1. A receiver device comprising a plurality of maximum a posteriori decoders configured to iteratively compute one or more received input signal sequences, the decoders configured to: calculate backward state initial values from an input signal, store the backward state initial values as a pre-computed backward state metric into a memory; for each iteration of a plurality of iterations, the decoders are further configured to: compute a forward state metric; compute a backward state metric, wherein for each of the plurality of iterations for calculating the backward state metric, the decoders are configured to retrieve from the memory, the initial state values of the backward state metric, and wherein the initial values of the backward state metric are pre-computed from the received input signal independent of the plurality of decoding iterations.