Two-dimensional bit-stuffing schemes with multiple transformers

We present bit-stuffing schemes which encode arbitrary data sequences into two-dimensional (2-D) constrained arrays. We consider the class of 2-D runlength-limited (RLL) (d, infin) constraints as well as the ´no isolated bits´ (n.i.b.) constraint, both defined on the square lattice. The bit stuffing technique was previously introduced and applied to the class of 2-D (d, infin) constraints. Analytical lower bounds on the rate of these encoders were derived. For d = 1, a more general scheme was analyzed and shown to obtain improved performance. We extend the (1, infin)-construction to (d, infin) constraints where d ges 2. We then suggest a bit-stuffing scheme for the n.i.b. constraint, based on a capacity-achieving scheme for a one-dimensional RLL (0,3) constraint. Simulation results demonstrate the performance of the proposed schemes