The Parameter Estimation Techniques Of Non-punctured Turbo Code

In the digital communication system,in order to ensure the reliability of information transmission,the coding and decoding technology is generally adopted.The original information is restored through demodulated and decoded by the receiver,by analyzing the received signal based on the priori information such as the modulation and coding parameters sent by the partner.However,this method is not feasible for non-cooperative communication because any priori information about the intercepted signal is unknown to the receiver.The modulation and encoding methods of the signal and related parameters need to be recognized first,and lay the foundation for subsequent information processing.The research direction of this subject is blind recognition technology of channel encoding,which is a processing method at the information level.The channel encoding type and encoding parameters are obtained with the absence of priori information,so that the original information can be get through decoding.The technology can be widely applied such as communications reconnaissance and intelligent communications.The investigation of parameter estimation techniques for non-punctured Turbo Code is focuses on in this thesis.Firstly,the research background and significance of this topic is given.The current research status of channel coding recognition technology is analyzed and summarized.The main research contents of this paper and the composition framework is proposed.And the basic principles of Turbo codes are introduced,including the generation principle and punctured patterns of classical Turbo code and dual binary convolutional Turbo code?DB-CTC?in DVB_RCS protocol.Secondly,for the RSC code parameter estimation technology based on LLR algebra,the main existing RSC code recognition algorithm is investigated firstly.Then the recognition basis,algorithm principle and recognition scheme of the selected algorithm are analyzed,and the effectiveness simulation of the algorithm is given.As the core content,the estimation of the constraint length m seriously reduces the whole capability of anti-noise,and thus the whole capability of anti-noise is poor.An improved algorithm is proposed which uses traversal and reverse verification not to estimate the constraint length.The two parameters of the constraint length and the basic generated matrix can be simultaneously recognized.Using theoretical analysis and data simulation methods,the results show that the overall anti-noise performance of the proposed parameter estimation method is effectively improved.Then,for the interleaver parameter estimation technology based on average conformity of parity-check equation,the main existing interleaver recognition algorithm is investigated firstly.Then the recognition basis,algorithm principle and recognition scheme of the selected algorithm are analyzed,and the effectiveness simulation of the algorithm is given.As the core content,an improved algorithm is proposed to overcome the defects that traversing the first two interleaving positions greatly increases the amount of computation.First the first m interleaving positions are estimated by introducing the column vector comparison method,and then the remaining interleaving positions are recognized based on conformity of parity-check equation.Using theoretical analysis and data simulation methods,the simulation results show that the computational complexity of the proposed parameter estimation method is greatly reduced compared with the original algorithm,and still maintains the excellent anti-noise performance of the original algorithm.Finally,the overall recognition scheme is given.The overall recognition scheme for classical Turbo code is given based on the previous research.And the recognition capability is investigated.Then the recognition for DB-CTC in DVB_RCS protocol is investigated.Simulation results demonstrate that the recognition algorithm can be effective at E_b/N₀?3dBand is of great practical application significance.