The performance of a severely punctured convolutional code, some high rate distance-two block codes, and a Hamming code with maximum likelihood decoding

A severely punctured version of the well known rate-1/2, constraint length 7 convolutional code is considered for transmission of short to moderate length messages. Transmissions are assumed to be truncated by use of tail bits. By severely punctured the authors mean that the only redundancy conveyed is contained in the tail. It is shown that the resulting codes are high rate distance-2 codes and for certain message lengths they are cyclic. The figure of merit assumed is the probability of not correctly decoding a message, and, with maximum likelihood decoding, significant coding gains are demonstrated. In one case, a Hamming code results and its performance is determined. The coding gains observed range from 3.8 dB for the Hamming code to 2.4 dB for the longest distance-2 code considered, a (5040, 5034) code