An Adaptive QoS Based Video Packet Transmission Technique for IEEE802.11ac WLAN

With the increasing demand of video services in different application domains including the smart city; it is necessary to offer appropriate QoS support for HD (High Definition) video services on WLAN networks. The IEEE802.11ac is one of the recent WLAN standards which was developed to support high data rate services. The MAC layer of the 802.11ac standard support several advanced features including the TXOP (Transmission Opportunity) to minimise collision levels to improve the QoS of high priority services. In this paper we propose a new adaptive TXOP packet transmission technique which adapts the TXOP period based on the flow rate and congestion levels experienced by video terminals. The proposed flow rate adaptive TXOP algorithm referred as the FRA-TXOP that allocates network transmission resources to each video terminal to improve its QoS and to reduce the overall network congestion level. The FRA-TXOP algorithm also reduces the contention level thus improving the spectrum utilisation of the IEEE 802.11ac WLAN. Simulation results show that the proposed FRA-TXOP algorithm significantly improve the QoS of video traffic as well as increasing the network throughput compared to the fixed TXOP packet transmission technique supported by the IEEE802.11ac MAC protocol.