numerical and graphical solvers for urban propagation capri wireless school sept. 13 -17, 2004 1/116...

1/116Numerical and Graphical Solvers for Urban Propagation

Capri Wireless School

Sept. 13 -17, 2004

University Federico II of Napoli (Italy)

Numerical and Graphical Solvers for Urban Propagation

Daniele Riccio



Sept. 13 -17, 2004

University Federico II of Napoli (Italy)


Daniele RiccioJoint work with:

Giorgio Franceschetti

Antonio IodiceGiuseppe Ruello



Sept. 13 -17, 2004

Approaches to solve a problem (1)

• In the Academy…

1°

2° 3°

Theory

Solution Resources



Sept. 13 -17, 2004

Approches to solve a problem (2)

• In a Company…

1°

2° 3°

Resources

Solution Theory



Sept. 13 -17, 2004

Approches to solve a problem (3)

• Mixed way

1°

2° 3°

Solution

Resources Theory



Sept. 13 -17, 2004

Which is the problem?

• Plan the radio coverage for a wireless network operating in an urban area

Solution = Maxwell Equations+ constitutive relationships + boundary conditions+ initial conditions

0b

d

jd

h

be

t

t

No simple solution for complex environments



Sept. 13 -17, 2004

What sort of network?

• It depends on your boss:

1-Owner of a large company →

2-Director of a local division →

Example planUMTS Italy

≈ 10000 Base stations

Example planUMTS Capri

1-3 Base Stations



Sept. 13 -17, 2004

1-The boss is the owner of a large company



Sept. 13 -17, 2004

2-The boss is the director of a local division



Sept. 13 -17, 2004

Stochastic or Deterministic approach?

1-Owner of a large company →

2-Director of a local division →

Example planUMTS Italy

≈ 10000 Base stations

Example planUMTS Capri

1-3 Base Stations

Stochastic

Deterministic



Sept. 13 -17, 2004

Deterministic approachWhat do we need?

• Solutions → Software Tools for:•Antenna (or antennas) optimal location

•Position•Orientation•Input power…….

•Antenna optimal parameters•Radiation patterns•Input power…….

•Best server

•…………

Does it exist one “core” software tool (CoreST)?



Sept. 13 -17, 2004

What problem can the “core” tool solve?

… over a prescribed scene

Evaluation, in the phasor domain, of the radiated field

For a prescribed antenna…



Sept. 13 -17, 2004

Which is the problem, now?

• Evaluate, in the phasor domain, the radio coverage for a wireless network operating in an urban area

Solution = Maxwell Equations+ constitutive relationships + boundary conditions

No exact analytical solutions for complex environments

0B

D

JDH

BE

Ρ

i

i



Sept. 13 -17, 2004

What can I do with the electromagnetic field prediction?

• Increase SNR• Increase channel capacity• Reduce the cost for bandwith• Reduce biological effects



Sept. 13 -17, 2004

Is there any other problem that can be solve?

• GSM planning• UMTS multipath• Mobile• WLAN• indoor



Sept. 13 -17, 2004

CoreST rationale

• Deterministic Approach

• Direct ray tracing

• 3D scansion

Only some years ago following such a strategy was

considered to be

IMPOSSIBLE



Sept. 13 -17, 2004

Microwaves

Geometrical Optics

Two kinds of ray tracing algorithms

• Inverse Algorithms (proper ray tracing) – all feasible paths between site and receiver are explored, and field value at receiver is calculated from contributes.

• Direct Algorithms (ray launching) - rays span the scene and are followed until a threshold value is reached. At each sample point field is evaluated.

PROPAGATION: RAY TRACING TECHNIQUES

Pros: accuracy, global computation (Best Server, Network Planning )

Cons: computation load

Pros: faster, e.g. graphic 3D rendering

Cons: only feasible for end-to-end links



Sept. 13 -17, 2004

Electromagnetics

Reflections

Geometric optics approximation

Scattering

Classical or fractal electromagnetic models

Diffractions

Diffractions are evaluated by means of the most advanced UTD techniques

Program rationale



Sept. 13 -17, 2004

Procedure stops when the field level undergoes a sensitivity threshold

Output The whole field value map is provided as well as a coverage map.

