The effects of nonlinear power amplifiers on the of a HiperLAN/2 system

Real-world power amplifiers (PAs) are weakly nonlinear. The nonlinear behavior causes subcarrier intermodulation in OFDM based transmitters. This paper shows the results of simulations performed on a software HiperLAN/2 system with a nonlinear power amplifier model. We show that HiperLAN/2 is much less sensitive to nonlinearities of the PA when BPSK or QPSK modulated sub-carriers are used compared to QAM16 or QAM64 modulated sub-carriers. Both QAM16 and QAM64 require a PA backoff amount of at least 5 dB while BPSK and QPSK don´t require any backoff. This means that BPSK or QPSK modulated OFDM is more power efficient.