Reduced memory turbo MAP decoding algorithm for non-binary orthogonal signaling

In non-binary turbo decoding combined with non-binary orthogonal signaling such as M-ary FSK, the conditional channel probabilities of the non-binary symbols require M values for each symbol. In this paper, we propose a method which can reduce the backup memory size of the channel values of non-binary orthogonal signaling. And we propose a new turbo decoding method which can reduce the memory for a non-binary turbo MAP decoder. We compare the memory requirements of the proposed algorithms and the bit error rate performance.