End of program

Program rationale



Sept. 13 -17, 2004

HP projection. VP projection

Buildings have vertical walls

Radiation diagrams are projected on HP and VP

Horizontal plane (HP) - Vertical plane (VP)

Program rationale



Sept. 13 -17, 2004

Input Data :

Antenna tablePosition, rad. diagr., …

Building tableVertex position, height,

Algorithm rationale

Horizontal plane analysis



Sept. 13 -17, 2004

Pixel Scanning

For each pixel:

evaluate its polar coordinates, assign the pixel to an anxel.

Algorithm rationale




Sept. 13 -17, 2004

Building scanning

For each wall:

assign the wall to anxels (and evaluate distances);

For each vertex:

evaluate its polar coordinates, assign the vertex to an anxel.

Algorithm rationale




Sept. 13 -17, 2004

At the end of the scanning:

for each anxel we have three lists, sorted by distance from the source:

•pixels list, •walls list, •vertexes list.

Algorithm rationale




Sept. 13 -17, 2004

For each anxel: Vertical plane analysis.Scanning (from lower to higher distances from the source) of “objects” in the anxel: pixels, walls and vertices (wedges).

Vertical plane analysis

Algorithm rationale



Sept. 13 -17, 2004

Accuracy dependence on anxel width

Algorithm rationale



Sept. 13 -17, 2004

INPUTS

Sensibility threshold

Receiver Height

Output Resolution

Rays Maximum Distance

Diffraction Order

Keyboard

Vector File Raster File

Planet File

Frequency Gain H Pattern

V Pattern

Site Coordinates

Antenna Height

Polarization Input Power

Input Resistance

Downtilt Alignment

Keyboard

Planet File

- -

Soil dielectric permittivity (complex)

Wall permittivity (complex)

Wall thickness

Glass permittivity (complex)

Glass thickness

Percentage of windows area in

the wall

Indoor specific attenuation factor

Default value • Downtown

• Residential

• Agricultural and Vegetated Land

Residential Area

Historical Area

Office Area

File

ANTENNA

SCENE ELECTROMAGNETIC PARAMETERS

CONTROL AND CHECKTOPOGRAPHY



Sept. 13 -17, 2004

Inputs



Sept. 13 -17, 2004

Acknowledgment

WISE – WIde SEnsing



Sept. 13 -17, 2004

Resources – InputMan power in months

Academy

Professor 4

Researcher 8

Ph.D.Student

Graduate Student 48

Industry

Senior Engineer

Engineer

Junior Engineer 12



Sept. 13 -17, 2004

7 matrixes, related to the calculation at street level and on the rooftops:

(complex)

(real)

summations extended to the number of rays which arrive to the point with a fieldlevel upper than the threshold

(real)

for each building, 1 vector, with length equal to the number of floors (only last simulation)

comparison with the measured field in the points of the raster where it is available

|Etot| in raster geo-referred format file for later comparisons with other simulations

rate between the power of the strongest channel and the sum of all the others iso- frequency in the superposition areas ( C/I )

Measure units: Volt/m, Watt/m2, dBmVolt/m, dBmWatt/m2

i

ixx EE i

iyy EE i

izz EE

i

2

ixx EE i

2

iyy EE i

2

izz EE

2

z

2

y

2

xtot EEEE

OUTPUT: Numerical



Sept. 13 -17, 2004

•for street level, building floor and roof:

•Layers management ( Prediction , Buildings, Measure )

•Color options (Grey levels / Rainbow colors, Gamma correction)

•Zoom

•2D / 3D visualization

OUTPUT: Display

|Etot|, in false colors or grey levels

|Ex|, |Ey| and |Ez|, in color levels (RGB)

Ex, Ey and Ez numerical value readable moving the mouse on the map

Best Server

the points where the measured field is available (read by file)

Tools:



Sept. 13 -17, 2004

Output



Sept. 13 -17, 2004

Resources – OutputMan power in months

Academy

Professor 5

Researcher 7

Ph.D.Student

Graduate Student 36

Industry

Senior Engineer

Engineer

Junior Engineer 12



Sept. 13 -17, 2004

Operational Modes

Single Source (Single map, single antenna)

Coherent and incoherent field levels, related to the area illuminated by the antenna.

