Evaluation of error components in rainfall retrieval from collocated commercial microwave links

Opportunistic rainfall sensing using commercial microwave links (CMLs) operating in telecommunication networks has the potential to complement conventional rainfall monitoring, however, the diversity of sensors and their errors are difficult to handle. This analysis empirically evaluates errors of CML observations that manifest discrepancies between collocated sensors without reference rainfall measurements. Collocated CMLs are evaluated as independent rainfall sensors, which enable us to assess the effect of hardware homogeneity and measurement consistency using CML observations at twelve sites within a real telecommunication network in Prague. The evaluation considers 33 rainfall events distinguishing between stratiform and convective rainfall type in the period 2014 and 2016, monitored in 1-min temporal resolution. Collocated CMLs of identical and different frequencies are evaluated, and different rainfall types are discussed. The collocated commercial microwave links are in excellent agreement. The inherent error of rain-induced attenuation for paired independent commercial microwave links is 0.4 dB. The high correlation of the rainfall intensity measurements between the collocated sensors was obtained in a range between 0.96 and 0.99, and the root mean square error ranges between 0.4 mm h&minus;1 and 1.7 mm h&minus;1. This confirms homogeneous behaviour of the hardware in a real network. Therefore, the data of CMLs of the same characteristics can be processed with identi-cal parameters for rainfall retrieval models.</p

Quantification of a Wet Antenna Attenuation for a Measurement of Rainfall Intensity via the Metropolitan Network of Microwave Links in 10 GHz Band

Commercial microwave links can be utilized as an effective sensor network for a rainfall measurement. However, there are various obstacles that must be overcomed, from which the most significant seems to be an effect of wet antenna attenuation. In this paper, the rainfall calculation has been performed in both a single-link way and an area calculation via the RAINLINK algorithm on the group of real 10 GHz metropolitan microwave links. Conclusion summarizes the resulting wet antenna attenuation values and evaluates the performed measurement

Rain Statistics Investigation and Rain Attenuation Modeling for Millimeter Wave Short-range Fixed Links

Millimeter wave (mmWave) communication is a key technology for fifth generation (5G) and beyond communication networks. However, the communication quality of the radio link can be largely affected by rain attenuation, which should be carefully taken into consideration when calculating the link budget. In this paper, we present results of weather data collected with a PWS100 disdrometer and mmWave channel measurements at 25.84 GHz (K band) and 77.52 GHz (E band) using a custom-designed channel sounder. The rain statistics, including rain intensity, rain events, and rain drop size distribution (DSD) are investigated for one year. The rain attenuation is predicted using the DSD model with Mie scattering and from the model in ITU-R P.838-3. The distance factor in ITU-R P.530-17 is found to be inappropriate for a short-range link. The wet antenna effect is investigated and additional protection of the antenna radomes is demonstrated to reduce the wet antenna effect on the measured attenuation

Challenges in Diurnal Humidity Analysis from Cellular Microwave Links (CML) over Germany

Near-surface humidity is a crucial variable in many atmospheric processes, mostly related to the development of clouds and rain. The humidity at the height of a few tens of meters above ground level is highly influenced by surface characteristics. Measuring the near-surface humidity at high resolution, where most of the humidity’s sinks and sources are found, is a challenging task using classical tools. A novel approach for measuring the humidity is based on commercial microwave links (CML), which provide a large part of the cellular networks backhaul. This study focuses on employing humidity measurements with high spatio–temporal resolution in Germany. One major goal is to assess the errors and the environmental influence by comparing the CML-derived humidity to in-situ humidity measurements at weather stations and reanalysis (COSMO-Rea6) products. The method of retrieving humidity from the CML has been improved as compared to previous studies due to the use of new data at high temporal resolution. The results show a similar correlation on average and generally good agreement between both the CML retrievals and the reanalysis, and 32 weather stations near Siegen, West Germany (CML—0.84, Rea6—0.85). Higher correlations are observed for CML-derived humidity during the daytime (0.85), especially between 9–17 LT (0.87) and a maximum at 12 LT (0.90). During the night, the correlations are lower on average (0.81), with a minimum at 3 LT (0.74). These results are discussed with attention to the diurnal boundary layer (BL) height variation which has a strong effect on the BL humidity temporal profile. Further metrics including root mean square errors, mean values and standard deviations, were also calculated

Rainfall estimates from opportunistic sensors in Germany across spatio-temporal scales

