Research on approximated Log-MAP Algorithm

This paper proposes an approximate calculation for correction function of Log-MAP Algorithm and obtains a well turbo decoding in AWGN channel. The algorithm mainly uses the method of segmenting and fitting for correction function by spline function. The proposed method has solved the difficulties and obstacles resulting from inaccessible calculation of correction function with exponential and logarithm computations. It shows that error correction performance of turbo decoder with the interpolation function to calculate the correction function is the same as that with Log-MAP algorithm and the former algorithm complexity is much obviously lower than the latter.