increasing number of personal or work-related activities, we allow devices to collect data about our way of being, that, if not properly protected and use...

Nowadays it’s rare to find newly opened buildings or under construction sites that don’t aspire to be “smart” or “intelligent”. There are wired systems through the building that offer the basic infrastructure for VoIP systems, TCP/IP communication, IP or CCTV cameras, systems that require low latency and great amounts of bandwidth. Complementary to...

Counting systems are widely used for applications related to counting people within a certain area or traffic monitoring in a crowded commercial area, for automatic settings of air-conditioning systems depending on the number of the persons located in that space, etc. Persons counting and identification systems are useful in educational domain or i...

The Black Sea region is affected by important environmental transformations and EO (Earth Observation) is considered a new way to monitor and, possibly, solve some of its critical issues. The ecological alterations, essentially caused by anthropogenic factors, are the main cause of many transformations such as the ecosystem changes, coastal erosion...

As the importance of communication networks increases in our lives, the limitations of traditional networks start to emerge. Software Defined Networking (SDN) is the most recent paradigm in the networking industry, its purpose being to mitigate traditional network limitations, such as complexity, the difficulty of introducing new services in the ne...

Nowadays, transportation is one of the main air pollution sources and has a significant impact on human health and environmental quality. The electric vehicle is a zero emission vehicle powered by an electric motor with power from an electricity source, usually a battery or super-capacitor. However, monitoring and managing the recharging of electri...

The present paper studies the main characteristics of digital radio relays used by the largest mobile network operator (MNO) in Romania in order to develop a network supporting the newest technologies available on the market. The main contribution is the design of a high capacity Ethernet radio relay network in an area around Bucharest, Romania. Th...

Knowing the noise level measured in saline medium of -118dBm we designed and constructed a complex antenna system with which we measured the signals injected from a generator in this environment. Measurements made with the antenna system in saline environment, have highlighted the signal level of -61.5dBm, much lower than until now. Thus, the atten...

We present a new method for probing the hadronic interaction models at ultrahigh energy and extracting details about mass composition. This is done using the time profiles of the signals recorded with the water-Cherenkov detectors of the Pierre Auger Observatory. The profiles arise from a mix of the muon and electromagnetic components of air shower...

Recent technological advances in the telecommunications industry have led to discovering the limitations of traditional communication networks and, in this context, to the emergence of a new paradigm that tries to mitigate them, namely software defined networking (SDN). SDN is beginning to infiltrate all the aspects of a network, and all kind of ne...

Independent living of older adults is one of the main challenges linked to the ageing population. Especially those living with diseases like COPD, MCI or frailty, need more support in everyday life and this is by itself a big societal challenge with impact in multiple sectors. In this paper we present eWALL, an innovative open-source eHealth platfo...

We present a new method for probing the hadronic interaction models at ultra-high energy and extracting details about mass composition. This is done using the time profiles of the signals recorded with the water-Cherenkov detectors of the Pierre Auger Observatory. The profiles arise from a mix of the muon and electromagnetic components of air-showe...

Software-Defined Networking is no longer just a paradigm, but a novel architecture that is gaining momentum in the industry, covering all aspects of a network, from campus networks and data-centers, to optical transport and microwave networks. In Wireless Transport networks, the emergence of the Microwave Information Model, ONF TR-532, in late Dece...

High-energy particles are extragalactic Cosmic rays are high-energy particles arriving from space; some have energies far beyond those that human-made particle accelerators can achieve. The sources of higher-energy cosmic rays remain under debate, although we know that lower-energy cosmic rays come from the solar wind. The Pierre Auger Collaboratio...

We present a novel method to measure precisely the relative spectral response of the fluorescence telescopes of the Pierre Auger Observatory. We used a portable light source based on a xenon flasher and a monochromator to measure the relative spectral efficiencies of eight telescopes in steps of 5 nm from 280 nm to 440 nm. Each point in a scan had...