Supporting multimedia streaming and best-effort data transmission over IEEE 802.11e EDCA

As demand for broadband multimedia wireless services increases, improving quality of service (QoS) of the widely deployed IEEE 802.11 wireless LAN (WLAN) has become crucial. To support the QoS required by a wide range of applications, the IEEE 802.11 working group has defined a new standard: IEEE 802.11e. In this paper, we propose a measurement-based dynamic media time allocation (MBDMTA) scheme combined with a concatenating window scheme to support real-time variable bit rate (rt-VBR) video and best-effort (BE) data transmission using IEEE 802.11e enhanced distributed channel access (EDCA). To provide the QoS guarantee for rt-VBR video, the proposed MBDMTA scheme dynamically assigns channel time to the rt-VBR video based on the estimate of the required network resources. On the other hand, the concatenating window scheme controls the contention window (CW) ranges of different priority flows such that real-time services always have higher channel access probability, thus achieving the capability of preemptive priorities. In addition, the concatenating window scheme preserves fairness among flows of the same class and attains high channel utilization under different network conditions. Simulation results demonstrate that the throughput and delay performance improve significantly for the transmission of rt-VBR video and BE traffic as compared to those for the 802.11e EDCA specification. It is also revealed that combining the two proposed schemes provides seamless integration and reliable transmission of digital video and data service within the 802.11e EDCA framework.