  In this paper, we propose a construction for multi-kernel polar codes based
on the maximization of the minimum distance. Compared to the original
construction based on density evolution, our new design shows particular
advantages for short code lengths, where the polarization effect has less
impact on the performance than the distances of the code. We introduce and
compute the minimum-distance profile and provide a simple greedy algorithm for
the code design. Compared to state-of-the-art punctured or shortened Arikan
polar codes, multi-kernel polar codes with our new design show significantly
improved error-rate performance.
