Title: A novel scheduler for VBR traffic in IEEE 802.11 HCCA WLANs

Authors: Yaw-Wen Kuo, Jin-Hsiu Tsai

Addresses: Department of Electrical Engineering, National Chi Nun University, Nantou 54561, Taiwan. ' Department of Electrical Engineering, National Chi Nun University, Nantou 54561, Taiwan

Abstract: IEEE 802.11 standard provides a reference scheduler with admission control, which is suitable for CBR traffic because the allocation of Transmission Opportunity (TXOP) duration is only based on the mean data rate. This paper proposes a novel scheduler for Variable Bit Rate (VBR) traffic, where the polling list and TXOP values are dynamically updated according to the current backlog and the measured loss rate of each flow. Moreover, an effective admission method is also provided as well to guarantee the loss rate. According to our simulation results, the number of admitted flows in the proposed scheduler is close to that in the reference scheduler and the loss rate can be well controlled below the threshold.

Keywords: HCCA WLANs; QoS; quality of service; scheduling; wireless LANs; local area networks; variable bit rate; VBR; simulation; flow loss rate; admission control; hybrid coordination function; HCF controlled channel access.

DOI: 10.1504/IJAHUC.2011.042350

International Journal of Ad Hoc and Ubiquitous Computing, 2011 Vol.8 No.3, pp.165 - 173

Received: 23 Feb 2010
Accepted: 30 Apr 2010

Published online: 05 Sep 2011 *

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