An efficient HCCA scheduler for video streaming with QoS support

Abstract

Abstract: The 802.11e Task Group has established to enhance Quality of Service (QoS) provision for time-bounded services in the current IEEE 802.11 Medium Access Control (MAC) protocol. The QoS is introduced throughout Hybrid Coordination Function Controlled Channel Access (HCCA) for the rigorous QoS provision. In HCCA, the station is allocated a fixed Transmission Opportunity (TXOP) based on its TSPEC parameters so that it is efficient for Constant Bit Rate streams. However, as the profile of Variable Bit Rate (VBR) traffics is inconstant, they are liable to experience a higher delay especially in bursty traffic case. In this paper, we propose an integrated solution called Adaptive Feedback-based HCCA (AF-HCCA) for supporting video stream that shows the variability on both packet size and generation interval. The AF-HCCA improves both polling and TXOP assignment mechanisms which efficiently schedules the TS based on their actual need. Simulation experiments have been conducted to show that the proposed scheduler not only enhances the packet delay, but also improves the channel utilization by mitigating the over-pollling issue.