On the effect of imperfect interleaving for the Gilbert-Elliott channel

By using the Gilbert-Elliott (1960, 1963) model to study the performance of block-coded transmission over the land mobile channel, a new analytical expression illustrating the effect of various parameters, e,g., mobile speed, delay constraint, and parameters for the error correcting code, is found. Comparisons between the results obtained by this analytical expression and results obtained by computer simulations show that the analytical results are accurate for a broad range of channel parameters. The Gilbert-Elliott model is then used to compare the performance of different binary BCH codes when the delay constraint does not allow the assumption of infinite interleaving. In contrast to the memoryless case, where the performance typically is improved with increased block length, short codes are found to be as good, or even superior, due to the fact that the interleaver works better for shorter codes.