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Introduction to WLAN
Wireless LANs
รศ. ดร. อนันต์ ผลเพิม่Assoc. Prof. Anan Phonphoem, Ph.D.
Intelligent Wireless Network Group (IWING Lab)
http://iwing.cpe.ku.ac.th
Computer Engineering Department
Kasetsart University, Bangkok, Thailand
2
Outline
• WLAN Classification
• WLAN Architecture
• Other WLAN Architectures
WLAN Classification
3
Wireless LANs
ACTACT10M100M
1 2 3 4
13 14 15 16
5 6 7 8
17 18 19 20
9 10 11 12
21 22 23 24
UPLINK
1 2 3 4 5 6 7 8 9 101112
131415161718192021222324COLCOL
PWR
SWITCH
ACTACT10M100M
1 2 3 4
13 14 15 16
5 6 7 8
17 18 19 20
9 10 11 12
21 22 23 24
UPLINK
1 2 3 4 5 6 7 8 9 101112
131415161718192021222324COLCOL
PWR
SWITCH
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TCP/IP Protocol Suite(Internet Model)
Applications User service and interface5
Data Link2 Provide framesNode-to-node (same network segment)
Physical (mechanical and electrical spec)1Transmission bit streams
NetworkPacket end-to-end (across network)
3 Move packets from source to destination
Transport Process delivery + Error (TCP/UDP)4Reliable end-to-end (whole message)
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WLAN
TCP/IP & WLAN
Applications5
Transport4
Network3
Data Link2
Physical1
MAC, QoS, Security, Power mang.
Modulation, Frequency
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Outline
• WLAN Classification
• Radio Waves
• Infrared Light
• Carrier currents (“no new wire”)
• Powerline
• Phoneline
• Network Architecture
Infrared Light
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Electromagnetic Spectrum
Power,
Voice
Radio communication
Radio, microwave, satellite
Infrared
Light
Ultra-
Violet
Light
X, gamma,
Cosmic rays
0 3,000 Hz 300 GHz
Radio basedWLAN
InfraredWLAN
Carrier CurrentNetwork
Visible light
430-750 THz
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Infrared Light Based WLAN
• Invisible to the naked eye
• Infrared Light LAN operate @ 820 nm.
• Least attenuation by air
• Advantages over Radio Waves:
• More Secure
• Less susceptible to common noises (e.g.oven)
• Better performance High data rate
• Disadvantage:
• Limited Coverage
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Components
• Adapter Card (NIC)
• Protocol for accessing shared medium
• Transducer
• Similar to radio antenna
• Transmits & receive infrared light signal
http://www.electronics-lab.com/blog/?tag=wireless
LED (light emitting diodes)
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Point-to-point Infrared LAN
Token-Ring
Optical WLANInternet from the Ceiling Light
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Fraunhofer Heinrich Hertz Institute
http://www.hhi.fraunhofer.de/en/project-of-the-month/visible-light-communication/
• Visible Light Communication or VLC• Infrared LEDS• Five meters• Up to 800 Mbit/s (in the lab)
Li-Fi
• Light Fidelity
• Operate on Visible Light
• Use common household LED to enable data transfer
• ~70 Mbps
• Speeds of up to 224 gigabits per second
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Li-Fi
13https://i.ytimg.com/vi/DsJ4YtaUQPU/hqdefault.jpg
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Outline
• WLAN Classification
• Radio Waves
• Infrared Light
• Carrier currents (“no new wire”)
• Powerline
• Phoneline
• WLAN Architecture
• Other WLAN Architectures
• Carrier currents (“no new wire”)
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Home Network
Office
Living Room Bed Room 2
Bed Room 1Kitchen
ResidentialGateway
Modified from
“Multimedia friendly home wireless LANs”Aura GanzAnan PhonphoemKitti Wongthavarawat
Telematics and Informatics, 2001, Volume 18, Issues 2–3
RadioPowerlinePhoneline
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Home Network
http://media.memoryexpress.com/Assets/Products/MX50120/dl_dhp601av_3.jpg
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Powerline Network
• Carrier-current network
• Wiring from the distribution transformer
• many houses share the same media
• Start with the low speed for control application
60 Hz 10 KHz - 10 MHz
Power PowerlineCommunications
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Powerline Network
• X-10
• CEBus
• LONworks
• Echelon
• HomePlug
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Powerline Network Device
Netgear Wireless Range Extender Kit
85Mbps Ethernet HomePlug 1.0 Turbo
Piggy6• 6-way extension lead• 3 Ethernet ports switch• HomePlug 200Mbps
http://www.solwise.co.uk/net-powerline.htm
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Phoneline Network
• Existing phone wiring
• Similar to powerline communication
• Implement frequency division multiplex
Voice
POTS xDSL Phoneline
communications
20Hz - 3.4KHz 25KHz - 1.1MHz 5.5 - 30 MHz
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Phoneline Network Device
2Wire USB PC Port Phone Line 10Mbps USB Adapter
HomePNA PCI Network Interface CardFrequency Range: 5.5 - 9.5 MHz
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Common Characteristics
•Shared broadcast media
•Harsh channel condition
•attenuation, noise, and interference
•Changing channel condition
•Dynamic network topology
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Outline
• WLAN Classification
• Radio Waves
• Infrared Light
• Carrier currents (“no new wire”)
• Powerline
• Phoneline
• WLAN Architecture
• Other WLAN Architectures
Radio Waves
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ISM Bands
• Industrial, Scientific, and Medical frequency band
• Can operate without FCC licenses
• Tx output power 1 watt
• Eliminate cost and time consuming for licenses
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ISM Bands Radio Spectrum
• Cheaper• Few area• Longer Tx Range
• High BW, high data rate• Less susceptible to noise• Less Tx Length
• Worldwide
26MHz
902MHz
928MHz
902 MHz
83.5 MHz
