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An overview of the main structures of uninterruptible power systems is provided. The impact on internal-system and external-system electromagnetic compatibility of these devices is determined. Contemporary standards and requirements for ensuring electromagnetic compatibility of uninterruptible power systems are analyzed. Features of the structures of uninterrupted power systems such as online, offline and line interactive by the conductive path of propagation of interference are given. The main advantages of eco uninterrupted power supply are summarized. A generalized approach is proposed for the application of radiofrequency interference filters depending on the electromagnetic environment and features of uninterruptible power systems. Refined limitations on the possibilities of adjusting the basic and influence parasitic parameters of the filter links by symmetric and asymmetric propagation of conductive disturbances. The possibility of using remote control of the effectiveness of means of reducing conductive disturbances was assessed. The expediency of localization of control parameters of smart radiofrequency interference filters with the use of artificial intelligence is determined. References 10, figures 6, tables 2.

A novel concept for integrating visible light communications (VLC) with three‐dimensional indoor positioning is presented. A VLC link based on transmitter and receiver characteristics using experimental measurements was modelled. Proposed is a three‐dimensional positioning algorithm using received signal strength indication, which changes based on the angle and distance of the location based service. To reduce inter‐cell interference, the transmitter's location code was sent using different subcarriers. A demonstration shows that the proposed algorithm can obtain a user's position, including height, accurately and without inter‐cell interference.

The performance of an antenna cancellation technique for a multiple-input–multiple-output (MIMO) full-duplex system that is based on null-steering beamforming and antenna polarisation diversity is investigated. A practical implementation of a symmetric antenna topology comprising three dual-polarised patch antennas operating at 2.4 GHz is described. The measurement results show an average of 60 dB self-interference cancellation over 200 MHz bandwidth. Moreover, a decoupling level of up to 22 dB is achieved for MIMO multiplexing using antenna polarisation diversity. The performance evaluation of the proposed technique was performed by simulation and measurement and the results have good agreement.

The development of Low-Power Wide-Area Networks is challenging in urban areas due to the terrain elevation changes, clutter losses or dense vegetation regions that attenuate the radio signals. To provide accurate coverage estimation, signal propagation models that integrate losses caused by reflections or attenuations should be used. In this study, we analyze two radio propagation models used for different urban environment configurations, Longley-Rice and ITU-R, to perform a coverage estimation of a LoRa communication network for large-scale deployments. According to our analysis results, validated by measurements, the Longley-Rice and ITU-R radio propagation models are suitable for an urban environment as they use vegetation path losses and could be adapted according to LoRa modulation requirements. Those propagation models are adjusted for real urban field measurements achieved from a point-to-point communication. The obtained results focus also on coverage optimization of a locally deployed LoRa network, considering the best gateway location for the optimum coverage. Thus, a low-cost deployment of the entire network is ensured by reducing the number of installed gateways.

It is known that the Aeronautical Radio Navigation Systems sharing the Global Navigation Satellite Systems (GNSS) frequency band represent a threat to the satellite-based navigation services. Distance Measuring Equipment (DME) and Tactical Air Navigation (TACAN) systems broadcast strong pulsed ranging signals within the Global Positioning System L5 and Galileo E5a frequency bands where the aviation positioning aids services are allocated. This study provides an experimental assessment of the DME/TACAN interference effect on the GNSS receivers performance in scenarios where the presence of several transmitters in view generates radio-frequency interference hard to mitigate by means of the classical solutions. In detail, analysis in terms of the receiver performance will be presented by showing the effect of the non-ideal pulse blanking on the GNSS signal quality. The optimal set-up of the mitigation process, investigated by means of a software simulation, is provided.

Wireless sensor networks are now used in various fields. The information transmitted in the wireless sensor networks is very sensitive, so the security issue is very important. DOS (denial of service) attacks are a fundamental threat to the functioning of wireless sensor networks. This paper describes some of the most common DOS attacks and potential methods of protection against them. The case study shows one of the most frequent attacks on wireless sensor networks – the interference attack. In the introduction of this paper authors assume that the attack interference can cause significant obstruction of wireless sensor networks. This assumption has been proved in the case study through simulation scenario and simulation results.

Low power levels of global positioning system (GPS) signals make them susceptible to radio frequency interference (RFI) from intentional or unintentional sources. Reliance of safety critical and modern applications on GPS has made GPS critical infrastructure which must be protected. Time-difference-of-arrival (TDOA) is a common approach for locating emitters. The TDOAs are estimated by correlating signals received at different sensor nodes. However, RFI detection can be hampered by the in-band GPS signals which create undesired correlation peaks that can be mistaken for weak RFI. A sub-space projection-based approach for removing the GPS signals and leaving the RFI is proposed, and its performance is evaluated using signals from two synchronised Spirent GPS signal generators captured using a NordNav multi-front-end receiver. The results show that the proposed approach can remove the GPS signals, resulting in better RFI detection and localisation performance under various scenarios.

A new design of a multi-resonance small slot antenna with variable band-notched function for ultra-wideband (UWB) applications is proposed. The proposed slot antenna consists of a square radiating stub and a ground plane with a pair of L-shaped parasitic structures and an inverted T-shaped strip protruding inside the rectangular slit, which provides a wide usable fractional bandwidth of more than 135% (2.98–16.73 GHz), while showing the band rejection performance in the frequency band of 5.05–5.9 GHz to avoid any interference from wireless local area network systems. The designed antenna has a small size of 20 × 20 × 0.8 mm3. Simulated and experimental results obtained for this antenna show that it exhibits good radiation behaviour within the UWB frequency range.

Radio frequency communications are not always possible in hostile electromagnetic environments, and the molecular diffusion channel is considered as an information channel. A binary concentration modulated channel is considered and treated is the uncertain arrival time of particles as the main source of inter-symbol interference. The analysis derives the bit-error-rate and data rate expressions for a diffusion channel with zero drift. The minimum error rate and maximum data rate are derived analytically. It is also found that in order for reliable communications to be possible, the delay time must be greater than a threshold that is proportional to the square of the communication distance.

In this study, the authors investigate the outage probability of underlay cognitive radio systems with relay selection. In particular, they consider a secondary multi-relay network operating in the amplify-and-forward (AF) mode and only the ‘best’ relay is selected, which satisfies an index of merit. The proposed selection strategy takes into consideration the effect of primary user (PU) interference. That is, the authors assume that the secondary multi-relay network is exposed to unwanted interference from a neighboring PU network. They derive a closed-form outage probability expression and further present a thorough asymptotic diversity order analysis of the underlying scenario. A simulation study is presented to corroborate the analytical results and to have further insight into the performance of the proposed selection strategy.