ULTRA WIDE BAND TECHNOLOGY BODY AREA NETWORKS BW ³ 500 MHz regardless of fractional BW UWB is a form of extremely wide spread spectrum where RF energy is spread over gigahertz of spectrum Wider than any narrowband system by orders of magnitude Power seen by a narrowband system is a fraction of the total UWB power UWB signals can be designed to look like imperceptible random noise to conventional radios

1. Low Power
UWB
Technology
for WBAN

2. 2
What is Ultra Wide Band ?
• UWB transmitter signal BW:
‘OR’
• BW ≥ 500 MHz regardless of fractional BW
fu-fl
fu+fl
2 ≥ 0.20
Where:
fu= upper 10 dB down point
fl = lower 10 dB down point
Source: US 47 CFR Part15 Ultra-Wideband Operations FCC Report and Order, 22 April 2002:
http://www.fcc.gov/Bureaus/Engineering_Technology/Orders/2002/fcc02048.pdf

3. UWB: Large Fractional Bandwidth
PowerSpectralDensity(dB)
one “chip”one “chip”
CDMA: 1.288Mcps/1.8 GHz
0.07% bandwidth
6% bandwidth
-80
-40
0
Frequency (GHz)
3 6 9 12 15
Random noise signal
100% bandwidth
UWBUWB
NBNB
20% bandwidth

4. Relative Bandwidth
• UWB is a form of extremely wide spread spectrum where RF
energy is spread over gigahertz of spectrum
– Wider than any narrowband system by orders of
magnitude
– Power seen by a narrowband system is a fraction of the
total UWB power
– UWB signals can be designed to look like imperceptible
Narrowband (30kHz)
Wideband CDMA (5 MHz)
UWB (Several GHz)
Frequency
Part 15 Limit
( -41.3dBm/Hz )

5. UWB Signal Characteristics
7,500 MHz available spectrum for unlicensed use
US operating frequency: 3,100 – 10,600 MHz
Emission limit: -41.3dBm/MHz EIRP
Indoor and handheld systems
UWB signal transmitter defined as having the lesser of
Fractional bandwidth greater than 20%
Occupies more than 500 MHz
UWB is NOT defined in terms of
Modulation
or Carrierless
or Impulse radio

6. FCC First Report and Order
Authorizes Five Types of Devices
Class / Application Frequency Band for Operation at
Part 15 Limits
User
Limitations
Communications and
Measurement Systems
3.1 to 10.6 GHz
(different “out-of-band” emission
limits for indoor and hand-held
devices)
No
Imaging: Ground
Penetrating Radar, Wall,
Medical Imaging
<960 MHz or 3.1 to 10.6 GHz Yes
Imaging: Through-wall <960 MHz or 1.99 to 10.6 GHz Yes
Imaging: Surveillance 1.99 to 10.6 GHz Yes
Vehicular 22 to 29 GHz No

7. Effectiveness of Ultra Wide Band
• Shannon showed that the system capacity, C, of a channel perturbed
by AWGN ---
)1(log2
N
S
BC +=
Where:
C = Max Channel Capacity (bits/sec)
B = Channel Bandwidth (Hz)
S = Signal Power (watts)
N = Noise Power (watts)
Capacity per channel (bps) ∝ B
Capacity per channel (bps) ∝ log(1+S/N)
1. Increase B
2. Increase S/N, use higher order modulation
3. Increase number of channels using spatial separation (e.g., MIMO)
What if I do not
require a high
capacity ?

8. UWB
-5db 5 db 10 db 15 db
1
2
3
4
1/2
1/4
1/8
1/16
Bits/sec/Hz
Eb/N
0
Bandwidth LimitedEnergy Limited
UWB Usual goal
Low signal to noise ratio
Bandwidth inefficient

9. 4G
POTENTIAL FOR UWB
3G and beyond

10. UWB Properties
• Extremely difficult to detect by unintended users
– Highly Secured
• Non-interfering to other communication systems
– It appears like noise for other systems
• Both Line of Sight and non-Line of Sight operation
– Can pass through walls and doors
• High multipath immunity
• Common architecture for communications, radar &
positioning (software re-definable)
• Low cost, low power, nearly all-digital and single chip
architecture

11. UWB Emission Limits for GPRs, Wall
Imaging, & Medical Imaging Systems
Operation is limited
to law enforcement,
fire and rescue
organizations,
scientific research
institutions,
commercial mining
companies, and
construction
companies.
0.96 1.61
1.99
3.1 10.6
GPS
Band
Source: www.fcc.gov

