An Efficient Queue Status Report Mechanism for QoS Guarantee in WLANs

• Main Author: 楊鈞傑
• Other Authors: 李程輝
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/08093947578956503764

碩士 === 國立交通大學 === 電機學院通訊與網路科技產業專班 === 97 === HCF Controlled Channel Access (HCCA), defind in the IEEE 802.11e document, proposes a sample scheduler to allocate transmission opportunity (TXOP) to QoS-aware stations (QSTAs). Since the calculation of TXOP duration is based on the 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 before transmitting packets, each QSTA can be allocated the transmission opportunity (TXOP) based on the deadline of its buffered packets. To satisfy all requested delay bounds, timely queue status reports cause considerable overheads and thus, lead to inefficient bandwidth utilization. In this paper, we adopt multi-polling technique, earliest deadline first policy (EDF) and propose an overhead efficient queue status report scheme to provide QoS support. Simulation results show that our proposed mechanism can not only meet the QoS requirements but also manage the bandwidth more efiiciently in comparison with previous works.