Scheduling for Next Generation WLANs: Filling the Gap between Offered and Observed Data Rates
Çiftçioğlu, Ertuğrul Necdet and Gürbüz, Özgür (2008) Scheduling for Next Generation WLANs: Filling the Gap between Offered and Observed Data Rates. (Submitted)
In wireless networks, opportunistic scheduling is used to increase system throughput by exploiting multi user diversity. Although recent advances have increased physical layer data rates supported in wireless local area networks (WLANs), actual throughput realized are significantly lower due to overhead. Accordingly, the frame aggregation concept is used in next generation WLANs to improve efficiency. However, with frame aggregation, traditional opportunistic schemes are no longer optimal, since users with better links are frequently served, causing small queue sizes and low efficiency. In this paper, we propose schedulers that take queue and channel conditions into account jointly, to maximize throughput observed at the users for next generation WLANs. We also extend this work to design two schedulers that perform block scheduling for maximizing network throughput over multiple transmission sequences. For the block schedulers which make decisions over long time durations, the evolution of the overall process has been estimated by modelling the system using queueing theory and users’ temporal access proportions are determined. Through detailed simulations, we show that all our proposed algorithms offer significant throughput improvement, better fairness and much lower delay compared with traditional opportunistic schedulers, facilitating the practical use of the evolving standard for next generation wireless networks.
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