Research On Non-coherent Demodulation Of Continuous Phase Modulation Signal And Reed-Solomon Code Blind Recognition

In the digital communication system,the signal transmitted in the channel is affected by the noise,and the receiver needs to demodulate and decode the received signal to recover the information.However,for non-cooperative communication,any information received by the receiver is unknown,including modulation mode,modulation parameters,coding mode and coding parameters.Therefore,the receiving side needs to process the received signal in terms of modulation scheme identification,modulation parameter estimation,coding type recognization,and coding parameter identification.The incoherent demodulation algorithm of continuous phase modulation?CPM?signal and blind recognition algorithm of Reed-Solomon?RS?code are studied in this paper.First of all,based on the model,state representation and coherent demodulation of continuous phase modulation signal is introduced,the non-coherent demodulation algorithm of continuous phase modulation signal based on 2-symbol differential correlation is focused on research.And the frequency offset correction factor is introduced to correct the phase offset caused by the remaining frequency offset of the carrier.Secondly,the classical algorithm of RS code blind recognition is studied.The coding principle of RS code and blind recognition method of RS code without error code are introduced,and the basic characteristics of RS code is analyzed.In the presence of error codes,two kinds of classical blind recognition algorithms:Galois Field Fourier Transform and Euclidean algorithms are studied and analyzed.The basis of the Galois field Fourier transform method is that the RS code will have zeros spectrum characteristic after Galois field Fourier transform.However,the amount of data required by the method implementation process is relatively large,and the computational complexity is high.Euclidean algorithm based on the RS code cyclic shift characteristics,to achieve RS code blind recognition.This method avoids the traversal of the primitive polynomials over all codeword lengths and removes some of the RS codewords with errors,and reduces the computational complexity.Finally,based on the method of decomposition of Chinese Remainder Theorem,an improved scheme is proposed,and the recognition performance of the method is simulated.Based on the low data amount and low complexity of the original method of decomposition of Chinese Remainder Theorem,this method improves the recognition performance of the algorithm Based on the algorithm of Chinese Remainder Theorem,the algorithm computes the check column of component code sequence matrix to zero based on the relationship between the information bits and the check bits of the component code.When there are error codes in the code group,there are still more zeroes in the reduced checklist,and there aren't more zeroes in the checklist for random codewords.After recognizing the length of the codewords and the primitive polynomial,the received binary information sequence can be converted into a sequence of RS code words,and Galois Field Fourier transform is performed in the recognition domain.According to the occurrence of zero in the spectral vector Position and number to solve the code sequence generator polynomial.At bit error rate10^-1 and m=3,Galois Field Fourier Transform and Euclidean algorithm can not effectively identify the coding parameters of RS code.However,the improved scheme based on Chinese Remainder Theorem decomposition proposed in this paper can effectively identify the coding parameters of RS codes,and the recognition probability can reach above 70%.