Automatic Identification And Research Of Modulation Mode Of Wireless Communication Signals

Wireless communication signal recognition technology is an important direction in signal processing research,and has been widely used in both civil and military categories.In particular,with the spread of wireless communication devices,monitoring of wireless communication signals has become increasingly important.This paper records work of software design theory and hardware simulation,and studies the automatic recognition technology of modulation mode in the field of radio signal monitoring.Firstly,the subject uses MATLAB software to carry out theoretical simulation,select the high-order cumulant feature and instantaneous parameter feature of the signal as the distinguishing point study,and discuss the three parts of preprocessing,feature extraction and classifier in the recognition process.The emphasis is on comparing the recognition performance differences between the high-order cumulant eigenvalue algorithm and the instantaneous eigenvalue algorithm.The simulation analysis shows that for the modulated signal in low noise environment,the instantaneous eigenvalue algorithm has a small amount of calculation,simple implementation and more advantages.For the modulated signal in high noise environment,the high order cumulant algorithm has higher recognition performance.It is more conducive to the identification and classification of signals.Secondly,in order to test and preview the theoretical algorithm,this project constructs a system scheme based on FPGA hardware verification platform.Due to the limited FPGA resources,the algorithm needs to be improved.Therefore,the orthogonal demodulation method is adopted to extract the instantaneous frequency domain characteristics of the modulated digital signal.At the same time,the wireless transmitting link and the wireless receiving link have been layout and built.Test signals verify system's function and performance.This topic starts from theoretical simulation.Firstly,the feasibility of the modulated signal recognition algorithm is demonstration.After relying on the FPGA high-speed digital signal processed platform,the hardware test system is layout and seven kinds of conventional modulations such as 2ASK,4ASK,2FSK,4FSK,BPSK,QPSK and 16QAM are verified through experimental data.The signal can be quickly identified in the system:the time required for the modulation signal recognition is less than 0.1 seconds;the FPGA as the main digital processing unit has a chip resource consumption rate of less than 40%.Finally,through the in-depth analysis of the system test results,the feature data is provided for the subsequent higher precision data processing technology.