在過采樣條件下，分析了正交頻分復用系統在不同采樣率時，信號峰值平均功率比的統計特性。按Nyquist采樣率均勻抽取出的采樣點之間相互獨立同分布，推廣到過采樣系數為2時，得到此時由各采樣點之間相關系數構成的協方差矩陣，利用數值計算對其進行分析。結果表明：所有的采樣點之間能近似滿足相互獨立同分布的關系，則可以得到此時信號峰值平均功率比概率分布的理論計算公式，并對此公式進行了仿真驗證，其理論計算結果和實際仿真結果吻合。
關 鍵 詞 正交頻分復用; 峰值平均功率比; 過采樣; 互補累積分布函數

Abstract Peak-to-average power ratio of orthogonal frequency division multiplexing signals is analyzed when the sampling rate is different. The samples according to Nyquist sample rate in one period of OFDM symbol are independent identically distributed random variables. When oversampling factor is 2, the covariance matrix composed of the coefficients of correlation between those samples can be calculated by numerical method. As a result, all samples in one symbol are approximately independent when oversampling factor is 2. So the probability distribution function of peak-to-average power ratio can be achieved. The results are proved by simulation.
Key words orthogonal frequency division multiplexing; peak-to-average power ratio; oversampling; complementary cumulative distribution function