Selectivity function scheduler for IEEE 802.11e HCCA access mode

Abstract

SUMMARY In this paper, we present a scheduling algorithm that enhances the performance of the standard IEEE 802.11e scheduler for the Hybrid Coordination Function Controlled Channel Access mode. The main contribution in designing the proposed scheduler is the ability to accommodate multiple streams with different levels of Quality of Service requirements concurrently running on the same station. This is achieved by dynamically calculating the Transmission Opportunities of each active traffic stream (TS) and the appropriate Service Interval of each active station. The proposed algorithm optimizes the utilization of the scarce bandwidth resources by only polling active stations. The algorithm incorporates a selectivity function to assign polling priorities to the active streams only based on their diverse requirements and their link‐attainable transmission rates. The performance of the proposed Selectivity Function Scheduler (SFS) scheme is evaluated against the standard scheduler. Simulation results show that the SFS outperforms the standard scheduler in terms of enhancing streams' throughput, reducing packet dropping ratio and maintaining high fairness amongst the admitted TS. Copyright © 2011 John Wiley & Sons, Ltd.

Adaptive multi-polling scheduler for QoS support of video transmission in IEEE 802.11e WLANs

“…However, these enhancements are still not sufficient to cope with the fast fluctuating nature of highly compressed video applications since the QSTAs are scheduled according to an estimation about the uplink TSs characteristic which may be far from the real traffics. Although, some other approaches such as [2,7,19,20,47] have been focused on enhancing the polling overhead of HCCA scheduler, there was a lack of consideration for transmitting prerecorded streams in WLANs.…”

“…where n is the number of admitted TSs and M SI i is the maximum SI of the i th stream. The SI is computed so that it satisfies the condition in Equation (2).…”