Does the Viterbi IP support 1/3 mother code with high puncture rate?

Description

Yes, the Viterbi IP supports 1/3 mother code with a high puncture rate (e.g., 70/72 code rate). However, because of the high error rate, short message frame, tailbiting termination, and if the traceback (TB) is not long enough, the IP may not correctly predict the trellis starting/ending point, and the IP eventually decodes the frame incorrectly.

Resolution

Assuming the traceback (TB) is 105 bits, the message frame length is 70 bits, encoded using tailbiting termination, and the code rate is 70/72. In this case, the Viterbi decoder is very poor at correcting errors.  Therefore, each input frame must feed consecutively three times (two traceback lengths TB0 TB1), followed by a number of zeros (TB2). The first and second output frames may still contain errors because the IP cannot predict the trellis starting/ending point correctly, but with no error at the third output frame. Therefore, ignore the first and second output frames for this case.