Ioana Marcu

Polytechnic University of Bucharest | UPB · Department of Telecommunications

Along with the ubiquity of various Internet of things (IoT) applications, data collection in harsh environments with the help of unmanned aerial vehicles (UAVs) and unmanned surface vehicles (USVs) appears as a popular approach. However, from a networking and transmission perspective, how unmanned vehicles collaborate with each other and with end I...

Multiple access techniques for 5G systems are based on principles related to security, efficiency, and performance increase. Multi-user shared access (MUSA) is included in code-domain non-orthogonal multiple access (CD-NOMA) techniques with multiple benefits including multiple-access interference minimization and system capacity increase. The addit...

In the precision viticulture domain, data recorded by monitoring devices are large-scale processed to improve solutions for grapes’ quality and global production and to offer various recommendations to achieve these goals. Soil-related parameters (soil moisture, structure, etc.) and atmospheric parameters (precipitation, cumulative amount of heat)...

The Perception layer in Internet of Things (IoT) architectures is responsible for connecting sensor nodes and data acquisition units such that sensing devices capture relevant data from the corresponding environment. Most IoT platforms are designed to transmit data at fixed time intervals, which is a disadvantage in the modern world dominated by ra...

In recent years, the Internet of Things concept has rapidly spread in most fields because of the benefits it offers, motivating viticulturists to implement new technologies that increase crop production and quality, as well as streamline production costs. The study's purpose is to monitor, using Internet of Things technology, two methods of identif...

The issue of accurate reception of signals in wireless communication systems is a constant concern due to the presence of noise/fading/interferences that may occur on the transmission path. Acknowledging that 5G requirements for these systems increase the standards related to high throughput and lowest bit error rate (BER), noise reduction must be...

The Internet of Things (IoT) concept has met requirements for security and reliability in domains like automotive industry, food industry, as well as precision agriculture. Furthermore, System of Systems (SoS) expands the use of local clouds for the evolution of integration and communication technologies. SoS devices need to ensure Quality of Servi...

Climate change represents a significant threat to agriculture, food security, and livelihood of millions of people in Europe and across the world. European farming is strongly affected by the high impact of climate change due to rising temperatures, rainfall regimes, and variations in frequency and intensity of extreme climatic events such as flood...

The use of telemetry systems in SMART agriculture is an innovative approach which consists in the implementation of an information system able to provide data on irrigation parameters throughout a year, also taking into consideration other meteorological parameters. The need for a telemetry system for irrigation is emphasized by the market’s intere...

Modern buildings require different IT facilities, therefore integrated communication services have become a must. Although there are already commercial products on the market, most of them need well trained operators, while others require manual and time-consuming operations. The present paper introduces an intelligent displaying and alerting syste...

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,...

Elderly people, as well as people with disabilities, face many mobility problems due to either bone system degradation or various afflictions they suffer. Therefore, any solution that improves the quality of life of these people is more than welcome. This paper aims to present an approach for developing a smart toilet system for ageing people and p...

In a world running out of resources, innovation is the only key for survival. One of the biggest domains affected by the expansion process is the global automotive industry. Sales have reached 90 million automobiles last year, counting a 5% increase compared to year 2016. The real problem comes when parking the car somewhere, at peak hours, when in...

The use of telemetry systems in SMART agriculture is an innovative approach which consists in the implementation of an information system able to provide data on irrigation parameters throughout a year, also taking into consideration other meteorological parameters. The need for a telemetry system for irrigation is emphasized by the market's intere...

Agriculture is the most traditional activity over time. Since the beginning of it, agriculture has suffered many changes to improve productivity and quality of crops. Some of the first significant improvements have been remarked when machines and new tools such as irrigation systems, harvest machines, farmland clearing machines were introduced in t...

Over time, due to the increase in greenhouse gas emissions, several climatic changes have taken place: temperatures have risen, precipitation patterns have changed, glaciers have melted, sea and ocean levels have increased. The contemporary population needs irrigation systems adapted to the current environmental conditions. The introduction of moni...

