In this paper some WiMAX MAC layer parameters will be optimized to
improve applications performance. The study is aimed to show, via
simulation, the effect of Automatic Repeat Request (ARQ) parameters on
the WiMAX performance. Also, it is aimed to verify the effectiveness of
Unsolicited Grant Service (UGS), Real Time Polling Service (rtPS), and
Enhanced Real Time Polling Service (ertPS) in managing voice traffic and
their effect on data traffic which use Best Effort (BE) service. The results
show that the video delay will be increased by from 5 ms to 24 ms when
enabling ARQ protocol on WiMAX network. It also give the optimum
parameters for ARQ protocol to improve the WiMAX network
performance. The research also shows that the best scheduling service for
voice is UGS; but it reduces the throughput for BE data.