A Packet Scheduling Scheme for Audio-Video Transmission with IEEE 802.11e HCCA and its Application-Level QoS Assessment

This paper proposes a new scheduling scheme for audio-video transmission with HCCA of the IEEE 802.11e MAC protocol. In the proposed scheduling scheme, the hybrid coordinator (HC) first calculates transmission opportunity (TXOP) duration in a service interval (SI) for each wireless station on the basis of its mean data rate; it then adds additional TXOP for each wireless station which had audio or video packets in its source buffers at the end of the previous TXOP. By simulation, we compare application-level QoS of the reference scheduler in the IEEE 802.11e draft standard and the proposed scheme. Numerical results show that the proposed scheduling scheme outperforms the reference scheduling scheme in video quality and inter-stream media synchronization quality under low traffic conditions.