9933107 動機14 林昱彤
100062119 資工15 王敬嘉
 Introduction
 Goal
 Fair
Comparison
• Hardware, OS selection
 Measurement
• Application description, Measurement approach
 Result
 Discussion
 Conclusion
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無線感測網路
•
•
A system consisting of a collective of networked
sensor nodes designed to intercommunicate via
wireless radio.
sensor, processor, communication
1. 省電
2. 價格低廉
3. 體積小
網路
衛星
其他傳輸媒介
server
動機14 林昱彤
Wireless Data
Collector
WSN region
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 Application
domains:
◦ 軍事、商業、醫藥、安全和生態學等
 Challenge:
◦ resource-constrained nature of WSN hardware
platforms
◦ dynamic operational environment
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 the
performance of the WSN operating systems
 to make an informed choice when selecting an
operating system for WSN developers
software life cycle:
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

Tmote Sky is a TI MSP430-based hardware platform
that provides a 16-bit microcontroller clocked at
8MHz running on a 3V power supply.
TelosB has the hardware sensors for temperature,
humidity and light. In addition, it has a CC2420
802.15.4 radio chip for communication with
neighbouring nodes.
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 Three
criteria of selecting:
• actively maintained and supported
• support test platform: the Tmote Sky
• Provide support for remote reprogramming
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
Tiny OS

Contiki OS

Lorien OS
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designed for networked embedded devices.
Advantages:
 NesC : reduces the memory requirement
 consumes less resources
Disadvantages:
 does not preserve component structure after compilation
 lack of available implementations
version-2.1.2
used the built-in interfaces of TinyOS for sensing and radio
communication
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
designed for use in WSN applications which require
support for IP-based communication.

Advantages:
◦ supports a wide range of hardware platforms
◦ works with modular upgrading methodology

version-2.6

use the pre-defined methods of Contiki for sensing
and radio communication
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Architectural model similar to TinyOS
 preserves its component-structure throughout the
software life cycle


Advantages
◦ well suited for dynamic operating environments

version-2.8.4

Use the built-in interfaces for sensing and radio
communication
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 Use
6 example Applications
 From simple to complex
◦ Use Sensor or not ?
◦ Use Radio or not ?
◦ The functions are complicated or not ?
資工15 王敬嘉
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Applications
Sensor
Radio
Function
Blink
X
X
• Toggle LED once/ per sec
Sense
O
X
• Sample SHT11 sensor once/per sec
• Blink LED
Blink-Remote
(BlinkRx)
X
O
• Toggle LED when receive message
via CC2420 radio
Sense-Remote
(BlinkTx)
O
O
• Sample sensor once/per sec
• Transmit sensor reading using radio
Aggregate
O
O
• Receive messages from radio
• Buffer message
• Transmit to gateway when buffer full
Encryption
(XTEA)
O
O
• Receive messages from radio
• Encrypts message by XTEA algorithm
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 Development
-> counting LOC
 Use OS-specific software tool
 Calculate each application 10 times
<- Power
Consumption
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 By
counting the LOC (Lines of Code)
 Tiny OS & Lorien : 70 lines avg/each app
 Contiki : 39 lines avg/each app
Contiki is best in rapid prototyping !
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
In flash ROM
Converge!
Tiny OS win!
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
In RAM
Lorien : overhead of compomentization
Contiki : need Build-time optimisation
Tiny OS the best !
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Contiki
: consumes
more
energy
Aggregate
: sampleOS
sensor
5 times then
transmit;
use !more radio
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Size of the binary artefact to be transmitted
Tiny OS : need entire app to be transmitted 
poor in dynamic scenarios
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
Software reconfiguration : 2 steps
◦ App artefact be injected into hardware platform
◦ Hardware platform restart or new app artefact integrated
with OS runtime
Tiny OS : 2 commands
 Contiki : 2 commands
 Lorien : 7 commands average


Lorien is much complex
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Contiki
OS
Development _ LOC
Tiny
OS
-
Execution _ Memory : RAM

-
Execution _ Memory : ROM
Tiny OS  >> Converge
Execution _ Energy
-

-
Reconfiguration _ artefact
size

-

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
Lorien
OS
-
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Bad (*) Average(**) Good(***)
Tiny OS : for simple and static apps
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
WSN apps remain as a challenge
◦ Resource-constrained hardware platform
◦ Dynamically changing application environment
Help WSN developers to select OS for WSN
apps
 Future Work

◦ Explore dynamic optimisation of WSN OS
◦ Design their own OS that combines all the
benefits
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Thank YOU !
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