Method and apparatus for decoding punctured trellis code modulated data

摘要

An improvement to the decoding of punctured TCM uses standard branch metrics for symbols formed by unpunctured bits and for symbols formed by punctured bits uses a partial distance metric based on decomposition of the I, Q components in the signal constellation space. The disclosed decoding of punctured symbols includes computing a first partial distance metric for each state in a first interval and selecting a survivor path based on the first partial distance metric. In a second interval, a second partial distance metric is computed for each state and a survivor path is selected based on the second partial distance metric. The partial distance metrics are accumulated in the state metrics for each state for a sequence of received symbols. The metric approach is applicable to PSK and QAM applications.