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Title

VoIP capacity-analysis, improvements, and limits in IEEE 802.11 wireless LAN

Author(s)

Stoeckigt, Kewin O.;  Vu, Hai Le

Abstract

Wireless voice over internet protocol (VoIP) is an important emerging service in telecommunication due to its potential for replacing cell phone communication wherever a wireless local area network (WLAN) is installed. Recent studies, however, suggest that the number of voice calls that can be supported in the widely deployed IEEE 802.11 WLAN is limited. In this paper, we utilize a so-called transmission opportunity (TXOP) parameter of a medium access control (MAC) protocol as a simple solution to improve the VoIP capacity. We provide a detailed analytical model to show that the capacity can significantly be improved and discuss the implications of the TXOP parameter in terms of the maximum number of calls the IEEE 802.11 network can support. The analytical results are validated by simulations for a wide range of parameters. Furthermore, we investigate the impact of the buffer at the access point (AP) on the number of obtainable voice calls. We show that there exists an optimal buffer size where the maximum voice capacity is achieved, but further increasing the buffer beyond this value will not result in an increased voice capacity. Based on this finding, a closed-form expression for the maximum number of voice calls is developed as a function of the TXOP value. Finally, we propose a simple yet accurate approximation for voice-capacity estimation and provide some insights gained from the approximation.

Publication type

Journal article

Research centre

Swinburne University of Technology. Faculty of Information and Communication Technologies. Centre for Advanced Internet Architectures

Source

IEEE Transactions on Vehicular Technology, Vol. 59, no. 9 (Nov 2010), pp. 4553-4563

Publication year

2010

FOR Code(s)

0906 Electrical and Electronic Engineering

Keyword(s)

Buffer size;  EDCA;  Enhanced distributed channel access;  IEEE 802.11 standard;  Transmission opportunity;  TXOP;  Voice-over-internet protocol capacity;  VoIP;  Wireless local area networks;  WLAN

Publisher

IEEE

ISSN

0018-9545

Publisher URL

http://dx.doi.org/10.1109/tvt.2010.2068318

Copyright

Copyright © 2010 IEEE. Published version of the paper reproduced here in accordance with the copyright policy of the publisher. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.

Research Projects

Mechanism design for next generation random access wireless protocols, Australian Research Council grant number DP1095103

Full text

Peer reviewed