Modern buildings require different IT facilities, therefore integrated communication services have become a must. Although there are already commercial products on the market, most of them need well trained operators, while others require manual and time-consuming operations. The present paper introduces an intelligent displaying and alerting syste...

The Internet of Things (IoT) is quite used in Smart Agriculture because of the use of IoT sensors that can provide information related to the agricultural fields on which the crops are growing. This paper aims to illustrate the results achieved using evolutionary technologies, i.e., IoT in precision agriculture to monitor environmental factors and...

In multiuser wireless communication systems, signal recovery, even at low BER is a relevant factor for ensuring a safe and reliable communication. Efforts for interference minimization include multiple analysis of source coding/decoding techniques, channel coding/decoding techniques and multiuser detection algorithms. This paper illustrates the imp...

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...

The main purpose of this research is to improve the security of critical computer systems with minimal costs. One of the main problems in such cases is the secondary emissions generated by electronic equipment that, sometimes, might contain confidential information stored inside a secured computer network. The implementation of a set of measures ne...

The future of mobile communication systems challenges researchers to constantly improve efficiency and data rate by performing numerous analyses in lab conditions. The novelty of this analysis is represented by the evaluation of the performances of the systems using two imposed statistical confidence levels (SCLs), parameter which can further provi...

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...

During the past few years, the concept Internet of Things (IoT) has seen a rapid evolution from the point of view of products developed for interconnection. Even if the trend is moving towards a more secure and reliable environment, where, even if people are surrounded by sensors, actuators of intelligent devices, their need for privacy and safety...

Big data storage and processing are considered as one of the main applications for cloud computing systems. Furthermore, the development of the Internet of Things (IoT) paradigm has advanced the research on Machine to Machine (M2M) communications and enabled novel tele-monitoring architectures for E-Health applications. However, there is a need for...

Multiuser detection systems face multiple challenges during communication error correction process when the communication environment is dramatically affected by fading. Depending on the type of channel model that occurs during a communication the bit error rate (BER) can be more or less decreased using appropriate coding/decoding technique. This p...

The present paper analyzes the effect of LDPC coding on the performances of a CDMA DS-SS multiuser system. Two types of detectors are analyzed, namely the conventional matched filter and the MMSE ones, in the ideal case—when the spreading codes are perfectly orthogonal and in a non-ideal one—when the users are more or less intercorrelated. Regardin...

Coding/decoding techniques have become key elements in communication area because of their crucial importance in recovery of the signals at receivers' end. LDPC codes versus turbocodes have been studied in order to improve bit error rate and to increase the capacity of the systems. The present paper illustrates the behavior of multiuser DS-CDMA sys...

Conforming to european standards, starting with the 1st of January 2012 analog TV broadcasting should be completely replaced by digital broadcasting in Romania. In this paper we present a series of measurements done in the 470-790 MHz band, which for the moment still contains both old analog TV stations and new digital ones. An analysis is being ma...

This paper illustrates a detailed analysis of specific problems and limitations of a WSN designed for an environmental protection/wildlife tracking application. Since the main challenge in designing the network is energy minimization for activities that does not concern detection itself, we will concentrate on methods (and results) to achieve that....

This paper investigates the behavior of a CDMA system in conditions of underground propagation collaborated with QPSK modulated signals. The antennas contained in boreholes were modeled as transmission lines. We studied the influence of the impurities of the propagation medium and also presented the role of the dimensions of the drilled cavity that...

In this paper we present a comparative analysis of conventional & MMSE multiuser detectors performances in CDMA systems. At base station end the main reason that affects performances is multiple access interference. It can be caused by non-perfectly orthogonal spreading codes used to differentiate the users or by (im)perfect power conditions. The e...

The area of underground radio technology represents a constant problem among radio communication systems. This paper aims to suggest a possible scenario for transmission/receiving of signals from a salt mine. It is assumed that the system used is a synchronous CDMA system and the users' signals have equal powers. In order for the performances to be...

