Project IEEE 802 15 Working Group for Wireless

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Project: IEEE 802. 15 Working Group for Wireless Personal Area Networks (WPANs) March 2004

Project: IEEE 802. 15 Working Group for Wireless Personal Area Networks (WPANs) March 2004 doc. : IEEE 802. 15 -04/120 r 0 Submission Title: [Body area channel modeling for IEEE 802. 15. 4 a] Date Submitted: [11 Mar 2004] Source: [Andrew Fort, Julien Ryckaert, Bert Gyselinckx] Company [IMEC] Address [Kapeldreef 75, Leuven, Belgium 3001] Voice: [+32(0)16 28 12 11], FAX: [+32(0)16 22 94 00], E-Mail: [andrew. fort@imec. be] Re: [Channel model for communication around the body] Abstract: [Channel model for communication around the body] Purpose: [Contribute to channel modeling for body area applications] Notice: This document has been prepared to assist the IEEE 802. 15. It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein. Release: The contributor acknowledges and accepts that this contribution becomes the property of IEEE and may be made publicly available by 802. 15. Submission 1 Bert Gyselinckx, IMEC

March 2004 doc. : IEEE 802. 15 -04/120 r 0 Outline • • Goal

March 2004 doc. : IEEE 802. 15 -04/120 r 0 Outline • • Goal of our channel model Simulation results Proposed channel model Link Budget Submission 2 Bert Gyselinckx, IMEC

March 2004 doc. : IEEE 802. 15 -04/120 r 0 Goal Channel model •

March 2004 doc. : IEEE 802. 15 -04/120 r 0 Goal Channel model • Determine required transmit power for a target BER as a function of the antenna position on the body, and the distance to walls or obstacles. Submission 3 Bert Gyselinckx, IMEC

March 2004 doc. : IEEE 802. 15 -04/120 r 0 Propagation around the body

March 2004 doc. : IEEE 802. 15 -04/120 r 0 Propagation around the body through creeping wave EM waves propagate around the body via two paths: – Penetration (dielectric losses, tissues interfaces losses) – Creeping waves (diffraction mechanism) Time step 181 REMCOM XFDTD software together with a complete body model: 1 time step = 10 ps Submission 4 Bert Gyselinckx, IMEC

March 2004 doc. : IEEE 802. 15 -04/120 r 0 We determined the path

March 2004 doc. : IEEE 802. 15 -04/120 r 0 We determined the path loss near the human body by simulation. • • Submission Exponential decay with angle difference Height difference less important Path loss is higher for higher frequencies Variance is larger in the interference region 5 Bert Gyselinckx, IMEC

March 2004 doc. : IEEE 802. 15 -04/120 r 0 Model with exponentially decaying

March 2004 doc. : IEEE 802. 15 -04/120 r 0 Model with exponentially decaying loss Breakpoint angle: Interferences between the clockwise wave, the counterclockwise wave and the penetrating wave Creeping wave propagation at 900 MHz Submission Lower decay factor but larger variations 6 Bert Gyselinckx, IMEC

March 2004 doc. : IEEE 802. 15 -04/120 r 0 We propose a Rician

March 2004 doc. : IEEE 802. 15 -04/120 r 0 We propose a Rician Model to simulate nearby walls and obstacles Specular Component Scattered Components • Based on Rician “line of sight” channel model. • The variance and attenuation of creeping wave << reflected paths. • Ratio of Specular (Line of sight) power and Scattered (reflected power) must be estimated. Submission 7 Bert Gyselinckx, IMEC

March 2004 doc. : IEEE 802. 15 -04/120 r 0 The specular and scattered

March 2004 doc. : IEEE 802. 15 -04/120 r 0 The specular and scattered component powers can be estimated • Specular component power can be estimated based on our simulated results. • Scattered component power can be estimated based on the classical exponential path loss model: Path loss exponent 2 Path loss at reference distance (do) Distance traveled by scattered components Reference distance (1 meter) Parameters to be confirmed with simulations Submission 8 Bert Gyselinckx, IMEC

March 2004 doc. : IEEE 802. 15 -04/120 r 0 Rician Factor can now

March 2004 doc. : IEEE 802. 15 -04/120 r 0 Rician Factor can now be estimated as a function of distance to obstacles • • • Rician factor increases as we move further from obstacles Rician factor decreases with increasing carrier frequency Rician factor decreases with increasing angle separation Submission 9 Bert Gyselinckx, IMEC

March 2004 doc. : IEEE 802. 15 -04/120 r 0 Required Transmit Power (d.

March 2004 doc. : IEEE 802. 15 -04/120 r 0 Required Transmit Power (d. Bm) Link Budget : Best case occurs either very far or very close to obstacles. Scattered components dominates K << 0 d. B Submission Target BER = 10 -5 BPSK 900 MHz Scattered components begin to interfere with creeping wave. 10 Creeping wave dominates K >> 0 d. B Bert Gyselinckx, IMEC

March 2004 doc. : IEEE 802. 15 -04/120 r 0 Conclusions • Creeping waves

March 2004 doc. : IEEE 802. 15 -04/120 r 0 Conclusions • Creeping waves are a significant propagation mechanism affecting communication around the body. • Reflected signal component from walls and obstacles in an indoor environment influence the required transmit power. • We propose using a Rician model to perform a link budget as a function of antenna separation on the body and distance from obstacles. Submission 11 Bert Gyselinckx, IMEC

March 2004 doc. : IEEE 802. 15 -04/120 r 0 Future Work • Improve

March 2004 doc. : IEEE 802. 15 -04/120 r 0 Future Work • Improve estimates of P 0 and Pq 0 for different antennas. • Estimation of path loss exponent for different room geometries. • Simulations to justify the Rician channel model and to compare with other distributions. • UWB channel modeling. Submission 12 Bert Gyselinckx, IMEC