Turbo Codes Algorithm And Practical Research

Turbo codes, which was proposed by French Berrou in Icc'93, is a parallel concatenation code by use of iterative decoding. The simulated result shows: if the size of random interleave is 65536, and iterative decoding repeats 18 times, when Eb/No>0.7dB and rate is 1/2, Bit error of the turbo codes is lower than 10-5, nearly Shannon limits. The performance of turbo codes is so excellent that it has been paid attention to by mobile communication field. In the third generation mobile communication system, unreal time system has frequently used turbo codes. So turbo codes is considered the great technical result after TCM in channel theory and technology. This paper mainly introduces the method of encoding and decoding, analyzes the interleaver through a lots of simulation, proposes an improved method of decoding and some VHDL design of turbo codes.This paper falls into four chapters. The first chapter introduces communication systenu mobile communication system and error control system; the second chapter explains in great detail the normal method of encoding and decoding, compares some algorithmic performance and introduces the new development of turbo codes. The third chapter introduces the simulated method, shows a lot of methods of interleaver, compares these performance and analyzes the cause, compare otherparameter's influence, proposes an ameliorative decoding arithmetic; The four chapter introduces the EDA and proposes the VHDL method of some structure in turbo code, mainly about interleaver and encoding.