Interference (Single map, up to three antennas)

Incoherent field related to the different antennas, individuation of the antenna

which better serves each point , superposition areas, C/I.

Best Server (Single map, more than three antennas)

Best server.

Measured values (Single map, single antenna)

Position of the points on the map, numerical values, comparison with predicted values.



Sept. 13 -17, 2004

for i=1,Nmax do beginfor j=1,Mmax do begin

xcoord[i,j]=r[i,j]*cos(teta[i,j])ycoord[i,j]=r[i,j]*sin(teta[i,j])

endforendfor

xcoord=r*cos(teta)

ycoord=r*sin(teta)

All-in-one math operations on arrays:

E.g.: polar to Cartesian coordinates

SPEED UP: IDL BUILT-IN FEATURES

1,1 1,2 …

2,1 … …

… … n,n

1,1 1,2 …

2,1 … …

… … n,n

Speed up:

15 x - 50 x



Sept. 13 -17, 2004

USER-LEVEL FLOW CHART

Direct rays

Terrain ProfileBuildings Map

Buildings E.M. dataDiffracted

rays

Reflected rays

Diffracted rays

interactions Outdoor field

calculation

Indoor field

calculation

Incoherentvectorial

field(/L << 1)

Coherent vectorial

field(/L >> 1)

Total fieldpower

MoreSites?

New site location

Antenna parameters

Simulation options

yes

Site location Rx threshold

Simulation options

Planet file:

Measuredfield

comparison

Graphic interface:

Irradiation patternPolarisation pattern

Antenna Planet file:



Sept. 13 -17, 2004

IMPROVEMENTS IN-PROGRESS (2)

LIFO discipline in source handling

Less memory requirements

Source Loading

Ray tracing



Sept. 13 -17, 2004

POLARISATION

Antenna polarisation

input parameter

E, E

referenced

to ray

E, E// referencedto surface

Ex, Ey, Ez in UTM

reference

Output

Reflection/Diffraction

Propagation

E

E

E

E//

EyEx

Ez



Sept. 13 -17, 2004

GIS

GIS aimed investigation– How to operate on spatial data? Computational geometry

– How to manage data? DBMS

– How to export data to GISs? Tiff Geo-data



Sept. 13 -17, 2004

PROPAGATION: a simple example…

…of how LOS coverage changes depending on terrain profile:



Sept. 13 -17, 2004

PROPAGATION: DTM shading

• Terrain profile influences radio propagation in GO model:

The building is now partially out of LOS

No field because of closer to source points

Reasonable diffractive contribution from natural edges?



Sept. 13 -17, 2004

PROPAGATION: Antenna pattern into account

• An analytical pattern was used in the test:

Vertical patternHorizontal pattern

]360,0[],90,90[

)(),( 3

||

20

)360(

20

eeet



Sept. 13 -17, 2004

PROPAGATION: reflected radiation pattern

• Reflected source radiation pattern imprint:

V/m dBmW/m2



Sept. 13 -17, 2004

PROPAGATION: diffracted radiation pattern

• Diffracted source radiation pattern imprint:

V/m dBmW/m2



Sept. 13 -17, 2004

PROPAGATION: real antenna

• Antenna: Kathrein 741 786

Antenna height: 12 m Downtilt: 3°Terrain height range:[-20,+30] m w.r. to antenna



Sept. 13 -17, 2004

PROPAGATION: real antenna (2)

• Antenna: Kathrein 741 415

Antenna height: 15 m Downtilt: 3°Terrain height range:[-27,0] m w.r. to antenna



Sept. 13 -17, 2004

SPATIAL DATA: computational geometry (1)

Point: A 0-dimensional object that specifies geometric location specified through a set of coordinates (E.g. Vertex)

Line segment (vector): A 1-dimensional object that is a direct line between two end points (E.g. Wall)

Polyline: A 1-dimensional object built-up as a set of connected line segments; describes linearly extended objects. Closed polylines are used to describe object with 2-dimensional extension (E.g. Building perimeter)



