KEYWORDS: Global system for mobile communications, Standards development, Receivers, Environmental sensing, Antennas, Networks, Received signal strength, Telecommunications, RF communications, Data communications
Network environment challenges on identifying and direction finder of the emission sources can be performed in several different ways, depending on the spectral inter-frequency and of the equipment used. The tests performed that are still under development will show that there are many different scenarios that may lead to large difficulties in indoor locating of the radio equipment that are registered in standard mobile networks. Therefore, in this paper, we intend to test different receivers from different mobile communication standards with respect to the possibility of identifying and localization and to see the advantages and disadvantages of each generation of standards with respect to this issue.
The Internet of Things (IoT) is a new technology that employs a variety of sensors and wireless communication protocols. People are leveraging IoT to make their lives easier by using innovative and intelligent equipment. This paper presents a new approach, developed in order to increase the reliability in the IoT using the Harris Hawks Optimization (HHO) algorithm in a big data environment. Reliability and availability in big data represents critical criteria for selecting the most suitable protocol. Also, in most scenarios, the sensors' battery cannot be replaced, so energy consumption is another important issue in such IoT system. This research provides an enhanced artificial intelligence approach, based on the HHO technique, to handle load balancing between the Cluster Heads (CH) in a big data environment. A proper load balancing between CHs is vital in sensor network communication since it reduces the energy consumption of the devices. The HHO algorithm selects the appropriate CH by using a hunting technique, that is divided into 2 categorizes, soft besiege and hard besiege. The hunting depends on the remaining energy of the rabbit; at first, rabbit energy is high, but, after a while, the energy of rabbit decreases, so the Harris Hawks attack to this animal in soft besiege. Using this technique, we have tried to balance the energy and reliability of the Internet of Things between CHs. This proposed method was simulated on Network Simulator 3 (NS3).
This paper analyzes the possibility of an attack on an ultrahigh frequency radio frequency identification (UHF RFID) access system and presents some practical results for the systems that are in the ISO 18000-6 standard: we analyze the security breach of an RFID based system, namely the attacks concentrated on the access barriers that have already been installed within an institution. The testing was conducted in normal conditions where no interference was present, then a jammer was introduced transmitting with different transmission power values. It will be identified the situation where the system becomes completely unfunctional, the communication between the RFID reader and the tag is interrupted, the reading of the access code being impossible to perform. This underscores once again the physical radio frequency vulnerability of RFID communication systems, in this case UHF RFID systems.
The purpose of this paper is to validate the existence of vulnerabilities in computer networks - wireless networks which have in their architecture Windows operating systems. In order to demonstrate the vulnerabilities that still exist in windows 10 and windows 11 operating systems, the NetBIOS Name Service, Link Local Multicast Name Resolution, multicast DNS and WPAD protocols will be exploited. By exploiting these protocols, users' access credentials to the systems can be obtained. At the same time, we will propose a series of solutions that will reduce the chances of exploiting these protocols, to increase the security level of the network. Another role of this paper is to show that the use of Wi-Fi networks for the purpose of conveying confidential data is still unsafe. It also highlights the fact that improper use of the operating system Windows can lead to obtaining access data to an attacker who does not need powerful resources. The WPA2 protocol will be exploited to gain access to network resources, to subsequently formulate a series of conclusions aimed at inhibiting or completely reducing these security issues.
As 5/6G technologies are constantly evolving, radio links must be easily designed and analyzed. Focusing on budget and spur analyses for frequency domain concurrently with time domain simulation, the present paper presents a complete and new evaluation approach for radio frequency (RF) links in conformance with matching at the ports of the RF components blocks. Frequency and time domain simulations of RF links allow shorter design time and higher performances in a what-if approach. In the system simulation of the proposed radio link, the signal heritage stipulates if a signal corresponds to the carrier or is a source of intermodulation or distortion produced in the link considering the compression point and leakage from output to the input of power in various points through the link.
Within this paper the authors intend to measure and evaluate the parameters of a WiMax BTS when different interference conditions are existing within its operating area. The measurements were performed in laboratory conditions, in the semianechoic chamber. The effect of variable intensity disturbance interference on the emission parameters of a WiMax base station were measured and analyzed. As a result of these measurements, several situations were analyzed and a number of interesting conclusions were drawn. These measurements have been developed in order to evaluate the effect of a of disruptive interference on the quality of the transmitted signal, as well as the importance of detecting, measuring and analyzing the interference effect on the transmitted signal in different use-case scenarios. The narrowband disturbance signal, with variable intensity, was generated on the 3.623 GHz frequency with the SME 03 Rohde and Schwarz signal generator. Parameter measurements and spectral evaluations were performed with the Anritsu Master Spectrum 2723C spectrum analyzer, tuned to the frequency 3.623 GHz, using transmission and reception antennas in the respective band. An Airspan MacroMAXe-4RX base station, 3600-3700 MHz frequency band, with 5 MHz bandwidth, was used to perform the tests.
