Minimum distance bounds for multiple-serially concatenated code ensembles

It has recently been shown that the minimum distance of the ensemble of repeat multiple accumulate codes grows linearly with block length. In this paper, we present a method to obtain the distance growth rate coefficient of multiple-serially concatenated code ensembles and determine the growth rate coefficient of the rate 1/2 double-serially concatenated code consisting of an outer memory one convolutional code followed by two accumulators. We compare both the growth rate of the minimum distance, as well as the convergence behavior, of this code with rate 1/2 repeat multiple accumulate codes, and we show that repeat multiple accumulate codes have better minimum distance growth but worse performance in terms of convergence.