Reducing voice over WLAN call setup delay under limited access point buffer

Shiao-Li Tsao*, Tai Xing Yu

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Voice over WLAN (VoWLAN) service is regarded as one of the killer applications for public and private WLANs, but it suffers from a number of technical challenges, especially the power consumption problem. In order to conserve the energy of a VoWLAN device during idle, the power saving mode (PSM) defined in the IEEE 802.11 is widely employed. Experimental results indicate that 300ms to 1000ms listen intervals of PSM for a VoWLAN device could achieve better energy efficiencies. Unfortunately, low-end WLAN access points (APs) typically have limited memory spaces, and can buffer incoming packets for a small time window, say 100ms. For a VoWLAN device requesting long listen intervals, packets queued on the APs might be dropped or overwritten when the buffer overflows. This phenomenon introduces considerable call setup delays for session initiation protocol (SIP) that implements the exponential retransmission mechanism of lost messages. This study investigates the problem and proposes three approaches to reduce call setup delays for VoWLAN applications. Simulation results demonstrate that the proposed mechanisms reduce call setup delays significantly for low-power VoWLAN devices.

Original languageEnglish
Title of host publication2006 3rd IEEE Consumer Communications and Networking Conference, CCNC 2006
Pages380-384
Number of pages5
DOIs
StatePublished - 3 Oct 2006
Event2006 3rd IEEE Consumer Communications and Networking Conference, CCNC 2006 - Las Vegas, NV, United States
Duration: 8 Jan 200610 Jan 2006

Publication series

Name2006 3rd IEEE Consumer Communications and Networking Conference, CCNC 2006
Volume1

Conference

Conference2006 3rd IEEE Consumer Communications and Networking Conference, CCNC 2006
CountryUnited States
CityLas Vegas, NV
Period8/01/0610/01/06

Keywords

  • Low power
  • Session initiation protocol (SIP)
  • Voice over WLAN

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