Radio Signal Power Research Articles

Wireless Communication-aware Path Planning and Multiple Robot Navigation Strategies for Assisted Inspections

Among the many challenges robots encounter in the mining industry, exploring confined environments receives significant attention. This work tackles problems associated with robot communication in hazardous and confined environments, where its cluttered and extensive nature frequently precludes traditional cable-based and wireless solutions. Our methods resort to off-the-shelf long-range radio frequencies to profile the signal propagation behaviour over the geometrical map to assist navigation algorithms that seek to preserve the connection. We consider mathematical models to predict signal power behaviour and serve as input to path planning. We also propose a semi-autonomous leader-follower scheme, with signal repeater units forming a mobile wireless network to enable inspection in hard-to-reach locations. Finally, we present a multi-robot connection-aware system, combining path planning based on radio signal power with multiple robot navigation. Results show the applicability of the proposed solutions, generating single and multi-robot paths for optimal signal reception based on power estimation, thus enabling operations in remote and isolated areas with no line-of-sight between the command base and the robotic inspection device. Experiments conducted in long corridors and in a representative mining environment using the EspeleoRobô and Pioneer platforms demonstrate significant improvements over the traditional communication methods for robotic operation regarding communication quality and inspection range limits.

A model of radio scintillations in the deep Venus atmosphere: Application to the DAVINCI probe

Power fluctuations have been noted on radio signals propagating through the Venus atmosphere since the very first descent probe there (Venera 4) and have been observed as a routine feature in radio occultations, where the grazing ray geometry amplifies the effect of refractive scattering structures. Motivated by DAVINCI and other missions currently in development, a physical model of refraction variations in the Venus atmosphere is developed using the VEGA-2 high-resolution temperature profile down to the surface and other data, which suggest several distinct layers of more intense scattering. The resultant modeled radio scintillations are compared with observed scintillations and assessed for the DAVINCI relay link. High-time-resolution radio signal power measurements on the DAVINCI radio link promise to be an interesting probe of the Venus atmosphere.

Flickering of a radio-signal due to an atmospheric turbulence

Background. Turbulent fluctuations of the refractive index in the atmosphere lead to distortions during the passage of the radio signal. This can lead to distortion of the transmitted information due to the resulting fluctuations of the amplitude, phase and intensity of the electromagnetic wave that transmits the radio signal. Fluctuations in the intensity of the radio signal lead to flickering of the radio signal on the receiving antenna due to turbulent phenomena in the atmosphere, which are a complex multifunctional physical phenomenon. Aim. The problem of fluctuation of the intensity of the radio signal at the receiving antenna due to atmospheric turbulence is considered the flicker of the radio signal. This problem is currently extremely actual, because there is a tendency of active, negative interference in the process of high-quality transmission of the radio signal on the background of naturally caused turbulent fluctuations. Methods. A theoretical analysis of the passage of a radio signal through a turbulent atmosphere is carried out. The spatial correlation function of fluctuations in the intensity of the received radio signal due to atmospheric turbulence is investigated. Results. The concept of the radio signal flicker characteristic is introduced as the average value of a random variable over the cross section of the receiving antenna the dispersion of the logarithm of the radio signal power. A model of the occurrence of fluctuations in the case of two regions in the cross section of the receiving antenna with different levels of radio signal intensity is calculated. The correlation function for this model is found. Conclusion. Based on the Fourier-spectrum expansion of the two-point spatial correlation function of turbulent fluctuations of the refractive index, the dependence of the flicker characteristic of the radio signal on the wave number of turbulent fluctuations of the atmosphere is found. It is shown that the turbulence of the atmosphere has the greatest effect on the radio signal when the length of the electromagnetic wave is comparable to the scale of turbulent fluctuations.

