Patent ID: 6961921
Filing Date: 2005-11-01
Classification: H03M

Abstract:
1. A method employed by a decoder for calculating forward and reverse metrics required for performing an output calculation to accurately determine binary states of received signals, comprising the steps of: (a) performing the forward metric calculations in two stages, wherein a first group of the forward metric calculations are calculated in a first stage followed by a second group of forward metric calculations being calculated in a second stage; (b) storing the metric calculations obtained in step (a) in a memory; (c) reading the forward metrics calculated during the first stage from the memory for use with reverse metric values to perform the an output calculation; (d) performing the reverse metric calculations in the second stage, following the first stage; (e) performing a second half of forward metric calculations as said reverse calculations are being performed; and (f) storing each of the forward metric calculations performed in the second stage into a memory location of said memory that a forward metric calculated during the first stage is being read out for use in an output calculation.