Abstract:
We define the bidirectional distance profile (BDP) of a convolutional code as the
minimum of the distance profiles of the code and its corresponding “reverse” code. We present
tables of codes with the optimum BDP (OBDP), which minimize the average complexity of
bidirectional sequential decoding algorithms. The computer search is accelerated by the facts
that optimum distance profile (ODP) codes of larger memory must have ODP codes of smaller
memory as their “prefixes”, and that OBDP codes can be obtained by “concatenating” ODP
and reverse ODP codes of smaller memory. We compare the performance of OBDP codes and
other codes by simulation.
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