WiMAX

CS441 Dr. Kemal Akkaya

12/8/2011

By: Chun-Cheng Chuang

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Contents What is WiMax Why WiMax WiFi vs. WiMax WiMax PHY/MAC layer Challenges Conclusion

What is WiMAX Worldwide Interoperability for Microwave

Access Wireless MAN (Wireless Metropolitan Access

Network) Broadband wireless networks

based on the IEEE 802.16 standard.

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What is WiMAX Offers data transfer rates of up to 75 Mbit/s A range of up to 30 miles to make broadband

network access widely available Without wires

Last Mile access

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Why WiMax End-user are used to high bandwidth from

fixed sources Speed

higher range and speeds compared to 802.11 Wireless

Easier to extend to suburban and rural areas Broad Coverage

Much wider coverage that WiFi

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WPAN vs. WLAN vs. MAN

Standard Transmission distance

Max rate

WPAN Bluetooth (802.15.1)Zigbee (802.15.4)

1~10 M 20 to 250 (Kbps)/ ~700 (kbps)

WLAN Wi-Fi(802.11 a/b/g) 50~100 M 11~54 (mpbs)

MAN WiMAX (802.16) 30 miles 75 (mbps)

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WiMax PHY layer OFDM (orthogonal frequency division

multiplex) More advanced: MIMO (multiple-input and

multiple-output)

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WiMax MAC layer Connection-oriented A fundamental premise of the MAC

architecture is quality of service (QoS) QoS provided via service flows

Applies to both downlink (DL) and uplink (UL)

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WiMax MAC layerInterface to higher layer protocols, classifies incoming data, etc.

Core MAC functions (i.e., scheduling, connection maintenance,fragmentation), QoS control

Encryption, authentication, secure key exchange

Service Specific Convergence Sublayer

MAC Common Part Sublayer

Privacy Sublayer

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Applyciation Metro Area Networks High-Speed Internet Clustered wifi hotspot Wireless VoIP Video-on-demand, video surveillance Education (rural schools & government orgs.)

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Source :http://files.shareholder.com/downloads/INTC/1557442122x0x195859/40AB6084-0A42-4E87-9AD3-B08BADAA987F/wimax_and_wifi_together.pdf

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Challenges Security issues Eavesdrop Masquerade

Instead of sending packet to server, client send it to Hacker.

(Hacker takes identity of server.)

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Challenges Denial of Service

Attackers make resources (server, bandwidth) unavailable to client by overwhelming resource.

Jamming Block the service by sending out radio waves

along the same frequencies that WiMax use.

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Conclusions WiMax may becomes the dominant standard

for Wireless MAN in the realistic market. WiMax connect you faster and from much

longer ranges An intrusion detection system approach and

firewall can be used to address some of the threats.

More research is needed.

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References http://www.wimaxforum.org/

http://www.scribd.com/doc/59582733/WiMax-Final-Ppt

http://media.techtarget.com/searchMobileComputing/downloads/Finneran.pdf

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Thank you!