International Journal of Electronics and Telecommunications

Due to rapid development of wireless systems and future implementation of the 5G system, it is necessary to increase number of the stations and/or number of radio emissions in current and new mobile service frequency bands. For each of the new or modified radio installation in Poland the Electromagnetic Field (EMF) strength levels has to be evaluated and measured/validated in accordance with allowable limits. In the paper the model of estimation of total EMF levels coming from mobile base stations radio emissions to be used for estimation of the whole country territory EMF levels is proposed. Results of preliminary analysis were also shown on practical examples. The model presented in the paper can be used for initial finding of possible places where exist the risk of exceedance of the maximum exposure limits and for analysis of potential radio network development taking into account current regulatory limits. The model will be used in computerized system SI2PEM which is developing in Poland for EMF levels controlling and validation purposes.

Radio environment maps (REMs) are beginning to be an integral part of modern mobile radiocommunication systems and networks, especially for ad-hoc, cognitive, and dynamic spectrum access networks. The REMs will use emerging military systems of tactical communications. The REM is a kind of database used at the stage of planning and management of the radio resources and networks, which considers the geographical features of an area, environmental propagation properties, as well as the parameters of radio network elements and available services. At the REM, for spatial management of network nodes, various methods of propagation modeling for determining the attenuation and capacity of wireless links and radio ranges are used. One method of propagation prediction is based on a numerical solution of the wave equation in a parabolic form, which allows considering, i.a., atmospheric refraction, terrain shape, and soil electrical parameters. However, the determination of a current altitudinal profile of atmospheric refraction may be a problem. If the propagation-prediction model uses a fixed refraction profile, then the calibration of this model based on empirical measurements is required. We propose a methodology for calibrating the analyzed model based on an example empirical research scenario. The paper presents descriptions of the propagation model, test-bed and scenario used in measurements, and obtained signal attenuation results, which are used for the initial calibration of the model.

Massive multiple-input-multiple-output (MIMO) and beamforming are key technologies, which significantly influence on increasing effectiveness of emerging fifth-generation (5G) wireless communication systems, especially mobile-cellular networks. In this case, the increasing effectiveness is understood mainly as the growth of network capacity resulting from better diversification of radio resources due to their spatial multiplexing in macro- and micro-cells. However, using the narrow beams in lieu of the hitherto used cell-sector brings occurring interference between the neighboring beams in the massive-MIMO antenna system, especially, when they utilize the same frequency channel. An analysis of this effect is the aim of this paper. In this case, it is based on simulation studies, where a multi-elliptical propagation model and standard 3GPP model are used. We present the impact of direction and width of the neighboring beams of 5G new radio gNodeB base station equipped with the multi-beam antenna system on the interference level between these beams. The simulations are carried out for line-of-sight (LOS) and non-LOS conditions of a typical urban environment.

This paper presents exemplary exercise on the fundamentals of signal processing course which is offered for second year bachelor level students. Application of Field Programmable Analog Array (FPAA) for pulse amplitude modulation (PAM) exercise is described with signal processing laboratory. There are presented two methods for implementing PAM modulation and demodulation technique in FPAA module. Example configuration files are available form Authors’ web site.

The Bluetooth Low Energy (BLE) MESH network technology gains popularity in low duty IoT systems. Its advantage is a low energy consumption that enables long lifetime of IoT systems. The paper proposes and evaluates new MRT management methods, i.e. exact and heuristic, that improves energy efficiency of BLE MESH network by minimizing the number of active relay nodes. The performed experiments confirm efficiency of the MRT methods resulting in significantly lower energy consumption of BLE MESH network.

In this paper a design of millimeter-wave six-port device for LTCC (Low Temperature Cofired Ceramic) technology is presented. Furthermore, problems with implementation of the project taking into account requirements of LTCC technology are discussed.

Wireless endoscopic capsules can transmit the picture of the inside of the digestive tract to the external receiver for the purpose of gastrointestinal diseases diagnose. The localization of the capsule is needed to correlate the picture of detected anomalies with the particular fragment of intestine. For this purpose, the analysis of wireless transmission parameters can be applied. Such methods are affected by the impact of the human body on the electromagnetic wave propagation that is specific to the anatomy of individual person. The article presents the algorithm of localization of endoscopic capsules with wireless transmitter based on the detection of phase difference of received signals. The proposed algorithm uses simplified human body models that can change their dielectric properties in each iteration to improve the location of the capsule endoscope. Such approach allows to reduce localization error by around 12 mm (15%) and can by used for patients of different physique without the need of the numerical models of individual body.

