过采样下预留载波OFDM系统峰均比抑制方法

Tone reservation method under oversampling for PAPR reduction in OFDM systems

为降低过采样后峰均比回升对预留载波法峰均比抑制效果的影响,提出了一种改进方法。该方法利用改进的互熵法计算预留载波的位置,获得一个过采样条件下旁瓣值最低的时域核。用时域核对过采样后的正交频分复用(OFDM)符号进行迭代削峰处理。每次迭代中,OFDM符号的幅度峰值被加权且循环移位后的时域核削减到一个预先设定的阈值。仿真结果表明,该方法可有效降低峰均比回升的影响,在总载波数1 024,预留载波数10的条件下,峰均比抑制效果改善了2.1 dB。

An improved method was proposed to reduce the deterioration of Peak to Average Power Ratio（PAPR） reduction of tone reservation method due to PAPR rising caused by oversampling. The modified Cross Entropy（CE） method was adopted to calculate the locations of the reserved tones. A time domain kernel with the lowest secondary peak under oversamping was obtained according to the locations. The oversampled Orthogonal Frequency Division Multiplexing（OFDM） symbol was clipped by the kernel iteratively. The sample with the peak magnitude was clipped by the weighted and circularly shifted kernel to a predefined magnitude in each iteration. The simulation results validate the effectiveness of the proposed method, by which PAPR reduction is improved by 2.1 dB under 1 024 total subcarries and 10 reserved tones.