A Novel Optimized Scheduler to Provide QoS for Video IP Telephony over Wireless Networks

Voice and video over IP (VVoIP) applications are becoming very popular in Wi-Fi enabled portable/handheld devices, because of recent technological advancements and lower service costs. Video IP telephony service (an enhanced service of voice over IP (VoIP)) and video conferencing over IP networks are good examples of modern IP applications. Different from normal voice & video streaming, these applications demand symmetric throughputs for upstream and downstream. Existing Wi-Fi standards (e.g. IEEE 802.11e EDCA) however fail to provide symmetric throughput due to traffic bottleneck at access points. In this paper, we introduce a new real-time data performance attribute called IP traffic symmetry ratio (IPSR) and use IPSR to propose a round-robin scheduler with minimum overheads for video IP telephony and other similar applications. We refer to this scheduler as TI-MAC (Traffic Intelligent - MAC). The scheduler has been implemented and tested in actual hardware, and compared against IEEE 802.11e EDCA. The proposed scheduler shows significant improvements over existing standards by supporting more number of stations with strict QoS criteria.