Effects of nonlinear high power amplifier on the area covered by WiMAX signal

In this paper we analyze the effects of nonlinear high power (HPA) amplifier on the area covered by WiMAX signal and nonlinearity impact on the capacity of the WiMAX system assuming the uniform spatial distribution of users. The link degradation due to nonlinear amplifier in line of sight (LOS) channel and two channel models, SUI 4 and SUI 5, for multipath propagation is estimated first. The results obtained are the input for further analysis of the nonlinearity effects on the area covered by the WiMAX signal and the system capacity. It was found out that the coverage area is not seriously reduced due low sensitivity of BPSK and QPSK signals on the nonlinearity, while the significant decrease in the system capacity is observed, because of the rise in BER of higher level modulation schemes caused by nonlinearity.