Multi-Elliptical Geometry of Scatterers in Modeling Propagation Effect at Receiver

In the proposed chapter, the authors present a geometric-statistical propagation model that defines three groups of received signal components, i.e., direct path, delayed scattering, and local scattering components. The multi-elliptical propagation model, which represents the geometry of scatterer locations, is the basis for determining the delayed components. For the generation of the local components, a statistical distribution is used. The basis for this model is a power angular spectrum (PAS) of the received signal, which is closely related to a type of propagation environment and transmitter-receiver spatial positions. Therefore, we have an opportunity to evaluate the influence of the environment type and an object motion direction on the basic characteristics such as envelope distribution, PAS, autocorrelation function, and spectral power density. The multi-elliptical model considers the propagation phenomena occurring in the azimuth plane. In the chapter, we will also show the 3D extension of modeling effects of propagation phenomena

Analysis of Position Angle of Arrival in Multipath Fading Channel using Correlated Double Ring Channel Model for VANET Communications

Correlated Double Ring channel modeling in the mobile to mobile communication system (M2M) and vehicular based communication system was pointed out. This modeling required the transmitter and receiver were randomly moving and surrounded by scatterers in a static ring. The scatterers’ positions were placed randomly at the radius of the ring of transmitter and receiver. Received signals were measured based on complex envelope parameters. Two signals propagation scenarios were implemented, they were signals of Rayleigh and Rician distributed. In order to calculate the Rayleigh and Rician complex envelope values, there were some parameters involved which were Angle of Arrival (AoA) and velocity of transmitter and receiver that created Doppler effects. The effects of AoA parameter were investigated towards envelope complex values of Rayleigh and Rician according to predetermined various velocities and scatterers’ positions were divided into four positions criteria. The simulation result shows that for scheme 2 at velocity 40 m/s, distribution magnitude for Rayleigh is 0,1 and Rician is 0,5. It concludes that Rician distribution always outperforms Rayleigh distribution for all predetermined velocities and this scheme give the largest magnitude over all. This is because of the closest distance between scatterers of transmitter and receiver. Also, certain velocities range over all scatterers’ positions, the magnitude of Rayleigh and Rician complex envelope have similar graphic tendency.Correlated Double Ring channel modeling in the mobile to mobile communication system (M2M) and vehicular based communication system was pointed out. This modeling required the transmitter and receiver were randomly moving and surrounded by scatterers in a static ring. The scatterers’ positions were placed randomly at the radius of the ring of transmitter and receiver. Received signals were measured based on complex envelope parameters. Two signals propagation scenarios were implemented, they were signals of Rayleigh and Rician distributed. In order to calculate the Rayleigh and Rician complex envelope values, there were some parameters involved which were Angle of Arrival (AoA) and velocity of transmitter and receiver that created Doppler effects. The effects of AoA parameter were investigated towards envelope complex values of Rayleigh and Rician according to predetermined various velocities and scatterers’ positions were divided into four positions criteria. The simulation result shows that for scheme 2 at velocity 40 m/s, distribution magnitude for Rayleigh is 0,1 and Rician is 0,5. It concludes that Rician distribution always outperforms Rayleigh distribution for all predetermined velocities and this scheme give the largest magnitude over all. This is because of the closest distance between scatterers of transmitter and receiver. Also, certain velocities range over all scatterers’ positions, the magnitude of Rayleigh and Rician complex envelope have similar graphic tendency

Dosimetric study of the radiolectric influence of humans into complex environments through determistic simulations and the implementation of a simplified model

The research presented in this thesis falls under the framework of dosimetry and deterministic estimations. A dosimetric study is carried out with the aid of a 3D Ray Launching simulation technique, by means of an in-house developed code at UPNA. Dosimetry is defined as the calculation of the absorbed dose when a tissue is exposed to electromagnetic radiation, in this case, non-ionizing radiation. It has reached a great importance since a part of the society starts to show concern about the exposure of people to artificial exposures caused by mobile phones or Wi-Fi networks. In fact, some entities (administrations and health bodies) are involved in the regulation and the release of guidelines about this subject. The objective of this thesis is to study dosimetry through 3D Ray Launching simulation technique, calibrating it by the implementation of several scenarios where the simulation tool is tested throughout the comparison of theoretical and measurement results. A simplified human body has been also developed with the aim of employing it in different scenarios, performing dosimetric estimations and providing insight on its influence in the electromagnetic power distribution inside an indoor scenario. Finally, obtained results are compared with different guideline thresholds giving an idea of the compliance of the law when usual wireless communication systems are emitting.Programa Oficial de Doctorado en Tecnologías de las Comunicaciones (RD 1393/2007)Komunikazioen Teknologietako Doktoretza Programa Ofiziala (ED 1393/2007

