Wireless Signal Distribution Research Articles

Analysis of the radio signal distribution for controlling unmanned aerial vehicles

It is of great importance to create a radio communication algorithm for the communication of flight units with ground stations and the exchange of information. To this end, this article analyzes the interference in the path of propagation and propagation of the radio signal for flight control.

Online joint localization without user interactions

Wi-Fi fingerprinting has been a popular indoor localization due to the widespread layout of indoor WLAN. However, the signal fluctuations in the complex environments make it difficult to maintain high accuracy localization for the received signal strength (RSS) fingerprinting. Various positioning solutions have emerged to address this challenge, either working in stand-alone mode or in collaborative mode. In the former case, the user only utilizes his own RSS observation to request location service, while the latter usually requires information transfer between users. Considering the spatial correlation of wireless signal distribution, we propose an online joint localization scheme (JointLoc) that does not require direct interaction between users. The fact that the signals observed by users in physical proximity characterize the surroundings is used by JointLoc to identify neighboring users for joint localization. Besides this, JointLoc further integrates a novel subset-based localization scheme, thus the influence of anomalous RSS signals is eliminated before making the final location decision. We have fully evaluated the performance of JointLoc in two RSS datasets collected in real environments. Compared with conventional algorithms and the latest ones, results show that JointLoc is robust against signal fluctuations, and achieves good localization accuracy.

The Concept of Designing Moscow Cellular Telecommunication Network of B5G Generation

The paper presents a general analysis of global trends in the development of the 5th generation cellular telecommunication network. Concrete ways of their implementation on the scale of a megapolis city are proposed. As an example, a draft design of the Moscow cellular network of the B5G generation was carried out with the distribution of radio signals in pico cells in the 37—43.5 GHz band. Comparison with the key parameter "peak data rate in a cell", achieved in 4G LTE cellular networks and expected in B5G networks, showed a multiple increase, which indicates the effectiveness of the proposed approach.

Fingerprint Fusion Location Method Based on Wireless Signal Distribution Characteristic

In the context of the rapid development of the Internet and the Internet of Things technology, services based on location information have received more and more attention, and people gradually have higher expectations for the quality and experience of positioning services. At present, outdoor positioning technology is becoming mature, but different from empty outdoor areas, there is a highly complex indoor environment with many interference factors, so it is difficult to receive effective satellite signals. To realize the smooth transition of whole-field positioning, it is necessary to study an economical and efficient indoor positioning technology. The existing indoor positioning technologies have some problems, so this paper comprehensively uses the resource-rich Wi-Fi signal, Frequency Modulation (FM) signal and Digital Terrestrial Multimedia Broadcast (DTMB) signal as the positioning data sources, and proposes a fingerprint fusion positioning method based on the wireless signal distribution characteristic. Experiments show that the proposed method improves localization accuracy by 30% compared to localization with Wi-Fi alone.

ASTF: Visual Abstractions of Time-Varying Patterns in Radio Signals.

A time-frequency diagram is a commonly used visualization for observing the time-frequency distribution of radio signals and analyzing their time-varying patterns of communication states in radio monitoring and management. While it excels when performing short-term signal analyses, it becomes inadaptable for long-term signal analyses because it cannot adequately depict signal time-varying patterns in a large time span on a space-limited screen. This research thus presents an abstract signal time-frequency (ASTF) diagram to address this problem. In the diagram design, a visual abstraction method is proposed to visually encode signal communication state changes in time slices. A time segmentation algorithm is proposed to divide a large time span into time slices. Three new quantified metrics and a loss function are defined to ensure the preservation of important time-varying information in the time segmentation. An algorithm performance experiment and a user study are conducted to evaluate the effectiveness of the diagram for long-term signal analyses.

An analytic description of the radio emission of air showers based on its emission mechanisms

The spatial signal distribution of the radio frequency radiation from extensive air showers on the ground contains information on crucial cosmic-ray properties, such as energy and mass. A long-standing challenge to access this information experimentally with a sparse grid of antennas is an analytic modeling of the radio signal distribution, which will be addressed in this contribution. We present an analytic model based on the two physical processes generating radio emission in air showers: the geomagnetic and the charge-excess emission. Our study is based on full Monte-Carlo simulations with the CoREAS code. Besides an improved theoretical understanding of radio emission, our model describes the radio signal distribution with unprecedented precision. Our model explicitly includes polarization information, which basically doubles the information that is used from a single radio station. The model depends only on the definition of the shower axis and on the parameters energy and distance to the emission region, where the distance to the emission region has a direct relation to the cosmic-ray mass. The model describes the true signal distribution precisely such that the model uncertainties are negligible compared to typical experimental uncertainties.