This paper presents a new approach regarding the unintended radiation generated by the PS/2 commercial keyboards. It was possible to restore the keystrokes in a controlled environment by receiving the PS/2 bus clock as opposed to receiving the data bus transitions as it has been presented so far in the literature. Examples of keystrokes corresponding to several alphanumeric keys as well as functional keys that are confirmed by galvanic probing of the PS/2 line with an oscilloscope will be presented. The paper presents time domain measurements of the unintended radiation for different keystrokes and also examples of remote reception. We can conclude that the keystroke's compromising radiation can take multiple forms from which the key pressed can be identified with certainty, showing thus a new vulnerability.
The fifth generation (5G) and future wireless networks meet the necessities of a world increasingly more dependent on mobile Internet and mobile phones. Thus, there are a series of technologies that make this possible, part of which are present in this paper. One such technology is where multiple antennas can be used for the receiver/transmitter terminals known as MIMO and evolved to Massive MIMO, where the number of antennas is much higher. Another one is represented by orthogonal frequency-division multiplexing (OFDM) used to mitigate or eliminate the inter-symbol and intra-symbol interferences. Low-density parity-check (LDPC) codes have relatively low and scalable decoding complexity. Therefore, in this paper is proposed a Massive multiuser MIMO system with Manchester source coding, LPDC channel coding and OFDM used by multiple users, when the number of antennas at the receiver varies between 8 and 12. Therefore, taking into account the afore-mentioned technologies and parameters, we analyze the quality of the information that reaches the base station (BS) using extensive Monte Carlo Matlab simulations in terms of bit error rate (BER) versus signal-to-noise ratio (SNR) for pseudorandom (PN) spreading codes, which spreads the OFDM modulated signal with or without Manchester encoding.
KEYWORDS: Orthogonal frequency division multiplexing, Modulation, Antennas, Receivers, Monte Carlo methods, Quadrature amplitude modulation, Signal to noise ratio, Transmitters
The recently implemented 4G network meets nowadays the necessities of a world in a continuous development. Among the new technologies introduced by this standard is the one in which multiple antennas are used at the receiver and at the transmitter ends (MIMO) in order to increase the overall system performances. Massive MIMO is an evolved version of the conventional MIMO that uses a significantly larger number of antennas at the transmitter / receiver. This technology will be included in the much-discussed 5G standard. Another technology that is present in 4G/5G standards is the orthogonal frequency-division multiplexing (OFDM), which is a modulation technique where the information is arranged in blocks of information symbols that are transmitted in parallel on orthogonal subcarriers, as well as new low complexity / high performances encoding techniques. In order to study the enhancement brought by these technologies, in this paper, we propose an uplink Massive MU-MIMO OFDM-based system with low-density parity-check (LDPC) coding used by multiple users which are active simultaneously, when the number of Base Station (BS) antennas varies from 10 to 100. Based on this proposed structure, the transmitter, receiver and communication channel will be simulated in Matlab/Simulink. Extensive Monte Carlo simulation are under development to evaluate the system performances in terms of Bit Error Rate (BER) as a function of Signal to Noise Ratio (SNR).
KEYWORDS: Relays, Antennas, Telecommunications, Sensors, Error analysis, Signal to noise ratio, Signal detection, Computer simulations, Receivers, Monte Carlo methods
In an uplink multiuser system in which the users are situated far enough from the base station (BS), or in which the communication is affected by fading, the use of relays can bring a plus in the quality of the information arrived at the BS. In this paper, the performance of an uplink connection for a Massive MU-MIMO system is analysed with or without relay nodes in order to see how the bit error rate metric (BER) improves when the number of antennas at the base station (BS) is increased from 10 to 100 and for different number of active users that simultaneously require mobile resources to accomplish their momentary needs. For a better evaluation of the proposed system we use, two types of relays, one based on amplifyand- forward (AF) protocol and one on decode-and-forward (DF) protocol. At the BS a maximal ratio combiner (MRC) is used to combine the signals received from users and relay, and a minimum mean-square error (MMSE) detection is applied to recover the information sent by each user. The simulations show that, by using relays, we have a significant gain, especially when the number of the active users is close with the number of antennas from the base station.
This paper presents a new approach to the TEMPEST compromising signals emitted by the printing devices. From the TEMPEST point of view, only the laser printer diodes and the printer-computer communication signals have been considered as compromising signal generators so far. In this paper we will present some examples of video signal recovery from the compromising signal generated by the laser printer LCD display as well as a number of measurement results of the video signal parameters for particular video display signals which have been selected for this reason.
The applicability areas for sensor networks vary from industrial automation, environmental observation to medical domain [1]. As the quality of life has improved, the life expectancy also increased during the last years, fact that leads to an aging of the population. It is well known that elderly people need special treatment and resources due to their decreasing capacity of self-caring. It is, thus, desirable to increase the length of independent living for this category without depriving them from the known life environment and personal habits. Another possible application is the one of child care and monitoring in closed precincts. This paper illustrates the implementation steps of a sensor network used for discriminating between the presence of a human being and of an animal that may be useful in case of medical emergency situations. The design takes into account the main challenges that may occur such as achievement of not accurate results due to the fact that children are moving much more than an adult. The basic structure is designed using Arduino platform, sensors for distance measurements, for height determination as well as DHT22 temperature sensor and sensors for motion detection and takes into account cases of walking and standing subjects. Several configurations have been tested in order to improve the relative error for discrimination between children and pet entering a room.
