Mob 4 wireless lan 2010

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Internet & Mobile Communications
 Wireless LANs
 Characteristics
 Wi-Fi Research
 IEEE 802.11
 Introduction
 PHY
 MAC
 Management
 Wi-Fi Alliance and IEEE 802.11
Mobile Internet 2010
Need for standardisation
 Mobility  frequency regulation between
countries is necessary : common frequency
band
 Limitation of battery usage
 Limitation of interferences among different
equipments (antennas can help)
 configuration as seamless as possible
 Compatibillity with existing LAN technologies
 Seamless for users and applications (location
aware applications…)
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Mobile Internet 2010
Characteristics of wireless LANs
 Advantages
– very flexible within the reception area
– Ad-hoc networks without previous planning possible
– (almost) no wiring difficulties (e.g. historic buildings, firewalls)
– more robust against disasters like, e.g., earthquakes, fire - or
users pulling a plug...
 Disadvantages
– typically very low bandwidth compared to wired networks
(1-10 Mbit/s)
– many proprietary solutions, especially for higher bit-rates,
standards take their time (e.g. IEEE 802.11)
– products have to follow many national restrictions if working
wireless, it takes a vary long time to establish global solutions
like, e.g., IMT-2000
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Mobile Internet 2010
Design goals for wireless LANs
– global, seamless operation
– low power for battery use
– no special permissions or licenses needed to use the LAN
– robust transmission technology
– simplified spontaneous cooperation at meetings
– easy to use for everyone, simple management
– protection of investment in wired networks
– security (no one should be able to read my data), privacy (no
one should be able to collect user profiles), safety (low
radiation)
– transparency concerning applications and higher layer
protocols, but also location awareness if necessary
4 7.2.1
Mobile Internet 2010
Comparison: infrared vs. radio transmission
 Infrared  Radio
– typically using the license
– uses IR diodes, diffuse light, multiple free ISM band at 2.4 GHz
reflections (walls, furniture etc.)
 Advantages
 Advantages – experience from wireless
– simple, cheap, available in many WAN and mobile phones
mobile devices can be used
– no licenses needed – coverage of larger areas
possible (radio can
– simple shielding possible penetrate walls, furniture
 Disadvantages etc.)
– interference by sunlight, heat sources  Disadvantages
etc. – very limited license free
frequency bands
– many things shield or absorb IR light
– shielding more difficult,
– low bandwidth interference with other
 Example electrical devices
– IrDA (Infrared Data Association)  Example
5 interface available everywhere – WaveLAN, HIPERLAN,
Bluetooth
Mobile Internet 2010
Internet & Mobile Communications
 Wireless LANs
 Characteristics
 Wi-Fi Research
 IEEE 802.11
 Introduction
 PHY
 MAC
 Management
 Wi-Fi Alliance and IEEE 802.11
Mobile Internet 2010
Wifi Research
Andrew Miles - CISCO
 Research shows 802.11 (aka Wi-Fi)
is becoming an essential part of our
everyday lives
– Research in the US reveals some
factoids about the impact of Wi-Fi …
 80% say Wi-Fi is more essential than
their iPod
 81% would rather see their favourite
team lose than give up Wi-Fi for a week
 90% would rather do without their daily
Starbucks than their Wi-Fi
Source: WFA/Kelton Research,
– … the bottom line is that Wi-Fi is July & October 2006
affecting real people in their everyday
lives
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Andrew Miles - CISCO
Mobile Internet 2010
Wifi Research
Andrew Miles - CISCO
 Wi-Fi has become popular
based on products that are
not optimised for wireless
use …
– .. with apologies to all those
in the PC industry
 Not very usable while on
the move
 Not really suitable for many
voice applications
 Until recently, laptops were
mainly an enterprise style
product
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Mobile Internet 2010
Wifi Research
Andrew Miles - CISCO
 … and yet the Wi-Fi
200 market reached over 200
millions chipsets per year
160 in 2006
– In 1997, the first IEEE
Devices (million)
120
802.11 standard was ratified
– In 2005, over 150 million
Wi-Fi devices were sold
80 – In 2006, over 200 million
Wi-Fi devices were sold
(33% growth rate)
40 Enterprise APs
Home/SOHO
0 CE
9 Phones
Source: In-Stat 2005 2006
Mobile Internet 2010 PCs
Wifi research
Andrew Miles - CISCO
 Wi-Fi is now being implemented in a wide
variety of more interesting devices …
