1. A speech recognition system for recognizing speech, the system comprising: one or more processors; a local-scale decoder operating on the one or more processors, the local-scale decoder configured to generate local-scale soft information from a speech signal; and a broad-scale decoder configured to: receive the local-scale soft information; and generate broad-scale soft information based on the local-scale soft information, wherein the local-scale decoder and the broad-scale decoder are further configured to perform one or more turbo iterations, at least one of the turbo iterations comprising: the local-scale decoder updating the local-scale soft information based on the broad-scale soft information; and the broad-scale decoder updating the broad-scale soft information based on the local-scale soft information, wherein a plurality of hard symbol decisions are generated from one of the local-scale and the broad-scale soft information.