2.40GHz
2.4835GHz
2.4 GHz
125 MHz
5.725GHz
5.850GHz
5.7 GHz
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Radio Based Wireless LANs
• Advantages
• No line of sights
• Propagate through obstacles
• Disadvantages
• Interference
• Security
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Components:
Wireless Access Point
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Components:
WLAN Network Interface Card
For Notebook Computer
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Components:
WLAN Network Interface Card
USB Type USB Type: with external antenna
ChargerBuy
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Components:
WLAN Network Interface Card
Built-in
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Components:
WLAN NIC for Desktop
PCMCIA Adapter
D-Link DWA-556 Xtreme N Wireless PCI
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Components:
Antenna
• Micro-strip Antenna
• Omni/directional
• Indoor/Outdoor
http://free-download-update.blogspot.com/2008/01/14dbi-18dbi-and-205dbi-pcb-panel-wifi.html
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Directional Antenna
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Indoor Directional Antenna
Source: www.techworks.com
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Outdoor 2.4 GHz Band Antennas
24-dBi Directional Antennawith Up/Down Converter on Mast
6-dBi Omni-Directional Antennawith Up/Down Converter on Mast
Source: Wi-Lan Technology (UC Wireless)
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Other Components
• WLAN Bridge
• WLAN Router
• VLAN Switch
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Selecting Products
• Functionality
• Availability
• Support
• Price
• Standard compliance
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Outline
• WLAN Classification
• WLAN Architecture
• WLAN Topology
• WLAN Design and Implementation
• Other WLAN Architectures
WLAN Topology
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WLAN Topology
• Physical: Single Cell & Multiple Cells
• Logical: Ad-hoc & Infrastructure
• Connectivity: Standalone & Wired Network Interface
• MAC: Distributed & Centralized
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Physical:Single Cell VS. Multiple Cells
AP AP AP
Multiple CellsSingle Cell
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Logical:Ad-hoc VS. Infrastructure
Infrastructure
AP
Ah-hoc
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Connectivity:Standalone VS. Wired Network Interface
Standalone
AP
Wired Network Interface
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MAC:Distributed VS. Centralized
Distributed Centralized
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Outline
• WLAN Classification
• WLAN Architecture
• WLAN Topology
• WLAN Design and Implementation
• Other WLAN Architectures
WLAN Design and Implementation
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WLAN Design and Implementation
• Define network elements
• Select products
• Site survey
• Verify the design
• Document the design
• Procure components
• Installation
• Testing
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Cost of Ownership
• Infrastructure costs
• Client device costs
• Monthly costs (Power & Internet Access)
• Management costs
• Training
• Downtime costs
• Support costs (Troubleshoot + repair)
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Infrastructure WLAN
• Need an Access Point
• Connect to the wired LAN
• Need Infrastructure
• Need administration
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Infrastructure WLAN
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Infrastructure WLAN
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Roaming
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SOHO Infrastructure WLAN
Hub/Switch
ComputerServer
Access Point
Printer
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(Large) Infrastructure WLAN
Router
Internet
Hub/Switch
LAN
Hub/Switch
LAN
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Communication Path (End-to-End)
Applications
Transport
IP
802.11
Physical
Router
Hub/Switch/Bridge Hub/Switch/Bridge
802.3
Physical
IP
802.3
Physical
802.3
Physical
802.3
MAC
Physical
802.11
MAC
Physical
Relay
Applications
Transport
IP
802.11
Physical
802.3
MAC
Physical
802.11
MAC
Physical
Relay
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Simple WLAN Management
Router
Internet
Hub/Switch
LAN
Hub/Switch
LAN
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VLAN Switch Management
Router
Internet
VLAN Switch VLAN Switch
LAN
LAN
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AP with VLAN Capability
Router
Internet
Hub/Switch
LAN
Hub/Switch
LAN
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Outline
• WLAN Classification
• WLAN Architecture
• Other WLAN ArchitecturesOther WLAN Architectures
Other WLAN Architectures
• Wireless Mesh Network
• Wireless Ad hoc Network
• Wi-Fi Direct, Wi-Fi P2P(Printer)
• Wireless Sensor Network
• Wireless Video Sensor Network (WVSN)
• Mobile Ad-hoc Network (MANET)
• Vehicular Ad-hoc Network (VANET)
• Delay-Tolerant Networking (DTN)
• Femtocell
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Wireless Video Sensor Network (WVSN)
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DeerNet http://spie.org/x14634.xml?highlight=x2410
Delay-Tolerant Networking (DTN)
61http://protogenist.wordpress.com/2012/07/18/dtn-network-model-evolution/
Delay-Tolerant Networking (DTN)
62http://protogenist.wordpress.com/2012/07/18/dtn-network-model-evolution/
Femtocell
• Provide indoor coverage (Macrocell cannot)
• Offload traffic from Macrocell (improve Macrocell capacity)
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FAP: Femtocell Access Point (UMTS/HSPA/GSM/EDGE/LTE)
http://www.smallcellforum.org/aboutsmallcells-small-cells-consumer-faqs
Macrocell