The rapid growth of wireless communications requires a new generation of multifunction devices operating simultaneously under multiple communication standards, in several bands, small, robust and low cost. Microstrip technology can provide these features. An original topological structure is presented in this paper. It integrates several microstrip lines and lumped components in an asymmetric network, and has three ports. A lot of resonance frequencies occur as a result of combination between normal and degenerate propagation modes. Dual-band and three-bands can be selected, depending on the ports used. The originality of this work is to investigate a pentagonal pattern microstrip and introduces two types of perturbations given by two capacitors and a microstrip line section between the corners of the pentagon. The electric field patterns and insertion loss are calculated and provide the possibility of implementing microstrip and larger flexibility for choosing different frequency bands for wireless applications.
Recently, technological development imposed a rapid growth in the use of data carried by cellular services, which also implies the necessity of higher data rates and lower latency. To meet the users’ demands, it was brought into discussion a series of new data processing techniques. In this paper, we approached the MIMO technology that uses multiple antennas at the receiver and transmitter ends. To study the performances obtained by this technology, we proposed a MIMO-CDMA system, where image transmission has been used instead of random data transmission to take benefit of a larger range of quality indicators. In the simulations we increased the number of antennas, we observed how the performances of the system are modified and, based on that, we were able to make a comparison between a conventional MIMO and a Large Scale MIMO system, in terms of BER and MSSIM index, which is a metric that compares the quality of the image before transmission with the received one.
The objective of this study is to provide an overview of basic technical elements and security risks of RFID communication systems and to analyze the possible threats arising from the use of RFID systems. A number of measurements are performed on a communication system including RFID transponder and the tag reader, and it has been determined that the uplink signal level is 62 dB larger than the average value of the noise at the distance of 1m from the tag, therefore the shielding effectiveness has to exceed this threshold. Next, the card has been covered with several shielding materials and measurements were carried, under similar conditions to test the recovery of compromising signals. A very simple protection measure to prevent unauthorized reading of the data stored on the card has been proposed, and some electromagnetic shielding materials have been proposed and tested.
The home automation system concept existed for many years but in the last decade, due to the rapid development of sensors and wireless technologies, a large number of various such “intelligent homes” have been developed. The purpose of the present paper is to demonstrate the flexibility, reliability and affordability of home automation projects, based on a simple and affordable implementation. A wireless sensing and control system have been developed and tested, having a number of basic functionalities such as switching on/off the light according to ambient lighting and turning on/off the central heating. The system has been built around low power microcontrollers and ZigBee modems for wireless communication, using a set of Vishay 640 thermistor sensors for temperature measurements and Vishay LDR07 photo-resistor for humidity measurements. A trigger is activated when the temperature or light measurements are above/below a given threshold and a command is transmitted to the central unit through the ZigBee radio module. All the data processing is performed by a low power microcontroller both at the sensing device and at the control unit.
In this paper we describe several wearable sensors, designed for monitoring the health condition of the patients, based on an experimental model. Wearable sensors enable long-term continuous physiological monitoring, which is important for the treatment and management of many chronic illnesses, neurological disorders, and mental health issues. The system is based on a wearable sensors network, which is connected to a computer or smartphone. The wearable sensor network integrates several wearable sensors that can measure different parameters such as body temperature, heart rate and carbon monoxide quantity from the air. After the portable sensors measuring parameter values, they are transmitted by microprocessor through the Bluetooth to the application developed on computer or smartphone, to be interpreted.
Modern radars must provide in a very short time: existence, mobility and shape of objects evolving in airspace. Evaluation of the object shapes through active research by using synthetic aperture radar is limited in time, resolution, and cost. A new way of processing non-stationary signals is presented in this article. Signals are obtained from the reflection of the electromagnetic field by objects with complex shape when they are irradiated with linear frequency modulated signals. The amplitude of reflected signal is variable on the radio-impulse duration depending on object shape, causing a certain electromagnetic signature. This phenomenon is caused by specific electromagnetic resonance. The reflected signal has maximum amplitude when the frequency of the incident wave is the same with the resonant frequency of the investigated object. The structure of an radar target can be decomposed into simple geometric shapes such as spheres, ellipsoids, prisms, and so on. Using resonant effect that ensures pattern recognition is exemplified by an object with an aerodynamic profile accepted in many component elements of the aircraft, namely - an ellipsoid. It is a geometric shape used extensively in aviation, because it has a very low aerodynamic resistance. The resonant response of ellipsoid is evaluated in a decade frequency band, but the pattern recognition of this shape is enough for an octave band. The resonant response is assessed for cross polarization of incident electromagnetic field, as well. As a result, the radio-impulse shape can be used in a data base for pattern recognition.
The interframe interpolation method presented consists of partial changing, using the growing size of structuring elements, of the morphological skeleton decomposition subsets of a binary input or grayscale frame with the morphological skeleton decomposition subsets of a binary output or grayscale frame. One of the interpolated frames obtained by this method is similar to the reference frame. Computer simulations illustrate the results.
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