IEEE defines various modulation schemes for WiMAX i.e. QPSK, BPSK, 16 QAM and 64 QAM. This model will examine Internet Protocol TeleVision (IPTV) performance over fixed WiMAX system taking many combinations of digital modulation. The performance will involve many key system parameters, which will involve the variation in the path loss, video coding, different rated codes and scheduling service classes in FEC channel coding. The performance study will be carried on by using OPNET modeller.