Distribution Bound of PAPR in OFDM Signals

Assuming that the baseband OFDM signal is characterized as a band-limited complex Gaussian process, the distribution of the peak-to-average power ratio (PAPR) in band-limited OFDM signals is investigated in this paper. Based on the level-crossing rate theory, a simple closed-form upper bound on the PAPR distribution of a band-limited OFDM signal is proposed. For the 16QAM-OFDM systems with different subcarrier number, the Monte Carlo simulation of the PAPR distribution is performed to test the tightness of the proposed upper bound. The simulation results show that the proposed upper bound matches the simulation results well when the subcarrier number is greater than or equal to 64. However, the upper bound is not tight when the subcarrier number is 32. In addition, instead of the actual PAPR being directly proportional to the subcarrier number, the research indicates that the probability that the PAPR is greater than a given value gamma is directly proportional to the subcarrier number N. When the subcarrier number is large, the dominant effect is the stochastic behavior of the OFDM signal and also this shows that the stochastic description of PAPR distribution is quite important