1. A system for processing data, comprising: a second de-interleaver configured to de-interleave second interleaved data using a second interleaving mapping to obtain encoded data, wherein: de-interleaving the second interleaved data using the second interleaving mapping includes reordering contents of the second interleaved data using the second interleaving mapping; and at least a portion of the second interleaved data satisfies a modulation constraint associated with limiting a number of consecutive events to a maximum number of consecutive events; a decoder configured to decode the encoded data to obtain first interleaved data; and a first de-interleaver configured to de-interleave the first interleaved data using a first interleaving mapping to obtain constrained data, a copy of which is included in the second interleaved data, wherein the constrained data satisfies the modulation constraint and de-interleaving the first interleaved data using the first interleaving mapping to obtain the constrained data includes reordering the first interleaved data using the first interleaving mapping to obtain the constrained data in a same sequence as the sequence of the copy included in the second interleaved data.