Performance of M-QAM OFDM Systems in the Presence of EVM Degradation

An Orthogonal frequency division multiplexing (OFDM) has been adopted by several wireless transmission standards. The major drawback of OFDM is the large dynamic range of the transmit waveforms making OFDM vulnerable to nonlinearities of the power amplifier (PA) and causing the PA to obtain low power efficiency on the Radio frequency to dc power conversion. The commonly used performance metric to characterize a dynamic range of OFDM signal is peak-to-average power ratio (PAPR). To suppress the nonlinear effects, to reduce the PAPR value. However, this results in the increase ofthe error vector magnitude (EVM) and the decrease of themodulation error ratio (MER). EVM and the MER analysis is useful tool for prediction of thedynamic performance. In this paper, we compare the different performance metrics such as EVM and MER and show that they can be equivalently useful as signal to noise ratio (SNR) and bit error rate (BER).