Research And Implementation On Blind Recognition Of CPM Modulation And Channel Coding

In a non-cooperative communication system, since the received modulated signal has noise interference, the receiver needs to demodulate and decode the signal to get the information sequence. In addition, any prior knowledge of the signal is unknown, blind recognition of modulation type, modulation parameters, channel coding type and coding parameters is necessary for the receiver. In this thesis, the blind recognition of CPM modulation parameters, BCH coding parameters and the channel coding type are investigated. Further simulation realization via C language is also presented.The main works are as follows:(1) Based on the study of expression and cyclic-stationary characteristic of CPM modulation signals, we investigate the blind recognition algorithm to identify CPM modulation parameters without using the auxiliary data. Such a recognition method can achieve the jointly blind recognition processing of the modulation parameters, symbol period and frequency offset of CPM signals.(2) The blind recognition of BCH codes with errors is researched. We firstly consider some individual methods such as linear matrix analysis method, bit-related method, root-based method and common divisor method. Then a complete fault-tolerant blind recognition algorithm of BCH codes is proposed. Linear matrix analysis method and bit-related method are applied to identify the code length. Meanwhile, root-based method on the basis of BCH coding theory is utilized to identify the code start point, the primitive polynomial and the generator polynomial.(3)A blind recognition algorithm of channel coding type with error-free is addressed. Firstly, the coding theory of Convolutional codes, Linear Block codes and Turbo codes is studied. Next, Linear matrix analysis method is used to analyze the relationship between of the three codes. According to the different linear constraints of the row standard simplest form matrix, three features are discovered to identify the coding type, which are the growth ratio of the number of columns to the rank, the distribution rule of zero and one in the diagonal and the existence of parity column. Simulation results show that the algorithm can blindly identify convolutional codes, BCH codes, RS codes and Turbo codes in WCDMA accurately.