The Future of Wireless Sensor Networks
Kris Pister
Prof. EECS, UC Berkeley
Co-Director, Berkeley Sensor & Actuator Center
(Founder & CTO, Dust Networks)
Outline
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The Past
What Went Wrong
Technology Status
Applications
Technology Directions
BSAC IAB 1997
Autonomous Microsensor Networks with Optical Communication Links
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PI: Kris Pister
Source: Hughes (MICRO)
Funding: $25k, $10k matching, 0% ovhd,
Duration: 1 year
Comments: Collaboration w/ Prof. Joe
Kahn under separate MICRO
BSAC IAB Spring 2000
COTS Dust
GOAL:
• Get our feet wet
RESULT:
• Cheap, easy, off-the-shelf RF systems
• Fantastic interest in cheap, easy, RF:
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–
–
–
Industry
Berkeley Wireless Research Center
Center for the Built Environment (IUCRC)
PC Enabled Toys (Intel)
• Fantastic RF problems
• Optical proof of concept
Berkeley Demos – 2001
Motes dropped from UAV, detect
vehicles, log and report direction
Intel Developers Forum, live demo
800 motes, 8 level dynamic network, and velocity
Seismic testing demo: real-time
data acquisition, $200 vs. $5,000 per
node
vs.
50 temperature sensors for HVAC
deployed in 3 hours. $100 vs. $800
per node.
Cost of Sensor Networks
Mesh Networking
Computing
Power
Installation,
Connection and
Commissioning
$
Sensors
Time
Sensor Networks Take Off!
Industry Analysts Take Off!
800
700
Units (Millions)
600
$8.1B market for
Wireless Sensor
Networks in 2007
500
400
300
Wi-Fi nodes
Handsets
Wireless Sensor Nodes
200
100
0
2003
2004
2005
2006
2007
Source: InStat/MDR 11/2003 (Wireless); Wireless Data Research
Group 2003; InStat/MDR 7/2004 (Handsets)
Low Data Rate WPAN Applications
Zigbee
Zigbee2006
2003
Pro
security
HVAC
AMR
lighting control
access control
asset mgt
process
control
environmental
energy mgt
BUILDING
AUTOMATION
CONSUMER
ELECTRONICS
PC &
PERIPHERALS
INDUSTRIAL
CONTROL
patient
monitoring
fitness
monitoring
TV
VCR
DVD/CD
remote
PERSONAL
HEALTH CARE
RESIDENTIAL/
LIGHT
COMMERCIAL
CONTROL
mouse
keyboard
joystick
security
HVAC
lighting control
access control
lawn & garden irrigation
Barriers to Adoption
Reliability
Standards
Ease of Use
Power consumption
Development cycles
Node size
0%
OnWorld, 2005
20%
40%
60%
80%
100%
Dust Networks
• Founded July 2002
• Focused on reliability, power consumption
• Developed TSMP
– Time Synchronized Mesh Protocol
– >99.9% reliability
– Lowest power per delivered packet
50 motes, 7 hops
3 floors, 150,000sf
>100,000 packets/day
Oil Refinery – Double Coker Unit
• Scope limited to Coker
facility and support units
spanning over 1200ft
• No repeaters were needed
to ensure connectivity
• Electrical/Mechanical
contractor installed per
wired practices
• >5 year life on C-cell
GW
400m
Standards
• IEEE 802.15.4
• Wireless HART
• ISA SP100
Wireless HART booth at ISA Expo, Oct. 2006
The De-facto Standard
12 Manufacturers,1 Network – Dust Networks’ TSMP
Emerson
MACTek
Yokogawa
Siemens
Siemens
ABB
Honeywell
Phoenix
Contact
Endress+
Hauser
Elpro
Smar
Pepperl+
Fuchs
Excerpts from Customer Presentations at the Emerson Process
Users Conference
October 2-5, 2006
Streetline Networks
Federspiel Controls
HVAC System Retrofits
Demonstrated Energy Savings:
• 3.7 kWh/sf/yr
• 0.34 therms/sf/yr
• Higher savings than conventional
retrofits
Barriers to Adoption
>99.9%
Reliability
Wireless HART, SP100
Standards
“It just worked”
Ease of Use
5-10 years
Power consumption
Complete networks
Development cycles
Node size
0%
OnWorld, 2005
20%
40%
60%
80%
100%
2.4 GHz Transceiver Front End
• Cook et al.,
ISSCC 2006
• Active Area:
0.8mm2
• Zero external
RF components
Radio Performance
25
X
20
With software:
10 years  D cell
IRX (mA)
cc2420
15
X
10
cc1000
With software:
10 years  coin cell
5
Cook 06 (300 mW)
Molnar 04 (0.4mA)
X
Otis 05 (0.4mA)
X
100k
X
200k
300k
Bit rate (bps)
RF Time of Flight Ranging in a Coal Mine Tunnel
Steven Lanzisera
70
60
Time of Flight (ns)
50
2 m Error
40
Measured
Data
30
Ideal
20
1 m Error
10
0
0
2
4
6
8
10
Distance (m)
12
14
16
18
Mote on a Chip? (circa 2001)
• Goals:
– Standard CMOS
– Low power
– Minmal external components
antenna
Temp
uP
SRAM
Amp ADC Radio
~2 mm^2 ASIC
battery
inductor
crystal
UCB Hardware Results ~2003
• 2 chips fabbed in 0.25um CMOS
– “Mote on a chip” worked, TX only
– 900 MHz transceiver worked
• Records set for low power CMOS
– ADC, Mike Scott, M.S.
• 8 bits, 100kS/s
• 2uA@1V
– Microprocessor, Brett Warneke, PhD.
• 8 bits, 1MIP
• 10uA@1V
– 900 MHz radio – Al Molnar M.S.
• 100kbps, “bits in, bits out”
• 20 m indoors
• 0.4mA @ 3V
Mote on a Chip, 2009
• Goals:
– Standard CMOS
– Low power
– Minimal external components
Zero
antenna
uP
Security
Temp
Location
Amp ADC Radio
Time
SRAM
~4 mm^2 ASIC
battery
inductor
crystal
Conclusion
• 10 years later, a real market emerges
• Reliable, low power, standards-based
technology is no more expensive than
junk
• The lowest power radios in the world
come from UCB/EECS/BSAC
• The best software and algorithms for
WSN come from UCB/EECS/BSAC