Delete The Nature Of Blind Identification Of The Convolutional Code

As the research of the error-correction coding theory going deep, the error-correction code has been widely applied. As the very important error-correction code of all kinds, convolutional codes have been adopted by most communication system. Forthermore it can be applied in other field.We all know reliability and velocity are always conflict and communication will face the following situations: 1) Both the noise and disturbance change as time varies when information is transmitted; 2) The bandwidth also changes as time varies. So how to efficiently utilize the finite bandwidth to realize the high efficiency, high reliability communication is an important topic to study. Adaptive modulation and coding by using convolutional codes is a key technology to solve the above problem.First, this paper studies a special class of convolutional codes ?punctured convolutional codes and the blind recognition problem of punctured convolutional codes, that is determining minimal basic encoding matrices and puncturing patterns according to the accounted parity check matrices of the punctured convolutinal codes. The main advantages: 1) Studying the properties of the punctured convolutional codes, especially the degree property of the generator matrix. 2) Proving a very important equivalence property of punctured convolutional codes. We give an equivalent partition of puncturing patterns. Then we show that equivalent puncturing patterns deduce equivalent punctured codes. 3) Solving the blind recognition problem of punctured convolutional codes. We present an algorithm to recognize minimal basic encoding matrices and puncturing patterns, and realize adaptive modulation and coding. Our result can also be applied to the field of signal processing, communication interception, and so on.Second, this paper researches the application of convolutional codes in the cryptanalysis. We improve the method [40]. The main advantages: 1) Describing how to search the LFSR feedback polynomials by combining and enumerating, and renew the LFSR's initial states by using the correlation attack via convolutional codes. 2) Improving the traditional Viterbi algorithm. 3) Proposing approach of the offline searching and the online decoding, and the approach was very valuable in practice.