Simulation and modeling of amplifier nonlinearities with 16-QAM modulated waveforms in wireless communication systems

Amplifier nonlinearities impact the performance of both multicarrier CDMA and FDMA wireless communication systems. It is important to accurately model high power amplifiers to predict the bit error rate performance of multicarrier communication systems. This paper provides simulation results on the symbol error rate and bit error rate in the presence of both receiver noise and distortion caused by the amplifier. More specifically, the effects of the amplifier nonlinearity on the communication performance are presented when the input to the amplifier is comprised of a number of band limited QAM amplifier signals. The band limiting of the QAM signals is achieved with an overall filter, including both the transmit and receive filters, having a raised-cosine amplitude response. Such a band limiting process, however, results in additional amplitude variation of the filtered signals, which makes the problem of distortion caused by the nonlinear amplifier even more significant.