Study region: The study region is Germany and two sub-regions in Germany, i.e. the state of Rhineland-Palatinate and the city of Reutlingen. Study focus: Opportunistic rainfall sensors, namely personal weather stations and commercial microwave links, together with rain gauge data from the German Weather Service, were used in different combinations to derive rainfall maps with a geostatistical interpolation framework for Germany. This kriging type framework considered the uncertainty of opportunistic sensors and the line structure of commercial microwave links. The resulting rainfall maps were compared to two gauge-adjusted radar products and evaluated to three reference gauge datasets in the respective study regions on both daily and hourly basis. New Hydrological Insights for the Region: The interpolated rainfall products from opportunistic sensors provided good agreement to the reference rain gauges. The dataset combinations including information from the opportunistic sensors performed best. The addition of rain gauges from the German Weather Service did not consistently lead to an improvement of the interpolated rainfall maps. On the country-wide, daily scale the interpolated rainfall maps performed well, but the gauge-adjusted radar products were closer to the reference. For the regional and local scale in Rhineland-Palatinate and Reutlingen with an hourly resolution, the interpolated rainfall maps outperformed the interpolated product from DWD rain gauges and showed a similar agreement to the reference as the radar products

Using Remote Sensing Techniques to Improve Hydrological Predictions in a Rapidly Changing World

Remotely sensed geophysical datasets are being produced at increasingly fast rates to monitor various aspects of the Earth system in a rapidly changing world. The efficient and innovative use of these datasets to understand hydrological processes in various climatic and vegetation regimes under anthropogenic impacts has become an important challenge, but with a wide range of research opportunities. The ten contributions in this Special Issue have addressed the following four research topics: (1) Evapotranspiration estimation; (2) rainfall monitoring and prediction; (3) flood simulations and predictions; and (4) monitoring of ecohydrological processes using remote sensing techniques. Moreover, the authors have provided broader discussions on how to capitalize on state-of-the-art remote sensing techniques to improve hydrological model simulations and predictions, to enhance their skills in reproducing processes for the fast-changing world

Cooperative Radio Communications for Green Smart Environments

The demand for mobile connectivity is continuously increasing, and by 2020 Mobile and Wireless Communications will serve not only very dense populations of mobile phones and nomadic computers, but also the expected multiplicity of devices and sensors located in machines, vehicles, health systems and city infrastructures. Future Mobile Networks are then faced with many new scenarios and use cases, which will load the networks with different data traffic patterns, in new or shared spectrum bands, creating new specific requirements. This book addresses both the techniques to model, analyse and optimise the radio links and transmission systems in such scenarios, together with the most advanced radio access, resource management and mobile networking technologies. This text summarises the work performed by more than 500 researchers from more than 120 institutions in Europe, America and Asia, from both academia and industries, within the framework of the COST IC1004 Action on "Cooperative Radio Communications for Green and Smart Environments". The book will have appeal to graduates and researchers in the Radio Communications area, and also to engineers working in the Wireless industry. Topics discussed in this book include: • Radio waves propagation phenomena in diverse urban, indoor, vehicular and body environments• Measurements, characterization, and modelling of radio channels beyond 4G networks• Key issues in Vehicle (V2X) communication• Wireless Body Area Networks, including specific Radio Channel Models for WBANs• Energy efficiency and resource management enhancements in Radio Access Networks• Definitions and models for the virtualised and cloud RAN architectures• Advances on feasible indoor localization and tracking techniques• Recent findings and innovations in antenna systems for communications• Physical Layer Network Coding for next generation wireless systems• Methods and techniques for MIMO Over the Air (OTA) testin

Cooperative Radio Communications for Green Smart Environments

The demand for mobile connectivity is continuously increasing, and by 2020 Mobile and Wireless Communications will serve not only very dense populations of mobile phones and nomadic computers, but also the expected multiplicity of devices and sensors located in machines, vehicles, health systems and city infrastructures. Future Mobile Networks are then faced with many new scenarios and use cases, which will load the networks with different data traffic patterns, in new or shared spectrum bands, creating new specific requirements. This book addresses both the techniques to model, analyse and optimise the radio links and transmission systems in such scenarios, together with the most advanced radio access, resource management and mobile networking technologies. This text summarises the work performed by more than 500 researchers from more than 120 institutions in Europe, America and Asia, from both academia and industries, within the framework of the COST IC1004 Action on "Cooperative Radio Communications for Green and Smart Environments". The book will have appeal to graduates and researchers in the Radio Communications area, and also to engineers working in the Wireless industry. Topics discussed in this book include: • Radio waves propagation phenomena in diverse urban, indoor, vehicular and body environments• Measurements, characterization, and modelling of radio channels beyond 4G networks• Key issues in Vehicle (V2X) communication• Wireless Body Area Networks, including specific Radio Channel Models for WBANs• Energy efficiency and resource management enhancements in Radio Access Networks• Definitions and models for the virtualised and cloud RAN architectures• Advances on feasible indoor localization and tracking techniques• Recent findings and innovations in antenna systems for communications• Physical Layer Network Coding for next generation wireless systems• Methods and techniques for MIMO Over the Air (OTA) testin

