Study of Gradient Algorithm for Turbo Product Codes

Turbo Product Codes(TPC) are promising forward error correcting codes,which have serial concatenation structure with two or more liner block coders separated by a simple row-column interleaver.This paper presents a novel soft—decision decoding algorithm,known as gradient algorithm.The idea is based on the iterative Chase algorithm,the optimum decision codeword of last decoding step D(m-1) gained by Chase decoding algorithm is used to substitute the competing codeword C,thus leaving out the step for search of competing codeword C and simplifying the computation of the extrinsic information and soft inputs.Simulation results show that the gradient algorithm is employed to obtain similar decoding performance of TPC with Chase decoding algorithm,and it accelerate decoding procedures the and reduces relatively the decoding complexity.