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Proceedings Paper

Comparison of QoS guarantee techniques for VoIP over IEEE802.11 wireless LAN
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Paper Abstract

An emerging killer application for enterprise wireless LANs (WLANs) is voice over IP (VoIP) telephony, which promises to greatly improve the reachability and mobility of enterprise telephony service at low cost. None of the commercial IEEE 802.11 WLAN-based VoIP products can support more than ten G.729-quality voice conversations over a single IEEE 802.11b channel on real-world WLANs, even though the physical transmission rate is more than two orders of magnitude higher than an individual VoIP connection's bandwidth requirement. There are two main reasons why these VoIP systems' effective throughput is significantly lower than expected: VoIP's stringent latency requirement and substantial per-WLAN-packet overhead. Time-Division Multiple Access (TDMA) is a well-known technique that provides per-connection QoS guarantee as well as improves the radio channel utilization efficiency. This paper compares the effective throughput of IEEE 802.11, IEEE 802.11e and a software-based TDMA (STDMA) protocol that is specifically designed to support WLAN-based VoIP applications, on the same commodity IEEE 802.11 WLAN hardware. Empirical measurements from a VOIP over WLAN testbed show that the numbers of G.729-quality voice conversations that IEEE 802.11, IEEE 802.11e and STDMA can support over a single IEEE 802.11b channel are 18, 22 and 50, respectively.

Paper Details

Date Published: 28 January 2008
PDF: 12 pages
Proc. SPIE 6818, Multimedia Computing and Networking 2008, 68180J (28 January 2008); doi: 10.1117/12.775141
Show Author Affiliations
Fanglu Guo, Stony Brook Univ. (United States)
Tzi-cker Chiueh, Stony Brook Univ. (United States)

Published in SPIE Proceedings Vol. 6818:
Multimedia Computing and Networking 2008
Reza Rejaie; Roger Zimmermann, Editor(s)

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