1. A method for processing a signal to detect one or more data bits, said method comprising the steps of: precomputing multi-step branch metrics for a multiple-step trellis for speculative sequences of one or more channel symbols, wherein each of said channel symbols represents one or more data bits; selecting a subset of said precomputed branch metrics for multi-step state transitions based on at least one multi-step decision from at least one corresponding state; and selecting a path having a best path metric for a given state.