Patent ID: 7055102

Claim:
A method of a turbo decoder using log A Posteriori Probability L(u k ), where L(u k )=f(α k (.), β k (.)), the method comprising: dividing a forward variable α (.) and a backward variable β (.) into a plurality M of parallel segments of size p, q . . . w, where p+q, . . . +w equals the length of a coded word U; simultaneous, parallel calculating the segments of forward variable α (.) of the code word U as follows: α 1 ⁡ ( . ) , … ⁢ , α p ⁡ ( . ) ⁢ ⁢ starting ⁢ ⁢ from ⁢ ⁢ α 0 ⁡ ( . ) α p + 1 ⁡ ( . ) , … ⁢ , α q ⁡ ( . ) ⁢ ⁢ starting ⁢ ⁢ from ⁢ ⁢ α p ⁡ ( . ) ⁢ ⋮ α w + 1 ⁡ ( . ) , … ⁢ , α K ⁡ ( . ) ⁢ ⁢ starting ⁢ ⁢ from ⁢ ⁢ α w ⁡ ( . ) ; and the segments of the backward variable β (.) of the code word U as follows: β K - 1 ⁡ ( . ) , … ⁢ , β w + 1 ⁡ ( . ) ⁢ ⁢ starting ⁢ ⁢ from ⁢ ⁢ β K ⁡ ( . ) β w ⁡ ( . ) , … ⁢ , β v + 1 ⁡ ( . ) ⁢ ⁢ starting ⁢ ⁢ ⁢ from ⁢ ⁢ β w + 1 ⁡ ( . ) ⋮ β q ⁡ ( . ) , … ⁢ , β 1 ⁡ ( . ) ⁢ ⁢ starting ⁢ ⁢ ⁢ from ⁢ ⁢ β q + 1 ⁡ ( . ) ; and calculating L(u k ) using the parallel calculated segments of α (.) and β (.).