This article presents a wearable system that localizes people in the indoor environment, using data from inertial sensors. The sensors measure the parameters of human motion, tracking the movements of the torso and foot. For this purpose, they were integrated with shirt and the shoe insole. The values of acceleration measured by the sensors are sent via Bluetooth to a smartphone. The localization algorithm implemented on the smartphone, presented here, merges data from the shirt and the shoe to track the steps made by the user and filter out the localization errors caused by movements the shirt and torso. The experimental verification of the algorithm is also presented.

Nowadays, the technological innovations affect all human activities; also the agriculture field heavily benefits of technologies as informatics, electronic, telecommunication, allowing huge improvements of productivity and resources exploitation. This manuscript presents an innovative low cost fertigation system for assisting the cultures by using dataprocessing electronic boards and wireless sensors network (WSN) connected to a remote software platform. The proposed system receives information related to air and soil parameters, by a custom solar-powered WSN. A control unit elaborates the acquired data by using dynamic agronomic models implemented on a cloud platform, for optimizing the amount and typology of fertilizers as well as the irrigations frequency, as function also of weather forecasts got by on-line weather service.

Code Excited Linear Prediction (CELP) algorithms are proposed for compression of speech in 8 kHz band at switched or variable bit rate and algorithmic delay not exceeding 2 msec. Two structures of Low-Delay CELP coders are analyzed: Low-delay sparse excitation and mixed excitation CELP. Sparse excitation is based on MP-MLQ and multilayer models. Mixed excitation CELP algorithm stems from the narrowband G.728 standard. As opposed to G.728 LD-CELP coder, mixed excitation codebook consists of pseudorandom vectors and sequences obtained with Long-Term Prediction (LTP). Variable rate coding consists in maximizing vector dimension while keeping the required speech quality. Good speech quality (MOS=3.9 according to PESQ algorithm) is obtained at average bit rate 33.5 kbit/sec.

In the article, a validation module, being a component of an integrated system supporting routing in software defined networks (SDNRoute), is proposed and thoroughly examined. The module allows for the verification of the results provided by the optimization module before these results are deployed in the production network. Routing policies are validated for their impact on the network quality parameters and against the threat of overloading (congestion).

Single Frequency Networks (SFN) of transmitters are currently used in television and digital broadcasting to effectively cover large areas using minimal spectral resources and using transmitters with much lower power than if the same area were covered using one transmitter. It is therefore a very ecological solution. In this way, much better reception conditions are obtained in large city areas, as the signal reaches the receiving antenna from different directions, reducing the risk of shading. However, in this type of network one should take into account the loss of signal caused by signal interference. Using the appropriate propagation model, it is possible, with appropriate assumptions, to check how the operation of the third transmitter affects the distribution and size of the deepest fades in relation to the network in which there are two transmitters.

This work presents concepts of the use of algorithms inspired by the functions and properties of the nervous system in dense wireless networks. In particular, selected features of the brain consisting of a large number of nerve connections were analyzed, which is why they are a good model for a dense network. In addition, the action of a selected cells from the nervous system (such as neuron, microglia or astrocyte) as well as phenomena observed in it (e.g. neuroplasticity) are presented.

A spectrum defragmentation problem in elastic optical networks was considered under the assumption that all connections can be realized in switching nodes. But this assumption is true only when the switching fabric has appropriate combinatorial properties. In this paper, we consider a defragmentation problem in one architecture of wavelength-spacewavelength switching fabrics. First, we discuss the requirements for this switching fabric, below which defragmentation does not always end with success. Then, we propose defragmentation algorithms and evaluate them by simulation. The results show that proposed algorithms can increase the number of connections realized in the switching fabric and reduce the loss probability.

This article provides a thorough description of a range of non-standard application cases in which EMC laboratories can be used other than those traditionally associated with this kind of facilities. The areas covered here include investigations of: wireless and radio systems (such as IoT and broadband radio systems) also that require ultra-high operational dynamic range, emulation of interference-free and/or heavilymultipath propagation environment, shielding effectiveness of cabinets and materials (i.e. thin, light and flexible as textiles as well as heavy and thick such as building construction elements).

Localization systems are an important component of Active and Assisted Living (AAL) platforms supporting persons with cognitive impairments. The paper presents a positioning system being a part of the platform developed within the IONIS European project. The system’s main function is providing the platform with data on user mobility and localization, which would be used to analyze his/her behavior and detect dementia wandering symptoms. An additional function of the system is localization of items, which are frequently misplaced by dementia sufferers.