Sept. 13 -17, 2004

SPATIAL DATA: computational geometry (2)

OPERATION DEFINED IN TYPE APPLICATION

line intersection line x line point wall across anxel

point in area point x area bool point in anxel

line proximity line x line bool close buildings

point in line point x line bool diffractive vertex

line in area line x area bool indoor floor belonging

line-area inters. line x area pointN indoor shading

area in area area x area bool plane building belonging

area inters. area x area line, point building shading

• Basic operations for 2½ D topological analysis:



Sept. 13 -17, 2004

DATABASE SYSTEMS

• Hierarchical DBMS:

A B

a

b

c

d

e

f

g12

3 4

5

6

V

A B

a b c d d e f g

1 12 2 3 3 4 4 61 61 4 4 5 5



Sept. 13 -17, 2004

DATABASE SYSTEMS

• Network DBMS:

V

A B

a b c d e f g

1 2 3 4 5 6

A B

a

b

c

d

e

f

g12

3 4

5

6



Sept. 13 -17, 2004

DATABASE SYSTEMS

• Relational DBMS:

A B

a

b

c

d

e

f

g12

3 4

5

6



Sept. 13 -17, 2004

Resources – AlgebraMan power in months

Academy

Professor 3

Researcher 4

Ph.D.Student

Graduate Student 12

Industry

Senior Engineer

Engineer

Junior Engineer 2



Sept. 13 -17, 2004

DIFFRACTION COEFFICIENT

• Perfectly conducting or perfectly absorbing wedges:

asymptotic evaluation of exact solutions for f .

• Dielectric wedges: Heuristic generalisation of the formula for perfectly conducting wedges.

It provides intermediate results between the two ideal cases, and is usually in better agreement with measurements.



Sept. 13 -17, 2004

DIFFRACTION: THEORY

UTD EXACT FORMULA FOR DIELECTRIC WEDGE:

020ctg0

//,020ctg

//,

020ctg

020ctg

sin24exp

,0

,//,

kLaFn

RkLaFn

nR

kLaFn

kLaFn

n

jD

Where:

X

djjXXjXF 2expexp2 and

2

2cos2 2 Nn

a

WHAT DOES EACH TERM MEAN?

wave-spherical sin

wave-lcylindrica

2

1

1

1

1

dd

dd

dd

dd

L



Sept. 13 -17, 2004

DIFFRACTION: THEORY

WHAT KIND OF PROBLEM DO WE HAVE TO SOLVE?

• : angle between incident ray and wedge in the plane of incidence

• n : the wedge angle is (2-n)

• 0 : angle between plane containing incident ray and illuminated face of wedge

• : angle between plane containing diffracted ray and illuminated face of wedge

• d1: distance between primary source and edge

• d : distance between edge and illuminated point

• N+,- : integer which most nearly satisfies equations 2nN±−() = ±

• : reflection coefficient for either parallel or perpendicular polarization for face = 0, incidence angle 0

• : reflection coefficient for either parallel or perpendicular polarization for face = n, incidence angle (n−0)

0

//,R

nR //,



Sept. 13 -17, 2004

DIFFRACTION: PROCEDURE

• Evaluating diffraction coefficient is not only a local problem: to evaluate it we need to know distance between edge and illuminated point

• It is necessary to recognized what kind of illumination we have: spherical (reflected or direct field) or cylindrical (diffracted ray)

• The procedure must recognize when we have either one or two reflection boundary

• For any illuminated edge, we only store information about the wedge and the distance between the primary source and the wedge; for any illuminated point, we use this information to evaluate the field

HOW CAN WE USE UTD LIMITING EVALUATION TIME?



