The IEEE 802.11 working group is currently working on a new standard called IEEE 802.11e to support quality of service (QoS) in WLANs. 802.11e introduces a so-called hybrid coordination function (HCF) containing two medium access mechanisms: enhanced distributed channel access (EDCA) and HCF controlled channel access (HCCA). In the EDCA mechanism, many QoS parameters are introduced including minimum contention window (CWmin), maximum contention window (CWmax), arbitration inter frame space (AIFS) and transmission opportunity limit (TXOPlimit). In this paper, we experimentally assess the MPEG-4 video streaming performance over 802.11e. In particular, we discuss in detail how the human satisfaction of streaming video is affected by the main QoS parameters in IEEE 802.11e WLANs. We measure the level of end user satisfaction together with the network performance and give recommendations regarding the network design and the parameter settings.
['Deyun Gao', 'Jianfei Cai', 'Paul Bao', 'Zhihai He']
MPEG-4 video streaming quality evaluation in IEEE 802.11e WLANs