12. UWB Emission Limits for Thru-wall
Imaging & Surveillance Systems
Operation is limited
to law enforcement,
fire and rescue
organizations.
Surveillance
systems may also be
operated by public
utilities and
industrial entities.
0.96 1.61
1.99 10.6
GPS
Band
Source: www.fcc.gov

13. UWB Emission Limit for
Indoor Systems
0.96 1.61
1.99
3.1 10.6
GPS
Band
Source: www.fcc.gov

14. 0.96 1.61
1.99
3.1 10.6
GPS
Band
Source: www.fcc.gov
UWB Emission Limit for
Outdoor Systems
Proposed in
preliminary Report and
Order,
Feb. 14, 2002.

15. First Report and Order, April 22, 2002.
0.01 0.1 1 10 100
-80
-70
-60
-50
Frequency, GHz
-40
EIRP, dBm/MHz
UWB Band-
width must be
contained
here
Actual UWB Emission Limit for
Hand-held Systems

16. Range Vs Data Rate
Thursday, August 21, 2014
Dr. M.MEENAKSHI, DECE, CEG,
ANNA UNIVERSITY
16

17. Wireless Body Area Network

18. WBAN Scenario

19. WIRELESS ACCESS
POINT
(PCF MODE)
UWB
TRANSCEIVER
SERVER
WIRELESS ACCESS
POINT
(PCF MODE)
UWB
TRANSCEIVER
WIRELESS ACCESS
POINT
(PCF MODE)
UWB
TRANSCEIVER
WIRELESS ACCESS
POINT
(PCF MODE)
UWB
TRANSCEIVER
WIRELESS ACCESS
POINT
(PCF MODE)
UWB
TRANSCEIVER
DATA
BASE
CLOUD
ALARM TO
APPROPRIATE
PERSONNEL
UWB
TR.
PROPOSED NETWORK ARCHITECTURE FOR PUBLIC HOSPITALS

20. WBAN Challenges

21. Requirements for WBAN
• Non-invasive/ remote operation
• Bio-compatibility and biological/environment friendliness
• Human safety (Low RF emission power)
– Limited Specific Absorption Rate (SAR)
• Low power Consumption
• Scalability for data rate
–10Kbps(low data) ~10Mbps(raw data)
• Range (say upto 3 meters)
• Satisfying spectrum regulatory issues

22. Technologies for WBAN
Thursday, August 21, 2014
Dr. M.MEENAKSHI, DECE, CEG,
ANNA UNIVERSITY
22

23. Comparison with other technologies for
WSN

24. Why UWB for WBAN ?
• Bluetooth (802.15.1)  cable replacement technology, no support for multi-
hop communication, complex protocol stack, high energy consumption
• ZigBee (802.15.4)  energy consumption is higher, interference mitigation is
difficult, poor multipath performance, however less complex and cost effective

25. UWB Characteristics suited to WBAN
• Penetration through obstacles
• High precision ranging at the cm level
• Low electromagnetic radiation
• Low processing energy consumption
• Low Interference
• Security requirements – data confidentiality,
authenticity, integrity, freshness

26. WBAN Channels
Thursday, August 21, 2014
Dr. M.MEENAKSHI, DECE, CEG,
ANNA UNIVERSITY
26

27. In-body WBAN Channel Model
• 30-35 dB additional loss over free space loss
• Path loss exponent ~ between 3 and 4
(depending on the body part considered)
• Antenna height / distance also impacts loss
• Loss 20 dB more at 5mm compared to at 5 cm

28. Extra-body WBAN Channel Model
• LoS / NLoS
• Path loss exponent ~ between 5 and 6
(depending on the body part considered)
• NLoS loss more than LoS loss
– Diffraction around the human body
– Absorption of large amount of radiation by the
body
• Movement of limbs could cause loss > 30 dB

29. UWB Transmitter
Pulse
Generation
Modulate
Data in
Pulse
Generator
LNA Detector Data out
Simplified System; looking at pulse only
MF
)(tu( )ts
Pulse shaping
filter
Matched Filter
•A UWB system uses a long sequence of pulses for communication.
•A regular pulse train produces energy spikes (comb-lines) at regular intervals.
•Pulse train carries no information and “comb-lines” interfere with conventional radios.
Frequency (GHz)
-50
-40
-30
-20
-10
0
0 1 2 3 4 5
Time
Pulse train

30. Data Modulation
 Pulse Position Modulation
(PPM)
 Pulse Amplitude Modulation
(PAM)
 On-Off Keying (OOK)
 Bi-Phase Modulation (BPSK)

31. UWB Transmitter
•UWB Impulse systems use pulse position modulation (PPM)
•The PPM modulates the position of a pulse about a nominal
position. A “1” and a “0” is determined by a pico-second delay
T1 or T2 of a mono-pulse.
•PPM “smooths-out” the spectrum making the transmitted look
almost like noise.
•The Pseudo-Random noise coding makes the spectrum appear
very-much like noise.
•Only a receiver with the same PN-code template can decode
the pulse transmission.

