Construction of Constrained Codes for State-Independent Decoding

Constrained sequence codes are widely used to meet constraints imposed by digital storage and communication systems. This paper develops an algorithm for the construction of constrained codes that admit state-independent decoding. By partitioning the code into a group of alphabets, one for each state, a codebook is developed using this algorithm that will allow the code to be decoded at the receiver without the need for state information. Finally, we use this algorithm to construct DC-free runlength-limited (RLL) codes, and we present two highly efficient state-independent decodable DC-free RLL codes.