The paper includes a brief description of system’s architecture, design of anchor nodes and tags and exchange of data between devices. both localization algorithms for user and item positioning are also presented. Exemplary results illustrating the system’s capabilities are also included.

The paper discusses the problem of video transmission in an IP network. The authors consider the ability of using the most popular video codecs that use both the MPEG2 Transport Stream and Dynamic Adaptive Streaming over Hypertext Transfer Protocol (DASH). The main emphasis was given to ensuring the quality of service and quality assessment methods, taking into account not only the service- or network provider’s point of view but also the end user’s perspective. Two quality assessment approaches were presented, i.e. objective and subjective methods. The authors presented the results of the quality evaluation for H.264/MPEG-4, H.265/HEVC and VP9 codecs. The objective measurements, proved by statistical analysis of user opinion scores, confirmed the ability of using H.265 and VP9 codecs in both real time and streaming transmissions, while the quality of video streaming over HTTP with the H.264 codec proved inadequate. The authors also presented a connection between the dynamics of network bandwidth changing and MPEG-DASH mechanism operation and their influence on the quality experienced by users.

Paper presents the results of quality assessment of speech and music signals transmitted via DAB+ system with the use of Single Frequency Network (SFN). The musical signals were evaluated in overall quality domain. The subjective research was provided with the use of Absolute Category Rating procedure according to the ITU recommendation and the results have been presented as the MOS values for various bit rates. The speech signals were additionally examined with PESQ method. The results have shown that the assumed quality of 4 MOS, for this kind of broadcasting could be achieved at 48 kb/s for speech and 64 kb/s for music. This fact was confirmed by both: subjective and objective research. The comparison between the results obtained for SFN broadcasting with three emitters with singleemitter broadcast was presented.

This article discusses the traffic types typically used in industrial networks. The authors propose a number of methods of generating traffic that can be used in modeling traffic sources in the networks under consideration. The proposed traffic model have been developed on the basis of the ON/OFF model. The proposed solutions can be applied to model typical traffic types that are used in industrial systems, such as Time-Triggered (TT) traffic, Audio-Video Bridging (AVB) traffic or Best Effort traffic. The article discusses four traffic models with modifications and shows how the proposed models can be used in modeling different traffic types used in industrial networks.

In this paper, impact of changes in parameters of offered traffic on the accuracy of determining the parameters of overflow traffic in hierarchical systems with multi-service traffic was presented. Pascal type traffic streams were offered to the considered systems. The study investigated the impact of changes in the number of sources, intensity of traffic offered by individual classes, as well as changes in the traffic offered by a single free source. The presented results are based on determined relative errors of the values of overflow traffic obtained in simulations and on the basis of calculations.

An Internet application was developed to support the design process of the WLAN access network. The whole program was designed as a desktop application using the following languages: HTML, CSS and JavaScript. The main task of the application facilitates the planning process of the WLAN access network, including the location of multiple base stations. There is an example of using the program in the WLAN network planning process. The main purpose of this application as the ability to carry out network planning using multiple base stations and provide radio coverage for the entire area served by Wireless Internet Service Provider, is obtained.

The article presents the research results of the performance of wireless multi-hop networks. The analysis of the decrease in performance of such networks depending on the number of hops was performed for three popular transmission techniques used in mesh networks: Hybrid Wireless Mesh Protocol (default routing protocol for 802.11s), Optimized Link State Routing Protocol and Wireless Distribution System. Based on the measurements results, mathematical models for the decreasing of network transmission parameters depending on the number of hops were developed.

The article presents the power consumptions measurements performed for three wireless routers operating in IEEE 802.11n standard. A typical consumer-class device Asus RTAC66U was chosen, an operator-class Gateworks Laguna GW2387 and a router built based on the Raspberry Pi3 platform. The aim of experiments was to test the influence of the beacon interframe interval, a client association (joining) in the network and the transmission itself, on the lifetime of battery-powered devices. Theoretical calculations were also performed for the influence of the analyzed scenarios on the battery-powered devices.

An important element of Internet of Things systems (IoT) is wireless data transmission. Narrowband Internet of Things (NB-IoT) and LTE Cat M1 (LTE-M) are the new standards for such transmission intended for LTE cellular networks. Cellular network operators has recently launched such transmission. The article presents the results of measurements of NB-IoT transmission parameters in this network, inside the building and in open urban areas. The main features of the NBIoT system and measuring equipment are briefly discussed.

