Wave Propagation In Urban Environment Research Articles

Complex-Valued Convolutional Neural Networks Design and its Application on UAV DOA Estimation in Urban Environments

Direction-of-arrival (DOA) estimation is an important task in many unmanned aerial vehicle (UAV) applications. However, the complicated electromagnetic wave propagation in urban environments substantially deteriorates the performance of many conventional model-driven DOA estimation approaches. To alleviate this, a deep learning based DOA estimation approach is proposed in this paper. Specifically, a complex-valued convolutional neural network (CCNN) is designed to fit the electromagnetic UAV signal with complex envelope better. In the CCNN design, we construct some mapping functions using quantum probabilities, and further analyze some factors which may impact the convergence of complex-valued neural networks. Numerical simulations show that the proposed CCNN converges faster than the real convolutional neural network, and the DOA estimation result is more accurate and robust.

Supercomputing-Enabled First-Principles Analysis of Radio Wave Propagation in Urban Environments

Wireless communications are expected to take place in increasingly complicated scenarios, such as dense urban, forest, tunnel, and other cluttered environments. A key emerging challenge is to understand the physics and characteristics of wave propagation in these environments, which is critical for the analysis, design, and application of advanced mobile and wireless communication systems. In this paper, we present a full-wave field-based computational methodology for radio wave propagation in complex urban environments. Both transmitting/receiving antennas and propagation environments are modeled by first-principles calculations. A system-level, large scene analysis is enabled by the scalable, ultraparallel algorithms on the emerging high-performance computing platforms. The proposed computational framework is verified and validated with semianalytical models and representative measurements.

Modeling blast waves, gas and particles dispersion in urban and hilly ground areas

The numerical simulation of shock and blast waves as well as particles dispersion in highly heterogeneous media such as cities, urban places, industrial plants and part of countries is addressed. Examples of phenomena under study are chemical gas products dispersion from damaged vessels, gas dispersion in urban places under explosion conditions, shock wave propagation in urban environment. A three-dimensional simulation multiphase flow code (HI2LO) is developed in this aim. To simplify the consideration of complex geometries, a heterogeneous discrete formulation is developed. When dealing with large scale domains, such as countries, the topography is considered with the help of elevation data. Meteorological conditions are also considered, in particular regarding complex temperature and wind profiles. Heat and mass transfers on sub-scale objects, such as buildings, trees and other obstacles are considered as well. Particles motion is addressed through a new turbulence model involving a single parameter to describe accurately plumes. Validations against experiments in basic situations are presented as well as examples of industrial and environmental computations.

High-resolution angle-of-arrival measurement of the mobile radio channel

The accurate planning of microcellular mobile radio networks requires a thorough understanding of the mechanisms that govern radio wave propagation in urban environments. Combined measurements of time delays and angles-of-arrival (AoAs), both in azimuth and elevation, of individual multipath contributions are expected to he very helpful in the validation and improvement of existing ray-tracing propagation models. To this end, we have applied the uniform circular array (UCA)-MUSIC angular superresolution algorithm to complex impulse response measurement data obtained from a synthetic uniform circular array. Beamspace processing and forward/backward averaging were applied to cope with strongly correlated signals. The presented experimental results show that our approach is capable of identifying the dominant multipaths in actual mobile propagation environments.

Parallel irregular software for wave propagation simulation

The objective of the European project STORMS (software tools for the optimization of resources in mobile systems) is to develop a software tool to be used for the design and the planning of the future universal mobile telecommunication system (UMTS). In this context the ParFlow method permits the simulation of outdoor radio wave propagation in urban environment, modelling the physical system in terms of the motion of fictitious microscopic particles over a lattice. This paper gives an overview of the ParFlow method, and reports the design and the implementation of ParFlow++, an object-oriented irregular parallel software for urban outdoor radio wave propagation prediction.

Lattice Boltzmann method for wave propagation in urban microcells

A lattice Boltzmann model which simulates and predicts, on a massively parallel computer, wave propagation in urban environments is presented. This technique takes into account complicated boundary conditions. Two-dimensional simulations are performed starting from a city map and a renormalisation scheme is proposed to extend the results to three dimensions and adjust the wave length. The method, which is simple and easy to implement, provides good path loss predictions when compared with in situ measurements.