基于高阶累积量的OFDM子载波盲识别探讨

正交频分复用（OFDM）技术作为一种特殊的多载波调制技术，以其高效的频谱利用率、较强的抗码间干扰能力等优点成为第四代宽带技术的核心技术之一。同时，OFDM的广泛应用也为信息对抗、无线频谱资源管理等领域带来了一系列新的任务与挑战。因此，对非合作OFDM信号侦收技术的研究，意义深远。 由于OFDM调制方式的特殊性，在完成宽带多载波与单载波信号分类之后，接收系统有必要对OFDM信号的子载波类型进行进一步判断。文中采用基于高阶累积量的子信道调制盲识别算法作为技术路线，通过提取特征向量实现对子信道调制方式的盲识别。 在基带OFDM信号子载波调制类型识别部分，结合OFDM系统的等效标量模型，利用每个子载波上符号序列的统计特性，提取序列的高阶累积量作为识别分类特征构造算法，能够有效地抑制多径衰落所引起的功率衰减以及相位旋转对子载波调制类型识别性能的影响，结合仿真实验，我们分析了所提出算法的高效识别性能。

To investigate the OFDM sub carrier blind identification based on higher order cumulants

Orthogonal frequency division multiplexing（OFDM）is a special multi carrier modulation technology,because of its high spectrum utilization rate, the advantages of strong anti interference becomes one of the core technology of the fourth generation of broadband technology. At the same time, the wide application of OFDM has also brought a series of new tasks and challenges in the area of information warfare, the wireless spectrum resource management.Therefore, research on non cooperative OFDM signal collection technology,far-reaching significance. Because of the particularity of OFDM modulation,after the completion ofbroadband multi carrier and single carrier signal classification,the receiving system is necessary to sub carrier type on OFDM signals are further judgment.In this paper,based on the high order cumulant sub channel blind modulation recognition algorithm as the technical route,by extracting feature vector to achieve blind modulation recognition of sub channel. In the baseband OFDM signal modulation type identification part,based on the equivalent scalar model of OFDM system,using the statistical characteristic symbol sequence of each sub carrier,high order cumulant sequence ofidentification as a classification feature extraction algorithm,can powereffectively suppress multi-path fading effect caused by attenuation and phase rotation of sub carrier modulation type recognition performance,combined with simulation experiments,we analyzed the recognition performance of the proposed algorithm is efficient.