Zuverlässigkeitsbewertung von Fahrzeug-zu-Fahrzeug Kommunikation

V2V communication enables a plethora of cooperative applications aimed at reducing road hazard situations as well as enhancing traffic efficiency and individual driving comfort, expanding therewith the boundaries of Advanced Driver Assistance Systems (ADAS). These applications will be supported by IEEE 802.11p, a standard operating in the 5.9GHz frequency band and adapted for the highly dynamic vehicular environment. The focus of this work is V2V safety applications, which have already gained a major attention from the industry, academia, as well as standardization bodies. Being a subject of wireless communication the performance of V2V applications directly depends on the communication link quality and the packet distribution pattern. Therefore, the main purpose of this thesis is to develop an effective communication link reliability assessment method and analyze to what extent V2V communication is feasible to satisfy the reliability requirements of safety applications. Furthermore, we investigate the effectiveness of the proposed assessment method when applied for real-time communication link reliability prediction. In particular, in this work we establish the link between classical network performance metrics and specific application reliability requirements and derive a set of advanced assessment metrics. Afterwards, we investigate through these metrics how different environmental factors affect application reliability based on the measurement data, which was obtained in elaborated real-world measurement campaigns and in different non-line-of-sight scenarios. Using the suggested metrics further in this work we additionally analyze the achievable application reliability of the V2V safety applications in congested network scenarios through the simulation study. Based on these results we also define the most favorable combinations of the network parameters to support reliable operation of these applications. Finally, in this thesis we examine to what extent the suggested metrics are suitable for applications while operating in real time. We develop and implement two frameworks for prediction of the communication link reliability, based on the data that was obtained over the 4.5 months of the simTD project field trials. Furthermore, we apply both frameworks to other measurement data, which was obtained outside the simTD project and assess the effectiveness of both frameworks under independent realistic conditions.Car2Car-Kommunikation ermöglicht eine Vielzahl von kooperativen Anwendungen, welche auf die Unfallverminderung, Verbesserung der Verkehrseffizienz sowie den individuellen Fahrkomfort abzielen und damit die Grenzen von aktiven Fahrerassistenzsystemen erweitern. Im Fokus dieser Dissertation stehen Car2Car-Sicherheitsanwendungen, denen heutzutage bereits große Aufmerksamkeit von Seiten der Industrie, Forschung und diversen Normierungsgremien geschenkt wird. Da alle diese Anwendungen auf drahtloser Kommunikation basieren, ist ihre Leistungsfähigkeit direkt von der Qualität der Kommunikationsverbindung sowie dem Paketverteilungsmuster abhängig. Daher liegt der Hauptfokus dieser Arbeit in der Entwicklung effektiver Methoden zur Bewertung der Kommunikationszuverlässigkeit und der Analyse, inwieweit Car2Car-Kommunikation im Allgemeinen die Anforderungen von Sicherheitsanwendungen erfüllt. Darüber hinaus untersucht diese Doktorarbeit die Effektivität der hier vorgeschlagenen Bewertungsmethoden in Bezug auf die Vorhersage der Kommunikationszuverlässigkeit in Echtzeit-Szenarien. Im Speziellen verbindet diese Arbeit die Welt der klassischen Netzwerkperformance-Metriken mit Car2Car-Anwendungsspezifischen Zuverlässigkeitsanforderungen und stellt als Ergebnis eine Reihe effektiver Bewertungskennzahlen vor. Mithilfe der vorgeschlagenen Metriken wird des Weiteren untersucht, inwieweit verschiedene Umweltfaktoren die Anwendungszuverlässigkeit beeinflussen können. Diese Untersuchung basiert auf Messdaten, die in ausführlichen Feldversuchen in verschiedenen Non-Line-of-Sight-Szenarien gewonnen wurden. Im nächsten Schritt analysiert diese Doktorarbeit die erreichbare Zuverlässigkeit der Car2Car-Sicherheitsanwendungen in Netzwerküberlastungsszenarien anhand einer Simulationsstudie. Als Ergebnis werden die spezifischen Kombinationen der verschiedenen Netzwerkparameter definiert, die einen zuverlässigen Betrieb der Car2Car-Sicherheitsanwendungen gewährleisten können. Zum Abschluss untersucht diese Dissertation, inwieweit die vorgeschlagenen Metriken für die im Echtzeit-Modus funktionierenden Anwendungen geeignet sind. Darüber hinaus werden zwei Frameworks entwickelt und implementiert, welche die Zuverlässigkeit der Kommunikationsverbindung prädizieren. Dies geschieht basierend auf Daten, die während der 4.5 Monate dauernden Feldversuche im Rahmen des simTD Projektes gewonnen wurden. Beide Frameworks werden am Ende anhand unabhängiger Messdaten auf ihre Funktionalität unter realistischen Bedingungen getestet