simplified human body models for interference analysis in ...€¦ · • wireless body area...

Simplified Human Body Models for Interference Analysis in the Cognitive Radio

for Medical Body Area Networks

Łukasz Januszkiewicz

Lodz University of Technology, Institute of Electronics, Poland

Outline:

• Motivation

• Human Body Models

• Simplified body model

• Interference scenario for CR in WBAN

• Computer simulations

• Conclusions

Simplified Human Body Models for Interference Analysis in the Cognitive Radio Simplified Human Body Models for Interference Analysis in the Cognitive Radio 14/04/2014 2

Motivation for the resarch on human body models

Measurements and simulation of:

• Wearable antenna

• Wireless Body Area Network

• Wearable wireless sensors

14/04/2014 Simplified Human Body Models for Interference Analysis in the Cognitive Radio Simplified Human Body Models for Interference Analysis in the Cognitive Radio 3

Human Body Models

Numerical heterogeneous models

• Represent human body tissues which are „sampled” to allow finite difference / finite elements calculation

• Differ with number of tissues and size of elementary cell

• Remcom NMR Hershey

• CST HUGO

• Virtual Population


Human Body Models

Homogenous models used for measurements

• The shape of body is preserved

• Tissues are simulated with a liquid

• SAM – Specific Anthropomorphic Mannequin


Simplified body model

Goals

• Simple physical model that can be easily manufactured (geometry and materials which make it easily to reproduce)

• Comparable values of simulated radio signal attenuation and antenna radiation pattern with heterogeneous model



• The simplified model consist of cylinders.

• Dimensions approximate NMR Hershey model with 6 standard PVC pipes

• Model geometry optimized with XFdtd®

• PCV pipes filled with tissue-simulant liquid



Simplified model was verified by measurements of wearable antenna radiation pattern in 2.4 GHz band


Medical Body Area Networks

• The MWBAN structure:* – Intra- Wireless Body Area Network (Intra-WBAN)

– Inter- Wireless Body Area Network (Inter-WBAN).

*Chavez-Santiago, R.; Nolan, K.E.; Holland, O.; De Nardis, L.; Ferro, J.M.; Barroca, N.; Borges, L.M.; Velez, F.J.; Goncalves, V.; Balasingham, I., "Cognitive radio for medical body area networks using ultra wideband„, Wireless Communications, IEEE , vol.19, no.4, pp.74,81, August 2012


Interference scenario for CR in WBAN

• Cognitive radio in Intra-WBAN, radio channel affected by radio wave attenuation in the body


Interference scenario for CR in WBAN

• Cognitive radio in Inter-WBAN, radio channel affected by on-body antenna radiation pattern


Computer simulations

• UWB antenna model used for simulations


The results of the model validation for Intra-WBAN

• Signal attenuation between transmitter located on the front of the torso and the receiver located on the back



• Signal attenuation between transmitter located on the front of the torso and the receiver located on the left arm



• Signal attenuation between transmitter located on the right arm and the receiver located on the left arm


The results of the model validation for Inter-WBAN

900 MHz 1500 MHz


• On-body antenna radiation pattern simulated with NMR Hershey model and simplified model



2500 MHz 5000 MHz




7500 MHz


Conclusions

• Results obtained with the simplified and the reference model are similar for Intra-WBAN case.

• The signal attenuation simulated for the high attenuation case shows good agreement in several sub-bands (2000MHz ÷ 3000MHz, 4000MHz ÷ 5500MHz)

• In case when different antenna locations are used the results obtained with simplified and reference model are in good agreement.


Conclusions

• The simplified model gives very similar results to the reference model for Inter-WBAN simulations.

• The radiation patterns of UWB antenna located on the body obtained with those models do not differ much in the frequency range from 900 MHz to 7500 MHz.

• The proposed simplified phantom can be suitable for further experimental investigation and testing of CR wireless body area networks.


Thank you.


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