Sept. 13 -17, 2004

DIFFRACTION: POLARIZATION

POLARIMETRIC REFLECTION COEFFICIENTS

000000 DDIDIDEE nnnnid BB

2

,0,2

,0//,,0,,0//,

,0,,0//,2

,0,2

,0//,,0

cossin- cossin

cossin sincos

nnnn

nnnnn

RRRR

RRRRB

22

1

sincos

coscoscos



Sept. 13 -17, 2004

DIFFRACTION: horizontal wedges

PROBLEM

HORIZONTAL DIFFRACTED RAYS LIE IN PLANES NOT CONTAINED IN VERTICAL PLANE; THE EXSTENSION OF VERTICAL PLANE LAUNCH IS NOT IMMEDIATE



Sept. 13 -17, 2004


TWO APPROACHES

DIRECT APPROACH INVERSE APPROACH

•For any ray illuminating the horizontal wedge we try to represent the whole Keller cone

•We launch a set of vertical plane covering the same area of the set of Keller cone generated from analyzed edge

•In scanning points along an anxel we reconstruct path trough horizontal edge



Sept. 13 -17, 2004


OUR CHOICE

INVERSE APPROACH

•Direct method was not so natural in this case

•The impact on evaluation time is almost non-existent

•No need of new resources (time, memory space)

•Good agreement with direct results

•No threshold



Sept. 13 -17, 2004


HOW DOES IT WORK?

•In scanning a vertical plan, if we intersect a horizontal

wedge, we store the information about the incident field for each

incident anxel

•For the following points on the ground, we check which has an view angle smaller

than the Keller cone’s aperture



Sept. 13 -17, 2004


HOW DOES IT WORK?

90

•Vertical plan

•Horizontal plan



Sept. 13 -17, 2004


HOW DOES IT WORK?

20

•Vertical plan

•Horizontal plan



Sept. 13 -17, 2004


EXAMPLE

Direct and reflected field

Horizontally diffracted field



Sept. 13 -17, 2004

Diffraction: example



Sept. 13 -17, 2004


• Galleria Umberto, without diffraction– Illumination: 37%

– Evaluation time: 41 s



Sept. 13 -17, 2004


• Galleria Umberto with diffraction– Percentage of illumination: 71%– Evaluation time : 11m 21s



Sept. 13 -17, 2004

Resources – DiffractionMan power in months

Academy

Professor 6

Researcher 10

Ph.D.Student

Graduate Student 38

Industry

Senior Engineer

Engineer

Junior Engineer 8



Sept. 13 -17, 2004

• Reflection by the soil

ie //ˆ

ik e

nieˆ

reˆ

ieˆ

reˆ

rk

OUTDOOR/INDOOR RADIO PROPAGATION



Sept. 13 -17, 2004

ie //ˆ

ik

en

ieˆ

ieˆ

ieˆ

ieˆ

teˆ

teˆtkreˆ

reˆrk

i

i

r

r

E

ER

E

E

////i

iloc

r

r

E

ER

E

E

i

i

t

t

E

ET

E

E

Geometrical and Physical Model for indoor/outdoor Theoretical Multilayer dielectric model : (3 layers) Patched wall model : (percentage of windows area in the wall) Reflection/transmission matrix: full polarimetric description Efficient Image Source Coordinates Calculation.

The new innovative features of the propagation model IMPLEMENTED IN THE PREDICTION TOOL:

/ /,R / /,T

wd

ir

t

w i




Sept. 13 -17, 2004

Patched wall model • The main walls of the buildings are

composed of different materials.

• It is necessary to introduce patches of different dielectric constants and physical sizes to represent actual objects.

• Two different patches may be used: concrete wall and glass.

k

i iik

i i

k

i ii TsS

TST

1

1

1

k

i iik

i i

k

i ii RsS

RSR

1

1

1

where:− Si : size coefficients for object− Ri , Ti : reflection and transmission

coefficients, respectively, for the i-th object

− 100*si is the percentage of object area in the wall.




Sept. 13 -17, 2004

• Commercial plate of glass - standardized thicknesses:1,5 -1,8 mm / 2,5 mm / 3,5 - 4 mm / 4-6 mm / 6-12 mm

Material ’r ’’r [S/m]Frequency

[GHz]

Glass 3.8 - 8 0.003 3

Wood 1.5 - 2.1 0.07 3

Dry Brick 4 - 4.5 0.05- 0.1 3 - 4

Dry Concrete

4 - 6 0.1 - 0.3 3 - 60

Aerated Concrete

2-3 0.1 - 0.5 3 - 60

Limestone 7 - 7.5 0.03

Marble 11.6

Ground 7 - 30 0.001 – 0.03

• Dielectric constants and conductivity for same common materials




Sept. 13 -17, 2004

Transmission and reflection coefficients




Sept. 13 -17, 2004

Building Parameter

Wall permittivity (complex): w

Wall thickness : dw

Percentage of windows area in the wall : s

Indoor specific attenuation factor : b

ray launching approach

Reflection/Transmission

Operation procedure


Change of polarization representation frame : Local impact frame -> Ray fixed frame**.

