Abstract
A new class of exact-repair regenerating codes is constructed by combining two layers of erasure correction codes together with combinatorial block designs. The proposed codes have the "uncoded repair" property where the nodes participating in the repair simply transfer part of the stored data directly, without performing any computation. The layered error correction structure results in a low-complexity decoding process. An analysis of our coding scheme is presented. This construction is able to achieve better performance than time-sharing between the minimum storage regenerating codes and the minimum repair-bandwidth regenerating codes.