The results of navigation spacecrafts observations with asymmetry of the onboard antenna amplitude radiation pattern

The received in the Earth surface layer satellite radio signal power depends on the space navigation vehicle onboard antenna parameters, primarily it depends on the amplitude radiation pattern shape. The spacecraft onboard antenna radiation pattern has a complex shape in order to compensate for radio navigation signal power changes as a result of the removal (or approach) of the navigation satellite from the signal consumer. For this reason, the shape of the radiation pattern must have axial symmetry, i.e. it has to be close to the rotation fi gure. As a result of the global navigation satellite system GLONASS radio navigation signals energy characteristics monitoring, VNIIFTRI evaluated amplitude radiation patterns of the onboard antenna-feeder devices of satellites from the orbital constellation, the amplitude radiation patterns asymmetry of some of them was discovered. The asymmetry of the radiation pattern leads to the radio navigation signal (received by the consumer) power dependence on the device angle of the, i.e. on the position of the onboard radiating antenna system of the relative to the signals consumer. The probable reason for the asymmetry is the gradual aging of the active devices in the antenna system. The article purpose is to pay attention of competent specialists to the existing problem.

Сигнальная алгоритмистика программно-конфигурируемого модуля радиомониторинга с частотно-сканирующей разверткой

The paper presents an analysis of scientific and practical development of software-configurable radio monitoring module based on RTL2832U tuner in Simulink environment in order to scan a given ultra-short-wave (VHF) frequency range and perform automatic search, counting and output of the number of broadcasting stations. Given is a structural and circuit diagram of the modernized SDR-receiver (Software Defined Radio) with the inclusion of a balanced mixer, expanding the frequency range of the SDR-receiver from 1.8 GHz to 4.6 GHz. We developed an algorithm for controlling the software architecture of the scanning radio monitoring module, which searches for radio signals in a given band, calculates the spectral power of radio signals, counts the number of detected radio channels.

Application of a Trellis Coded Modulation to Ameliorate the 5G Communication for Tropical Regions

Objectives: To minimize the bit error rate and enhance the radio signal power by an application of the Trellis Coded Modulation (TCM) for the Fifth Generation (5G) technology in tropical regions. Methods: Various diversity techniques have been adopted to diminish the Bit Error Rate. A Communication link model has been proposed in this work and an STBC MIMO system (Space-Time Block Coding multiple-input multiple-output) has been applied to enhance the diversity gain and coding gain of the proposed model. The said model has been implemented in this work for tropical regions for increasing the radio signal power. Findings: The basic climatic feature of tropical regions is a heavy amount of rainfall throughout the year. Because of such rainfall, the radio signal power in these regions gets diminished, and the Bit Error Rate (BER) increases. By applying the proposed communication link model in the tropical regions the Bit Error Rate has been reduced. The values of the Bit Error Rate of the proposed model have been obtained for Rayleigh distribution, Rician distribution and various MIMO techniques. Novelty: A hardware cosimulation block and a 4x4 STBC MIMO has been developed with its subsequent verification on Xilinx Kintex-7 FPGA board. Keywords: Bit error rate; MIMO Systems; Xilinx system generator; Trellis coded modulation; FPGA; Signal attenuation

THE COMPUTER MODELING OF CLASS -D AND -DE SWITCHING-MODE POWER AMPLIFIERS FOR VHF DIGITAL RADIO BROADCAST EQUIPMENT

Currently the transition to digital VHF radio broadcasting is being discussed more and more in different countries, which requires the design of new radio broadcast equipment devices. In classical method of amplifying the power of complex radio signals with a variable envelope, the new broadcast equipment will lose significantly to the existing broadcast equipment with frequency-modulated signal in many energy parameters. The most the promising ways to build high-efficiency broadcast equipment devices of complex radio signals with amplitude-phase modulation and high peak-factor are synthetic methods of linear amplification of radio frequency power (for example, basing on the scheme of L. Kahn) by using high-efficiency switching-mode circuits of powerful amplification. The present state of development of powerful radio-frequency transistors allows to assume that in the near future in the VHF-band switching-mode power amplifiers of Class -D and -F, which will be suitable for building digital radio broadcast equipment with the polar architecture of L. Kahn, will be everywhere used. These switching-mode amplifiers, in contrast to higher-frequency Class-E circuits, supply more steady characteristics in the frequency band. But when developing such broadcast equipment, it is also reasonable to deal with modified switching-mode power amplifiers of the Class -DE and -FE. The article deals with the questions of the computer modeling of switching- mode power amplifiers of Class -D and -DE in relation to the design of VHF radio broadcast equipment.