BRBR loc 1

),,,(//,//,

w

iiw

dRR

i

i

r

r

E

ER

E

E

//0

0

R

RR loc

POLARIMETRIC REFLECTION

Theoretical Multilayer dielectric model

**The matrix B perform a rotation through a suitable angle



Sept. 13 -17, 2004

VERTICAL SCAN

The beam of the source is scanned. To generate virtual secondary sources, it is analyzed in iterative manner the basic structure Soil/Wall/Roof of each building in the beam.

On each floor level, for each output grid’s pixel of indoor coverage map the optical-ray transmitted through the illuminated wall is evaluated.




Sept. 13 -17, 2004


/ /,R / /,T

wd

ir

t

w iFeatures of the propagation model

Geometrical and Physical Model for indoor/outdoor

Theoretical Multilayer dielectric model: (3 layers) Patched wall model : (percentage of windows area

in the wall) Geometric-optical (GO) Reflected and Transmitted

rays : full polarimetric description Efficient Image Source Coordinates Calculation. Consider waveguiding effects, such as wave guiding

in corridors (canyoning) Penetration of radiowaves into buildings: outdoor-

to-indoor propagation. Indoor Ray launching approach : estimate of the

indoor coverage (at each floor level) is taken into account : 3D field computation

Higher indoor field computational efficiency



Sept. 13 -17, 2004

Output/Indoor fields



Sept. 13 -17, 2004

Resources – Outdoor/IndoorMan power in months

Academy

Professor 4

Researcher 2

Ph.D.Student

Graduate Student 2

Industry

Senior Engineer

Engineer

Junior Engineer 12



Sept. 13 -17, 2004

New York University University of Naples

Reflections

(dielectric walls)YES YES

Diffraction by vertical edges

YES YES

Diffraction by horizontal edges

YES YES

Stop criteriaAfter a fixed number of reflections/diffractions

When the field is under a fixed threshold

Diffraction coefficientPerfectly conducting or

perfectly absorbing walls Dielectric walls

Outdoor-indoorNO, or a single field value

per buildingYES (field values at different

floors)

VPL PROF. BERTONI VS.

VPL UNIVERSITY OF NAPLES



Sept. 13 -17, 2004

EXISTING CELL PLANNERS

Companies and Programs

Agilent Wizard Wireless Network Planning and Design Tool

Citec WinErt

AWE Communications WinProp

Forsk Atoll

Aircom Assett

HNIT Baltic Cellular Expert

TILab Vigila

Nokia NetAct Planner

Marconi deciBel Planner



Sept. 13 -17, 2004

Validation



Sept. 13 -17, 2004

Validation - Evaluation



Sept. 13 -17, 2004

Validation -Measurements



Sept. 13 -17, 2004

Deterministic approach



Sept. 13 -17, 2004

Napoli – Piazza del Plebiscito



Sept. 13 -17, 2004




Sept. 13 -17, 2004

Caltanissetta – Piazza Roma



Sept. 13 -17, 2004




Sept. 13 -17, 2004

Napoli - Piazza Nazionale



Sept. 13 -17, 2004




Sept. 13 -17, 2004

Napoli - Quartieri Spagnoli



Sept. 13 -17, 2004




Sept. 13 -17, 2004

What can I do with the electromagnetic field prediction?

• Increase SNR• Increase channel capacity• Reduce the cost for bandwith• Reduce biological effects



Sept. 13 -17, 2004

Is there any other problem that can be solve?

• GSM planning• UMTS multipath• Mobile• WLAN• Indoor

numerical and graphical solvers for urban propagation capri wireless school sept. 13 -17, 2004 1/116...

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