Evaluation of electromagnetic dosimetry of wireless systems in complex indoor scenarios with human body interaction

In this work, the influence of human body within the estimation of dosimetric values is analyzed. A simplified human body model, including the dispersive nature of material parameters of internal organs, skin, muscle, bones and other elements has been implemented. Such a model has been included within an indoor scenario in which an in-house 3D ray launching code has been applied to estimate received power levels within the complete scenario. The results enhance previous dosimetric estimations, while giving insight on influence of human body model in power level distribution and enabling to analyze the impact in the complete volume of the scenario.The authors wish to acknowledge the financial support of project FASTER, funded by the Consejería de Industria, Gobierno de Navarra

A Novel 3D Analytical Scattering Model for Air-to-Ground Fading Channels

A geometry-based three-dimensional (3D) novel stochastic channel model for air-to-ground (A2G) and ground-to-air (G2A) radio propagation environments is proposed. The vicinity of a ground station (GS) is modelled as surrounded by effective scattering points; whereas the elevated air station’s (AS) vicinity is modelled as a scattering-free region. Characterization of the Doppler spectrum, dispersion in the angular domain and second order fading statistics of the A2G/G2A radio communication channels is presented. Closed-form analytical expressions for joint and marginal probability density functions (PDFs) of Doppler shift, power and angle of arrival (AoA) are derived. Next, the paper presents a comprehensive analysis on the characteristics of angular spread on the basis of shape factors (SFs) for A2G/G2A radio propagation environments independently in both the azimuth and elevation planes. The analysis is further extended to second order statistics of the fading channel; where the behaviour of the level crossing rate (LCR), average fade duration (AFD), auto-covariance and coherence distance for the A2G/G2A radio propagation environment is studied. Finally, the impact of physical channel parameters, such as the mobility of AS, the height of AS, the height of GS and the delay of the longest propagation path, on the distribution characteristics of Doppler shift, angular spread and second order statistics is thoroughly studied

HEVA: Cooperative Localization using a Combined Non-Parametric Belief Propagation and Variational Message Passing Approach

This paper proposes a novel cooperative localization method for distributed wireless networks in 3-dimensional (3D) global positioning system (GPS) denied environments. The proposed method, which is referred to as hybrid ellipsoidal variational algorithm (HEVA), combines the use of non-parametric belief propagation (NBP) and variational Bayes (VB) to benefit from both the use of the rich information in NBP and compact communication size of a parametric form. InHEVA, two novel filters are also employed. The first one mitigates non-line-of-sight (NLoS) time-of-arrival (ToA) messages, permitting it to work well in high noise environments with NLoS bias while the second one decreases the number of calculations. Simulation results illustrate that HEVA significantly outperforms traditional NBP methods in localization while requires only 50% of their complexity. The superiority of VB over other clustering techniques is also shown

Machine Learning in Wireless Sensor Networks: Algorithms, Strategies, and Applications

Wireless sensor networks monitor dynamic environments that change rapidly over time. This dynamic behavior is either caused by external factors or initiated by the system designers themselves. To adapt to such conditions, sensor networks often adopt machine learning techniques to eliminate the need for unnecessary redesign. Machine learning also inspires many practical solutions that maximize resource utilization and prolong the lifespan of the network. In this paper, we present an extensive literature review over the period 2002-2013 of machine learning methods that were used to address common issues in wireless sensor networks (WSNs). The advantages and disadvantages of each proposed algorithm are evaluated against the corresponding problem. We also provide a comparative guide to aid WSN designers in developing suitable machine learning solutions for their specific application challenges.Comment: Accepted for publication in IEEE Communications Surveys and Tutorial