Generation of a 25-line flattened optical frequency comb and its coherent beating properties.

A 25-line flattened optical frequency comb (OFC) is generated by cascading Mach-Zehnder modulators, and its coherent beating properties are investigated. The effect of bias voltages and the power of radio frequency signals on the flatness of the OFC, and the phase relationships between each comb line are theoretically deduced. In the experiment, a 25-line OFC with a flatness of less than 1 dB and an optical sideband suppression ratio of 12 dB is successfully demonstrated, and the agreement between simulation and experimental results supports the validity of the model for analysis of the flatness. The measured amplitude of harmonic signals by coherent beating of the generated 25-line OFC matches well with the theoretical prediction. A phase noise of -105.31dBc/Hz at 10 kHz frequency offset for the 12th harmonic signal almost without phase noise degradation proves the high coherence of the generated OFC lines.

Design and optimization of structured cables systems for automation of production processes of the enterprise

The object of research is the process of improving the network architecture of enterprises in order to further optimize production processes. The subject of research is the design and optimization of structured cabling systems to automate the production processes of the enterprise. The aim of the work is to improve the method of designing and optimizing structured cabling systems for the transport needs of the cellular network for the needs of the enterprise. The study determined that the process of planning a radio network to automate production processes of the enterprise must be performed in accordance with the following sequence of steps: design of radio network coverage to determine the location of each base station (5G - gNb) and construction of communication transport segment with location cross-country premises. In this paper, research is conducted on the construction of a communication transport segment with the location of cross-country premises. For this purpose, the scope of the statistical method is determined and the choice of the location of the technical premises of the cross floor is substantiated. Conclusions. The research conducted in this paper allowed to develop methods for improving the network architecture of enterprises in order to further optimize production processes. As part of this, a 5G network planning method was developed to automate the production processes of the enterprise, which is to consistently ensure the design of the radio network coverage to determine the location of each base station using an optimized model to estimate the loss of radio signal power. bandwidth, number of connections and reliability and construction of the communication transport segment with the determination of the optimal location of cross-country premises. The developed method makes it possible to plan the optimal structure of the 5G cellular network to optimize production processes, evaluate and reduce the total cost of building the network, while providing the necessary indicators of service quality of network nodes and its reliability.

Stochastic Fading Channel Models With Multiple Dominant Specular Components

We introduce a comprehensive statistical characterization of the multipath wireless channel built as a superposition of scattered waves with random phases. We consider an arbitrary number <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$N$</tex-math></inline-formula> of specular (dominant) components plus an undetermined number of other weak diffusely propagating waves. Our approach covers the cases in which the specular components have constant amplitudes, as well as when these components experience random fluctuations. We show that this class of fading models can be expressed in terms of a continuous mixture of an underlying Rician (or Rician shadowed) fading model, averaged over the phase distributions of the specular waves. The proposed model parameters can be adjusted to tailor the statistical distribution of the received radio signal power to a wide variety of wireless scenarios, some of which are not covered by other state-of-the-art stochastic wireless channel models. In this regard, we verify that the proposed models accurately fit experimental measurements for which their multi-modality cannot be properly captured by other current stochastic models. It is shown that the fluctuations of the specular components have a detrimental impact on performance, and it is formally demonstrated that the lower error rate is obtained when the signal power is concentrated on a single specular component, regardless of whether it fluctuates or not.