Evolution of Radio-Over-Fiber Technology

Radio-over-fiber technology provides a simpler pathway for the distribution of wireless signals in broadband wireless networks via optical means. The technology has evolved over the last 30 years, with many challenges already overcome and with many more to address. This paper provides an overview of the technology evolutionary path of RoF with a review of its past, evaluation of its present, and a discussion of its challenges into the future.

An analytic description of the radio emission of air showers based on its emission mechanisms

Ultra-high energy cosmic rays can be measured through the detection of radio-frequency radiation from air showers. The radio-frequency emission originates from deflections of the air-shower particles in the geomagnetic field and from a time-varying negative charge excess in the shower front. The distribution of the radio signal on the ground contains information on crucial cosmic-ray properties, such as energy and mass. A long standing challenge is to access this information experimentally with a sparse grid of antennas. We present a new analytic model of the radio signal distribution that depends only on the definition of the shower axis and on the parameters energy and distance to the emission region. The distance to the emission region has a direct relation to the cosmic rays mass. This new analytic model describes the different polarizations of the radiation and therefore allows the use of independently measured signals in different polarization, thereby doubling the amount of information that is available in current radio arrays, compared to what has been used thus far. We show with the use of CoREAS Monte Carlo simulation that fitting the measurements with our model does not result in significant contributions in both systematic bias and in resolution for the extracted parameters energy and distance to emission region, when compared to the expected experimental measurement uncertainties. This parametrization also enables fast simulation of radio signal patterns for cosmic rays, without the need to simulate the air shower.

A mixed methods approach for locating the missing H-209 aircraft

ABSTRACTWe investigated the disappearance of the 4-engine H-209 aircraft along its route from Moscow, Russia to Fairbanks, Alaska in August 1937 operated by Levanevsky and a crew of five people. A radiogram analysis indicates that the aircraft could have crashed in the Alaska Range and thus analysis centered on this region was performed. A mixed methods approach was used to find the missing plane, including examining aircraft radio messages, historic newspapers, and information from witnesses and participants in the H-209 search expeditions; creating a geographical information system that utilized satellite imagery, GMTED-2010 topography, knowledge of polar navigation principles using astronomical instruments, and the spatial distribution of radio signals in the Alaska Range. In one satellite image a plane crash was located near the top of the Mt. Deception and the fuselage-to-wing ratio indicates a configuration typical of low-speed cargo aircraft of the 1930s–1940s.

Bayesian Online Learning for Information-based Multi-Agent Exploration with Unknown Radio Signal Distribution

Exploring an unknown environment with multiple robots is an enabling technology for many useful applications. This paper investigates decentralized motion planning for multi-agent exploration in a field with unknown received signal strength (RSS) distribution. The environment is modelled with a Gaussian process using Bayesian online learning by sharing the information obtained from the measurement history of each robot. Then we use the mean function of the Gaussian process to infer the multiple RSS source locations. The inferred source locations are modelled as the probability distribution using Gaussian mixture-probability hypothesis density (GM-PHD) filter. This modelling enables nonparametric approximation of mutual information between source locations and future robot positions. We combine the variance function of the Gaussian process and the mutual information to design an informative and noise-robust planning algorithm for multiple robots. The experimental performance is analyzed by comparing with the variance-based planning algorithm.

Measurement of cosmic rays with LOFAR

The LOw Frequency ARay (LOFAR) is a multipurpose radio-antenna array aimed to detect radio signals in the 10 – 240 MHz frequency range, covering a large surface in Northern Europe with a higher density in the Northern Netherlands. Radio emission in the atmosphere is produced by cosmic-ray induced air showers through the interaction of charged particles with the Earth magnetic field. The detection of radio signals allows to reconstruct several properties of the observed cascade. We review here all important results achieved in the last years. We proved that the radio-signal distribution at ground level is described by a two-dimensional pattern, which is well fitted by a double Gaussian function. The radio-signal arrival time and polarization have been measured, thus providing additional information on the extensive air shower geometry, and on the radio emission processes. We also showed that the radio signal reaches ground in a thin, curved wavefront which is best parametrized by a hyperboloid shape centred around the shower axis. Radio emission has also been studied under thunderstorm conditions and compared to fair weather conditions. Moreover, by using a hybrid reconstruction technique, we performed mass composition measurements in the energy range 1017 – 1018 eV.

Experimental investigation of the optical Wigner processor

An acoustooptic Wigner processor was constructed and investigated. The processor operating at the frequency about 130 MHz permits to get the time-frequency distribution of radiosignals. The experiment carried out for linear frequency modulated signals showed that this device has an advanced resolution and frequency determination precision in comparison with the acoustooptic current spectrum analyzer.

