RadioTechnology LabSeoul National University

[ ]The Modeling of User Body Shadowing based on the UTD

Radio Technology Lab (prof. C.H. Kim)

Kim Changhoe

INDEX

1. Introduction

2. UTD Model

3. Experiment Model

4. Result of UTD & Experiment Model

5. Conclusion

RadioTechnology Lab

Seoul National University

RadioTechnology Lab

Seoul National University

RT

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adioechnology

aboratory1. Introduction (1/2)

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Shadowing Effect Shadowing effect means the phenomenon that obstacle including building or

mountain attenuates the received signal power

Important when we model the channel

Human & wave propagation Human is the nearest obstacle of the mobile (receiver)

Human can disturb wave propagation in indoor environment

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aboratory1. Introduction – Problem set (2/2)

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What is the Problem ? Shadowing effect by user (specially, in a indoor environment)

Reflection, diffraction should be considered

How can We Solve ?

UTD Exact calculation

Body shadowing

effect

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aboratory2. UTD Model (1/4)

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UTD (Uniform Geometrical Theory of Diffraction)Effective method for analyzing diffraction of material

We can obtain numerical analysis values

Three types of diffraction situation (Scattering, Radiation, Coupling)

Scattering Radiation Coupling

Stick to

materialX Only Rx or Tx Tx & Rx

Concept

Figure

Tx

Rx

material

TxRx

TxRx

material material

Model

Contents

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aboratory2. UTD Model (2/4)

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Lit Zone LOS(Line-of-Sight) component

Dependent on the distance mainly

Shadow ZoneNLOS(non-LOS) component

Including the distance, material and diffraction effect should be involved

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aboratory2. UTD Model – Scattering (3/4)

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When Rx is in Lit zone,

𝑬𝟎 = E-field of LOS component

R = UTD reflection coefficient, L = distance coefficient

When Rx is in Shadow zone,

E1, E2 = E field at Q1’, Q2’ respectively

T1, T2 = UTD diffraction coefficient (Q1’-Q1, Q2’-Q2)

𝑬𝑺,𝑳𝑶𝑺 = 𝑬𝟎𝑹𝑳𝒅𝒆−𝒋𝒌𝒔𝑺𝟏 + 𝑬𝟎

𝑬𝑺,𝑵𝑳𝑶𝑺 = 𝑬𝟏𝑻𝟏𝒆−𝒋𝒌𝒔𝑺𝟐

√𝒔𝑺𝟐+ 𝑬𝟐𝑻𝟐

𝒆−𝒋𝒌𝒔𝑺𝟑

√𝒔𝑺𝟑

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aboratory2. UTD Model – Radiation (4/4)

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When Rx is in Lit zone,

𝑯𝟏 = Radiaton Coefficient in Lit zone

𝑪𝟎 = propotional factor, 𝜽𝒍 = angle between LOS line and normal line of Rx

When Rx is in Shadow zone,

𝑯𝟐=Radiation coefficient in Shadow zone

𝑡1, 𝑡2= arc length respectively Q3-Rx and Q4-Rx

𝑬𝑹,𝑳𝑶𝑺 = 𝑪𝟎𝑯𝟏 𝒄𝒐𝒔𝜽𝒍𝒆−𝒋𝒌𝒔𝑹𝟏

√𝒔𝑹𝟏

𝑬𝑹,𝑵𝑳𝑶𝑺 = 𝑪𝟎𝑯𝟐[𝒆−𝒋𝒌𝒕𝟏

𝒆−𝒋𝒌𝒔𝑹𝟐

𝒔𝑹𝟐+𝒆−𝒋𝒌𝒕𝟐

𝒆−𝒋𝒌𝒔𝑹𝟑

𝒔𝑹𝟑]

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aboratory3. Experiment Model

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Experiment Model The power of received signal is measured

Rx moved from 𝜽 = 𝟎° to 𝜽 = 𝟑𝟔𝟎° at intervals of 10°

Frequency of the signal is 2.4GHz

Chest

Model

Head

Model

Rx-User

(d)15cm 2cm

Antenna

Height

(Rx)

140cm 170cm

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aboratory4. Result – Chest Model (1/2)

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Received PowerMeasurement pattern is similar with the scattering model

Scattering model and data dependent on LOS and reflection component from 𝜽 = 𝟎° to SSB angle

Deep fades exist

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aboratory4. Result – Head Model (2/2)

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Received PowerAlso similar pattern with Scattering Model

Scattering Model and data dependent on LOS and reflection component from 𝜽 = 𝟎° to SSB

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aboratory5. Conclusion

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UTD SimulationUser shadowing effect can be solved by UTD Scattering or Radiation

Model

Experiment data is similar with Scattering model for chest model and head model the pattern of received power

Future WorkExperiments based on the motion of user

Another band frequency (for indoor)

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aboratoryReference

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[1] Kim Changhoe, Jung jaehoon, Kim Seongchul, “A Study on the Modeling of User Body Shadowing based on the UTD”, in Proc. KICS Int, Conf Commun, Jeju, Korea, June, 2014

[2] J. H. Jung, J. H. Choi, Y.H. Kim and C.H. Kim, “A Study on the User-Shadowing based on the Ray-tracing”, in Proc. KICS Int, Conf Commun, pp. 247-248, Pyeongchang, Korea, Jan, 2014

[3] D.A. Mcnamara, C.W. Pistorius, and J.A. Malherbe, “Introduction to the Uniform Geometrical Theory of Diffraction”, Boston, MA: Artech House, 1990.