IntroductionWSN-Week3-1.pptx - Introduction to WSNs Prof....

Introduction to WSNs
Prof. Shuang-Hua Yang
[email protected]
1

Contents
•
Wireless LAN
•
What are WSNs
•
Evolution of WSNs
•
Research fields involved in WSNs
•
Summary

IEEE 802 model
Layer 4-7
Network Layer
Data Link layer
Physical Layer
Application
Network Layer
Logical Link Control (LLC)
Media Access Control (MAC)
Physical Layer
7 Application
6 Presentation
5 Session
4 Transport
3 Network
2 Data Link
1 Physical
Open System Interconnection (OSI) model
OSI model IEEE 802 model

Wireless Technologies
•
Two common types of technologies are used for transmission of information in
wireless devices:
• Infrared (IR) technology: for indoor use as IR rays cannot penetrate walls, ceilings or other
obstacles, and needs a line of sight between each other.
•
Radio frequency (RF) technology. Two types of RF signals
•
Narrowband signal: a signal with a narrow spectrum and transmitted at a specific frequency.
• Spread-spectrum signal: the information is transmitted over a range of frequencies. Spread-spectrum is one of
the most popular signal types for wireless devices.
frequency
Power

ISM and U-NII bands
• The Federal communication committee (FCC) allocates a separate range of frequencies to
different use such as TV, radio. The ISM band is for Industrial, Scientific research, and Medical
applications, does not require a license and the transmission power is less than 1 watt.
• Unlicensed National Information Infrastructure (U-NII) band consists of three 100 mHz bands and
uses a specific transmission power
Industrial band
I-band
Scientific band
S-band
Medical band
M-band
902 MHz 928 MHz 2.4 GHz 2.48 GHz 5.725GHz 5.85 GHz
40 mW 200 mW 800 mW
5.15 GHz 5.25 GHz 5.35GHz 5.725 GHz 5.82 GHz

Zigbee Communication Protocol
•
The name comes from the honeybee, which use a zig-zag type of dance to
communicate with other members.
•
Developers want to emulate this action for simply solving complex tasks.
•
A new standard developed by the ZigBee Alliance for personal-area-network
(PAN).
•
The ZigBee protocol stack is built on top of IEEE 802.15.4

Specification History
•
Oct 2002---Zigbee Alliance founded
•
Dec 2004---Zigbee Specification 1.0 Draft ratified
•
June 2005---Zigbee Specification 1.0 published
•
Dec 2006---Zigbee Specification 1.1 published
•
2007---Zigbee 2007 Pro Draft

ZigBee, Bluetooth and WiFi
•
Motivation of Zigbee Technology
D a t a B i t R a t e
( M b p s )
C o m m u n i c a t i o n
R a n g e
( m )
Z i g b e e
8 0 2 . 1 5 .