Patent ID: 7337383

Claim:
A method for performing a new turbo decoding algorithm using a-posteriori probability p(s,s′|y) in equations (13) for defining the maximum a-posteriori probability MAP, comprising: using a new statistical definition of the MAP logarithm likelihood ratio L(d(k)|y) in equations (18) L ( d ( k ))| y )=ln [Σ (s,s′|d(k)=+1) p ( s,s′|y )] −ln [Σ (s,s′|d(k)=−1) p ( s,s′|y )] equal to the natural logarithm of the ratio of the a-posteriori probability p(s,s′|y) summed over all state transitions s′→s corresponding to the transmitted data d(k)=1 to the p(s,s′|y) summed over all state transitions s′→s corresponding to the transmitted data d(k)=0, using a factorization of the a-posteriori probability p(s,s′|y) in equations (13) into the product of the a-posteriori probabilities p ( s,s′|y )= p ( s|s′,y ( k )) p ( s|y ( j>k )) p ( s′|y ( j<k )), using a turbo decoding forward recursion equation p ( s|y ( j<k ), y ( k ))=Σ all s′ p ( s|s′,y ( k )) p ( s′|y ( j<k )) DM=[−|y(k)−x(k)| 2 /2σ 2 ] which is a quadratic function of y(k), whereby said MAP turbo decoding algorithms provide some of the performance improvements demonstrated in FIG. 5 , 6 using said DX, and whereby this new a-posteriori mathematical framework enables said MAP turbo decoding algorithms to be restructured and to determine the intrinsic information as a function of said DX linear in said y(k).