Peak-to-average power ratio and power amplifier back-off requirements in wireless transmissions

There is a need to relate the peak-to-average power ratio (PAPR) of a single carrier QPSK modulated waveform to the amount of back-off needed in a power amplifier (PA) in relation its 1-dB output compression point for the transmission of the waveform in the most efficient and cost effective way whilst meeting the out-of-band (OOB) spectral emission and bit error rate (BER) specifications. The concept of baseband and passband PAPR is defined and the complementary cumulative distribution function (CCDF) curve of the PAPR distribution is used in this paper to determine the back-off required for acceptable OOB and BER performance. The effect of root raised cosine filtering on the PAPR of QPSK waveform is also studied.