32. 32
Frequency (GHz)
-50
-40
-30
-20
-10
0
0 1 2 3 4 5
Time
Pulse train
Frequency (GHz)
-50
-40
-30
-20
-10
0
0 1 2 3 4 5
T1
T2
Time
Frequency (GHz)
-50
-40
-30
-20
-10
0
0 1 2 3 4 5
Time
hopping
Nominal
pulse train
New position
after hopping

33. TH-PPM UWB
Tf
Ts : data symbol time
Tc t
pulse wtr(t)
Str(t)
cfchf
s
fsfss
ph
TTeiTNT
N
TTeiTNT
NNC
⋅=⋅≥
⋅=⋅=
===
3..
symboldataperpulsesofnumber:
4..
4periodcode,2,]2001[codeword
=0id
Tf
Ts
Tc t
δδδδ
Str(t)
=1id

34. Monocycle Shapes for UWB
• Monocycle shapes will affect the performance
– Gaussian pulse
– Gaussian Monocycle
– Scholtz’s Monocycle
– Manchester Monocycle
– RZ- Manchester Monocycle
– Sine Monocycle
– Rectangle Monocycle

35. Monocycle Shapes for UWB (cont.)
• Gaussian Pulse • Gaussian monocycle
– first derivative of Gaussian pulse

36. Monocycle Shapes for UWB (cont.)
• Scholtz’s monocycle
- second derivative of Gaussian pulse
• Manchester Monocycle

37. Monocycle Shapes for UWB (cont.)
• RZ- Manchester Monocycle • Sine Monocycle

38. Monocycle Shapes for UWB (cont.)
• Rectangle Monocycle

39. UWB Receiver
Pulse
Generation
Modulate
Data in
Pulse
Generator
LNA Detector Data out
Simplified System; looking at pulse only
MF
)(tu( )ts
Pulse shaping
filter
Matched Filter
Autocorrelation of binary
transmission

40. 40
UWB versus Traditional Narrow Band Transceiver

41. All Digital UWB Radio
Conventional Integrated Narrowband Transceiver:
UWB “Mostly Digital” Radio:
D/A
I
QMIXERLNA
PA
A/D
A/D
DIGITAL:
F SYNTH
ANALOG:
MIXER
D/A
D/A
I
LNA
PA
A/D
DIGITAL:
ANALOG:
• Simplicity
• Low Cost
• Integration
• Low Power
• Large BW
• Ranging
• Unlicensed
Operation
• Coexistence
UWB Promises:

42. Pulse Reception
Thursday, August 21, 2014
Dr. M.MEENAKSHI, DECE, CEG,
ANNA UNIVERSITY
42
time
time
Sample Time
Pulse
Reception
Window
Pulse Transmission Rate
Voltage
Receiver
Operation
Analog On
Sampling On
Digital Off
Analog Off
Sampling Off
Digital On
Analog Off
Sampling Off
Digital Off
Analog On
Sampling On
Digital Off
Only process data from a window of time:

43. Power Conservation
Thursday, August 21, 2014
Dr. M.MEENAKSHI, DECE, CEG,
ANNA UNIVERSITY
43
Duty-Cycled
To ~1mW
(1 Mpulse/s)
Always On
~8 mW
(32 Mpulse/s)
TX DLL
CONTROL
GAIN
A/D
DIGITAL
OSC
BIAS
Duty-Cycling
Starts

44. 44
UWB Advantages - Limitations
• UWB radio systems have large bandwidth (> 1 GHz).
• UWB has potential to address today’s “spectrum
drought”.
• Emissions below conventional level.
• Single technology with 3 distinct capabilities.
• Secure transmission, low probability of interception or
detection and anti-jam immunity.
• Not appropriate for a WAN (Wide Area Network)
deployment such as wireless broadband access.
• UWB devices are power limited.