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