Measuring the Quality of VoIP Traffic on a WiMAX Testbed

The large coverage of the IEEE 802.16 standard, widely known as WiMAX, represents a key advantage compared to several first mile solutions proposed so far, while ensuring a rather inexpensive equipment at the subscriber side. The IEEE 802.16 standard, in practice, promises to be a flexible solution especially where cabling is not a viable choice, or as an alternative to customary leased lines. Nevertheless, modern requirements to wireless connectivity include mandatory QoS guarantees for a wide set of real-time applications, and this is the case of the ever growing trend of VoIP calls. To this aim, WiMAX supports natively real-time traffic. In this paper, we report the results of a set of measurements performed on the field on a WiMAX Alvarion testbed, located in Turin, Italy. We fed the system with synthetic VoIP traffic, real-time guaranteed, competing with concurrent best effort traffic. We obtained E-model figures, thus characterizing the operation intervals of the system, depending on the codec source and on the number of calls.