A rearrangement algorithm for scheduled automatic power save delivery of wireless LANs

Tsern-Huei Lee*, Jing Rong Hsieh, Hsiao Wei Chen

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

1 Scopus citations


One of the major challenges to integrate the wireless LAN technology into portable devices is the limited battery life. The IEEE 802.11e introduced an advanced architecture to improve 802.11 power saving mechanism, named Scheduled Automatic Power Save Delivery (S-APSD). In S-APSD, the access point negotiates periodical schedules with wireless Stations (STA) to deliver buffered traffic and thus prevents the need to poll for each frame by STAs. In S-APSD, in order to reduce wastage of energy, the AP has to avoid overlapping of Service Periods (SPs). Based on existing scheduled events (SEs), the OAS-APSD (Overlapping Aware S-APSD) and LCS-APSD (Low Complexity S-APSD) were proposed to incrementally select the Service Start Times (SSTs) for the new joining traffic streams (TSs) to minimize the chance of SP overlapping. However, in this scheduling fashion, the resulted power saving performance depends on the joining order of TSs and thus may be unsatisfactory. Therefore, our idea is to rearrange the relative offsets of existing SEs to enlarge the system minimum distance. From numerical results, we find that the proposed scheduling algorithms can provide better power saving.

Original languageEnglish
Title of host publicationTENCON 2010 - 2010 IEEE Region 10 Conference
Number of pages6
StatePublished - 1 Dec 2010
Event2010 IEEE Region 10 Conference, TENCON 2010 - Fukuoka, Japan
Duration: 21 Nov 201024 Nov 2010

Publication series

NameIEEE Region 10 Annual International Conference, Proceedings/TENCON


Conference2010 IEEE Region 10 Conference, TENCON 2010


  • Power Saving
  • Scheduling
  • Wireless LAN

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