在過采樣條件下，分析了正交頻分復(fù)用系統(tǒng)在不同采樣率時(shí)，信號(hào)峰值平均功率比的統(tǒng)計(jì)特性。按Nyquist采樣率均勻抽取出的采樣點(diǎn)之間相互獨(dú)立同分布，推廣到過采樣系數(shù)為2時(shí)，得到此時(shí)由各采樣點(diǎn)之間相關(guān)系數(shù)構(gòu)成的協(xié)方差矩陣，利用數(shù)值計(jì)算對(duì)其進(jìn)行分析。結(jié)果表明：所有的采樣點(diǎn)之間能近似滿足相互獨(dú)立同分布的關(guān)系，則可以得到此時(shí)信號(hào)峰值平均功率比概率分布的理論計(jì)算公式，并對(duì)此公式進(jìn)行了仿真驗(yàn)證，其理論計(jì)算結(jié)果和實(shí)際仿真結(jié)果吻合。
關(guān) 鍵 詞 正交頻分復(fù)用; 峰值平均功率比; 過采樣; 互補(bǔ)累積分布函數(shù)

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