Antennas for Mobile Systems

Saunders, S.R.; Aragón‐Zavala, Alejandro

doi:10.1002/9780470294154.ch24

Cited by 38 publications

(58 citation statements)

References 19 publications

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“…It can be estimated either by theoretical modeling or based on direct experimental measurements. The free-space model [21] is the most widely used model. The model is based on the Friis transmission formula, which indicates that, in an ideal environment, the power is spread uniformly over the surface of a sphere surrounding the antenna.…”

Section: Wsn Propagation Modelsmentioning

confidence: 99%

Measurement and Analysis of Near-Ground Propagation Models under Different Terrains for Wireless Sensor Networks

Tang

Wei

et al. 2019

Sensors

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The propagation model is an essential component in the design and deployment of a wireless sensor network (WSN). Although much attention has been given to near-ground propagation models, few studies place the transceiver directly on the ground with the height of antennas at the level of a few centimeters, which is a more realistic deployment scenario for WSNs. We measured the Received Signal Strength Indication (RSSI) of these truly near-ground WSNs at 470 MHz under four different terrains, namely flat concrete road, flat grass and two derived scenarios, and obtained the corresponding path loss models. By comprehensive analysis of the influence of different antenna heights and terrain factors, we showed the limit of existing theoretical models and proposed a propagation model selection strategy to more accurately reflect the true characteristics of the near-ground wireless channels for WSNs. In addition, we implemented these models on Cooja simulator and showed that simplistic theoretical models would induce great inaccuracy of network connectivity estimation.

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Section: Wsn Propagation Modelsmentioning

confidence: 99%

Measurement and Analysis of Near-Ground Propagation Models under Different Terrains for Wireless Sensor Networks

Tang

Wei

et al. 2019

Sensors

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“…Since the outdoor estimates are in 900 MHz equivalent volts per meter, the building penetration loss is equal to 9.5 dB, corresponding to the mean value observed in the literature for this frequency band [ 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 ].…”

Section: Methodsmentioning

confidence: 79%

Design of an Integrated Platform for Mapping Residential Exposure to Rf-Emf Sources

Regrain

Caudeville

Seze

et al. 2020

IJERPH

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Nowadays, information and communication technologies (mobile phones, connected objects) strongly occupy our daily life. The increasing use of these technologies and the complexity of network infrastructures raise issues about radiofrequency electromagnetic fields (Rf-Emf) exposure. Most previous studies have assessed individual exposure to Rf-Emf, and the next level is to assess populational exposure. In our study, we designed a statistical tool for Rf-Emf populational exposure assessment and mapping. This tool integrates geographic databases and surrogate models to characterize spatiotemporal exposure from outdoor sources, indoor sources, and mobile phones. A case study was conducted on a 100 × 100 m grid covering the 14th district of Paris to illustrate the functionalities of the tool. Whole-body specific absorption rate (SAR) values are 2.7 times higher than those for the whole brain. The mapping of whole-body and whole-brain SAR values shows a dichotomy between built-up and non-built-up areas, with the former displaying higher values. Maximum SAR values do not exceed 3.5 and 3.9 mW/kg for the whole body and the whole brain, respectively, thus they are significantly below International Commission on Non-Ionizing Radiation Protection (ICNIRP) recommendations. Indoor sources are the main contributor to populational exposure, followed by outdoor sources and mobile phones, which generally represents less than 1% of total exposure.

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“…Specular reflections only occur at sufficiently smooth material boundaries. This condition is met when the boundary imperfections (

in m) meet the Rayleigh criterion of Equation ( 16 ) [ 52 ]. The grazing angle (i.e., the angle of the impinging rays) is denoted as

.…”

Section: Methodsmentioning

confidence: 99%

“…Specular reflections are calculated according to the Fresnel formulas, with incident and reflected angles being equal to each other (

) [ 52 , 53 , 54 ]. This property is the foundation of multipath assisted systems: because of this predictability, signal paths can be traced, enabling the calculation of a transmitter position, be it in the time domain or angular domain.…”

Section: Methodsmentioning

confidence: 99%

Indoor Multipath Assisted Angle of Arrival Localization

Wielandt

Strycker

2017

Sensors

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Indoor radio frequency positioning systems enable a broad range of location aware applications. However, the localization accuracy is often impaired by Non-Line-Of-Sight (NLOS) connections and indoor multipath effects. An interesting evolution in widely deployed communication systems is the transition to multi-antenna devices with beamforming capabilities. These properties form an opportunity for localization methods based on Angle of Arrival (AoA) estimation. This work investigates how multipath propagation can be exploited to enhance the accuracy of AoA localization systems. The presented multipath assisted method resembles a fingerprinting approach, matching an AoA measurement vector to a set of reference vectors. However, reference data is not generated by labor intensive site surveying. Instead, a ray tracer is used, relying on a-priori known floor plan information. The resulting algorithm requires only one fixed receiving antenna array to determine the position of a mobile transmitter in a room. The approach is experimentally evaluated in LOS and NLOS conditions, providing insights in the accuracy and robustness. The measurements are performed in various indoor environments with different hardware configurations. This leads to the conclusion that the proposed system yields a considerable accuracy improvement over common narrowband AoA positioning methods, as well as a reduction of setup efforts in comparison to conventional fingerprinting systems.

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Antennas for Mobile Systems

Cited by 38 publications

References 19 publications

Measurement and Analysis of Near-Ground Propagation Models under Different Terrains for Wireless Sensor Networks

Measurement and Analysis of Near-Ground Propagation Models under Different Terrains for Wireless Sensor Networks

Design of an Integrated Platform for Mapping Residential Exposure to Rf-Emf Sources

Indoor Multipath Assisted Angle of Arrival Localization

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