CALIBRATION OF HIGH AND ULTRA-HIGH FREQUENCY POWER METERS IN THE RANGE OF UP TO 30 MHZ

High-frequency (HF) and ultra-high-frequency (UHF) power measurements are applied in various industries both in the development and design of radio-electronic equipment and in testing, commissioning, or repair. Since such measurements are one of the basic types of measurement for metrological support in the field of radio engineering and communication, it is necessary to ensure metrological traceability of the calibration of working standards and measuring instruments to standards on fundamental constants in wide frequency and dynamic ranges. The National primary standard of Ukraine for units of power of electromagnetic oscillations in coaxial paths reproduces units of power in the frequency range 0.03 … 18 GHz, and the frequency range of the nomenclature of watt-meters and power converters are much wider – from 9 kHz, and for some types of converters even from direct current. The calibration and measurement capabilities of HF and UHF power measurement of national laboratories of different countries were studied for the possibility of solving the issue of expanding the frequency range of calibration of HF and UHF power meters. The analysis of data on the calibration factor and the efficiency factor in coaxial paths with a resistance of 50 Ohm in the Database of Key Comparisons of the International Bureau of Weights and Measures was carried out. A study of possible solutions was carried out and a scheme was developed to reproduce a unit of power by units of voltage and resistance using a precision voltmeter Boonton 9242 RF for the calibration of measuring transducers Rohde&amp;Schwarz NRP-Z55 and NRP6A in the frequency range from 0.1 … 30 MHz. A reproduction model was created based on the developed scheme, and the contributions of the reproduction model components to the calibration result and the corresponding uncertainties of the model components were estimated. The measurement uncertainty budget was drawn up based on the proposed calibration model of radio signal power measuring transducers.

Radio signal power transfer coefficient between transmitting and receiving antennas with arbitrary polarizations and structures

Radio signal power transfer coefficient between transmitting and receiving antennas with arbitrary polarizations and structures

DEVELOPING SOLUTION FOR USING ARTIFICIAL INTELLIGENCE TO OBTAIN MORE ACCURATE RESULTS OF THE BASIC PARAMETERS OF RADIO SIGNAL PROPAGATION

The article considers the methods of calculating radio signal power. The main factors influencing the distribution and their connection with the error in the calculations of the indicators' peak values are analyzed. The regularities of signal propagation and the correlation between the distance from the radio signal source and the ratio of noise to useful information are determined. These patterns allow us to develop a model of artificial intelligence, which improves the prediction of results compared to existing calculation methods. The obtained results present the efficiency of the offered method.

Absorbing Elements Based on a Uniform Resistive Film for the Implementation of a Wide Range of Radio Signal Power Attenuations

Rectangular and complex-shaped absorbing elements based on a uniform resistive film are used for constructing waveguide, coaxial, and microstrip attenuators. A decrease in the attenuator’s dimensions leads to difficulties in the implementation of low and high attenuations, which requires passing to absorbing elements based on piecewise uniform structures. In this work, topologies of small absorbing elements of the waveguide, coaxial, and microstrip attenuators are proposed to implement a wide range of radio signal power attenuations. They differ from the known elements of attenuators with a two-layer resistive film in terms of their lower temperature stability and sophisticated manufacturing technology. Such attenuation is achieved by using a single-layer resistive film with a central region having a high (cut) or low (conductor) specific resistance. A technique based on the rigorous method of conformal mappings for calculating the proposed absorbing elements is developed. In the considered particular cases, the obtained relations coincide with those known in the literature. Three-dimensional plots of radio signal power attenuation and normalized input resistance as functions of the normalized size of the cut or conductor of the central region are presented. A broad range of possibilities of the control for output parameters of absorbing elements are outlined. The working capacity of the technique is verified by modeling both the equivalent circuit parameters and output parameters of the absorbing elements, namely, input resistance and attenuation, as well as by the analysis of real samples of small add-on absorbing elements of microstrip attenuators with the proposed topologies. The modeling is carried out in the Russian Elcut software package.

