A QoS enabled WiFi AP
Padraig O Flaithearta, Hugh Melvin, Michael Schukat · 2014
WiFi-enabled mobile devices such as smartphones and tablets are being increasingly used by both personal and business users for Voice over IP (VoIP) communications, while also supporting conventional data applications such as email, file transfer and web access. Previous research has shown that time synchronized endpoints can provide better QoS by utilizing the Real-time Transport Control Protocol (RTCP) Sender and Receiver Reports (SR/RR) to calculate accurate Mouth to Ear (M2E) delays. The IEEE 802.11e protocol extends 802.11 by providing different traffic priorities based on traffic type. However it cannot distinguish between traffic streams within the same category. In this paper we propose an Access Point (AP)-centred mechanism for further distinguishing between streams within 802.11 categories. It is based on calculating E-Model R-factors for multiple VoIP sessions from delay values that are calculated using RTCP packet information. We detail a real world test-bed and present initial results that correlate well with a previous NS-3 based implementation.