Nokia N series
Nabaztag
Microsoft Zune
10 Sony mylo Nikon Coolpix
Mobile Internet 2010
Sony PS3
… including lots of Wi-Fi & Wi-Fi/cellular
converged phone devices …
Andrew Miles - CISCO
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Mobile Internet 2010
Wifi Research
Andrew Miles - CISCO
 … with some of the new devices
actually used for voice (and not just
data) …
– Numerous Wi-Fi carrier voice and data deployments
are underway, and others expected during 2007 and
2008
– Wi-Fi with UMA is the predominant voice approach
today, although SIP solutions also exist
– Examples of voice deployments include:
 BT Fusion:voice & data in the home/office network at
more than 2,000 Openzone hotspots
 Orange Unik for Professionals: provides Wi-Fi to GSM
handoff, and includes unlimited use for Wi-Fi calls
 NTT DoCoMo: SIP-based voice for large enterprise
customers
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Mobile Internet 2010
Wi-Fi Research
Andrew Miles - CISCO
 … based on access in many
locations outside the home
or office …
– 143k+ hot spots in 132 countries
 Source: JiWire (12 March 2007)
 Other sources indicate 200k+ hot
spots
– 500+ muni deployments in 29
countries
 Source: Tropos & WFA
– 82% of US hotels offer Wi-Fi
 Source: American Hotel & Lodging
Melbourne
Assn
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Mobile Internet 2010
Wi-Fi Research
Andrew Miles - CISCO
 … which means the
Not far from 1B!
700 promise of one billion
600 chipsets sold in a year
CE might not be far off!
500
Devices (million)
– Both CE and Voice are forecast to
400 make a big impact by 2010
Voice – They will enable even more use of
300 Wi-Fi both in all market segments
– One billion chipsets is forecast by
200 2012 Enterprise APs
Home/SOHO
100
CE
0 Phones
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2006 2010 PCs
Mobile Internet 2010
Internet & Mobile Communications
 Wireless LANs
 Characteristics
 Wi-Fi Research
 IEEE 802.11
 Introduction
 PHY
 MAC
 Management
 Wi-Fi Alliance and IEEE 802.11
Mobile Internet 2010
Introduction IEEE 802.11
 L'IEEE (Institute of Electrical and
Electronics Engineers) has
normalised several categories of
local area networks
– Ethernet (IEEE 802.3)
– Token Bus (IEEE 802.4)
– Token Ring (IEEE 802.5)
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Mobile Internet 2010
Introduction IEEE 802.11
 1990: launching of the project to create a
wireless LAN - WLAN (Wireless Local Area
Network)
– Goals:
 to offer a wireless connectivity to fixed workstations of
mobile workstations
 to allow fast deployment inside a local area
 To permit the use of different frequency bands
– 2001: publication of the first International standard
for wireless LAN developped by the IEEE
organisation.
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Mobile Internet 2010
Introduction IEEE 802.11
 Frequencies are chosen in the 2,4 GHz Band (as for
Bluetooth technology)
– No need for licensing
– Band in not completely free in many countries
 Communications
– Can be direct from terminal to terminal
 It is then impossible to relay frames from one terminal to another
– With an Access Point which relays all the traffic
 Transmission rates vary depending on coding technics
which are used and of the bandwidth allocated.
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Mobile Internet 2010
Introduction IEEE 802.11
 Access Method to the physical layer (MAC
protocol - Medium Access Control)
– Quite complex
– Many available options on the radio interface
– Access Technics derived from CSMA/CD
 Carrier Sense Multiple Access/Collision Detection, used to
define the access in wired networks
 Problem: In wireless networks it is impossible to detect
collisions as for Ethernet LANs.
– Introduction of a new protocol : CSMA/CA (Carrier Sense
Multiple Access/Collision Avoidance)
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Mobile Internet 2010
IEEE 802.11
 802.11 - Main Standard (june 1997)
– Le groupe de travail concentre maintenant ses efforts pour produire
des standards pour des WLAN à grande vitesse
 802.11x - Amendements
– 802.11b - speed up to 11 Mbits/s (ISM band)
– 802.11a - speed up to 54 Mbits/s (UN-II band)
– 802.11g - speed up to 54 Mbits/s (bande ISM)
– 802.11h – dynamic selection of frequencies and power control (UN-II
band)
– 802.11e - Quality of service
– 802.11f - Roaming
– 802.11i - security improvements
– 802.11n - MIMO
– …
– 802.11v - goal : create an interface of the higher layer which allow to
manage wireless devices.
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Mobile Internet 2010