Fast Handoff in WiFi Networks

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Fast Handoff in Wi-Fi Networks

• David Murray

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What is Handoff and Roaming?
Network 10.0.0.0
ESS Coverage Area
Access Point 1
Access Point 2
SSID VoWiFI
SSID VoWiFI
Wireless Client
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Why?

• VoWi-Fi
• Cost saving technology
• Telephone revenue 250B US(2000)
• ISP revenue 10B US(2000)
• High bandwidth multimedia streaming
• Stream live sporting events
• Radio, Music

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Handover Issues with VoWi-Fi
Too slow, over 1 second The goal under 50
ms IEEE 802.11r is working on the authentication
and re-association phases. My study focuses on
the probe delay. Probe delay accounts for over
90 total handoff delay.
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Previous Research in Handoff

• Vendors scanning mechanisms result in variable
  handoff time.
• Lowering handoff latency by
• Increasing AP beacon interval
• Tweaking of timers
• Previous studies measured handoff in the IEEE
  802.11b 2.4Ghz region.

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Handoff in the 5.8 Ghz Spectrum
Apply the techniques of Pries ,Vatn and Mishra
to investigate handoff in the 5.8Ghz region

• 5.8Ghz Region is ideal for VoWi-Fi
• More useable channels
• Less interference
• More bandwidth

The Research Question How fast is handoff in the
IEEE 802.11a 5.8Ghz spectrum
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Questions?