Transport Schemes for Fiber-Wireless Technology: Transmission Performance and Energy Efficiency

Fiber-wireless technology has been actively researched as a potential candidate for next generation broadband wireless signal distribution. Despite the popularity, this hybrid scheme has many technical challenges that impede the uptake and commercial deployment. One of the inherent issues is the transport of the wireless signals over a predominantly digital optical network in today’s telecommunication infrastructure. Many different approaches have been introduced and demonstrated with digitized RF transport of the wireless signals being the most compatible with the existing optical fiber networks. In this paper, we review our work in the area of digitized RF transport to address the inherent issues related to analog transport in the fiber-wireless links and compare the transmission performance and energy efficiency with the other transport strategies.

Distribution of Broadband Services Over 1-mm Core Diameter Plastic Optical Fiber for Point-to-Multipoint In-Home Networks

This paper presents a point-to-multipoint (P2MP) in-home optical network infrastructure based on 1-mm core diameter plastic optical fiber (POF). By employing passive POF splitters, converged broadband wired and wireless service transmission over a P2MP POF infrastructure is demonstrated. A gross 2.2 Gb/s fractional discrete multitone (DMT) and a 528-MHz ultra wideband (UWB) wireless signal distribution simultaneously to four end-users are successfully achieved with BER <; 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-3</sup> and EVM <; 15.5% , respectively. Up to 50 m transmission distance is achieved using off-the-shelf optical components. This feasibility study on all-optical P2MP infrastructures presents a promising low-cost solution for high-speed in-home broadband communication.

Multistandard Wireless Transmission Over SSMF and Large-Core POF for Access and In-Home Networks

An end-to-end transmission of coexisting multistandard radio (LTE, WiMAX, and UWB) signals is demonstrated for the first time with the transmission over a combined access and in-home networks consisting of 25-km SSMF, 25-m large-core diameter polymethylmethacrylate graded-index plastic optical fiber link and 1-m wireless. The residential gateway includes O-E-O conversion to connect the access and in-home parts of the networks. This letter demonstrates a fully integrated radio signal distribution scenario from the central station to the end-user personal area networks.

Adaptive energy detection of quasi-deterministic signals in the presence of the non-Gaussian noise

Analytical expressions for the parameters of the adaptive energy detection of the quasi-deterministic radio signals in the presence of the Lichter noise are derived. The effect of the random amplitude distribution of radio signals on the decision statistics of detection is analyzed.

Spatial and Temporal Distribution of the VHF/UHF Radio Waves in Built-Up Land Communication Links

We present a unified approach of the description of the spatial and temporal distribution of radio signals within built-up radio communication links. This approach is based on a multiparametric stochastic model, which takes into account the characteristic features of built-up terrain and peculiarities of radio wave propagation related with multiple reflections, diffraction and scattering phenomena caused by obstructions surrounding both terminal antennas, the receiver and the transmitter. To describe fast fading phenomena, we propose a new general distribution of signal strength fast fading, which successfully covers the Ricean distribution in line-of-sight (LOS) and quasi-LOS conditions and the Rayleigh distribution in no line-of-sight multipath conditions usually used for description of land communication links. This new distribution leads to a multiparametric stochastic model. Based on this model, we present a strict estimation of scales of slow and fast fading and present the corresponding correlation functions in space and time domains, which describe slow and fast signal fluctuations. Finally, the power distribution in the angle-of-arrival (azimuth) domain, following the proposed stochastic approach, is considered and analyzed, both for uplink and downlink mobile communication channels

Efficient characterization of harmonic and intermodulation distortion effects in dispersive radio over fiber systems with direct laser modulation

Theoretical and experimental radio over fiber (RoF) system performance is studied in the presence of fiber dispersion and directly modulated DFB laser chirp. The measurements determine the distortion terms of the links with G-652 fibers. Agreement with the computed values validates the model, used presently in RoF link design for wireless-signal distribution. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 46: 114–117, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20917

Software Radio—a key technology for adaptive access

AbstractThe paper provides a vision of an adaptive wireless access for next‐generation services. Depending on the requirements of the applications and the user situation, an optimum access method has to be selected. Software (SW) radio is the key enabling technology in this field. The functionality of a SW radio is described, and the challenges for future developments are identified. A major advantage of SW radio is the on‐the‐fly upgrade capabilities, both of terminals and of base stations. The paper concludes with a presentation of future trends, hybrid fibre distribution of radio signals and mechanisms for control of the various access networks. Copyright © 2002 John Wiley &amp; Sons, Ltd.