Simulation Study And Analysis On Theory And Application Of Turbo Codes

Turbo codes is regarded as landmark of coding theory by reason of approaching Shannon bound. Many researchers pay lots of enthusiasm in Turbo codes, and Turbo codes is becoming one of the hottest point of research in the coding field.A systematic analysis of Turbo codes has been given in this thesis, the contents of research are as follows:The basic structures and principles of encoder and decoder of Parallel Concatenated Convolutional Codes(PCCC) and Serial Concatenated Convolutional Codes(SCCC) are introduced in detail. in current time, comparison between PCCC and SCCC is often under low number of memory in component convolutional codes, so performance comparison between PCCC and SCCC with the high number of memory in component convolutional codes over AWGN channel is investigated through simulation, and the performance comparison between Turbo codes and SCCC is carried out. Simulation results show that when high number of memory, the Turbo codes schemes give a very good performance compared to SCCC schemes. However, at high SNR performances of SCCC is better and avoid the floor effect, a disadvantage of Turbo codes.BCJR algorithm, SOVA algorithm, MAP algorithm, Max-Log-MAP algorithm and Log-MAP algorithm are discussed in particular. The influences of decoder algorithm, interleaver length and iterative number to performance of Turbo codes are carried out by simulation.the principle of interleaver technology of Turbo codes is introduced in detail, especially the influence of interleaver to system performance of Turbo codes is discussed. Two design principles of interleaver are also are put forward, several typical interleavers' basic principles and characteristics are analysed, and gives theoretical analysis of the new methods of application to interleaver design. at last performances of several interleavers to Turbo codes are carried out by simulationTwo methods of analysing the bound of Turbo codes is discussed in detail, and the application of Turbo codes for mobile communication is introduced in detail.This thesis introduces the Turbo codes technology into the error-correcting system of DVB-T. the performance is investigated between standard DVB-T and improved DVB-T through simulation, the simulation result shows that the error-correcting performance of improved DVB-T is better than standard DVB-T's.Although research of Turbo Codes continues, there are still many problems unsolved.great effort for Turbo Codes will be done to problems by researchers...