Multiuser detection technique implies joint demodulation of overlapping data streams of data sent by different users, improving their individual performances based on the knowledge of some key parameters of all users. Each user is identified by its own signature code, which should be, in the ideal case, orthogonal on all the others. Several multius...

This paper presents a geographically distributed mobile teamwork management system that combines the simplicity of Web services architecture and protocols, with the GPS-based location information retrieval, and a geographical mapping application. The aim of our work is to offer a Web-based client-server system heading towards a better management of...

In the latest years multiuser detection systems have supported an increase in design, capacity and performances. Their complex structure requires attention in the process of choosing the appropriate parameters. In CDMA (Code Division Multiple Access) system very important roles in achieving significant performances are played by the power of the si...

The present paper is analysing the occupancy of the radio spectrum for some typical CDMA communications systems. The paper presents also an analysis of how the available channel are used by the communications system and especially of how other available channels could be detected. As example, the paper presents also how the IMT-2000 uplink bands ca...

This paper aims to illustrate the performances of different spreading sequences in mean-square-error linear multiuser systems. The analyzed spreading sequences are Walsh codes (length 8 and 32), PN (pseudo-random) sequences and Gold sequences. Influence of correlation between sequences will be studied and the results are shown as BER (Bit Error Rat...

We will present a security/disaster scenario for a communications system with multiple access and code division in direct sequence where a number of sources communicate concurrently over the same physical channel. Since the main difference between the underground communications and the terrestrial one is the communications medium, we have investiga...

Due to the rapid evolution of mobile communication systems that uses Code Division Multiple Access (CDMA), the importance of multiuser detection increased significantly. This paper aims to illustrate the performances of synchronous Minimum Mean-Square Error (MMSE) multiuser detectors in presence of convolutional coding/decoding and turbo coding and...

Due to the ever-increasing number of radio communication technologies, lack of frequency spectrum has become a serious problem recently. Cognitive Radio (CR) technology promises to be one possible solution to this problem, by allowing access of unlicensed users in licensed bands, based on an opportunistic approach and without interfering with the l...

Lack of frequency spectrum is becoming one of the major problems in the telecommunication field with the introduction of several new radio communication technologies. Cognitive Radio (CR) technology promises to be one possible solution to this problem, by allowing access of unlicensed users in licensed bands, based on an opportunistic approach and...

We present a study of underground wave propagation in dielectrics. We have determined the influence of the impurities of the propagation medium, of the polarization of waves and the effect that reflections have on the transmitted power. As the antennas as borholed in cavities, we have also presented the influence of the dimensions of the drilled ca...

This paper presents some results regarding performance improvement obtained by using turbo encoding technique in conventional and optimal multiuser detector in ideal and non-ideal receiving conditions. The results, expressed as bit error rate as a function of signal to noise ratio, have been obtained after extensive simulations for different encodi...

The paper is analyzing the radio propagation effects in cavities and the interaction with a second type of media, with other dielectric properties. The radiated power is theoretically analyzed and some numerical results are presented.

This paper aims to present the results that can be obtained with a conventional multiuser detector used in conjunction with turbo encoding in order to improve its performance, evaluated in terms of bit error rate (BER) as a function of signal to noise ratio (SNR). We used extensive Monte Carlo simulations, taking into consideration different combin...

The present work aims to illustrate the improvement that turbo encoding / decoding algorithms can bring to a multiuser detection system, evaluated in terms of bit error rate (BER). Extended simulations have been performed for conventional multiuser detection algorithms and are still under study for other algorithms, like the optimal, the MMSE and t...

This paper investigates, based on an interactive Matlab simulation, the turbo encoder and decoder parameters design effects on the overall system performances. Several results are highlighted with respect to different parameter influence on system performances and complexity in the absence/presence of Rayleigh/Rice fading with/without Doppler shift...

This paper investigates some effects of fading channels on the turbo encoder-decode performances, evaluated in terms of Bit-Error Rate BER. Extended Monte Carlo simulations have been developed to determine the effect of Rayleigh / Rice fading, with /without Doppler shift over the performances of a turbo encoder decoder system that uses either helic...