Experiments of VoIP using WiMAX system and fading simulator with two-path models for aeronautical scenarios

In this paper, we study the performance of VoIP over WiMAX systems. We assume a two-path model for airport surface communications and experiment by using a multipath fading simulator. We evaluate the R-factor when the mobile speed and delay time are changed. We use an R-factor of 80 which is defined in ED-136 as a threshold where VoIP can be used for air traffic control (ATC). When the delay time is 0 -20ns i.e., the horizontal distance is over 40m and if the mobile speed is under 50 km/h, the R-factor is over 80. On the other hand, in takeoff and landing scenarios when the mobile speed is over 300 km/h, it is difficult to keep the quality of VoIP and some improvements in the receiver are needed.