In the article, the concept, design and realization of the technological demonstrator of a mobile device for generating an electromagnetic curtain (with a name AEGIS) were presented, both in the hardware and software areas. The device is designed to block the radio communication which allow detonating the Radio Controlled Improvised Explosive Devices (RCIEDs). The preliminary laboratory tests of the demonstrator for generating the jamming signal, that were presented in the paper, aimed at assessing the correctness of the device operation and verification of generated signal parameters. On the basis of the obtained results, the ability to jam the cellular systems as well as other radio devices operating in the frequency band from 400 MHz to 2700 MHz was assessed.

A novel algorithm is presented to deduce individual nodal forwarding behavior from standard end-to-end acknowledgments. The algorithm is based on a well-established mathematical method and is robust to network related errors and nodal behavior changes. The proposed solution was verified in a network simulation, during which it achieved sound results in a challenging multihop ad-hoc network environment.

The 6TiSCH communication stack enables IPv6 networking over the TSCH (Time Slotted Channel Hopping) mode of operation defined in IEEE 802.15.4. Lately it became an attractive solution for Low power and Lossy Networks (LLNs), suitable for Industrial Internet of Things (IIoT) applications. This article introduces a credible energy consumption model for the 6TiSCH network nodes, operating in the 863-870 MHz band. It presents the analysis leading to the construction of the model as well as verification through experimental measurements which showed 98% accuracy in determining power consumption for two different network topologies. The article includes reliable battery lifetime predictions for transit and leaf nodes along with other parametric study results.

The aim of the presented paper was to verify the impact of Dynamic PUCCH Resource Allocation Algorithm of the LTE cellular system on the maximum uplink cell throughput and call setup success rate-CSSR. Paper includes the laboratorytestbeddescription and presents the results of an experiment confirming the improvement of both key performance indicatorsKPIs.Apart from the presentation of the Dynamic PUCCH Resource allocation algorithm, the paper also includes a description of legacy LTE uplink (PUCCH and PUSCH) channels dimensioning process thus filling the gap of such a tutorial in the available literature.

In this paper, the future Fifth Generation (5G New Radio) radio communication system has been considered, coexisting and sharing the spectrum with the incumbent Fourth Generation (4G) Long-Term Evolution (LTE) system. The 4G signal presence is detected in order to allow for opportunistic and dynamic spectrum access of 5G users. This detection is based on known sensing methods, such as energy detection, however, it uses machine learning in the domains of space, time and frequency for sensing quality improvement. Simulation results for the considered methods: k-Nearest Neighbors and Random Forest show that these methods significantly improves the detection probability.

The paper is focused on the forthcoming IEEE 802.11ax standard and its influence on Wi-Fi networks performance. The most important features dedicated to improve transmission effectiveness are presented. Furthermore, the simulation results of a new transmission modes are described. The comparison with the legacy IEEE 802.11n/ac standards shows that even partial implementation of a new standard should bring significant throughput improvements.

In paper we present a case study of the radio dispatching communications for providing the voice service during mass events of the “Lednica 2000” Youth Meetings. The presentation is supported by over 20-year experience in organization of this event every year. We also describe a FM radio system deployed during this meeting for broadcasting the English translation.

The paper considers developed and offered an effective algorithm for solving the block-symmetrical tasks of polynomial computational complexity of data processing modular block-schemes designing. Currently, there are a large number of technologies and tools that allow you to create information systems of any class and purpose. To solve the problems of designing effective information systems, various models and methods are used, in particular, mathematical discrete programming methods. At the same time, it is known that such tasks have exponential computational complexity and can not always be used to solve practical problems. In this regard, there is a need to develop models and methods of the new class, which provide the solution of applied problems of discrete programming, aimed at solving problems of large dimensions. The work has developed and proposed block-symmetric models and methods as a new class of discrete programming problems that allow us to set and solve applied problems from various spheres of human activity. The issues of using the developed models are considered. and methods for computer-aided design of information systems (IS).

The purpose of this article is to present three theses – (1) a cultural one: cyberspace is an advanced technical and cultural creation – it is an embodiment of dreams of numerous creators, inventors and engineers; (2) a technical one: security and cyberspace are inseparable components (hence cybersecurity); (3) and a paranoid one: complete security, if achievable, is not a permanent state (hence cyber(in)security). Cyberspace is conceived as a set of digital techniques used to exchange information but also as a new type of social space, partially virtual, which may constitute a being entirely separated from a physical one. A pivotal date for arising of cyberspace may be considered the year 1968 in which routing in the ARPANET network appeared and so did the first programmable logical controller (PLC). For cyberspace this will be the year 1976 – publishing of the key agreement protocol by Witfield Diffie and Martin Hellman. Development of security is correlated with warfare and armament – the military sector has historically made the most significant investments in this area.