What is the meaning of peak to average power?

[udit]

peak to average power

what is the meaning of peak to average power? why is it said that the peak to average power of ofdm is higher as compared to single carrier modulation?
what is the effect of having high value of peak to average power.

 

[Aya2002]

Re: peak to average power

A special characteristic of an OFDM signal is that it consists of a number of independently modulated
subcarriers which have different amplitudes and phases. These subcarriers occupy different
spectra in the frequency domain and are transmitted at the same time. When those subcarriers are
added up coherently, the instantaneous peak power of an OFDM signal will be much bigger than
the average power, resulting a large peak-to-average power ratio (PAPR). In the worst case, when
the N signals are added with the same phase, they will produce a peak power that is N times the
average power.

If a nonlinear power amplifier is used to boost OFDM signals, the large peak
power brings about its nonlinearity, which creates out-band signal emission and in-band distortion
and significantly degrades performance

now you can deduce the difference between single carrier and multicarrier systems

enjoy