Research Of Blind Recognition And Classification Methods Of Forward Error Correction Code

Recognitions and classifications of forward error correction code is a important research field in information theory.That is recognising the forward error correction code type from the receiving data stream according to the difference features of each forward error correction code with no prior knowledge about the object.Therefore,It is the main attempt of this paper to study the following two problems.The first one is the classifications code type.To obtain the important information,recognition and classification technique of the code type must be realized firstly.And then the receiver can correctly receive,decode and understand the intercepted data.The other one is link adaptation in intelligent communications To the link adaptation,a transmitter needs to select forward error correction code types to realise stable data transmission.So the receivers should recognize the forward error correction code type for the intercept and capture data.Therefore,this paper mainly considers the application of information countermeasure and link adaptation technology.1.Recognition of frame synchronization parameters.The frame synchronizations is used for communication systems.The recognition of frame synchronization parameters is a important issue.This paper firstly propose novel methods based on auto correlation function to analyze the frame length and beginning positions.The methods are also extended to soft decision situations.What is more,in this paper,a novel method is proposed forr the analysis of no frame synchronizations systems.2.Recognition of important forward error correction code type.The forward error correction code is a important part of channel code.Therefore,the recognition and classification of forward error correction code hold an important status in the channel code recognition field.This paper mainly research on several important forward error correction code type,including linear block code,convolutional code and turbo code.According to the previous research by scholar and the demand of blind identification,the algorithm based on the rank characteristic of code matrix is proposed to realise the classifications of forward error correction code type.Moreover,the code matrix uniformization rank difference function is proposed to realise the integrated automation classifications of forward error correction code type.In order to enhance the accuracy of classification algorithm under low signal to noise ratio environment,taking advantage of code matrix soft information,the algorithm based on probability iteration Gaussian elimination and Walsh-Hadamard transformation is proposed.3.Recognition of linear block codes type.The linear block codes have been widely used in most communication systems.The recognitions and classifications of binary Bose-Chaudhuri-Hocquenghem(BCH)code,Reed-Solomon(RS)code and Low Density Party Check(LDPC)code are researched in this paper.According to the encode rule of various linear block codes,exploring the characteristic of every linear block code as mentioned above,classifications rule for the codes are obtained.Firstly,according to the root continuity of binary BCH code,the binary BCH code classification based on root statistics is proposed.Secondly,according to the frequency domain characteristic of RS code,the RS code classification based on Galois domain frequency characteristic is proposed.Finally,according to the sparse characteristic of LDPC code,the LDPC code classification based on check matrix sparsification is proposed.4.Adaptive recognition of forward error correction encode system.Adaptive modulation and coding technology is the development tendency of communication systems,the adaptive recognition and matching technology of orward error correction encode system is researched is this paper.To enhance the matching accuracy,the forward error correction encode system is divided into two parts.One is linear system and the other one is nolinear system.The matching algorithm based on posterior probablity is proposed for the binary linear forward error correction encode system and the matching algorithm based on check equation posterior probablity is proposed for turbo code system.And the matching algorithm for multi-system is proposed for the first time.