Turbo Code And Its Related Technologies, Applications And Simulation

Shannon's theorems have proved that random code is a kind of perfect code, but its decoder is complex. So, random code is mostly regarded as a method of analyzing and proving theorem of coding. Until 1993, discovery of Turbo code attracted most researchers'attention. It settles basic of application study of random code.This thesis is concerned about Turbo encoding and decoding, analyzing the theory of it, researching and simulating the performance of it, giving an improved method of using Turbo-OFDM to avoid its disadvantages in fading channel and verifying the analysis and conclusions. The main jobs as following:Firstly, research component of Turbo code: component code, interleaving and puncture, tell conditions which can affect capability of Turbo coder and analyze how they affected. Secondly, explain structure of Turbo decode algorithm: MAP algorithm, Log-Map algorithm, MAX-Log-Map algorithm and SOVA Algorithm. Meanwhile, their advantage and disadvantage are Compared and summarized.Thirdly, Turbo coder and decoder in AWGN channel condition is been simulated. According to compare the result of simulation, analyses of Turbo decoder parameters are done. Meanwhile, according to practice, bring forward own analysis and suggestion about preferences. And the analysis and conclusion are verified on ARM platform.Fourthly, for disadvantage of Turbo code in the fading channel, a kind of improved Turbo code, Turbo-OFDM, is been introduced. A detailed analysis of OFDM principle and effect of Turbo code in fading channel is carried out. Further more, a Rayleigh fading channel module is built to help simulating and analyzing.In the end, prospect and importance of improvement of Turbo code are given both in algorithm and hardware field.