Research Highlights Power-Saving Issues

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Research HighlightsPower-Saving Issues
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Outline

• E. S. Jung and N. Vaidya, An Energy Efficient
  MAC Protocol for Wireless LANs, INFOCOM 2002.
• Eun-Sun Jung and Nitin Vaidya, A Power Control
  MAC Protocol for Ad Hoc Networks, ACM
  International Conference on Mobile Computing and
  Networking (MobiCom), September 2002.
• Y.-C. Tseng, C.-S. Hsu, and T.-Y. Hsieh,
  Power-Saving Protocols for IEEE 802.11-Based
  Multi-Hop Ad Hoc Networks, IEEE INFOCOM, 2002.

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Research HighlightATIM window length adjustment

• ATIM window length has performance impact on an
  ad hoc network.
• How to choose a proper size of ATIM window?
• Ref E. S. Jung and N. Vaidya, An Energy
  Efficient MAC Protocol for Wireless LANs,
  INFOCOM 2002.

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Research HighlightAsynchronous PS for multi-hop
MANET

• Y.-C. Tseng, C.-S. Hsu, and T.-Y. Hsieh,
  Power-Saving Protocols for IEEE 802.11-Based
  Multi-Hop Ad Hoc Networks, IEEE INFOCOM, 2002.
• Problem statement
• clock drift (asynchronous)
• network partitioning
• Example
• Proposed solutions
• dominating over ½ of awake time
• periodical wake up fully from time to time
• quorum from quorum concept in distributed systems

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Research HighlightSoft handover by PS mode

• for soft handover
• 802.11 only allows hard handover
• searching for new AP only after a STA loses its
  previous AP
• thus, causing long delay (e.g., VoIP services are
  delay-sensitive)
• to support soft handover, a STA must frequently
  scan new APs
• approach
• using PS mode as an excuse to search for
  neighboring APs (through such as an full frame
  with PS bit 1)
• the old AP will buffer frames during the PS
  period.