  Due to its large coverage area, low cost of deployment and high speed data
rates, WiMAX is a promising technology for providing wireless last-mile
connectivity. Physical and MAC layer of this technology refer to the IEEE
802.16e standard, which defines 5 different data delivery service classes that
can be used in order to satisfy Quality of Service (QoS) requirements of
different applications, such as VoIP, videoconference, FTP, Web, etc. The main
aim of the paper is to examine a case of QoS deployment over a cellular WiMAX
network. In particular, the paper compares the performance obtained using two
different QoS configurations differing from the delivery service class used to
transport VoIP traffic, i.e. UGS or ertPS. Results indicate that for
delay-sensitive traffic that fluctuates beyond its nominal rate, having the
possibility to give back some of its reserved bandwidth, ertPS has the
advantage to permit the transmission of BE traffic.
