抑制LOFDM系统PAPR非线性压扩变换算法

针对网格正交频分复用(LOFDM,lattice OFDM)系统具有较传统OFDM系统更高峰均功率比(PAPR,peak-to-average power ratio)的问题,在将传统非线性压扩变换应用于LOFDM系统的同时研究并分析了一种新的基于原信号统计分布特性的连续可导非线性压扩算法。该算法从原信号的渐进高斯分布特性出发并对原信号的幅度分布函数进行截断逼近,在保持平均功率不变的条件下,将压扩后的信号限制在与原信号分布特性一致的特定范围内,使压扩后的信号在保持其原有分布特性的同时,能更大程度改善系统PAPR和误比特(BER,biterror ratio)性能。理论分析和仿真实验表明,所提出的算法性能要显著优于传统非线性压扩算法。

Nonlinear companding transform for PAPR reduction in lattice-OFDM system

Since the inherent higher peak-to-average power ratio (PAPR) in lattice OFDM (LOFDM) than that of conventional OFDM systems, a novel effective continuous and differentiable nonlinear companding scheme is investigated and analyzed when employing the conventional companding transforms. By making full use of the characteristic of the Gaussian-distributed original signals and employing a truncation to the distribution function of the original signals, the companded signals can be limited in a specific area which consistents with the distribution of original signals. Therefore, the companded signals can not only achieve an improved PAPR and bit error ratio (BER) performance but also maintain the statistical characteristics of the original signals. Theoretical analysis and simulation results demonstrate that the proposed scheme substantially outperforms the conventional nonlinear companding schemes.