Investigating Predictive Capabilities of RBFNN, MLPNN and GRNN Models for LTE Cellular Network Radio Signal Power Datasets

Efficient radio frequency signal coverage planning with well configured transmitters and receivers’ communication channels, is the heart of any cost-effective cellular network design, deployment and operation. It ensures that both network quality and coverage are simultaneously make best use of (i.e. maximized). This work aim to appraise the adaptive learning and predictive capacity of three neural network models on spatial radio signal power datasets obtained from commercial LTE cellular networks. The neural network models are radial basis function neural network (RBFNN), multilayer perceptron neural network (MLPNN) trained with Bayesian regulation algorithms and general regression neural network (GRNN) models. Largely, it is established from the results that ANN prediction methods can tolerate and adapt to measurement errors of attenuating LTE radio signals. Performance comparisons reveal that all the neural network models can predict the propagated LTE radio signals with considerable errors. Specifically, RBFNN delivered the overall best performance with the smallest mean absolute percentage error, root mean square error, mean absolute error and standard deviation values. The GRNN model also gave better prediction results with marginal errors compared to the MLPNN. Thus, the predictive abilities of RBFNN and GRNN models can be explored as a useful tool to successfully plan or fine-tune mobile radio signal coverage area. Keywords: Neural networks; Signal power; attenuating radio signals; radial basis function multilayer perceptron, general regression neural network, Adaptive signal prediction

Northeast Monsoon Effect on Ultra High Frequency (UHF) Signal Attenuation at Kusza Observatory

Northeast (NE) monsoon season in Malaysia was developed due to conjunction with cold air outbreaks from Siberia produce heavy rains, strong wind, and high humidity. This weather condition can affect the radio signal transmission which is crucial to spectrum user. This work investigates the effect of the wet season due to Northeast season on radio signal power within Ultra High Frequency (UHF) band at KUSZA Observatory (KO). Three of weather parameters (wind speed, humidity and rain rate) was considered with the radio signal variation. Measurement of these weather parameters and radio signal power level (dBm) were collected using weather station and spectrum analyzer respectively. From the result obtained, we found that wind speed played a role in radio signal attenuation indirectly. The combination of wind speed (km/h) along with high humidity (%) and rain rate(mm/s) during NE monsoon season have given a significant impact to a radio signal. These findings is useful to radio astronomer to determine the best period for radio astronomical observation with minimum interference considering weather condition. This study will also beneficial to spectrum user such as mobile telecommunication, wireless internet and radio broadcasting in managing and improving their services.

Multi-spectral optical imaging of the spatiotemporal dynamics of ionospheric intermittent turbulence

Equatorial plasma depletions have significant impact on radio wave propagation in the upper atmosphere, causing rapid fluctuations in the power of radio signals used in telecommunication and GPS navigation, thus playing a crucial role in space weather impacts. Complex structuring and self-organization of equatorial plasma depletions involving bifurcation, connection, disconnection and reconnection are the signatures of nonlinear evolution of interchange instability and secondary instabilities, responsible for the generation of coherent structures and turbulence in the ionosphere. The aims of this paper are three-fold: (1) to report the first optical imaging of reconnection of equatorial plasma depletions in the South Atlantic Magnetic Anomaly, (2) to investigate the optical imaging of equatorial ionospheric intermittent turbulence, and (3) to compare nonlinear characteristics of optical imaging of equatorial plasma depletions for two different altitudes at same times. We show that the degree of spatiotemporal complexity of ionospheric intermittent turbulence can be quantified by nonlinear studies of optical images, confirming the duality of amplitude-phase synchronization in multiscale interactions. By decomposing the analyses into North-South and East-West directions we show that the degree of non-Gaussianity, intermittency and multifractality is stronger in the North-South direction, confirming the anisotropic nature of the interchange instability. In particular, by using simultaneous observation of multi-spectral all-sky emissions from two different heights we show that the degree of non-Gaussianity and intermittency in the bottomside F-region ionosphere is stronger than the peak F-region ionosphere. Our results are confirmed by two sets of observations on the nights of 28 September 2002 and 9 November 2002.

