Convolutional coding for bandlimited channels

The application of convolutional codes for finite intersymbol interference (ISI) channels is considered. The performance of a bandlimited communicatio n system in the presence of additive white Gaussian noise depends on the mi nimum Euclidean distance d(min) between different signal sequences. To furt her increase d(min), convolutional or trellis coding could be used. Search results indicate that the encoder with the best free distance does not alwa ys give the best coded distance when combined with an ISI channel. It has b een seen from the results for several ISI channels that moderate coding gai ns can be obtained if the channel and the encoder are properly matched. Fur thermore, it has been observed that if the channel is a maximum distance on e, then the resulting coded distance is usually higher than that for a non- maximum distance channel.