2. Project Team:
IIT Electrical and Computer
Engineering Dept.
• Interns: MSEE students
– Kaihe Xu
– Nirnimesh Ghose
– Tingting Han
– Shadi Dahman
• Advisor
– Ken Zdunek
3. Project Timeline
Initial
Discussions
Exelon
Go-Ahead
Kickoff
at Byron
Demo and
RF Survey
at Byron
Final Demo
at IIT
Sensor
Selection
June July AugustMay
Internal
Demo
System
Evaluation
1
Contract
27
-- March April
Initial IIT
Proposal
Team
Selection
● ●●●
9
●
22
Sep
1
●
30
Go-Ahead to Completion
4 months
Time-to-
Contract
Project Duration
~3 months
4. Project Review Outline
• Project Background, Motivation and
Goals
• Architecture
– Target System Architecture
– Demonstration Architecture
• Wireless range and penetration
through walls
– Propagation vs distance; use of relays/mesh
• RF Coexistence
– WiFi (802.11g.n) and Zigbee (802.15.4)
– Byron RF Environment Scan
• Wireless Temperature Sensors
– Requirements and Evaluation
• Deployment
– Approach for Byron
• Security
• Conclusions and Next Steps
5. Wireless Sensor Project
• Motivation
– Increase equipment life and availability by monitoring operating
environment in a nuclear plant.
– Use consumable/commodity sensor network for low-cost
monitoring and troubleshooting.
– Use wireless sensor network to minimize installation costs.
• Goals
– Investigate state-of-the-art wireless sensors.
– Develop recommendation for a Byron wireless sensor network.
– Design a prototype sensor network and demonstrate it in former
IIT reactor room.
– Analyze the spectrum usage and co-existence issue with Wi-Fi in
Byron.
– Study sensor network security and deploy the security service in
the prototype network.
13. Byron RF spectrum
analysis 850MHz-950MHz
Conclusion:
Point 6 can
operate in Byron
* Data is taken in
July 22, 2011
14. Byron RF spectrum
analysis 2.4GHz-2.5GHz
1. Wifi is seldom
used
2. There is enough
space between
Wifi channels
* Data is taken in
July 22, 2011
15. Temperature Sensors
Requirements
• Radio Range : Good penetration through concrete walls
• Size : As small as possible
• Operating Temperature : Room temperature
• Sensing temperature: 0 to 220 (°F)
• Controllability : Programmable to change reading rate
• Usual Reading Rate : 1read/5 minutes
• Mounting : Magnet, Epoxy, no screw
• Measurement accuracy : 1 °F difference
• Energy source:
– ideal: ambient energy harvesting
– acceptable: battery
16. Sensor Candidates
Digi Xbee Point 6 Zigsense
Radio Transceiver 2.4GHz
(zigbee 802.15.4)
900 MHz SSFH
(proprietary protocol)
2.4 GHz
(zigbee 802.15.4)
Size 2.5” x1.3”x2.7” 3.25”x3.25”x1.65” 4.7”x3.5”x2.4”
Temperature range (°F) -0.4 to +130
(internal sensor)
-40 to 250
(internal / external)
-44 to 260
(internal /external)
Battery life* 2.5y, 1read/30s, Up to 2 years, 1
read/5min
2y, 1read/120s
Transmission range**
(outdoor line-of-sight)
120m 400m 400m
Transmission range***
indoor (experimental)
~ 30m ~ 65m ~ 30m
* (Battery life is a function of duty-cycle)
** (From datasheet)
*** (Indoor range is a function of the obstruction environment)
18. Proposal for installation
in Byron Turbine Buiding
Point Six Digi & Zigsense
Sensor
Locations
Sensor distributed anywhere
inside the range of router or
gateway
Sensors distributed anywhere inside
the range of router or gateway.
Zigsense for high temperature, and
further distance from router or gateway
Router RF Mesh Repeater 9.9 RF0514
(not investigated yet)
Plug in AC outlet. 1 or 2 routers on
each floor, depending on obstructions
Gateway Connected to bridge by Ethernet
cable
Connected to bridge by Ethernet cable
Bridge Put within Wifi coverage of an
Access Point
Put within Wifi coverage of an Access
Point
Software/
Application
Promis & Messenger run on
Local network, no Internet
• Digi Python Application Project
could run on local network.
• Evaluate the security of iDigi Dia
Service, and use it to reduce
development efforts
19. Proposed network
architecture
1. Use router to form
a mesh network to
cover the whole
Turbine building
2. Sensors join the
network by an
drop-in manner
R: Router
S: Sensor
20. Proposal for installation
in Byron Turbine Buiding
– Example & cost for deployment
• Digi & Zigsense: 30 sensors (15 Digi, 15 Zigsense),
9 routers, 1 gateway
• Point Six: 30 sensors, 2 routers, 1 gateway
• 1 bridge
• Total hardware cost: $ 19,000
21. Technical Issues
Zigbee Security
• Zigbee Application data security:
Message integrity: protects message from being modified in transit
Authentication: provides assurance on the originator of message
Freshness: prevents replay attacks
Privacy :prevents an eavesdropper from listening messages
• Zigbee Infrastructure security:
Network access control
Integrity of packet routing
Prevent unauthorized use of packet transport
Zigbee has inherent protection against unauthorized
wireless access
23. Conclusions
• Wireless sensing network is feasible
– 802.11g/n can be used to backhaul temperature
measurements from Zigbee 802.15.4 network
– 2-3 year sensor battery life, depending on duty cycle
• Dynamic measurement duty cycle
– Zigbee–based security/privacy prevents unauthorized
access
– Temperature readings available in spreadsheet format
– Robust architecture allows intermix of Zigbee and 900
MHz sensors
– Cost for Byron: 3 floors with 10 sensors/floor. Total
hardware cost: $ 19,000
24. Potential Next Steps
• Real-time temperature reading
delivery to laptop/desktop
• Proof-of-concept deployment
at Byron
• Ambient-energy powered sensor (heat, vibration)
• Define comprehensive device specification for nuclear
industry
– Technology exists for Byron to accomplish low-cost
environment monitoring, but hardware not optimized
for Nuclear Plant
• Investigate add-on device to transmit the
temperature readings wirelessly from existing meters.
