Abstract
This paper proposes efficient distance-enhancing constrained codes with parity-check (PC) constraints for data storage channels. We first propose simple and efficient finite-state encoding methods to design various distance-enhancing constrained codes, including a repeated minimum transition runlength (RMTR) code for optical recording channels, as well as a maximum transition run (MTR) code for magnetic recording channels. We further propose a general and systematic code design methodology, which can efficiently combine constrained codes with PC codes. The constrained codes can be any distance-enhancing constrained codes. The PC codes can be any linear binary PC codes. The rates of the designed codes are only a few tenths of a percent below the theoretical maximum. The proposed method enables soft information to be available to the PC decoder and soft decoding of PC codes. Examples of several newly designed distance-enhancing constrained PC codes are illustrated. Simulation results with blu-ray disc (BD) systems show that the proposed new RMTR code and RMTR constrained 4-bit PC code perform 0.2 dB and 0.85 dB better than the standard 17PP code, respectively, at error correction code (ECC) failure rate (EFR) of 10(-12) and high recording density.