Dynamic adaptation policies to improve quality of service of real-time multimedia applications in IEEE 802.11e WLAN Networks |
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Authors: | Naomi Ramos Debashis Panigrahi Sujit Dey |
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Affiliation: | (1) Mobile Embedded Systems Design and Test Lab, Department of Electrical and Computer Engineering, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0409, USA |
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Abstract: | With the increased popularity of wireless broadband networks and the growing demand for multimedia applications, such as streaming
video and teleconferencing, there is a need to support diverse multimedia services over the wireless medium. In order to efficiently
address these diverse needs, efforts have been pursued to provide Quality of Service (QoS) mechanisms for medium access, resulting
in a standard called IEEE 802.11e. One of the enhancements proposed in IEEE 802.11e is a polling-based access mechanism, which
is targeted for real-time multimedia flows. In this polling-based scheme, scheduling and time allocation are based on flow
reservations. Hence, the effectiveness of the mechanism is heavily dependent on the accuracy of the flow requirements in the
reservation. Flow requirements, however, can vary over time and an allocation based on fixed reservations cannot address this
variability. This limitation, which is present in the reference scheduler of IEEE 802.11e, leads to degraded multimedia quality
for flows with variable requirements, even when channel resources are available.
In order to address the above limitation, we present an adaptation framework that dynamically adjusts the polling-based access
mechanism and associates flows to different modes of access (polling-based/contention-based), according to the current needs
of the application, as opposed to solely relying on the reservation parameters. We demonstrate that with our adaptation, the
achieved QoS for real-time multimedia streams, in terms of delay and throughput metrics, can be significantly improved compared
to other known mechanisms. Additionally, we show the benefits of our adaptation framework on overall multimedia quality and
system capacity.
This research is supported by the University of California Discovery Grant (com02-10123) and the Center for Wireless Communications
(CWC), University of California, San Diego. |
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Keywords: | IEEE 802 11e Quality of service Video streaming Wireless LAN Service level agreements |
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