1. Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs)
Submission Title: [Channel characterization proposed for Body Area Network]
Date Submitted: [15 January 2008]
Source: [Friedman Tchoffo Talom, Christophe Delaveaud, Julien Keignart, Serge Bories, Laurent Ouvry]
Company: [Laboratory of Electronics and Information Technologies (LETI)]
Address: [CEA-Leti - Minatec, 17 rue des martyrs, Grenoble Cedex 9, FRANCE]
Voice: [ ], FAX: [ ]
Abstract: [This document describes a Channel characterization proposed for Body Area Network (BAN).]
Purpose: [To describe all the elements involved in the channel characterization proposed for Body Area Network (BAN).]
Notice: This document has been prepared to assist the IEEE P 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 P

2. Channel characterization proposed for Body Area Network (BAN)
Friedman Tchoffo Talom, Christophe Delaveaud, Julien Keignart, Serge Bories, Laurent Ouvry
Laboratory of Electronics and Information Technologies (LETI)
France

3. Body surface channel characterization
The specifications of the body surface characterization to be conducted are the following :
Frequency band of interest
Used Antenna
Measurements type (Frequency or Time domain)
Considered environments
Scenario adopted (antenna position)
Parameters extracted from the characterization

4. Frequency band of interest
The characterization will be done on a large frequency band : 400MHz – 6 GHz
For practical reasons, the whole band is subdivided into 3 sub bands.
- Used antennas have to be miniaturized according to the wavelength.
- Design of antennas for all the band (400MHz – 6 GHz) is not very easy.
The following subdivision is adopted :
400 MHz – 1.2 GHz
1.2 GHz – 2.5 GHz
2.5 GHz – 6 GHz

5. Used antennas
In such a characterization, the antennas are key elements.
As there are closed to the body, their characteristics are necessarily modified [1]:
Radiation patterns
Impedance matching
Gain
This has to be clearly understood and considered in the study.
We will specifically address this point in the study by simulation and measurements for all the considered sub bands.

6. Measurements type Frequency domain Characteristics: Drawbacks:
Frequency sweep
Good dynamic
Amplitude and phase are obtained
Only one device  easy calibration
Time domain response obtained using IFFT
Time sweep : ~1 s
Sensitivity : -100 dBm TX
RF Components RX
RF Components
Vector
Network
Analyzer
Port 1
Port 2
Frequency
sweep
Receiver IF
S21 parameter
Drawbacks:
Duration of the measurements
Non stationary Measurements are impossible
Compromise: Resolution & dynamic VS speed
High distance measurement need long RF cable
Post processing

7. Measurements type Time domain Characteristics: Drawbacks:
Generation of very short pulses
Real time measurements
Signal directly in time domain
Used of two instruments (trigged using a cable)
Sensitivity : ~ -50dBm TX
RF Components RX
RF Components
Periodic
Pulse
Generator
Digital
Oscilloscope
Trig.
Drawbacks:
Specific Instruments are needed
Limited measurement dynamic
Narrow band measurement impossible
Post processing
@ Emission
@ Reception
Real time scope
Analog band: 12 GHz
40 Gech/s or
Pulse generator

8. Measurements type Both measurements types will be performed.
Frequency domain measurements:
Scenario with a need of high dynamic
Directly extract path loss value
Time domain measurements:
Simultaneously obtained different scenario characterization
Directly extract delay spread
Evaluate non stationary configuration

9. Considered environments
Four environments are considered :
Anechoic chamber
 No multipath
Indoor office
Contribution of multipath to the link
Indoor corridor
Contribution of multipath to the link
Distribution of multipath different from indoor office case
Anechoic chamber without absorber on the floor
Outdoor like propagation
Contribution of path coming from the floor

10. Adopted scenarios
The scenarios adopted for the measurement are all body surface to body surface (should feed CM3 [1]). B A C E F G D
There are six LOS and NLOS scenarios.
Sc1 : Propagation around the head (A-B)
Sc2 : Propagation from waist to head (E-A/B)
Sc3 : Propagation from waist to torso (E-C)
Sc4 : Propagation from waist to hand (E-F)
Sc5 : Propagation from waist to back (E-D)
Sc6 : Propagation from waist to ankle (E-G)
For all these scenarios, the subjects (~5 persons) will stand up during measurement.

11. Adopted scenarios B A C E F G D
These scenarios are chosen because they represent four meaningful configurations in the BAN context.
Config. 1 : Link with a “coordinator” at the belt
Config. 2 : Link over a short range ( < 1 meter in air)
Config. 3 : Link over medium range ( > 1 meter in air)
Config. 4 : Link affected by non stationarities (hand or feet movements)
Sc1
Sc2
Sc3
Sc4
Sc5
Sc6
Config. 1 X
Config. 2
Config. 3
Config. 4

12. Delay spread parameters :
Parameters extracted from the characterization
Antennas characteristics Effect/
Radiation pattern - Impedance Matching – Gain (use of different antennas and orientations, details TBD)
Path loss parameters:
Friis case:
General case:
Delay spread parameters :
mean excess delay :
RMS delay spread :
: power delay profile for an impulse response

13. Conclusion LETI will perform on body to on body BAN measurements.
Characteristics of the measurements
Band : 400 MHz – 6 GHz
Time and frequency domain
Four environments
only the human body effect on propagation : anechoic chamber
with the effect of the floor : anechoic chamber without absorber on the floor
with channel effects (multipath) : corridor and office
Six scenarios
Various persons : ~ 5 subjects
Parameters extracted
path loss, shadowing
delay spread
(optionally : non stationarity analysis)
The results and models obtained from these measurements will hopefully be available for March or May meetings.

14. Reference
[1] Kamya Yekeh Yazdandoost, “Channel Model for Body Area Network (BAN) ”, IEEE P Working Group for Wireless Personal Area Networks (WPANs), Jan. 2008, doc IEEE P