Research On The Modulation Identification And Parameter Estimation Of OFDM Signal

The communication technology has been developing rapidly in the past decadesand a variety of wireless communication systems have been widely used in the militaryand civil fields. There are more and more modulation techniques today and are muchsophisticated than before. OFDM is one of the multi-carrier modulations and is a keytechnology in the fourth generation mobile communication system. Due to its advantageof high spectrum utilization rate and low symbol interference, OFDM has a widely usein wireless communication systems. There is a widely demand for signal modulationidentification and parameter estimation in electronic surveillance systems, militarycommunication and interference identification. Thus this paper focus on the research ofmodulation identification of OFDM signal.First, a novel algorithm for recognition of OFDM signal based on wavelettransform is proposed in this paper. It has a better recognition effect even in low SNRconditions. Second, using the fact that the OFDM is asymptotically Gaussian this paperpropose a detector based on High-order Cummulant. Experiments show that this methodhas well performance in the discrimination of OFDM and single carrier digital signalswith low computation. Finally, the study of estimation of symbol rate and subcarrierfrequency of OFDM is discussed in this article.