COST 286Electromagnetic Compatibility

(EMC) in Diffused Communication Systems

Hamburg, 25th-26th November, 2004

Wroclaw University of TechnologyInstitute of Telecommunications and AcousticsWybrzeże Wyspiańskiego 27, 50-370 Wrocław

Polande-mail: kamil.staniec@pwr.wroc.pl

Research on simulating radiowave propagation in closed environments

Kamil Staniec

Technological congestion

1/211/21

2.4 2.4835 5.15 - 5.255.25 - 5.35

5.725-5.725

U-NIIISMLow Middle High

IEEE 802.11bIEEE 802.11g

HomeRFBluetooth

SRD’sZigBee

ENG/OB

HyperLAN 1/2IEEE 802.11a

Co

mm

un

icat

ion

syst

ems

No

n-c

om

mu

nic

atio

nap

plic

atio

ns

[GHz]

RFIDMilitary

DomesticSulphur plasma lighting

1. 802.11b - 802.11g (interference)2. 802.11a - 802.11b/g (no interference)3. Bluetooth - 802.11b/g (interference)

Current measurements – mixed configurations

Interferingsession

AP1

obstacle

distance_1

Monitor

U2 AP2

U1

Test session

2/212/21

Existing indoor propagation models

1. Statistical models:

1.1 Amplitude distribution

1.2 Phase distribution

1.3 Angle-of-arrival distribution

2. Empirical models

2.1 ITU-R P.1238:

2.2 Multilayer model:

28)(loglog20 nLdNfL f

FAFAFDDnDPLLk

k )/log(10)( 00

FAF = 15+(510)*k [dB] 3/213/21

Indoor propagation effects

4/214/21

OUTER WALL

PARTITIONWALL

BUILDINGINTERIOR

FLOOR

TX

Transmission

Tun

nelin

gReflection

Scattering

Diffraction

FURNITURE

[modified 3]

1)(

0

)()]([)(),(

N

k

tjkk

kettath

k-th path{ak, tk, k}

t

{ak1, k1}

{ak2, k2}

{akn, kn}

tk1

tk2

tkn

Multipath propagation

5/215/21

Advantages of using ray tracing method:imitates radiowave propagation

Tx

Rx1Rx2

k

dj

kij

jim

miritiDi

i eTDGGddL

PZE

200 )()()(

)(4

6/216/21

7/217/21

patterns drawn with 642 rays

Advantages of using ray tracing method:easy generation of any antenna patterns

P

s

m

rms

0.1 0.2 0.3 0.4 0.5 0.6 0.7

Pi

8/218/21

Advantages of using ray tracing method:radio channel power delay time profile

Indoor propagation – challenges to be solved

Common assumptions in existing RT model:

• constant wall attentuation (irrespective of material electric parameters)

• walls/partitions perfectly thin

• presence of objects/persons not considered

9/219/21

Research – our objectives

Create exact analytical model that includes:

• persons/objects

• „thick” walls

• variable attenuation of partitions

• radio channel time-dispersion characteristics

10/2110/21

15 mm

15 mm

120 mm

120 mm

100 mm

CONCRETE

CONCRETE

BRICK

BRICK

MINERAL WOOL

X-section of a partition wall

11/2111/21

Multilayer structure – influence of innacurate electric parameters

12/2112/21

Pol H

Pol V

Multilayer structure – wall attenuation vs. incidence angle

13/2113/21

Light concrete 15 mm

Light concrete 15 mm

Brick 120 mm

Mineral wool 100 mm

Brick 120 mmPol H

Pol V

Multilayer structure – EM wave attenuation vs. frequency

14/2114/21

Infinite thinness Actual thickness

Thick / thin walls modeling

15/2115/21

11

2

12

d1 d2

0 0

0 011

22

i

r

t

1

2

Analytical calculation of multilayer wall attenuation

16/2116/21

Thick walls with persons (yellow) and objects (green) 17/2117/21

Simulated environment (example)

Optimisation 1:Environment prescanning

Tx

VISIBLE ITEMS

INVISIBLE ITEMS

18/2118/21

Rv=0,425

Av=34,581 dB

Look-up table

Inc. angle=10o

Optimisation 2:look-up table in variable attenuation calculations

19/2119/21

• Environment database preprocessing accomplished:• available modes:

• perfectly thin walls

• actually thick walls

• inclusion of persons

• inclusion of furniture

• variable walls attenuation w/r to frequency, incidence angle, polarization (database storage)

• Preliminary ray tracing for „full” ray tracing optimisation purposes (av. 95% time saving)

20/2120/21

State of research:

• e-field distribution maps in a closed environment (SOHO, vehicles, railway tunnels)

• information on radio channel dispersiveness - Power Delay Profile /available for each pixel/

• modeling mutual AP’s interference

21/2121/21

Possible applications:

THANK YOUTHANK YOU