A Low Overhead Queue Status Report Scheme for QoS Support in WLANs

Abstract

HCF Controlled Channel Access (HCCA), defined in the IEEE 802.11e document, provides a sample scheduler to allocate transmission opportunity (TXOP) to QoS-aware stations (QSTAs). Since the calculation of TXOP duration is based on mean data rate, it is efficient for constant bit rate (CBR) traffic. For variable bit rate (VBR) traffic, however, delay bound of some admitted traffic flows may be violated. Several previous works suggested that, through reporting queue status to schedulers, each QSTA can be allocated sufficient transmission opportunity (TXOP) for its buffered packets to meet delay bound requirement. However, timely queue status reports may cause considerable overheads and lead to inefficient bandwidth utilization. In this paper, we propose a low overhead queue status report scheme based on multi-polling technique and earliest deadline first policy (EDF) to provide QoS support. Simulation results show that our proposed scheme can not only meet the QoS requirements but also manage the bandwidth more efficiently than previous works.