Physics-based statistical model and simulation method of RF propagation in urban environments

• US 20100003991A1
• Filed: 04/27/2006
• Published: 01/07/2010
• Est. Priority Date: 04/27/2005
• Status: Active Grant

• Current Assignee: Lawrence Livermore National Security LLC (Government of the United States of America)
• Original Assignee: Regents of the University of California (University of California)
• Inventors: Pao, Hsueh-Yuan, Dvorak, Steven L.
• Granted Patent: US 7,796,983 B2
• Time in Patent Office: Days
• US Class Current: 455/446
• CPC Class Codes: H04B 17/391 Modelling the propagation channel
• CPC Class Codes: H04B 17/3912 Simulation models, e.g. distribution of spectral power density or received signal strength indicator [RSSI] for a given geographic region
• CPC Class Codes: H04B 17/3913 Predictive models, e.g. based on neural network models
• CPC Class Codes: H04W 16/18 Network planning tools

Abstract

A physics-based statistical model and simulation/modeling method and system of electromagnetic wave propagation (wireless communication) in urban environments. In particular, the model is a computationally efficient close-formed parametric model of RF propagation in an urban environment which is extracted from a physics-based statistical wireless channel simulation method and system. The simulation divides the complex urban environment into a network of interconnected urban canyon waveguides which can be analyzed individually; calculates spectral coefficients of modal fields in the waveguides excited by the propagation using a database of statistical impedance boundary conditions which incorporates the complexity of building walls in the propagation model; determines statistical parameters of the calculated modal fields; and determines a parametric propagation model based on the statistical parameters of the calculated modal fields from which predictions of communications capability may be made.

Claims

1. A method of modeling electromagnetic wave propagation in an urban environment comprising a plurality of buildings and a spatial network therebetween, said method comprising:

dividing the spatial network of the urban environment into a plurality of urban canyon waveguides clad by said buildings and interconnected to each other at intersections defined by waveguide apertures;

propagating an electromagnetic wave through the urban environment to calculate spectral coefficients of modal fields in the waveguides excited by the propagation, wherein the calculation uses a database of statistical impedance boundary conditions of building walls;

determining statistical parameters of the calculated modal fields; and

determining a parametric propagation model based on the statistical parameters of the calculated modal fields.

2. The method of claim 1,

wherein each of said urban canyon waveguides is characterized as having a uniform width and similar electrical properties.

3. The method of claim 1,

wherein the statistical impedance boundary conditions in the database are based on equivalent impedance boundary conditions at reference planes.

4. The method of claim 3,

wherein the equivalent impedance boundary conditions are constructed by taking the ratio of the tangential electric and tangential magnetic fields at the reference planes.

5. The method of claim 1,

wherein the statistical impedance boundary conditions in the database represent different categories of buildings according to predetermined building faç

ade parameters.

6. The method of claim 5,

wherein the building faç

ade parameters are based on at least one of material properties, geometrical locations, sizes and shapes, of said different categories of buildings.

7. The method of claim 1,

wherein the calculation of spectral coefficients of modal fields in the waveguides excited by the propagation uses the modal field at an exit aperture of a first urban canyon waveguide to approximate the modal field at an entry aperture of a second adjacent urban canyon waveguide.

8. The method of claim 1,

further comprising determining communications capability in different zones of the urban environment based on the parametric propagation model.

9. The method of claim 1,

further comprising graphically displaying the communications capability in the different zones of the urban environment.

10. The method of claim 1,

further comprising determining a maximum transmission range from a propagation location based on the parametric propagation model.

11. (canceled)

12. A method of determining communications capability in an urban environment comprising a plurality of buildings and a spatial network therebetween, said method comprising:

receiving transmission parameters as input;

simulating propagation of an electromagnetic wave through the urban environment based on said transmission parameters to calculate spectral coefficients of modal fields in the waveguides excited by the propagation, wherein the calculation uses a database of statistical impedance boundary conditions of building walls;

determining statistical parameters of the calculated modal fields;

determining a parametric propagation model based on the statistical parameters of the calculated modal fields; and

determining communications capability in different zones of the urban environment based on the transmission parameters and the parametric propagation model.