光OFDM系统中削波噪声的建模与研究

Modeling and research on clipping noise in optical OFDM systems

针对光正交频分复用(OFDM)系统中峰值平均功率比(PAPR)较高的缺点,研究了削波法降低PAPR的原理;根据这一原理,通过大量数据分析计算,建立了基于MQAM调制下光OFDM系统中的削波噪声模型;由所建立的模型,直接计算得出不同调制下光OFDM系统削波后的误符率。仿真结果表明,每种进制调制下,根据本文建立的削波噪声模型与OFDM具体系统模型仿真所得到的两条曲线基本吻合,并且这两条曲线在不同削波比下的最大均方误差(MSE)不超过1.26×10-2。这充分论证了所建立的削波噪声模型的可行性与适用性。

According to the problem of the high peak-to-average power ratio （PAPR） in optical orthogonal frequency division multiplexing （OFDM） systems,the principle of PAPR reduction method by clipping is studied. Based on this prineiple,a clipping noise model of optical OFDM systems in the MQAM modulation is established by analyzing and computing a large number of data. According to the established model,the error-symbol-rates of optical OFDM systems in different modulations can be directly calculated after clipping. The simulation results show that the curve of the established clipping noise model agrees well with that of the simulation model of optical OFDM systems in different modulations. Furthermore,the maximum value of the mean square error （MSE） between the two curves in different clipping ratios is not more than 1.26 × 10-2 ,Which demonstrates the feasibility and applicability of the established clipping noise model.