Parameters

h or the lower branch. It probably doesn't matter which method you use. The operation of adding the previous accumulated error metrics to the new branch metrics, comparing the results, and selecting the smaller (smallest) accumulated error metric to be retained for the next time instant is called the add-compare-select operation. The figure below shows the results of processing t = 3: Note that the third channel symbol pair we received had a one-symbol error. The smallest accumulated error metric is a one, and there are two of these. Let's see what happens now at t = 4. The processing is the same as it was for t = 3. The results are shown in the figure: Notice that at t = 4, the path through the trellis of the actual transmitted message, shown in bold, is again associated with the smallest accumulated error metric. Let's look at t = 5: At t = 1, we received 00 2. The only possible channel symbol pairs we could have received are 00 2 and 11 2 . The Hamming distance between 00 2 and 0