1. doc.: IEEE 802.15-04/0249r0 Submission May 2004 Bart Van Poucke, IMECSlide 1 Project: IEEE 802.15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: [Body area channel modeling update ] Date Submitted: [11May2004] Source: [Bart Van Poucke] Company [IMEC] Address [Kapeldreef 75, Leuven, Belgium 3001] Voice:[+32(0)16 28 12 11], FAX: [+32(0)16 22 94 00], E-Mail:[vanpouck@imec.be] Re: [Channel model proposal] Abstract:[Update on channel model for communication around the body] Purpose:[Contribute to low power air-interface definition 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.

2. doc.: IEEE 802.15-04/0249r0 Submission May 2004 Bart Van Poucke, IMECSlide 2 Outline Body area UWB channel modeling strategy Simulation results so far Conclusion and Future work

3. doc.: IEEE 802.15-04/0249r0 Submission May 2004 Bart Van Poucke, IMECSlide 3 Body area channel consists of a creeping wave and scattered components. Creeping wave results from waves diffracting around the body This received signal is the creeping wave combined with reflections off of nearby obstacles. Creping wave Component Scattered Components

4. doc.: IEEE 802.15-04/0249r0 Submission May 2004 Bart Van Poucke, IMECSlide 4 We focus only on UWB communication around the human body. We DO: –Develop a channel model only for waves diffracting around the body –Use the Remcom FDTD simulator. We EXPECT: –To incorporate waves reflecting off of nearby walls and obstacles, by combining our results with other measurements made by the channel modeling study group: Consider our channel model as a distinct cluster arriving earlier than other clusters. For LOS models: replace the LOS component with the creeping wave component in our model.

5. doc.: IEEE 802.15-04/0249r0 Submission May 2004 Bart Van Poucke, IMECSlide 5 Waves travel through and around the body. EM waves propagate around the body via two paths: –Penetration (dielectric losses, tissues interfaces losses) –Creeping waves (diffraction mechanism) REMCOM XFDTD software together with a complete body model: 1 time step = 10ps Time step 01 Time step 11 Time step 21 Time step 31 Time step 41 Time step 51 Time step 61 Time step 71 Time step 81 Time step 91 Time step 101 Time step 111 Time step 121 Time step 131 Time step 141 Time step 151 Time step 161 Time step 171 Time step 181

6. doc.: IEEE 802.15-04/0249r0 Submission May 2004 Bart Van Poucke, IMECSlide 6 We recorded the electric field around the body for an UWB pulse Transmitted a 100 ps pulse using a simple 1.5 cm dipole antenna. The resulting pulse at a reference position 20 degrees from antenna was approximately a 1 ns Gaussian pulse centered at 4 GHz. All measurements made relative to this reference position. Time step 11

7. doc.: IEEE 802.15-04/0249r0 Submission May 2004 Bart Van Poucke, IMECSlide 7 Path loss depends on angle separation between antennas

8. doc.: IEEE 802.15-04/0249r0 Submission May 2004 Bart Van Poucke, IMECSlide 8 Pulse is severely distorted by the human body. 90 Degree separation (with body) Same position (free space) Time Magnitude

9. doc.: IEEE 802.15-04/0249r0 Submission May 2004 Bart Van Poucke, IMECSlide 9 Status and Conclusions We are simulating UWB communication around the body using the Remcom FDTD simulator. We propose re-using measurements done by this study group to incorporate the influence of surrounding walls and objects. We are currently analyzing the results of our simulations: – We have recorded the path loss around the body – We observed significant pulse distortion

10. doc.: IEEE 802.15-04/0249r0 Submission May 2004 Bart Van Poucke, IMECSlide 10 Future Work Understand underlying mechanism responsible for results. Incorporate simulated results into a statistical model suitable for communication system design and comparison.