IP QoS support in IEEE 802.11b WLANs

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Abstract

This paper addresses the support of IP with Quality of Service (QoS) in IEEE 802.11b WLANs. Both the Distributed Coordination Function (DCF) and Point Coordination Function (PCF) modes of operation are analysed and compared. For DCF, both the original standard and some of the enhancements proposed for IEEE 802.11 e are considered. For PCF, two alternative scheduling disciplines are considered: Scheduling based on Estimated Transmission Times (SETT) proposed by the authors and Weighted Deficit Round Robin (WDRR). It is shown that while WDRR is suitable to perform fair bandwidth distribution, SETT also takes into account maximum transmission delay and service priority. Simulation results show that DCF cannot be used to support IP QoS even if 802.11e enhancements are used. On the other hand, PCF performs better with SETT than with WDRR. SETT is able to keep a similar level for network utilisation, while fulfilling the QoS requirements of real-time services such as packet telephony and videoconference, even in the presence of lower priority bursty data. The impact of the high overhead introduced by the IEEE 802.11 PHY and MAC layers was also evaluated, showing that for small packet traffic such as Voice over IP traffic, advanced voice compression is of limited usefulness. C 2003 Elsevier B.V. All rights reserved.

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• IP QoS support in IEEE802.11b WLANs. (deposited 01 Feb 2007 18:50)
  • IP QoS support in IEEE 802.11b WLANs. (deposited 19 Jun 2008 14:19) [Currently Displayed]