A Survey of the DVB-T Spectrum: Opportunities for Cognitive Mobile Users

Cognitive radio (CR) systems are designed to utilize the available radio spectrum in an efficient and intelligent manner. Terrestrial Digital Video Broadcasting (DVB-T) frequency bands are one of the future candidates for cognitive radio applications especially because after digital television transition the TV white spaces (TVWS) became available for radio communication. This paper deals with the survey of the DVB-T spectrum; wideband measurements were performed on mobile platform in order to study the variation of the radio signal power in city area aboard a moving vehicle. The measurement environment was a densely built-in region where the proper DVB-T receiving was guaranteed by three TV transmitters, utilizing three central channel frequencies using 610, 746, and 770 MHz. In our paper the methods, the applied antenna, and measurement devices will be presented together with simulated and measured fading statistics. The final result is an estimation of the cognitive DVB-T spectrum utilization opportunity; furthermore a scenario is also proposed for secondary channel usage.

Cross-Layer Analysis of Energy–Throughput Tradeoff for Relay Networks

In this paper, we study the bandwidth efficiency (throughput) and the energy efficiency of relay networks considering both the physical layer and the medium access control (MAC) layer. Due to wireless signal power attenuation with transmission distance, using a relay for packet transmissions can lead to more energy-efficient wireless networking at the expense of requiring multihop transmissions. To understand the potential benefits of using a relay, the energy-throughput tradeoff needs to be analyzed. In a decentralized wireless network, not only the physical layer but also the MAC layer should be considered. At the physical layer, the transmit power determines the area which contains nodes that might be contending for channel access at the MAC layer. At the MAC layer, gaining access to the channel entails transmitting various signals at the physical layer. This uses energy and takes time, which impacts the bandwidth efficiency. We analyze the energy consumption and the throughput of relay networks as a function of the transmit power. We determine the conditions in which wireless communication using a relay has better energy efficiency or bandwidth efficiency than direct transmission.

FPGA Based Wavelet Trigger in Radio Detection of Cosmic Rays

Experiments which show coherent radio emission from extensive air showers induced by ultra-high-energy cosmic rays are designed for a detailed study of the development of the electromagnetic part of air showers. Radio detectors can operate with 100 % up time as, e.g., surface detectors based on water-Cherenkov tanks. They are being developed for ground-based experiments (e.g., the Pierre Auger Observatory) as another type of air-shower detector in addition to fluorescence detectors, which operate with only ∼10 % of duty on dark nights. The radio signals from air showers are caused by coherent emission from geomagnetic radiation and charge-excess processes. The self-triggers in radio detectors currently in use often generate a dense stream of data, which is analyzed afterwards. Huge amounts of registered data require significant manpower for off-line analysis. Improvement of trigger efficiency is a relevant factor. The wavelet trigger, which investigates on-line the power of radio signals (∼V2/R), is promising; however, it requires some improvements with respect to current designs. In this work, Morlet wavelets with various scaling factors were used for an analysis of real data from the Auger Engineering Radio Array and for optimization of the utilization of the resources in an FPGA. The wavelet analysis showed that the power of events is concentrated mostly in a limited range of the frequency spectrum (consistent with a range imposed by the input analog band-pass filter). However, we found several events with suspicious spectral characteristics, where the signal power is spread over the full band-width sampled by a 200 MHz digitizer with significant contribution of very high and very low frequencies. These events may not originate from cosmic ray showers but could be the result of human contamination. The engine of the wavelet analysis can be implemented in the modern powerful FPGAs and can remove suspicious events on-line to reduce the trigger rate.