Memory reduced MAP decoding for double-binary turbo decoder

In this paper, we proposed the branch metric recovery scheme to reduce the memory requirement of MAP decoding for double-binary convolutional turbo code. The proposed technique exploits the fact that huge memory size is required to store the branch metrics in double-binary convolutional turbo decoder. In the proposed method, rather than storing the original branch metrics, the partial terms of the branch metric are stored and the branch metrics are recovered with simple additions. The implementation results based on the proposed technique are presented to show the extremely low overhead compared to the huge memory reduction.