Second interleaved data is de-interleaved using a second interleaving mapping to obtain encoded data. The second interleaved data includes a copy of constrained data in the same sequence and having the same values as the constrained data. Also, the portion of the second interleaved data that includes the copy of the constrained data satisfies a modulation constraint associated with limiting a number of consecutive events to a maximum number of consecutive events. The encoded data is decoded to obtain first interleaved data and the first interleaved data is de-interleaved using a first interleaving mapping to obtain the constrained data, a copy of which is included in the second interleaved data, where the constrained data satisfies the modulation constraint.