Lossless sliding-block compression of constrained systems

A method is presented for designing lossless sliding-block compression schemes that map constrained sequences onto unconstrained ones. The new compression scheme is incorporated into a coding technique for noisy constrained channels, which has applications to magnetic and optical storage. As suggested previously by Immink (see ibid., vol.43, p.1389-99, 1997), the use of a lossless compression code can improve the performance of a modified concatenation scheme where the positions of the error-correcting code and constrained code are reversed (primarily in order to eliminate error propagation due to the constrained code). Examples are presented that demonstrate the advantage of using sliding-block compression over block compression in a noisy constrained setting.